! Factor

USING: alien.strings fry io.encodings.utf16 kernel
splitting windows windows.kernel32 ;
IN: environment.winnt

M: winnt os-env ( key -- value )
    MAX_UNICODE_PATH "TCHAR" <c-array>
    [ dup length GetEnvironmentVariable ] keep over 0 = [
        2drop f
    ] [
        nip utf16n alien>string
    ] if ;

M: winnt set-os-env ( value key -- )
    swap SetEnvironmentVariable win32-error=0/f ;

M: winnt unset-os-env ( key -- )
    f SetEnvironmentVariable 0 = [
        GetLastError ERROR_ENVVAR_NOT_FOUND =
        [ win32-error ] unless
    ] when ;

M: winnt (os-envs) ( -- seq )
    GetEnvironmentStrings [
        <memory-stream> [
            utf16n decode-input
            [ "\0" read-until drop dup empty? not ]
            [ ] [ drop ] produce
        ] with-input-stream*
    ] [ FreeEnvironmentStrings win32-error=0/f ] bi ;