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% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License. You may obtain a copy of
% the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
-module(couch_query_servers).
-export([start_doc_map/2, map_docs/2, stop_doc_map/1]).
-export([reduce/3, rereduce/3,validate_doc_update/5]).
-export([filter_docs/5]).
-export([with_ddoc_proc/2, proc_prompt/2, ddoc_prompt/3, ddoc_proc_prompt/3, json_doc/1]).
-export([get_os_process/1, ret_os_process/1]).
% -export([test/0]).
-include("couch_db.hrl").
start_doc_map(Lang, Functions) ->
Proc = get_os_process(Lang),
lists:foreach(fun(FunctionSource) ->
true = proc_prompt(Proc, [<<"add_fun">>, FunctionSource])
end, Functions),
{ok, Proc}.
map_docs(Proc, Docs) ->
% send the documents
Results = lists:map(
fun(Doc) ->
Json = couch_doc:to_json_obj(Doc, []),
FunsResults = proc_prompt(Proc, [<<"map_doc">>, Json]),
% the results are a json array of function map yields like this:
% [FunResults1, FunResults2 ...]
% where funresults is are json arrays of key value pairs:
% [[Key1, Value1], [Key2, Value2]]
% Convert the key, value pairs to tuples like
% [{Key1, Value1}, {Key2, Value2}]
lists:map(
fun(FunRs) ->
[list_to_tuple(FunResult) || FunResult <- FunRs]
end,
FunsResults)
end,
Docs),
{ok, Results}.
stop_doc_map(nil) ->
ok;
stop_doc_map(Proc) ->
ok = ret_os_process(Proc).
group_reductions_results([]) ->
[];
group_reductions_results(List) ->
{Heads, Tails} = lists:foldl(
fun([H|T], {HAcc,TAcc}) ->
{[H|HAcc], [T|TAcc]}
end, {[], []}, List),
case Tails of
[[]|_] -> % no tails left
[Heads];
_ ->
[Heads | group_reductions_results(Tails)]
end.
rereduce(_Lang, [], _ReducedValues) ->
{ok, []};
rereduce(Lang, RedSrcs, ReducedValues) ->
Grouped = group_reductions_results(ReducedValues),
Results = lists:zipwith(
fun
(<<"_", _/binary>> = FunSrc, Values) ->
{ok, [Result]} = builtin_reduce(rereduce, [FunSrc], [[[], V] || V <- Values], []),
Result;
(FunSrc, Values) ->
os_rereduce(Lang, [FunSrc], Values)
end, RedSrcs, Grouped),
{ok, Results}.
reduce(_Lang, [], _KVs) ->
{ok, []};
reduce(Lang, RedSrcs, KVs) ->
{OsRedSrcs, BuiltinReds} = lists:partition(fun
(<<"_", _/binary>>) -> false;
(_OsFun) -> true
end, RedSrcs),
{ok, OsResults} = os_reduce(Lang, OsRedSrcs, KVs),
{ok, BuiltinResults} = builtin_reduce(reduce, BuiltinReds, KVs, []),
recombine_reduce_results(RedSrcs, OsResults, BuiltinResults, []).
recombine_reduce_results([], [], [], Acc) ->
{ok, lists:reverse(Acc)};
recombine_reduce_results([<<"_", _/binary>>|RedSrcs], OsResults, [BRes|BuiltinResults], Acc) ->
recombine_reduce_results(RedSrcs, OsResults, BuiltinResults, [BRes|Acc]);
recombine_reduce_results([_OsFun|RedSrcs], [OsR|OsResults], BuiltinResults, Acc) ->
recombine_reduce_results(RedSrcs, OsResults, BuiltinResults, [OsR|Acc]).
os_reduce(_Lang, [], _KVs) ->
{ok, []};
os_reduce(#proc{} = Proc, OsRedSrcs, KVs) ->
[true, Reductions] = proc_prompt(Proc, [<<"reduce">>, OsRedSrcs, KVs]),
{ok, Reductions};
os_reduce(Lang, OsRedSrcs, KVs) ->
Proc = get_os_process(Lang),
try os_reduce(Proc, OsRedSrcs, KVs) after ok = ret_os_process(Proc) end.
os_rereduce(#proc{} = Proc, OsRedSrcs, KVs) ->
[true, [Reduction]] = proc_prompt(Proc, [<<"rereduce">>, OsRedSrcs, KVs]),
Reduction;
os_rereduce(Lang, OsRedSrcs, KVs) ->
Proc = get_os_process(Lang),
try os_rereduce(Proc, OsRedSrcs, KVs) after ok = ret_os_process(Proc) end.
builtin_reduce(_Re, [], _KVs, Acc) ->
{ok, lists:reverse(Acc)};
builtin_reduce(Re, [<<"_sum",_/binary>>|BuiltinReds], KVs, Acc) ->
Sum = builtin_sum_rows(KVs),
builtin_reduce(Re, BuiltinReds, KVs, [Sum|Acc]);
builtin_reduce(reduce, [<<"_count",_/binary>>|BuiltinReds], KVs, Acc) ->
Count = length(KVs),
builtin_reduce(reduce, BuiltinReds, KVs, [Count|Acc]);
builtin_reduce(rereduce, [<<"_count",_/binary>>|BuiltinReds], KVs, Acc) ->
Count = builtin_sum_rows(KVs),
builtin_reduce(rereduce, BuiltinReds, KVs, [Count|Acc]);
builtin_reduce(Re, [<<"_stats",_/binary>>|BuiltinReds], KVs, Acc) ->
Stats = builtin_stats(Re, KVs),
builtin_reduce(Re, BuiltinReds, KVs, [Stats|Acc]).
builtin_sum_rows(KVs) ->
lists:foldl(fun
([_Key, Value], Acc) when is_number(Value) ->
Acc + Value;
(_Else, _Acc) ->
throw({invalid_value, <<"builtin _sum function requires map values to be numbers">>})
end, 0, KVs).
builtin_stats(reduce, [[_,First]|Rest]) when is_number(First) ->
Stats = lists:foldl(fun([_K,V], {S,C,Mi,Ma,Sq}) when is_number(V) ->
{S+V, C+1, erlang:min(Mi,V), erlang:max(Ma,V), Sq+(V*V)};
(_, _) ->
throw({invalid_value,
<<"builtin _stats function requires map values to be numbers">>})
end, {First,1,First,First,First*First}, Rest),
{Sum, Cnt, Min, Max, Sqr} = Stats,
{[{sum,Sum}, {count,Cnt}, {min,Min}, {max,Max}, {sumsqr,Sqr}]};
builtin_stats(rereduce, [[_,First]|Rest]) ->
{[{sum,Sum0}, {count,Cnt0}, {min,Min0}, {max,Max0}, {sumsqr,Sqr0}]} = First,
Stats = lists:foldl(fun([_K,Red], {S,C,Mi,Ma,Sq}) ->
{[{sum,Sum}, {count,Cnt}, {min,Min}, {max,Max}, {sumsqr,Sqr}]} = Red,
{Sum+S, Cnt+C, erlang:min(Min,Mi), erlang:max(Max,Ma), Sqr+Sq}
end, {Sum0,Cnt0,Min0,Max0,Sqr0}, Rest),
{Sum, Cnt, Min, Max, Sqr} = Stats,
{[{sum,Sum}, {count,Cnt}, {min,Min}, {max,Max}, {sumsqr,Sqr}]}.
% use the function stored in ddoc.validate_doc_update to test an update.
validate_doc_update(DDoc, EditDoc, DiskDoc, Ctx, SecObj) ->
JsonEditDoc = couch_doc:to_json_obj(EditDoc, [revs]),
JsonDiskDoc = json_doc(DiskDoc),
case ddoc_prompt(DDoc, [<<"validate_doc_update">>], [JsonEditDoc, JsonDiskDoc, Ctx, SecObj]) of
1 ->
ok;
{[{<<"forbidden">>, Message}]} ->
throw({forbidden, Message});
{[{<<"unauthorized">>, Message}]} ->
throw({unauthorized, Message})
end.
json_doc(nil) -> null;
json_doc(Doc) ->
couch_doc:to_json_obj(Doc, [revs]).
filter_docs(Req, Db, DDoc, FName, Docs) ->
JsonReq = case Req of
{json_req, JsonObj} ->
JsonObj;
#httpd{} = HttpReq ->
couch_httpd_external:json_req_obj(HttpReq, Db)
end,
JsonDocs = [couch_doc:to_json_obj(Doc, [revs]) || Doc <- Docs],
[true, Passes] = ddoc_prompt(DDoc, [<<"filters">>, FName], [JsonDocs, JsonReq]),
{ok, Passes}.
ddoc_proc_prompt({Proc, DDocId}, FunPath, Args) ->
proc_prompt(Proc, [<<"ddoc">>, DDocId, FunPath, Args]).
ddoc_prompt(DDoc, FunPath, Args) ->
with_ddoc_proc(DDoc, fun({Proc, DDocId}) ->
proc_prompt(Proc, [<<"ddoc">>, DDocId, FunPath, Args])
end).
with_ddoc_proc(#doc{id=DDocId,revs={Start, [DiskRev|_]}}=DDoc, Fun) ->
Rev = couch_doc:rev_to_str({Start, DiskRev}),
DDocKey = {DDocId, Rev},
Proc = get_ddoc_process(DDoc, DDocKey),
try Fun({Proc, DDocId})
after
ok = ret_os_process(Proc)
end.
proc_prompt(Proc, Args) ->
{Mod, Func} = Proc#proc.prompt_fun,
apply(Mod, Func, [Proc#proc.pid, Args]).
proc_stop(Proc) ->
{Mod, Func} = Proc#proc.stop_fun,
apply(Mod, Func, [Proc#proc.pid]).
proc_set_timeout(Proc, Timeout) ->
{Mod, Func} = Proc#proc.set_timeout_fun,
apply(Mod, Func, [Proc#proc.pid, Timeout]).
get_ddoc_process(#doc{} = DDoc, DDocKey) ->
% remove this case statement
case gen_server:call(couch_proc_manager, {get_proc, DDoc, DDocKey}) of
{ok, Proc, QueryConfig} ->
% process knows the ddoc
case (catch proc_prompt(Proc, [<<"reset">>, QueryConfig])) of
true ->
proc_set_timeout(Proc, list_to_integer(couch_config:get(
"couchdb", "os_process_timeout", "5000"))),
Proc;
_ ->
catch proc_stop(Proc),
get_ddoc_process(DDoc, DDocKey)
end;
Error ->
throw(Error)
end.
get_os_process(Lang) ->
case gen_server:call(couch_proc_manager, {get_proc, Lang}) of
{ok, Proc, QueryConfig} ->
case (catch proc_prompt(Proc, [<<"reset">>, QueryConfig])) of
true ->
proc_set_timeout(Proc, list_to_integer(couch_config:get(
"couchdb", "os_process_timeout", "5000"))),
Proc;
_ ->
catch proc_stop(Proc),
get_os_process(Lang)
end;
Error ->
throw(Error)
end.
ret_os_process(Proc) ->
true = gen_server:call(couch_proc_manager, {ret_proc, Proc}),
catch unlink(Proc#proc.pid),
ok.
|
