X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/0e06870bf080a38cda51c06c6612359afc2334e1..e463df90b78a57edd46d5b19a56006b28f5029d6:/lib/open.pm diff --git a/lib/open.pm b/lib/open.pm index 1e073c2..fd22e1b 100644 --- a/lib/open.pm +++ b/lib/open.pm @@ -1,28 +1,93 @@ package open; -use Carp; -$open::hint_bits = 0x20000; +use warnings; -use vars qw(%layers @layers); +our $VERSION = '1.10'; -# Populate hash in non-PerlIO case -%layers = (crlf => 1, raw => 0) unless (@layers); +require 5.008001; # for PerlIO::get_layers() -our $VERSION = '1.00'; +my $locale_encoding; + +sub _get_encname { + return ($1, Encode::resolve_alias($1)) if $_[0] =~ /^:?encoding\((.+)\)$/; + return; +} + +sub croak { + require Carp; goto &Carp::croak; +} + +sub _drop_oldenc { + # If by the time we arrive here there already is at the top of the + # perlio layer stack an encoding identical to what we would like + # to push via this open pragma, we will pop away the old encoding + # (+utf8) so that we can push ourselves in place (this is easier + # than ignoring pushing ourselves because of the way how ${^OPEN} + # works). So we are looking for something like + # + # stdio encoding(xxx) utf8 + # + # in the existing layer stack, and in the new stack chunk for + # + # :encoding(xxx) + # + # If we find a match, we pop the old stack (once, since + # the utf8 is just a flag on the encoding layer) + my ($h, @new) = @_; + return unless @new >= 1 && $new[-1] =~ /^:encoding\(.+\)$/; + my @old = PerlIO::get_layers($h); + return unless @old >= 3 && + $old[-1] eq 'utf8' && + $old[-2] =~ /^encoding\(.+\)$/; + require Encode; + my ($loname, $lcname) = _get_encname($old[-2]); + unless (defined $lcname) { # Should we trust get_layers()? + croak("open: Unknown encoding '$loname'"); + } + my ($voname, $vcname) = _get_encname($new[-1]); + unless (defined $vcname) { + croak("open: Unknown encoding '$voname'"); + } + if ($lcname eq $vcname) { + binmode($h, ":pop"); # utf8 is part of the encoding layer + } +} sub import { - shift; - die "`use open' needs explicit list of disciplines" unless @_; - $^H |= $open::hint_bits; - my ($in,$out) = split(/\0/,(${^OPEN} || '\0')); - my @in = split(/\s+/,$in); - my @out = split(/\s+/,$out); - while (@_) { - my $type = shift; - my $discp = shift; + my ($class,@args) = @_; + croak("open: needs explicit list of PerlIO layers") unless @args; + my $std; + my ($in,$out) = split(/\0/,(${^OPEN} || "\0"), -1); + while (@args) { + my $type = shift(@args); + my $dscp; + if ($type =~ /^:?(utf8|locale|encoding\(.+\))$/) { + $type = 'IO'; + $dscp = ":$1"; + } elsif ($type eq ':std') { + $std = 1; + next; + } else { + $dscp = shift(@args) || ''; + } my @val; - foreach my $layer (split(/\s+:?/,$discp)) { - unless(exists $layers{$layer}) { - croak "Unknown discipline layer '$layer'"; + foreach my $layer (split(/\s+/,$dscp)) { + $layer =~ s/^://; + if ($layer eq 'locale') { + require Encode; + require encoding; + $locale_encoding = encoding::_get_locale_encoding() + unless defined $locale_encoding; + (warnings::warnif("layer", "Cannot figure out an encoding to use"), last) + unless defined $locale_encoding; + $layer = "encoding($locale_encoding)"; + $std = 1; + } else { + my $target = $layer; # the layer name itself + $target =~ s/^(\w+)\(.+\)$/$1/; # strip parameters + + unless(PerlIO::Layer::->find($target,1)) { + warnings::warnif("layer", "Unknown PerlIO layer '$target'"); + } } push(@val,":$layer"); if ($layer =~ /^(crlf|raw)$/) { @@ -30,16 +95,47 @@ sub import { } } if ($type eq 'IN') { - $in = join(' ',@val); + _drop_oldenc(*STDIN, @val) if $std; + $in = join(' ', @val); } elsif ($type eq 'OUT') { - $out = join(' ',@val); + if ($std) { + _drop_oldenc(*STDOUT, @val); + _drop_oldenc(*STDERR, @val); + } + $out = join(' ', @val); + } + elsif ($type eq 'IO') { + if ($std) { + _drop_oldenc(*STDIN, @val); + _drop_oldenc(*STDOUT, @val); + _drop_oldenc(*STDERR, @val); + } + $in = $out = join(' ', @val); } else { - croak "Unknown discipline class '$type'"; + croak "Unknown PerlIO layer class '$type' (need IN, OUT or IO)"; + } + } + ${^OPEN} = join("\0", $in, $out); + if ($std) { + if ($in) { + if ($in =~ /:utf8\b/) { + binmode(STDIN, ":utf8"); + } elsif ($in =~ /(\w+\(.+\))/) { + binmode(STDIN, ":$1"); + } + } + if ($out) { + if ($out =~ /:utf8\b/) { + binmode(STDOUT, ":utf8"); + binmode(STDERR, ":utf8"); + } elsif ($out =~ /(\w+\(.+\))/) { + binmode(STDOUT, ":$1"); + binmode(STDERR, ":$1"); + } } } - ${^OPEN} = join('\0',$in,$out); } 1; @@ -47,52 +143,124 @@ __END__ =head1 NAME -open - perl pragma to set default disciplines for input and output +open - perl pragma to set default PerlIO layers for input and output =head1 SYNOPSIS - use open IN => ":crlf", OUT => ":raw"; + use open IN => ":crlf", OUT => ":bytes"; + use open OUT => ':utf8'; + use open IO => ":encoding(iso-8859-7)"; + + use open IO => ':locale'; + + use open ':encoding(utf8)'; + use open ':locale'; + use open ':encoding(iso-8859-7)'; + + use open ':std'; =head1 DESCRIPTION -The open pragma is used to declare one or more default disciplines for -I/O operations. Any open() and readpipe() (aka qx//) operators found -within the lexical scope of this pragma will use the declared defaults. -Neither open() with an explicit set of disciplines, nor sysopen() are -influenced by this pragma. +Full-fledged support for I/O layers is now implemented provided +Perl is configured to use PerlIO as its IO system (which is now the +default). -Only the two pseudo-disciplines ":raw" and ":crlf" are currently -available. +The C pragma serves as one of the interfaces to declare default +"layers" (also known as "disciplines") for all I/O. Any two-argument +open(), readpipe() (aka qx//) and similar operators found within the +lexical scope of this pragma will use the declared defaults. +Even three-argument opens may be affected by this pragma +when they don't specify IO layers in MODE. -The ":raw" discipline corresponds to "binary mode" and the ":crlf" -discipline corresponds to "text mode" on platforms that distinguish -between the two modes when opening files (which is many DOS-like -platforms, including Windows). These two disciplines are currently -no-ops on platforms where binmode() is a no-op, but will be -supported everywhere in future. +With the C subpragma you can declare the default layers +of input streams, and with the C subpragma you can declare +the default layers of output streams. With the C subpragma +you can control both input and output streams simultaneously. + +If you have a legacy encoding, you can use the C<:encoding(...)> tag. + +If you want to set your encoding layers based on your +locale environment variables, you can use the C<:locale> tag. +For example: + + $ENV{LANG} = 'ru_RU.KOI8-R'; + # the :locale will probe the locale environment variables like LANG + use open OUT => ':locale'; + open(O, ">koi8"); + print O chr(0x430); # Unicode CYRILLIC SMALL LETTER A = KOI8-R 0xc1 + close O; + open(I, "), "\n"; # this should print 0xc1 + close I; + +These are equivalent + + use open ':encoding(utf8)'; + use open IO => ':encoding(utf8)'; + +as are these + + use open ':locale'; + use open IO => ':locale'; -=head1 UNIMPLEMENTED FUNCTIONALITY +and these -Full-fledged support for I/O disciplines is currently unimplemented. -When they are eventually supported, this pragma will serve as one of -the interfaces to declare default disciplines for all I/O. + use open ':encoding(iso-8859-7)'; + use open IO => ':encoding(iso-8859-7)'; + +The matching of encoding names is loose: case does not matter, and +many encodings have several aliases. See L for +details and the list of supported locales. + +When open() is given an explicit list of layers (with the three-arg +syntax), they override the list declared using this pragma. open() can +also be given a single colon (:) for a layer name, to override this pragma +and use the default (C<:raw> on Unix, C<:crlf> on Windows). + +The C<:std> subpragma on its own has no effect, but if combined with +the C<:utf8> or C<:encoding> subpragmas, it converts the standard +filehandles (STDIN, STDOUT, STDERR) to comply with encoding selected +for input/output handles. For example, if both input and out are +chosen to be C<:encoding(utf8)>, a C<:std> will mean that STDIN, STDOUT, +and STDERR are also in C<:encoding(utf8)>. On the other hand, if only +output is chosen to be in C<< :encoding(koi8r) >>, a C<:std> will cause +only the STDOUT and STDERR to be in C. The C<:locale> subpragma +implicitly turns on C<:std>. + +The logic of C<:locale> is described in full in L, +but in short it is first trying nl_langinfo(CODESET) and then +guessing from the LC_ALL and LANG locale environment variables. + +Directory handles may also support PerlIO layers in the future. + +=head1 NONPERLIO FUNCTIONALITY + +If Perl is not built to use PerlIO as its IO system then only the two +pseudo-layers C<:bytes> and C<:crlf> are available. + +The C<:bytes> layer corresponds to "binary mode" and the C<:crlf> +layer corresponds to "text mode" on platforms that distinguish +between the two modes when opening files (which is many DOS-like +platforms, including Windows). These two layers are no-ops on +platforms where binmode() is a no-op, but perform their functions +everywhere if PerlIO is enabled. -In future, any default disciplines declared by this pragma will be -available by the special discipline name ":DEFAULT", and could be used -within handle constructors that allow disciplines to be specified. -This would make it possible to stack new disciplines over the default -ones. +=head1 IMPLEMENTATION DETAILS - open FH, "<:para :DEFAULT", $file or die "can't open $file: $!"; +There is a class method in C C which is +implemented as XS code. It is called by C to validate the +layers: -Socket and directory handles will also support disciplines in -future. + PerlIO::Layer::->find("perlio") -Full support for I/O disciplines will enable all of the supported -disciplines to work on all platforms. +The return value (if defined) is a Perl object, of class +C which is created by the C code in F. As +yet there is nothing useful you can do with the object at the perl +level. =head1 SEE ALSO -L, L, L +L, L, L, L, +L =cut