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