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%%
%% Copyright (c) 2014 Kungliga Tekniska Högskolan
%% (KTH Royal Institute of Technology, Stockholm, Sweden).
%%
-module(util).
-export([tempfilename/1, fsync/1, exit_with_error/3,
check_error/3, write_tempfile_and_rename/3]).
-spec tempfilename(string()) -> string().
tempfilename(Base) ->
{MegaSecs, Secs, MicroSecs} = now(),
Filename = io_lib:format("~s-~s-~p.~p", [Base, os:getpid(),
MegaSecs * 1000000 + Secs, MicroSecs]),
Filename.
-spec fsync([string()]) -> ok.
fsync([]) ->
ok;
fsync([Name | Rest]) ->
case fsyncport:fsync(Name) of
ok ->
fsync(Rest);
{error, Error} ->
exit_with_error(fsync, Error, "Error in fsync")
end.
-spec exit_with_error(atom(), atom(), string()) -> no_return().
exit_with_error(Operation, Error, ErrorMessage) ->
io:format("~s(~w): ~w~n", [ErrorMessage, Operation, Error]),
exit({fileerror, Operation, Error, ErrorMessage}).
-spec check_error(any(), atom(), string()) -> ok.
check_error(ReturnValue, Operation, ErrorMessage) ->
case ReturnValue of
ok ->
ok;
{error, Error} ->
exit_with_error(Operation, Error, ErrorMessage)
end.
-spec write_tempfile_and_rename(string(), string(), binary()) -> ok.
write_tempfile_and_rename(Name, NurseryName, Content) ->
case file:open(NurseryName, [write, exclusive]) of
{ok, File} ->
ok = file:write(File, Content),
file:close(File),
check_error(file:rename(NurseryName, Name), rename,
"Error when renaming tempfile to final file");
{error, eexist} ->
%% Should not happen, file name should be unique
exit_with_error(writefile, eexist,
"File existed when creating tempfile");
{error, Error} ->
exit_with_error(writefile, Error,
"Error when creating tempfile")
end.
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