add stats functions to print just name or value

include/cc_metric.h

@@ -136,6 +136,8 @@ struct metric {
 };
 
 void metric_reset(struct metric sarr[], unsigned int nmetric);
+size_t metric_print_name(char *buf, size_t nbuf, char *fmt, struct metric *m);
+size_t metric_print_value(char *buf, size_t nbuf, char *fmt, struct metric *m);
 size_t metric_print(char *buf, size_t nbuf, char *fmt, struct metric *m);
 void metric_describe_all(struct metric metrics[], unsigned int nmetric);
 

src/stats/cc_metric.c

@@ -58,38 +58,68 @@ metric_reset(struct metric sarr[], unsigned int n)
     }
 }
 
-size_t
-metric_print(char *buf, size_t nbuf, char *fmt, struct metric *m)
+static void
+_metric_value(char *buf, struct metric *m)
 {
-    char val_buf[VALUE_PRINT_LEN];
-
-    if (m == NULL) {
-        return 0;
-    }
-
     switch(m->type) {
     case METRIC_COUNTER:
         /**
          * not using cc_print_uint64, since it would complicate implementation
          * and negatively impact readability, and since this function should not
          * be called often enough to make it absolutely performance critical.
          */
-        cc_scnprintf(val_buf, VALUE_PRINT_LEN, "%llu", __atomic_load_n(
-                    &m->counter, __ATOMIC_RELAXED));
+        cc_scnprintf(buf, VALUE_PRINT_LEN, "%llu", __atomic_load_n(&m->counter,
+                    __ATOMIC_RELAXED));
         break;
 
     case METRIC_GAUGE:
-        cc_scnprintf(val_buf, VALUE_PRINT_LEN, "%lld", __atomic_load_n(
-                    &m->gauge, __ATOMIC_RELAXED));
+        cc_scnprintf(buf, VALUE_PRINT_LEN, "%lld", __atomic_load_n(&m->gauge,
+                    __ATOMIC_RELAXED));
         break;
 
     case METRIC_FPN:
-        cc_scnprintf(val_buf, VALUE_PRINT_LEN, "%f", m->fpn);
+        cc_scnprintf(buf, VALUE_PRINT_LEN, "%f", m->fpn);
         break;
 
     default:
         NOT_REACHED();
     }
+}
+
+size_t
+metric_print_name(char *buf, size_t nbuf, char *fmt, struct metric *m)
+{
+    if (m == NULL) {
+        return 0;
+    }
+
+    return cc_scnprintf(buf, nbuf, fmt, m->name);
+}
+
+size_t
+metric_print_value(char *buf, size_t nbuf, char *fmt, struct metric *m)
+{
+    char val_buf[VALUE_PRINT_LEN];
+
+    if (m == NULL) {
+        return 0;
+    }
+
+    _metric_value(val_buf, m);
+
+    return cc_scnprintf(buf, nbuf, fmt, val_buf);
+}
+
+size_t
+metric_print(char *buf, size_t nbuf, char *fmt, struct metric *m)
+{
+    char val_buf[VALUE_PRINT_LEN];
+
+    if (m == NULL) {
+        return 0;
+    }
+
+    _metric_value(val_buf, m);
 
     return cc_scnprintf(buf, nbuf, fmt, m->name, val_buf);
 }