From c3796c61cd69f240ea0f0f97f2ba95ea9ab2c8e9 Mon Sep 17 00:00:00 2001
From: David Baker <dave@matrix.org>
Date: Wed, 10 Feb 2016 10:40:42 +0000
Subject: [PATCH] Use a promise for when the connection comes back

---
 lib/sync.js | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/lib/sync.js b/lib/sync.js
index b241c339d..4c36ecf54 100644
--- a/lib/sync.js
+++ b/lib/sync.js
@@ -70,6 +70,7 @@ function SyncApi(client, opts) {
     this._syncState = null;
     this._running = false;
     this._keepAliveTimer = null;
+    this._connectionReturnedDefer = null;
 }
 
 /**
@@ -322,8 +323,9 @@ SyncApi.prototype.sync = function() {
             client.pushRules = result;
             getFilter(); // Now get the filter
         }, function(err) {
-            self._onConnectionReturned = getPushRules;
-            self._startKeepAlives();
+            self._startKeepAlives().done(() => {;
+                getPushRules();
+            });
             self._updateSyncState("ERROR", { error: err });
         });
     }
@@ -338,8 +340,9 @@ SyncApi.prototype.sync = function() {
             debuglog("Using existing filter ID %s", filterId);
             self._sync({ filterId: filterId });
         }, function(err) {
-            self._onConnectionReturned = getFilter;
-            self._startKeepAlives();
+            self._startKeepAlives().done(() => {
+                getFilter();
+            });
             self._updateSyncState("ERROR", { error: err });
         });
     }
@@ -372,7 +375,7 @@ SyncApi.prototype.stop = function() {
  * @return {boolean} True if this resulted in a request being retried.
  */
 SyncApi.prototype.retryImmediately = function() {
-    if (!this._onConnectionReturned) { return false; }
+    if (!this._connectionReturnedDefer) { return false; }
     this._startKeepAlives();
     return true;
 };
@@ -389,6 +392,10 @@ SyncApi.prototype._sync = function(syncOptions) {
 
     if (!this._running) {
         debuglog("Sync no longer running: exiting.");
+        if (self._connectionReturnedDefer) {
+            self._connectionReturnedDefer.reject();
+            self._connectionReturnedDefer = null;
+        }
         this._updateSyncState("STOPPED");
     }
 
@@ -479,6 +486,10 @@ SyncApi.prototype._sync = function(syncOptions) {
     }, function(err) {
         if (!self._running) {
             debuglog("Sync no longer running: exiting");
+            if (self._connectionReturnedDefer) {
+                self._connectionReturnedDefer.reject();
+                self._connectionReturnedDefer = null;
+            }
             return;
         }
         console.error("/sync error %s", err);
@@ -486,8 +497,9 @@ SyncApi.prototype._sync = function(syncOptions) {
 
         debuglog("Starting keep-alive");
         self._syncConnectionLost = true;
-        self._onConnectionReturned = self._sync.bind(self, syncOptions);
-        self._startKeepAlives();
+        self._startKeepAlives().done(() => {
+            self._sync(syncOptions);
+        });
         self._currentSyncRequest = null;
         self._updateSyncState("ERROR", { error: err });
     });
@@ -641,6 +653,10 @@ SyncApi.prototype._startKeepAlives = function() {
         clearTimeout(this._keepAliveTimer);
     }
     this._pokeKeepAlive();
+    if (!this._connectionReturnedDefer) {
+        this._connectionReturnedDefer = q.defer();
+    }
+    return this._connectionReturnedDefer.promise;
 };
 
 /**
@@ -650,9 +666,9 @@ SyncApi.prototype._pokeKeepAlive = function() {
     var self = this;
     function success() {
         clearTimeout(self._keepAliveTimer);
-        if (self._onConnectionReturned) {
-            self._onConnectionReturned();
-            self._onConnectionReturned = undefined;
+        if (self._connectionReturnedDefer) {
+            self._connectionReturnedDefer.resolve();
+            self._connectionReturnedDefer = null;
         }
     }