1// Copyright 2013 Google Inc. All Rights Reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the COPYING file in the root of the source
5// tree. An additional intellectual property rights grant can be found
6// in the file PATENTS. All contributing project authors may
7// be found in the AUTHORS file in the root of the source tree.
8// -----------------------------------------------------------------------------
9//
10// Multi-threaded worker
11//
12// Original source:
13//  http://git.chromium.org/webm/libwebp.git
14//  100644 blob eff8f2a8c20095aade3c292b0e9292dac6cb3587  src/utils/thread.c
15
16
17#include <assert.h>
18#include <string.h>   // for memset()
19#include "./vp9_thread.h"
20
21#if defined(__cplusplus) || defined(c_plusplus)
22extern "C" {
23#endif
24
25#if CONFIG_MULTITHREAD
26
27//------------------------------------------------------------------------------
28
29static THREADFN thread_loop(void *ptr) {    // thread loop
30  VP9Worker* const worker = (VP9Worker*)ptr;
31  int done = 0;
32  while (!done) {
33    pthread_mutex_lock(&worker->mutex_);
34    while (worker->status_ == OK) {   // wait in idling mode
35      pthread_cond_wait(&worker->condition_, &worker->mutex_);
36    }
37    if (worker->status_ == WORK) {
38      vp9_worker_execute(worker);
39      worker->status_ = OK;
40    } else if (worker->status_ == NOT_OK) {   // finish the worker
41      done = 1;
42    }
43    // signal to the main thread that we're done (for Sync())
44    pthread_cond_signal(&worker->condition_);
45    pthread_mutex_unlock(&worker->mutex_);
46  }
47  return THREAD_RETURN(NULL);    // Thread is finished
48}
49
50// main thread state control
51static void change_state(VP9Worker* const worker,
52                         VP9WorkerStatus new_status) {
53  // no-op when attempting to change state on a thread that didn't come up
54  if (worker->status_ < OK) return;
55
56  pthread_mutex_lock(&worker->mutex_);
57  // wait for the worker to finish
58  while (worker->status_ != OK) {
59    pthread_cond_wait(&worker->condition_, &worker->mutex_);
60  }
61  // assign new status and release the working thread if needed
62  if (new_status != OK) {
63    worker->status_ = new_status;
64    pthread_cond_signal(&worker->condition_);
65  }
66  pthread_mutex_unlock(&worker->mutex_);
67}
68
69#endif  // CONFIG_MULTITHREAD
70
71//------------------------------------------------------------------------------
72
73void vp9_worker_init(VP9Worker* const worker) {
74  memset(worker, 0, sizeof(*worker));
75  worker->status_ = NOT_OK;
76}
77
78int vp9_worker_sync(VP9Worker* const worker) {
79#if CONFIG_MULTITHREAD
80  change_state(worker, OK);
81#endif
82  assert(worker->status_ <= OK);
83  return !worker->had_error;
84}
85
86int vp9_worker_reset(VP9Worker* const worker) {
87  int ok = 1;
88  worker->had_error = 0;
89  if (worker->status_ < OK) {
90#if CONFIG_MULTITHREAD
91    if (pthread_mutex_init(&worker->mutex_, NULL) ||
92        pthread_cond_init(&worker->condition_, NULL)) {
93      return 0;
94    }
95    pthread_mutex_lock(&worker->mutex_);
96    ok = !pthread_create(&worker->thread_, NULL, thread_loop, worker);
97    if (ok) worker->status_ = OK;
98    pthread_mutex_unlock(&worker->mutex_);
99#else
100    worker->status_ = OK;
101#endif
102  } else if (worker->status_ > OK) {
103    ok = vp9_worker_sync(worker);
104  }
105  assert(!ok || (worker->status_ == OK));
106  return ok;
107}
108
109void vp9_worker_execute(VP9Worker* const worker) {
110  if (worker->hook != NULL) {
111    worker->had_error |= !worker->hook(worker->data1, worker->data2);
112  }
113}
114
115void vp9_worker_launch(VP9Worker* const worker) {
116#if CONFIG_MULTITHREAD
117  change_state(worker, WORK);
118#else
119  vp9_worker_execute(worker);
120#endif
121}
122
123void vp9_worker_end(VP9Worker* const worker) {
124  if (worker->status_ >= OK) {
125#if CONFIG_MULTITHREAD
126    change_state(worker, NOT_OK);
127    pthread_join(worker->thread_, NULL);
128    pthread_mutex_destroy(&worker->mutex_);
129    pthread_cond_destroy(&worker->condition_);
130#else
131    worker->status_ = NOT_OK;
132#endif
133  }
134  assert(worker->status_ == NOT_OK);
135}
136
137//------------------------------------------------------------------------------
138
139#if defined(__cplusplus) || defined(c_plusplus)
140}    // extern "C"
141#endif
142