Merged mochiweb branch back into trunk.

git-svn-id: https://svn.apache.org/repos/asf/incubator/couchdb/trunk@648222 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 107 insertions, 0 deletions

diff --git a/src/mochiweb/reloader.erl b/src/mochiweb/reloader.erl
new file mode 100644
index 00000000..fcb27c1c
--- /dev/null
+++ b/src/mochiweb/reloader.erl
@@ -0,0 +1,107 @@
+%% @copyright 2007 Mochi Media, Inc.
+%% @author Matthew Dempsky <matthew@mochimedia.com>
+%%
+%% @doc Erlang module for automatically reloading modified modules
+%% during development.
+
+-module(reloader).
+-author("Matthew Dempsky <matthew@mochimedia.com>").
+
+-include_lib("kernel/include/file.hrl").
+
+-behaviour(gen_server).
+-export([start/0, start_link/0]).
+-export([stop/0]).
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
+
+-record(state, {last, tref}).
+
+%% External API
+
+%% @spec start() -> ServerRet
+%% @doc Start the reloader.
+start() ->
+    gen_server:start({local, ?MODULE}, ?MODULE, [], []).
+
+%% @spec start_link() -> ServerRet
+%% @doc Start the reloader.
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+%% @spec stop() -> ok
+%% @doc Stop the reloader.
+stop() ->
+    gen_server:call(?MODULE, stop).
+
+%% gen_server callbacks
+
+%% @spec init([]) -> {ok, State}
+%% @doc gen_server init, opens the server in an initial state.
+init([]) ->
+    {ok, TRef} = timer:send_interval(timer:seconds(1), doit),
+    {ok, #state{last = stamp(), tref = TRef}}.
+
+%% @spec handle_call(Args, From, State) -> tuple()
+%% @doc gen_server callback.
+handle_call(stop, _From, State) ->
+    {stop, shutdown, stopped, State};
+handle_call(_Req, _From, State) ->
+    {reply, {error, badrequest}, State}.
+
+%% @spec handle_cast(Cast, State) -> tuple()
+%% @doc gen_server callback.
+handle_cast(_Req, State) ->
+    {noreply, State}.
+
+%% @spec handle_info(Info, State) -> tuple()
+%% @doc gen_server callback.
+handle_info(doit, State) ->
+    Now = stamp(),
+    doit(State#state.last, Now),
+    {noreply, State#state{last = Now}};
+handle_info(_Info, State) ->
+    {noreply, State}.
+
+%% @spec terminate(Reason, State) -> ok
+%% @doc gen_server termination callback.
+terminate(_Reason, State) ->
+    {ok, cancel} = timer:cancel(State#state.tref),
+    ok.
+
+
+%% @spec code_change(_OldVsn, State, _Extra) -> State
+%% @doc gen_server code_change callback (trivial).
+code_change(_Vsn, State, _Extra) ->
+    {ok, State}.
+
+%% Internal API
+
+doit(From, To) ->
+    [case file:read_file_info(Filename) of
+         {ok, FileInfo} when FileInfo#file_info.mtime >= From,
+                             FileInfo#file_info.mtime < To ->
+             io:format("Reloading ~p ...", [Module]),
+             code:purge(Module),
+             case code:load_file(Module) of
+                 {module, Module} ->
+                     io:format(" ok.~n"),
+                     reload;
+                 {error, Reason} ->
+                     io:format(" ~p.~n", [Reason]),
+                     error
+             end;
+         {ok, _} ->
+             unmodified;
+         {error, enoent} ->
+             %% The Erlang compiler deletes existing .beam files if
+             %% recompiling fails.  Maybe it's worth spitting out a
+             %% warning here, but I'd want to limit it to just once.
+             gone;
+         {error, Reason} ->
+             io:format("Error reading ~s's file info: ~p~n",
+                       [Filename, Reason]),
+             error
+     end || {Module, Filename} <- code:all_loaded(), is_list(Filename)].
+
+stamp() ->
+    erlang:localtime().