1 /****************************************************************************** 2 * 3 * Copyright 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 #pragma once 20 21 typedef struct future_t future_t; 22 23 #define FUTURE_SUCCESS ((void*)1) 24 #define FUTURE_FAIL ((void*)0) 25 26 // Constructs a new future_t object. Returns NULL on failure. 27 future_t* future_new(void); 28 29 // Constructs a new future_t object with an immediate |value|. No waiting will 30 // occur in the call to |future_await| because the value is already present. 31 // Returns NULL on failure. 32 future_t* future_new_immediate(void* value); 33 34 // Signals that the |future| is ready, passing |value| back to the context 35 // waiting for the result. Must only be called once for every future. 36 // |future| may not be NULL. 37 void future_ready(future_t* future, void* value); 38 39 // Waits for the |future| to be ready. Returns the value set in |future_ready|. 40 // Frees the future before return. |future| may not be NULL. 41 void* future_await(future_t* async_result); 42