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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License
     15  */
     16 
     17 package android.view;
     18 
     19 import android.os.Looper;
     20 
     21 /**
     22  * Similar to {@link InputEventReceiver}, but batches events to vsync boundaries when possible.
     23  * @hide
     24  */
     25 public class BatchedInputEventReceiver extends InputEventReceiver {
     26     Choreographer mChoreographer;
     27     private boolean mBatchedInputScheduled;
     28 
     29     public BatchedInputEventReceiver(
     30             InputChannel inputChannel, Looper looper, Choreographer choreographer) {
     31         super(inputChannel, looper);
     32         mChoreographer = choreographer;
     33     }
     34 
     35     @Override
     36     public void onBatchedInputEventPending() {
     37         scheduleBatchedInput();
     38     }
     39 
     40     @Override
     41     public void dispose() {
     42         unscheduleBatchedInput();
     43         super.dispose();
     44     }
     45 
     46     void doConsumeBatchedInput(long frameTimeNanos) {
     47         if (mBatchedInputScheduled) {
     48             mBatchedInputScheduled = false;
     49             if (consumeBatchedInputEvents(frameTimeNanos) && frameTimeNanos != -1) {
     50                 // If we consumed a batch here, we want to go ahead and schedule the
     51                 // consumption of batched input events on the next frame. Otherwise, we would
     52                 // wait until we have more input events pending and might get starved by other
     53                 // things occurring in the process. If the frame time is -1, however, then
     54                 // we're in a non-batching mode, so there's no need to schedule this.
     55                 scheduleBatchedInput();
     56             }
     57         }
     58     }
     59 
     60     private void scheduleBatchedInput() {
     61         if (!mBatchedInputScheduled) {
     62             mBatchedInputScheduled = true;
     63             mChoreographer.postCallback(Choreographer.CALLBACK_INPUT, mBatchedInputRunnable, null);
     64         }
     65     }
     66 
     67     private void unscheduleBatchedInput() {
     68         if (mBatchedInputScheduled) {
     69             mBatchedInputScheduled = false;
     70             mChoreographer.removeCallbacks(
     71                     Choreographer.CALLBACK_INPUT, mBatchedInputRunnable, null);
     72         }
     73     }
     74 
     75     private final class BatchedInputRunnable implements Runnable {
     76         @Override
     77         public void run() {
     78             doConsumeBatchedInput(mChoreographer.getFrameTimeNanos());
     79         }
     80     }
     81     private final BatchedInputRunnable mBatchedInputRunnable = new BatchedInputRunnable();
     82 }
     83