1 files changed, 71 insertions, 0 deletions
diff --git a/src/com/android/launcher3/util/LooperIdleLock.java b/src/com/android/launcher3/util/LooperIdleLock.java
new file mode 100644
index 000000000..35cac14e3
--- /dev/null
+++ b/src/com/android/launcher3/util/LooperIdleLock.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3.util;
+
+import android.os.Looper;
+import android.os.MessageQueue;
+
+import com.android.launcher3.Utilities;
+
+/**
+ * Utility class to block execution until the UI looper is idle.
+ */
+public class LooperIdleLock implements MessageQueue.IdleHandler, Runnable {
+
+    private final Object mLock;
+
+    private boolean mIsLocked;
+
+    public LooperIdleLock(Object lock, Looper looper) {
+        mLock = lock;
+        mIsLocked = true;
+        if (Utilities.ATLEAST_MARSHMALLOW) {
+            looper.getQueue().addIdleHandler(this);
+        } else {
+            // Looper.myQueue() only gives the current queue. Move the execution to the UI thread
+            // so that the IdleHandler is attached to the correct message queue.
+            new LooperExecutor(looper).execute(this);
+        }
+    }
+
+    @Override
+    public void run() {
+        Looper.myQueue().addIdleHandler(this);
+    }
+
+    @Override
+    public boolean queueIdle() {
+        synchronized (mLock) {
+            mIsLocked = false;
+            mLock.notify();
+        }
+        return false;
+    }
+
+    public boolean awaitLocked(long ms) {
+        if (mIsLocked) {
+            try {
+                // Just in case mFlushingWorkerThread changes but we aren't woken up,
+                // wait no longer than 1sec at a time
+                mLock.wait(ms);
+            } catch (InterruptedException ex) {
+                // Ignore
+            }
+        }
+        return mIsLocked;
+    }
+}