trace: Add support for integer counters

This will be used in GTask.

glib/gtrace-private.h

@@ -67,4 +67,15 @@ void (g_trace_mark) (gint64       begin_time_nsec,
 #endif
 #endif
 
+guint   (g_trace_define_int64_counter) (const char *group,
+                                        const char *name,
+                                        const char *description);
+void    (g_trace_set_int64_counter)    (guint       id,
+                                        gint64      value);
+
+#ifndef HAVE_SYSPROF
+#define g_trace_define_int64_counter(g, n, d) ((guint) -1)
+#define g_trace_set_int64_counter(i,v)
+#endif
+
 G_END_DECLS

glib/gtrace.c

@@ -96,3 +96,82 @@ void
   va_end (args);
 #endif  /* HAVE_SYSPROF */
 }
+
+/*
+ * g_trace_define_int64_counter:
+ * @group: name of the group for categorising this counter
+ * @name: name of the counter
+ * @description: description for the counter
+ *
+ * Defines a new counter with integer values.
+ *
+ * The name should be unique within all counters defined with
+ * the same @group. The description will be shown in the sysprof UI.
+ *
+ * To add entries for this counter to a trace, use
+ * g_trace_set_int64_counter().
+ *
+ * Returns: ID of the counter, for use with g_trace_set_int64_counter(),
+ *     guaranteed to never be zero
+ *
+ * Since: 2.68
+ */
+guint
+(g_trace_define_int64_counter) (const char *group,
+                                const char *name,
+                                const char *description)
+{
+#ifdef HAVE_SYSPROF
+  SysprofCaptureCounter counter;
+
+  counter.id = sysprof_collector_request_counters (1);
+
+  /* sysprof not enabled? */
+  if (counter.id == 0)
+    return (guint) -1;
+
+  counter.type = SYSPROF_CAPTURE_COUNTER_INT64;
+  counter.value.v64 = 0;
+  g_strlcpy (counter.category, group, sizeof counter.category);
+  g_strlcpy (counter.name, name, sizeof counter.name);
+  g_strlcpy (counter.description, description, sizeof counter.description);
+
+  sysprof_collector_define_counters (&counter, 1);
+
+  g_assert (counter.id != 0);
+
+  return counter.id;
+#else
+  return (guint) -1;
+#endif
+}
+
+/*
+ * g_trace_set_int64_counter:
+ * @id: ID of the counter
+ * @val: the value to set the counter to
+ *
+ * Adds a counter value to a trace.
+ *
+ * The ID must be obtained via g_trace_define_int64_counter()
+ * before using this function.
+ *
+ * Since: 2.68
+ */
+void
+(g_trace_set_int64_counter) (guint  id,
+                             gint64 val)
+{
+#ifdef HAVE_SYSPROF
+  SysprofCaptureCounterValue value;
+
+  g_return_if_fail (id != 0);
+
+  /* Ignore setting the counter if we failed to define it in the first place. */
+  if (id == (guint) -1)
+    return;
+
+  value.v64 = val;
+  sysprof_collector_set_counters (&id, &value, 1);
+#endif
+}