82 lines
3.8 KiB
C
82 lines
3.8 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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#pragma once
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#include <stdbool.h>
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#include <stdint.h>
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#include "osi/include/osi.h"
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// This module implements the Reactor pattern.
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// See http://en.wikipedia.org/wiki/Reactor_pattern for details.
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typedef struct reactor_t reactor_t;
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typedef struct reactor_object_t reactor_object_t;
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// Enumerates the reasons a reactor has stopped.
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typedef enum {
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REACTOR_STATUS_STOP, // |reactor_stop| was called.
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REACTOR_STATUS_ERROR, // there was an error during the operation.
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REACTOR_STATUS_DONE, // the reactor completed its work (for the _run_once* variants).
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} reactor_status_t;
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// Creates a new reactor object. Returns NULL on failure. The returned object
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// must be freed by calling |reactor_free|.
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reactor_t *reactor_new(void);
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// Frees a reactor object created with |reactor_new|. |reactor| may be NULL.
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void reactor_free(reactor_t *reactor);
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// Starts the reactor. This function blocks the caller until |reactor_stop| is called
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// from another thread or in a callback. |reactor| may not be NULL.
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reactor_status_t reactor_start(reactor_t *reactor);
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// Runs one iteration of the reactor. This function blocks until at least one registered object
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// becomes ready. |reactor| may not be NULL.
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reactor_status_t reactor_run_once(reactor_t *reactor);
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// Immediately unblocks the reactor. This function is safe to call from any thread.
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// |reactor| may not be NULL.
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void reactor_stop(reactor_t *reactor);
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// Registers a file descriptor with the reactor. The file descriptor, |fd|, must be valid
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// when this function is called and its ownership is not transferred to the reactor. The
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// |context| variable is a user-defined opaque handle that is passed back to the |read_ready|
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// and |write_ready| functions. It is not copied or even dereferenced by the reactor so it
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// may contain any value including NULL. The |read_ready| and |write_ready| arguments are
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// optional and may be NULL. This function returns an opaque object that represents the
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// file descriptor's registration with the reactor. When the caller is no longer interested
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// in events on the |fd|, it must free the returned object by calling |reactor_unregister|.
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reactor_object_t *reactor_register(reactor_t *reactor,
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int fd, void *context,
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void (*read_ready)(void *context),
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void (*write_ready)(void *context));
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// Changes the subscription mode for the file descriptor represented by |object|. If the
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// caller has already registered a file descriptor with a reactor, has a valid |object|,
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// and decides to change the |read_ready| and/or |write_ready| callback routines, they
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// can call this routine. Returns true if the subscription was changed, false otherwise.
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// |object| may not be NULL, |read_ready| and |write_ready| may be NULL.
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bool reactor_change_registration(reactor_object_t *object,
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void (*read_ready)(void *context),
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void (*write_ready)(void *context));
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// Unregisters a previously registered file descriptor with its reactor. |obj| may not be NULL.
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// |obj| is invalid after calling this function so the caller must drop all references to it.
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void reactor_unregister(reactor_object_t *obj);
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