PowerManagerServices关于WackLock的acquire和release的流程
常见的我们在app上写入亮屏和灭屏操作如下
PowerManager pm = (PowerManager)getSystemService(POWER_SERVICE);
wacklock = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "cn");
wacklock.acquire(); //设置保持唤醒
if(wacklock != null)
{
wacklock.release();
}
接下来我们具体分析下代码流程.
Step 1：
frameworks\base\core\java\android\os\PowerManager.java
public void acquire() {
synchronized (mToken) {
acquireLocked();
}
}
/**
* Acquires the wake lock with a timeout.
*
* Ensures that the device is on at the level requested when
* the wake lock was created. The lock will be released after the given timeout
* expires.
*
*
* @param timeout The timeout after which to release the wake lock, in milliseconds.
*/
public void acquire(long timeout) {
synchronized (mToken) {
acquireLocked();
mHandler.postDelayed(mReleaser, timeout);
}
}
private void acquireLocked() {
if (!mRefCounted || mCount++ == 0) {
// Do this even if the wake lock is already thought to be held (mHeld == true)
// because non-reference counted wake locks are not always properly released.
// For example, the keyguard's wake lock might be forcibly released by the
// power manager without the keyguard knowing. A subsequent call to acquire
// should immediately acquire the wake lock once again despite never having
// been explicitly released by the keyguard.
mHandler.removeCallbacks(mReleaser);
Trace.asyncTraceBegin(Trace.TRACE_TAG_POWER, mTraceName, 0);
try {
mService.acquireWakeLock(mToken, mFlags, mTag, mPackageName, mWorkSource,
mHistoryTag);
} catch (RemoteException e) {
}
mHeld = true;
}
}
/**
* Releases the wake lock.
*
* This method releases your claim to the CPU or screen being on.
* The screen may turn off shortly after you release the wake lock, or it may
* not if there are other wake locks still held.
*
*/
public void release() {
release(0);
}
/**
* Releases the wake lock with flags to modify the release behavior.
*
* This method releases your claim to the CPU or screen being on.
* The screen may turn off shortly after you release the wake lock, or it may
* not if there are other wake locks still held.
*
*
* @param flags Combination of flag values to modify the release behavior.
* Currently only {@link #RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY} is supported.
* Passing 0 is equivalent to calling {@link #release()}.
*/
public void release(int flags) {
synchronized (mToken) {
if (!mRefCounted || --mCount == 0) {
mHandler.removeCallbacks(mReleaser);
if (mHeld) {
Trace.asyncTraceEnd(Trace.TRACE_TAG_POWER, mTraceName, 0);
try {
mService.releaseWakeLock(mToken, flags);
} catch (RemoteException e) {
}
mHeld = false;
}
}
if (mCount < 0) {
throw new RuntimeException("WakeLock under-locked " + mTag);
}
}
}
Step 2:
frameworks\base\services\core\java\com\android\server\power\PowerManagerService.java
用于在app层调用最新会调用到PowerManagerService层中的acquireWackLock
public void acquireWakeLock(IBinder lock, int flags, String tag, String packageName,
WorkSource ws, String historyTag) {
if (lock == null) {
throw new IllegalArgumentException("lock must not be null");
}
if (packageName == null) {
throw new IllegalArgumentException("packageName must not be null");
}
PowerManager.validateWakeLockParameters(flags, tag);
mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WAKE_LOCK, null);
if ((flags & PowerManager.DOZE_WAKE_LOCK) != 0) {
mContext.enforceCallingOrSelfPermission(
android.Manifest.permission.DEVICE_POWER, null);
}
if (ws != null && ws.size() != 0) {
mContext.enforceCallingOrSelfPermission(
android.Manifest.permission.UPDATE_DEVICE_STATS, null);
} else {
ws = null;
}
final int uid = Binder.getCallingUid();
final int pid = Binder.getCallingPid();
final long ident = Binder.clearCallingIdentity();
try {
acquireWakeLockInternal(lock, flags, tag, packageName, ws, historyTag, uid, pid);
} finally {
Binder.restoreCallingIdentity(ident);
}
} //acquireWakeLockInternal主要作用是创建WakeLock对象并且加入到mWakeLocks列表中，这个列表包含了所有的WackLock对象
private void acquireWakeLockInternal(IBinder lock, int flags, String tag, String packageName,
WorkSource ws, String historyTag, int uid, int pid) {
synchronized (mLock) {
if (DEBUG_SPEW) {
Slog.d(TAG, "acquireWakeLockInternal: lock=" + Objects.hashCode(lock)
+ ", flags=0x" + Integer.toHexString(flags)
+ ", tag=\"" + tag + "\", ws=" + ws + ", uid=" + uid + ", pid=" + pid);
}
//xionghui add start
boolean isScreenOn = needDisplaySuspendBlockerLocked();
if(isSkipByPkgOrTag(packageName, tag) && !isScreenOn && (!isNetworkEnable()||!isGmsConnected())){
Slog.d("xionghui","xionghui acquireWakeLockInternal return packageName="+packageName+" tag="+tag);
return;
}
//xionghui add end
WakeLock wakeLock;
int index = findWakeLockIndexLocked(lock);//检查这个锁是否存在
boolean notifyAcquire;
if (index >= 0) {//index >= 表示已经存在，不存在则创建新的wackLock
wakeLock = mWakeLocks.get(index);
if (!wakeLock.hasSameProperties(flags, tag, ws, uid, pid)) {
// Update existing wake lock. This shouldn't happen but is harmless.
notifyWakeLockChangingLocked(wakeLock, flags, tag, packageName,
uid, pid, ws, historyTag);
wakeLock.updateProperties(flags, tag, packageName, ws, historyTag, uid, pid);
}
notifyAcquire = false;
} else {
wakeLock = new WakeLock(lock, flags, tag, packageName, ws, historyTag, uid, pid);
try {
lock.linkToDeath(wakeLock, 0);
} catch (RemoteException ex) {
throw new IllegalArgumentException("Wake lock is already dead.");
}
mWakeLocks.add(wakeLock);//将创建的WackLock对象加入到mWakeLocks
setWakeLockDisabledStateLocked(wakeLock);
notifyAcquire = true;
wakeLock.mActiveSince = SystemClock.uptimeMillis();
}
applyWakeLockFlagsOnAcquireLocked(wakeLock, uid);//看是否需要唤醒设备
mDirty |= DIRTY_WAKE_LOCKS;
updatePowerStateLocked();//更新手机电源状态
if (notifyAcquire) {
// This needs to be done last so we are sure we have acquired the
// kernel wake lock. Otherwise we have a race where the system may
// go to sleep between the time we start the accounting in battery
// stats and when we actually get around to telling the kernel to
// stay awake.
notifyWakeLockAcquiredLocked(wakeLock);
}
}
}同理
用于在app层调用最新会调用到PowerManagerService层中的releaseWackLock
@Override // Binder call
public void releaseWakeLock(IBinder lock, int flags) {
if (lock == null) {
throw new IllegalArgumentException("lock must not be null");
}
mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WAKE_LOCK, null);
final long ident = Binder.clearCallingIdentity();
try {
releaseWakeLockInternal(lock, flags);
} finally {
Binder.restoreCallingIdentity(ident);
}
} private void releaseWakeLockInternal(IBinder lock, int flags) {
synchronized (mLock) {
int index = findWakeLockIndexLocked(lock);
if (index < 0) {
if (DEBUG_SPEW) {
Slog.d(TAG, "releaseWakeLockInternal: lock=" + Objects.hashCode(lock)
+ " [not found], flags=0x" + Integer.toHexString(flags));
}
return;
}
WakeLock wakeLock = mWakeLocks.get(index);
wakeLock.mTotalTime = SystemClock.uptimeMillis() - wakeLock.mActiveSince;
if (DEBUG_SPEW) {
Slog.d(TAG, "releaseWakeLockInternal: lock=" + Objects.hashCode(lock)
+ " [" + wakeLock.mTag + "], flags=0x" + Integer.toHexString(flags) + ", total_time=" + wakeLock.mTotalTime + "ms");
}
if ((flags & PowerManager.RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY) != 0) {
mRequestWaitForNegativeProximity = true;
}
wakeLock.mLock.unlinkToDeath(wakeLock, 0);
removeWakeLockLocked(wakeLock, index);
}
至于
updatePowerStateLocked 功能我们参考
PowerManagerService开机启动关于WackLock处理的相关流程