procket_mktmp.erl

%% Copyright (c) 2010-2011, Michael Santos <michael.santos@gmail.com>
%% All rights reserved.
%%
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%% modification, are permitted provided that the following conditions
%% are met:
%%
%% Redistributions of source code must retain the above copyright
%% notice, this list of conditions and the following disclaimer.
%%
%% Redistributions in binary form must reproduce the above copyright
%% notice, this list of conditions and the following disclaimer in the
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%% without specific prior written permission.
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%% "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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%% Atomically create a temporary file.
%%
%% This module just creates a directory, put whatever temp files
%% you need inside the directory.
%%
-module(procket_mktmp).

-export([dirname/0,name/1,template/2,make_dir/1,close/1]).

-include_lib("kernel/include/file.hrl").

-define(TEMPLATE, "erlang-XXXXXXXXXXXX").
-define(S_IRWXU, 8#00400 bor 8#00200 bor 8#00100).
-define(ALPHANUM, "0123456789"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "abcdefghijklmnopqrstuvwxyz").

dirname() ->
    TMP = case os:getenv("TMPDIR") of
        false -> "/tmp";
        Dir -> Dir
    end,
    name(TMP ++ "/" ++ ?TEMPLATE).

name(Template) ->
    template(Template, ?ALPHANUM).

template(Name, Chars) ->
    crypto:start(),
    template(lists:reverse(Name), [], Chars).
template([$X|Rest], Acc, Chars) ->
    template(Rest,
        [lists:nth(crypto:rand_uniform(1, length(Chars)+1), Chars)|Acc],
        Chars);
template(Name, Rand, _) when length(Rand) >= 6 ->
    lists:reverse(Name) ++ Rand.

make_dir(Path) ->
    case file:make_dir(Path) of
        ok ->
            file:write_file_info(Path, #file_info{mode = ?S_IRWXU});
        Error ->
            Error
    end.

close(Path) ->
    file:del_dir(Path).