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 "common/macros.h"
  18 #include <babeltrace2/value.h>
  19 #include <babeltrace2/trace-ir/stream-class.h>
  20 #include <babeltrace2/trace-ir/stream.h>
  21 #include <babeltrace2/trace-ir/packet.h>
  22 #include <babeltrace2/trace-ir/field.h>
  23 #include "lib/object.h"
  24 #include "common/assert.h"
  25 #include <glib.h>
  26 #include <stdbool.h>
  27
  28 #include "event-class.h"
  29 #include "field.h"
  30 #include "field-wrapper.h"
  31 #include "packet.h"
  32 #include "stream.h"
  33
  34 #define BT_ASSERT_PRE_DEV_EVENT_HOT(_event)                             \
  35         BT_ASSERT_PRE_DEV_HOT(((const struct bt_event *) (_event)),     \
  36                 "Event", ": %!+e", (_event))
  37
  38 struct bt_event {
  39         struct bt_object base;
  40
  41         /* Owned by this */
  42         struct bt_event_class *class;
  43
  44         /* Owned by this (can be `NULL`) */
  45         struct bt_packet *packet;
  46
  47         /* Owned by this */
  48         struct bt_stream *stream;
  49
  50         struct bt_field *common_context_field;
  51         struct bt_field *specific_context_field;
  52         struct bt_field *payload_field;
  53         bool frozen;
  54 };
  55
  56 void bt_event_destroy(struct bt_event *event);
  57
  58 struct bt_event *bt_event_new(struct bt_event_class *event_class);
  59
  60 void _bt_event_set_is_frozen(const struct bt_event *event, bool is_frozen);
  61
  62 #ifdef BT_DEV_MODE
  63 # define bt_event_set_is_frozen         _bt_event_set_is_frozen
  64 #else
  65 # define bt_event_set_is_frozen(_event, _is_frozen)
  66 #endif
  67
  68 __attribute__((unused))
  69 static inline
  70 void _bt_event_reset_dev_mode(struct bt_event *event)
  71 {
  72         BT_ASSERT_DBG(event);
  73
  74         if (event->common_context_field) {
  75                 bt_field_set_is_frozen(
  76                         event->common_context_field, false);
  77                 bt_field_reset(
  78                         event->common_context_field);
  79         }
  80
  81         if (event->specific_context_field) {
  82                 bt_field_set_is_frozen(
  83                         event->specific_context_field, false);
  84                 bt_field_reset(event->specific_context_field);
  85         }
  86
  87         if (event->payload_field) {
  88                 bt_field_set_is_frozen(
  89                         event->payload_field, false);
  90                 bt_field_reset(event->payload_field);
  91         }
  92 }
  93
  94 #ifdef BT_DEV_MODE
  95 # define bt_event_reset_dev_mode        _bt_event_reset_dev_mode
  96 #else
  97 # define bt_event_reset_dev_mode(_x)
  98 #endif
  99
 100 static inline
 101 void bt_event_reset(struct bt_event *event)
 102 {
 103         BT_ASSERT_DBG(event);
 104         BT_LIB_LOGD("Resetting event: %!+e", event);
 105         bt_event_set_is_frozen(event, false);
 106         bt_object_put_ref_no_null_check(&event->stream->base);
 107         event->stream = NULL;
 108
 109         if (event->packet) {
 110                 bt_object_put_ref_no_null_check(&event->packet->base);
 111                 event->packet = NULL;
 112         }
 113 }
 114
 115 static inline
 116 void bt_event_recycle(struct bt_event *event)
 117 {
 118         struct bt_event_class *event_class;
 119
 120         BT_ASSERT_DBG(event);
 121         BT_LIB_LOGD("Recycling event: %!+e", event);
 122
 123         /*
 124          * Those are the important ordered steps:
 125          *
 126          * 1. Reset the event object (put any permanent reference it
 127          *    has, unfreeze it and its fields in developer mode, etc.),
 128          *    but do NOT put its class's reference. This event class
 129          *    contains the pool to which we're about to recycle this
 130          *    event object, so we must guarantee its existence thanks
 131          *    to this existing reference.
 132          *
 133          * 2. Move the event class reference to our `event_class`
 134          *    variable so that we can set the event's class member
 135          *    to NULL before recycling it. We CANNOT do this after
 136          *    we put the event class reference because this bt_object_put_ref()
 137          *    could destroy the event class, also destroying its
 138          *    event pool, thus also destroying our event object (this
 139          *    would result in an invalid write access).
 140          *
 141          * 3. Recycle the event object.
 142          *
 143          * 4. Put our event class reference.
 144          */
 145         bt_event_reset(event);
 146         event_class = event->class;
 147         BT_ASSERT_DBG(event_class);
 148         event->class = NULL;
 149         bt_object_pool_recycle_object(&event_class->event_pool, event);
 150         bt_object_put_ref_no_null_check(&event_class->base);
 151 }
 152
 153 #endif /* BABELTRACE_TRACE_IR_EVENT_INTERNAL_H */