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Diffstat (limited to 'src/util.erl')
-rw-r--r-- | src/util.erl | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/src/util.erl b/src/util.erl new file mode 100644 index 0000000..48ebbb0 --- /dev/null +++ b/src/util.erl @@ -0,0 +1,57 @@ +%% +%% 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. |