%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1997-2010. 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(ram_file).
%% Binary RAM file interface
%% Generic file contents operations
-export([open/2, close/1]).
-export([write/2, read/2, copy/3,
pread/2, pread/3, pwrite/2, pwrite/3,
position/2, truncate/1, datasync/1, sync/1]).
%% Specialized file operations
-export([get_size/1, get_file/1, set_file/2, get_file_close/1]).
-export([compress/1, uncompress/1, uuencode/1, uudecode/1, advise/4]).
-export([open_mode/1]). %% used by ftp-file
-export([ipread_s32bu_p32bu/3]).
%% Includes and defines
-define(RAM_FILE_DRV, "ram_file_drv").
-define(MAX_I32, (1 bsl 31)).
-define(G_I32(X), is_integer(X), X >= -?MAX_I32, X < ?MAX_I32).
-include("file.hrl").
%% --------------------------------------------------------------------------
%% These operation codes were once identical between efile_drv.c
%% and ram_file_drv.c, but now these drivers are not depeding on each other.
%% So, the codes could be changed to more logical values now, but why indeed?
%% Defined "file" functions
-define(RAM_FILE_OPEN, 1).
-define(RAM_FILE_READ, 2).
-define(RAM_FILE_LSEEK, 3).
-define(RAM_FILE_WRITE, 4).
-define(RAM_FILE_FSYNC, 9).
-define(RAM_FILE_TRUNCATE, 14).
-define(RAM_FILE_PREAD, 17).
-define(RAM_FILE_PWRITE, 18).
-define(RAM_FILE_FDATASYNC, 19).
%% Other operations
-define(RAM_FILE_GET, 30).
-define(RAM_FILE_SET, 31).
-define(RAM_FILE_GET_CLOSE, 32).
-define(RAM_FILE_COMPRESS, 33).
-define(RAM_FILE_UNCOMPRESS, 34).
-define(RAM_FILE_UUENCODE, 35).
-define(RAM_FILE_UUDECODE, 36).
-define(RAM_FILE_SIZE, 37).
-define(RAM_FILE_ADVISE, 38).
%% Open modes for RAM_FILE_OPEN
-define(RAM_FILE_MODE_READ, 1).
-define(RAM_FILE_MODE_WRITE, 2).
-define(RAM_FILE_MODE_READ_WRITE, 3).
%% Use this mask to get just the mode bits to be passed to the driver.
-define(RAM_FILE_MODE_MASK, 3).
%% Seek modes for RAM_FILE_LSEEK
-define(RAM_FILE_SEEK_SET, 0).
-define(RAM_FILE_SEEK_CUR, 1).
-define(RAM_FILE_SEEK_END, 2).
%% Return codes
-define(RAM_FILE_RESP_OK, 0).
-define(RAM_FILE_RESP_ERROR, 1).
-define(RAM_FILE_RESP_DATA, 2).
-define(RAM_FILE_RESP_NUMBER, 3).
-define(RAM_FILE_RESP_INFO, 4).
%% POSIX file advises
-define(POSIX_FADV_NORMAL, 0).
-define(POSIX_FADV_RANDOM, 1).
-define(POSIX_FADV_SEQUENTIAL, 2).
-define(POSIX_FADV_WILLNEED, 3).
-define(POSIX_FADV_DONTNEED, 4).
-define(POSIX_FADV_NOREUSE, 5).
%% --------------------------------------------------------------------------
%% Generic file contents operations.
%%
%% Supposed to be called by applications through module file.
open(Data, ModeList) when is_list(ModeList) ->
case open_mode(ModeList) of
{Mode,Opts} when is_integer(Mode) ->
case ll_open(Data, Mode, Opts) of
{ok,Port} ->
{ok,#file_descriptor{module=?MODULE, data=Port}};
Error ->
Error
end;
{error,_}=Error ->
Error
end;
%% Old obsolete mode specification
open(Data, Mode) ->
case mode_list(Mode) of
ModeList when is_list(ModeList) ->
open(Data, ModeList);
Error ->
Error
end.
close(#file_descriptor{module = ?MODULE, data = Port}) ->
ll_close(Port).
read(#file_descriptor{module = ?MODULE, data = Port}, Sz)
when is_integer(Sz), Sz >= 0 ->
if
?G_I32(Sz) ->
Cmd = <<?RAM_FILE_READ:8,Sz:32>>,
case call_port(Port, Cmd) of
{ok, {0, _Data}} when Sz =/= 0 ->
eof;
{ok, {_Sz, Data}} ->
{ok, Data};
{error, enomem} ->
%% Garbage collecting here might help if
%% the current processes has some old binaries left.
erlang:garbage_collect(),
case call_port(Port, Cmd) of
{ok, {0, _Data}} when Sz =/= 0 ->
eof;
{ok, {_Sz, Data}} ->
{ok, Data};
Error ->
Error
end;
Error ->
Error
end;
true ->
{error, einval}
end.
write(#file_descriptor{module = ?MODULE, data = Port}, Bytes) ->
case call_port(Port, [?RAM_FILE_WRITE | Bytes]) of
{ok, _Sz} ->
ok;
Error ->
Error
end.
copy(#file_descriptor{module = ?MODULE} = Source,
#file_descriptor{module = ?MODULE} = Dest,
Length)
when is_integer(Length), Length >= 0;
is_atom(Length) ->
%% XXX Should be moved down to the driver for optimization.
file:copy_opened(Source, Dest, Length).
datasync(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, <<?RAM_FILE_FDATASYNC>>).
sync(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, <<?RAM_FILE_FSYNC>>).
truncate(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, <<?RAM_FILE_TRUNCATE>>).
position(#file_descriptor{module = ?MODULE, data = Port}, Pos) ->
case lseek_position(Pos) of
{ok, Offs, Whence} when ?G_I32(Offs) ->
call_port(Port, <<?RAM_FILE_LSEEK:8,Offs:32,Whence:32>>);
{ok, _, _} ->
{error, einval};
Error ->
Error
end.
pread(#file_descriptor{module = ?MODULE, data = Port}, L) when is_list(L) ->
pread_1(Port, L, []).
pread_1(Port, [], Cs) ->
pread_2(Port, lists:reverse(Cs), []);
pread_1(Port, [{At, Sz} | T], Cs)
when is_integer(At), is_integer(Sz), Sz >= 0 ->
if
?G_I32(At), ?G_I32(Sz) ->
pread_1(Port, T, [{Sz,<<?RAM_FILE_PREAD:8,At:32,Sz:32>>}|Cs]);
true ->
{error, einval}
end;
pread_1(_, _, _243) ->
{error, badarg}.
pread_2(_Port, [], R) ->
{ok, lists:reverse(R)};
pread_2(Port, [{Sz,Command}|Commands], R) ->
case call_port(Port, Command) of
{ok, {0,_Data}} when Sz =/= 0 ->
pread_2(Port, Commands, [eof | R]);
{ok, {_Sz,Data}} ->
pread_2(Port, Commands, [Data | R]);
Error ->
Error
end.
pread(#file_descriptor{module = ?MODULE, data = Port}, At, Sz)
when is_integer(At), is_integer(Sz), Sz >= 0 ->
if
?G_I32(At), ?G_I32(Sz) ->
case call_port(Port, <<?RAM_FILE_PREAD:8,At:32,Sz:32>>) of
{ok, {0,_Data}} when Sz =/= 0 ->
eof;
{ok, {_Sz,Data}} ->
{ok, Data};
Error ->
Error
end;
true ->
{error, einval}
end;
pread(#file_descriptor{module = ?MODULE}, _, _) ->
{error, badarg}.
pwrite(#file_descriptor{module = ?MODULE, data = Port}, L) when is_list(L) ->
pwrite_1(Port, L, 0, []).
pwrite_1(Port, [], _, Cs) ->
pwrite_2(Port, lists:reverse(Cs), 0);
pwrite_1(Port, [{At, Bytes} | T], R, Cs) when is_integer(At) ->
if
?G_I32(At), is_binary(Bytes) ->
pwrite_1(Port, T, R+1,
[<<?RAM_FILE_PWRITE:8,At:32,Bytes/binary>> | Cs]);
?G_I32(At) ->
try erlang:iolist_to_binary(Bytes) of
Bin ->
pwrite_1(Port, T, R+1,
[<<?RAM_FILE_PWRITE:8,At:32,Bin/binary>> | Cs])
catch
error:Reason ->
{error, Reason}
end;
true ->
{error, {R, einval}}
end;
pwrite_1(_, _, _, _) ->
{error, badarg}.
pwrite_2(_Port, [], _R) ->
ok;
pwrite_2(Port, [Command|Commands], R) ->
case call_port(Port, Command) of
{ok, _Sz} ->
pwrite_2(Port, Commands, R+1);
{error, badarg} = Error ->
Error;
{error, Reason} ->
{error, {R, Reason}}
end.
pwrite(#file_descriptor{module = ?MODULE, data = Port}, At, Bytes)
when is_integer(At) ->
if
?G_I32(At) ->
case call_port(Port, [<<?RAM_FILE_PWRITE:8,At:32>>|Bytes]) of
{ok, _Sz} ->
ok;
Error ->
Error
end;
true ->
{error, einval}
end;
pwrite(#file_descriptor{module = ?MODULE}, _, _) ->
{error, badarg}.
ipread_s32bu_p32bu(#file_descriptor{module = ?MODULE} = Handle, Pos, MaxSz) ->
file:ipread_s32bu_p32bu_int(Handle, Pos, MaxSz).
%% --------------------------------------------------------------------------
%% Specialized ram_file API for functions not in file, unique to ram_file.
%%
get_file(#file_descriptor{module = ?MODULE, data = Port}) ->
case call_port(Port, [?RAM_FILE_GET]) of
{ok, {_Sz, Data}} ->
{ok, Data};
Error ->
Error
end;
get_file(#file_descriptor{}) ->
{error, enotsup}.
set_file(#file_descriptor{module = ?MODULE, data = Port}, Data) ->
call_port(Port, [?RAM_FILE_SET | Data]);
set_file(#file_descriptor{}, _) ->
{error, enotsup}.
get_file_close(#file_descriptor{module = ?MODULE, data = Port}) ->
case call_port(Port, [?RAM_FILE_GET_CLOSE]) of
{ok, {_Sz, Data}} ->
{ok, Data};
Error ->
Error
end;
get_file_close(#file_descriptor{}) ->
{error, enotsup}.
get_size(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, [?RAM_FILE_SIZE]);
get_size(#file_descriptor{}) ->
{error, enotsup}.
compress(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, [?RAM_FILE_COMPRESS]);
compress(#file_descriptor{}) ->
{error, enotsup}.
uncompress(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, [?RAM_FILE_UNCOMPRESS]);
uncompress(#file_descriptor{}) ->
{error, enotsup}.
uuencode(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, [?RAM_FILE_UUENCODE]);
uuencode(#file_descriptor{}) ->
{error, enotsup}.
uudecode(#file_descriptor{module = ?MODULE, data = Port}) ->
call_port(Port, [?RAM_FILE_UUDECODE]);
uudecode(#file_descriptor{}) ->
{error, enotsup}.
advise(#file_descriptor{module = ?MODULE, data = Port}, Offset,
Length, Advise) ->
Cmd0 = <<?RAM_FILE_ADVISE, Offset:64/signed, Length:64/signed>>,
case Advise of
normal ->
call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NORMAL:32/signed>>);
random ->
call_port(Port, <<Cmd0/binary, ?POSIX_FADV_RANDOM:32/signed>>);
sequential ->
call_port(Port, <<Cmd0/binary, ?POSIX_FADV_SEQUENTIAL:32/signed>>);
will_need ->
call_port(Port, <<Cmd0/binary, ?POSIX_FADV_WILLNEED:32/signed>>);
dont_need ->
call_port(Port, <<Cmd0/binary, ?POSIX_FADV_DONTNEED:32/signed>>);
no_reuse ->
call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NOREUSE:32/signed>>);
_ ->
{error, einval}
end;
advise(#file_descriptor{}, _Offset, _Length, _Advise) ->
{error, enotsup}.
%%%-----------------------------------------------------------------
%%% Functions to communicate with the driver
ll_open(Data, Mode, Opts) ->
try erlang:open_port({spawn, ?RAM_FILE_DRV}, Opts) of
Port ->
case call_port(Port, [<<?RAM_FILE_OPEN:8,Mode:32>>|Data]) of
{error, _} = Error ->
ll_close(Port),
Error;
{ok, _} ->
{ok, Port}
end
catch
error:Reason ->
{error, Reason}
end.
call_port(Port, Command) when is_port(Port), is_binary(Command) ->
try erlang:port_command(Port, Command) of
true ->
get_response(Port)
catch
error:badarg ->
{error, einval}; % Since Command is valid, Port must be dead
error:Reason ->
{error, Reason}
end;
call_port(Port, Command) ->
try erlang:iolist_to_binary(Command) of
Bin ->
call_port(Port, Bin)
catch
error:Reason ->
{error, Reason}
end.
get_response(Port) ->
receive
{Port, {data, [Response|Rest]}} ->
translate_response(Response, Rest);
{'EXIT', Port, _Reason} ->
{error, port_died}
end.
ll_close(Port) ->
try erlang:port_close(Port) catch error:_ -> ok end,
receive %% In case the caller is the owner and traps exits
{'EXIT', Port, _} ->
ok
after 0 ->
ok
end.
%%%-----------------------------------------------------------------
%%% Utility functions.
mode_list(read) ->
[read];
mode_list(write) ->
[write];
mode_list(read_write) ->
[read, write];
mode_list({binary, Mode}) when is_atom(Mode) ->
[binary | mode_list(Mode)];
mode_list({character, Mode}) when is_atom(Mode) ->
mode_list(Mode);
mode_list(_) ->
{error, badarg}.
%% Converts a list of mode atoms into an mode word for the driver.
%% Returns {Mode, Opts} wher Opts is a list of options for
%% erlang:open_port/2, or {error, einval} upon failure.
open_mode(List) when is_list(List) ->
case open_mode(List, {0, []}) of
{Mode, Opts} when Mode band
(?RAM_FILE_MODE_READ bor ?RAM_FILE_MODE_WRITE)
=:= 0 ->
{Mode bor ?RAM_FILE_MODE_READ, Opts};
Other ->
Other
end.
open_mode([ram|Rest], {Mode, Opts}) ->
open_mode(Rest, {Mode, Opts});
open_mode([read|Rest], {Mode, Opts}) ->
open_mode(Rest, {Mode bor ?RAM_FILE_MODE_READ, Opts});
open_mode([write|Rest], {Mode, Opts}) ->
open_mode(Rest, {Mode bor ?RAM_FILE_MODE_WRITE, Opts});
open_mode([binary|Rest], {Mode, Opts}) ->
open_mode(Rest, {Mode, [binary | Opts]});
open_mode([], {Mode, Opts}) ->
{Mode, Opts};
open_mode(_, _) ->
{error, badarg}.
%% Converts a position tuple {bof, X} | {cur, X} | {eof, X} into
%% {ok, Offset, OriginCode} for the driver.
%% Returns {error, einval} upon failure.
lseek_position(Pos) when is_integer(Pos) ->
lseek_position({bof, Pos});
lseek_position(bof) ->
lseek_position({bof, 0});
lseek_position(cur) ->
lseek_position({cur, 0});
lseek_position(eof) ->
lseek_position({eof, 0});
lseek_position({bof, Offset}) when is_integer(Offset) ->
{ok, Offset, ?RAM_FILE_SEEK_SET};
lseek_position({cur, Offset}) when is_integer(Offset) ->
{ok, Offset, ?RAM_FILE_SEEK_CUR};
lseek_position({eof, Offset}) when is_integer(Offset) ->
{ok, Offset, ?RAM_FILE_SEEK_END};
lseek_position(_) ->
{error, badarg}.
translate_response(?RAM_FILE_RESP_OK, []) ->
ok;
translate_response(?RAM_FILE_RESP_OK, Data) ->
{ok, Data};
translate_response(?RAM_FILE_RESP_ERROR, List) when is_list(List) ->
{error, list_to_atom(List)};
translate_response(?RAM_FILE_RESP_NUMBER, [X1, X2, X3, X4]) ->
{ok, i32(X1, X2, X3, X4)};
translate_response(?RAM_FILE_RESP_DATA, [X1, X2, X3, X4|Data]) ->
{ok, {i32(X1, X2, X3, X4), Data}};
translate_response(X, Data) ->
{error, {bad_response_from_port, X, Data}}.
i32(X1,X2,X3,X4) ->
(X1 bsl 24) bor (X2 bsl 16) bor (X3 bsl 8) bor X4.
