android8.1开机动画停止分析

最新推荐文章于 2024-06-07 15:54:02 发布

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最新推荐文章于 2024-06-07 15:54:02 发布

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分类专栏： androidframework 文章标签： android

本文链接：https://blog.youkuaiyun.com/we1less/article/details/116504388

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本文详细分析了Android系统中开机动画的关闭流程，从WindowManagerService的performEnableScreen()方法开始，通过设置'service.bootanim.exit'属性为1来请求结束开机动画。这一过程涉及到SurfaceFlinger服务的交互，最终由SurfaceFlinger设置该属性来完成动画的停止。整个过程涉及跨进程通信和Binder调用。

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文章初始给大家推荐一篇文章https://blog.youkuaiyun.com/xlnaan/article/details/80904309#commentBox

上篇文章已经分析到开机动画的两种播放形式了https://blog.youkuaiyun.com/we1less/article/details/116464874

首先以android()方式播放

android() AOSP/frameworks/base/cmds/bootanimation/BootAnimation.cpp

bool BootAnimation::android()
{
   {
        ...
        checkExit();
    } while (!exitPending());
    ...
    return false;
}

这里可以看到在开机动画播放的循环当中以checkExit()判断终止循环播放

void BootAnimation::checkExit() {
    // Allow surface flinger to gracefully request shutdown
    char value[PROPERTY_VALUE_MAX];
    property_get(EXIT_PROP_NAME, value, "0");
    int exitnow = atoi(value);
    if (exitnow) {
        requestExit();
        mCallbacks->shutdown();
    }
}

关于这个requestExit() 和exitPending()可以参考https://blog.youkuaiyun.com/llping2011/article/details/9706599 大致意思就是调用requestExit() ExitexitPending()就会返回true

可以在这看出退出循环的标志就是 EXIT_PROP_NAME 的值默认是0

static const char EXIT_PROP_NAME[] = "service.bootanim.exit";

可以查询一下这个属性到底在哪做过设置

godv@godv-OptiPlex-7070:~/godv/AOSP/android-8.1.0_r1/frameworks$ grep "service.bootanim.exit" ./ -rn
./native/services/surfaceflinger/SurfaceFlinger_hwc1.cpp:341:    property_set("service.bootanim.exit", "1");
./native/services/surfaceflinger/StartPropertySetThread.cpp:33:    property_set("service.bootanim.exit", "0");
./native/services/surfaceflinger/SurfaceFlinger.cpp:388:    property_set("service.bootanim.exit", "1");
./base/cmds/bootanimation/BootAnimation.cpp:93:static const char EXIT_PROP_NAME[] = "service.bootanim.exit";
./base/cmds/bootanimation/FORMAT.md:77:the system property `service.bootanim.exit` to a nonzero string.)
./base/services/core/java/com/android/server/wm/WindowManagerService.java:3509:                SystemProperties.set("service.bootanim.exit", "1");

可以看出 service.bootanim.exit 这个属性在 SurfaceFlinger.cpp:388 和 WindowManagerService.java:3509 出现过

首先看WindowManagerService出现的位置

WindowManagerService.java AOSP/frameworks/base/services/core/java/com/android/server/wm

    private void performEnableScreen() {
        synchronized(mWindowMap) {
            ...
            if (!mBootAnimationStopped) {
                Trace.asyncTraceBegin(TRACE_TAG_WINDOW_MANAGER, "Stop bootanim", 0);
                // stop boot animation
                // formerly we would just kill the process, but we now ask it to exit so it
                // can choose where to stop the animation.
                SystemProperties.set("service.bootanim.exit", "1");
                mBootAnimationStopped = true;
            }
            ...
}

在不明确当前函数performEnableScreen()如何调用可以使用打印堆栈来实现查看调用链具体可以参考https://blog.youkuaiyun.com/we1less/article/details/115792043

03-09 00:53:27.569  1712  1712 I lsm2    : Scheduling idle handler for ActivityRecord{5c8f360 token=android.os.BinderProxy@6d26d5c {com.android.settings/com.android.settings.FallbackHome}}
//1、进入idle
03-09 00:53:27.687  1712  1712 I lsm2    :  activityIdle a.activity ComponentInfo{com.android.settings/com.android.settings.FallbackHome}
//2、跨进程调用到AMS中，执行了postFinishBooting
03-09 00:53:27.941  1529  1584 D lsm2    : postFinishBooting finishBooting true enableScreen true
03-09 00:53:27.941  1529  1584 D lsm2    : java.lang.Exception
03-09 00:53:27.941  1529  1584 D lsm2    : 	at com.android.server.am.ActivityManagerService.postFinishBooting(ActivityManagerService.java:7244)
03-09 00:53:27.941  1529  1584 D lsm2    : 	at com.android.server.am.ActivityStackSupervisor.checkFinishBootingLocked(ActivityStackSupervisor.java:1874)
03-09 00:53:27.941  1529  1584 D lsm2    : 	at com.android.server.am.ActivityStackSupervisor.activityIdleInternalLocked(ActivityStackSupervisor.java:1916)
03-09 00:53:27.941  1529  1584 D lsm2    : 	at com.android.server.am.ActivityManagerService.activityIdle(ActivityManagerService.java:7231)
03-09 00:53:27.941  1529  1584 D lsm2    : 	at android.app.IActivityManager$Stub.onTransact(IActivityManager.java:309)
03-09 00:53:27.941  1529  1584 D lsm2    : 	at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:2919)
03-09 00:53:27.941  1529  1584 D lsm2    : 	at android.os.Binder.execTransact(Binder.java:697)
//3、调用到WMS中的performEnableScreen
03-09 00:52:44.223  1529  1552 D lsm2    :  WindowManagerService performEnableScreen Stop bootanim
03-09 00:52:44.223  1529  1552 D lsm2    : java.lang.Exception
03-09 00:52:44.223  1529  1552 D lsm2    : 	at com.android.server.wm.WindowManagerService.performEnableScreen(WindowManagerService.java:3511)
03-09 00:52:44.223  1529  1552 D lsm2    : 	at com.android.server.wm.WindowManagerService.-wrap6(Unknown Source:0)
03-09 00:52:44.223  1529  1552 D lsm2    : 	at com.android.server.wm.WindowManagerService$H.handleMessage(WindowManagerService.java:5065)
03-09 00:52:44.223  1529  1552 D lsm2    : 	at android.os.Handler.dispatchMessage(Handler.java:106)
03-09 00:52:44.223  1529  1552 D lsm2    : 	at android.os.Looper.loop(Looper.java:164)
03-09 00:52:44.223  1529  1552 D lsm2    : 	at android.os.HandlerThread.run(HandlerThread.java:65)
03-09 00:52:44.223  1529  1552 D lsm2    : 	at com.android.server.ServiceThread.run(ServiceThread.java:46)
//4、跨进程调用到SurfaceFlinger
03-09 00:52:44.310  1529  1552 D lsm2    :  WindowManagerService performEnableScreen  surfaceFlinger.transact(IBinder.FIRST_CALL_TRANSACTION 
//5、SurfaceFlinger执行prop的设置
03-09 00:52:44.311  1368  1594 I SurfaceFlinger: lsm2 SurfaceFlinger service.bootanim.exit 1 
03-09 00:52:45.573  2014  2014 I lsm2    : Scheduling idle handler for ActivityRecord{f5df6ba token=android.os.BinderProxy@80709eb {com.android.launcher/com.android.launcher2.Launcher}}

可以从上述log中看出当FallbackHome进入idle的状态后会跨进程通信调用到AMS中再跨进程通信调用到WMS中调用performEnableScreen()方法这个方法设置属性控制开机动画结束

/native/services/surfaceflinger/SurfaceFlinger.cpp:388:    property_set("service.bootanim.exit", "1");

第二也可以在SurfaceFlinger 388行发现设置开机动画结束属性

bootFinished() AOSP/frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp

void SurfaceFlinger::bootFinished()
{
    ...
    // stop boot animation
    // formerly we would just kill the process, but we now ask it to exit so it
    // can choose where to stop the animation.
    property_set("service.bootanim.exit", "1");
    ...
}

利用查询bootFinished()的调用过程

godv@godv-OptiPlex-7070:~/godv/AOSP/android-8.1.0_r1/frameworks$ grep "bootFinished()" ./ -rn
./native/libs/gui/ISurfaceComposer.cpp:96:    virtual void bootFinished()
./native/libs/gui/ISurfaceComposer.cpp:537:            bootFinished();
./native/libs/gui/include/gui/ISurfaceComposer.h:123:    virtual void bootFinished() = 0;
./native/libs/gui/tests/Surface_test.cpp:479:    void bootFinished() override {}
./native/services/surfaceflinger/SurfaceFlinger_hwc1.cpp:321:void SurfaceFlinger::bootFinished()
./native/services/surfaceflinger/SurfaceFlinger.h:287:    virtual void bootFinished();
./native/services/surfaceflinger/SurfaceFlinger.cpp:365:void SurfaceFlinger::bootFinished()

发现是在 ISurfaceComposer.cpp 中调用的

status_t BnSurfaceComposer::onTransact AOSP/android-8.1.0_r1/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();
            return NO_ERROR;
        }
        ...
    }
}

同样的搜索BOOT_FINISHED

godv@godv-OptiPlex-7070:~/godv/AOSP/android-8.1.0_r1/frameworks$ grep "BOOT_FINISHED" ./ -rn
./native/libs/gui/ISurfaceComposer.cpp:100:        remote()->transact(BnSurfaceComposer::BOOT_FINISHED, data, &reply);
./native/libs/gui/ISurfaceComposer.cpp:535:        case BOOT_FINISHED: {
./native/libs/gui/include/gui/ISurfaceComposer.h:205:        // Note: BOOT_FINISHED must remain this value, it is called from
./native/libs/gui/include/gui/ISurfaceComposer.h:207:        BOOT_FINISHED = IBinder::FIRST_CALL_TRANSACTION,
./native/services/surfaceflinger/SurfaceFlinger_hwc1.cpp:3384:        case BOOT_FINISHED:
./native/services/surfaceflinger/SurfaceFlinger.cpp:3889:        case BOOT_FINISHED:
./base/services/core/java/com/android/server/wm/WindowManagerService.java:3525:                    surfaceFlinger.transact(IBinder.FIRST_CALL_TRANSACTION, // BOOT_FINISHED

./native/libs/gui/include/gui/ISurfaceComposer.h:207:        BOOT_FINISHED = IBinder::FIRST_CALL_TRANSACTION,

继续搜索 IBinder::FIRST_CALL_TRANSACTION

godv@godv-OptiPlex-7070:~/godv/AOSP/android-8.1.0_r1/frameworks$ grep "FIRST_CALL_TRANSACTION," ./ -rn | grep "surface"
./base/services/core/java/com/android/server/wm/WindowManagerService.java:3525:                    surfaceFlinger.transact(IBinder.FIRST_CALL_TRANSACTION, // BOOT_FINISHED

发现同样的又在WMS中调用的看WMS中的代码

WindowManagerService.java AOSP/frameworks/base/services/core/java/com/android/server/wm

    private void performEnableScreen() {
        synchronized(mWindowMap) {
            ...
            if (!mBootAnimationStopped) {
                Trace.asyncTraceBegin(TRACE_TAG_WINDOW_MANAGER, "Stop bootanim", 0);
                // stop boot animation
                // formerly we would just kill the process, but we now ask it to exit so it
                // can choose where to stop the animation.
                SystemProperties.set("service.bootanim.exit", "1");
                mBootAnimationStopped = true;
            }
            ...
            try {
                IBinder surfaceFlinger = ServiceManager.getService("SurfaceFlinger");
                if (surfaceFlinger != null) {
                    Slog.i(TAG_WM, "******* TELLING SURFACE FLINGER WE ARE BOOTED!");
                    Parcel data = Parcel.obtain();
                    data.writeInterfaceToken("android.ui.ISurfaceComposer");
                    surfaceFlinger.transact(IBinder.FIRST_CALL_TRANSACTION, // BOOT_FINISHED
                            data, null, 0);
                    data.recycle();
                }
            } catch (RemoteException ex) {
                Slog.e(TAG_WM, "Boot completed: SurfaceFlinger is dead!");
            }

}

此时发现两个不同设置开机动画属性停止动画的起始位置居然是同一个函数而且还是先后顺序执行的

这样就调到了surfaceFlinger.transact

SurfaceFlinger::onTransact AOSP/android-8.1.0_r1/frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp

status_t SurfaceFlinger::onTransact(
    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
{
    ...
    status_t err = BnSurfaceComposer::onTransact(code, data, reply, flags);
    ...
}

由此调用BnSurfaceComposer::onTransact此时一个闭环已经形成了