52 lines
1.8 KiB
C
52 lines
1.8 KiB
C
/******************************************************************************
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*
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* Copyright (C) 2014 Google, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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#ifndef __FUTURE_H__
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#define __FUTURE_H__
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// #pragma once
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#include "osi_arch.h"
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struct future {
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bool ready_can_be_called;
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osi_sem_t semaphore; // NULL semaphore means immediate future
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void *result;
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};
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typedef struct future future_t;
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#define FUTURE_SUCCESS ((void *)1)
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#define FUTURE_FAIL ((void *)0)
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// Constructs a new future_t object. Returns NULL on failure.
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future_t *future_new(void);
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// Constructs a new future_t object with an immediate |value|. No waiting will
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// occur in the call to |future_await| because the value is already present.
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// Returns NULL on failure.
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future_t *future_new_immediate(void *value);
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// Signals that the |future| is ready, passing |value| back to the context
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// waiting for the result. Must only be called once for every future.
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// |future| may not be NULL.
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void future_ready(future_t *future, void *value);
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// Waits for the |future| to be ready. Returns the value set in |future_ready|.
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// Frees the future before return. |future| may not be NULL.
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void *future_await(future_t *async_result);
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#endif /* __FUTURE_H__ */
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