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#pragma once
20
21typedef 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.
27future_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.
32future_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.
37void 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.
41void *future_await(future_t *async_result);
42