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 21 #include <stdbool.h> 22 #include <stdint.h> 23 24 #include "osi/include/osi.h" 25 26 // This module implements the Reactor pattern. 27 // See http://en.wikipedia.org/wiki/Reactor_pattern for details. 28 29 typedef struct reactor_t reactor_t; 30 typedef struct reactor_object_t reactor_object_t; 31 32 // Enumerates the reasons a reactor has stopped. 33 typedef enum { 34 REACTOR_STATUS_STOP, // |reactor_stop| was called. 35 REACTOR_STATUS_ERROR, // there was an error during the operation. 36 REACTOR_STATUS_DONE, // the reactor completed its work (for the _run_once* variants). 37 } reactor_status_t; 38 39 // Creates a new reactor object. Returns NULL on failure. The returned object 40 // must be freed by calling |reactor_free|. 41 reactor_t *reactor_new(void); 42 43 // Frees a reactor object created with |reactor_new|. |reactor| may be NULL. 44 void reactor_free(reactor_t *reactor); 45 46 // Starts the reactor. This function blocks the caller until |reactor_stop| is called 47 // from another thread or in a callback. |reactor| may not be NULL. 48 reactor_status_t reactor_start(reactor_t *reactor); 49 50 // Runs one iteration of the reactor. This function blocks until at least one registered object 51 // becomes ready. |reactor| may not be NULL. 52 reactor_status_t reactor_run_once(reactor_t *reactor); 53 54 // Immediately unblocks the reactor. This function is safe to call from any thread. 55 // |reactor| may not be NULL. 56 void reactor_stop(reactor_t *reactor); 57 58 // Registers a file descriptor with the reactor. The file descriptor, |fd|, must be valid 59 // when this function is called and its ownership is not transferred to the reactor. The 60 // |context| variable is a user-defined opaque handle that is passed back to the |read_ready| 61 // and |write_ready| functions. It is not copied or even dereferenced by the reactor so it 62 // may contain any value including NULL. The |read_ready| and |write_ready| arguments are 63 // optional and may be NULL. This function returns an opaque object that represents the 64 // file descriptor's registration with the reactor. When the caller is no longer interested 65 // in events on the |fd|, it must free the returned object by calling |reactor_unregister|. 66 reactor_object_t *reactor_register(reactor_t *reactor, 67 int fd, void *context, 68 void (*read_ready)(void *context), 69 void (*write_ready)(void *context)); 70 71 // Changes the subscription mode for the file descriptor represented by |object|. If the 72 // caller has already registered a file descriptor with a reactor, has a valid |object|, 73 // and decides to change the |read_ready| and/or |write_ready| callback routines, they 74 // can call this routine. Returns true if the subscription was changed, false otherwise. 75 // |object| may not be NULL, |read_ready| and |write_ready| may be NULL. 76 bool reactor_change_registration(reactor_object_t *object, 77 void (*read_ready)(void *context), 78 void (*write_ready)(void *context)); 79 80 // Unregisters a previously registered file descriptor with its reactor. |obj| may not be NULL. 81 // |obj| is invalid after calling this function so the caller must drop all references to it. 82 void reactor_unregister(reactor_object_t *obj); 83
