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/******************************************************************************
*
* Copyright (C) 2014 Google, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#define LOG_TAG "osi_thread"
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/types.h>
#include <utils/Log.h>
#include "fixed_queue.h"
#include "reactor.h"
#include "semaphore.h"
#include "thread.h"
struct thread_t {
pthread_t pthread;
pid_t tid;
char name[THREAD_NAME_MAX + 1];
reactor_t *reactor;
fixed_queue_t *work_queue;
};
struct start_arg {
thread_t *thread;
semaphore_t *start_sem;
int error;
};
typedef struct {
thread_fn func;
void *context;
} work_item_t;
static void *run_thread(void *start_arg);
static void work_queue_read_cb(void *context);
static const size_t WORK_QUEUE_CAPACITY = 128;
thread_t *thread_new(const char *name) {
assert(name != NULL);
// Start is on the stack, but we use a semaphore, so it's safe
thread_t *ret = calloc(1, sizeof(thread_t));
if (!ret)
goto error;
ret->reactor = reactor_new();
if (!ret->reactor)
goto error;
ret->work_queue = fixed_queue_new(WORK_QUEUE_CAPACITY);
if (!ret->work_queue)
goto error;
struct start_arg start;
start.start_sem = semaphore_new(0);
if (!start.start_sem)
goto error;
strncpy(ret->name, name, THREAD_NAME_MAX);
start.thread = ret;
start.error = 0;
pthread_create(&ret->pthread, NULL, run_thread, &start);
semaphore_wait(start.start_sem);
semaphore_free(start.start_sem);
if (start.error)
goto error;
return ret;
error:;
if (ret) {
fixed_queue_free(ret->work_queue, free);
reactor_free(ret->reactor);
}
free(ret);
return NULL;
}
void thread_free(thread_t *thread) {
if (!thread)
return;
thread_stop(thread);
pthread_join(thread->pthread, NULL);
fixed_queue_free(thread->work_queue, free);
reactor_free(thread->reactor);
free(thread);
}
bool thread_post(thread_t *thread, thread_fn func, void *context) {
assert(thread != NULL);
assert(func != NULL);
// TODO(sharvil): if the current thread == |thread| and we've run out
// of queue space, we should abort this operation, otherwise we'll
// deadlock.
// Queue item is freed either when the queue itself is destroyed
// or when the item is removed from the queue for dispatch.
work_item_t *item = (work_item_t *)malloc(sizeof(work_item_t));
if (!item) {
ALOGE("%s unable to allocate memory: %s", __func__, strerror(errno));
return false;
}
item->func = func;
item->context = context;
fixed_queue_enqueue(thread->work_queue, item);
return true;
}
void thread_stop(thread_t *thread) {
assert(thread != NULL);
reactor_stop(thread->reactor);
}
const char *thread_name(const thread_t *thread) {
assert(thread != NULL);
return thread->name;
}
static void *run_thread(void *start_arg) {
assert(start_arg != NULL);
struct start_arg *start = start_arg;
thread_t *thread = start->thread;
assert(thread != NULL);
if (prctl(PR_SET_NAME, (unsigned long)thread->name) == -1) {
ALOGE("%s unable to set thread name: %s", __func__, strerror(errno));
start->error = errno;
semaphore_post(start->start_sem);
return NULL;
}
thread->tid = gettid();
semaphore_post(start->start_sem);
reactor_object_t work_queue_object;
work_queue_object.context = thread->work_queue;
work_queue_object.fd = fixed_queue_get_dequeue_fd(thread->work_queue);
work_queue_object.interest = REACTOR_INTEREST_READ;
work_queue_object.read_ready = work_queue_read_cb;
reactor_register(thread->reactor, &work_queue_object);
reactor_start(thread->reactor);
// Make sure we dispatch all queued work items before exiting the thread.
// This allows a caller to safely tear down by enqueuing a teardown
// work item and then joining the thread.
size_t count = 0;
work_item_t *item = fixed_queue_try_dequeue(thread->work_queue);
while (item && count <= WORK_QUEUE_CAPACITY) {
item->func(item->context);
free(item);
item = fixed_queue_try_dequeue(thread->work_queue);
++count;
}
if (count > WORK_QUEUE_CAPACITY)
ALOGD("%s growing event queue on shutdown.", __func__);
return NULL;
}
static void work_queue_read_cb(void *context) {
assert(context != NULL);
fixed_queue_t *queue = (fixed_queue_t *)context;
work_item_t *item = fixed_queue_dequeue(queue);
item->func(item->context);
free(item);
}
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