从android的Surface Flinger服务启动分析知道,开机动画是在SurfaceFlinger实例通过调用startBootAnim()启动的。
下面我们就一起学习BootAnim是如何启动和结束的,我精读代码前都喜欢先描出框架图,以此图为基础再去研读会达到事半功倍的效果。好吧,直接上图。
内核起来后会启动第一个进程,即init进程。
init进程会根据init.rc配置启动surfaceflinger进程。
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- service surfaceflinger /system/bin/surfaceflinger
- class main
- user system
- group graphics drmrpc
- onrestart restart zygote
surfaceflinger进程便启动了,跟着就会跑进程的main()函数。
frameworks/native/services/surfaceflinger/main_surfaceflinger.cpp
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- int main(int argc, char** argv) {
- ....
- // instantiate surfaceflinger
- sp
flinger = new SurfaceFlinger();//创建surfaceflinger服务实例 - ....
- flinger->init();
- // publish surface flinger
- sp
sm(defaultServiceManager()); - sm->addService(String16(SurfaceFlinger::getServiceName()), flinger, false);//注册到service manager里
- // run in this thread
- flinger->run();//开跑
- return 0;
- }
首先new一个SurfaceFlinger实例,然后init,然后run
frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp
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- void SurfaceFlinger::init() {
- ALOGI( "SurfaceFlinger's main thread ready to run. "
- "Initializing graphics H/W...");
- .....
- // start boot animation
- startBootAnim();//开始播放动画
- }
初始化graphics之后,就调用startBootAnim()播放开机动画。
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- void SurfaceFlinger::startBootAnim() {
- // start boot animation
- mBootFinished = false;
- property_set("service.bootanim.exit", "0");//这个会有bootanimation进程周期检测,=1退出动画
- property_set("ctl.start", "bootanim");//通过ctl.start命令启动bootanim
- }
把service.bootanim.exit属性设为0,这个属性bootanimation进程里会周期检查,=1时就退出动画,这里=0表示要播放动画。
后面通过ctl.start的命令启动bootanim进程,动画就开始播放了。
下面来到bootanimation的实现
frameworks/base/cmds/bootanimation/bootanimation_main.cpp
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- int main(int argc, char** argv)
- {
- sp
proc(ProcessState::self()); - ProcessState::self()->startThreadPool();
- // create the boot animation object
- sp
boot = new BootAnimation();//创建BootAnimation实例 - IPCThreadState::self()->joinThreadPool();//binder线程池,与surfaceflinger通信用的。
- }
- return 0;
- }
new一个BootAnimation实例,然后建个binder线程池,因为BootAnimation在显示动画时要与SurfaceFlinger服务进程通信,所以要启个binder线程池。
frameworks/base/cmds/bootanimation/BootAnimation.cpp
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- BootAnimation::BootAnimation() : Thread(false)
- {
- mSession = new SurfaceComposerClient();//创建一个对象
- }
创建实例时,构造函数就会被调用,new一个SurfaceComposerClient实例,他是用来与surfaceflinger通信的
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- void BootAnimation::onFirstRef() {
- status_t err = mSession->linkToComposerDeath(this);//注册surfaceflinger死亡消息的通知书
- ALOGE_IF(err, "linkToComposerDeath failed (%s) ", strerror(-err));
- if (err == NO_ERROR) {
- run("BootAnimation", PRIORITY_DISPLAY);//开跑
- }
- }
linkTocomposerDeath的作用是当surfaceflinger死掉是,BootAnimation就会得到通知。
如下,收到通知后就退出动画了,因为surfaceflinger都挂掉了,播放不了了。
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- void BootAnimation::binderDied(const wp
& who) - {
- // woah, surfaceflinger died!
- ALOGD("SurfaceFlinger died, exiting...");
- // calling requestExit() is not enough here because the Surface code
- // might be blocked on a condition variable that will never be updated.
- kill( getpid(), SIGKILL );//收到surfaceflinger死亡的消息,好吧自己也跟着去了。
- requestExit();
- }
另一个函数run()在BootAnimation的父类Thead里,用来创建一个线程并跑起来。
父类
system/core/libutils/Threads.cpp
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- status_t Thread::run(const char* name, int32_t priority, size_t stack)
- {
- ...
- if (mCanCallJava) {
- res = createThreadEtc(_threadLoop,//创建线程
- this, name, priority, stack, &mThread);
- } else {
- res = androidCreateRawThreadEtc(_threadLoop,
- this, name, priority, stack, &mThread);
- }
- ....
- }
创建_threadLoop线程
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- int Thread::_threadLoop(void* user)
- {
- ....
- do {
- bool result;
- if (first) {
- first = false;
- self->mStatus = self->readyToRun();//这个函数被bootanimation重写了
- result = (self->mStatus == NO_ERROR);
- if (result && !self->exitPending()) {
- ...
- result = self->threadLoop();//这个函数被bootanimation重写了
- }
- } else {
- result = self->threadLoop();
- }
- ...
- return 0;
- }
readyToRun函数实现
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- status_t BootAnimation::readyToRun() {
- mAssets.addDefaultAssets();
- sp
dtoken(SurfaceComposerClient::getBuiltInDisplay( - ISurfaceComposer::eDisplayIdMain));
- DisplayInfo dinfo;
- status_t status = SurfaceComposerClient::getDisplayInfo(dtoken, &dinfo);
- if (status)
- return -1;
- char value[PROPERTY_VALUE_MAX];
- property_get("persist.panel.orientation", value, "0");
- int orient = atoi(value) / 90;
- if(orient == eOrientation90 || orient == eOrientation270) {
- int temp = dinfo.h;
- dinfo.h = dinfo.w;
- dinfo.w = temp;
- }
- Rect destRect(dinfo.w, dinfo.h);
- mSession->setDisplayProjection(dtoken, orient, destRect, destRect);
- // create the native surface
- sp
control = session()->createSurface(String8("BootAnimation"), - dinfo.w, dinfo.h, PIXEL_FORMAT_RGB_565);
- SurfaceComposerClient::openGlobalTransaction();
- control->setLayer(0x40000000);
- SurfaceComposerClient::closeGlobalTransaction();
- sp
s = control->getSurface(); - // initialize opengl and egl
- const EGLint attribs[] = {
- EGL_RED_SIZE, 8,
- EGL_GREEN_SIZE, 8,
- EGL_BLUE_SIZE, 8,
- EGL_DEPTH_SIZE, 0,
- EGL_NONE
- };
- EGLint w, h, dummy;
- EGLint numConfigs;
- EGLConfig config;
- EGLSurface surface;
- EGLContext context;
- EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
- eglInitialize(display, 0, 0);
- eglChooseConfig(display, attribs, &config, 1, &numConfigs);
- surface = eglCreateWindowSurface(display, config, s.get(), NULL);
- context = eglCreateContext(display, config, NULL, NULL);
- eglQuerySurface(display, surface, EGL_WIDTH, &w);
- eglQuerySurface(display, surface, EGL_HEIGHT, &h);
- if (eglMakeCurrent(display, surface, surface, context) == EGL_FALSE)
- return NO_INIT;
- mDisplay = display;
- mContext = context;
- mSurface = surface;
- mWidth = w;
- mHeight = h;
- mFlingerSurfaceControl = control;
- mFlingerSurface = s;
- mAndroidAnimation = true;
- // If the device has encryption turned on or is in process
- // of being encrypted we show the encrypted boot animation.
- char decrypt[PROPERTY_VALUE_MAX];
- property_get("vold.decrypt", decrypt, "");
- bool encryptedAnimation = atoi(decrypt) != 0 || !strcmp("trigger_restart_min_framework", decrypt);
- if ((encryptedAnimation &&
- (access(SYSTEM_ENCRYPTED_BOOTANIMATION_FILE, R_OK) == 0) &&
- (mZip.open(SYSTEM_ENCRYPTED_BOOTANIMATION_FILE) == NO_ERROR)) ||
- ((access(USER_BOOTANIMATION_FILE, R_OK) == 0) &&
- (mZip.open(USER_BOOTANIMATION_FILE) == NO_ERROR)) ||
- ((access(SYSTEM_BOOTANIMATION_FILE, R_OK) == 0) &&
- (mZip.open(SYSTEM_BOOTANIMATION_FILE) == NO_ERROR))) {
- mAndroidAnimation = false;
- }
- return NO_ERROR;
- }
threadloop实现
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- bool BootAnimation::threadLoop()
- {
- bool r;
- if (mAndroidAnimation) {
- r = android();//显示android默认动画
- } else {
- r = movie();//显示自定义的动画
- }
- // No need to force exit anymore
- property_set(EXIT_PROP_NAME, "0");
- eglMakeCurrent(mDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
- eglDestroyContext(mDisplay, mContext);
- eglDestroySurface(mDisplay, mSurface);
- mFlingerSurface.clear();
- mFlingerSurfaceControl.clear();
- eglTerminate(mDisplay);
- IPCThreadState::self()->stopProcess();
- return r;
- }
movie()的实现
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- bool BootAnimation::movie()
- {
- //读取bootanimation.zip文件并解释
- // clear screen
- //下面是循环显示
- for (int i=0 ; i
- const Animation::Part& part(animation.parts[i]);
- const size_t fcount = part.frames.size();
- glBindTexture(GL_TEXTURE_2D, 0);
- for (int r=0 ; !part.count || r
- // Exit any non playuntil complete parts immediately
- if(exitPending() && !part.playUntilComplete)
- break;
- for (int j=0 ; j
- const Animation::Frame& frame(part.frames[j]);
- nsecs_t lastFrame = systemTime();
- if (r > 0) {
- glBindTexture(GL_TEXTURE_2D, frame.tid);
- } else {
- if (part.count != 1) {
- glGenTextures(1, &frame.tid);
- glBindTexture(GL_TEXTURE_2D, frame.tid);
- glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
- glTexParameterx(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
- }
- initTexture(
- frame.map->getDataPtr(),
- frame.map->getDataLength());
- }
- if (!clearReg.isEmpty()) {
- Region::const_iterator head(clearReg.begin());
- Region::const_iterator tail(clearReg.end());
- glEnable(GL_SCISSOR_TEST);
- while (head != tail) {
- const Rect& r(*head++);
- glScissor(r.left, mHeight - r.bottom,
- r.width(), r.height());
- glClear(GL_COLOR_BUFFER_BIT);
- }
- glDisable(GL_SCISSOR_TEST);
- }
- glDrawTexiOES(xc, yc, 0, animation.width, animation.height);
- eglSwapBuffers(mDisplay, mSurface);
- nsecs_t now = systemTime();
- nsecs_t delay = frameDuration - (now - lastFrame);
- //ALOGD("%lld, %lld", ns2ms(now - lastFrame), ns2ms(delay));
- lastFrame = now;
- if (delay > 0) {
- struct timespec spec;
- spec.tv_sec = (now + delay) / 1000000000;
- spec.tv_nsec = (now + delay) % 1000000000;
- int err;
- do {
- err = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &spec, NULL);
- } while (err<0 && errno == EINTR);
- }
- checkExit();//检测是否退出动画
- }
- usleep(part.pause * ns2us(frameDuration));
- // For infinite parts, we've now played them at least once, so perhaps exit
- if(exitPending() && !part.count)
- break;
- }
- // free the textures for this part
- if (part.count != 1) {
- for (int j=0 ; j
- const Animation::Frame& frame(part.frames[j]);
- glDeleteTextures(1, &frame.tid);
- }
- }
- }
- return false;
- }
那么到movie为止,动画是在播放了,而且还在循环检测是否退出,即checkExit()
checkExit()的实现
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- void BootAnimation::checkExit() {
- // Allow surface flinger to gracefully request shutdown
- char value[PROPERTY_VALUE_MAX];
- property_get(EXIT_PROP_NAME, value, "0");//属性为1,说明要退出了
- int exitnow = atoi(value);
- if (exitnow) {
- requestExit();
- }
- }
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- property_get(EXIT_PROP_NAME, value, "0");检测这个属性,=1就退出动画
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- #define EXIT_PROP_NAME "service.bootanim.exit"
这个属性就是上面讲到的,等到launcher跑起来后就会置1
那动画是什么时候退出的?
当launcher应用程序主线程跑起来后,如果主线程处于空闲,就会向ActivityManagerService发送一个activityIdle的消息。
应用程序主线程是ActivityThread.java来描述的,activityIdle是这个类来实现的
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- private class Idler implements MessageQueue.IdleHandler {
- ...
- IActivityManager am = ActivityManagerNative.getDefault();
- ...
- try {
- am.activityIdle(a.token, a.createdConfig, stopProfiling);
- a.createdConfig = null;
- } catch (RemoteException ex) {
- // Ignore
- }
- ....
- }
上面的ActivityManagerNavtive.getDefault()得到am
来到frameworks/base/core/java/android/app/ActivityManagerNative.java
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- static public IActivityManager getDefault() {
- return gDefault.get();//getDefault的实现
- }
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- private static final Singleton
gDefault = new Singleton () { - protected IActivityManager create() {
- IBinder b = ServiceManager.getService("activity");
- if (false) {
- Log.v("ActivityManager", "default service binder = " + b);
- }
- IActivityManager am = asInterface(b);
- if (false) {
- Log.v("ActivityManager", "default service = " + am);
- }
- return am;
- }
- };
gDefault实际上是IActivityManager,往下看
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- class ActivityManagerProxy implements IActivityManager
- {
ActivityManagerProxy实现了IActivityManager
那么am.activityIdle()就是ActivityManagerProxy里的函数,如下
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- public void activityIdle(IBinder token, Configuration config, boolean stopProfiling)
- throws RemoteException
- {
- ...
- mRemote.transact(ACTIVITY_IDLE_TRANSACTION, data, reply, IBinder.FLAG_ONEWAY);//发送ACTIVITY_IDLE_TRANSACTION
- ....
- }
发送了ACTIVITY_IDLE_TRANSACTION的进程间通信,这个消息被ActivityManagerNative接收处理了。
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- case ACTIVITY_IDLE_TRANSACTION: {//收到消息
- data.enforceInterface(IActivityManager.descriptor);
- IBinder token = data.readStrongBinder();
- Configuration config = null;
- if (data.readInt() != 0) {
- config = Configuration.CREATOR.createFromParcel(data);
- }
- boolean stopProfiling = data.readInt() != 0;
- if (token != null) {
- activityIdle(token, config, stopProfiling);//这个函数在ActivityManagerService被重写
- }
- reply.writeNoException();
- return true;
- }
收到消息后就调用了activityIdle函数,这个函数被ActivityManagerService重写了,如下
frameworks/base/services/java/com/android/server/am/ActivityManagerService.java
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- @Override
- public final void activityIdle(IBinder token, Configuration config, boolean stopProfiling) {
- final long origId = Binder.clearCallingIdentity();
- synchronized (this) {
- ActivityStack stack = ActivityRecord.getStackLocked(token);
- if (stack != null) {
- ActivityRecord r =
- mStackSupervisor.activityIdleInternalLocked(token, false, config);
- if (stopProfiling) {
- if ((mProfileProc == r.app) && (mProfileFd != null)) {
- try {
- mProfileFd.close();
- } catch (IOException e) {
- }
- clearProfilerLocked();
- }
- }
- }
- }
- Binder.restoreCallingIdentity(origId);
- }
调用activityIdleInternalLocked函数,在下面实现
frameworks/base/services/java/com/android/server/am/ActivityStackSupervisor.java
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- final ActivityRecord activityIdleInternalLocked(final IBinder token, boolean fromTimeout,
- Configuration config) {
- ....
- if (enableScreen) {
- mService.enableScreenAfterBoot();//调ActivityManagerService类的enableScreenAfterBoot()函数
- }
- ....
- if (activityRemoved) {
- resumeTopActivitiesLocked();
- }
- return r;
- }
来到frameworks/base/services/java/com/android/server/am/ActivityManagerService.java
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- void enableScreenAfterBoot() {
- EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_ENABLE_SCREEN,
- SystemClock.uptimeMillis());
- mWindowManager.enableScreenAfterBoot();//调WindowManagerService类里的enableScreenAfterBoot()函数
- synchronized (this) {
- updateEventDispatchingLocked();
- }
- }
来到frameworks/base/services/java/com/android/server/wm/WindowManagerService.java
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- public void enableScreenAfterBoot() {
- ....
- performEnableScreen();
- }
performEnableScreen()实现
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- public void performEnableScreen() {
- ..
- surfaceFlinger.transact(IBinder.FIRST_CALL_TRANSACTION, // BOOT_FINISHED
- data, null, 0);
- ....
- }
发送了FIRST_CALL_TRANSACTION的请求
因为从下面知道FIRST_CALL_TRANSACTION = BOOT_FINISHED
所以BnSurfaceComposer收到消息
frameworks/native/include/gui/ISurfaceComposer.h
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- class BnSurfaceComposer: public BnInterface
{ - public:
- enum {
- // Note: BOOT_FINISHED must remain this value, it is called from
- // Java by ActivityManagerService.
- BOOT_FINISHED = IBinder::FIRST_CALL_TRANSACTION,
- ...
- };
- virtual status_t onTransact(uint32_t code, const Parcel& data,
- Parcel* reply, uint32_t flags = 0);
- };
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frameworks/native/libs/gui/ISurfaceComposer.cpp
status_t BnSurfaceComposer::onTransact(
- uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
- {
- switch(code) {
- ....
- case BOOT_FINISHED: {
- CHECK_INTERFACE(ISurfaceComposer, data, reply);
- bootFinished();//调用 bootFinished()
- return NO_ERROR;
- }
- ....
- }
- // should be unreachable
- return NO_ERROR;
- }
bootFinished()函数BpSurfaceComposer里实现,但发现没有,他又发了一个BOOT_FINISHED,死循环了,其实没有。bootFinished()被SurfaceFlinger类重写了
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- class BpSurfaceComposer : public BpInterface
- {
- virtual void bootFinished()
- {
- Parcel data, reply;
- data.writeInterfaceToken(ISurfaceComposer::getInterfaceDescriptor());
- remote()->transact(BnSurfaceComposer::BOOT_FINISHED, data, &reply);
- }
重写
frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp
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- void SurfaceFlinger::bootFinished()
- {
- ...
- property_set("service.bootanim.exit", "1");
- }
把service.bootanim.exit写成1,然后bootanimation进程的checkExit()检测到就退出进程,停止播放。