ThreadPool.h revision 262059f71a68edc5e510427c63f5f1623d3672a8 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/** \file ThreadPool.h ThreadPool interface */
18
19/** \brief Closure represents a deferred computation */
20
21typedef struct {
22    void (*mHandler)(void *, int);
23    void *mContext;
24    int mParameter;
25} Closure;
26
27/** \brief ThreadPool manages a pool of worker threads that execute Closures */
28
29typedef struct {
30    unsigned mInitialized; ///< Indicates which of the following 3 fields are initialized
31    pthread_mutex_t mMutex;
32    pthread_cond_t mCondNotFull;    ///< Signalled when a client thread could be unblocked
33    pthread_cond_t mCondNotEmpty;   ///< Signalled when a worker thread could be unblocked
34    SLboolean mShutdown;   ///< Whether shutdown of thread pool has been requested
35    unsigned mWaitingNotFull;   ///< Number of client threads waiting to enqueue
36    unsigned mWaitingNotEmpty;  ///< Number of worker threads waiting to dequeue
37    unsigned mMaxClosures;  ///< Number of slots in circular buffer for closures, not counting spare
38    unsigned mMaxThreads;   ///< Number of worker threads
39    Closure **mClosureArray;    ///< The circular buffer of closures
40    Closure **mClosureFront, **mClosureRear;
41    /// Saves a malloc in the typical case
42#define CLOSURE_TYPICAL 15
43    Closure *mClosureTypical[CLOSURE_TYPICAL+1];
44    pthread_t *mThreadArray;    ///< The worker threads
45#ifdef ANDROID
46#define THREAD_TYPICAL 0
47#else
48#define THREAD_TYPICAL 4
49#endif
50    pthread_t mThreadTypical[THREAD_TYPICAL];
51} ThreadPool;
52
53extern SLresult ThreadPool_init(ThreadPool *tp, unsigned maxClosures, unsigned maxThreads);
54extern void ThreadPool_deinit(ThreadPool *tp);
55extern SLresult ThreadPool_add(ThreadPool *tp, void (*handler)(void *, int), void *context,
56    int parameter);
57extern Closure *ThreadPool_remove(ThreadPool *tp);
58