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Commit 61a25b24 authored by Jeff Brown's avatar Jeff Brown
Browse files

Looper: use pthread_once for TLS key initialization. 

Also fix a Valgrind complaint by zeroing out the entire epoll event
struct since otherwise the data field union would be partly
uninitialized (but not in a harmful way).

Change-Id: I2091ce517e87fcad7c9caf90e2c5e4854a7ca465
parent efed55f5

include/utils/Looper.h

+1 −0
Original line number Diff line number Diff line
@@ -205,6 +205,7 @@ private: 


    int pollInner(int timeoutMillis);



    static void initTLSKey();

    static void threadDestructor(void *st);

};

libs/utils/Looper.cpp

+14 −15
Original line number Diff line number Diff line
@@ -24,16 +24,15 @@ 


namespace android {



static pthread_mutex_t gTLSMutex = PTHREAD_MUTEX_INITIALIZER;

static bool gHaveTLS = false;

static pthread_key_t gTLS = 0;



// Hint for number of file descriptors to be associated with the epoll instance.

static const int EPOLL_SIZE_HINT = 8;



// Maximum number of file descriptors for which to retrieve poll events each iteration.

static const int EPOLL_MAX_EVENTS = 16;



static pthread_once_t gTLSOnce = PTHREAD_ONCE_INIT;

static pthread_key_t gTLSKey = 0;



Looper::Looper(bool allowNonCallbacks) :

        mAllowNonCallbacks(allowNonCallbacks),

        mResponseIndex(0) {
@@ -56,6 +55,7 @@ Looper::Looper(bool allowNonCallbacks) : 
            errno);



    struct epoll_event eventItem;

    memset(& eventItem, 0, sizeof(epoll_event)); // zero out unused members of data field union

    eventItem.events = EPOLLIN;

    eventItem.data.fd = mWakeReadPipeFd;

    result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mWakeReadPipeFd, & eventItem);
@@ -69,6 +69,11 @@ Looper::~Looper() { 
    close(mEpollFd);

}



void Looper::initTLSKey() {

    int result = pthread_key_create(& gTLSKey, threadDestructor);

    LOG_ALWAYS_FATAL_IF(result != 0, "Could not allocate TLS key.");

}



void Looper::threadDestructor(void *st) {

    Looper* const self = static_cast<Looper*>(st);

    if (self != NULL) {
@@ -83,7 +88,7 @@ void Looper::setForThread(const sp<Looper>& looper) { 
        looper->incStrong((void*)threadDestructor);

    }



    pthread_setspecific(gTLS, looper.get());

    pthread_setspecific(gTLSKey, looper.get());



    if (old != NULL) {

        old->decStrong((void*)threadDestructor);
@@ -91,17 +96,10 @@ void Looper::setForThread(const sp<Looper>& looper) { 
}



sp<Looper> Looper::getForThread() {

    if (!gHaveTLS) {

        pthread_mutex_lock(&gTLSMutex);

        if (pthread_key_create(&gTLS, threadDestructor) != 0) {

            pthread_mutex_unlock(&gTLSMutex);

            return NULL;

        }

        gHaveTLS = true;

        pthread_mutex_unlock(&gTLSMutex);

    }

    int result = pthread_once(& gTLSOnce, initTLSKey);

    LOG_ALWAYS_FATAL_IF(result != 0, "pthread_once failed");



    return (Looper*)pthread_getspecific(gTLS);

    return (Looper*)pthread_getspecific(gTLSKey);

}



sp<Looper> Looper::prepare(int opts) {
@@ -331,6 +329,7 @@ int Looper::addFd(int fd, int ident, int events, ALooper_callbackFunc callback, 
        request.data = data;



        struct epoll_event eventItem;

        memset(& eventItem, 0, sizeof(epoll_event)); // zero out unused members of data field union

        eventItem.events = epollEvents;

        eventItem.data.fd = fd;