| /****************************************************************************** |
| * |
| * 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 "osi/include/future.h" |
| |
| #include <assert.h> |
| |
| #include "osi/include/allocator.h" |
| #include "osi/include/log.h" |
| #include "osi/include/osi.h" |
| #include "osi/include/semaphore.h" |
| |
| struct future_t { |
| bool ready_can_be_called; |
| semaphore_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(LOG_TAG, "%s unable to allocate memory for return value.", __func__); |
| goto error; |
| } |
| |
| ret->semaphore = semaphore_new(0); |
| if (!ret->semaphore) { |
| LOG_ERROR(LOG_TAG, "%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(LOG_TAG, "%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; |
| semaphore_post(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) |
| semaphore_wait(future->semaphore); |
| |
| void *result = future->result; |
| future_free(future); |
| return result; |
| } |
| |
| static void future_free(future_t *future) { |
| if (!future) |
| return; |
| |
| semaphore_free(future->semaphore); |
| osi_free(future); |
| } |