include/babeltrace/plugin/notification/heap.h

   1 #ifndef BT_NOTIFICATION_HEAP_H
   2 #define BT_NOTIFICATION_HEAP_H
   3
   4 /*
   5  * Babeltrace - Notification Heap
   6  *
   7  * Copyright (c) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  * Copyright (c) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26  * SOFTWARE.
  27  */
  28
  29 #include <stddef.h>
  30 #include <stdbool.h>
  31 #include <babeltrace/plugin/notification/notification.h>
  32 #include <babeltrace/babeltrace-internal.h>
  33
  34 /**
  35  * bt_notification_time_compare - Compare two notifications' timestamps
  36  *
  37  * Compare two notifications in the time domain. Return true if 'a' happened
  38  * prior to 'b'. In the case where both notifications are deemed to have
  39  * happened at the same time, an implementation-defined critarion shall be
  40  * used to order the notifications. This criterion shall ensure a consistent
  41  * ordering over multiple runs.
  42  */
  43 typedef bool (*bt_notification_time_compare_func)(
  44                 struct bt_notification *a, struct bt_notification *b,
  45                 void *user_data);
  46
  47 /**
  48  * bt_notification_heap_create - create a new bt_notification heap.
  49  *
  50  * @comparator: Function to use for notification comparisons.
  51  *
  52  * Returns a new notification heap, NULL on error.
  53  */
  54 extern struct bt_notification_heap *bt_notification_heap_create(
  55                 bt_notification_time_compare_func comparator, void *user_data);
  56
  57 /**
  58  * bt_notification_heap_insert - insert an element into the heap
  59  *
  60  * @heap: the heap to be operated on
  61  * @notification: the notification to add
  62  *
  63  * Insert a notification into the heap.
  64  *
  65  * Returns 0 on success, a negative value on error.
  66  */
  67 extern int bt_notification_heap_insert(struct bt_notification_heap *heap,
  68                 struct bt_notification *notification);
  69
  70 /**
  71  * bt_notification_heap_peek - return the element on top of the heap.
  72  *
  73  * @heap: the heap to be operated on
  74  *
  75  * Returns the top element of the heap, without performing any modification
  76  * to the heap structure. Returns NULL if the heap is empty. The returned
  77  * notification must be bt_put() by the caller.
  78  */
  79 extern struct bt_notification *bt_notification_heap_peek(
  80                 struct bt_notification_heap *heap);
  81
  82 /**
  83  * bt_notification_heap_pop - remove the element sitting on top of the heap.
  84  * @heap: the heap to be operated on
  85  *
  86  * Returns the top element of the heap. The element is removed from the
  87  * heap. Returns NULL if the heap is empty. The returned notification must be
  88  * bt_put() by the caller.
  89  */
  90 extern struct bt_notification *bt_notification_heap_pop(
  91                 struct bt_notification_heap *heap);
  92
  93 #endif /* BT_NOTIFICATION_HEAP_H */