[06/50] couch commit: updated refs/remotes/origin/import to 09c6556

[be...@apache.org]

Extend _sum to operate on JSON Objects

A map function that emits JSON objects as values can now be used with
the builtin _sum function.  In contrast to our support for JSON arrays
(which can be freely mixed with numbers), this extension requires an
all-or-nothing approach - either emit only objects or do not emit any at
all.  Moreover, all the fields inside the object must have values that
are numbers or arrays of numbers.

TODO use proper instead of writing explicit unit test cases

BugzID: 14798


Project: http://git-wip-us.apache.org/repos/asf/couchdb-couch/repo
Commit: http://git-wip-us.apache.org/repos/asf/couchdb-couch/commit/5a2ec4f5
Tree: http://git-wip-us.apache.org/repos/asf/couchdb-couch/tree/5a2ec4f5
Diff: http://git-wip-us.apache.org/repos/asf/couchdb-couch/diff/5a2ec4f5

Branch: refs/remotes/origin/import
Commit: 5a2ec4f50cbac04d8572cde13a118b3d0341fad6
Parents: f8fb11a
Author: Adam Kocoloski <ad...@cloudant.com>
Authored: Fri Dec 7 11:07:20 2012 -0800
Committer: Paul J. Davis <pa...@gmail.com>
Committed: Tue Feb 4 17:03:23 2014 -0600

----------------------------------------------------------------------
 src/couch_query_servers.erl | 73 +++++++++++++++++++++++++++++-----------
 1 file changed, 53 insertions(+), 20 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/couchdb-couch/blob/5a2ec4f5/src/couch_query_servers.erl
----------------------------------------------------------------------
diff --git a/src/couch_query_servers.erl b/src/couch_query_servers.erl
index eb41e27..e420ce9 100644
--- a/src/couch_query_servers.erl
+++ b/src/couch_query_servers.erl
@@ -24,6 +24,11 @@
 
 -include_lib("couch/include/couch_db.hrl").
 
+-define(SUMERROR, <<"The _sum function requires that map values be numbers, "
+    "arrays of numbers, or objects. Objects cannot be mixed with other data "
+    "structures. Objects can be arbitrarily nested, provided that the values "
+    "for all fields are themselves numbers, arrays of numbers, or objects.">>).
+
 % https://gist.github.com/df10284c76d85f988c3f
 -define(SUMREGEX, {re_pattern,3,0,<<69,82,67,80,194,0,0,0,8,0,0,0,5,0,0,0,3,0,
 2,0,0,0,125,2,48,0,9,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,118,97,108,
@@ -204,29 +209,42 @@ builtin_reduce(Re, [<<"_stats",_/binary>>|BuiltinReds], KVs, Acc) ->
     builtin_reduce(Re, BuiltinReds, KVs, [Stats|Acc]).
 
 builtin_sum_rows(KVs) ->
-    lists:foldl(fun
-        ([_Key, Value], Acc) when is_number(Value), is_number(Acc) ->
-            Acc + Value;
-        ([_Key, Value], Acc) when is_list(Value), is_list(Acc) ->
-            sum_terms(Acc, Value);
-        ([_Key, Value], Acc) when is_number(Value), is_list(Acc) ->
-            sum_terms(Acc, [Value]);
-        ([_Key, Value], Acc) when is_list(Value), is_number(Acc) ->
-            sum_terms([Acc], Value);
-        (_Else, _Acc) ->
-            throw({invalid_value, <<"builtin _sum function requires map values to be numbers or lists of numbers">>})
-    end, 0, KVs).
-
-sum_terms([], []) ->
+    lists:foldl(fun([_Key, Value], Acc) -> sum_values(Value, Acc) end, 0, KVs).
+
+sum_values({Props}, {AccProps}) ->
+    {sum_objects(lists:sort(Props), lists:sort(AccProps))};
+sum_values(Value, Acc) when is_number(Value), is_number(Acc) ->
+    Acc + Value;
+sum_values(Value, Acc) when is_list(Value), is_list(Acc) ->
+    sum_arrays(Acc, Value);
+sum_values(Value, Acc) when is_number(Value), is_list(Acc) ->
+    sum_arrays(Acc, [Value]);
+sum_values(Value, Acc) when is_list(Value), is_number(Acc) ->
+    sum_arrays([Acc], Value);
+sum_values(_Else, _Acc) ->
+    throw({invalid_value, ?SUMERROR}).
+
+sum_objects([{K1, V1} | Rest1], [{K1, V2} | Rest2]) ->
+    [{K1, sum_values(V1, V2)} | sum_objects(Rest1, Rest2)];
+sum_objects([{K1, V1} | Rest1], [{K2, V2} | Rest2]) when K1 < K2 ->
+    [{K1, V1}, {K2, V2} | sum_objects(Rest1, Rest2)];
+sum_objects([{K1, V1} | Rest1], [{K2, V2} | Rest2]) when K1 > K2 ->
+    [{K2, V2}, {K1, V1} | sum_objects(Rest1, Rest2)];
+sum_objects([], Rest) ->
+    Rest;
+sum_objects(Rest, []) ->
+    Rest.
+
+sum_arrays([], []) ->
     [];
-sum_terms([_|_]=Xs, []) ->
+sum_arrays([_|_]=Xs, []) ->
     Xs;
-sum_terms([], [_|_]=Ys) ->
+sum_arrays([], [_|_]=Ys) ->
     Ys;
-sum_terms([X|Xs], [Y|Ys]) when is_number(X), is_number(Y) ->
-    [X+Y | sum_terms(Xs,Ys)];
-sum_terms(_, _) ->
-    throw({invalid_value, <<"builtin _sum function requires map values to be numbers or lists of numbers">>}).
+sum_arrays([X|Xs], [Y|Ys]) when is_number(X), is_number(Y) ->
+    [X+Y | sum_arrays(Xs,Ys)];
+sum_arrays(_, _) ->
+    throw({invalid_value, ?SUMERROR}).
 
 
 builtin_stats(reduce, [[_,First]|Rest]) ->
@@ -397,3 +415,18 @@ ret_os_process(Proc) ->
     true = gen_server:call(couch_proc_manager, {ret_proc, Proc}, infinity),
     catch unlink(Proc#proc.pid),
     ok.
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+
+sum_values_test() ->
+    ?assertEqual(3, sum_values(1, 2)),
+    ?assertEqual([2,4,6], sum_values(1, [1,4,6])),
+    ?assertEqual([3,5,7], sum_values([3,2,4], [0,3,3])),
+    X = {[{<<"a">>,1}, {<<"b">>,[1,2]}, {<<"c">>, {[{<<"d">>,3}]}}]},
+    Y = {[{<<"a">>,2}, {<<"b">>,3}, {<<"c">>, {[{<<"e">>, 5}]}}]},
+    Z = {[{<<"a">>,3}, {<<"b">>,[4,2]}, {<<"c">>, {[{<<"d">>,3},{<<"e">>,5}]}}]},
+    ?assertEqual(Z, sum_values(X, Y)),
+    ?assertEqual(Z, sum_values(Y, X)).
+
+-endif.