Android 4.4KitKat AudioFlinger 流程分析

AudioFlinger(AF)是一个服务,具体的代码在av\media\mediaserver\Main_mediaserver.cpp中:

int main(int argc, char** argv)
{
    signal(SIGPIPE, SIG_IGN);
    char value[PROPERTY_VALUE_MAX];
    bool doLog = (property_get("ro.test_harness", value, "0") > 0) && (atoi(value) == 1);
    pid_t childPid;
    // FIXME The advantage of making the process containing media.log service the parent process of
    // the process that contains all the other real services, is that it allows us to collect more
    // detailed information such as signal numbers, stop and continue, resource usage, etc.
    // But it is also more complex.  Consider replacing this by independent processes, and using
    // binder on death notification instead.
    if (doLog && (childPid = fork()) != 0) {
        // media.log service
        //prctl(PR_SET_NAME, (unsigned long) "media.log", 0, 0, 0);
        // unfortunately ps ignores PR_SET_NAME for the main thread, so use this ugly hack
        strcpy(argv[0], "media.log");
        sp<ProcessState> proc(ProcessState::self());
        MediaLogService::instantiate();
        ProcessState::self()->startThreadPool();
        ……
        sp<ProcessState> proc(ProcessState::self());
        sp<IServiceManager> sm = defaultServiceManager();
        ALOGI("ServiceManager: %p", sm.get());
        AudioFlinger::instantiate();
        MediaPlayerService::instantiate();
        CameraService::instantiate();
        AudioPolicyService::instantiate();
        registerExtensions();
        ProcessState::self()->startThreadPool();
        IPCThreadState::self()->joinThreadPool();
    }
}

郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。