include/babeltrace/plugin/notification/iterator.h

   1 #ifndef BABELTRACE_PLUGIN_NOTIFICATION_ITERATOR_H
   2 #define BABELTRACE_PLUGIN_NOTIFICATION_ITERATOR_H
   3
   4 /*
   5  * BabelTrace - Plug-in Notification Iterator
   6  *
   7  * Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   8  *
   9  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a copy
  12  * of this software and associated documentation files (the "Software"), to deal
  13  * in the Software without restriction, including without limitation the rights
  14  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15  * copies of the Software, and to permit persons to whom the Software is
  16  * furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  26  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  27  * SOFTWARE.
  28  */
  29
  30 #include <stdint.h>
  31
  32 #ifdef __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 struct bt_notification;
  37 struct bt_notification_iterator;
  38
  39 /**
  40  * Status code. Errors are always negative.
  41  */
  42 enum bt_notification_iterator_status {
  43         /** Invalid arguments. */
  44         /* -22 for compatibility with -EINVAL */
  45         BT_NOTIFICATION_ITERATOR_STATUS_INVAL = -22,
  46
  47         /** End of trace. */
  48         BT_NOTIFICATION_ITERATOR_STATUS_EOT = -3,
  49
  50         /** General error. */
  51         BT_NOTIFICATION_ITERATOR_STATUS_ERROR = -2,
  52
  53         /** Unsupported iterator feature. */
  54         BT_NOTIFICATION_ITERATOR_STATUS_UNSUPPORTED = -1,
  55
  56         /** No error, okay. */
  57         BT_NOTIFICATION_ITERATOR_STATUS_OK = 0,
  58 };
  59
  60 /**
  61  * Notification iterator seek reference.
  62  */
  63 enum bt_notification_iterator_seek_type {
  64         /** Seek at a time relative to the beginning of the trace. */
  65         BT_NOTIFICATION_ITERATOR_SEEK_TYPE_BEGIN = 0,
  66
  67         /** Seek at a time relative to the current position. */
  68         BT_NOTIFICATION_ITERATOR_SEEK_TYPE_CURRENT = 1,
  69
  70         /** Seek at a time relative to the end of the trace. */
  71         BT_NOTIFICATION_ITERATOR_SEEK_TYPE_END = 1,
  72 };
  73
  74 /**
  75  * Get current notification at iterator's position.
  76  *
  77  * This functions will <b>not</b> advance the cursor's position.
  78  * The returned notification's reference count is already incremented.
  79  *
  80  * @param iterator      Iterator instance
  81  * @returns             Returns a bt_notification instance
  82  *
  83  * @see bt_notification_put()
  84  */
  85 extern struct bt_notification *bt_notification_iterator_get_notification(
  86                 struct bt_notification_iterator *iterator);
  87
  88 /**
  89  * Advance the iterator's position forward.
  90  *
  91  * This function can be called repeatedly to iterate through the iterator's
  92  * associated trace.
  93  *
  94  * @param iterator      Iterator instance
  95  * @returns             Returns a bt_notification instance
  96  *
  97  * @see bt_notification_iterator_get_notification()
  98  */
  99 extern enum bt_notification_iterator_status
 100 bt_notification_iterator_next(struct bt_notification_iterator *iterator);
 101
 102 /**
 103  * Seek iterator to position.
 104  *
 105  * Sets the iterator's position for the trace associated with the iterator.
 106  * The new position is computed by adding \p time to the position specified
 107  * by \p whence.
 108  *
 109  * @param iterator      Iterator instance
 110  * @param whence        One of #bt_notification_iterator_seek_type values.
 111  * @returns             One of #bt_notification_iterator_status values;
 112  *                      if \iterator does not support seeking,
 113  *                      #BT_NOTIFICATION_ITERATOR_STATUS_UNSUPPORTED is
 114  *                      returned.
 115  *
 116  * @see bt_notification_iterator_get_notification()
 117  */
 118 extern enum bt_notification_iterator_status *bt_notification_iterator_seek(
 119                 struct bt_notification_iterator *iterator, int whence,
 120                 int64_t time);
 121
 122 /**
 123  * Increments the reference count of \p iterator.
 124  *
 125  * @param iterator      Iterator of which to increment the reference count
 126  *
 127  * @see bt_notification_iterator_put()
 128  */
 129 extern void bt_notification_iterator_get(
 130                 struct bt_notification_iterator *iterator);
 131
 132 /**
 133  * Decrements the reference count of \p iterator, destroying it when this
 134  * count reaches 0.
 135  *
 136  * @param iterator      Iterator of which to decrement the reference count
 137  *
 138  * @see bt_notification_iterator_get()
 139  */
 140 extern void bt_notification_iterator_put(
 141                 struct bt_notification_iterator *iterator);
 142
 143 #ifdef __cplusplus
 144 }
 145 #endif
 146
 147 #endif /* BABELTRACE_PLUGIN_NOTIFICATION_ITERATOR_H */