threads.c

Android 一些工具

/* libs/cutils/threads.c
**
** Copyright (C) 2007, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License"); 
** you may not use this file except in compliance with the License. 
** You may obtain a copy of the License at 
**
**     http://www.apache.org/licenses/LICENSE-2.0 
**
** Unless required by applicable law or agreed to in writing, software 
** distributed under the License is distributed on an "AS IS" BASIS, 
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
** See the License for the specific language governing permissions and 
** limitations under the License.
*/
#include <cutils/threads.h>

#ifdef HAVE_PTHREADS
void*  thread_store_get( thread_store_t*  store )
{
    const pthread_key_t  k = store->tls;

    if (!store->has_tls)
        return NULL;

    return pthread_getspecific( store->tls );
}
    
extern void   thread_store_set( thread_store_t*          store, 
                                void*                    value,
                                thread_store_destruct_t  destroy)
{
    pthread_mutex_lock( &store->lock );
    if (!store->has_tls) {
        if (pthread_key_create( &store->tls, destroy) != 0) {
            pthread_mutex_unlock(&store->lock);
            return;
        }
        store->has_tls = 1;
    }
    pthread_mutex_unlock( &store->lock );

    pthread_setspecific( store->tls, value );
}

#endif

#ifdef HAVE_WIN32_THREADS
void*  thread_store_get( thread_store_t*  store )
{
    if (!store->has_tls)
        return NULL;
    
    return (void*) TlsGetValue( store->tls );
}

void   thread_store_set( thread_store_t*          store,
                         void*                    value,
                         thread_store_destruct_t  destroy )
{
    /* XXX: can't use destructor on thread exit */
    if (!store->lock_init) {
        store->lock_init = -1;
        InitializeCriticalSection( &store->lock );
        store->lock_init = -2;
    } else while (store->lock_init != -2) {
        Sleep(10); /* 10ms */
    }
        
    EnterCriticalSection( &store->lock );
    if (!store->has_tls) {
        store->tls = TlsAlloc();
        if (store->tls == TLS_OUT_OF_INDEXES) {
            LeaveCriticalSection( &store->lock );
            return;
        }
        store->has_tls = 1;
    }
    LeaveCriticalSection( &store->lock );
    
    TlsSetValue( store->tls, value );
}
#endif