[geary/mjog/account-command-stacks: 64/77] Move policy decision for folders supporting trash to controller

[Michael Gratton <mjog src gnome org>]

commit b20625b2d6acf1a16339a9a4edfe5df73ef520bb
Author: Michael Gratton <mike vee net>
Date:   Wed Oct 30 14:26:05 2019 +1100

    Move policy decision for folders supporting trash to controller
    
    This allows classes other than the main window to make the determination
    for other folders.

 src/client/application/application-controller.vala | 11 +++++++++++
 src/client/components/main-window.vala             | 23 +++++++++++-----------
 2 files changed, 22 insertions(+), 12 deletions(-)
---
diff --git a/src/client/application/application-controller.vala 
b/src/client/application/application-controller.vala
index bcfda6a8..3b24f65d 100644
--- a/src/client/application/application-controller.vala
+++ b/src/client/application/application-controller.vala
@@ -21,6 +21,17 @@ public class Application.Controller : Geary.BaseObject {
     private const uint MAX_AUTH_ATTEMPTS = 3;
 
 
+    /** Determines if conversations can be trashed from the given folder. */
+    public static bool does_folder_support_trash(Geary.Folder? target) {
+        return (
+            target != null &&
+            target.special_folder_type != TRASH &&
+            !target.properties.is_local_only &&
+            (target as Geary.FolderSupport.Move) != null
+        );
+    }
+
+
     /**
      * Collects objects and state related to a single open account.
      */
diff --git a/src/client/components/main-window.vala b/src/client/components/main-window.vala
index 4ca33df0..bdf43fbf 100644
--- a/src/client/components/main-window.vala
+++ b/src/client/components/main-window.vala
@@ -174,6 +174,15 @@ public class MainWindow : Gtk.ApplicationWindow, Geary.BaseInterface {
     /** The attachment manager for this window. */
     public Application.AttachmentManager attachments { get; private set; }
 
+    /** Determines if conversations in the selected folder can be trashed. */
+    public bool selected_folder_supports_trash {
+        get {
+            return Application.Controller.does_folder_support_trash(
+                this.selected_folder
+            );
+        }
+    }
+
     /** Determines if a composer is currently open in this window. */
     public bool has_composer {
         get {
@@ -692,7 +701,7 @@ public class MainWindow : Gtk.ApplicationWindow, Geary.BaseInterface {
             update_conversation_actions(NONE);
             this.conversation_viewer.show_loading();
             this.main_toolbar.update_trash_button(
-                !this.is_shift_down && selected_folder_supports_trash()
+                !this.is_shift_down && this.selected_folder_supports_trash
             );
 
             if (folder != null) {
@@ -1178,7 +1187,7 @@ public class MainWindow : Gtk.ApplicationWindow, Geary.BaseInterface {
             sensitive && (selected_folder is Geary.FolderSupport.Archive)
         );
         get_action(ACTION_TRASH_CONVERSATION).set_enabled(
-            sensitive && selected_folder_supports_trash()
+            sensitive && this.selected_folder_supports_trash
         );
         get_action(ACTION_DELETE_CONVERSATION).set_enabled(
             sensitive && (selected_folder is Geary.FolderSupport.Remove)
@@ -1260,16 +1269,6 @@ public class MainWindow : Gtk.ApplicationWindow, Geary.BaseInterface {
         return (SimpleAction) lookup_action(name);
     }
 
-    private bool selected_folder_supports_trash() {
-        Geary.Folder? current = this.selected_folder;
-        return (
-            current != null &&
-            current.special_folder_type != TRASH &&
-            !selected_folder.properties.is_local_only &&
-            (selected_folder as Geary.FolderSupport.Move) != null
-        );
-    }
-
     private void on_scan_completed(Geary.App.ConversationMonitor monitor) {
         // Done scanning.  Check if we have enough messages to fill
         // the conversation list; if not, trigger a load_more();