From 5b0d493ff07d83ea2fc893e5f166921d56aa8eeb Mon Sep 17 00:00:00 2001
From: Jim Nelson <jim@yorba.org>
Date: Sat, 6 Jul 2013 20:21:14 -0700
Subject: [PATCH] Prevent flag watcher from looping forever

Bruno Girin on the mailing list noticed Geary churning constantly.
Some investigation and I was able to repro it -- an off-by-one
error was causing the flag watcher to forever pull the oldest
email's flags.  This catches that as well as spaces out the
timeout so the next round of fetching happens a full timeout
sequence after the last flags are pulled (rather than starting at
regular intervals, which can come in close on low-powered machines).
---
 .../imap-engine-email-flag-watcher.vala       | 40 ++++++++++++-------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/src/engine/imap-engine/imap-engine-email-flag-watcher.vala b/src/engine/imap-engine/imap-engine-email-flag-watcher.vala
index d86a65f7..37519998 100644
--- a/src/engine/imap-engine/imap-engine-email-flag-watcher.vala
+++ b/src/engine/imap-engine/imap-engine-email-flag-watcher.vala
@@ -67,23 +67,32 @@ private class Geary.ImapEngine.EmailFlagWatcher : BaseObject {
     }
     
     private bool on_flag_watch() {
-        if (enabled)
-            flag_watch_async.begin();
+        if (!enabled) {
+            // try again later
+            return true;
+        }
         
-        return true;
+        flag_watch_async.begin();
+        
+        watch_id = 0;
+        
+        // return false and reschedule when finished
+        return false;
     }
     
     private async void flag_watch_async() {
-        if (in_flag_watch)
-            return;
-        
-        in_flag_watch = true;
-        try {
-            yield do_flag_watch_async();
-        } catch (Error err) {
-            message("Flag watch error: %s", err.message);
+        if (!in_flag_watch) {
+            in_flag_watch = true;
+            try {
+                yield do_flag_watch_async();
+            } catch (Error err) {
+                message("Flag watch error: %s", err.message);
+            }
+            in_flag_watch = false;
         }
-        in_flag_watch = false;
+        
+        if (watch_id == 0)
+            watch_id = Timeout.add_seconds(seconds, on_flag_watch);
     }
     
     private async void do_flag_watch_async() throws Error {
@@ -96,11 +105,12 @@ private class Geary.ImapEngine.EmailFlagWatcher : BaseObject {
             Gee.List<Geary.Email>? list_local;
             if (lowest == null) {
                 list_local = yield folder.list_email_async(-1, PULL_CHUNK_COUNT,
-                    Email.Field.FLAGS, Geary.Folder.ListFlags.LOCAL_ONLY, cancellable);
+                    Geary.Email.Field.FLAGS, Geary.Folder.ListFlags.LOCAL_ONLY, cancellable);
             } else {
                 // note using negative count to move down the stack
                 list_local = yield folder.list_email_by_id_async(lowest, 0 - PULL_CHUNK_COUNT,
-                    Email.Field.FLAGS, Geary.Folder.ListFlags.LOCAL_ONLY, cancellable);
+                    Geary.Email.Field.FLAGS, Geary.Folder.ListFlags.LOCAL_ONLY | Geary.Folder.ListFlags.EXCLUDING_ID,
+                    cancellable);
             }
             
             if (list_local == null || list_local.size == 0)
@@ -120,6 +130,8 @@ private class Geary.ImapEngine.EmailFlagWatcher : BaseObject {
             
             // Fetch e-mail from folder using force update, which will cause the cache to be bypassed
             // and the latest to be gotten from the server (updating the cache in the process)
+            Logging.debug(Logging.Flag.PERIODIC, "do_flag_watch_async: fetching %d flags for %s",
+                local_map.keys.size, folder.to_string());
             Gee.List<Geary.Email>? list_remote = yield folder.list_email_by_sparse_id_async(local_map.keys,
                 Email.Field.FLAGS, Geary.Folder.ListFlags.FORCE_UPDATE, cancellable);
             if (list_remote == null || list_remote.size == 0)