src/lib/trace-ir/clock-snapshot.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
   5  */
   6
   7 #define BT_LOG_TAG "LIB/CLOCK-SNAPSHOT"
   8 #include "lib/logging.h"
   9
  10 #include "lib/assert-cond.h"
  11 #include "common/uuid.h"
  12 #include "clock-class.h"
  13 #include "clock-snapshot.h"
  14 #include <babeltrace2/trace-ir/clock-snapshot.h>
  15 #include "compat/compiler.h"
  16 #include <babeltrace2/types.h>
  17 #include "compat/string.h"
  18 #include <inttypes.h>
  19 #include "lib/object.h"
  20 #include "common/assert.h"
  21 #include "lib/func-status.h"
  22
  23 void bt_clock_snapshot_destroy(struct bt_clock_snapshot *clock_snapshot)
  24 {
  25         BT_ASSERT(clock_snapshot);
  26         BT_LIB_LOGD("Destroying clock snapshot: %!+k", clock_snapshot);
  27         BT_OBJECT_PUT_REF_AND_RESET(clock_snapshot->clock_class);
  28         g_free(clock_snapshot);
  29 }
  30
  31 struct bt_clock_snapshot *bt_clock_snapshot_new(
  32                 struct bt_clock_class *clock_class)
  33 {
  34         struct bt_clock_snapshot *ret = NULL;
  35
  36         BT_ASSERT(clock_class);
  37         BT_LIB_LOGD("Creating clock snapshot object: %![cc-]+K=",
  38                 clock_class);
  39         ret = g_new0(struct bt_clock_snapshot, 1);
  40         if (!ret) {
  41                 BT_LIB_LOGE_APPEND_CAUSE(
  42                         "Failed to allocate one clock snapshot.");
  43                 goto end;
  44         }
  45
  46         bt_object_init_unique(&ret->base);
  47         ret->clock_class = clock_class;
  48         bt_object_get_ref_no_null_check(clock_class);
  49         bt_clock_class_freeze(clock_class);
  50         BT_LIB_LOGD("Created clock snapshot object: %!+k", ret);
  51
  52 end:
  53         return ret;
  54 }
  55
  56 struct bt_clock_snapshot *bt_clock_snapshot_create(
  57                 struct bt_clock_class *clock_class)
  58 {
  59         struct bt_clock_snapshot *clock_snapshot = NULL;
  60
  61         BT_ASSERT_DBG(clock_class);
  62         clock_snapshot = bt_object_pool_create_object(&clock_class->cs_pool);
  63         if (!clock_snapshot) {
  64                 BT_LIB_LOGE_APPEND_CAUSE(
  65                         "Cannot allocate one clock snapshot from clock class's clock snapshot pool: "
  66                         "%![cc-]+K", clock_class);
  67                 goto end;
  68         }
  69
  70         if (G_LIKELY(!clock_snapshot->clock_class)) {
  71                 clock_snapshot->clock_class = clock_class;
  72                 bt_object_get_ref_no_null_check(clock_class);
  73         }
  74
  75 end:
  76         return clock_snapshot;
  77 }
  78
  79 void bt_clock_snapshot_recycle(struct bt_clock_snapshot *clock_snapshot)
  80 {
  81         struct bt_clock_class *clock_class;
  82
  83         BT_ASSERT_DBG(clock_snapshot);
  84         BT_LIB_LOGD("Recycling clock snapshot: %!+k", clock_snapshot);
  85
  86         /*
  87          * Those are the important ordered steps:
  88          *
  89          * 1. Reset the clock snapshot object, but do NOT put its clock
  90          *    class's reference. This clock class contains the pool to
  91          *    which we're about to recycle this clock snapshot object,
  92          *    so we must guarantee its existence thanks to this existing
  93          *    reference.
  94          *
  95          * 2. Move the clock class reference to our `clock_class`
  96          *    variable so that we can set the clock snapshot's clock
  97          *    class member to NULL before recycling it. We CANNOT do
  98          *    this after we put the clock class reference because this
  99          *    bt_object_put_ref() could destroy the clock class, also
 100          *    destroying its clock snapshot pool, thus also destroying
 101          *    our clock snapshot object (this would result in an invalid
 102          *    write access).
 103          *
 104          * 3. Recycle the clock snapshot object.
 105          *
 106          * 4. Put our clock class reference.
 107          */
 108         bt_clock_snapshot_reset(clock_snapshot);
 109         clock_class = clock_snapshot->clock_class;
 110         BT_ASSERT_DBG(clock_class);
 111         clock_snapshot->clock_class = NULL;
 112         bt_object_pool_recycle_object(&clock_class->cs_pool, clock_snapshot);
 113         bt_object_put_ref(clock_class);
 114 }
 115
 116 BT_EXPORT
 117 uint64_t bt_clock_snapshot_get_value(
 118                 const struct bt_clock_snapshot *clock_snapshot)
 119 {
 120         BT_ASSERT_PRE_DEV_CS_NON_NULL(clock_snapshot);
 121         BT_ASSERT_DBG(clock_snapshot->is_set);
 122         return clock_snapshot->value_cycles;
 123 }
 124
 125 BT_EXPORT
 126 enum bt_clock_snapshot_get_ns_from_origin_status
 127 bt_clock_snapshot_get_ns_from_origin(
 128                 const struct bt_clock_snapshot *clock_snapshot,
 129                 int64_t *ret_value_ns)
 130 {
 131         int ret = BT_FUNC_STATUS_OK;
 132
 133         BT_ASSERT_PRE_DEV_NO_ERROR();
 134         BT_ASSERT_PRE_DEV_CS_NON_NULL(clock_snapshot);
 135         BT_ASSERT_PRE_DEV_NON_NULL("value-ns-output", ret_value_ns,
 136                 "Value (ns) (output)");
 137         BT_ASSERT_DBG(clock_snapshot->is_set);
 138
 139         if (clock_snapshot->ns_from_origin_overflows) {
 140                 BT_LIB_LOGE_APPEND_CAUSE(
 141                         "Clock snapshot, once converted to nanoseconds from origin, "
 142                         "overflows the signed 64-bit integer range: "
 143                         "%![cs-]+k", clock_snapshot);
 144                 ret = BT_FUNC_STATUS_OVERFLOW_ERROR;
 145                 goto end;
 146         }
 147
 148         *ret_value_ns = clock_snapshot->ns_from_origin;
 149
 150 end:
 151         return ret;
 152 }
 153
 154 BT_EXPORT
 155 const struct bt_clock_class *bt_clock_snapshot_borrow_clock_class_const(
 156                 const struct bt_clock_snapshot *clock_snapshot)
 157 {
 158         BT_ASSERT_PRE_DEV_CS_NON_NULL(clock_snapshot);
 159         return clock_snapshot->clock_class;
 160 }