src/lib/metrics/metrics_store_entry.c

   1 /* Copyright (c) 2020, The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 /**
   5  * @file metrics_store_entry.c
   6  * @brief Metrics store entry which contains the gathered data.
   7  **/
   8
   9 #define METRICS_STORE_ENTRY_PRIVATE
  10
  11 #include <string.h>
  12
  13 #include "orconfig.h"
  14
  15 #include "lib/container/smartlist.h"
  16 #include "lib/log/util_bug.h"
  17 #include "lib/malloc/malloc.h"
  18
  19 #include "lib/metrics/metrics_store_entry.h"
  20
  21 /*
  22  * Public API.
  23  */
  24
  25 /** Return newly allocated store entry of type COUNTER. */
  26 metrics_store_entry_t *
  27 metrics_store_entry_new(const metrics_type_t type, const char *name,
  28                         const char *help)
  29 {
  30   metrics_store_entry_t *entry = tor_malloc_zero(sizeof(*entry));
  31
  32   tor_assert(name);
  33
  34   entry->type = type;
  35   entry->name = tor_strdup(name);
  36   entry->labels = smartlist_new();
  37   if (help) {
  38     entry->help = tor_strdup(help);
  39   }
  40
  41   return entry;
  42 }
  43
  44 /** Free a store entry. */
  45 void
  46 metrics_store_entry_free_(metrics_store_entry_t *entry)
  47 {
  48   if (!entry) {
  49     return;
  50   }
  51   SMARTLIST_FOREACH(entry->labels, char *, l, tor_free(l));
  52   smartlist_free(entry->labels);
  53   tor_free(entry->name);
  54   tor_free(entry->help);
  55   tor_free(entry);
  56 }
  57
  58 /** Update a store entry with value. */
  59 void
  60 metrics_store_entry_update(metrics_store_entry_t *entry, const int64_t value)
  61 {
  62   tor_assert(entry);
  63
  64   switch (entry->type) {
  65   case METRICS_TYPE_COUNTER:
  66     /* Counter can ONLY be positive. */
  67     if (BUG(value < 0)) {
  68       return;
  69     }
  70     entry->u.counter.value += value;
  71     break;
  72   case METRICS_TYPE_GAUGE:
  73     /* Gauge can increment or decrement. And can be positive or negative. */
  74     entry->u.gauge.value += value;
  75     break;
  76   }
  77 }
  78
  79 /** Reset a store entry that is set its metric data to 0. */
  80 void
  81 metrics_store_entry_reset(metrics_store_entry_t *entry)
  82 {
  83   tor_assert(entry);
  84   /* Everything back to 0. */
  85   memset(&entry->u, 0, sizeof(entry->u));
  86 }
  87
  88 /** Return store entry value. */
  89 int64_t
  90 metrics_store_entry_get_value(const metrics_store_entry_t *entry)
  91 {
  92   tor_assert(entry);
  93
  94   switch (entry->type) {
  95   case METRICS_TYPE_COUNTER:
  96     if (entry->u.counter.value > INT64_MAX) {
  97       return INT64_MAX;
  98     }
  99     return entry->u.counter.value;
 100   case METRICS_TYPE_GAUGE:
 101     return entry->u.gauge.value;
 102   }
 103
 104   // LCOV_EXCL_START
 105   tor_assert_unreached();
 106   // LCOV_EXCL_STOP
 107 }
 108
 109 /** Add a label into the given entry.*/
 110 void
 111 metrics_store_entry_add_label(metrics_store_entry_t *entry,
 112                               const char *label)
 113 {
 114   tor_assert(entry);
 115   tor_assert(label);
 116
 117   smartlist_add(entry->labels, tor_strdup(label));
 118 }
 119
 120 /** Return true iff the given entry has the given label. */
 121 bool
 122 metrics_store_entry_has_label(const metrics_store_entry_t *entry,
 123                               const char *label)
 124 {
 125   tor_assert(entry);
 126   tor_assert(label);
 127
 128   return smartlist_contains_string(entry->labels, label);
 129 }