[geary/wip/721828-undo] Refinements of last commit

[Jim Nelson <jnelson src gnome org>]

commit 1dd51d59bf6f6637003aa8638a716c7e4fd9a7a8
Author: Jim Nelson <jim yorba org>
Date:   Tue Dec 23 15:34:08 2014 -0800

    Refinements of last commit

 .../imap-engine/imap-engine-minimal-folder.vala    |   18 +-------
 .../imap-engine/imap-engine-revokable-move.vala    |   48 +++++++++++++++-----
 2 files changed, 38 insertions(+), 28 deletions(-)
---
diff --git a/src/engine/imap-engine/imap-engine-minimal-folder.vala 
b/src/engine/imap-engine/imap-engine-minimal-folder.vala
index 2fa79b1..32e2936 100644
--- a/src/engine/imap-engine/imap-engine-minimal-folder.vala
+++ b/src/engine/imap-engine/imap-engine-minimal-folder.vala
@@ -46,9 +46,6 @@ private class Geary.ImapEngine.MinimalFolder : Geary.AbstractFolder, Geary.Folde
     private uint open_remote_timer_id = 0;
     private int reestablish_delay_msec = DEFAULT_REESTABLISH_DELAY_MSEC;
     
-    // Used by ImapEngine Revokables.
-    public signal void uids_removed(Gee.Collection<Imap.UID> uids);
-    
     public MinimalFolder(GenericAccount account, Imap.Account remote, ImapDB.Account local,
         ImapDB.Folder local_folder, SpecialFolderType special_folder_type) {
         _account = account;
@@ -78,19 +75,6 @@ private class Geary.ImapEngine.MinimalFolder : Geary.AbstractFolder, Geary.Folde
     public override void notify_email_removed(Gee.Collection<Geary.EmailIdentifier> ids) {
         // fire base signal first
         base.notify_email_removed(ids);
-        
-        // parse out UIDs and fire signal for Revokables
-        Gee.HashSet<Imap.UID> uids = new Gee.HashSet<Imap.UID>();
-        foreach (Geary.EmailIdentifier id in ids) {
-            ImapDB.EmailIdentifier? imapdb_id = id as ImapDB.EmailIdentifier;
-            if (imapdb_id != null && imapdb_id.uid != null)
-                uids.add(imapdb_id.uid);
-        }
-        
-        debug("Notifying of %d UIDs removed from %s", uids.size, to_string());
-        
-        if (uids.size > 0)
-            uids_removed(uids);
     }
     
     public void set_special_folder_type(SpecialFolderType new_type) {
@@ -1287,7 +1271,7 @@ private class Geary.ImapEngine.MinimalFolder : Geary.AbstractFolder, Geary.Folde
         replay_queue.schedule(move);
         yield move.wait_for_ready_async(cancellable);
         
-        return new RevokableMove(account, path, destination, move.destination_uids);
+        return new RevokableMove(_account, path, destination, move.destination_uids);
     }
     
     private void on_email_flags_changed(Gee.Map<Geary.EmailIdentifier, Geary.EmailFlags> changed) {
diff --git a/src/engine/imap-engine/imap-engine-revokable-move.vala 
b/src/engine/imap-engine/imap-engine-revokable-move.vala
index 80c047e..646e4bf 100644
--- a/src/engine/imap-engine/imap-engine-revokable-move.vala
+++ b/src/engine/imap-engine/imap-engine-revokable-move.vala
@@ -5,18 +5,25 @@
  */
 
 private class Geary.ImapEngine.RevokableMove : Revokable {
-    private Account account;
+    private GenericAccount account;
     private FolderPath original_source;
     private FolderPath original_dest;
     private Gee.Set<Imap.UID> uids;
-    private MinimalFolder? dest_folder = null;
     
-    public RevokableMove(Account account, FolderPath original_source, FolderPath original_dest,
+    public RevokableMove(GenericAccount account, FolderPath original_source, FolderPath original_dest,
         Gee.Set<Imap.UID> uids) {
         this.account = account;
         this.original_source = original_source;
         this.original_dest = original_dest;
         this.uids = uids;
+        
+        account.folders_available_unavailable.connect(on_folders_available_unavailable);
+        account.email_removed.connect(on_folder_email_removed);
+    }
+    
+    ~RevokableMove() {
+        account.folders_available_unavailable.disconnect(on_folders_available_unavailable);
+        account.email_removed.disconnect(on_folder_email_removed);
     }
     
     public override async bool revoke_async(Cancellable? cancellable) throws Error {
@@ -33,6 +40,7 @@ private class Geary.ImapEngine.RevokableMove : Revokable {
     
     private async bool internal_revoke_async(Cancellable? cancellable) throws Error {
         // moving from original destination to original source
+        MinimalFolder? dest_folder = null;
         try {
             Geary.Folder folder = yield account.fetch_folder_async(original_dest, cancellable);
             dest_folder = folder as ImapEngine.MinimalFolder;
@@ -43,14 +51,12 @@ private class Geary.ImapEngine.RevokableMove : Revokable {
         if (dest_folder == null)
             return can_revoke = false;
         
-        // trap removal of the UIDs we're moving
-        dest_folder.uids_removed.connect(on_folder_uids_removed);
-        
         // open, revoke, close, ensuring the close and signal disconnect are performed in all cases
         try {
             yield dest_folder.open_async(Geary.Folder.OpenFlags.NO_DELAY, cancellable);
             
-            if (!yield dest_folder.revoke_move_async(uids, original_source, cancellable))
+            // watch out for messages detected as gone when folder is opened
+            if (can_revoke && !yield dest_folder.revoke_move_async(uids, original_source, cancellable))
                 can_revoke = false;
         } finally {
             // note that the Cancellable is not used
@@ -59,19 +65,39 @@ private class Geary.ImapEngine.RevokableMove : Revokable {
             } catch (Error err) {
                 // ignored
             }
-            
-            dest_folder.uids_removed.disconnect(on_folder_uids_removed);
-            dest_folder = null;
         }
         
         return can_revoke;
     }
     
-    private void on_folder_uids_removed(Gee.Collection<Imap.UID> removed_uids) {
+    private void on_folders_available_unavailable(Gee.List<Folder>? available, Gee.List<Folder>? 
unavailable) {
+        // look for either of the original folders going away
+        if (unavailable != null) {
+            foreach (Folder folder in unavailable) {
+                if (folder.path.equal_to(original_source) || folder.path.equal_to(original_dest)) {
+                    can_revoke = false;
+                    
+                    break;
+                }
+            }
+        }
+    }
+    
+    private void on_folder_email_removed(Folder folder, Gee.Collection<EmailIdentifier> ids) {
+        // watch for destination folder's UIDs being removed
+        if (!folder.path.equal_to(original_dest))
+            return;
+        
         // one-way switch
         if (!can_revoke)
             return;
         
+        // convert generic identifiers to UIDs
+        Gee.HashSet<Imap.UID> removed_uids = traverse<EmailIdentifier>(ids)
+            .cast_object<ImapDB.EmailIdentifier>()
+            .map<Imap.UID>(id => id.uid)
+            .to_hash_set();
+        
         // otherwise, ability to revoke is best-effort
         uids.remove_all(removed_uids);
         can_revoke = uids.size > 0;