1 /****************************************************************************** 2 * 3 * Copyright (C) 2014 Google, Inc. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ******************************************************************************/ 18 19 #define LOG_TAG "bt_osi_future" 20 21 #include "osi/include/future.h" 22 23 #include <assert.h> 24 25 #include "osi/include/allocator.h" 26 #include "osi/include/log.h" 27 #include "osi/include/osi.h" 28 #include "osi/include/semaphore.h" 29 30 struct future_t { 31 bool ready_can_be_called; 32 semaphore_t *semaphore; // NULL semaphore means immediate future 33 void *result; 34 }; 35 36 static void future_free(future_t *future); 37 38 future_t *future_new(void) { 39 future_t *ret = osi_calloc(sizeof(future_t)); 40 41 ret->semaphore = semaphore_new(0); 42 if (!ret->semaphore) { 43 LOG_ERROR(LOG_TAG, "%s unable to allocate memory for the semaphore.", __func__); 44 goto error; 45 } 46 47 ret->ready_can_be_called = true; 48 return ret; 49 error:; 50 future_free(ret); 51 return NULL; 52 } 53 54 future_t *future_new_immediate(void *value) { 55 future_t *ret = osi_calloc(sizeof(future_t)); 56 57 ret->result = value; 58 ret->ready_can_be_called = false; 59 return ret; 60 } 61 62 void future_ready(future_t *future, void *value) { 63 assert(future != NULL); 64 assert(future->ready_can_be_called); 65 66 future->ready_can_be_called = false; 67 future->result = value; 68 semaphore_post(future->semaphore); 69 } 70 71 void *future_await(future_t *future) { 72 assert(future != NULL); 73 74 // If the future is immediate, it will not have a semaphore 75 if (future->semaphore) 76 semaphore_wait(future->semaphore); 77 78 void *result = future->result; 79 future_free(future); 80 return result; 81 } 82 83 static void future_free(future_t *future) { 84 if (!future) 85 return; 86 87 semaphore_free(future->semaphore); 88 osi_free(future); 89 } 90
