Sharvil Nanavati | c5856ba | 2014-06-23 12:25:40 -0700 | [diff] [blame] | 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 | |
Sharvil Nanavati | c11b407 | 2014-05-02 23:55:09 -0700 | [diff] [blame] | 19 | #pragma once |
| 20 | |
Sharvil Nanavati | c5856ba | 2014-06-23 12:25:40 -0700 | [diff] [blame] | 21 | #include <stdbool.h> |
Sharvil Nanavati | c11b407 | 2014-05-02 23:55:09 -0700 | [diff] [blame] | 22 | |
| 23 | struct fixed_queue_t; |
| 24 | typedef struct fixed_queue_t fixed_queue_t; |
| 25 | |
| 26 | typedef void (*fixed_queue_free_cb)(void *data); |
| 27 | |
Sharvil Nanavati | c5856ba | 2014-06-23 12:25:40 -0700 | [diff] [blame] | 28 | // Creates a new fixed queue with the given |capacity|. If more elements than |
| 29 | // |capacity| are added to the queue, the caller is blocked until space is |
| 30 | // made available in the queue. Returns NULL on failure. The caller must free |
| 31 | // the returned queue with |fixed_queue_free|. |
Sharvil Nanavati | c11b407 | 2014-05-02 23:55:09 -0700 | [diff] [blame] | 32 | fixed_queue_t *fixed_queue_new(size_t capacity); |
| 33 | |
| 34 | // Freeing a queue that is currently in use (i.e. has waiters |
Sharvil Nanavati | c5856ba | 2014-06-23 12:25:40 -0700 | [diff] [blame] | 35 | // blocked on it) results in undefined behaviour. |
Sharvil Nanavati | c11b407 | 2014-05-02 23:55:09 -0700 | [diff] [blame] | 36 | void fixed_queue_free(fixed_queue_t *queue, fixed_queue_free_cb free_cb); |
| 37 | |
Sharvil Nanavati | c5856ba | 2014-06-23 12:25:40 -0700 | [diff] [blame] | 38 | // Enqueues the given |data| into the |queue|. The caller will be blocked |
| 39 | // if nore more space is available in the queue. Neither |queue| nor |data| |
| 40 | // may be NULL. |
Sharvil Nanavati | c11b407 | 2014-05-02 23:55:09 -0700 | [diff] [blame] | 41 | void fixed_queue_enqueue(fixed_queue_t *queue, void *data); |
Sharvil Nanavati | c5856ba | 2014-06-23 12:25:40 -0700 | [diff] [blame] | 42 | |
| 43 | // Dequeues the next element from |queue|. If the queue is currently empty, |
| 44 | // this function will block the caller until an item is enqueued. This |
| 45 | // function will never return NULL. |queue| may not be NULL. |
Sharvil Nanavati | c11b407 | 2014-05-02 23:55:09 -0700 | [diff] [blame] | 46 | void *fixed_queue_dequeue(fixed_queue_t *queue); |
Sharvil Nanavati | c5856ba | 2014-06-23 12:25:40 -0700 | [diff] [blame] | 47 | |
| 48 | // Tries to enqueue |data| into the |queue|. This function will never block |
| 49 | // the caller. If the queue capacity would be exceeded by adding one more |
| 50 | // element, this function returns false immediately. Otherwise, this function |
| 51 | // returns true. Neither |queue| nor |data| may be NULL. |
| 52 | bool fixed_queue_try_enqueue(fixed_queue_t *queue, void *data); |
| 53 | |
| 54 | // Tries to dequeue an element from |queue|. This function will never block |
| 55 | // the caller. If the queue is empty, this function returns NULL immediately. |
| 56 | // Otherwise, the next element in the queue is returned. |queue| may not be |
| 57 | // NULL. |
| 58 | void *fixed_queue_try_dequeue(fixed_queue_t *queue); |
Sharvil Nanavati | ab606b5 | 2014-07-04 16:33:37 -0700 | [diff] [blame] | 59 | |
| 60 | // This function returns a valid file descriptor. Callers may perform one |
| 61 | // operation on the fd: select(2). If |select| indicates that the file |
| 62 | // descriptor is readable, the caller may call |fixed_queue_enqueue| without |
| 63 | // blocking. The caller must not close the returned file descriptor. |queue| |
| 64 | // may not be NULL. |
| 65 | int fixed_queue_get_enqueue_fd(const fixed_queue_t *queue); |
| 66 | |
| 67 | // This function returns a valid file descriptor. Callers may perform one |
| 68 | // operation on the fd: select(2). If |select| indicates that the file |
| 69 | // descriptor is readable, the caller may call |fixed_queue_dequeue| without |
| 70 | // blocking. The caller must not close the returned file descriptor. |queue| |
| 71 | // may not be NULL. |
| 72 | int fixed_queue_get_dequeue_fd(const fixed_queue_t *queue); |