OVMS3-idf/components/bt/bluedroid/osi/future.c
wangmengyang bde768f13c 1. Recover "future_t" model implementation using semaphore to allow for blocking function
2. Recover BTU task start-up/shut-down procedure according to original bluedroid implementation
2016-10-10 21:34:21 +08:00

100 lines
2.5 KiB
C

/******************************************************************************
*
* 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 "bt_osi_future"
// #include <assert.h>
#include "bt_trace.h"
#include "allocator.h"
#include "future.h"
#include "osi.h"
//#include "osi/include/log.h"
#include "osi_arch.h"
struct future_t {
bool ready_can_be_called;
osi_sem_t semaphore; // NULL semaphore means immediate future
void *result;
};
static void future_free(future_t *future);
future_t *future_new(void) {
future_t *ret = osi_calloc(sizeof(future_t));
if (!ret) {
LOG_ERROR("%s unable to allocate memory for return value.", __func__);
goto error;
}
if (osi_sem_new(&ret->semaphore, 1, 0)!=0) {
LOG_ERROR("%s unable to allocate memory for the semaphore.", __func__);
goto error;
}
ret->ready_can_be_called = true;
return ret;
error:;
future_free(ret);
return NULL;
}
future_t *future_new_immediate(void *value) {
future_t *ret = osi_calloc(sizeof(future_t));
if (!ret) {
LOG_ERROR("%s unable to allocate memory for return value.", __func__);
goto error;
}
ret->result = value;
ret->ready_can_be_called = false;
return ret;
error:;
future_free(ret);
return NULL;
}
void future_ready(future_t *future, void *value) {
assert(future != NULL);
assert(future->ready_can_be_called);
future->ready_can_be_called = false;
future->result = value;
osi_sem_signal(&future->semaphore);
}
void *future_await(future_t *future) {
assert(future != NULL);
// If the future is immediate, it will not have a semaphore
if (future->semaphore)
osi_sem_wait(&future->semaphore, 0);
void *result = future->result;
future_free(future);
return result;
}
static void future_free(future_t *future) {
if (!future)
return;
if (!future->semaphore)
osi_sem_free(&future->semaphore);
osi_free(future);
}