ThreadPool.h revision cf3a6383a9bc9a94ca5b424ea97313293ee0dcb0 
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/** Kind of closure */
20
21typedef enum {
22    CLOSURE_KIND_PPI,   // void *, void *, int
23    CLOSURE_KIND_PPII   // void *, void *, int, int
24} ClosureKind;
25
26/** Closure handlers */
27
28typedef void (*ClosureHandler_ppi)(void *context1, void *context2, int parameter1);
29typedef void (*ClosureHandler_ppii)(void *context1, void *context2, int parameter1, int parameter2);
30
31/** \brief Closure represents a deferred computation */
32
33typedef struct {
34    union {
35        ClosureHandler_ppi mHandler_ppi;
36        ClosureHandler_ppii mHandler_ppii;
37    } mHandler;
38    ClosureKind mKind;
39    void *mContext1;
40    void *mContext2;
41    int mParameter1;
42    int mParameter2;
43} Closure;
44
45/** \brief ThreadPool manages a pool of worker threads that execute Closures */
46
47typedef struct {
48    unsigned mInitialized; ///< Indicates which of the following 3 fields are initialized
49    pthread_mutex_t mMutex;
50    pthread_cond_t mCondNotFull;    ///< Signalled when a client thread could be unblocked
51    pthread_cond_t mCondNotEmpty;   ///< Signalled when a worker thread could be unblocked
52    SLboolean mShutdown;   ///< Whether shutdown of thread pool has been requested
53    unsigned mWaitingNotFull;   ///< Number of client threads waiting to enqueue
54    unsigned mWaitingNotEmpty;  ///< Number of worker threads waiting to dequeue
55    unsigned mMaxClosures;  ///< Number of slots in circular buffer for closures, not counting spare
56    unsigned mMaxThreads;   ///< Number of worker threads
57    Closure **mClosureArray;    ///< The circular buffer of closures
58    Closure **mClosureFront, **mClosureRear;
59    /// Saves a malloc in the typical case
60#define CLOSURE_TYPICAL 15
61    Closure *mClosureTypical[CLOSURE_TYPICAL+1];
62    pthread_t *mThreadArray;    ///< The worker threads
63#ifdef ANDROID
64#define THREAD_TYPICAL 2
65#else
66#define THREAD_TYPICAL 4
67#endif
68    pthread_t mThreadTypical[THREAD_TYPICAL];
69} ThreadPool;
70
71extern SLresult ThreadPool_init(ThreadPool *tp, unsigned maxClosures, unsigned maxThreads);
72extern void ThreadPool_deinit(ThreadPool *tp);
73extern SLresult ThreadPool_add(ThreadPool *tp, ClosureKind kind,
74    void (*handler)(void *, void *, int, int), void *context1,
75    void *context2, int parameter1, int parameter2);
76extern Closure *ThreadPool_remove(ThreadPool *tp);
77extern SLresult ThreadPool_add_ppi(ThreadPool *tp, ClosureHandler_ppi handler,
78    void *context1, void *context2, int parameter1);
79extern SLresult ThreadPool_add_ppii(ThreadPool *tp, ClosureHandler_ppii handler,
80    void *context1, void *context2, int parameter1, int parameter2);
81