Batch ACTION_MOVE events to vsync boundries when resizing task

- Created helper class BatchedInputEventReceiver for batching
ACTION_MOVE events to vsync boundries.
- Switched TaskPositioner to use new helper class for input events
so we reduce the number of input events we process per vsync.

Bug: 24375616
Change-Id: I4ee27949b956784fb89d8f190497e4765522c9d3

1 files changed, 82 insertions, 0 deletions

diff --git a/core/java/android/view/BatchedInputEventReceiver.java b/core/java/android/view/BatchedInputEventReceiver.java
new file mode 100644
index 000000000000..b1d28e000bc8
--- /dev/null
+++ b/core/java/android/view/BatchedInputEventReceiver.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2015 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 android.view;
+
+import android.os.Looper;
+
+/**
+ * Similar to {@link InputEventReceiver}, but batches events to vsync boundaries when possible.
+ * @hide
+ */
+public class BatchedInputEventReceiver extends InputEventReceiver {
+    Choreographer mChoreographer;
+    private boolean mBatchedInputScheduled;
+
+    public BatchedInputEventReceiver(
+            InputChannel inputChannel, Looper looper, Choreographer choreographer) {
+        super(inputChannel, looper);
+        mChoreographer = choreographer;
+    }
+
+    @Override
+    public void onBatchedInputEventPending() {
+        scheduleBatchedInput();
+    }
+
+    @Override
+    public void dispose() {
+        unscheduleBatchedInput();
+        super.dispose();
+    }
+
+    void doConsumeBatchedInput(long frameTimeNanos) {
+        if (mBatchedInputScheduled) {
+            mBatchedInputScheduled = false;
+            if (consumeBatchedInputEvents(frameTimeNanos) && frameTimeNanos != -1) {
+                // If we consumed a batch here, we want to go ahead and schedule the
+                // consumption of batched input events on the next frame. Otherwise, we would
+                // wait until we have more input events pending and might get starved by other
+                // things occurring in the process. If the frame time is -1, however, then
+                // we're in a non-batching mode, so there's no need to schedule this.
+                scheduleBatchedInput();
+            }
+        }
+    }
+
+    private void scheduleBatchedInput() {
+        if (!mBatchedInputScheduled) {
+            mBatchedInputScheduled = true;
+            mChoreographer.postCallback(Choreographer.CALLBACK_INPUT, mBatchedInputRunnable, null);
+        }
+    }
+
+    private void unscheduleBatchedInput() {
+        if (mBatchedInputScheduled) {
+            mBatchedInputScheduled = false;
+            mChoreographer.removeCallbacks(
+                    Choreographer.CALLBACK_INPUT, mBatchedInputRunnable, null);
+        }
+    }
+
+    private final class BatchedInputRunnable implements Runnable {
+        @Override
+        public void run() {
+            doConsumeBatchedInput(mChoreographer.getFrameTimeNanos());
+        }
+    }
+    private final BatchedInputRunnable mBatchedInputRunnable = new BatchedInputRunnable();
+}