Add synchronization to DeferredBindRunnables

Seems that on occasion the list is being iterated on while being
modified.  To fix this added synchronization to all modifications
to the list as well as iterating on a copy of the list to cut
down on time holding the lock.

Bug: 12885709
Change-Id: I4287bdedbeb8e438b49c1f79b44819a752c28a69

1 files changed, 25 insertions, 8 deletions

diff --git a/src/com/android/launcher3/LauncherModel.java b/src/com/android/launcher3/LauncherModel.java
index e5eca625b..0efd1728f 100644
--- a/src/com/android/launcher3/LauncherModel.java
+++ b/src/com/android/launcher3/LauncherModel.java
@@ -498,7 +498,9 @@ public class LauncherModel extends BroadcastReceiver {
         }
 
         // Clear any deferred bind runnables
-        mDeferredBindRunnables.clear();
+        synchronized (mDeferredBindRunnables) {
+            mDeferredBindRunnables.clear();
+        }
         // Remove any queued bind runnables
         mHandler.cancelAllRunnablesOfType(MAIN_THREAD_BINDING_RUNNABLE);
         // Unbind all the workspace items
@@ -1315,7 +1317,9 @@ public class LauncherModel extends BroadcastReceiver {
 
             // Clear any deferred bind-runnables from the synchronized load process
             // We must do this before any loading/binding is scheduled below.
-            mDeferredBindRunnables.clear();
+            synchronized (mDeferredBindRunnables) {
+                mDeferredBindRunnables.clear();
+            }
 
             // Don't bother to start the thread if we know it's not going to do anything
             if (mCallbacks != null && mCallbacks.get() != null) {
@@ -1337,10 +1341,15 @@ public class LauncherModel extends BroadcastReceiver {
     void bindRemainingSynchronousPages() {
         // Post the remaining side pages to be loaded
         if (!mDeferredBindRunnables.isEmpty()) {
-            for (final Runnable r : mDeferredBindRunnables) {
+            Runnable[] deferredBindRunnables = null;
+            synchronized (mDeferredBindRunnables) {
+                deferredBindRunnables = mDeferredBindRunnables.toArray(
+                        new Runnable[mDeferredBindRunnables.size()]);
+                mDeferredBindRunnables.clear();
+            }
+            for (final Runnable r : deferredBindRunnables) {
                 mHandler.post(r, MAIN_THREAD_BINDING_RUNNABLE);
             }
-            mDeferredBindRunnables.clear();
         }
     }
 
@@ -2367,7 +2376,9 @@ public class LauncherModel extends BroadcastReceiver {
                     }
                 };
                 if (postOnMainThread) {
-                    deferredBindRunnables.add(r);
+                    synchronized (deferredBindRunnables) {
+                        deferredBindRunnables.add(r);
+                    }
                 } else {
                     runOnMainThread(r, MAIN_THREAD_BINDING_RUNNABLE);
                 }
@@ -2384,7 +2395,9 @@ public class LauncherModel extends BroadcastReceiver {
                     }
                 };
                 if (postOnMainThread) {
-                    deferredBindRunnables.add(r);
+                    synchronized (deferredBindRunnables) {
+                        deferredBindRunnables.add(r);
+                    }
                 } else {
                     runOnMainThread(r, MAIN_THREAD_BINDING_RUNNABLE);
                 }
@@ -2506,7 +2519,9 @@ public class LauncherModel extends BroadcastReceiver {
 
             // Load all the remaining pages (if we are loading synchronously, we want to defer this
             // work until after the first render)
-            mDeferredBindRunnables.clear();
+            synchronized (mDeferredBindRunnables) {
+                mDeferredBindRunnables.clear();
+            }
             bindWorkspaceItems(oldCallbacks, otherWorkspaceItems, otherAppWidgets, otherFolders,
                     (isLoadingSynchronously ? mDeferredBindRunnables : null));
 
@@ -2528,7 +2543,9 @@ public class LauncherModel extends BroadcastReceiver {
                 }
             };
             if (isLoadingSynchronously) {
-                mDeferredBindRunnables.add(r);
+                synchronized (mDeferredBindRunnables) {
+                    mDeferredBindRunnables.add(r);
+                }
             } else {
                 runOnMainThread(r, MAIN_THREAD_BINDING_RUNNABLE);
             }