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diff --git a/lib/stdlib/src/log_mf_h.erl b/lib/stdlib/src/log_mf_h.erl
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+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 1996-2009. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+-module(log_mf_h).
+
+-behaviour(gen_event).
+
+-export([init/3, init/4]).
+
+-export([init/1, handle_event/2, handle_info/2, terminate/2]).
+-export([handle_call/2, code_change/3]).
+
+%%-----------------------------------------------------------------
+
+-type dir() :: file:filename().
+-type b() :: non_neg_integer().
+-type f() :: 1..255.
+-type pred() :: fun((term()) -> boolean()).
+
+%%-----------------------------------------------------------------
+
+-record(state, {dir :: dir(),
+ maxB :: b(),
+ maxF :: f(),
+ curB :: b(),
+ curF :: f(),
+ cur_fd :: file:fd(),
+ index = [], %% Seems unused - take out??
+ pred :: pred()}).
+
+%%%-----------------------------------------------------------------
+%%% This module implements an event handler that writes events
+%%% to multiple files (configurable).
+%%%-----------------------------------------------------------------
+%% Func: init/3, init/4
+%% Args: Dir = string()
+%% MaxB = integer()
+%% MaxF = byte()
+%% Pred = fun(Event) -> boolean()
+%% Purpose: An event handler. Writes binary events
+%% to files in the directory Dir. Each file is called
+%% 1, 2, 3, ..., MaxF. Writes MaxB bytes on each file.
+%% Creates a file called 'index' in the Dir.
+%% This file contains the last written FileName.
+%% On startup, this file is read, and the next available
+%% filename is used as first logfile.
+%% Each event is filtered with the predicate function Pred.
+%% Reports can be browsed with Report Browser Tool (rb).
+%% Returns: Args = term()
+%% The Args term should be used in a call to
+%% gen_event:add_handler(EventMgr, log_mf_h, Args)
+%% EventMgr = pid() | atom().
+%%-----------------------------------------------------------------
+
+-spec init(dir(), b(), f()) -> {dir(), b(), f(), pred()}.
+
+init(Dir, MaxB, MaxF) -> init(Dir, MaxB, MaxF, fun(_) -> true end).
+
+-spec init(dir(), b(), f(), pred()) -> {dir(), b(), f(), pred()}.
+
+init(Dir, MaxB, MaxF, Pred) -> {Dir, MaxB, MaxF, Pred}.
+
+%%-----------------------------------------------------------------
+%% Call-back functions from gen_event
+%%-----------------------------------------------------------------
+
+-spec init({dir(), b(), f(), pred()}) -> {'ok', #state{}} | {'error', term()}.
+
+init({Dir, MaxB, MaxF, Pred}) when is_integer(MaxF), MaxF > 0, MaxF < 256 ->
+ First =
+ case read_index_file(Dir) of
+ {ok, LastWritten} -> inc(LastWritten, MaxF);
+ _ -> 1
+ end,
+ case catch file_open(Dir, First) of
+ {ok, Fd} ->
+ {ok, #state{dir = Dir, maxB = MaxB, maxF = MaxF, pred = Pred,
+ curF = First, cur_fd = Fd, curB = 0}};
+ Error -> Error
+ end.
+
+%%-----------------------------------------------------------------
+%% The handle_event/2 function may crash! In this case, this
+%% handler is removed by gen_event from the event handlers.
+%% Fails: 'file_open' if file:open failed for a log file.
+%% 'write_index_file' if file:write_file failed for the
+%% index file.
+%% {file_exit, Reason} if the current Fd crashes.
+%%-----------------------------------------------------------------
+
+-spec handle_event(term(), #state{}) -> {'ok', #state{}}.
+
+handle_event(Event, State) ->
+ #state{curB = CurB, maxB = MaxB, curF = CurF, maxF = MaxF,
+ dir = Dir, cur_fd = CurFd, pred = Pred} = State,
+ case catch Pred(Event) of
+ true ->
+ Bin = term_to_binary(tag_event(Event)),
+ Size = byte_size(Bin),
+ NewState =
+ if
+ CurB + Size < MaxB -> State;
+ true ->
+ ok = file:close(CurFd),
+ NewF = inc(CurF, MaxF),
+ {ok, NewFd} = file_open(Dir, NewF),
+ State#state{cur_fd = NewFd, curF = NewF, curB = 0}
+ end,
+ [Hi,Lo] = put_int16(Size),
+ file:write(NewState#state.cur_fd, [Hi, Lo, Bin]),
+ {ok, NewState#state{curB = NewState#state.curB + Size + 2}};
+ _ ->
+ {ok, State}
+ end.
+
+-spec handle_info(term(), #state{}) -> {'ok', #state{}}.
+
+handle_info({emulator, GL, Chars}, State) ->
+ handle_event({emulator, GL, Chars}, State);
+handle_info(_, State) ->
+ {ok, State}.
+
+-spec terminate(term(), #state{}) -> #state{}.
+
+terminate(_, State) ->
+ ok = file:close(State#state.cur_fd),
+ State.
+
+-spec handle_call('null', #state{}) -> {'ok', 'null', #state{}}.
+
+handle_call(null, State) ->
+ {ok, null, State}.
+
+-spec code_change(term(), #state{}, term()) -> {'ok', #state{}}.
+
+code_change(_OldVsn, State, _Extra) ->
+ {ok, State}.
+
+%%-----------------------------------------------------------------
+%% Misc local functions
+%%-----------------------------------------------------------------
+
+file_open(Dir, FileNo) ->
+ case file:open(Dir ++ [$/ | integer_to_list(FileNo)], [raw, write]) of
+ {ok, Fd} ->
+ write_index_file(Dir, FileNo),
+ {ok, Fd};
+ _ ->
+ exit({file, open})
+ end.
+
+put_int16(I) ->
+ [((I band 16#ff00) bsr 8),I band 16#ff].
+
+tag_event(Event) ->
+ {erlang:localtime(), Event}.
+
+read_index_file(Dir) ->
+ case file:open(Dir ++ "/index", [raw, read]) of
+ {ok, Fd} ->
+ Res = case catch file:read(Fd, 1) of
+ {ok, [Index]} -> {ok, Index};
+ _ -> error
+ end,
+ ok = file:close(Fd),
+ Res;
+ _ -> error
+ end.
+
+%%-----------------------------------------------------------------
+%% Write the index file. This file contains one binary with
+%% the last used filename (an integer).
+%%-----------------------------------------------------------------
+
+write_index_file(Dir, Index) ->
+ case file:open(Dir ++ "/index", [raw, write]) of
+ {ok, Fd} ->
+ file:write(Fd, [Index]),
+ ok = file:close(Fd);
+ _ -> exit(open_index_file)
+ end.
+
+inc(N, Max) ->
+ if
+ N < Max -> N + 1;
+ true -> 1
+ end.
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