/*
* 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 android.hardware.display.DisplayManagerGlobal;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.SystemClock;
import android.os.SystemProperties;
import android.util.Log;
import android.util.TimeUtils;
import java.io.PrintWriter;
/**
* Coordinates the timing of animations, input and drawing.
* <p>
* The choreographer receives timing pulses (such as vertical synchronization)
* from the display subsystem then schedules work to occur as part of rendering
* the next display frame.
* </p><p>
* Applications typically interact with the choreographer indirectly using
* higher level abstractions in the animation framework or the view hierarchy.
* Here are some examples of things you can do using the higher-level APIs.
* </p>
* <ul>
* <li>To post an animation to be processed on a regular time basis synchronized with
* display frame rendering, use {@link android.animation.ValueAnimator#start}.</li>
* <li>To post a {@link Runnable} to be invoked once at the beginning of the next display
* frame, use {@link View#postOnAnimation}.</li>
* <li>To post a {@link Runnable} to be invoked once at the beginning of the next display
* frame after a delay, use {@link View#postOnAnimationDelayed}.</li>
* <li>To post a call to {@link View#invalidate()} to occur once at the beginning of the
* next display frame, use {@link View#postInvalidateOnAnimation()} or
* {@link View#postInvalidateOnAnimation(int, int, int, int)}.</li>
* <li>To ensure that the contents of a {@link View} scroll smoothly and are drawn in
* sync with display frame rendering, do nothing. This already happens automatically.
* {@link View#onDraw} will be called at the appropriate time.</li>
* </ul>
* <p>
* However, there are a few cases where you might want to use the functions of the
* choreographer directly in your application. Here are some examples.
* </p>
* <ul>
* <li>If your application does its rendering in a different thread, possibly using GL,
* or does not use the animation framework or view hierarchy at all
* and you want to ensure that it is appropriately synchronized with the display, then use
* {@link Choreographer#postFrameCallback}.</li>
* <li>... and that's about it.</li>
* </ul>
* <p>
* Each {@link Looper} thread has its own choreographer. Other threads can
* post callbacks to run on the choreographer but they will run on the {@link Looper}
* to which the choreographer belongs.
* </p>
*/
public final class Choreographer {
private static final String TAG = "Choreographer";
private static final boolean DEBUG = false;
// The default amount of time in ms between animation frames.
// When vsync is not enabled, we want to have some idea of how long we should
// wait before posting the next animation message. It is important that the
// default value be less than the true inter-frame delay on all devices to avoid
// situations where we might skip frames by waiting too long (we must compensate
// for jitter and hardware variations). Regardless of this value, the animation
// and display loop is ultimately rate-limited by how fast new graphics buffers can
// be dequeued.
private static final long DEFAULT_FRAME_DELAY = 10;
// The number of milliseconds between animation frames.
private static volatile long sFrameDelay = DEFAULT_FRAME_DELAY;
// Thread local storage for the choreographer.
private static final ThreadLocal<Choreographer> sThreadInstance =
new ThreadLocal<Choreographer>() {
@Override
protected Choreographer initialValue() {
Looper looper = Looper.myLooper();
if (looper == null) {
throw new IllegalStateException("The current thread must have a looper!");
}
return new Choreographer(looper);
}
};
// Enable/disable vsync for animations and drawing.
private static final boolean USE_VSYNC = SystemProperties.getBoolean(
"debug.choreographer.vsync", true);
// Enable/disable using the frame time instead of returning now.
private static final boolean USE_FRAME_TIME = SystemProperties.getBoolean(
"debug.choreographer.frametime", true);
// Set a limit to warn about skipped frames.
// Skipped frames imply jank.
private static final int SKIPPED_FRAME_WARNING_LIMIT = SystemProperties.getInt(
"debug.choreographer.skipwarning", 30);
private static final int MSG_DO_FRAME = 0;
private static final int MSG_DO_SCHEDULE_VSYNC = 1;
private static final int MSG_DO_SCHEDULE_CALLBACK = 2;
// All frame callbacks posted by applications have this token.
private static final Object FRAME_CALLBACK_TOKEN = new Object() {
public String toString() { return "FRAME_CALLBACK_TOKEN"; }
};
private final Object mLock = new Object();
private final Looper mLooper;
private final FrameHandler mHandler;
// The display event receiver can only be accessed by the looper thread to which
// it is attached. We take care to ensure that we post message to the looper
// if appropriate when interacting with the display event receiver.
private final FrameDisplayEventReceiver mDisplayEventReceiver;
private CallbackRecord mCallbackPool;
private final CallbackQueue[] mCallbackQueues;
private boolean mFrameScheduled;
private boolean mCallbacksRunning;
private long mLastFrameTimeNanos;
private long mFrameIntervalNanos;
/**
* Callback type: Input callback. Runs first.
* @hide
*/
public static final int CALLBACK_INPUT = 0;
/**
* Callback type: Animation callback. Runs before traversals.
* @hide
*/
public static final int CALLBACK_ANIMATION = 1;
/**
* Callback type: Traversal callback. Handles layout and draw. Runs last
* after all other asynchronous messages have been handled.
* @hide
*/
public static final int CALLBACK_TRAVERSAL = 2;
private static final int CALLBACK_LAST = CALLBACK_TRAVERSAL;
private Choreographer(Looper looper) {
mLooper = looper;
mHandler = new FrameHandler(looper);
mDisplayEventReceiver = USE_VSYNC ? new FrameDisplayEventReceiver(looper) : null;
mLastFrameTimeNanos = Long.MIN_VALUE;
mFrameIntervalNanos = (long)(1000000000 / getRefreshRate());
mCallbackQueues = new CallbackQueue[CALLBACK_LAST + 1];
for (int i = 0; i <= CALLBACK_LAST; i++) {
mCallbackQueues[i] = new CallbackQueue();
}
}
private static float getRefreshRate() {
DisplayInfo di = DisplayManagerGlobal.getInstance().getDisplayInfo(
Display.DEFAULT_DISPLAY);
return di.refreshRate;
}
/**
* Gets the choreographer for the calling thread. Must be called from
* a thread that already has a {@link android.os.Looper} associated with it.
*
* @return The choreographer for this thread.
* @throws IllegalStateException if the thread does not have a looper.
*/
public static Choreographer getInstance() {
return sThreadInstance.get();
}
/**
* The amount of time, in milliseconds, between each frame of the animation.
* <p>
* This is a requested time that the animation will attempt to honor, but the actual delay
* between frames may be different, depending on system load and capabilities. This is a static
* function because the same delay will be applied to all animations, since they are all
* run off of a single timing loop.
* </p><p>
* The frame delay may be ignored when the animation system uses an external timing
* source, such as the display refresh rate (vsync), to govern animations.
* </p>
*
* @return the requested time between frames, in milliseconds
* @hide
*/
public static long getFrameDelay() {
return sFrameDelay;
}
/**
* The amount of time, in milliseconds, between each frame of the animation.
* <p>
* This is a requested time that the animation will attempt to honor, but the actual delay
* between frames may be different, depending on system load and capabilities. This is a static
* function because the same delay will be applied to all animations, since they are all
* run off of a single timing loop.
* </p><p>
* The frame delay may be ignored when the animation system uses an external timing
* source, such as the display refresh rate (vsync), to govern animations.
* </p>
*
* @param frameDelay the requested time between frames, in milliseconds
* @hide
*/
public static void setFrameDelay(long frameDelay) {
sFrameDelay = frameDelay;
}
/**
* Subtracts typical frame delay time from a delay interval in milliseconds.
* <p>
* This method can be used to compensate for animation delay times that have baked
* in assumptions about the frame delay. For example, it's quite common for code to
* assume a 60Hz frame time and bake in a 16ms delay. When we call
* {@link #postAnimationCallbackDelayed} we want to know how long to wait before
* posting the animation callback but let the animation timer take care of the remaining
* frame delay time.
* </p><p>
* This method is somewhat conservative about how much of the frame delay it
* subtracts. It uses the same value returned by {@link #getFrameDelay} which by
* default is 10ms even though many parts of the system assume 16ms. Consequently,
* we might still wait 6ms before posting an animation callback that we want to run
* on the next frame, but this is much better than waiting a whole 16ms and likely
* missing the deadline.
* </p>
*
* @param delayMillis The original delay time including an assumed frame delay.
* @return The adjusted delay time with the assumed frame delay subtracted out.
* @hide
*/
public static long subtractFrameDelay(long delayMillis) {
final long frameDelay = sFrameDelay;
return delayMillis <= frameDelay ? 0 : delayMillis - frameDelay;
}
/**
* @return The refresh rate as the nanoseconds between frames
* @hide
*/
public long getFrameIntervalNanos() {
return mFrameIntervalNanos;
}
void dump(String prefix, PrintWriter writer) {
String innerPrefix = prefix + " ";
writer.print(prefix); writer.println("Choreographer:");
writer.print(innerPrefix); writer.print("mFrameScheduled=");
writer.println(mFrameScheduled);
writer.print(innerPrefix); writer.print("mLastFrameTime=");
writer.println(TimeUtils.formatUptime(mLastFrameTimeNanos / 1000000));
}
/**
* Posts a callback to run on the next frame.
* <p>
* The callback runs once then is automatically removed.
* </p>
*
* @param callbackType The callback type.
* @param action The callback action to run during the next frame.
* @param token The callback token, or null if none.
*
* @see #removeCallbacks
* @hide
*/
public void postCallback(int callbackType, Runnable action, Object token) {
postCallbackDelayed(callbackType, action, token, 0);
}
/**
* Posts a callback to run on the next frame after the specified delay.
* <p>
* The callback runs once then is automatically removed.
* </p>
*
* @param callbackType The callback type.
* @param action The callback action to run during the next frame after the specified delay.
* @param token The callback token, or null if none.
* @param delayMillis The delay time in milliseconds.
*
* @see #removeCallback
* @hide
*/
public void postCallbackDelayed(int callbackType,
Runnable action, Object token, long delayMillis) {
if (action == null) {
throw new IllegalArgumentException("action must not be null");
}
if (callbackType < 0 || callbackType > CALLBACK_LAST) {
throw new IllegalArgumentException("callbackType is invalid");
}
postCallbackDelayedInternal(callbackType, action, token, delayMillis);
}
private void postCallbackDelayedInternal(int callbackType,
Object action, Object token, long delayMillis) {
if (DEBUG) {
Log.d(TAG, "PostCallback: type=" + callbackType
+ ", action=" + action + ", token=" + token
+ ", delayMillis=" + delayMillis);
}
synchronized (mLock) {
final long now = SystemClock.uptimeMillis();
final long dueTime = now + delayMillis;
mCallbackQueues[callbackType].addCallbackLocked(dueTime, action, token);
if (dueTime <= now) {
scheduleFrameLocked(now);
} else {
Message msg = mHandler.obtainMessage(MSG_DO_SCHEDULE_CALLBACK, action);
msg.arg1 = callbackType;
msg.setAsynchronous(true);
mHandler.sendMessageAtTime(msg, dueTime);
}
}
}
/**
* Removes callbacks that have the specified action and token.
*
* @param callbackType The callback type.
* @param action The action property of the callbacks to remove, or null to remove
* callbacks with any action.
* @param token The token property of the callbacks to remove, or null to remove
* callbacks with any token.
*
* @see #postCallback
* @see #postCallbackDelayed
* @hide
*/
public void removeCallbacks(int callbackType, Runnable action, Object token) {
if (callbackType < 0 || callbackType > CALLBACK_LAST) {
throw new IllegalArgumentException("callbackType is invalid");
}
removeCallbacksInternal(callbackType, action, token);
}
private void removeCallbacksInternal(int callbackType, Object action, Object token) {
if (DEBUG) {
Log.d(TAG, "RemoveCallbacks: type=" + callbackType
+ ", action=" + action + ", token=" + token);
}
synchronized (mLock) {
mCallbackQueues[callbackType].removeCallbacksLocked(action, token);
if (action != null && token == null) {
mHandler.removeMessages(MSG_DO_SCHEDULE_CALLBACK, action);
}
}
}
/**
* Posts a frame callback to run on the next frame.
* <p>
* The callback runs once then is automatically removed.
* </p>
*
* @param callback The frame callback to run during the next frame.
*
* @see #postFrameCallbackDelayed
* @see #removeFrameCallback
*/
public void postFrameCallback(FrameCallback callback) {
postFrameCallbackDelayed(callback, 0);
}
/**
* Posts a frame callback to run on the next frame after the specified delay.
* <p>
* The callback runs once then is automatically removed.
* </p>
*
* @param callback The frame callback to run during the next frame.
* @param delayMillis The delay time in milliseconds.
*
* @see #postFrameCallback
* @see #removeFrameCallback
*/
public void postFrameCallbackDelayed(FrameCallback callback, long delayMillis) {
if (callback == null) {
throw new IllegalArgumentException("callback must not be null");
}
postCallbackDelayedInternal(CALLBACK_ANIMATION,
callback, FRAME_CALLBACK_TOKEN, delayMillis);
}
/**
* Removes a previously posted frame callback.
*
* @param callback The frame callback to remove.
*
* @see #postFrameCallback
* @see #postFrameCallbackDelayed
*/
public void removeFrameCallback(FrameCallback callback) {
if (callback == null) {
throw new IllegalArgumentException("callback must not be null");
}
removeCallbacksInternal(CALLBACK_ANIMATION, callback, FRAME_CALLBACK_TOKEN);
}
/**
* Gets the time when the current frame started.
* <p>
* This method provides the time in milliseconds when the frame started being rendered.
* The frame time provides a stable time base for synchronizing animations
* and drawing. It should be used instead of {@link SystemClock#uptimeMillis()}
* or {@link System#nanoTime()} for animations and drawing in the UI. Using the frame
* time helps to reduce inter-frame jitter because the frame time is fixed at the time
* the frame was scheduled to start, regardless of when the animations or drawing
* callback actually runs. All callbacks that run as part of rendering a frame will
* observe the same frame time so using the frame time also helps to synchronize effects
* that are performed by different callbacks.
* </p><p>
* Please note that the framework already takes care to process animations and
* drawing using the frame time as a stable time base. Most applications should
* not need to use the frame time information directly.
* </p><p>
* This method should only be called from within a callback.
* </p>
*
* @return The frame start time, in the {@link SystemClock#uptimeMillis()} time base.
*
* @throws IllegalStateException if no frame is in progress.
* @hide
*/
public long getFrameTime() {
return getFrameTimeNanos() / TimeUtils.NANOS_PER_MS;
}
/**
* Same as {@link #getFrameTime()} but with nanosecond precision.
*
* @return The frame start time, in the {@link System#nanoTime()} time base.
*
* @throws IllegalStateException if no frame is in progress.
* @hide
*/
public long getFrameTimeNanos() {
synchronized (mLock) {
if (!mCallbacksRunning) {
throw new IllegalStateException("This method must only be called as "
+ "part of a callback while a frame is in progress.");
}
return USE_FRAME_TIME ? mLastFrameTimeNanos : System.nanoTime();
}
}
private void scheduleFrameLocked(long now) {
if (!mFrameScheduled) {
mFrameScheduled = true;
if (USE_VSYNC) {
if (DEBUG) {
Log.d(TAG, "Scheduling next frame on vsync.");
}
// If running on the Looper thread, then schedule the vsync immediately,
// otherwise post a message to schedule the vsync from the UI thread
// as soon as possible.
if (isRunningOnLooperThreadLocked()) {
scheduleVsyncLocked();
} else {
Message msg = mHandler.obtainMessage(MSG_DO_SCHEDULE_VSYNC);
msg.setAsynchronous(true);
mHandler.sendMessageAtFrontOfQueue(msg);
}
} else {
final long nextFrameTime = Math.max(
mLastFrameTimeNanos / TimeUtils.NANOS_PER_MS + sFrameDelay, now);
if (DEBUG) {
Log.d(TAG, "Scheduling next frame in " + (nextFrameTime - now) + " ms.");
}
Message msg = mHandler.obtainMessage(MSG_DO_FRAME);
msg.setAsynchronous(true);
mHandler.sendMessageAtTime(msg, nextFrameTime);
}
}
}
void doFrame(long frameTimeNanos, int frame) {
final long startNanos;
synchronized (mLock) {
if (!mFrameScheduled) {
return; // no work to do
}
startNanos = System.nanoTime();
final long jitterNanos = startNanos - frameTimeNanos;
if (jitterNanos >= mFrameIntervalNanos) {
final long skippedFrames = jitterNanos / mFrameIntervalNanos;
if (skippedFrames >= SKIPPED_FRAME_WARNING_LIMIT) {
Log.i(TAG, "Skipped " + skippedFrames + " frames! "
+ "The application may be doing too much work on its main thread.");
}
final long lastFrameOffset = jitterNanos % mFrameIntervalNanos;
if (DEBUG) {
Log.d(TAG, "Missed vsync by " + (jitterNanos * 0.000001f) + " ms "
+ "which is more than the frame interval of "
+ (mFrameIntervalNanos * 0.000001f) + " ms! "
+ "Skipping " + skippedFrames + " frames and setting frame "
+ "time to " + (lastFrameOffset * 0.000001f) + " ms in the past.");
}
frameTimeNanos = startNanos - lastFrameOffset;
}
if (frameTimeNanos < mLastFrameTimeNanos) {
if (DEBUG) {
Log.d(TAG, "Frame time appears to be going backwards. May be due to a "
+ "previously skipped frame. Waiting for next vsync.");
}
scheduleVsyncLocked();
return;
}
mFrameScheduled = false;
mLastFrameTimeNanos = frameTimeNanos;
}
doCallbacks(Choreographer.CALLBACK_INPUT, frameTimeNanos);
doCallbacks(Choreographer.CALLBACK_ANIMATION, frameTimeNanos);
doCallbacks(Choreographer.CALLBACK_TRAVERSAL, frameTimeNanos);
if (DEBUG) {
final long endNanos = System.nanoTime();
Log.d(TAG, "Frame " + frame + ": Finished, took "
+ (endNanos - startNanos) * 0.000001f + " ms, latency "
+ (startNanos - frameTimeNanos) * 0.000001f + " ms.");
}
}
void doCallbacks(int callbackType, long frameTimeNanos) {
CallbackRecord callbacks;
synchronized (mLock) {
// We use "now" to determine when callbacks become due because it's possible
// for earlier processing phases in a frame to post callbacks that should run
// in a following phase, such as an input event that causes an animation to start.
final long now = SystemClock.uptimeMillis();
callbacks = mCallbackQueues[callbackType].extractDueCallbacksLocked(now);
if (callbacks == null) {
return;
}
mCallbacksRunning = true;
}
try {
for (CallbackRecord c = callbacks; c != null; c = c.next) {
if (DEBUG) {
Log.d(TAG, "RunCallback: type=" + callbackType
+ ", action=" + c.action + ", token=" + c.token
+ ", latencyMillis=" + (SystemClock.uptimeMillis() - c.dueTime));
}
c.run(frameTimeNanos);
}
} finally {
synchronized (mLock) {
mCallbacksRunning = false;
do {
final CallbackRecord next = callbacks.next;
recycleCallbackLocked(callbacks);
callbacks = next;
} while (callbacks != null);
}
}
}
void doScheduleVsync() {
synchronized (mLock) {
if (mFrameScheduled) {
scheduleVsyncLocked();
}
}
}
void doScheduleCallback(int callbackType) {
synchronized (mLock) {
if (!mFrameScheduled) {
final long now = SystemClock.uptimeMillis();
if (mCallbackQueues[callbackType].hasDueCallbacksLocked(now)) {
scheduleFrameLocked(now);
}
}
}
}
private void scheduleVsyncLocked() {
mDisplayEventReceiver.scheduleVsync();
}
private boolean isRunningOnLooperThreadLocked() {
return Looper.myLooper() == mLooper;
}
private CallbackRecord obtainCallbackLocked(long dueTime, Object action, Object token) {
CallbackRecord callback = mCallbackPool;
if (callback == null) {
callback = new CallbackRecord();
} else {
mCallbackPool = callback.next;
callback.next = null;
}
callback.dueTime = dueTime;
callback.action = action;
callback.token = token;
return callback;
}
private void recycleCallbackLocked(CallbackRecord callback) {
callback.action = null;
callback.token = null;
callback.next = mCallbackPool;
mCallbackPool = callback;
}
/**
* Implement this interface to receive a callback when a new display frame is
* being rendered. The callback is invoked on the {@link Looper} thread to
* which the {@link Choreographer} is attached.
*/
public interface FrameCallback {
/**
* Called when a new display frame is being rendered.
* <p>
* This method provides the time in nanoseconds when the frame started being rendered.
* The frame time provides a stable time base for synchronizing animations
* and drawing. It should be used instead of {@link SystemClock#uptimeMillis()}
* or {@link System#nanoTime()} for animations and drawing in the UI. Using the frame
* time helps to reduce inter-frame jitter because the frame time is fixed at the time
* the frame was scheduled to start, regardless of when the animations or drawing
* callback actually runs. All callbacks that run as part of rendering a frame will
* observe the same frame time so using the frame time also helps to synchronize effects
* that are performed by different callbacks.
* </p><p>
* Please note that the framework already takes care to process animations and
* drawing using the frame time as a stable time base. Most applications should
* not need to use the frame time information directly.
* </p>
*
* @param frameTimeNanos The time in nanoseconds when the frame started being rendered,
* in the {@link System#nanoTime()} timebase. Divide this value by {@code 1000000}
* to convert it to the {@link SystemClock#uptimeMillis()} time base.
*/
public void doFrame(long frameTimeNanos);
}
private final class FrameHandler extends Handler {
public FrameHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_DO_FRAME:
doFrame(System.nanoTime(), 0);
break;
case MSG_DO_SCHEDULE_VSYNC:
doScheduleVsync();
break;
case MSG_DO_SCHEDULE_CALLBACK:
doScheduleCallback(msg.arg1);
break;
}
}
}
private final class FrameDisplayEventReceiver extends DisplayEventReceiver
implements Runnable {
private boolean mHavePendingVsync;
private long mTimestampNanos;
private int mFrame;
public FrameDisplayEventReceiver(Looper looper) {
super(looper);
}
@Override
public void onVsync(long timestampNanos, int builtInDisplayId, int frame) {
// Ignore vsync from secondary display.
// This can be problematic because the call to scheduleVsync() is a one-shot.
// We need to ensure that we will still receive the vsync from the primary
// display which is the one we really care about. Ideally we should schedule
// vsync for a particular display.
// At this time Surface Flinger won't send us vsyncs for secondary displays
// but that could change in the future so let's log a message to help us remember
// that we need to fix this.
if (builtInDisplayId != SurfaceControl.BUILT_IN_DISPLAY_ID_MAIN) {
Log.d(TAG, "Received vsync from secondary display, but we don't support "
+ "this case yet. Choreographer needs a way to explicitly request "
+ "vsync for a specific display to ensure it doesn't lose track "
+ "of its scheduled vsync.");
scheduleVsync();
return;
}
// Post the vsync event to the Handler.
// The idea is to prevent incoming vsync events from completely starving
// the message queue. If there are no messages in the queue with timestamps
// earlier than the frame time, then the vsync event will be processed immediately.
// Otherwise, messages that predate the vsync event will be handled first.
long now = System.nanoTime();
if (timestampNanos > now) {
Log.w(TAG, "Frame time is " + ((timestampNanos - now) * 0.000001f)
+ " ms in the future! Check that graphics HAL is generating vsync "
+ "timestamps using the correct timebase.");
timestampNanos = now;
}
if (mHavePendingVsync) {
Log.w(TAG, "Already have a pending vsync event. There should only be "
+ "one at a time.");
} else {
mHavePendingVsync = true;
}
mTimestampNanos = timestampNanos;
mFrame = frame;
Message msg = Message.obtain(mHandler, this);
msg.setAsynchronous(true);
mHandler.sendMessageAtTime(msg, timestampNanos / TimeUtils.NANOS_PER_MS);
}
@Override
public void run() {
mHavePendingVsync = false;
doFrame(mTimestampNanos, mFrame);
}
}
private static final class CallbackRecord {
public CallbackRecord next;
public long dueTime;
public Object action; // Runnable or FrameCallback
public Object token;
public void run(long frameTimeNanos) {
if (token == FRAME_CALLBACK_TOKEN) {
((FrameCallback)action).doFrame(frameTimeNanos);
} else {
((Runnable)action).run();
}
}
}
private final class CallbackQueue {
private CallbackRecord mHead;
public boolean hasDueCallbacksLocked(long now) {
return mHead != null && mHead.dueTime <= now;
}
public CallbackRecord extractDueCallbacksLocked(long now) {
CallbackRecord callbacks = mHead;
if (callbacks == null || callbacks.dueTime > now) {
return null;
}
CallbackRecord last = callbacks;
CallbackRecord next = last.next;
while (next != null) {
if (next.dueTime > now) {
last.next = null;
break;
}
last = next;
next = next.next;
}
mHead = next;
return callbacks;
}
public void addCallbackLocked(long dueTime, Object action, Object token) {
CallbackRecord callback = obtainCallbackLocked(dueTime, action, token);
CallbackRecord entry = mHead;
if (entry == null) {
mHead = callback;
return;
}
if (dueTime < entry.dueTime) {
callback.next = entry;
mHead = callback;
return;
}
while (entry.next != null) {
if (dueTime < entry.next.dueTime) {
callback.next = entry.next;
break;
}
entry = entry.next;
}
entry.next = callback;
}
public void removeCallbacksLocked(Object action, Object token) {
CallbackRecord predecessor = null;
for (CallbackRecord callback = mHead; callback != null;) {
final CallbackRecord next = callback.next;
if ((action == null || callback.action == action)
&& (token == null || callback.token == token)) {
if (predecessor != null) {
predecessor.next = next;
} else {
mHead = next;
}
recycleCallbackLocked(callback);
} else {
predecessor = callback;
}
callback = next;
}
}
}
}
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