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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.
% Reads CouchDB's ini file and gets queried for configuration parameters.
% This module is initialized with a list of ini files that it consecutively
% reads Key/Value pairs from and saves them in an ets table. If more an one
% ini file is specified, the last one is used to write changes that are made
% with store/2 back to that ini file.
-module(couch_config).
-behaviour(gen_server).
-include("couch_db.hrl").
-export([start_link/1, stop/0]).
-export([all/0, get/1, get/2, get/3, set/3, set/4, delete/2, delete/3]).
-export([register/1, register/2]).
-export([parse_ini_file/1]).
-export([init/1, terminate/2, code_change/3]).
-export([handle_call/3, handle_cast/2, handle_info/2]).
-record(config, {
notify_funs=[],
write_filename=undefined
}).
start_link(IniFiles) ->
gen_server:start_link({local, ?MODULE}, ?MODULE, IniFiles, []).
stop() ->
gen_server:cast(?MODULE, stop).
all() ->
lists:sort(gen_server:call(?MODULE, all)).
get(Section) when is_binary(Section) ->
?MODULE:get(?b2l(Section));
get(Section) ->
Matches = ets:match(?MODULE, {{Section, '$1'}, '$2'}),
[{Key, Value} || [Key, Value] <- Matches].
get(Section, Key) ->
?MODULE:get(Section, Key, undefined).
get(Section, Key, Default) when is_binary(Section) and is_binary(Key) ->
?MODULE:get(?b2l(Section), ?b2l(Key), Default);
get(Section, Key, Default) ->
case ets:lookup(?MODULE, {Section, Key}) of
[] -> Default;
[{_, Match}] -> Match
end.
set(Section, Key, Value) ->
?MODULE:set(Section, Key, Value, true).
set(Section, Key, Value, Persist) when is_binary(Section) and is_binary(Key) ->
?MODULE:set(?b2l(Section), ?b2l(Key), Value, Persist);
set(Section, Key, Value, Persist) ->
gen_server:call(?MODULE, {set, Section, Key, Value, Persist}).
delete(Section, Key) when is_binary(Section) and is_binary(Key) ->
delete(?b2l(Section), ?b2l(Key));
delete(Section, Key) ->
delete(Section, Key, true).
delete(Section, Key, Persist) when is_binary(Section) and is_binary(Key) ->
delete(?b2l(Section), ?b2l(Key), Persist);
delete(Section, Key, Persist) ->
gen_server:call(?MODULE, {delete, Section, Key, Persist}).
register(Fun) ->
?MODULE:register(Fun, self()).
register(Fun, Pid) ->
gen_server:call(?MODULE, {register, Fun, Pid}).
init(IniFiles) ->
ets:new(?MODULE, [named_table, set, protected]),
lists:map(fun(IniFile) ->
{ok, ParsedIniValues} = parse_ini_file(IniFile),
ets:insert(?MODULE, ParsedIniValues)
end, IniFiles),
WriteFile = case IniFiles of
[_|_] -> lists:last(IniFiles);
_ -> undefined
end,
{ok, #config{write_filename=WriteFile}}.
terminate(_Reason, _State) ->
ok.
handle_call(all, _From, Config) ->
Resp = lists:sort((ets:tab2list(?MODULE))),
{reply, Resp, Config};
handle_call({set, Sec, Key, Val, Persist}, _From, Config) ->
true = ets:insert(?MODULE, {{Sec, Key}, Val}),
case {Persist, Config#config.write_filename} of
{true, undefined} ->
ok;
{true, FileName} ->
couch_config_writer:save_to_file({{Sec, Key}, Val}, FileName);
_ ->
ok
end,
[catch F(Sec, Key, Val, Persist) || {_Pid, F} <- Config#config.notify_funs],
{reply, ok, Config};
handle_call({delete, Sec, Key, Persist}, _From, Config) ->
true = ets:delete(?MODULE, {Sec,Key}),
case {Persist, Config#config.write_filename} of
{true, undefined} ->
ok;
{true, FileName} ->
couch_config_writer:save_to_file({{Sec, Key}, ""}, FileName);
_ ->
ok
end,
[catch F(Sec, Key, deleted, Persist) || {_Pid, F} <- Config#config.notify_funs],
{reply, ok, Config};
handle_call({register, Fun, Pid}, _From, #config{notify_funs=PidFuns}=Config) ->
erlang:monitor(process, Pid),
% convert 1 and 2 arity to 3 arity
Fun2 =
case Fun of
_ when is_function(Fun, 1) ->
fun(Section, _Key, _Value, _Persist) -> Fun(Section) end;
_ when is_function(Fun, 2) ->
fun(Section, Key, _Value, _Persist) -> Fun(Section, Key) end;
_ when is_function(Fun, 3) ->
fun(Section, Key, Value, _Persist) -> Fun(Section, Key, Value) end;
_ when is_function(Fun, 4) ->
Fun
end,
{reply, ok, Config#config{notify_funs=[{Pid, Fun2} | PidFuns]}}.
handle_cast(stop, State) ->
{stop, normal, State};
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info({'DOWN', _, _, DownPid, _}, #config{notify_funs=PidFuns}=Config) ->
% remove any funs registered by the downed process
FilteredPidFuns = [{Pid,Fun} || {Pid,Fun} <- PidFuns, Pid /= DownPid],
{noreply, Config#config{notify_funs=FilteredPidFuns}}.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
parse_ini_file(IniFile) ->
IniFilename = couch_util:abs_pathname(IniFile),
IniBin =
case file:read_file(IniFilename) of
{ok, IniBin0} ->
IniBin0;
{error, enoent} ->
Fmt = "Couldn't find server configuration file ~s.",
Msg = ?l2b(io_lib:format(Fmt, [IniFilename])),
?LOG_ERROR("~s~n", [Msg]),
throw({startup_error, Msg})
end,
Lines = re:split(IniBin, "\r\n|\n|\r|\032", [{return, list}]),
{_, ParsedIniValues} =
lists:foldl(fun(Line, {AccSectionName, AccValues}) ->
case string:strip(Line) of
"[" ++ Rest ->
case re:split(Rest, "\\]", [{return, list}]) of
[NewSectionName, ""] ->
{NewSectionName, AccValues};
_Else -> % end bracket not at end, ignore this line
{AccSectionName, AccValues}
end;
";" ++ _Comment ->
{AccSectionName, AccValues};
Line2 ->
case re:split(Line2, "\s?=\s?", [{return, list}]) of
[_SingleElement] -> % no "=" found, ignore this line
{AccSectionName, AccValues};
[""|_LineValues] -> % line begins with "=", ignore
{AccSectionName, AccValues};
[ValueName|LineValues] -> % yeehaw, got a line!
RemainingLine = couch_util:implode(LineValues, "="),
% removes comments
case re:split(RemainingLine, " ;|\t;", [{return, list}]) of
[[]] ->
% empty line means delete this key
ets:delete(?MODULE, {AccSectionName, ValueName}),
{AccSectionName, AccValues};
[LineValue | _Rest] ->
{AccSectionName,
[{{AccSectionName, ValueName}, LineValue} | AccValues]}
end
end
end
end, {"", []}, Lines),
{ok, ParsedIniValues}.
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