src/lib/trace-ir/event.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
   5  * Copyright 2013, 2014 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   6  */
   7
   8 #ifndef BABELTRACE_TRACE_IR_EVENT_INTERNAL_H
   9 #define BABELTRACE_TRACE_IR_EVENT_INTERNAL_H
  10
  11 /* Protection: this file uses BT_LIB_LOG*() macros directly */
  12 #ifndef BT_LIB_LOG_SUPPORTED
  13 # error Please include "lib/logging.h" before including this file.
  14 #endif
  15
  16 #include "lib/assert-cond.h"
  17 #include <babeltrace2/value.h>
  18 #include <babeltrace2/trace-ir/stream-class.h>
  19 #include <babeltrace2/trace-ir/stream.h>
  20 #include <babeltrace2/trace-ir/packet.h>
  21 #include <babeltrace2/trace-ir/field.h>
  22 #include "lib/object.h"
  23 #include "common/assert.h"
  24 #include <glib.h>
  25 #include <stdbool.h>
  26
  27 #include "event-class.h"
  28 #include "field.h"
  29 #include "packet.h"
  30 #include "stream.h"
  31
  32 #define BT_ASSERT_PRE_DEV_EVENT_HOT(_event)                             \
  33         BT_ASSERT_PRE_DEV_HOT(((const struct bt_event *) (_event)),     \
  34                 "Event", ": %!+e", (_event))
  35
  36 struct bt_event {
  37         struct bt_object base;
  38
  39         /* Owned by this */
  40         struct bt_event_class *class;
  41
  42         /* Owned by this (can be `NULL`) */
  43         struct bt_packet *packet;
  44
  45         /* Owned by this */
  46         struct bt_stream *stream;
  47
  48         struct bt_field *common_context_field;
  49         struct bt_field *specific_context_field;
  50         struct bt_field *payload_field;
  51         bool frozen;
  52 };
  53
  54 void bt_event_destroy(struct bt_event *event);
  55
  56 struct bt_event *bt_event_new(struct bt_event_class *event_class);
  57
  58 void _bt_event_set_is_frozen(const struct bt_event *event, bool is_frozen);
  59
  60 #ifdef BT_DEV_MODE
  61 # define bt_event_set_is_frozen         _bt_event_set_is_frozen
  62 #else
  63 # define bt_event_set_is_frozen(_event, _is_frozen)
  64 #endif
  65
  66 __attribute__((unused))
  67 static inline
  68 void _bt_event_reset_dev_mode(struct bt_event *event)
  69 {
  70         BT_ASSERT_DBG(event);
  71
  72         if (event->common_context_field) {
  73                 bt_field_set_is_frozen(
  74                         event->common_context_field, false);
  75                 bt_field_reset(
  76                         event->common_context_field);
  77         }
  78
  79         if (event->specific_context_field) {
  80                 bt_field_set_is_frozen(
  81                         event->specific_context_field, false);
  82                 bt_field_reset(event->specific_context_field);
  83         }
  84
  85         if (event->payload_field) {
  86                 bt_field_set_is_frozen(
  87                         event->payload_field, false);
  88                 bt_field_reset(event->payload_field);
  89         }
  90 }
  91
  92 #ifdef BT_DEV_MODE
  93 # define bt_event_reset_dev_mode        _bt_event_reset_dev_mode
  94 #else
  95 # define bt_event_reset_dev_mode(_x)
  96 #endif
  97
  98 static inline
  99 void bt_event_reset(struct bt_event *event)
 100 {
 101         BT_ASSERT_DBG(event);
 102         BT_LIB_LOGD("Resetting event: %!+e", event);
 103         bt_event_set_is_frozen(event, false);
 104         bt_object_put_ref_no_null_check(&event->stream->base);
 105         event->stream = NULL;
 106
 107         if (event->packet) {
 108                 bt_object_put_ref_no_null_check(&event->packet->base);
 109                 event->packet = NULL;
 110         }
 111 }
 112
 113 static inline
 114 void bt_event_recycle(struct bt_event *event)
 115 {
 116         struct bt_event_class *event_class;
 117
 118         BT_ASSERT_DBG(event);
 119         BT_LIB_LOGD("Recycling event: %!+e", event);
 120
 121         /*
 122          * Those are the important ordered steps:
 123          *
 124          * 1. Reset the event object (put any permanent reference it
 125          *    has, unfreeze it and its fields in developer mode, etc.),
 126          *    but do NOT put its class's reference. This event class
 127          *    contains the pool to which we're about to recycle this
 128          *    event object, so we must guarantee its existence thanks
 129          *    to this existing reference.
 130          *
 131          * 2. Move the event class reference to our `event_class`
 132          *    variable so that we can set the event's class member
 133          *    to NULL before recycling it. We CANNOT do this after
 134          *    we put the event class reference because this bt_object_put_ref()
 135          *    could destroy the event class, also destroying its
 136          *    event pool, thus also destroying our event object (this
 137          *    would result in an invalid write access).
 138          *
 139          * 3. Recycle the event object.
 140          *
 141          * 4. Put our event class reference.
 142          */
 143         bt_event_reset(event);
 144         event_class = event->class;
 145         BT_ASSERT_DBG(event_class);
 146         event->class = NULL;
 147         bt_object_pool_recycle_object(&event_class->event_pool, event);
 148         bt_object_put_ref_no_null_check(&event_class->base);
 149 }
 150
 151 #endif /* BABELTRACE_TRACE_IR_EVENT_INTERNAL_H */