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