merge bug21428 into default

2 files changed, 28 insertions, 1 deletions

diff --git a/src/rabbit_misc.erl b/src/rabbit_misc.erl
index 13a2aa05ec..ed8b4165d2 100644
--- a/src/rabbit_misc.erl
+++ b/src/rabbit_misc.erl
@@ -53,6 +53,7 @@
 -export([append_file/2, ensure_parent_dirs_exist/1]).
 -export([format_stderr/2]).
 -export([start_applications/1, stop_applications/1]).
+-export([unfold/2, ceil/1]).
 
 -import(mnesia).
 -import(lists).
@@ -116,7 +117,9 @@
 -spec(format_stderr/2 :: (string(), [any()]) -> 'ok').
 -spec(start_applications/1 :: ([atom()]) -> 'ok').
 -spec(stop_applications/1 :: ([atom()]) -> 'ok').
-
+-spec(unfold/2  :: (fun ((A) -> ({'true', B, A} | 'false')), A) -> {[B], A}).
+-spec(ceil/1 :: (number()) -> number()).
+              
 -endif.
 
 %%----------------------------------------------------------------------------
@@ -446,3 +449,18 @@ stop_applications(Apps) ->
                         cannot_stop_application,
                         Apps).
 
+unfold(Fun, Init) ->
+    unfold(Fun, [], Init).
+
+unfold(Fun, Acc, Init) ->
+    case Fun(Init) of
+        {true, E, I} -> unfold(Fun, [E|Acc], I);
+        false -> {Acc, Init}
+    end.
+
+ceil(N) ->
+    T = trunc(N),
+    case N - T of
+        0 -> N;
+        _ -> 1 + T
+    end.
diff --git a/src/rabbit_tests.erl b/src/rabbit_tests.erl
index 5e1cdfb18a..e7aa97e5ed 100644
--- a/src/rabbit_tests.erl
+++ b/src/rabbit_tests.erl
@@ -49,6 +49,7 @@ test_content_prop_roundtrip(Datum, Binary) ->
 
 all_tests() ->
     passed = test_priority_queue(),
+    passed = test_unfold(),
     passed = test_parsing(),
     passed = test_topic_matching(),
     passed = test_log_management(),
@@ -182,6 +183,14 @@ test_simple_n_element_queue(N) ->
     {true, false, N, ToListRes, Items} = test_priority_queue(Q),
     passed.
 
+test_unfold() ->
+    {[], test} = rabbit_misc:unfold(fun (V) -> false end, test),
+    List = lists:seq(2,20,2),
+    {List, 0} = rabbit_misc:unfold(fun (0) -> false;
+                                       (N) -> {true, N*2, N-1}
+                                   end, 10),
+    passed.
+
 test_parsing() ->
     passed = test_content_properties(),
     passed.