[geary/wip/730682-refine-convo-list] Tune conversation list selection mode a bit.

[Michael Gratton <mjog src gnome org>]

commit b5cd158440d077152754aa15d91679b8f9ab7077
Author: Michael James Gratton <mike vee net>
Date:   Wed Dec 27 00:23:58 2017 +1030

    Tune conversation list selection mode a bit.
    
    * src/client/conversation-list/conversation-list.vala
      (ConversationListBox): Freeze selection when entering selection mode,
      thaw it when leaving, so selecting a conversation in selection mode
      seems a bit less heavyweight. If an evaporating conversation is the
      last marked one, notify that all marked have evaporated.
    
    * src/client/components/main-window.vala (MainWindow): Disable selection
      mode if its marked conversations have evaporated so users don't
      e.g. need to disable it after archiving some conversations. Show a
      conversation if marked as well as if selected.

 src/client/components/main-window.vala             |   76 +++++++++++--------
 .../conversation-list/conversation-list.vala       |   13 +++-
 2 files changed, 56 insertions(+), 33 deletions(-)
---
diff --git a/src/client/components/main-window.vala b/src/client/components/main-window.vala
index e43cb35..55ede0c 100644
--- a/src/client/components/main-window.vala
+++ b/src/client/components/main-window.vala
@@ -82,6 +82,7 @@ public class MainWindow : Gtk.ApplicationWindow {
         this.conversation_list.conversation_selection_changed.connect(on_conversation_selection_changed);
         this.conversation_list.conversation_activated.connect(on_conversation_activated);
         this.conversation_list.item_marked.connect(on_conversation_item_marked);
+        this.conversation_list.marked_conversations_evaporated.connect(on_selection_mode_disabled);
         this.conversation_list.selection_mode_enabled.connect(on_selection_mode_enabled);
         this.conversation_list.visible_conversations_changed.connect(on_visible_conversations_changed);
 
@@ -345,11 +346,47 @@ public class MainWindow : Gtk.ApplicationWindow {
         return (SimpleAction) lookup_action(name);
     }
 
+    private void show_conversation(Geary.App.Conversation? target) {
+        Geary.App.Conversation? current = null;
+        ConversationListBox? listbox = this.conversation_viewer.current_list;
+        if (listbox != null) {
+            current = listbox.conversation;
+        }
+        SimpleAction find_action = get_action(
+            GearyController.ACTION_FIND_IN_CONVERSATION
+        );
+        if (target != null) {
+            if (target != current &&
+                !this.conversation_viewer.is_composer_visible) {
+                this.conversation_viewer.load_conversation.begin(
+                    target,
+                    this.application.config,
+                    this.application.controller.avatar_session,
+                    (obj, ret) => {
+                        try {
+                            this.conversation_viewer.load_conversation.end(ret);
+                            this.application.controller.enable_message_buttons(true);
+                            find_action.set_enabled(true);
+                        } catch (Error err) {
+                            debug("Unable to load conversation: %s",
+                                  err.message);
+                        }
+                    }
+                );
+            }
+        } else {
+            find_action.set_enabled(false);
+            this.application.controller.enable_message_buttons(false);
+            this.conversation_viewer.show_none_selected();
+        }
+    }
+
     private void set_selection_mode_enabled(bool enabled) {
         get_action(ACTION_SELECTION_MODE_DISABLE).set_enabled(enabled);
         get_action(ACTION_SELECTION_MODE_ENABLE).set_enabled(!enabled);
         this.main_toolbar.set_selection_mode_enabled(enabled);
         this.conversation_list.set_selection_mode_enabled(enabled);
+        this.conversation_viewer.show_none_selected();
     }
 
     private void on_conversation_monitor_changed() {
@@ -412,6 +449,7 @@ public class MainWindow : Gtk.ApplicationWindow {
         this.current_folder = folder;
 
         update_headerbar();
+        set_selection_mode_enabled(false);
     }
 
     private void on_account_available(Geary.AccountInformation account) {
@@ -464,38 +502,7 @@ public class MainWindow : Gtk.ApplicationWindow {
     }
 
     private void on_conversation_selection_changed(Geary.App.Conversation? selection) {
-        Geary.App.Conversation? current = null;
-        ConversationListBox? listbox = this.conversation_viewer.current_list;
-        if (listbox != null) {
-            current = listbox.conversation;
-        }
-        SimpleAction find_action = get_action(
-            GearyController.ACTION_FIND_IN_CONVERSATION
-        );
-        if (selection != null) {
-            if (selection != current &&
-                !this.conversation_viewer.is_composer_visible) {
-                this.conversation_viewer.load_conversation.begin(
-                    selection,
-                    this.application.config,
-                    this.application.controller.avatar_session,
-                    (obj, ret) => {
-                        try {
-                            this.conversation_viewer.load_conversation.end(ret);
-                            this.application.controller.enable_message_buttons(true);
-                            find_action.set_enabled(true);
-                        } catch (Error err) {
-                            debug("Unable to load conversation: %s",
-                                  err.message);
-                        }
-                    }
-                );
-            }
-        } else {
-            find_action.set_enabled(false);
-            this.application.controller.enable_message_buttons(false);
-            this.conversation_viewer.show_none_selected();
-        }
+        show_conversation(selection);
     }
 
     private void on_conversation_activated(Geary.App.Conversation activated) {
@@ -513,6 +520,11 @@ public class MainWindow : Gtk.ApplicationWindow {
     }
 
     private void on_conversation_item_marked(ConversationListItem item, bool marked) {
+        if (marked) {
+            show_conversation(item.conversation);
+        } else {
+            this.conversation_viewer.show_none_selected();
+        }
         this.main_toolbar.update_selection_count(
             this.conversation_list.get_marked_items().size
         );
diff --git a/src/client/conversation-list/conversation-list.vala 
b/src/client/conversation-list/conversation-list.vala
index dd4b4b2..8c2f410 100644
--- a/src/client/conversation-list/conversation-list.vala
+++ b/src/client/conversation-list/conversation-list.vala
@@ -69,6 +69,11 @@ public class ConversationList : Gtk.ListBox {
     public signal void selection_mode_enabled();
 
     /**
+     * Fired when all marked conversations were removed from the folder.
+     */
+    public signal void marked_conversations_evaporated();
+
+    /**
      * Fired when a list item was marked as selected in selection mode.
      */
     public signal void item_marked(ConversationListItem item, bool marked);
@@ -238,7 +243,9 @@ public class ConversationList : Gtk.ListBox {
     }
 
     internal void set_selection_mode_enabled(bool enabled) {
-        if (!enabled) {
+        if (enabled) {
+            freeze_selection();
+        } else {
             // Call to_array here to get a copy of the value
             // collection, since unmarking the items will cause the
             // underlying map to be modified
@@ -246,6 +253,7 @@ public class ConversationList : Gtk.ListBox {
                 item.set_marked(false);
             }
             this.marked.clear();
+            thaw_selection();
         }
         this.is_selection_mode_enabled = enabled;
     }
@@ -406,6 +414,9 @@ public class ConversationList : Gtk.ListBox {
             foreach (Geary.App.Conversation convo in removed) {
                 this.marked.remove(convo);
             }
+            if (this.marked.is_empty) {
+                marked_conversations_evaporated();
+            }
         }
     }