add missing files

git-svn-id: https://svn.apache.org/repos/asf/incubator/couchdb/trunk@687339 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 392 insertions, 0 deletions

diff --git a/src/couchdb/couch_config.erl b/src/couchdb/couch_config.erl
new file mode 100644
index 00000000..07d47dff
--- /dev/null
+++ b/src/couchdb/couch_config.erl
@@ -0,0 +1,195 @@
+% 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.
+
+%% @doc 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).
+-include("couch_db.hrl").
+
+-behaviour(gen_server).
+-export([start_link/1, init/1,
+    handle_call/3, handle_cast/2, handle_info/2, 
+    terminate/2, code_change/3]).
+-export([store/2, register/1, register/2, 
+    get/1, get/2,
+    lookup_match/1, lookup_match/2,
+    all/0, unset/1, load_ini_file/1]).
+    
+-record(config,
+    {notify_funs=[],
+    writeback_filename=""
+    }).
+
+%% Public API %%
+
+%% @type etstable() = integer().
+
+start_link(IniFiles) -> gen_server:start_link({local, ?MODULE}, ?MODULE, IniFiles, []).  
+
+%% @spec store(Key::any(), Value::any()) -> {ok, Tab::etsatable()}
+%% @doc Public API function that triggers storage of a Key/Value pair into the
+%%      local ets table and writes it to the storage ini file.
+store(Key, Value) -> gen_server:call(?MODULE, {store, [{Key, Value}]}).
+
+%% @spec get(Key::any()) -> Value::any() | undefined
+%% @doc Returns the value that is stored under key::any() or undefined::atom() if no
+%%      such Key exists.
+get(Key) ->
+    ?MODULE:get(Key, undefined).
+
+%% @spec get(Key::any(), Default::any()) -> Value::any() | Default
+%% @doc Returns the value that is stored under key::any() or Default::any() if
+%%      no such Key exists.
+get(Key, Default) ->
+    fix_lookup_result(ets:lookup(?MODULE, Key), Default).
+
+%% @spec lookup_match(Key::any()) -> Value::any() | undefined:atom()
+%% @doc Lets you look for a Key's Value specifying a pattern that gets passed 
+%%      to ets::match(). Returns undefined::atom() if no Key is found.
+lookup_match(Key) -> gen_server:call(?MODULE, {lookup_match, Key}).
+
+%% @spec lookup_match(Key::any(), Default::any()) -> Value::any() | Default
+%% @doc Lets you look for a Key's Value specifying a pattern that gets passed 
+%%      to ets::match(). Returns Default::any() if no Key is found
+lookup_match(Key, Default) -> gen_server:call(?MODULE, {lookup_match, Key, Default}).
+
+all() -> gen_server:call(?MODULE, all).
+
+register(Fun) -> gen_server:call(?MODULE, {register, Fun, self()}).
+
+
+register(Fun, Pid) -> gen_server:call(?MODULE, {register, Fun, Pid}).
+
+%% @spec unset(Key::any) -> ok
+%% @doc Public API call to remove the configuration entry from the internal 
+%%      ets table. This change is _not_ written to the storage ini file.
+unset(Key) -> gen_server:call(?MODULE, {unset, Key}).
+
+%% Private API %%
+
+%% @spec init(List::list([])) -> {ok, Tab::etsatable()}
+%% @doc Creates a new ets table of the type "set".
+init(IniFiles) ->
+    ets:new(?MODULE, [named_table, set, protected]),
+    [ok = load_ini_file(IniFile) || IniFile <- IniFiles],
+    {ok, #config{writeback_filename=lists:last(IniFiles)}}.
+
+%% @doc see store/2
+handle_call({store, KVs}, _From, Config) ->
+    [ok = insert_and_commit(Config, KV) || KV <- KVs],
+    {reply, ok, Config};
+
+
+%% @doc See init_value/2
+handle_call({init_value, Key, Value}, _From, Config) ->
+    Reply = ets:insert(?MODULE, {Key, Value}),
+    {reply, Reply, Config};
+
+%% @doc See unset/1
+handle_call({unset, Key}, _From, Config) ->
+    ets:delete(?MODULE, Key),
+    {reply, ok, Config};
+
+
+%% @doc See lookup_match/2
+handle_call({lookup_match, Key, Default}, _From, Config) ->
+    {reply, fix_lookup_result(ets:match(?MODULE, Key), Default), Config};
+
+handle_call(all, _From, Config) ->
+    {reply, lists:sort(ets:tab2list(?MODULE)), Config};
+
+%% @doc See register/2
+handle_call({register, Fun, Pid}, _From, #config{notify_funs=PidFuns}=Config) ->
+    erlang:monitor(process, Pid),
+    {reply, ok, Config#config{notify_funs=[{Pid, Fun}|PidFuns]}}.
+    
+
+fix_lookup_result([{_Key, Value}], _Default) ->
+    Value;
+fix_lookup_result([], Default) ->
+    Default;
+fix_lookup_result(Values, _Default) ->
+    [list_to_tuple(Value) || Value <- Values].
+
+%% @spec insert_and_commit(Tab::etstable(), Config::any()) -> ok
+%% @doc Inserts a Key/Value pair into the ets table, writes it to the storage 
+%%      ini file and calls all registered callback functions for Key.
+insert_and_commit(Config, KV) ->
+    true = ets:insert(?MODULE, KV),
+    % notify funs
+    %[catch Fun(KV) || {_Pid, Fun} <- Config#config.notify_funs],
+    couch_config_writer:save_to_file(KV, Config#config.writeback_filename).
+
+%% @spec load_ini_file(IniFile::filename()) -> ok
+%% @doc Parses an ini file and stores Key/Value Pairs into the ets table.
+load_ini_file(IniFile) ->
+    IniFilename = couch_util:abs_pathname(IniFile),
+    IniBin =
+    case file:read_file(IniFilename) of
+        {ok, IniBin0} ->
+           IniBin0;
+        {error, enoent} ->
+           Msg = io_lib:format("Couldn't find server configuration file ~s.", [IniFilename]),
+           io:format("~s~n", [Msg]),
+           throw({startup_error, Msg})
+    end,
+    
+    {ok, Lines} = regexp:split(binary_to_list(IniBin), "\r\n|\n|\r|\032"),
+    {_, ParsedIniValues} =
+    lists:foldl(fun(Line, {AccSectionName, AccValues}) ->
+            case string:strip(Line) of
+            "[" ++ Rest ->
+                case regexp:split(Rest, "\\]") of
+                {ok, [NewSectionName, ""]} ->
+                    {NewSectionName, AccValues};
+                _Else -> % end bracket not at end, ignore this line
+                    {AccSectionName, AccValues}
+                end;
+            ";" ++ _Comment ->
+                {AccSectionName, AccValues};
+            Line2 ->
+                case regexp:split(Line2, "=") of
+                {ok, [_SingleElement]} -> % no "=" found, ignore this line
+                    {AccSectionName, AccValues};
+                {ok, [""|_LineValues]} -> % line begins with "=", ignore
+                    {AccSectionName, AccValues};
+                {ok, [ValueName|LineValues]} -> % yeehaw, got a line!
+                    RemainingLine = couch_util:implode(LineValues, "="),
+                    {ok, [LineValue | _Rest]} = regexp:split(RemainingLine, " ;|\t;"), % removes comments
+                    {AccSectionName, [{{AccSectionName, ValueName}, LineValue} | AccValues]}
+                end
+            end
+        end, {"", []}, Lines),
+        
+        [ets:insert(?MODULE, {Key, Value}) || {Key, Value} <- ParsedIniValues],
+    ok.
+
+% Unused gen_server behaviour API functions that we need to declare.
+
+%% @doc Unused
+handle_cast(foo, 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}}.
+
+%% @doc Unused
+terminate(_Reason, _State) -> ok.
+
+%% @doc Unused
+code_change(_OldVersion, State, _Extra) -> {ok, State}.
\ No newline at end of file
diff --git a/src/couchdb/couch_config_writer.erl b/src/couchdb/couch_config_writer.erl
new file mode 100644
index 00000000..6e93c131
--- /dev/null
+++ b/src/couchdb/couch_config_writer.erl
@@ -0,0 +1,147 @@
+% 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.
+
+%% @doc Saves a Key/Value pair to a ini file. The Key consists of a Module
+%%      and Variable combination. If that combination is found in the ini file
+%%      the new value replaces the old value. If only the Module is found the
+%%      Variable and value combination is appended to the Module. If the Module
+%%      does not yet exist in the ini file, it is added and the Variable/Value
+%%      pair is appended.
+%% @see couch_config
+
+-module(couch_config_writer).
+-include("couch_db.hrl").
+
+-export([save_to_file/2]).
+
+%% @spec save_to_file(
+%%           Config::{{Module::string(), Variable::string()}, Value::string()}, 
+%%           File::filename()) -> ok
+%% @doc Saves a Module/Key/Value triple to the ini file File::filename()
+save_to_file({{Module, Variable}, Value}, File) ->
+    
+    ?LOG_DEBUG("saving to file '~s', Congif: '~p'", [File, {{Module, Variable}, Value}]),
+    
+    % open file and create a list of lines
+    {ok, Stream} = file:read_file(File),
+    OldFileContents = binary_to_list(Stream),
+    {ok, Lines} = regexp:split(OldFileContents, "\r\n|\n|\r|\032"),
+    
+    % prepare input variables
+    ModuleName = "[" ++ Module ++ "]",
+    VariableList = Variable,
+    
+    % produce the contents for the config file
+    NewFileContents = 
+    case NewFileContents2 = save_loop({{ModuleName, VariableList}, Value}, Lines, "", "", []) of
+        % we didn't change anything, that means we couldn't find a matching
+        % [ini section] in which case we just append a new one.
+        OldFileContents ->
+            append_new_ini_section({{ModuleName, VariableList}, Value}, OldFileContents);
+        _ ->
+            NewFileContents2
+    end,
+    
+    % do the save, close the config file and get out
+    save_file(File, NewFileContents),
+    file:close(Stream),
+    ok.
+
+%% @doc Iterates over the lines of an ini file and replaces or adds a new
+%%      configuration directive.
+save_loop({{Module, Variable}, Value}, [Line|Rest], OldCurrentModule, Contents, DoneVariables) ->
+
+    % if we find a new [ini section] (Module), save that for reference
+    NewCurrentModule = parse_module(Line, OldCurrentModule),
+
+    % if the current Module is the one we want to change, try to match
+    % each line with the Variable
+    NewContents = case Module of
+        NewCurrentModule ->
+            % see if the current line matches the variable we want to substitute
+            case parse_variable(Line, Variable, Value) of
+                % nope, return original line
+                nomatch ->
+                    DoneVariables2 = DoneVariables,
+                    Line;
+                % got em! return new line
+                NewLine ->
+                    DoneVariables2 = [Variable|DoneVariables],
+                    NewLine
+            end;
+        % if the variable we want to change couldn't be replaced, we append it
+        % in the proper module section
+        OldCurrentModule ->
+            case lists:member(Variable, DoneVariables) of
+                false ->
+                    DoneVariables2 = [Variable|DoneVariables],
+                    Variable ++ "=" ++ Value ++ "\n" ++ Line;
+                true ->
+                    DoneVariables2 = DoneVariables,
+                    Line
+            end;
+        % otherwise we just print out the original line
+        _ ->
+            DoneVariables2 = DoneVariables,
+            Line
+        end,
+    % clumsy way to only append a newline character
+    % if the line is not empty. We need this to not
+    % avoid haveing a newline inserted at the top
+    % of the target file each time we save it.
+    Contents2 = case Contents of "" -> ""; _ -> Contents ++ "\n" end,
+
+    % go to next line
+    save_loop({{Module, Variable}, Value}, Rest, NewCurrentModule, Contents2 ++ NewContents, DoneVariables2);
+    
+save_loop(_Config, [], _OldModule, NewFileContents, _DoneVariable) ->
+    % we're out of new lines, just return the new file's contents
+    NewFileContents.
+
+append_new_ini_section({{ModuleName, Variable}, Value}, OldFileContents) ->
+    OldFileContents ++ "\n\n" ++ ModuleName ++ "\n" ++  Variable ++ "=" ++ Value ++ "\n".
+
+%% @spec parse_module(Lins::string(), OldModule::string()) -> string()
+%% @doc Tries to match a line against a pattern specifying a ini module or 
+%%      section ("[Module]"). Returns OldModule if no match is found.
+parse_module(Line, OldModule) ->
+    case regexp:match(Line, "^\\[([a-zA-Z0-9_-]*)\\]$") of
+        nomatch ->
+            OldModule;
+        {error, Error} ->
+            io:format("ini file regex error module: '~s'~n", [Error]),
+            OldModule;
+        {match, Start, Length} ->
+            string:substr(Line, Start, Length)
+    end.
+
+%% @spec parse_variable(Line::string(), Variable::string(), Value::string()) ->
+%%         string() | nomatch
+%% @doc Tries to match a variable assignment in Line. Returns nomatch if the
+%%      Variable is not found. Returns a new line composed of the Variable and
+%%      Value otherwise.
+parse_variable(Line, Variable, Value) ->
+    case regexp:match(Line, "^" ++ Variable ++ "=") of
+        nomatch ->
+            nomatch;
+        {error, Error}->
+            io:format("ini file regex error variable: '~s'~n", [Error]),
+            nomatch;
+        {match, _Start, _Length} ->
+            Variable ++ "=" ++ Value
+    end.
+
+%% @spec save_file(File::filename(), Contents::string()) -> 
+%%           ok | {error, Reason::string()}
+%% @doc Writes Contents to File
+save_file(File, Contents) ->
+    file:write_file(File, list_to_binary(Contents)).
\ No newline at end of file
diff --git a/src/couchdb/couch_db_update_notifier_sup.erl b/src/couchdb/couch_db_update_notifier_sup.erl
new file mode 100644
index 00000000..8902498d
--- /dev/null
+++ b/src/couchdb/couch_db_update_notifier_sup.erl
@@ -0,0 +1,50 @@
+% 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.
+
+%
+% This causes an OS process to spawned and it is notified every time a database
+% is updated.
+%
+% The notifications are in the form of a the database name sent as a line of
+% text to the OS processes stdout.
+%
+
+-module(couch_db_update_notifier_sup).
+
+-behaviour(supervisor).
+
+-export([start_link/0,init/1]).
+
+start_link() ->
+    supervisor:start_link({local, couch_db_update_notifier_sup},
+        couch_db_update_notifier_sup, []).
+
+init([]) ->
+    Self = self(),
+    ok = couch_config:register(
+        fun({"Update Notification", _}) ->
+            exit(Self, reload_config)
+        end),
+    
+    UpdateNotifierExes = couch_config:lookup_match(
+            {{"Update Notification", '$1'}, '$2'}, []),
+
+    {ok,
+        {{one_for_one, 10, 3600}, 
+            lists:map(fun({Name, UpdateNotifierExe}) ->
+                {Name,
+                {couch_db_update_notifier, start_link, [UpdateNotifierExe]},
+                    permanent,
+                    1000,
+                    supervisor,
+                    [couch_db_update_notifier]}
+                end, UpdateNotifierExes)}}.
\ No newline at end of file