[geary/wip/conversation-polish: 25/26] Display a placeholder when email body loading is taking a long time

[Michael Gratton <mjog src gnome org>]

commit c64eb72e69854b66fa06b24dbf04897c55d96f76
Author: Michael Gratton <mike vee net>
Date:   Sat Feb 2 13:03:10 2019 +1100

    Display a placeholder when email body loading is taking a long time

 .../conversation-viewer/conversation-email.vala    |  6 ++++-
 .../conversation-viewer/conversation-message.vala  | 26 ++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)
---
diff --git a/src/client/conversation-viewer/conversation-email.vala 
b/src/client/conversation-viewer/conversation-email.vala
index 875f43ec..44f6724b 100644
--- a/src/client/conversation-viewer/conversation-email.vala
+++ b/src/client/conversation-viewer/conversation-email.vala
@@ -551,7 +551,7 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
         );
 
         this.body_loading_timeout = new Geary.TimeoutManager.milliseconds(
-            BODY_LOAD_TIMEOUT_MSEC, this.primary_message.start_progress_pulse
+            BODY_LOAD_TIMEOUT_MSEC, this.on_body_loading_timeout
         );
 
         pack_start(this.primary_message, true, true, 0);
@@ -1006,6 +1006,10 @@ public class ConversationEmail : Gtk.Box, Geary.BaseInterface {
         op.run_dialog(window);
     }
 
+    private void on_body_loading_timeout() {
+        this.primary_message.show_loading_pane();
+    }
+
     private void on_flag_remote_images(ConversationMessage view) {
         // XXX check we aren't already auto loading the image
         mark_email(Geary.EmailFlags.LOAD_REMOTE_IMAGES, null);
diff --git a/src/client/conversation-viewer/conversation-message.vala 
b/src/client/conversation-viewer/conversation-message.vala
index 4ab3bbf1..c1712851 100644
--- a/src/client/conversation-viewer/conversation-message.vala
+++ b/src/client/conversation-viewer/conversation-message.vala
@@ -504,6 +504,32 @@ public class ConversationMessage : Gtk.Grid, Geary.BaseInterface {
         body_revealer.set_reveal_child(false);
     }
 
+    /** Shows a panel when an email is being loaded. */
+    public void show_loading_pane() {
+        Components.PlaceholderPane pane = new Components.PlaceholderPane();
+        pane.icon_name = "content-loading-symbolic";
+        pane.title = "";
+        pane.subtitle = "";
+
+        // Don't want to break the announced freeze for 0.13, so just
+        // hope the icon gets the message across for now and replace
+        // them with the ones below for 0.14.
+
+        // Translators: Title label for placeholder when multiple
+        // an error occurs loading a message for display.
+        //pane.title = _("A problem occurred");
+        // Translators: Sub-title label for placeholder when multiple
+        // an error occurs loading a message for display.
+        //pane.subtitle = _(
+        //    "This email cannot currently be displayed"
+        //);
+        this.body_placeholder = pane;
+        this.web_view.hide();
+        this.body_container.add(pane);
+        show_message_body(true);
+        start_progress_pulse();
+    }
+
     /** Shows an error panel when email loading failed. */
     public void show_load_error_pane() {
         Components.PlaceholderPane pane = new Components.PlaceholderPane();