IPCThreadState.cpp

源码位置：
frameworks/native/libs/binder/IPCThreadState.cpp

https://blog.csdn.net/CrazyMo_/article/details/129143626

方法

实例化

每个线程都有一个IPCThreadState

• 构造函数

  802 IPCThreadState::IPCThreadState()
  803     : mProcess(ProcessState::self()),
  804       mWorkSource(kUnsetWorkSource),
  805       mPropagateWorkSource(false),
  806       mStrictModePolicy(0),
  807       mLastTransactionBinderFlags(0),
  808       mCallRestriction(mProcess->mCallRestriction)
  809 {
  810     pthread_setspecific(gTLS, this);
  811     clearCaller();
  812     mIn.setDataCapacity(256);
  813     mOut.setDataCapacity(256);
  814     mIPCThreadStateBase = IPCThreadStateBase::self();
  815 }

  mProcess(ProcessState::self()) 将当前线程的进程指针记录起来
  pthread_setspecific(gTLS, this); 将IPCThreadState实例与线程绑定

• self

  281 static bool gHaveTLS = false;
  282 static pthread_key_t gTLS = 0;
  
  286 IPCThreadState* IPCThreadState::self()
  287 {
  288     if (gHaveTLS) {
  289 restart:
  290         const pthread_key_t k = gTLS;
  291         IPCThreadState* st = (IPCThreadState*)pthread_getspecific(k);
  292         if (st) return st;
  293         return new IPCThreadState;
  294     }
  295 
  296     if (gShutdown) {
  297         ALOGW("Calling IPCThreadState::self() during shutdown is dangerous, expect a crash.\n");
  298         return nullptr;
  299     }
  300 
  301     pthread_mutex_lock(&gTLSMutex);
  302     if (!gHaveTLS) {
  303         int key_create_value = pthread_key_create(&gTLS, threadDestructor);
  304         if (key_create_value != 0) {
  305             pthread_mutex_unlock(&gTLSMutex);
  306             ALOGW("IPCThreadState::self() unable to create TLS key, expect a crash: %s\n",
  307                     strerror(key_create_value));
  308             return nullptr;
  309         }
  310         gHaveTLS = true;
  311     }
  312     pthread_mutex_unlock(&gTLSMutex);
  313     goto restart;
  314 }

talkWithDriver（与binder驱动交互的核心方法）

ioctl(mProcess->mDriverFD, BINDER_WRITE_READ, &bwr)

各种xxHandle()方法

• incWeakHandle

 737 void IPCThreadState::incWeakHandle(int32_t handle, BpBinder *proxy)
 738 {
 739     LOG_REMOTEREFS("IPCThreadState::incWeakHandle(%d)\n", handle);
 740     mOut.writeInt32(BC_INCREFS);
 741     mOut.writeInt32(handle);
 742     // Create a temp reference until the driver has handled this command.
 743     proxy->getWeakRefs()->incWeak(mProcess.get());
 744     mPostWriteWeakDerefs.push(proxy->getWeakRefs());
 745 }