esp-idf/components/bt/common/osi/include/osi/future.h
2019-06-30 16:39:00 +08:00

54 lines
1.9 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.
*
******************************************************************************/
#ifndef __FUTURE_H__
#define __FUTURE_H__
#include "osi/semaphore.h"
struct future {
bool ready_can_be_called;
osi_sem_t semaphore; // NULL semaphore means immediate future
void *result;
};
typedef struct future future_t;
#define FUTURE_SUCCESS ((void *)1)
#define FUTURE_FAIL ((void *)0)
// Constructs a new future_t object. Returns NULL on failure.
future_t *future_new(void);
// Constructs a new future_t object with an immediate |value|. No waiting will
// occur in the call to |future_await| because the value is already present.
// Returns NULL on failure.
future_t *future_new_immediate(void *value);
// Signals that the |future| is ready, passing |value| back to the context
// waiting for the result. Must only be called once for every future.
// |future| may not be NULL.
void future_ready(future_t *future, void *value);
// Waits for the |future| to be ready. Returns the value set in |future_ready|.
// Frees the future before return. |future| may not be NULL.
void *future_await(future_t *async_result);
//Free the future if this "future" is not used
void future_free(future_t *future);
#endif /* __FUTURE_H__ */