From 1bcffbdd260ac600336bb74db592b2481bb6a2e6 Mon Sep 17 00:00:00 2001
From: Robert Newson <rnewson@apache.org>
Date: Sat, 1 Nov 2014 16:32:16 +0000
Subject: [PATCH] update_histogram with timing of a function

---
 src/couch_stats.erl | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/couch_stats.erl b/src/couch_stats.erl
index b4b3b22..59854e2 100644
--- a/src/couch_stats.erl
+++ b/src/couch_stats.erl
@@ -87,8 +87,19 @@ decrement_counter(Name) ->
 decrement_counter(Name, Value) ->
     notify(Name, {dec, Value}).
 
--spec update_histogram(any(), number()) -> response().
-update_histogram(Name, Value) ->
+-spec update_histogram(any(), number()) -> response();
+                      (any(), function()) -> any().
+update_histogram(Name, Fun) when is_function(Fun, 0) ->
+    Begin = os:timestamp(),
+    Result = Fun(),
+    Duration = timer:now_diff(os:timestamp(), Begin) div 1000,
+    case notify(Name, Duration) of
+        ok ->
+            Result;
+        {error, unknown_metric} ->
+            throw({unknown_metric, Name})
+    end;
+update_histogram(Name, Value) when is_number(Value) ->
     notify(Name, Value).
 
 -spec update_gauge(any(), number()) -> response().