- per-thread的单例模式
//单例子模式，per-thread的单例模式
IPCThreadState* IPCThreadState::self() //IPCThreadState.cpp
{
if (gHaveTLS.load(std::memory_order_acquire)) {
restart:
const pthread_key_t k = gTLS;
IPCThreadState* st = (IPCThreadState*)pthread_getspecific(k);
if (st) return st;
return new IPCThreadState;
}
// Racey, heuristic test for simultaneous shutdown.
if (gShutdown.load(std::memory_order_relaxed)) {
ALOGW("Calling IPCThreadState::self() during shutdown is dangerous, expect a crash.\n");
return nullptr;
}
pthread_mutex_lock(&gTLSMutex);
if (!gHaveTLS.load(std::memory_order_relaxed)) {
int key_create_value = pthread_key_create(&gTLS, threadDestructor);
if (key_create_value != 0) {
pthread_mutex_unlock(&gTLSMutex);
ALOGW("IPCThreadState::self() unable to create TLS key, expect a crash: %s\n",
strerror(key_create_value));
return nullptr;
}
gHaveTLS.store(true, std::memory_order_release);
}
pthread_mutex_unlock(&gTLSMutex);
goto restart;
}
Original: https://www.cnblogs.com/hellokitty2/p/16463356.html
Author: Hello-World3
Title: C++经典案例
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