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// Copyright 2013 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Multi-threaded worker
//
// Original source:
// http://git.chromium.org/webm/libwebp.git
// 100644 blob 264210ba2807e4da47eb5d18c04cf869d89b9784 src/utils/thread.c
#include <assert.h>
#include <string.h> // for memset()
#include "./vpx_thread.h"
#include "vpx_mem/vpx_mem.h"
#if CONFIG_MULTITHREAD
struct VPxWorkerImpl {
pthread_mutex_t mutex_;
pthread_cond_t condition_;
pthread_t thread_;
};
//------------------------------------------------------------------------------
static void execute(VPxWorker *const worker); // Forward declaration.
static THREADFN thread_loop(void *ptr) {
VPxWorker *const worker = (VPxWorker*)ptr;
int done = 0;
while (!done) {
pthread_mutex_lock(&worker->impl_->mutex_);
while (worker->status_ == OK) { // wait in idling mode
pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
}
if (worker->status_ == WORK) {
execute(worker);
worker->status_ = OK;
} else if (worker->status_ == NOT_OK) { // finish the worker
done = 1;
}
// signal to the main thread that we're done (for sync())
pthread_cond_signal(&worker->impl_->condition_);
pthread_mutex_unlock(&worker->impl_->mutex_);
}
return THREAD_RETURN(NULL); // Thread is finished
}
// main thread state control
static void change_state(VPxWorker *const worker,
VPxWorkerStatus new_status) {
// No-op when attempting to change state on a thread that didn't come up.
// Checking status_ without acquiring the lock first would result in a data
// race.
if (worker->impl_ == NULL) return;
pthread_mutex_lock(&worker->impl_->mutex_);
if (worker->status_ >= OK) {
// wait for the worker to finish
while (worker->status_ != OK) {
pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
}
// assign new status and release the working thread if needed
if (new_status != OK) {
worker->status_ = new_status;
pthread_cond_signal(&worker->impl_->condition_);
}
}
pthread_mutex_unlock(&worker->impl_->mutex_);
}
#endif // CONFIG_MULTITHREAD
//------------------------------------------------------------------------------
static void init(VPxWorker *const worker) {
memset(worker, 0, sizeof(*worker));
worker->status_ = NOT_OK;
}
static int sync(VPxWorker *const worker) {
#if CONFIG_MULTITHREAD
change_state(worker, OK);
#endif
assert(worker->status_ <= OK);
return !worker->had_error;
}
static int reset(VPxWorker *const worker) {
int ok = 1;
worker->had_error = 0;
if (worker->status_ < OK) {
#if CONFIG_MULTITHREAD
worker->impl_ = (VPxWorkerImpl*)vpx_calloc(1, sizeof(*worker->impl_));
if (worker->impl_ == NULL) {
return 0;
}
if (pthread_mutex_init(&worker->impl_->mutex_, NULL)) {
goto Error;
}
if (pthread_cond_init(&worker->impl_->condition_, NULL)) {
pthread_mutex_destroy(&worker->impl_->mutex_);
goto Error;
}
pthread_mutex_lock(&worker->impl_->mutex_);
ok = !pthread_create(&worker->impl_->thread_, NULL, thread_loop, worker);
if (ok) worker->status_ = OK;
pthread_mutex_unlock(&worker->impl_->mutex_);
if (!ok) {
pthread_mutex_destroy(&worker->impl_->mutex_);
pthread_cond_destroy(&worker->impl_->condition_);
Error:
vpx_free(worker->impl_);
worker->impl_ = NULL;
return 0;
}
#else
worker->status_ = OK;
#endif
} else if (worker->status_ > OK) {
ok = sync(worker);
}
assert(!ok || (worker->status_ == OK));
return ok;
}
static void execute(VPxWorker *const worker) {
if (worker->hook != NULL) {
worker->had_error |= !worker->hook(worker->data1, worker->data2);
}
}
static void launch(VPxWorker *const worker) {
#if CONFIG_MULTITHREAD
change_state(worker, WORK);
#else
execute(worker);
#endif
}
static void end(VPxWorker *const worker) {
#if CONFIG_MULTITHREAD
if (worker->impl_ != NULL) {
change_state(worker, NOT_OK);
pthread_join(worker->impl_->thread_, NULL);
pthread_mutex_destroy(&worker->impl_->mutex_);
pthread_cond_destroy(&worker->impl_->condition_);
vpx_free(worker->impl_);
worker->impl_ = NULL;
}
#else
worker->status_ = NOT_OK;
assert(worker->impl_ == NULL);
#endif
assert(worker->status_ == NOT_OK);
}
//------------------------------------------------------------------------------
static VPxWorkerInterface g_worker_interface = {
init, reset, sync, launch, execute, end
};
int vpx_set_worker_interface(const VPxWorkerInterface* const winterface) {
if (winterface == NULL ||
winterface->init == NULL || winterface->reset == NULL ||
winterface->sync == NULL || winterface->launch == NULL ||
winterface->execute == NULL || winterface->end == NULL) {
return 0;
}
g_worker_interface = *winterface;
return 1;
}
const VPxWorkerInterface *vpx_get_worker_interface(void) {
return &g_worker_interface;
}
//------------------------------------------------------------------------------
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