Display To:, From:, and Subject: in message viewer: #3812

Fields added.  However, it would be nice to use formatting to separate them from the body of the message.  This is not easy with Gtk.TextView/Gtk.TextBuffer; see https://bugzilla.gnome.org/show_bug.cgi?id=59390.  This may push us to move to Webkit earlier rather than later.

src/client/ui/main-window.vala

@@ -237,13 +237,10 @@ public class MainWindow : Gtk.Window {
     }
     
     private void on_message_selected(Geary.Email? email) {
-        if (email == null) {
-            message_buffer.set_text("");
-            
-            return;
-        }
+        message_buffer.clear();
         
-        do_select_message.begin(email, on_select_message_completed);
+        if (email != null)
+            do_select_message.begin(email, on_select_message_completed);
     }
     
     private async void do_select_message(Geary.Email email) throws Error {
@@ -253,13 +250,10 @@ public class MainWindow : Gtk.Window {
             return;
         }
         
-        Geary.Email full = yield current_folder.fetch_email_async(email.location.position,
-            Geary.Email.Field.HEADER | Geary.Email.Field.BODY);
+        Geary.Email for_buffer = yield current_folder.fetch_email_async(email.location.position,
+            MessageBuffer.REQUIRED_FIELDS);
         
-        Geary.Memory.AbstractBuffer buffer = full.get_message().get_first_mime_part_of_content_type(
-            "text/plain");
-        
-        message_buffer.set_text(buffer.to_utf8());
+        message_buffer.display_email(for_buffer);
     }
     
     private void on_select_message_completed(Object? source, AsyncResult result) {

src/client/ui/message-buffer.vala

@@ -5,7 +5,54 @@
  */
 
 public class MessageBuffer : Gtk.TextBuffer {
+    public const Geary.Email.Field REQUIRED_FIELDS =
+        Geary.Email.Field.HEADER
+        | Geary.Email.Field.BODY
+        | Geary.Email.Field.ORIGINATORS
+        | Geary.Email.Field.RECEIVERS
+        | Geary.Email.Field.SUBJECT;
+    
     public MessageBuffer() {
     }
+    
+    public void clear() {
+        set_text("");
+    }
+    
+    // Would very much like to use Pango markup to format the text, however, it's not supported
+    // in Gtk.TextBuffer/Gtk.TextView by default, meaning the implementor has to devise their own
+    // markup language, parse the buffer, and so on. See:
+    // https://bugzilla.gnome.org/show_bug.cgi?id=59390
+    public void display_email(Geary.Email email) throws Error {
+        StringBuilder builder = new StringBuilder();
+        
+        // From:
+        if (email.from != null && email.from.size > 0)
+            builder.append_printf(_("From: %s\n"), email.from.to_string());
+        else if (email.sender != null && email.sender.size > 0)
+            builder.append_printf(_("Sender: %s\n"), email.sender.to_string());
+        
+        // To:
+        if (email.to != null && email.to.size > 0)
+            builder.append_printf(_("To: %s\n"), email.to.to_string());
+        
+        if (email.cc != null && email.cc.size > 0)
+            builder.append_printf(_("Cc: %s\n"), email.cc.to_string());
+        
+        if (email.bcc != null && email.bcc.size > 0)
+            builder.append_printf(_("Bcc: %s"), email.bcc.to_string());
+        
+        // Subject:
+        if (email.subject != null)
+            builder.append_printf(_("Subject: %s\n"), email.subject.value);
+        
+        // Message body
+        Geary.Memory.AbstractBuffer buffer = email.get_message().get_first_mime_part_of_content_type(
+            "text/plain");
+        builder.append("\n");
+        builder.append(buffer.to_utf8());
+        
+        set_text(builder.str);
+    }
 }
 

src/engine/api/geary-email.vala

@@ -153,6 +153,10 @@ public class Geary.Email : Object {
         fields |= Field.PROPERTIES;
     }
     
+    /**
+     * This method requires Geary.Email.Field.HEADER and Geary.Email.Field.BODY be present.
+     * If not, EngineError.INCOMPLETE_MESSAGE is thrown.
+     */
     public Geary.RFC822.Message get_message() throws EngineError, RFC822.Error {
         if (message != null)
             return message;

src/engine/sqlite/api/sqlite-folder.vala

@@ -178,7 +178,7 @@ public class Geary.Sqlite.Folder : Geary.AbstractFolder, Geary.LocalFolder {
                 to_string());
         }
         
-        if (!message_row.fields.is_set(required_fields)) {
+        if (!message_row.fields.fulfills(required_fields)) {
             throw new EngineError.INCOMPLETE_MESSAGE(
                 "Message at position %d in folder %s only fulfills %Xh fields", position, to_string(),
                 message_row.fields);