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#include <mbgl/util/uv-worker.h>
#include <mbgl/util/uv-messenger.h>
#include <stdio.h>
#include <assert.h>
typedef struct uv__worker_item_s uv__worker_item_t;
struct uv__worker_item_s {
uv_worker_t *worker;
void *data;
uv_worker_cb work_cb;
uv_worker_after_cb after_work_cb;
};
typedef struct uv__worker_thread_s uv__worker_thread_t;
struct uv__worker_thread_s {
uv_worker_t *worker;
uv_thread_t thread;
};
void uv__worker_free_messenger(uv_messenger_t *msgr) {
free(msgr);
}
void uv__worker_thread_finished(uv__worker_thread_t *worker_thread) {
uv_worker_t *worker = worker_thread->worker;
#ifdef DEBUG
assert(uv_thread_self() == worker->thread_id);
#endif
// This should at most block very briefly. We are sending the termination
// notification as the last thing in the worker thread, so by now the thread
// has probably terminated already. If not, the waiting time should be
// extremely short.
uv_thread_join(&worker_thread->thread);
assert(worker->count > 0);
worker->count--;
if (worker->count == 0) {
uv_chan_destroy(&worker->chan);
uv_messenger_stop(worker->msgr, uv__worker_free_messenger);
if (worker->close_cb) {
worker->close_cb(worker);
}
}
}
void uv__worker_after(void *ptr) {
uv__worker_item_t *item = (uv__worker_item_t *)ptr;
if (item->work_cb) {
// We are finishing a regular work request.
if (item->after_work_cb) {
assert(item->after_work_cb);
item->after_work_cb(item->data);
}
uv_worker_t *worker = item->worker;
assert(worker->active_items > 0);
if (--worker->active_items == 0) {
uv_messenger_unref(worker->msgr);
}
} else {
// This is a worker thread termination.
uv__worker_thread_t *worker_thread = (uv__worker_thread_t *)item->data;
uv__worker_thread_finished(worker_thread);
free(worker_thread);
}
free(item);
}
void uv__worker_thread_loop(void *ptr) {
uv__worker_thread_t *worker_thread = (uv__worker_thread_t *)ptr;
uv_worker_t *worker = worker_thread->worker;
#ifdef __APPLE__
if (worker->name) {
pthread_setname_np(worker->name);
}
#endif
uv__worker_item_t *item = NULL;
while ((item = (uv__worker_item_t *)uv_chan_receive(&worker->chan)) != NULL) {
assert(item->work_cb);
item->work_cb(item->data);
// Trigger the after callback in the main thread.
uv_messenger_send(worker->msgr, item);
}
// Make sure to close all other workers too.
uv_chan_send(&worker->chan, NULL);
// Create a new worker item that acts as a terminate flag for this thread.
item = (uv__worker_item_t *)malloc(sizeof(uv__worker_item_t));
item->data = worker_thread;
item->work_cb = NULL;
item->after_work_cb = NULL;
uv_messenger_send(worker->msgr, item);
}
int uv_worker_init(uv_worker_t *worker, uv_loop_t *loop, int count, const char *name) {
#ifdef DEBUG
worker->thread_id = uv_thread_self();
#endif
worker->loop = loop;
worker->name = name;
worker->count = 0;
worker->close_cb = NULL;
worker->active_items = 0;
worker->msgr = (uv_messenger_t *)malloc(sizeof(uv_messenger_t));
int ret = uv_messenger_init(loop, worker->msgr, uv__worker_after);
if (ret < 0) {
free(worker->msgr);
return ret;
}
uv_messenger_unref(worker->msgr);
ret = uv_chan_init(&worker->chan);
if (ret < 0) return ret;
// Initialize all worker threads.
int i;
for (i = 0; i < count; i++) {
uv__worker_thread_t *worker_thread = (uv__worker_thread_t *)malloc(sizeof(uv__worker_thread_t));
worker_thread->worker = worker;
ret = uv_thread_create(&worker_thread->thread, uv__worker_thread_loop, worker_thread);
if (ret < 0) return ret;
worker->count++;
}
return 0;
}
void uv_worker_send(uv_worker_t *worker, void *data, uv_worker_cb work_cb,
uv_worker_after_cb after_work_cb) {
#ifdef DEBUG
assert(uv_thread_self() == worker->thread_id);
#endif
// It doesn't make sense to not provide a work callback. On the other hand, the after_work_cb
// may be NULL. In that case, there will be no callback called in the current thread and the
// worker item will instead be freed in the worker thread.
assert(work_cb);
uv__worker_item_t *item = (uv__worker_item_t *)malloc(sizeof(uv__worker_item_t));
item->worker = worker;
item->work_cb = work_cb;
item->after_work_cb = after_work_cb;
item->data = data;
uv_chan_send(&worker->chan, item);
if (worker->active_items++ == 0) {
uv_messenger_ref(worker->msgr);
}
}
void uv_worker_close(uv_worker_t *worker, uv_worker_close_cb close_cb) {
#ifdef DEBUG
assert(uv_thread_self() == worker->thread_id);
#endif
// Prevent double calling.
assert(worker->close_cb == NULL);
worker->close_cb = close_cb;
uv_chan_send(&worker->chan, NULL);
if (worker->active_items++ == 0) {
uv_messenger_ref(worker->msgr);
}
}
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