src/third_party/libvpx/source/libvpx/vp9/decoder/vp9_thread.c

   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)
  22 extern "C" {
  23 #endif
  24
  25 #if CONFIG_MULTITHREAD
  26
  27 //------------------------------------------------------------------------------
  28
  29 static 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
  51 static 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
  73 void vp9_worker_init(VP9Worker* const worker) {
  74   memset(worker, 0, sizeof(*worker));
  75   worker->status_ = NOT_OK;
  76 }
  77
  78 int 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
  86 int 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
 109 void vp9_worker_execute(VP9Worker* const worker) {
 110   if (worker->hook != NULL) {
 111     worker->had_error |= !worker->hook(worker->data1, worker->data2);
 112   }
 113 }
 114
 115 void 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
 123 void 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