Replace FolderList.Tree mail hooks with plugin

Using a plugin to manage folder new mail highlighting so it works in the
same way as for other notifications.

po/POTFILES.in

@@ -97,6 +97,8 @@ src/client/plugin/plugin-plugin-base.vala
 src/client/plugin/plugin-trusted-etension.vala
 src/client/plugin/desktop-notifications/desktop-notifications.plugin.in
 src/client/plugin/desktop-notifications/desktop-notifications.vala
+src/client/plugin/folder-highlight/folder-highlight.plugin.in
+src/client/plugin/folder-highlight/folder-highlight.vala
 src/client/plugin/messaging-menu/messaging-menu.plugin.in
 src/client/plugin/messaging-menu/messaging-menu.vala
 src/client/plugin/notification-badge/notification-badge.plugin.in

src/client/application/application-plugin-manager.vala

@@ -15,6 +15,7 @@ public class Application.PluginManager : GLib.Object {
     // application stats up
     private const string[] AUTOLOAD_MODULES = {
         "desktop-notifications",
+        "folder-highlight",
         "notification-badge",
     };
 

src/client/folder-list/folder-list-tree.vala

@@ -14,11 +14,6 @@ public class FolderList.Tree : Sidebar.Tree, Geary.BaseInterface {
     private const int INBOX_ORDINAL = -2; // First account branch is zero
     private const int SEARCH_ORDINAL = -1;
 
-    private const Geary.SpecialFolderType[] INTERESTING_FOLDERS = {
-        INBOX,
-        NONE
-    };
-
 
     public signal void folder_selected(Geary.Folder? folder);
     public signal void copy_conversation(Geary.Folder folder);
@@ -113,7 +108,6 @@ public class FolderList.Tree : Sidebar.Tree, Geary.BaseInterface {
         if (folder.special_folder_type == Geary.SpecialFolderType.INBOX)
             inboxes_branch.add_inbox(folder);
 
-        folder.email_locally_appended.connect(on_email_appended);
         account_branch.add_folder(folder);
     }
 
@@ -141,7 +135,6 @@ public class FolderList.Tree : Sidebar.Tree, Geary.BaseInterface {
         if (folder.special_folder_type == Geary.SpecialFolderType.INBOX)
             inboxes_branch.remove_inbox(folder.account);
 
-        folder.email_locally_appended.disconnect(on_email_appended);
         account_branch.remove_folder(folder);
     }
 
@@ -269,11 +262,4 @@ public class FolderList.Tree : Sidebar.Tree, Geary.BaseInterface {
             graft(branch, branch.account.information.ordinal);
     }
 
-    private void on_email_appended(Geary.Folder folder,
-                                   Gee.Collection<Geary.EmailIdentifier> ids) {
-        if (folder.special_folder_type in INTERESTING_FOLDERS) {
-            set_has_new(folder, true);
-        }
-    }
-
 }

src/client/plugin/folder-highlight/folder-highlight.plugin.in

@@ -0,0 +1,4 @@
+[Plugin]
+Module=folder-highlight
+Name=Folder Highlight
+Description=Highlights folders that have newly delivered mail

src/client/plugin/folder-highlight/folder-highlight.vala

@@ -0,0 +1,95 @@
+/*
+ * Copyright © 2016 Software Freedom Conservancy Inc.
+ * Copyright © 2019-2020 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.
+ */
+
+[ModuleInit]
+public void peas_register_types(TypeModule module) {
+    Peas.ObjectModule obj = module as Peas.ObjectModule;
+    obj.register_extension_type(
+        typeof(Plugin.PluginBase),
+        typeof(Plugin.FolderHighlight)
+    );
+}
+
+/**
+ * Manages highlighting folders that have newly delivered mail
+ */
+public class Plugin.FolderHighlight :
+    PluginBase, NotificationExtension, TrustedExtension {
+
+
+    private const Geary.SpecialFolderType[] MONITORED_TYPES = {
+        INBOX, NONE
+    };
+
+
+    public NotificationContext notifications {
+        get; construct set;
+    }
+
+    public global::Application.Client client_application {
+        get; construct set;
+    }
+
+    public global::Application.PluginManager client_plugins {
+        get; construct set;
+    }
+
+    public override async void activate() throws GLib.Error {
+        this.notifications.new_messages_arrived.connect(on_new_messages_arrived);
+        this.notifications.new_messages_retired.connect(on_new_messages_retired);
+
+        FolderStore folders = yield this.notifications.get_folders();
+        folders.folders_available.connect(
+            (folders) => check_folders(folders)
+        );
+        folders.folders_unavailable.connect(
+            (folders) => check_folders(folders)
+        );
+        folders.folders_type_changed.connect(
+            (folders) => check_folders(folders)
+        );
+        check_folders(folders.get_folders());
+    }
+
+    public override async void deactivate(bool is_shutdown) throws GLib.Error {
+        // no-op
+    }
+
+    private void check_folders(Gee.Collection<Folder> folders) {
+        foreach (Folder folder in folders) {
+            if (folder.folder_type in MONITORED_TYPES) {
+                this.notifications.start_monitoring_folder(folder);
+            } else {
+                this.notifications.stop_monitoring_folder(folder);
+            }
+        }
+    }
+
+    private void on_new_messages_arrived(Folder folder,
+                                         int total,
+                                         Gee.Collection<EmailIdentifier> added) {
+        Geary.Folder? engine = this.client_plugins.get_engine_folder(folder);
+        if (engine != null) {
+            foreach (global::Application.MainWindow window
+                     in this.client_application.get_main_windows()) {
+                window.folder_list.set_has_new(engine, true);
+            }
+        }
+    }
+
+    private void on_new_messages_retired(Folder folder, int total) {
+        Geary.Folder? engine = this.client_plugins.get_engine_folder(folder);
+        if (engine != null) {
+            foreach (global::Application.MainWindow window
+                     in this.client_application.get_main_windows()) {
+                window.folder_list.set_has_new(engine, false);
+            }
+        }
+    }
+
+}

src/client/plugin/folder-highlight/meson.build

@@ -0,0 +1,26 @@
+
+plugin_name = 'folder-highlight'
+
+plugin_src = join_paths(plugin_name + '.vala')
+plugin_data = join_paths(plugin_name + '.plugin')
+plugin_dest = join_paths(plugins_dir, plugin_name)
+
+shared_module(
+  plugin_name,
+  sources: plugin_src,
+  dependencies: plugin_dependencies,
+  include_directories: config_h_dir,
+  vala_args: geary_vala_args,
+  c_args: plugin_c_args,
+  install: true,
+  install_dir: plugin_dest
+)
+
+i18n.merge_file(
+  input: plugin_data + '.in',
+  output: plugin_data,
+  type: 'desktop',
+  po_dir: po_dir,
+  install: true,
+  install_dir: plugin_dest
+)

src/client/plugin/meson.build

@@ -23,5 +23,6 @@ plugin_dependencies = [
 plugin_c_args = geary_c_args
 
 subdir('desktop-notifications')
+subdir('folder-highlight')
 subdir('messaging-menu')
 subdir('notification-badge')