[geary/wip/cleanup-imap-folders-725695] Clean up Imap.Account's folder map

[Charles Lindsay <clindsay src gnome org>]

commit 4b3a5cea8518778c803373cf62a3b00dfad8414c
Author: Charles Lindsay <chaz yorba org>
Date:   Tue Mar 4 15:24:32 2014 -0800

    Clean up Imap.Account's folder map

 .../imap-engine/imap-engine-generic-account.vala   |    3 +++
 src/engine/imap/api/imap-account.vala              |    9 +++++++++
 2 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/src/engine/imap-engine/imap-engine-generic-account.vala 
b/src/engine/imap-engine/imap-engine-generic-account.vala
index 29f7478..ad7d475 100644
--- a/src/engine/imap-engine/imap-engine-generic-account.vala
+++ b/src/engine/imap-engine/imap-engine-generic-account.vala
@@ -726,6 +726,9 @@ private abstract class Geary.ImapEngine.GenericAccount : Geary.AbstractAccount {
         if (engine_added.size > 0 || engine_removed.size > 0)
             notify_folders_added_removed(sort_by_path(engine_added), sort_by_path(engine_removed));
         
+        remote.folders_removed(Geary.traverse<Geary.Folder>(engine_removed)
+            .map<FolderPath>(f => f.path).to_array_list());
+        
         // report all altered folders
         if (altered_paths.size > 0) {
             Gee.ArrayList<Geary.Folder> altered = new Gee.ArrayList<Geary.Folder>();
diff --git a/src/engine/imap/api/imap-account.vala b/src/engine/imap/api/imap-account.vala
index c04d314..0f4de58 100644
--- a/src/engine/imap/api/imap-account.vala
+++ b/src/engine/imap/api/imap-account.vala
@@ -199,6 +199,15 @@ private class Geary.Imap.Account : BaseObject {
         return folder;
     }
     
+    internal void folders_removed(Gee.Collection<FolderPath> paths) {
+        foreach (FolderPath path in paths) {
+            if (path_to_mailbox.has_key(path))
+                path_to_mailbox.unset(path);
+            if (folders.has_key(path))
+                folders.unset(path);
+        }
+    }
+    
     public async int fetch_unseen_count_async(FolderPath path, Cancellable? cancellable)
         throws Error {
         check_open();