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/*
* Copyright (C) 2011 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 dalvik.system.CloseGuard;
import android.os.Looper;
import android.os.MessageQueue;
import android.util.Log;
import java.lang.ref.WeakReference;
/**
* Provides a low-level mechanism for an application to receive display events
* such as vertical sync.
*
* The display event receive is NOT thread safe. Moreover, its methods must only
* be called on the Looper thread to which it is attached.
*
* @hide
*/
public abstract class DisplayEventReceiver {
private static final String TAG = "DisplayEventReceiver";
private final CloseGuard mCloseGuard = CloseGuard.get();
private long mReceiverPtr;
// We keep a reference message queue object here so that it is not
// GC'd while the native peer of the receiver is using them.
private MessageQueue mMessageQueue;
private static native long nativeInit(WeakReference<DisplayEventReceiver> receiver,
MessageQueue messageQueue);
private static native void nativeDispose(long receiverPtr);
private static native void nativeScheduleVsync(long receiverPtr);
/**
* Creates a display event receiver.
*
* @param looper The looper to use when invoking callbacks.
*/
public DisplayEventReceiver(Looper looper) {
if (looper == null) {
throw new IllegalArgumentException("looper must not be null");
}
mMessageQueue = looper.getQueue();
mReceiverPtr = nativeInit(new WeakReference<DisplayEventReceiver>(this), mMessageQueue);
mCloseGuard.open("dispose");
}
@Override
protected void finalize() throws Throwable {
try {
dispose(true);
} finally {
super.finalize();
}
}
/**
* Disposes the receiver.
*/
public void dispose() {
dispose(false);
}
private void dispose(boolean finalized) {
if (mCloseGuard != null) {
if (finalized) {
mCloseGuard.warnIfOpen();
}
mCloseGuard.close();
}
if (mReceiverPtr != 0) {
nativeDispose(mReceiverPtr);
mReceiverPtr = 0;
}
mMessageQueue = null;
}
/**
* Called when a vertical sync pulse is received.
* The recipient should render a frame and then call {@link #scheduleVsync}
* to schedule the next vertical sync pulse.
*
* @param timestampNanos The timestamp of the pulse, in the {@link System#nanoTime()}
* timebase.
* @param builtInDisplayId The surface flinger built-in display id such as
* {@link SurfaceControl#BUILT_IN_DISPLAY_ID_MAIN}.
* @param frame The frame number. Increases by one for each vertical sync interval.
*/
public void onVsync(long timestampNanos, int builtInDisplayId, int frame) {
}
/**
* Called when a display hotplug event is received.
*
* @param timestampNanos The timestamp of the event, in the {@link System#nanoTime()}
* timebase.
* @param builtInDisplayId The surface flinger built-in display id such as
* {@link SurfaceControl#BUILT_IN_DISPLAY_ID_HDMI}.
* @param connected True if the display is connected, false if it disconnected.
*/
public void onHotplug(long timestampNanos, int builtInDisplayId, boolean connected) {
}
/**
* Schedules a single vertical sync pulse to be delivered when the next
* display frame begins.
*/
public void scheduleVsync() {
if (mReceiverPtr == 0) {
Log.w(TAG, "Attempted to schedule a vertical sync pulse but the display event "
+ "receiver has already been disposed.");
} else {
nativeScheduleVsync(mReceiverPtr);
}
}
// Called from native code.
@SuppressWarnings("unused")
private void dispatchVsync(long timestampNanos, int builtInDisplayId, int frame) {
onVsync(timestampNanos, builtInDisplayId, frame);
}
// Called from native code.
@SuppressWarnings("unused")
private void dispatchHotplug(long timestampNanos, int builtInDisplayId, boolean connected) {
onHotplug(timestampNanos, builtInDisplayId, connected);
}
}
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