Merge branch 'mjog/558-webkit-shared-process-redux' into 'mainline'

Webkit shared process redux

See merge request GNOME/geary!565

meson.build

@@ -56,7 +56,7 @@ valac = meson.get_compiler('vala')
 target_vala = '0.48.6'
 target_glib = '2.64'
 target_gtk = '3.24.7'
-target_webkit = '2.26'
+target_webkit = '2.28'
 
 if not valac.version().version_compare('>=' + target_vala)
   error('Vala does not meet minimum required version: ' + target_vala)

po/POTFILES.in

@@ -37,7 +37,6 @@ src/client/application/goa-mediator.vala
 src/client/application/main.vala
 src/client/application/secret-mediator.vala
 src/client/client-action.vala
-src/client/components/client-web-view.vala
 src/client/components/components-attachment-pane.vala
 src/client/components/components-conversation-actions.vala
 src/client/components/components-conversation-action-bar.vala
@@ -52,6 +51,7 @@ src/client/components/components-problem-report-info-bar.vala
 src/client/components/components-reflow-box.c
 src/client/components/components-search-bar.vala
 src/client/components/components-validator.vala
+src/client/components/components-web-view.vala
 src/client/components/count-badge.vala
 src/client/components/folder-popover.vala
 src/client/components/icon-factory.vala

src/client/accounts/accounts-editor-edit-pane.vala

@@ -718,7 +718,7 @@ internal class Accounts.RemoveMailboxCommand : Application.Command {
 internal class Accounts.SignatureChangedCommand : Application.Command {
 
 
-    private ClientWebView signature_view;
+    private Components.WebView signature_view;
     private Geary.AccountInformation account;
 
     private string old_value;
@@ -728,7 +728,7 @@ internal class Accounts.SignatureChangedCommand : Application.Command {
     private bool new_enabled = false;
 
 
-    public SignatureChangedCommand(ClientWebView signature_view,
+    public SignatureChangedCommand(Components.WebView signature_view,
                                    Geary.AccountInformation account) {
         this.signature_view = signature_view;
         this.account = account;

src/client/accounts/accounts-signature-web-view.vala

@@ -8,14 +8,14 @@
 /**
  * A class for editing signatures in the accounts editor.
  */
-public class Accounts.SignatureWebView : ClientWebView {
+public class Accounts.SignatureWebView : Components.WebView {
 
 
     private static WebKit.UserScript? app_script = null;
 
     public static new void load_resources()
         throws GLib.Error {
-        SignatureWebView.app_script = ClientWebView.load_app_script(
+        SignatureWebView.app_script = Components.WebView.load_app_script(
             "signature-web-view.js"
         );
     }

src/client/application/application-controller.vala

@@ -134,13 +134,12 @@ internal class Application.Controller :
         this.upgrade_dialog = new UpgradeDialog(application);
 
         // Initialise WebKit and WebViews
-        ClientWebView.init_web_context(
+        Components.WebView.init_web_context(
             this.application.config,
             this.application.get_web_extensions_dir(),
             this.application.get_user_cache_directory().get_child("web-resources")
         );
-
+        Components.WebView.load_resources(
-        ClientWebView.load_resources(
             this.application.get_user_config_directory()
         );
         Composer.WebView.load_resources();

src/client/application/main.vala

@@ -5,12 +5,6 @@
  */
 
 int main(string[] args) {
-    // Temporary workaround for WebKitGTK deprecation of the
-    // shared-secondary process model. Pull this out in 3.36 when the
-    // proper fix lands. See GNOME/geary#558.
-    Environment.set_variable("WEBKIT_USE_SINGLE_WEB_PROCESS", "1", true);
-
-
     // Init logging right up front so as to capture as many log
     // messages as possible
     Geary.Logging.init();

src/client/components/components-web-view.vala

@@ -1,6 +1,6 @@
 /*
- * Copyright 2016 Software Freedom Conservancy Inc.
+ * Copyright © 2016 Software Freedom Conservancy Inc.
- * Copyright 2016 Michael Gratton <mike@vee.net>
+ * Copyright © 2016-2020 Michael Gratton <mike@vee.net>
  *
  * This software is licensed under the GNU Lesser General Public License
  * (version 2.1 or later). See the COPYING file in this distribution.
@@ -14,7 +14,7 @@
  * integration, Inspector support, and remote and inline image
  * handling.
  */
-public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
+public abstract class Components.WebView : WebKit.WebView, Geary.BaseInterface {
 
 
     /** URI Scheme and delimiter for internal resource loads. */
@@ -26,13 +26,17 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
     /** URI Scheme and delimiter for images loaded by Content-ID. */
     public const string CID_URL_PREFIX = "cid:";
 
+    // Keep these in sync with GearyWebExtension
+    private const string MESSAGE_RETURN_VALUE_NAME = "__return__";
+    private const string MESSAGE_EXCEPTION_NAME = "__exception__";
+
     // WebKit message handler names
-    private const string COMMAND_STACK_CHANGED = "commandStackChanged";
+    private const string COMMAND_STACK_CHANGED = "command_stack_changed";
-    private const string CONTENT_LOADED = "contentLoaded";
+    private const string CONTENT_LOADED = "content_loaded";
-    private const string DOCUMENT_MODIFIED = "documentModified";
+    private const string DOCUMENT_MODIFIED = "document_modified";
-    private const string PREFERRED_HEIGHT_CHANGED = "preferredHeightChanged";
+    private const string PREFERRED_HEIGHT_CHANGED = "preferred_height_changed";
-    private const string REMOTE_IMAGE_LOAD_BLOCKED = "remoteImageLoadBlocked";
+    private const string REMOTE_IMAGE_LOAD_BLOCKED = "remote_image_load_blocked";
-    private const string SELECTION_CHANGED = "selectionChanged";
+    private const string SELECTION_CHANGED = "selection_changed";
 
     private const double ZOOM_DEFAULT = 1.0;
     private const double ZOOM_FACTOR = 0.1;
@@ -65,7 +69,6 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
     private static WebKit.UserStyleSheet? user_stylesheet = null;
 
     private static WebKit.UserScript? script = null;
-    private static WebKit.UserScript? allow_remote_images = null;
 
 
     /**
@@ -76,23 +79,18 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
                                         File cache_dir) {
         WebsiteDataManager data_manager = new WebsiteDataManager(cache_dir.get_path());
         WebKit.WebContext context = new WebKit.WebContext.with_website_data_manager(data_manager);
-#if HAS_WEBKIT_SHARED_PROC
-        // Use a shared process so we don't spawn N WebProcess instances
-        // when showing N messages in a conversation.
-        context.set_process_model(WebKit.ProcessModel.SHARED_SECONDARY_PROCESS);
-#endif
         // Use the doc viewer model since each web view instance only
         // ever shows a single HTML document.
         context.set_cache_model(WebKit.CacheModel.DOCUMENT_VIEWER);
 
         context.register_uri_scheme("cid", (req) => {
-                ClientWebView? view = req.get_web_view() as ClientWebView;
+                WebView? view = req.get_web_view() as WebView;
                 if (view != null) {
                     view.handle_cid_request(req);
                 }
             });
         context.register_uri_scheme("geary", (req) => {
-                ClientWebView? view = req.get_web_view() as ClientWebView;
+                WebView? view = req.get_web_view() as WebView;
                 if (view != null) {
                     view.handle_internal_request(req);
                 }
@@ -113,25 +111,22 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
                 update_spellcheck(context, config);
             });
 
-        ClientWebView.default_context = context;
+        WebView.default_context = context;
     }
 
     /**
-     * Loads static resources used by ClientWebView.
+     * Loads static resources used by WebView.
      */
     public static void load_resources(GLib.File user_dir)
         throws GLib.Error {
-        ClientWebView.script = load_app_script(
+        WebView.script = load_app_script(
-            "client-web-view.js"
+            "components-web-view.js"
-        );
-        ClientWebView.allow_remote_images = load_app_script(
-            "client-web-view-allow-remote-images.js"
         );
 
         foreach (string name in new string[] { USER_CSS, USER_CSS_LEGACY }) {
             GLib.File stylesheet = user_dir.get_child(name);
             try {
-                ClientWebView.user_stylesheet = load_user_stylesheet(stylesheet);
+                WebView.user_stylesheet = load_user_stylesheet(stylesheet);
                 break;
             } catch (GLib.IOError.NOT_FOUND err) {
                 // All good, try the next one or just exit
@@ -200,8 +195,23 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
     }
 
 
-    /** Delegate for UserContentManager message callbacks. */
+    /**
-    public delegate void JavaScriptMessageHandler(WebKit.JavascriptResult js_result);
+     * Delegate for message handler callbacks.
+     *
+     * @see register_message_callback
+     */
+    protected delegate void MessageCallback(GLib.Variant? parameters);
+
+    // Work around for not being able to put delegates in a Gee collection.
+    private class MessageCallable {
+
+        public unowned MessageCallback handler;
+
+        public MessageCallable(MessageCallback handler) {
+            this.handler = handler;
+        }
+
+    }
 
     /**
      * Determines if the view's content has been fully loaded.
@@ -266,8 +276,8 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
     private Gee.Map<string,Geary.Memory.Buffer> internal_resources =
         new Gee.HashMap<string,Geary.Memory.Buffer>();
 
-    private Gee.List<ulong> registered_message_handlers =
+    private Gee.Map<string,MessageCallable> message_handlers =
-        new Gee.LinkedList<ulong>();
+        new Gee.HashMap<string,MessageCallable>();
 
     private double webkit_reported_height = 0;
 
@@ -299,8 +309,9 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
     public signal void remote_image_load_blocked();
 
 
-    protected ClientWebView(Application.Configuration config,
+    protected WebView(Application.Configuration config,
-                            WebKit.UserContentManager? custom_manager = null) {
+                      WebKit.UserContentManager? custom_manager = null,
+                      WebView? related = null) {
         WebKit.Settings setts = new WebKit.Settings();
         setts.allow_modal_dialogs = false;
         setts.default_charset = "UTF-8";
@@ -321,70 +332,45 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
 
         WebKit.UserContentManager content_manager =
              custom_manager ?? new WebKit.UserContentManager();
-        content_manager.add_script(ClientWebView.script);
+        content_manager.add_script(WebView.script);
-        if (ClientWebView.user_stylesheet != null) {
+        if (WebView.user_stylesheet != null) {
-            content_manager.add_style_sheet(ClientWebView.user_stylesheet);
+            content_manager.add_style_sheet(WebView.user_stylesheet);
         }
 
         Object(
-            web_context: ClientWebView.default_context,
+            settings: setts,
             user_content_manager: content_manager,
-            settings: setts
+            web_context: WebView.default_context
         );
         base_ref();
-
+        init(config);
-        // XXX get the allow prefix from the extension somehow
-
-        this.decide_policy.connect(on_decide_policy);
-        this.web_process_terminated.connect((reason) => {
-                warning("Web process crashed: %s", reason.to_string());
-            });
-
-        register_message_handler(
-            COMMAND_STACK_CHANGED, on_command_stack_changed
-        );
-        register_message_handler(
-            CONTENT_LOADED, on_content_loaded
-        );
-        register_message_handler(
-            DOCUMENT_MODIFIED, on_document_modified
-        );
-        register_message_handler(
-            PREFERRED_HEIGHT_CHANGED, on_preferred_height_changed
-        );
-        register_message_handler(
-            REMOTE_IMAGE_LOAD_BLOCKED, on_remote_image_load_blocked
-        );
-        register_message_handler(
-            SELECTION_CHANGED, on_selection_changed
-        );
-
-        // Manage zoom level, ensure it's sane
-        config.bind(Application.Configuration.CONVERSATION_VIEWER_ZOOM_KEY, this, "zoom_level");
-        if (this.zoom_level < ZOOM_MIN) {
-            this.zoom_level = ZOOM_MIN;
-        } else if (this.zoom_level > ZOOM_MAX) {
-            this.zoom_level = ZOOM_MAX;
-        }
-        this.scroll_event.connect(on_scroll_event);
-
-        // Watch desktop font settings
-        Settings system_settings = config.gnome_interface;
-        system_settings.bind("document-font-name", this,
-                             "document-font", SettingsBindFlags.DEFAULT);
-        system_settings.bind("monospace-font-name", this,
-                             "monospace-font", SettingsBindFlags.DEFAULT);
     }
 
-    ~ClientWebView() {
+    /**
+     * Constructs a new web view with a new shared WebProcess.
+     *
+     * The new view will use the same WebProcess, settings and content
+     * manager as the given related view's.
+     *
+     * @see WebKit.WebView.WebView.with_related_view
+     */
+    protected WebView.with_related_view(Application.Configuration config,
+                                        WebView related) {
+        Object(
+            related_view: related,
+            settings: related.get_settings(),
+            user_content_manager: related.user_content_manager
+        );
+        base_ref();
+        init(config);
+    }
+
+    ~WebView() {
         base_unref();
     }
 
     public override void destroy() {
-        foreach (ulong id in this.registered_message_handlers) {
+        this.message_handlers.clear();
-            this.user_content_manager.disconnect(id);
-        }
-        this.registered_message_handlers.clear();
         base.destroy();
     }
 
@@ -400,9 +386,7 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
      * Returns the view's content as an HTML string.
      */
     public async string? get_html() throws Error {
-        return Util.JS.to_string(
+        return yield call_returning<string?>(Util.JS.callable("getHtml"), null);
-            yield call(Util.JS.callable("geary.getHtml"), null)
-        );
     }
 
     /**
@@ -433,20 +417,14 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
      * effect.
      */
     public void allow_remote_image_loading() {
-        // Use a separate script here since we need to update the
+        this.run_javascript.begin("_gearyAllowRemoteResourceLoads = true", null);
-        // value of window.geary.allow_remote_image_loading after it
-        // was first created by client-web-view.js (which is loaded at
-        // the start of page load), but before the page load is
-        // started (so that any remote images present are actually
-        // loaded).
-        this.user_content_manager.add_script(ClientWebView.allow_remote_images);
     }
 
     /**
      * Load any remote images previously that were blocked.
      */
     public void load_remote_images() {
-        this.call.begin(Util.JS.callable("geary.loadRemoteImages"), null);
+        this.call_void.begin(Util.JS.callable("loadRemoteImages"), null);
     }
 
     /**
@@ -491,40 +469,192 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
     public new async void set_editable(bool enabled,
                                        Cancellable? cancellable)
         throws Error {
-        yield call(
+        yield call_void(
-            Util.JS.callable("geary.setEditable").bool(enabled), cancellable
+            Util.JS.callable("setEditable").bool(enabled), cancellable
         );
     }
 
     /**
      * Invokes a {@link Util.JS.Callable} on this web view.
+     *
+     * This calls the given callable on the `geary` object for the
+     * current view, any returned value are ignored.
      */
-    protected async JSC.Value call(Util.JS.Callable target,
+    protected async void call_void(Util.JS.Callable target,
                                    GLib.Cancellable? cancellable)
         throws GLib.Error {
-        WebKit.JavascriptResult result = yield run_javascript(
+        yield call_impl(target, cancellable);
-            target.to_string(), cancellable
-        );
-        return result.get_js_value();
     }
 
     /**
-     * Convenience function for registering and connecting JS messages.
+     * Invokes a {@link Util.JS.Callable} on this web view.
+     *
+     * This calls the given callable on the `geary` object for the
+     * current view. The value returned by the call is returned by
+     * this method.
+     *
+     * The type parameter `T` must match the type returned by the
+     * call, else an error is thrown. Only simple nullable value types
+     * are supported for T, for more complex return types (arrays,
+     * dictionaries, etc) specify {@link GLib.Variant} for `T` and
+     * manually parse that.
      */
-    protected inline void register_message_handler(string name,
+    protected async T call_returning<T>(Util.JS.Callable target,
-                                                   JavaScriptMessageHandler handler) {
+                                        GLib.Cancellable? cancellable)
-        // XXX can't use the delegate directly, see b.g.o Bug
+        throws GLib.Error {
-        // 604781. However the workaround below creates a circular
+        WebKit.UserMessage? response = yield call_impl(target, cancellable);
-        // reference, causing ClientWebView instances to leak. So to
+        if (response == null) {
-        // work around that we need to record handler ids and
+            throw new Util.JS.Error.TYPE(
-        // disconnect them when being destroyed.
+                "Method call %s did not return a value", target.to_string()
-        ulong id = this.user_content_manager.script_message_received[name].connect(
+            );
-            (result) => { handler(result); }
-        );
-        this.registered_message_handlers.add(id);
-        if (!this.user_content_manager.register_script_message_handler(name)) {
-            debug("Failed to register script message handler: %s", name);
         }
+        GLib.Variant? param = response.parameters;
+        T ret_value = null;
+        var ret_type = typeof(T);
+        if (ret_type == typeof(GLib.Variant)) {
+            ret_value = param;
+        } else {
+            if (param != null && param.get_type().is_maybe()) {
+                param = param.get_maybe();
+            }
+            if (param != null) {
+                // Since these replies are coming from JS via
+                // Util.JS.value_to_variant, they will only be one of
+                // string, double, bool, array or dict
+                var param_type = param.classify();
+                if (ret_type == typeof(string) && param_type == STRING) {
+                    ret_value = param.get_string();
+                } else if (ret_type == typeof(bool) && param_type == BOOLEAN) {
+                    ret_value = (bool?) param.get_boolean();
+                } else if (ret_type == typeof(int) && param_type == DOUBLE) {
+                    ret_value = (int?) ((int) param.get_double());
+                } else if (ret_type == typeof(short) && param_type == DOUBLE) {
+                    ret_value = (short?) ((short) param.get_double());
+                } else if (ret_type == typeof(char) && param_type == DOUBLE) {
+                    ret_value = (char?) ((char) param.get_double());
+                } else if (ret_type == typeof(long) && param_type == DOUBLE) {
+                    ret_value = (long?) ((long) param.get_double());
+                } else if (ret_type == typeof(int64) && param_type == DOUBLE) {
+                    ret_value = (int64?) ((int64) param.get_double());
+                } else if (ret_type == typeof(uint) && param_type == DOUBLE) {
+                    ret_value = (uint?) ((uint) param.get_double());
+                } else if (ret_type == typeof(uchar) && param_type == DOUBLE) {
+                    ret_value = (uchar?) ((uchar) param.get_double());
+                } else if (ret_type == typeof(ushort) && param_type == DOUBLE) {
+                    ret_value = (ushort?) ((ushort) param.get_double());
+                } else if (ret_type == typeof(ulong) && param_type == DOUBLE) {
+                    ret_value = (ulong?) ((ulong) param.get_double());
+                } else if (ret_type == typeof(uint64) && param_type == DOUBLE) {
+                    ret_value = (uint64?) ((uint64) param.get_double());
+                } else if (ret_type == typeof(double) && param_type == DOUBLE) {
+                    ret_value = (double?) param.get_double();
+                } else if (ret_type == typeof(float) && param_type == DOUBLE) {
+                    ret_value = (float?) ((float) param.get_double());
+                } else {
+                    throw new Util.JS.Error.TYPE(
+                        "%s is not a supported type for %s",
+                        ret_type.name(), param_type.to_string()
+                    );
+                }
+            }
+        }
+        return ret_value;
+    }
+
+    /**
+     * Registers a callback for a specific WebKit user message.
+     */
+    protected void register_message_callback(string name,
+                                             MessageCallback handler) {
+        this.message_handlers.set(name, new MessageCallable(handler));
+    }
+
+    private void init(Application.Configuration config) {
+        // XXX get the allow prefix from the extension somehow
+
+        this.decide_policy.connect(on_decide_policy);
+        this.web_process_terminated.connect((reason) => {
+                warning("Web process crashed: %s", reason.to_string());
+            });
+
+        register_message_callback(
+            COMMAND_STACK_CHANGED, on_command_stack_changed
+        );
+        register_message_callback(
+            CONTENT_LOADED, on_content_loaded
+        );
+        register_message_callback(
+            DOCUMENT_MODIFIED, on_document_modified
+        );
+        register_message_callback(
+            PREFERRED_HEIGHT_CHANGED, on_preferred_height_changed
+        );
+        register_message_callback(
+            REMOTE_IMAGE_LOAD_BLOCKED, on_remote_image_load_blocked
+        );
+        register_message_callback(
+            SELECTION_CHANGED, on_selection_changed
+        );
+
+        this.user_message_received.connect(this.on_message_received);
+
+        // Manage zoom level, ensure it's sane
+        config.bind(Application.Configuration.CONVERSATION_VIEWER_ZOOM_KEY, this, "zoom_level");
+        if (this.zoom_level < ZOOM_MIN) {
+            this.zoom_level = ZOOM_MIN;
+        } else if (this.zoom_level > ZOOM_MAX) {
+            this.zoom_level = ZOOM_MAX;
+        }
+        this.scroll_event.connect(on_scroll_event);
+
+        // Watch desktop font settings
+        Settings system_settings = config.gnome_interface;
+        system_settings.bind("document-font-name", this,
+                             "document-font", SettingsBindFlags.DEFAULT);
+        system_settings.bind("monospace-font-name", this,
+                             "monospace-font", SettingsBindFlags.DEFAULT);
+    }
+
+    private async WebKit.UserMessage? call_impl(Util.JS.Callable target,
+                                                GLib.Cancellable? cancellable)
+        throws GLib.Error {
+        WebKit.UserMessage? response = yield send_message_to_page(
+            target.to_message(), cancellable
+        );
+        if (response != null) {
+            var response_name = response.name;
+            if (response_name == MESSAGE_EXCEPTION_NAME) {
+                var exception = new GLib.VariantDict(response.parameters);
+                var name = exception.lookup_value("name", GLib.VariantType.STRING) as string;
+                var message = exception.lookup_value("message", GLib.VariantType.STRING) as string;
+                var backtrace = exception.lookup_value("backtrace_string", GLib.VariantType.STRING) as string;
+                var source = exception.lookup_value("source_uri", GLib.VariantType.STRING) as string;
+                var line = exception.lookup_value("line_number", GLib.VariantType.UINT32);
+                var column = exception.lookup_value("column_number", GLib.VariantType.UINT32);
+
+                var log_message = "Method call %s raised %s exception at %s:%d:%d: %s".printf(
+                    target.to_string(),
+                    name ?? "unknown",
+                    source ?? "unknown",
+                    (line != null ? (int) line.get_uint32() : -1),
+                    (column != null ? (int) column.get_uint32() : -1),
+                    message ?? "unknown"
+                );
+                debug(log_message);
+                if (backtrace != null) {
+                    debug(backtrace);
+                }
+
+                throw new Util.JS.Error.EXCEPTION(log_message);
+            } else if (response_name != MESSAGE_RETURN_VALUE_NAME) {
+                throw new Util.JS.Error.TYPE(
+                    "Method call %s returned unknown name: %s",
+                    target.to_string(),
+                    response_name
+                );
+            }
+        }
+        return response;
     }
 
     private void handle_cid_request(WebKit.URISchemeRequest request) {
@@ -625,12 +755,12 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
         return false;
     }
 
-    private void on_preferred_height_changed(WebKit.JavascriptResult result) {
+    private void on_preferred_height_changed(GLib.Variant? parameters) {
         double height = this.webkit_reported_height;
-        try {
+        if (parameters != null && parameters.classify() == DOUBLE) {
-            height = Util.JS.to_double(result.get_js_value());
+            height = parameters.get_double();
-        } catch (Util.JS.Error err) {
+        } else {
-            debug("Could not get preferred height: %s", err.message);
+            warning("Could not get JS preferred height");
         }
 
         if (this.webkit_reported_height != height) {
@@ -639,43 +769,66 @@ public abstract class ClientWebView : WebKit.WebView, Geary.BaseInterface {
         }
     }
 
-    private void on_command_stack_changed(WebKit.JavascriptResult result) {
+    private void on_command_stack_changed(GLib.Variant? parameters) {
-        try {
+        if (parameters != null &&
-            string[] values =
+            parameters.is_container() &&
-                Util.JS.to_string(result.get_js_value()).split(",");
+            parameters.n_children() == 2) {
-            command_stack_changed(values[0] == "true", values[1] == "true");
+            GLib.Variant can_undo = parameters.get_child_value(0);
-        } catch (Util.JS.Error err) {
+            GLib.Variant can_redo = parameters.get_child_value(1);
-            debug("Could not get command stack state: %s", err.message);
+            command_stack_changed(
+                can_undo.classify() == BOOLEAN && can_undo.get_boolean(),
+                can_redo.classify() == BOOLEAN && can_redo.get_boolean()
+            );
+        } else {
+            warning("Could not get JS command stack state");
         }
     }
 
-    private void on_document_modified(WebKit.JavascriptResult result) {
+    private void on_document_modified(GLib.Variant? parameters) {
         document_modified();
     }
 
-    private void on_remote_image_load_blocked(WebKit.JavascriptResult result) {
+    private void on_remote_image_load_blocked(GLib.Variant? parameters) {
         remote_image_load_blocked();
     }
 
-    private void on_content_loaded(WebKit.JavascriptResult result) {
+    private void on_content_loaded(GLib.Variant? parameters) {
         this.is_content_loaded = true;
         content_loaded();
     }
 
-    private void on_selection_changed(WebKit.JavascriptResult result) {
+    private void on_selection_changed(GLib.Variant? parameters) {
-        try {
+        if (parameters != null && parameters.classify() == BOOLEAN) {
-            bool has_selection = Util.JS.to_bool(result.get_js_value());
+            selection_changed(parameters.get_boolean());
-            // Avoid firing multiple notifies if the value hasn't
+        } else {
-            // changed
+            warning("Could not get JS selection value");
-            if (this.has_selection != has_selection) {
-                this.has_selection = has_selection;
-            }
-            selection_changed(has_selection);
-        } catch (Util.JS.Error err) {
-            debug("Could not get selection content: %s", err.message);
         }
     }
 
+    private bool on_message_received(WebKit.UserMessage message) {
+        if (message.name == MESSAGE_EXCEPTION_NAME) {
+            var detail = new GLib.VariantDict(message.parameters);
+            var name = detail.lookup_value("name", GLib.VariantType.STRING) as string;
+            var log_message = detail.lookup_value("message", GLib.VariantType.STRING) as string;
+            warning(
+                "Error sending message from JS: %s: %s",
+                name ?? "unknown",
+                log_message ?? "unknown"
+            );
+        } else if (this.message_handlers.has_key(message.name)) {
+            debug(
+                "Message received: %s(%s)",
+                message.name,
+                message.parameters != null ? message.parameters.print(true) : ""
+            );
+            MessageCallable callback = this.message_handlers.get(message.name);
+            callback.handler(message.parameters);
+        } else {
+            warning("Message with unknown handler received: %s", message.name);
+        }
+        return true;
+    }
+
 }
 
 // XXX this needs to be moved into the libsoup bindings

src/client/composer/composer-web-view.vala

@@ -9,7 +9,7 @@
 /**
  * A WebView for editing messages in the composer.
  */
-public class Composer.WebView : ClientWebView {
+public class Composer.WebView : Components.WebView {
 
     /** HTML id used for the main text section of the message body. */
     public const string BODY_HTML_ID = "geary-body";
@@ -33,8 +33,8 @@ public class Composer.WebView : ClientWebView {
     private const string SPACER = "<div><br /></div>";
 
     // WebKit message handler names
-    private const string CURSOR_CONTEXT_CHANGED = "cursorContextChanged";
+    private const string CURSOR_CONTEXT_CHANGED = "cursor_context_changed";
-    private const string DRAG_DROP_RECEIVED = "dragDropReceived";
+    private const string DRAG_DROP_RECEIVED = "drag_drop_received";
 
     /**
      * Encapsulates editing-related state for a specific DOM node.
@@ -112,10 +112,10 @@ public class Composer.WebView : ClientWebView {
 
     public static new void load_resources()
         throws Error {
-        WebView.app_style = ClientWebView.load_app_stylesheet(
+        WebView.app_style = Components.WebView.load_app_stylesheet(
             "composer-web-view.css"
         );
-        WebView.app_script = ClientWebView.load_app_script(
+        WebView.app_script = Components.WebView.load_app_script(
             "composer-web-view.js"
         );
     }
@@ -152,8 +152,8 @@ public class Composer.WebView : ClientWebView {
         this.user_content_manager.add_style_sheet(WebView.app_style);
         this.user_content_manager.add_script(WebView.app_script);
 
-        register_message_handler(CURSOR_CONTEXT_CHANGED, on_cursor_context_changed);
+        register_message_callback(CURSOR_CONTEXT_CHANGED, on_cursor_context_changed);
-        register_message_handler(DRAG_DROP_RECEIVED, on_drag_drop_received);
+        register_message_callback(DRAG_DROP_RECEIVED, on_drag_drop_received);
 
         // XXX this is a bit of a hack given the docs for is_empty,
         // above
@@ -202,8 +202,8 @@ public class Composer.WebView : ClientWebView {
      * Returns the view's content as HTML without being cleaned.
      */
     public async string? get_html_for_draft() throws Error {
-        return Util.JS.to_string(
+        return yield call_returning<string?>(
-            yield call(Util.JS.callable("geary.getHtml").bool(false), null)
+            Util.JS.callable("getHtml").bool(false), null
         );
     }
 
@@ -213,8 +213,8 @@ public class Composer.WebView : ClientWebView {
     public void set_rich_text(bool enabled) {
         this.is_rich_text = enabled;
         if (this.is_content_loaded) {
-            this.call.begin(
+            this.call_void.begin(
-                Util.JS.callable("geary.setRichText").bool(enabled), null
+                Util.JS.callable("setRichText").bool(enabled), null
             );
         }
     }
@@ -223,14 +223,14 @@ public class Composer.WebView : ClientWebView {
      * Undoes the last edit operation.
      */
     public void undo() {
-        this.call.begin(Util.JS.callable("geary.undo"), null);
+        this.call_void.begin(Util.JS.callable("undo"), null);
     }
 
     /**
      * Redoes the last undone edit operation.
      */
     public void redo() {
-        this.call.begin(Util.JS.callable("geary.redo"), null);
+        this.call_void.begin(Util.JS.callable("redo"), null);
     }
 
     /**
@@ -239,9 +239,9 @@ public class Composer.WebView : ClientWebView {
      * Returns an id to be used to refer to the selection in
      * subsequent calls.
      */
-    public async string save_selection() throws Error {
+    public async string? save_selection() throws Error {
-        return Util.JS.to_string(
+        return yield call_returning<string?>(
-            yield call(Util.JS.callable("geary.saveSelection"), null)
+            Util.JS.callable("saveSelection"), null
         );
     }
 
@@ -249,9 +249,7 @@ public class Composer.WebView : ClientWebView {
      * Removes a saved selection.
      */
     public void free_selection(string id) {
-        this.call.begin(
+        this.call_void.begin(Util.JS.callable("freeSelection").string(id), null);
-            Util.JS.callable("geary.freeSelection").string(id), null
-        );
     }
 
     /**
@@ -357,9 +355,9 @@ public class Composer.WebView : ClientWebView {
      * will be inserted wrapping the selection.
      */
     public void insert_link(string href, string selection_id) {
-        this.call.begin(
+        this.call_void.begin(
             Util.JS.callable(
-                "geary.insertLink"
+                "insertLink"
             ).string(href).string(selection_id),
             null
         );
@@ -373,8 +371,8 @@ public class Composer.WebView : ClientWebView {
      * unlinked section.
      */
     public void delete_link(string selection_id) {
-        this.call.begin(
+        this.call_void.begin(
-            Util.JS.callable("geary.deleteLink").string(selection_id),
+            Util.JS.callable("deleteLink").string(selection_id),
             null
         );
     }
@@ -396,23 +394,23 @@ public class Composer.WebView : ClientWebView {
      * Indents the line at the current text cursor location.
      */
     public void indent_line() {
-        this.call.begin(Util.JS.callable("geary.indentLine"), null);
+        this.call_void.begin(Util.JS.callable("indentLine"), null);
     }
 
     public void insert_olist() {
-        this.call.begin(Util.JS.callable("geary.insertOrderedList"), null);
+        this.call_void.begin(Util.JS.callable("insertOrderedList"), null);
     }
 
     public void insert_ulist() {
-        this.call.begin(Util.JS.callable("geary.insertUnorderedList"), null);
+        this.call_void.begin(Util.JS.callable("insertUnorderedList"), null);
     }
 
     /**
      * Updates the signature block if it has not been deleted.
      */
     public new void update_signature(string signature) {
-        this.call.begin(
+        this.call_void.begin(
-            Util.JS.callable("geary.updateSignature").string(signature), null
+            Util.JS.callable("updateSignature").string(signature), null
         );
     }
 
@@ -420,22 +418,21 @@ public class Composer.WebView : ClientWebView {
      * Removes the quoted message (if any) from the composer.
      */
     public void delete_quoted_message() {
-        this.call.begin(Util.JS.callable("geary.deleteQuotedMessage"), null);
+        this.call_void.begin(Util.JS.callable("deleteQuotedMessage"), null);
     }
 
     /**
      * Determines if the editor content contains an attachment keyword.
      */
-    public async bool contains_attachment_keywords(string keyword_spec,
+    public async bool? contains_attachment_keywords(string keyword_spec,
-                                                   string subject) {
+                                                    string subject) {
         try {
-            return Util.JS.to_bool(
+            return yield call_returning<bool?>(
-                yield call(
+                Util.JS.callable("containsAttachmentKeyword")
-                    Util.JS.callable("geary.containsAttachmentKeyword")
+                .string(keyword_spec)
-                    .string(keyword_spec)
+                .string(subject),
-                    .string(subject),
+                null
-                    null)
+            );
-                );
         } catch (Error err) {
             debug("Error checking or attachment keywords: %s", err.message);
             return false;
@@ -449,7 +446,7 @@ public class Composer.WebView : ClientWebView {
      * this.
      */
     public async void clean_content() throws Error {
-        this.call.begin(Util.JS.callable("geary.cleanContent"), null);
+        this.call_void.begin(Util.JS.callable("cleanContent"), null);
     }
 
     /**
@@ -459,10 +456,10 @@ public class Composer.WebView : ClientWebView {
         const int MAX_BREAKABLE_LEN = 72; // F=F recommended line limit
         const int MAX_UNBREAKABLE_LEN = 998; // SMTP line limit
 
-        string body_text = Util.JS.to_string(
+        string? body_text = yield call_returning<string?>(
-            yield call(Util.JS.callable("geary.getText"), null)
+            Util.JS.callable("getText"), null
         );
-        string[] lines = body_text.split("\n");
+        string[] lines = (body_text ?? "").split("\n");
         GLib.StringBuilder flowed = new GLib.StringBuilder.sized(body_text.length);
         foreach (string line in lines) {
             // Strip trailing whitespace, so it doesn't look like a
@@ -533,50 +530,43 @@ public class Composer.WebView : ClientWebView {
         return ret;
     }
 
-    private void on_cursor_context_changed(WebKit.JavascriptResult result) {
+    private void on_cursor_context_changed(GLib.Variant? parameters) {
-        try {
+        if (parameters != null && parameters.classify() == STRING) {
-            cursor_context_changed(
+            cursor_context_changed(new EditContext(parameters as string));
-                new EditContext(Util.JS.to_string(result.get_js_value()))
+        } else {
-            );
+            warning("Could not get text cursor style");
-        } catch (Util.JS.Error err) {
-            debug("Could not get text cursor style: %s", err.message);
         }
     }
 
     /**
      *  Handle a dropped image
      */
-    private void on_drag_drop_received(WebKit.JavascriptResult result) {
+    private void on_drag_drop_received(GLib.Variant? parameters) {
+        var dict = new GLib.VariantDict(parameters);
+        string file_name = dict.lookup_value(
+            "fileName", GLib.VariantType.STRING
+        ).get_string();
+        string file_name_unescaped = GLib.Uri.unescape_string(file_name);
 
-        try {
+        string file_type = dict.lookup_value(
-            JSC.Value object = result.get_js_value();
+            "fileType", GLib.VariantType.STRING
-            string filename = Util.JS.to_string(
+        ).get_string();
-                Util.JS.get_property(object, "fileName")
-            );
-            string filename_unescaped = GLib.Uri.unescape_string(filename);
 
-            string file_type = Util.JS.to_string(
+        string content_base64 = dict.lookup_value(
-                Util.JS.get_property(object, "fileType")
+            "content", GLib.VariantType.STRING
-            );
+        ).get_string();
+        uint8[] image = GLib.Base64.decode(content_base64);
 
-            string content_base64 = Util.JS.to_string(
+        if (image.length == 0) {
-                Util.JS.get_property(object, "content")
+            warning("%s is empty", file_name);
-            );
+            return;
-            uint8[] image = GLib.Base64.decode(content_base64);
+        }
 
-            if (image.length == 0) {
+        // A simple check to see if the file looks like an image. A problem here
-                warning("%s is empty", filename);
+        // will be this accepting types which won't be supported by WebKit
-                return;
+        // or recipients.
-            }
+        if (file_type.index_of("image/") == 0) {
-
+            image_file_dropped(file_name_unescaped, file_type, image);
-            // A simple check to see if the file looks like an image. A problem here
-            // will be this accepting types which won't be supported by WebKit
-            // or recipients.
-            if (file_type.index_of("image/") == 0) {
-                image_file_dropped(filename_unescaped, file_type, image);
-            }
-        } catch (Util.JS.Error err) {
-            debug("Could not get deceptive link param: %s", err.message);
         }
     }
 }

src/client/composer/composer-widget.vala

@@ -1252,7 +1252,7 @@ public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {
         email.inline_files.set_all(this.inline_files);
         email.cid_files.set_all(this.cid_files);
 
-        email.img_src_prefix = ClientWebView.INTERNAL_URL_PREFIX;
+        email.img_src_prefix = Components.WebView.INTERNAL_URL_PREFIX;
 
         try {
             email.body_text = yield this.editor.body.get_text();
@@ -1450,15 +1450,16 @@ public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {
             confirmation = _("Send message with an empty subject?");
         } else if (!has_body && !has_attachment) {
             confirmation = _("Send message with an empty body?");
-        } else if (!has_attachment &&
+        } else if (!has_attachment) {
-                   yield this.editor.body.contains_attachment_keywords(
+            var keywords = string.join(
-                       string.join(
+                "|", ATTACHMENT_KEYWORDS, ATTACHMENT_KEYWORDS_LOCALISED
-                           "|",
+            );
-                           ATTACHMENT_KEYWORDS,
+            var contains = yield this.editor.body.contains_attachment_keywords(
-                           ATTACHMENT_KEYWORDS_LOCALISED
+                keywords, this.subject
-                       ),
+            );
-                       this.subject)) {
+            if (contains != null && contains) {
-            confirmation = _("Send message without an attachment?");
+                confirmation = _("Send message without an attachment?");
+            }
         }
         if (confirmation != null) {
             ConfirmationDialog dialog = new ConfirmationDialog(container.top_window,
@@ -1924,7 +1925,7 @@ public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {
                         string unique_filename;
                         add_inline_part(byte_buffer, filename, out unique_filename);
                         this.editor.body.insert_image(
-                            ClientWebView.INTERNAL_URL_PREFIX + unique_filename
+                            Components.WebView.INTERNAL_URL_PREFIX + unique_filename
                         );
                     } catch (Error error) {
                         this.application.report_problem(
@@ -1964,7 +1965,7 @@ public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {
                     string unique_filename;
                     add_inline_part(file_buffer, path, out unique_filename);
                     this.editor.body.insert_image(
-                        ClientWebView.INTERNAL_URL_PREFIX + unique_filename
+                        Components.WebView.INTERNAL_URL_PREFIX + unique_filename
                     );
                 } catch (Error err) {
                     attachment_failed(err.message);
@@ -2459,7 +2460,7 @@ public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {
         }
 
         this.editor.body.insert_image(
-            ClientWebView.INTERNAL_URL_PREFIX + unique_filename
+            Components.WebView.INTERNAL_URL_PREFIX + unique_filename
         );
     }
 

src/client/conversation-viewer/conversation-email.vala

@@ -462,7 +462,7 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
         if (this.body_selection_message != null) {
             try {
                 selection =
-                   yield this.body_selection_message.web_view.get_selection_for_quoting();
+                   yield this.body_selection_message.get_selection_for_quoting();
             } catch (Error err) {
                 debug("Failed to get selection for quoting: %s", err.message);
             }
@@ -478,7 +478,7 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
         if (this.body_selection_message != null) {
             try {
                 selection =
-                   yield this.body_selection_message.web_view.get_selection_for_find();
+                   yield this.body_selection_message.get_selection_for_find();
             } catch (Error err) {
                 debug("Failed to get selection for find: %s", err.message);
             }
@@ -571,12 +571,10 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
         Json.Generator generator = new Json.Generator();
         generator.set_root(builder.get_root());
         string js = "geary.addPrintHeaders(" + generator.to_data(null) + ");";
-        yield this.primary_message.web_view.run_javascript(js, null);
+        yield this.primary_message.run_javascript(js, null);
 
         Gtk.Window? window = get_toplevel() as Gtk.Window;
-        WebKit.PrintOperation op = new WebKit.PrintOperation(
+        WebKit.PrintOperation op = this.primary_message.new_print_operation();
-            this.primary_message.web_view
-        );
         Gtk.PrintSettings settings = new Gtk.PrintSettings();
 
         if (this.email.subject != null) {
@@ -603,14 +601,14 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
     }
 
     private void connect_message_view_signals(ConversationMessage view) {
+        view.content_loaded.connect(on_content_loaded);
         view.flag_remote_images.connect(on_flag_remote_images);
         view.internal_link_activated.connect((y) => {
                 internal_link_activated(y);
             });
+        view.internal_resource_loaded.connect(on_resource_loaded);
         view.save_image.connect(on_save_image);
-        view.web_view.internal_resource_loaded.connect(on_resource_loaded);
+        view.selection_changed.connect((has_selection) => {
-        view.web_view.content_loaded.connect(on_content_loaded);
-        view.web_view.selection_changed.connect((has_selection) => {
                 this.body_selection_message = has_selection ? view : null;
                 body_selection_changed(has_selection);
             });
@@ -686,7 +684,7 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
 
         // Load all messages
 
-        this.primary_message.web_view.add_internal_resources(cid_resources);
+        this.primary_message.add_internal_resources(cid_resources);
         yield this.primary_message.load_message_body(
             message, this.load_cancellable
         );
@@ -704,7 +702,7 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
                     this.config
                 );
             connect_message_view_signals(attached_message);
-            attached_message.web_view.add_internal_resources(cid_resources);
+            attached_message.add_internal_resources(cid_resources);
             this.sub_messages.add(attached_message);
             this._attached_messages.add(attached_message);
             attached_message.load_contacts.begin(this.load_cancellable);
@@ -886,8 +884,8 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
                                Geary.Memory.Buffer? content) {
         var main = get_toplevel() as Application.MainWindow;
         if (main != null) {
-            if (uri.has_prefix(ClientWebView.CID_URL_PREFIX)) {
+            if (uri.has_prefix(Components.WebView.CID_URL_PREFIX)) {
-                string cid = uri.substring(ClientWebView.CID_URL_PREFIX.length);
+                string cid = uri.substring(Components.WebView.CID_URL_PREFIX.length);
                 try {
                     Geary.Attachment attachment = this.email.get_attachment_by_content_id(
                         cid
@@ -934,7 +932,7 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
     private void on_content_loaded() {
         bool all_loaded = true;
         foreach (ConversationMessage message in this) {
-            if (!message.web_view.is_content_loaded) {
+            if (!message.is_content_loaded) {
                 all_loaded = false;
                 break;
             }

src/client/conversation-viewer/conversation-list-box.vala

@@ -957,7 +957,7 @@ public class ConversationListBox : Gtk.ListBox, Geary.BaseInterface {
      */
     public void zoom_in() {
         message_view_iterator().foreach((msg_view) => {
-                msg_view.web_view.zoom_in();
+                msg_view.zoom_in();
                 return true;
             });
     }
@@ -967,7 +967,7 @@ public class ConversationListBox : Gtk.ListBox, Geary.BaseInterface {
      */
     public void zoom_out() {
         message_view_iterator().foreach((msg_view) => {
-                msg_view.web_view.zoom_out();
+                msg_view.zoom_out();
                 return true;
             });
     }
@@ -977,7 +977,7 @@ public class ConversationListBox : Gtk.ListBox, Geary.BaseInterface {
      */
     public void zoom_reset() {
         message_view_iterator().foreach((msg_view) => {
-                msg_view.web_view.zoom_reset();
+                msg_view.zoom_reset();
                 return true;
             });
     }
@@ -1182,8 +1182,7 @@ public class ConversationListBox : Gtk.ListBox, Geary.BaseInterface {
         row.get_allocation(out alloc);
 
         int x = 0, y = 0;
-        ConversationWebView web_view = row.view.primary_message.web_view;
+        row.view.primary_message.web_view_translate_coordinates(row, x, anchor_y, out x, out y);
-        web_view.translate_coordinates(row, x, anchor_y, out x, out y);
 
         Gtk.Adjustment adj = get_adjustment();
         y = alloc.y + y;
@@ -1216,14 +1215,13 @@ public class ConversationListBox : Gtk.ListBox, Geary.BaseInterface {
                 ConversationMessage conversation_message = view.primary_message;
                  int body_top = 0;
                  int body_left = 0;
-                 ConversationWebView web_view = conversation_message.web_view;
+                 conversation_message.web_view_translate_coordinates(
-                 web_view.translate_coordinates(
                      this,
                      0, 0,
                      out body_left, out body_top
                  );
 
-                 int body_height = web_view.get_allocated_height();
+                 int body_height = conversation_message.web_view_get_allocated_height();
                  int body_bottom = body_top + body_height;
 
                  // Only mark the email as read if it's actually visible

src/client/conversation-viewer/conversation-message.vala

@@ -310,8 +310,19 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
     [GtkChild]
     internal Components.InfoBarStack info_bars;
 
+    /**
+     * Emitted when web_view's content has finished loaded.
+     *
+     * See {@link Components.WebView.is_content_loaded} for details.
+     */
+    internal bool is_content_loaded {
+        get {
+            return this.web_view != null && this.web_view.is_content_loaded;
+        }
+    }
+
     /** HTML view that displays the message body. */
-    internal ConversationWebView web_view { get; private set; }
+    private ConversationWebView? web_view { get; private set; }
 
     // The message headers represented by this view
     private Geary.EmailHeaderSet headers;
@@ -426,6 +437,19 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         string uri, string? alt_text, Geary.Memory.Buffer? buffer
     );
 
+    /** Emitted when web_view has loaded a resource added to it. */
+    public signal void internal_resource_loaded(string name);
+
+    /** Emitted when web_view's selection has changed. */
+    public signal void selection_changed(bool has_selection);
+
+    /**
+     * Emitted when web_view's content has finished loaded.
+     *
+     * See {@link Components.WebView.is_content_loaded} for details.
+     */
+    public signal void content_loaded();
+
 
     /**
      * Constructs a new view from an email's headers and body.
@@ -467,6 +491,18 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         );
     }
 
+    private void trigger_internal_resource_loaded(string name) {
+        internal_resource_loaded(name);
+    }
+
+    private void trigger_content_loaded() {
+        content_loaded();
+    }
+
+    private void trigger_selection_changed(bool has_selection) {
+        selection_changed(has_selection);
+    }
+
     private ConversationMessage(Geary.EmailHeaderSet headers,
                                 string? preview,
                                 bool load_remote_resources,
@@ -487,19 +523,10 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
             .activate.connect(on_copy_email_address);
         add_action(ACTION_COPY_LINK, true, VariantType.STRING)
             .activate.connect(on_copy_link);
-        add_action(ACTION_COPY_SELECTION, false).activate.connect(() => {
-                web_view.copy_clipboard();
-            });
-        add_action(ACTION_OPEN_INSPECTOR, config.enable_inspector).activate.connect(() => {
-                this.web_view.get_inspector().show();
-            });
         add_action(ACTION_OPEN_LINK, true, VariantType.STRING)
             .activate.connect(on_link_activated);
         add_action(ACTION_SAVE_IMAGE, true, new VariantType("(sms)"))
             .activate.connect(on_save_image);
-        add_action(ACTION_SELECT_ALL, true).activate.connect(() => {
-                web_view.select_all();
-            });
         insert_action_group("msg", message_actions);
 
         // Context menu
@@ -552,25 +579,7 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
             this.subject_searchable = headers.subject.value.casefold();
         }
 
-        // Web view
-
-        this.web_view = new ConversationWebView(config);
-        this.web_view.context_menu.connect(on_context_menu);
-        this.web_view.deceptive_link_clicked.connect(on_deceptive_link_clicked);
-        this.web_view.link_activated.connect((link) => {
-                on_link_activated(new GLib.Variant("s", link));
-            });
-        this.web_view.mouse_target_changed.connect(on_mouse_target_changed);
-        this.web_view.notify["is-loading"].connect(on_is_loading_notify);
-        this.web_view.resource_load_started.connect(on_resource_load_started);
-        this.web_view.remote_image_load_blocked.connect(on_remote_images_blocked);
-        this.web_view.selection_changed.connect(on_selection_changed);
-        this.web_view.set_hexpand(true);
-        this.web_view.set_vexpand(true);
-        this.web_view.show();
-
         this.body_container.set_has_tooltip(true); // Used to show link URLs
-        this.body_container.add(this.web_view);
         this.show_progress_timeout = new Geary.TimeoutManager.milliseconds(
             Util.Gtk.SHOW_PROGRESS_TIMEOUT_MSEC, this.on_show_progress_timeout
         );
@@ -584,6 +593,51 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         this.progress_pulse.repetition = FOREVER;
     }
 
+    private void initialize_web_view() {
+        var viewer = get_ancestor(typeof(ConversationViewer)) as ConversationViewer;
+
+        // Ensure we share the same WebProcess with the last one
+        // constructed if possible.
+        if (viewer != null && viewer.previous_web_view != null) {
+            this.web_view = new ConversationWebView.with_related_view(
+                this.config,
+                viewer.previous_web_view
+            );
+        } else {
+            this.web_view = new ConversationWebView(this.config);
+        }
+        if (viewer != null) {
+            viewer.previous_web_view = this.web_view;
+        }
+
+        this.web_view.context_menu.connect(on_context_menu);
+        this.web_view.deceptive_link_clicked.connect(on_deceptive_link_clicked);
+        this.web_view.link_activated.connect((link) => {
+                on_link_activated(new GLib.Variant("s", link));
+            });
+        this.web_view.mouse_target_changed.connect(on_mouse_target_changed);
+        this.web_view.notify["is-loading"].connect(on_is_loading_notify);
+        this.web_view.resource_load_started.connect(on_resource_load_started);
+        this.web_view.remote_image_load_blocked.connect(on_remote_images_blocked);
+        this.web_view.selection_changed.connect(on_selection_changed);
+        this.web_view.internal_resource_loaded.connect(trigger_internal_resource_loaded);
+        this.web_view.content_loaded.connect(trigger_content_loaded);
+        this.web_view.selection_changed.connect(trigger_selection_changed);
+        this.web_view.set_hexpand(true);
+        this.web_view.set_vexpand(true);
+        this.web_view.show();
+        this.body_container.add(this.web_view);
+        add_action(ACTION_COPY_SELECTION, false).activate.connect(() => {
+                web_view.copy_clipboard();
+            });
+        add_action(ACTION_OPEN_INSPECTOR, config.enable_inspector).activate.connect(() => {
+                this.web_view.get_inspector().show();
+            });
+        add_action(ACTION_SELECT_ALL, true).activate.connect(() => {
+                web_view.select_all();
+            });
+    }
+
     ~ConversationMessage() {
         base_unref();
     }
@@ -597,10 +651,77 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         base.destroy();
     }
 
+    public async string? get_selection_for_quoting() throws Error {
+        if (this.web_view == null)
+            initialize_web_view();
+        return yield web_view.get_selection_for_quoting();
+    }
+
+    public async string? get_selection_for_find() throws Error {
+        if (this.web_view == null)
+            initialize_web_view();
+        return yield web_view.get_selection_for_find();
+    }
+
+    /**
+     * Adds a set of internal resources to web_view.
+     *
+     * @see Components.WebView.add_internal_resources
+     */
+    public void add_internal_resources(Gee.Map<string,Geary.Memory.Buffer> res) {
+        if (this.web_view == null)
+            initialize_web_view();
+        web_view.add_internal_resources(res);
+    }
+
+    public WebKit.PrintOperation new_print_operation() {
+        if (this.web_view == null)
+            initialize_web_view();
+        return new WebKit.PrintOperation(web_view);
+    }
+
+    public async void run_javascript (string script, Cancellable? cancellable) throws Error {
+        if (this.web_view == null)
+            initialize_web_view();
+        yield web_view.run_javascript(script, cancellable);
+    }
+
+    public void zoom_in() {
+        if (this.web_view == null)
+            initialize_web_view();
+        web_view.zoom_in();
+    }
+
+    public void zoom_out() {
+        if (this.web_view == null)
+            initialize_web_view();
+        web_view.zoom_out();
+    }
+
+    public void zoom_reset() {
+        if (this.web_view == null)
+            initialize_web_view();
+        web_view.zoom_reset();
+    }
+
+    public void web_view_translate_coordinates(Gtk.Widget widget, int x, int anchor_y, out int x1, out int y1) {
+        if (this.web_view == null)
+            initialize_web_view();
+        web_view.translate_coordinates(widget, x, anchor_y, out x1, out y1);
+    }
+
+    public int web_view_get_allocated_height() {
+        if (this.web_view == null)
+            initialize_web_view();
+        return web_view.get_allocated_height();
+    }
+
     /**
      * Shows the complete message and hides the compact headers.
      */
     public void show_message_body(bool include_transitions=true) {
+        if (this.web_view == null)
+            initialize_web_view();
         set_revealer(this.compact_revealer, false, include_transitions);
         set_revealer(this.header_revealer, true, include_transitions);
         set_revealer(this.body_revealer, true, include_transitions);
@@ -785,6 +906,10 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
             throw new GLib.IOError.CANCELLED("Conversation load cancelled");
         }
 
+        if (this.web_view == null) {
+            initialize_web_view();
+        }
+
         bool contact_load_images = (
             this.primary_contact != null &&
             this.primary_contact.load_remote_resources
@@ -835,6 +960,8 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
             }
         }
 
+        if (this.web_view == null)
+            initialize_web_view();
         uint webkit_found = yield this.web_view.highlight_search_terms(
             search_matches, cancellable
         );
@@ -848,7 +975,9 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         foreach (ContactFlowBoxChild address in this.searchable_addresses) {
             address.unmark_search_terms();
         }
-        this.web_view.unmark_search_terms();
+
+        if (this.web_view != null)
+            this.web_view.unmark_search_terms();
     }
 
     /**
@@ -1011,6 +1140,8 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
     // returns HTML that is placed into the document in the position
     // where the MIME part was found
     private string? inline_image_replacer(Geary.RFC822.Part part) {
+        if (this.web_view == null)
+            initialize_web_view();
         Geary.Mime.ContentType content_type = part.content_type;
         if (content_type.media_type != "image" ||
             !this.web_view.can_show_mime_type(content_type.to_string())) {
@@ -1045,7 +1176,7 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         return "<img alt=\"%s\" class=\"%s\" src=\"%s%s\" />".printf(
             clean_filename,
             REPLACED_IMAGE_CLASS,
-            ClientWebView.CID_URL_PREFIX,
+            Components.WebView.CID_URL_PREFIX,
             Geary.HTML.escape_markup(id)
         );
     }
@@ -1059,7 +1190,9 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         this.load_remote_resources = true;
         this.remote_resources_requested = 0;
         this.remote_resources_loaded = 0;
-        this.web_view.load_remote_images();
+        if (this.web_view != null) {
+            this.web_view.load_remote_images();
+        }
         if (update_email_flag) {
             flag_remote_images();
         }
@@ -1074,11 +1207,13 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
 
         if (placeholder != null) {
             this.body_placeholder = placeholder;
-            this.web_view.hide();
+            if (this.web_view != null)
+                this.web_view.hide();
             this.body_container.add(placeholder);
             show_message_body(true);
         } else {
-            this.web_view.show();
+            if (this.web_view != null)
+                this.web_view.show();
         }
     }
 
@@ -1106,10 +1241,12 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
     }
 
     private void on_is_loading_notify() {
-        if (this.web_view.is_loading) {
+        if (this.web_view != null) {
-            start_progress_loading();
+            if (this.web_view.is_loading) {
-        } else {
+                start_progress_loading();
-            stop_progress_loading();
+            } else {
+                stop_progress_loading();
+            }
         }
     }
 
@@ -1369,7 +1506,7 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
             alt_text = (string) alt_maybe;
         }
 
-        if (uri.has_prefix(ClientWebView.CID_URL_PREFIX)) {
+        if (uri.has_prefix(Components.WebView.CID_URL_PREFIX)) {
             // We can get the data directly from the attachment, so
             // don't bother getting it from the web view
             save_image(uri, alt_text, null);

src/client/conversation-viewer/conversation-viewer.vala

@@ -24,6 +24,14 @@ public class ConversationViewer : Gtk.Stack, Geary.BaseInterface {
         get; private set; default = null;
     }
 
+    /**
+     * The most recent web view created in this viewer.
+     *
+     * Keep the last created web view around so others can share the
+     * same WebKitGTK WebProcess.
+     */
+    internal ConversationWebView? previous_web_view { get; set; default = null; }
+
     private Application.Configuration config;
 
     private Gee.Set<Geary.App.Conversation>? selection_while_composing = null;
@@ -251,7 +259,10 @@ public class ConversationViewer : Gtk.Stack, Geary.BaseInterface {
                                         Application.ContactStore contacts,
                                         bool start_mark_timer)
         throws GLib.Error {
-        remove_current_list();
+        // Keep the old ScrolledWindow around long enough for its
+        // descendant web views to be kept so their WebProcess can be
+        // re-used.
+        var old_scroller = remove_current_list();
 
         ConversationListBox new_list = new ConversationListBox(
             conversation,
@@ -297,6 +308,9 @@ public class ConversationViewer : Gtk.Stack, Geary.BaseInterface {
         }
 
         yield new_list.load_conversation(scroll_to, query);
+
+        // Not strictly necessary, but keeps the compiler happy
+        old_scroller.destroy();
     }
 
     // Add a new conversation list to the UI
@@ -316,7 +330,7 @@ public class ConversationViewer : Gtk.Stack, Geary.BaseInterface {
     }
 
     // Remove any existing conversation list, cancelling its loading
-    private void remove_current_list() {
+    private Gtk.ScrolledWindow remove_current_list() {
         if (this.find_cancellable != null) {
             this.find_cancellable.cancel();
             this.find_cancellable = null;
@@ -328,15 +342,17 @@ public class ConversationViewer : Gtk.Stack, Geary.BaseInterface {
             this.current_list = null;
         }
 
+        var old_scroller = this.conversation_scroller;
         // XXX GTK+ Bug 778190 workaround
-        this.conversation_scroller.destroy(); // removes the list
+        this.conversation_page.remove(old_scroller);
         new_conversation_scroller();
+        return old_scroller;
     }
 
     private void new_conversation_scroller() {
         // XXX Work around for GTK+ Bug 778190: Instead of replacing
         // the Viewport that contains the current list, replace the
-        // complete ScrolledWindow. Need to put remove this method and
+        // complete ScrolledWindow. Need to remove this method and
         // put the settings back into conversation-viewer.ui when we
         // can rely on it being fixed again.
         Gtk.ScrolledWindow scroller = new Gtk.ScrolledWindow(null, null);

src/client/conversation-viewer/conversation-web-view.vala

@@ -1,15 +1,15 @@
 /*
- * Copyright 2016 Software Freedom Conservancy Inc.
+ * Copyright © 2016 Software Freedom Conservancy Inc.
- * Copyright 2017 Michael Gratton <mike@vee.net>
+ * Copyright © 2017-2020 Michael Gratton <mike@vee.net>
  *
  * This software is licensed under the GNU Lesser General Public License
  * (version 2.1 or later).  See the COPYING file in this distribution.
  */
 
-public class ConversationWebView : ClientWebView {
+public class ConversationWebView : Components.WebView {
 
 
-    private const string DECEPTIVE_LINK_CLICKED = "deceptiveLinkClicked";
+    private const string DECEPTIVE_LINK_CLICKED = "deceptive_link_clicked";
 
     // Key codes we don't forward on to the super class on key press
     // since we want to override them elsewhere, especially
@@ -41,10 +41,10 @@ public class ConversationWebView : ClientWebView {
 
     public static new void load_resources()
         throws Error {
-        ConversationWebView.app_script = ClientWebView.load_app_script(
+        ConversationWebView.app_script = Components.WebView.load_app_script(
             "conversation-web-view.js"
         );
-        ConversationWebView.app_stylesheet = ClientWebView.load_app_stylesheet(
+        ConversationWebView.app_stylesheet = Components.WebView.load_app_stylesheet(
             "conversation-web-view.css"
         );
     }
@@ -56,36 +56,51 @@ public class ConversationWebView : ClientWebView {
     );
 
 
+    /**
+     * Constructs a new web view for displaying an email message body.
+     *
+     * A new WebKitGTK WebProcess will be constructed for this view.
+     */
     public ConversationWebView(Application.Configuration config) {
         base(config);
+        init();
+
+        // These only need to be added when creating a new WebProcess,
+        // not when sharing one
         this.user_content_manager.add_script(ConversationWebView.app_script);
         this.user_content_manager.add_style_sheet(ConversationWebView.app_stylesheet);
+    }
 
-        register_message_handler(
+    /**
-            DECEPTIVE_LINK_CLICKED, on_deceptive_link_clicked
+     * Constructs a new web view for displaying an email message body.
-        );
+     *
-
+     * The WebKitGTK WebProcess will be shared with the related view's
-        this.notify["preferred-height"].connect(() => queue_resize());
+     * process.
+     */
+    internal ConversationWebView.with_related_view(
+        Application.Configuration config,
+        ConversationWebView related
+    ) {
+        base.with_related_view(config, related);
+        init();
     }
 
     /**
      * Returns the current selection, for prefill as find text.
      */
     public async string? get_selection_for_find() throws Error{
-        JSC.Value result = yield call(
+        return yield call_returning<string?>(
-            Util.JS.callable("geary.getSelectionForFind"), null
+            Util.JS.callable("getSelectionForFind"), null
         );
-        return Util.JS.to_string(result);
     }
 
     /**
      * Returns the current selection, for quoting in a message.
      */
     public async string? get_selection_for_quoting() throws Error {
-        JSC.Value result = yield call(
+        return yield call_returning<string?>(
-            Util.JS.callable("geary.getSelectionForQuoting"), null
+            Util.JS.callable("getSelectionForQuoting"), null
         );
-        return Util.JS.to_string(result);
     }
 
     /**
@@ -93,10 +108,9 @@ public class ConversationWebView : ClientWebView {
      */
     public async int? get_anchor_target_y(string anchor_body)
         throws GLib.Error {
-        JSC.Value result = yield call(
+        return yield call_returning<int?>(
-            Util.JS.callable("geary.getAnchorTargetY").string(anchor_body), null
+            Util.JS.callable("getAnchorTargetY").string(anchor_body), null
         );
-        return (int) Util.JS.to_int32(result);
     }
 
     /**
@@ -206,41 +220,48 @@ public class ConversationWebView : ClientWebView {
         minimum_height = natural_height = 0;
     }
 
-    private void on_deceptive_link_clicked(WebKit.JavascriptResult result) {
+    private void init() {
-        try {
+        register_message_callback(
-            JSC.Value object = result.get_js_value();
+            DECEPTIVE_LINK_CLICKED, on_deceptive_link_clicked
-            uint reason = (uint) Util.JS.to_int32(
+        );
-                Util.JS.get_property(object, "reason")
-            );
 
-            string href = Util.JS.to_string(
+        this.notify["preferred-height"].connect(() => queue_resize());
-                Util.JS.get_property(object, "href")
+    }
-            );
 
-            string text = Util.JS.to_string(
+    private void on_deceptive_link_clicked(GLib.Variant? parameters) {
-                Util.JS.get_property(object, "text")
+        var dict = new GLib.VariantDict(parameters);
-            );
+        uint reason = (uint) dict.lookup_value(
+            "reason", GLib.VariantType.DOUBLE
+        ).get_double();
 
-            JSC.Value js_location = Util.JS.get_property(object, "location");
+        string href = dict.lookup_value(
+            "href", GLib.VariantType.STRING
+        ).get_string();
 
-            Gdk.Rectangle location = Gdk.Rectangle();
+        string text = dict.lookup_value(
-            location.x = Util.JS.to_int32(
+            "text", GLib.VariantType.STRING
-                Util.JS.get_property(js_location, "x")
+        ).get_string();
-            );
-            location.y = Util.JS.to_int32(
-                Util.JS.get_property(js_location, "y")
-            );
-            location.width = Util.JS.to_int32(
-                Util.JS.get_property(js_location, "width")
-            );
-            location.height = Util.JS.to_int32(
-                Util.JS.get_property(js_location, "height")
-            );
 
-            deceptive_link_clicked((DeceptiveText) reason, text, href, location);
+        Gdk.Rectangle location = Gdk.Rectangle();
-        } catch (Util.JS.Error err) {
+        var location_dict = new GLib.VariantDict(
-            debug("Could not get deceptive link param: %s", err.message);
+            dict.lookup_value("location", GLib.VariantType.VARDICT)
-        }
+        );
+        location.x = (int) location_dict.lookup_value(
+            "x", GLib.VariantType.DOUBLE
+        ).get_double();
+        location.y = (int) location_dict.lookup_value(
+            "y", GLib.VariantType.DOUBLE
+        ).get_double();
+        location.width = (int) location_dict.lookup_value(
+            "width", GLib.VariantType.DOUBLE
+        ).get_double();
+        location.height = (int) location_dict.lookup_value(
+            "height", GLib.VariantType.DOUBLE
+        ).get_double();
+
+        deceptive_link_clicked(
+            (DeceptiveText) reason, text, href, location
+        );
     }
 
 }

src/client/meson.build

@@ -46,7 +46,6 @@ client_vala_sources = files(
 
   'client-action.vala',
 
-  'components/client-web-view.vala',
   'components/components-attachment-pane.vala',
   'components/components-conversation-actions.vala',
   'components/components-conversation-action-bar.vala',
@@ -64,6 +63,7 @@ client_vala_sources = files(
   'components/components-reflow-box.c',
   'components/components-search-bar.vala',
   'components/components-validator.vala',
+  'components/components-web-view.vala',
   'components/count-badge.vala',
   'components/folder-popover.vala',
   'components/icon-factory.vala',
@@ -191,16 +191,6 @@ client_vala_args += [
   )
 ]
 
-# Enable shared shecondary process if available.
-# See issues #558 and #559
-webkit_version = webkit2gtk.version().split('.')
-if webkit_version[0].to_int() <= 2 and webkit_version[1].to_int() <= 24
-  message('Enabling WebKitGTK shared process model')
-  client_vala_args += [
-    '-D', 'HAS_WEBKIT_SHARED_PROC'
-  ]
-endif
-
 # Main client application library
 client_lib = shared_library(
   client_package,

src/client/util/util-js.vala

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017,2019 Michael James Gratton <mike@vee.net>
+ * Copyright © 2017-2020 Michael Gratton <mike@vee.net>
  *
  * This software is licensed under the GNU Lesser General Public License
  * (version 2.1 or later). See the COPYING file in this distribution.
@@ -25,6 +25,64 @@ namespace Util.JS {
         TYPE
     }
 
+    /** Supported types of JSC values. */
+    public enum JscType {
+
+        /** Specifies an unsupported value type. */
+        UNKNOWN,
+
+        /** Specifies a JavaScript `undefined` value. */
+        UNDEFINED,
+
+        /** Specifies a JavaScript `null` value. */
+        NULL,
+        FUNCTION,
+        STRING,
+        NUMBER,
+        BOOLEAN,
+        ARRAY,
+        CONSTRUCTOR,
+        OBJECT;
+
+        /**
+         * Determines the type of a JSC value.
+         *
+         * Returns the type of the given value, or {@link UNKNOWN} if
+         * it could not be determined.
+         */
+        public static JscType to_type(JSC.Value value) {
+            if (value.is_undefined()) {
+                return UNDEFINED;
+            }
+            if (value.is_null()) {
+                return NULL;
+            }
+            if (value.is_string()) {
+                return STRING;
+            }
+            if (value.is_number()) {
+                return NUMBER;
+            }
+            if (value.is_boolean()) {
+                return BOOLEAN;
+            }
+            if (value.is_array()) {
+                return ARRAY;
+            }
+            if (value.is_object()) {
+                return OBJECT;
+            }
+            if (value.is_function()) {
+                return FUNCTION;
+            }
+            if (value.is_constructor()) {
+                return CONSTRUCTOR;
+            }
+            return UNKNOWN;
+        }
+
+    }
+
     /**
      * Returns a JSC Value as a bool.
      *
@@ -128,53 +186,182 @@ namespace Util.JS {
     }
 
     /**
-     * Escapes a string so as to be safe to use as a JS string literal.
+     * Converts a JS value to a GLib variant.
      *
-     * This does not append opening or closing quotes.
+     * Simple value objects (string, number, and Boolean values),
+     * arrays of these, and objects with these types as properties are
+     * supported. Arrays containing objects of the same type are
+     * converted to arrays, otherwise they are converted to tuples,
+     * empty arrays are converted to the unit tuple, and objects are
+     * converted to vardict containing property names as keys and
+     * values. Null and undefined values are returned as an empty
+     * maybe variant type, since it is not possible to determine the
+     * actual type.
+     *
+     * Throws a type error if the given value's type is not supported.
      */
-    public string escape_string(string value) {
+    public inline GLib.Variant value_to_variant(JSC.Value value)
-        StringBuilder builder = new StringBuilder.sized(value.length);
+        throws Error {
-        for (int i = 0; i < value.length; i++) {
+        GLib.Variant? variant = null;
-            if (value.valid_char(i)) {
+        switch (JscType.to_type(value)) {
-                unichar c = value.get_char(i);
+        case UNDEFINED:
-                switch (c) {
+        case NULL:
-                case '\x00':
+            variant = new GLib.Variant.maybe(GLib.VariantType.VARIANT, null);
-                    builder.append("\x00");
+            break;
-                    break;
+
-                case '\'':
+        case STRING:
-                    builder.append("\\\'");
+            variant = new GLib.Variant.string(value.to_string());
-                    break;
+            break;
-                case '"':
+
-                    builder.append("\\\"");
+        case NUMBER:
-                    break;
+            variant = new GLib.Variant.double(value.to_double());
-                case '\\':
+            break;
-                    builder.append("\\\\");
+
-                    break;
+        case BOOLEAN:
-                case '\n':
+            variant = new GLib.Variant.boolean(value.to_boolean());
-                    builder.append("\\n");
+            break;
-                    break;
+
-                case '\r':
+        case ARRAY:
-                    builder.append("\\r");
+            int len = to_int32(value.object_get_property("length"));
-                    break;
+            if (len == 0) {
-                case '\x0b':
+                variant = new GLib.Variant.tuple({});
-                    builder.append("\x0b");
+            } else {
-                    break;
+                JSC.Value element = value.object_get_property_at_index(0);
-                case '\t':
+                var first_type = JscType.to_type(element);
-                    builder.append("\\t");
+                var all_same_type = true;
-                    break;
+                var values = new GLib.Variant[len];
-                case '\b':
+                values[0] = value_to_variant(element);
-                    builder.append("\\b");
+                for (int i = 1; i < len; i++) {
-                    break;
+                    element = value.object_get_property_at_index(i);
-                case '\f':
+                    values[i] = value_to_variant(element);
-                    builder.append("\\f");
+                    all_same_type &= (first_type == JscType.to_type(element));
-                    break;
+                }
-                default:
+                if (!all_same_type) {
-                    builder.append_unichar(c);
+                    variant = new GLib.Variant.tuple(values);
-                    break;
+                } else {
+                    variant = new GLib.Variant.array(
+                        values[0].get_type(), values
+                    );
+                }
+            }
+            break;
+
+        case OBJECT:
+            GLib.VariantDict dict = new GLib.VariantDict();
+            string[] names = value.object_enumerate_properties();
+            if (names != null) {
+                foreach (var name in names) {
+                    dict.insert_value(
+                        name,
+                        value_to_variant(value.object_get_property(name))
+                    );
+                }
+            }
+            variant = dict.end();
+            break;
+
+        default:
+            throw new Error.TYPE("Unsupported JS type: %s", value.to_string());
+        }
+        return variant;
+    }
+
+    /**
+     * Converts a GLib variant to a JS value.
+     *
+     * Simple value objects (string, number, and Boolean values),
+     * arrays and tuples of these, and dictionaries with string keys
+     * are supported. Tuples and arrays are converted to JS arrays,
+     * and dictionaries or tuples containing dictionary entries are
+     * converted to JS objects.
+     *
+     * Throws a type error if the given variant's type is not supported.
+     */
+    public inline JSC.Value variant_to_value(JSC.Context context,
+                                             GLib.Variant variant)
+        throws Error.TYPE {
+        JSC.Value? value = null;
+        GLib.Variant.Class type = variant.classify();
+        if (type == MAYBE) {
+            GLib.Variant? maybe = variant.get_maybe();
+            if (maybe != null) {
+                value = variant_to_value(context, maybe);
+            } else {
+                value = new JSC.Value.null(context);
+            }
+        } else if (type == VARIANT) {
+            value = variant_to_value(context, variant.get_variant());
+        } else if (type == STRING) {
+            value = new JSC.Value.string(context, variant.get_string());
+        } else if (type == BOOLEAN) {
+            value = new JSC.Value.boolean(context, variant.get_boolean());
+        } else if (type == DOUBLE) {
+            value = new JSC.Value.number(context, variant.get_double());
+        } else if (type == INT64) {
+            value = new JSC.Value.number(context, (double) variant.get_int64());
+        } else if (type == INT32) {
+            value = new JSC.Value.number(context, (double) variant.get_int32());
+        } else if (type == INT16) {
+            value = new JSC.Value.number(context, (double) variant.get_int16());
+        } else if (type == UINT64) {
+            value = new JSC.Value.number(context, (double) variant.get_uint64());
+        } else if (type == UINT32) {
+            value = new JSC.Value.number(context, (double) variant.get_uint32());
+        } else if (type == UINT16) {
+            value = new JSC.Value.number(context, (double) variant.get_uint16());
+        } else if (type == BYTE) {
+            value = new JSC.Value.number(context, (double) variant.get_byte());
+        } else if (type == ARRAY ||
+                   type == TUPLE) {
+            size_t len = variant.n_children();
+            if (len == 0) {
+                if (type == ARRAY ||
+                    type == TUPLE) {
+                    value = new JSC.Value.array_from_garray(context, null);
+                } else {
+                    value = new JSC.Value.object(context, null, null);
+                }
+            } else {
+                var first = variant.get_child_value(0);
+                if (first.classify() == DICT_ENTRY) {
+                    value = new JSC.Value.object(context, null, null);
+                    for (size_t i = 0; i < len; i++) {
+                        var entry = variant.get_child_value(i);
+                        if (entry.classify() != DICT_ENTRY) {
+                            throw new Error.TYPE(
+                                "Variant mixes dict entries with others: %s",
+                                variant.print(true)
+                            );
+                        }
+                        var key = entry.get_child_value(0);
+                        if (key.classify() != STRING) {
+                            throw new Error.TYPE(
+                                "Dict entry key is not a string: %s",
+                                entry.print(true)
+                            );
+                        }
+                        value.object_set_property(
+                            key.get_string(),
+                            variant_to_value(context, entry.get_child_value(1))
+                        );
+                    }
+                } else {
+                    var values = new GLib.GenericArray<JSC.Value>((uint) len);
+                    for (size_t i = 0; i < len; i++) {
+                        values.add(
+                            variant_to_value(context, variant.get_child_value(i))
+                        );
+                    }
+                    value = new JSC.Value.array_from_garray(context, values);
                 }
             }
         }
-        return (string) builder.data;
+        if (value == null) {
+            throw new Error.TYPE(
+                "Unsupported variant type %s", variant.print(true)
+            );
+        }
+        return value;
     }
 
     /**
@@ -189,40 +376,54 @@ namespace Util.JS {
      */
     public class Callable {
 
-        private string base_name;
+        private string name;
-        private string[] safe_args = new string[0];
+        private GLib.Variant[] args = {};
 
 
-        public Callable(string base_name) {
+        public Callable(string name) {
-            this.base_name = base_name;
+            this.name = name;
+        }
+
+        public WebKit.UserMessage to_message() {
+            GLib.Variant? args = null;
+            if (this.args.length == 1) {
+                args = this.args[0];
+            } else if (this.args.length > 1) {
+                args = new GLib.Variant.tuple(this.args);
+            }
+            return new WebKit.UserMessage(this.name, args);
         }
 
         public string to_string() {
-            return base_name + "(" + global::string.joinv(",", safe_args) + ");";
+            string[] args = new string[this.args.length];
+            for (int i = 0; i < args.length; i++) {
+                args[i] = this.args[i].print(true);
+            }
+            return this.name + "(" + global::string.joinv(",", args) + ")";
         }
 
         public Callable string(string value) {
-            add_param("\"" + escape_string(value) + "\"");
+            add_param(new GLib.Variant.string(value));
             return this;
         }
 
         public Callable double(double value) {
-            add_param(value.to_string());
+            add_param(new GLib.Variant.double(value));
             return this;
         }
 
         public Callable int(int value) {
-            add_param(value.to_string());
+            add_param(new GLib.Variant.int32(value));
             return this;
         }
 
         public Callable bool(bool value) {
-            add_param(value ? "true" : "false");
+            add_param(new GLib.Variant.boolean(value));
             return this;
         }
 
-        private inline void add_param(string value) {
+        private inline void add_param(GLib.Variant value) {
-            this.safe_args += value;
+            this.args += value;
         }
 
     }

src/client/web-process/web-process-extension.vala

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Michael Gratton <mike@vee.net>
+ * Copyright © 2016-2020 Michael Gratton <mike@vee.net>
  *
  * This software is licensed under the GNU Lesser General Public License
  * (version 2.1 or later). See the COPYING file in this distribution.
@@ -13,9 +13,9 @@ public void webkit_web_extension_initialize_with_user_data(WebKit.WebExtension e
     bool logging_enabled = data.get_boolean();
 
     Geary.Logging.init();
-    GLib.Log.set_writer_func(Geary.Logging.default_log_writer);
     if (logging_enabled) {
-        Geary.Logging.log_to(stdout);
+        GLib.Log.set_writer_func(Geary.Logging.default_log_writer);
+        Geary.Logging.log_to(GLib.stdout);
     }
 
     debug("Initialising...");
@@ -30,27 +30,26 @@ public void webkit_web_extension_initialize_with_user_data(WebKit.WebExtension e
  */
 public class GearyWebExtension : Object {
 
+    private const string PAGE_STATE_OBJECT_NAME = "geary";
+
+    // Keep these in sync with Components.WebView
+    private const string MESSAGE_RETURN_VALUE_NAME = "__return__";
+    private const string MESSAGE_EXCEPTION_NAME = "__exception__";
+
     private const string[] ALLOWED_SCHEMES = { "cid", "geary", "data", "blob" };
 
+    private const string EXTENSION_CLASS_VAR = "_GearyWebExtension";
+    private const string EXTENSION_CLASS_SEND = "send";
+    private const string REMOTE_LOAD_VAR = "_gearyAllowRemoteResourceLoads";
+
     private WebKit.WebExtension extension;
 
 
     public GearyWebExtension(WebKit.WebExtension extension) {
         this.extension = extension;
-        extension.page_created.connect((extension, web_page) => {
+        extension.page_created.connect(on_page_created);
-                web_page.console_message_sent.connect(on_console_message);
-                web_page.send_request.connect(on_send_request);
-                // XXX investigate whether the earliest supported
-                // version of WK supports the DOM "selectionchanged"
-                // event, and if so use that rather that doing it in
-                // here in the extension
-                web_page.get_editor().selection_changed.connect(() => {
-                    selection_changed(web_page);
-                });
-            });
     }
 
-    // XXX Conditionally enable while we still depend on WK2 <2.12
     private void on_console_message(WebKit.WebPage page,
                                     WebKit.ConsoleMessage message) {
         string source = message.get_source_id();
@@ -77,7 +76,10 @@ public class GearyWebExtension : Object {
             if (should_load_remote_images(page)) {
                 should_load = true;
             } else {
-                remote_image_load_blocked(page);
+                page.send_message_to_view.begin(
+                    new WebKit.UserMessage("remote_image_load_blocked", null),
+                    null
+                );
             }
         }
 
@@ -89,14 +91,7 @@ public class GearyWebExtension : Object {
         WebKit.Frame frame = page.get_main_frame();
         JSC.Context context = frame.get_js_context();
         try {
-            JSC.Value ret = execute_script(
+            should_load = Util.JS.to_bool(context.get_value(REMOTE_LOAD_VAR));
-                context,
-                "geary.allowRemoteImages",
-                GLib.Log.FILE,
-                GLib.Log.METHOD,
-                GLib.Log.LINE
-            );
-            should_load = Util.JS.to_bool(ret);
         } catch (GLib.Error err) {
             debug(
                 "Error checking PageState::allowRemoteImages: %s",
@@ -106,52 +101,172 @@ public class GearyWebExtension : Object {
         return should_load;
     }
 
-    private void remote_image_load_blocked(WebKit.WebPage page) {
+    private WebKit.UserMessage to_exception_message(string? name,
-        WebKit.Frame frame = page.get_main_frame();
+                                                    string? message,
-        JSC.Context context = frame.get_js_context();
+                                                    string? backtrace = null,
-        try {
+                                                    string? source = null,
-            execute_script(
+                                                    int line_number = -1,
-                context,
+                                                    int column_number = -1) {
-                "geary.remoteImageLoadBlocked();",
+        var detail = new GLib.VariantDict();
-                GLib.Log.FILE,
+        if (name != null) {
-                GLib.Log.METHOD,
+            detail.insert_value("name", new GLib.Variant.string(name));
-                GLib.Log.LINE
-            );
-        } catch (Error err) {
-            debug(
-                "Error calling PageState::remoteImageLoadBlocked: %s",
-                err.message
-            );
         }
-    }
+        if (message != null) {
-
+            detail.insert_value("message", new GLib.Variant.string(message));
-    private void selection_changed(WebKit.WebPage page) {
-        WebKit.Frame frame = page.get_main_frame();
-        JSC.Context context = frame.get_js_context();
-        try {
-            execute_script(
-                context,
-                "geary.selectionChanged();",
-                GLib.Log.FILE,
-                GLib.Log.METHOD,
-                GLib.Log.LINE
-            );
-        } catch (Error err) {
-            debug("Error calling PageStates::selectionChanged: %s", err.message);
         }
-    }
+        if (backtrace != null) {
-
+            detail.insert_value("backtrace", new GLib.Variant.string(backtrace));
-    private JSC.Value execute_script(JSC.Context context,
+        }
-                                     string script,
+        if (source != null) {
-                                     string file_name,
+            detail.insert_value("source", new GLib.Variant.string(source));
-                                     string method_name,
+        }
-                                     int line_number)
+        if (line_number > 0) {
-        throws Util.JS.Error {
+            detail.insert_value("line_number", new GLib.Variant.uint32(line_number));
-        JSC.Value ret = context.evaluate_with_source_uri(
+        }
-            script, -1, "geary:%s/%s".printf(file_name, method_name), line_number
+        if (column_number > 0) {
+            detail.insert_value("column_number", new GLib.Variant.uint32(column_number));
+        }
+        return new WebKit.UserMessage(
+            MESSAGE_EXCEPTION_NAME,
+            detail.end()
         );
-        Util.JS.check_exception(context);
+    }
-        return ret;
+
+    private void on_page_created(WebKit.WebExtension extension,
+                                 WebKit.WebPage page) {
+        WebKit.Frame frame = page.get_main_frame();
+        JSC.Context context = frame.get_js_context();
+
+        var extension_class = context.register_class(
+            this.get_type().name(),
+            null,
+            null,
+            null
+        );
+        extension_class.add_method(
+            EXTENSION_CLASS_SEND,
+            (instance, values) => {
+                return this.on_page_send_message(page, values);
+            },
+            GLib.Type.NONE
+        );
+        context.set_value(
+            EXTENSION_CLASS_VAR,
+            new JSC.Value.object(context, extension_class, extension_class)
+        );
+
+        context.set_value(
+            REMOTE_LOAD_VAR,
+            new JSC.Value.boolean(context, false)
+        );
+
+        page.console_message_sent.connect(on_console_message);
+        page.send_request.connect(on_send_request);
+        page.user_message_received.connect(on_page_message_received);
+    }
+
+    private bool on_page_message_received(WebKit.WebPage page,
+                                          WebKit.UserMessage message) {
+        WebKit.Frame frame = page.get_main_frame();
+        JSC.Context context = frame.get_js_context();
+        JSC.Value page_state = context.get_value(PAGE_STATE_OBJECT_NAME);
+
+        try {
+            JSC.Value[]? call_param = null;
+            GLib.Variant? message_param = message.parameters;
+            if (message_param != null) {
+                if (message_param.is_container()) {
+                    size_t len = message_param.n_children();
+                    call_param = new JSC.Value[len];
+                    for (size_t i = 0; i < len; i++) {
+                        call_param[i] = Util.JS.variant_to_value(
+                            context,
+                            message_param.get_child_value(i)
+                        );
+                    }
+                } else {
+                    call_param = {
+                        Util.JS.variant_to_value(context, message_param)
+                    };
+                }
+            }
+
+            JSC.Value ret = page_state.object_invoke_methodv(
+                message.name, call_param
+            );
+
+            // Must send a reply, even for void calls, otherwise
+            // WebKitGTK will complain. So return a message return
+            // rain hail or shine.
+            // https://bugs.webkit.org/show_bug.cgi?id=215880
+
+            JSC.Exception? thrown = context.get_exception();
+            if (thrown != null) {
+                message.send_reply(
+                    to_exception_message(
+                        thrown.get_name(),
+                        thrown.get_message(),
+                        thrown.get_backtrace_string(),
+                        thrown.get_source_uri(),
+                        (int) thrown.get_line_number(),
+                        (int) thrown.get_column_number()
+                    )
+                );
+            } else {
+                message.send_reply(
+                    new WebKit.UserMessage(
+                        MESSAGE_RETURN_VALUE_NAME,
+                        Util.JS.value_to_variant(ret)
+                    )
+                );
+            }
+        } catch (GLib.Error err) {
+            debug("Failed to handle message: %s", err.message);
+        }
+
+        return true;
+    }
+
+    private bool on_page_send_message(WebKit.WebPage page,
+                                      GLib.GenericArray<JSC.Value> args) {
+        WebKit.UserMessage? message = null;
+        if (args.length > 0) {
+            var name = args.get(0).to_string();
+            GLib.Variant? parameters = null;
+            if (args.length > 1) {
+                JSC.Value param_value = args.get(1);
+                try {
+                    int len = Util.JS.to_int32(
+                        param_value.object_get_property("length")
+                    );
+                    if (len == 1) {
+                        parameters = Util.JS.value_to_variant(
+                            param_value.object_get_property_at_index(0)
+                        );
+                    } else if (len > 1) {
+                        parameters = Util.JS.value_to_variant(param_value);
+                    }
+                } catch (Util.JS.Error err) {
+                    message = to_exception_message(
+                        this.get_type().name(), err.message
+                    );
+                }
+            }
+            if (message == null) {
+                message = new WebKit.UserMessage(name, parameters);
+            }
+        }
+        if (message == null) {
+            var log_message = "Not enough parameters for JS call to %s.%s()".printf(
+                EXTENSION_CLASS_VAR,
+                EXTENSION_CLASS_SEND
+            );
+            debug(log_message);
+            message = to_exception_message(this.get_type().name(), log_message);
+        }
+
+        page.send_message_to_view.begin(message, null);
+        return true;
     }
 
 }

test/client/components/components-web-view-test-case.vala

@@ -6,35 +6,42 @@
  */
 
 
-public abstract class ClientWebViewTestCase<V> : TestCase {
+public abstract class Components.WebViewTestCase<V> : TestCase {
 
     protected V? test_view = null;
     protected Application.Configuration? config = null;
 
-    protected ClientWebViewTestCase(string name) {
+    protected WebViewTestCase(string name) {
         base(name);
+    }
+
+    public override void set_up() {
         this.config = new Application.Configuration(Application.Client.SCHEMA_ID);
         this.config.enable_debug = true;
-        ClientWebView.init_web_context(
+
+        WebView.init_web_context(
             this.config,
             File.new_for_path(_BUILD_ROOT_DIR).get_child("src"),
             File.new_for_path("/tmp") // XXX use something better here
         );
         try {
-            ClientWebView.load_resources(GLib.File.new_for_path("/tmp"));
+            WebView.load_resources(GLib.File.new_for_path("/tmp"));
         } catch (GLib.Error err) {
             GLib.assert_not_reached();
         }
+
+        this.test_view = set_up_test_view();
     }
 
-    public override void set_up() {
+    protected override void tear_down() {
-        this.test_view = set_up_test_view();
+        this.config = null;
+        this.test_view = null;
     }
 
     protected abstract V set_up_test_view();
 
     protected virtual void load_body_fixture(string html = "") {
-        ClientWebView client_view = (ClientWebView) this.test_view;
+        WebView client_view = (WebView) this.test_view;
         client_view.load_html(html);
         while (!client_view.is_content_loaded) {
             Gtk.main_iteration();
@@ -42,7 +49,7 @@ public abstract class ClientWebViewTestCase<V> : TestCase {
     }
 
     protected WebKit.JavascriptResult run_javascript(string command) throws Error {
-        ClientWebView view = (ClientWebView) this.test_view;
+        WebView view = (WebView) this.test_view;
         view.run_javascript.begin(command, null, this.async_completion);
         return view.run_javascript.end(async_result());
     }

test/client/components/components-web-view-test.vala

@@ -5,10 +5,10 @@
  * (version 2.1 or later). See the COPYING file in this distribution.
  */
 
-public class ClientWebViewTest : TestCase {
+public class Components.WebViewTest : TestCase {
 
-    public ClientWebViewTest() {
+    public WebViewTest() {
-        base("ClientWebViewTest");
+        base("Components.WebViewTest");
         add_test("init_web_context", init_web_context);
         add_test("load_resources", load_resources);
     }
@@ -18,7 +18,7 @@ public class ClientWebViewTest : TestCase {
             Application.Client.SCHEMA_ID
         );
         config.enable_debug = true;
-        ClientWebView.init_web_context(
+        WebView.init_web_context(
             config,
             File.new_for_path(_BUILD_ROOT_DIR).get_child("src"),
             File.new_for_path("/tmp") // XXX use something better here
@@ -27,7 +27,7 @@ public class ClientWebViewTest : TestCase {
 
     public void load_resources() throws GLib.Error {
         try {
-            ClientWebView.load_resources(GLib.File.new_for_path("/tmp"));
+            WebView.load_resources(GLib.File.new_for_path("/tmp"));
         } catch (GLib.Error err) {
             assert_not_reached();
         }

test/client/composer/composer-web-view-test.vala

@@ -5,7 +5,7 @@
  * (version 2.1 or later). See the COPYING file in this distribution.
  */
 
-public class Composer.WebViewTest : ClientWebViewTestCase<Composer.WebView> {
+public class Composer.WebViewTest : Components.WebViewTestCase<Composer.WebView> {
 
 
     public WebViewTest() {

test/client/util/util-js-test.vala

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 Michael Gratton <mike@vee.net>
+ * Copyright © 2017-2020 Michael Gratton <mike@vee.net>
  *
  * This software is licensed under the GNU Lesser General Public License
  * (version 2.1 or later). See the COPYING file in this distribution.
@@ -7,18 +7,152 @@
 
 public class Util.JS.Test : TestCase {
 
+
+    private JSC.Context? context = null;
+
+
     public Test() {
         base("Util.JS.Test");
-        add_test("escape_string", escape_string);
+        add_test("to_variant", to_variant);
+        add_test("to_value", to_value);
     }
 
-    public void escape_string() throws GLib.Error {
+    public override void set_up() throws GLib.Error {
-        assert(Util.JS.escape_string("\n") == """\n""");
+        this.context = new JSC.Context();
-        assert(Util.JS.escape_string("\r") == """\r""");
+    }
-        assert(Util.JS.escape_string("\t") == """\t""");
-        assert(Util.JS.escape_string("\'") == """\'""");
-        assert(Util.JS.escape_string("\"") == """\"""");
 
-        assert(Util.JS.escape_string("something…\n") == """something…\n""");
+    public override void tear_down() throws GLib.Error {
+        this.context = null;
+    }
+
+    public void to_variant() throws GLib.Error {
+        assert_equal(
+            value_to_variant(new JSC.Value.null(this.context)).print(true),
+            "@mv nothing"
+        );
+        assert_equal(
+            value_to_variant(new JSC.Value.string(this.context, "test")).print(true),
+            "'test'"
+        );
+        assert_equal(
+            value_to_variant(new JSC.Value.number(this.context, 1.0)).print(true),
+            "1.0"
+        );
+        assert_equal(
+            value_to_variant(new JSC.Value.boolean(this.context, true)).print(true),
+            "true"
+        );
+        assert_equal(
+            value_to_variant(new JSC.Value.boolean(this.context, false)).print(true),
+            "false"
+        );
+
+        var value = new JSC.Value.array_from_garray(this.context, null);
+        assert_equal(
+            value_to_variant(value).print(true),
+            "()"
+        );
+
+        var array = new GLib.GenericArray<JSC.Value>();
+        array.add(new JSC.Value.string(this.context, "test"));
+        value = new JSC.Value.array_from_garray(this.context, array);
+        assert_equal(
+            value_to_variant(value).print(true),
+            "['test']"
+        );
+
+        array = new GLib.GenericArray<JSC.Value>();
+        array.add(new JSC.Value.string(this.context, "test1"));
+        array.add(new JSC.Value.string(this.context, "test2"));
+        value = new JSC.Value.array_from_garray(this.context, array);
+        assert_equal(
+            value_to_variant(value).print(true),
+            "['test1', 'test2']"
+        );
+
+        array = new GLib.GenericArray<JSC.Value>();
+        array.add(new JSC.Value.string(this.context, "test"));
+        array.add(new JSC.Value.boolean(this.context, true));
+        value = new JSC.Value.array_from_garray(this.context, array);
+        assert_equal(
+            value_to_variant(value).print(true),
+            "('test', true)"
+        );
+
+        value = new JSC.Value.object(this.context, null, null);
+        assert_equal(
+            value_to_variant(value).print(true),
+            "@a{sv} {}"
+        );
+        value.object_set_property(
+            "test", new JSC.Value.boolean(this.context, true)
+        );
+        assert_equal(
+            value_to_variant(value).print(true),
+            "{'test': <true>}"
+        );
+    }
+
+    public void to_value() throws GLib.Error {
+        var variant = new GLib.Variant.maybe(GLib.VariantType.STRING, null);
+        var value = variant_to_value(this.context, variant);
+        assert_true(value.is_null(), variant.print(true));
+
+        variant = new GLib.Variant.string("test");
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_string(), variant.print(true));
+        assert_equal(value.to_string(), "test", variant.print(true));
+
+        variant = new GLib.Variant.int32(42);
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_number(), variant.print(true));
+        assert_equal<int32?>(value.to_int32(), 42, variant.print(true));
+
+        variant = new GLib.Variant.double(42.0);
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_number(), variant.print(true));
+        assert_within(value.to_double(), 42.0, 0.0000001, variant.print(true));
+
+        variant = new GLib.Variant.boolean(true);
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_boolean(), variant.print(true));
+        assert_true(value.to_boolean(), variant.print(true));
+
+        variant = new GLib.Variant.boolean(false);
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_boolean(), variant.print(true));
+        assert_false(value.to_boolean(), variant.print(true));
+
+        variant = new GLib.Variant.strv({"test"});
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_array(), variant.print(true));
+        assert_true(
+            value.object_get_property_at_index(0).is_string(),
+            variant.print(true)
+        );
+        assert_equal(
+            value.object_get_property_at_index(0).to_string(),
+            "test",
+            variant.print(true)
+        );
+
+        var dict = new GLib.VariantDict();
+        variant = dict.end();
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_object(), variant.print(true));
+
+        dict = new GLib.VariantDict();
+        dict.insert_value("test", new GLib.Variant.boolean(true));
+        variant = dict.end();
+        value = variant_to_value(this.context, variant);
+        assert_true(value.is_object(), variant.print(true));
+        assert_true(
+            value.object_get_property("test").is_boolean(),
+            value.to_string()
+        );
+        assert_true(
+            value.object_get_property("test").to_boolean(),
+            value.to_string()
+        );
     }
 }

test/js/client-page-state-test.vala

@@ -1,63 +0,0 @@
-/*
- * Copyright 2017 Michael Gratton <mike@vee.net>
- *
- * This software is licensed under the GNU Lesser General Public License
- * (version 2.1 or later). See the COPYING file in this distribution.
- */
-
-class ClientPageStateTest : ClientWebViewTestCase<ClientWebView> {
-
-
-    private class TestClientWebView : ClientWebView {
-
-        public TestClientWebView(Application.Configuration config) {
-            base(config);
-        }
-
-    }
-
-
-    public ClientPageStateTest() {
-        base("ClientPageStateTest");
-        add_test("content_loaded", content_loaded);
-
-        try {
-            ClientWebView.load_resources(GLib.File.new_for_path("/tmp"));
-        } catch (GLib.Error err) {
-            GLib.assert_not_reached();
-        }
-
-    }
-
-    public void content_loaded() throws Error {
-        bool content_loaded_triggered = false;
-        this.test_view.content_loaded.connect(() => {
-                content_loaded_triggered = true;
-            });
-
-        assert(!this.test_view.is_content_loaded);
-
-        // XXX sketchy - this call will never return if the thing we
-        // are testing does not work
-        load_body_fixture("OHHAI");
-
-        assert(this.test_view.is_content_loaded);
-        assert(content_loaded_triggered);
-    }
-
-    protected override ClientWebView set_up_test_view() {
-        WebKit.UserScript test_script;
-        test_script = new WebKit.UserScript(
-            "var geary = new PageState()",
-            WebKit.UserContentInjectedFrames.TOP_FRAME,
-            WebKit.UserScriptInjectionTime.START,
-            null,
-            null
-        );
-
-        ClientWebView view = new TestClientWebView(this.config);
-        view.get_user_content_manager().add_script(test_script);
-        return view;
-    }
-
-}

test/js/components-page-state-test.vala

@@ -0,0 +1,168 @@
+/*
+ * Copyright 2017 Michael Gratton <mike@vee.net>
+ *
+ * This software is licensed under the GNU Lesser General Public License
+ * (version 2.1 or later). See the COPYING file in this distribution.
+ */
+
+class Components.PageStateTest : WebViewTestCase<WebView> {
+
+
+    private class TestWebView : Components.WebView {
+
+        public TestWebView(Application.Configuration config) {
+            base(config);
+        }
+
+        public new async void call_void(Util.JS.Callable callable)
+            throws GLib.Error {
+            yield base.call_void(callable, null);
+        }
+
+        public new async string call_returning(Util.JS.Callable callable)
+            throws GLib.Error {
+            return yield base.call_returning<string>(callable, null);
+        }
+
+    }
+
+
+    public PageStateTest() {
+        base("Components.PageStateTest");
+        add_test("content_loaded", content_loaded);
+        add_test("call_void", call_void);
+        add_test("call_void_throws", call_void_throws);
+        add_test("call_returning", call_returning);
+        add_test("call_returning_throws", call_returning_throws);
+
+        try {
+            WebView.load_resources(GLib.File.new_for_path("/tmp"));
+        } catch (GLib.Error err) {
+            GLib.assert_not_reached();
+        }
+
+    }
+
+    public void content_loaded() throws Error {
+        bool content_loaded_triggered = false;
+        this.test_view.content_loaded.connect(() => {
+                content_loaded_triggered = true;
+            });
+
+        assert(!this.test_view.is_content_loaded);
+
+        // XXX sketchy - this call will never return if the thing we
+        // are testing does not work
+        load_body_fixture("OHHAI");
+
+        assert(this.test_view.is_content_loaded);
+        assert(content_loaded_triggered);
+    }
+
+    public void call_void() throws GLib.Error {
+        load_body_fixture("OHHAI");
+        var test_article = this.test_view as TestWebView;
+
+        test_article.call_void.begin(
+            new Util.JS.Callable("testVoid"), this.async_completion
+        );
+        test_article.call_void.end(this.async_result());
+        assert_test_result("void");
+    }
+
+    public void call_void_throws() throws GLib.Error {
+        load_body_fixture("OHHAI");
+        var test_article = this.test_view as TestWebView;
+
+        try {
+            test_article.call_void.begin(
+                new Util.JS.Callable("testThrow").string("void message"),
+                this.async_completion
+            );
+            test_article.call_void.end(this.async_result());
+            assert_not_reached();
+        } catch (Util.JS.Error.EXCEPTION err) {
+            assert_string(
+                err.message
+            ).contains(
+                "testThrow"
+            // WebKitGTK doesn't actually pass any details through:
+            // https://bugs.webkit.org/show_bug.cgi?id=215877
+            // ).contains(
+            //     "Error"
+            // ).contains(
+            //     "void message"
+            // ).contains(
+            //     "components-web-view.js"
+            );
+            assert_test_result("void message");
+        }
+    }
+
+    public void call_returning() throws GLib.Error {
+        load_body_fixture("OHHAI");
+        var test_article = this.test_view as TestWebView;
+
+        test_article.call_returning.begin(
+            new Util.JS.Callable("testReturn").string("check 1-2"),
+            this.async_completion
+        );
+        string ret = test_article.call_returning.end(this.async_result());
+        assert_equal(ret, "check 1-2");
+        assert_test_result("check 1-2");
+    }
+
+    public void call_returning_throws() throws GLib.Error {
+        load_body_fixture("OHHAI");
+        var test_article = this.test_view as TestWebView;
+
+        try {
+            test_article.call_returning.begin(
+                new Util.JS.Callable("testThrow").string("return message"),
+                this.async_completion
+            );
+            test_article.call_returning.end(this.async_result());
+            assert_not_reached();
+        } catch (Util.JS.Error.EXCEPTION err) {
+            assert_string(
+                err.message
+            ).contains(
+                "testThrow"
+            // WebKitGTK doesn't actually pass any details through:
+            // https://bugs.webkit.org/show_bug.cgi?id=215877
+            // ).contains(
+            //     "Error"
+            // ).contains(
+            //     "return message"
+            // ).contains(
+            //     "components-web-view.js"
+            );
+            assert_test_result("return message");
+        }
+    }
+
+    protected override WebView set_up_test_view() {
+        WebKit.UserScript test_script;
+        test_script = new WebKit.UserScript(
+            "var geary = new PageState()",
+            WebKit.UserContentInjectedFrames.TOP_FRAME,
+            WebKit.UserScriptInjectionTime.START,
+            null,
+            null
+        );
+
+        WebView view = new TestWebView(this.config);
+        view.get_user_content_manager().add_script(test_script);
+        return view;
+    }
+
+    private void assert_test_result(string expected)
+        throws GLib.Error {
+        string? result = Util.JS.to_string(
+            run_javascript("geary.testResult")
+            .get_js_value()
+        );
+        assert_equal(result, expected);
+    }
+
+}

test/js/composer-page-state-test.vala

@@ -5,13 +5,13 @@
  * (version 2.1 or later). See the COPYING file in this distribution.
  */
 
-class Composer.PageStateTest : ClientWebViewTestCase<Composer.WebView> {
+class Composer.PageStateTest : Components.WebViewTestCase<Composer.WebView> {
 
     public const string COMPLETE_BODY_TEMPLATE =
         """<div id="geary-body" dir="auto">%s<div><br></div><div><br></div></div><div id="geary-signature" dir="auto"></div>""";
     public const string DIRTY_BODY_TEMPLATE =
         """
-<div id="geary-body" dir="auto" class="geary-focus" contenteditable="true">%s<div><br></div><div><br></div></div>
+<div id="geary-body" dir="auto" contenteditable="true">%s<div><br></div><div><br></div></div>
 <div id="geary-signature" class="geary-no-display" dir="auto" contenteditable="true"></div>
 """;
     public const string CLEAN_BODY_TEMPLATE = """<div id="geary-body" dir="auto">%s<div><br></div><div><br></div></div>""";
@@ -227,7 +227,7 @@ some text
         }
     }
 
-    public void clean_content() throws Error {
+    public void clean_content() throws GLib.Error {
         // XXX split these up into multiple tests
         load_body_fixture("""
 http://example1.com
@@ -257,20 +257,12 @@ unknown://example6.com
 I can send email through smtp.gmail.com:587 or through <a href="https://www.gmail.com/">https://www.gmail.com/</a>
 """;
 
-        try {
+        run_javascript("geary.cleanContent();");
-            run_javascript("geary.cleanContent();");
+        string result = Util.JS.to_string(
-            string result = Util.JS.to_string(
+            run_javascript("window.document.body.innerHTML;")
-                run_javascript("window.document.body.innerHTML;")
+            .get_js_value()
-                .get_js_value()
+        );
-            );
+        assert_equal(result, DIRTY_BODY_TEMPLATE.printf(expected));
-            assert(result == DIRTY_BODY_TEMPLATE.printf(expected));
-        } catch (Util.JS.Error err) {
-            print("Util.JS.Error: %s\n", err.message);
-            assert_not_reached();
-        } catch (Error err) {
-            print("WKError: %s\n", err.message);
-            assert_not_reached();
-        }
     }
 
     public void get_html() throws Error {

test/js/conversation-page-state-test.vala

@@ -5,7 +5,7 @@
  * (version 2.1 or later). See the COPYING file in this distribution.
  */
 
-class ConversationPageStateTest : ClientWebViewTestCase<ConversationWebView> {
+class ConversationPageStateTest : Components.WebViewTestCase<ConversationWebView> {
 
     public ConversationPageStateTest() {
         base("ConversationPageStateTest");

test/meson.build

@@ -82,9 +82,9 @@ test_client_sources = [
   'client/application/application-certificate-manager-test.vala',
   'client/application/application-client-test.vala',
   'client/application/application-configuration-test.vala',
-  'client/components/client-web-view-test.vala',
-  'client/components/client-web-view-test-case.vala',
   'client/components/components-validator-test.vala',
+  'client/components/components-web-view-test-case.vala',
+  'client/components/components-web-view-test.vala',
   'client/composer/composer-web-view-test.vala',
   'client/composer/composer-widget-test.vala',
   'client/util/util-avatar-test.vala',
@@ -92,7 +92,7 @@ test_client_sources = [
   'client/util/util-email-test.vala',
   'client/util/util-js-test.vala',
 
-  'js/client-page-state-test.vala',
+  'js/components-page-state-test.vala',
   'js/composer-page-state-test.vala',
   'js/conversation-page-state-test.vala',
 

test/test-client.vala

@@ -53,10 +53,10 @@ int main(string[] args) {
     client.add_suite(new Application.CertificateManagerTest().suite);
     client.add_suite(new Application.ClientTest().suite);
     client.add_suite(new Application.ConfigurationTest().suite);
-    client.add_suite(new ClientWebViewTest().suite);
+    client.add_suite(new Components.WebViewTest().suite);
+    client.add_suite(new Components.ValidatorTest().suite);
     client.add_suite(new Composer.WebViewTest().suite);
     client.add_suite(new Composer.WidgetTest().suite);
-    client.add_suite(new Components.ValidatorTest().suite);
     client.add_suite(new Util.Avatar.Test().suite);
     client.add_suite(new Util.Cache.Test().suite);
     client.add_suite(new Util.Email.Test().suite);
@@ -64,7 +64,7 @@ int main(string[] args) {
 
     TestSuite js = new TestSuite("js");
 
-    js.add_suite(new ClientPageStateTest().suite);
+    js.add_suite(new Components.PageStateTest().suite);
     js.add_suite(new Composer.PageStateTest().suite);
     js.add_suite(new ConversationPageStateTest().suite);
 

ui/client-web-view-allow-remote-images.js

@@ -1,11 +0,0 @@
-/*
- * Copyright 2016 Michael Gratton <mike@vee.net>
- *
- * This software is licensed under the GNU Lesser General Public License
- * (version 2.1 or later). See the COPYING file in this distribution.
- */
-
-/**
- * Enables remote image loading in a client web view.
- */
-geary.allowRemoteImages = true;

ui/components-web-view.js

@@ -1,12 +1,12 @@
 /*
- * Copyright 2016 Michael Gratton <mike@vee.net>
+ * Copyright © 2016-2020 Michael Gratton <mike@vee.net>
  *
  * This software is licensed under the GNU Lesser General Public License
  * (version 2.1 or later). See the COPYING file in this distribution.
  */
 
 /**
- * Application logic for ClientWebView and subclasses.
+ * Application logic for Components.WebView and subclasses.
  */
 
 let PageState = function() {
@@ -14,13 +14,18 @@ let PageState = function() {
 };
 PageState.prototype = {
     init: function() {
-        this.allowRemoteImages = false;
         this.isLoaded = false;
         this.undoEnabled = false;
         this.redoEnabled = false;
         this.hasSelection = false;
         this.lastPreferredHeight = 0;
 
+        this._selectionChanged = MessageSender("selection_changed");
+        this._contentLoaded = MessageSender("content_loaded");
+        this._preferredHeightChanged = MessageSender("preferred_height_changed");
+        this._commandStackChanged = MessageSender("command_stack_changed");
+        this._documentModified = MessageSender("document_modified");
+
         let state = this;
 
         // Set up an observer to keep track of modifications made to
@@ -40,6 +45,10 @@ PageState.prototype = {
             state.loaded();
         });
 
+        document.addEventListener("selectionchange", function(e) {
+            state.selectionChanged();
+        });
+
         // Coalesce multiple calls to updatePreferredHeight using a
         // timeout to avoid the overhead of multiple JS messages sent
         // to the app and hence view multiple resizes being queued.
@@ -88,6 +97,8 @@ PageState.prototype = {
         window.addEventListener("transitionend", function(e) {
             queuePreferredHeightUpdate();
         }, false); // load does not bubble
+
+        this.testResult = null;
     },
     getPreferredHeight: function() {
         // Return the scroll height of the HTML element since the BODY
@@ -105,10 +116,10 @@ PageState.prototype = {
         // be vaguegly correct when notifying of the HTML load
         // completing.
         this.updatePreferredHeight();
-        window.webkit.messageHandlers.contentLoaded.postMessage(null);
+        this._contentLoaded();
     },
     loadRemoteImages: function() {
-        this.allowRemoteImages = true;
+        window._gearyAllowRemoteResourceLoads = true;
         let images = document.getElementsByTagName("IMG");
         for (let i = 0; i < images.length; i++) {
             let img = images.item(i);
@@ -140,9 +151,6 @@ PageState.prototype = {
     stopBodyObserver: function() {
         this.bodyObserver.disconnect();
     },
-    remoteImageLoadBlocked: function() {
-        window.webkit.messageHandlers.remoteImageLoadBlocked.postMessage(null);
-    },
     /**
      * Sends "preferredHeightChanged" message if it has changed.
      */
@@ -159,9 +167,7 @@ PageState.prototype = {
         // shrink again, leading to visual flicker.
         if (this.isLoaded && height > 0 && height != this.lastPreferredHeight) {
             this.lastPreferredHeight = height;
-            window.webkit.messageHandlers.preferredHeightChanged.postMessage(
+            this._preferredHeightChanged(height);
-                height
-            );
         }
     },
     checkCommandStack: function() {
@@ -171,19 +177,38 @@ PageState.prototype = {
         if (canUndo != this.undoEnabled || canRedo != this.redoEnabled) {
             this.undoEnabled = canUndo;
             this.redoEnabled = canRedo;
-            window.webkit.messageHandlers.commandStackChanged.postMessage(
+            this._commandStackChanged(this.undoEnabled, this.redoEnabled);
-                this.undoEnabled + "," + this.redoEnabled
-            );
         }
     },
     documentModified: function(element) {
-        window.webkit.messageHandlers.documentModified.postMessage(null);
+        this._documentModified();
     },
     selectionChanged: function() {
         let hasSelection = !window.getSelection().isCollapsed;
         if (this.hasSelection != hasSelection) {
             this.hasSelection = hasSelection;
-            window.webkit.messageHandlers.selectionChanged.postMessage(hasSelection);
+            this._selectionChanged(hasSelection);
         }
+    },
+    // Methods below are for unit tests.
+    testVoid: function() {
+        this.testResult = "void";
+    },
+    testReturn: function(value) {
+        this.testResult = value;
+        return value;
+    },
+    testThrow: function(value) {
+        this.testResult = value;
+        throw this.testResult;
     }
 };
+
+let MessageSender = function(name) {
+    return function() {
+        // Since typeof(arguments) == 'object', convert to an array so
+        // that Components.WebView.MessageCallback callbacks get
+        // arrays or tuples rather than dicts as arguments
+        _GearyWebExtension.send(name, Array.from(arguments));
+    };
+};

ui/composer-web-view.css

@@ -43,12 +43,12 @@ body > div#geary-quote {
   padding: 6px !important;
 }
 
-body > div.geary-focus {
+body > div:focus-within {
   background-color: white;
 }
 
-body > div#geary-signature.geary-focus,
+body > div#geary-signature:focus-within,
-body > div#geary-quote.geary-focus {
+body > div#geary-quote:focus-within {
   outline: 1px dashed #ccc !important;
 }
 

ui/composer-web-view.js

@@ -1,6 +1,6 @@
 /*
- * Copyright 2016 Software Freedom Conservancy Inc.
+ * Copyright © 2016 Software Freedom Conservancy Inc.
- * Copyright 2016 Michael Gratton <mike@vee.net>
+ * Copyright © 2016-2020 Michael Gratton <mike@vee.net>
  *
  * This software is licensed under the GNU Lesser General Public License
  * (version 2.1 or later). See the COPYING file in this distribution.
@@ -35,6 +35,9 @@ ComposerPageState.prototype = {
         this.nextSelectionId = 0;
         this.cursorContext = null;
 
+        this._cursorContextChanged = MessageSender("cursor_context_changed");
+        this._dragDropReceived = MessageSender("drag_drop_received");
+
         document.addEventListener("click", function(e) {
             if (e.target.tagName == "A") {
                 e.preventDefault();
@@ -99,7 +102,9 @@ ComposerPageState.prototype = {
         }, true);
 
         // Handle file drag & drop
-        document.body.addEventListener("drop", state.handleFileDrop, true);
+        document.body.addEventListener("drop", function(e) {
+            state.handleFileDrop(e);
+        }, true);
         document.body.addEventListener("allowDrop", function(e) {
             ev.preventDefault();
         }, true);
@@ -118,7 +123,6 @@ ComposerPageState.prototype = {
 
         // Focus within the HTML document
         document.body.focus();
-        this.updateFocusClass(this.bodyPart);
 
         // Set text cursor at appropriate position
         let cursor = document.getElementById("cursormarker");
@@ -346,35 +350,9 @@ ComposerPageState.prototype = {
             let newContext = new EditContext(cursor);
             if (!newContext.equals(this.cursorContext)) {
                 this.cursorContext = newContext;
-                window.webkit.messageHandlers.cursorContextChanged.postMessage(
+                this._cursorContextChanged(newContext.encode());
-                    newContext.encode()
-                );
             }
         }
-
-        while (cursor != null) {
-            let parent = cursor.parentNode;
-            if (parent == document.body) {
-                this.updateFocusClass(cursor);
-                break;
-            }
-            cursor = parent;
-        }
-    },
-    /**
-     * Work around WebKit note yet supporting :focus-inside pseudoclass.
-     */
-    updateFocusClass: function(newFocus) {
-        if (this.focusedPart != null) {
-            this.focusedPart.classList.remove("geary-focus");
-            this.focusedPart = null;
-        }
-        if (newFocus == this.bodyPart ||
-            newFocus == this.signaturePart ||
-            newFocus == this.quotePart) {
-            this.focusedPart = newFocus;
-            this.focusedPart.classList.add("geary-focus");
-        }
     },
     containedInPart: function(target) {
         let inPart = false;
@@ -396,13 +374,14 @@ ComposerPageState.prototype = {
                 continue;
 
             const reader = new FileReader();
+            const state = this;
             reader.onload = (function(filename, imageType) { return function(loadEvent) {
                 // Remove prefixed file type and encoding type
                 var parts = loadEvent.target.result.split(",");
                 if (parts.length < 2)
                     return;
 
-                window.webkit.messageHandlers.dragDropReceived.postMessage({
+                state._dragDropReceived({
                     fileName: encodeURIComponent(filename),
                     fileType: imageType,
                     content: parts[1]

ui/conversation-message.ui

@@ -473,6 +473,7 @@
       <object class="GtkRevealer" id="body_revealer">
         <property name="visible">True</property>
         <property name="can_focus">False</property>
+        <property name="transition_type">slide-up</property>
         <child>
           <object class="GtkGrid">
             <property name="visible">True</property>

ui/conversation-web-view.js

@@ -26,6 +26,8 @@ ConversationPageState.prototype = {
     init: function() {
         PageState.prototype.init.apply(this, []);
 
+        this._deceptiveLinkClicked = MessageSender("deceptive_link_clicked");
+
         let state = this;
         document.addEventListener("click", function(e) {
             if (e.target.tagName == "A" &&
@@ -267,7 +269,7 @@ ConversationPageState.prototype = {
             let reason = ConversationPageState.isDeceptiveText(text, href);
             if (reason != ConversationPageState.NOT_DECEPTIVE) {
                 cancelClick = true;
-                window.webkit.messageHandlers.deceptiveLinkClicked.postMessage({
+                this._deceptiveLinkClicked({
                     reason: reason,
                     text: text,
                     href: href,

ui/org.gnome.Geary.gresource.xml

@@ -9,8 +9,7 @@
     <file compressed="true" preprocess="xml-stripblanks">accounts_editor_servers_pane.ui</file>
     <file compressed="true" preprocess="xml-stripblanks">application-main-window.ui</file>
     <file compressed="true" preprocess="xml-stripblanks">certificate_warning_dialog.glade</file>
-    <file compressed="true">client-web-view.js</file>
+    <file compressed="true">components-web-view.js</file>
-    <file compressed="true">client-web-view-allow-remote-images.js</file>
     <file compressed="true" preprocess="xml-stripblanks">components-attachment-pane.ui</file>
     <file compressed="true" preprocess="xml-stripblanks">components-attachment-pane-menus.ui</file>
     <file compressed="true" preprocess="xml-stripblanks">components-attachment-view.ui</file>