mirror of
https://git.savannah.gnu.org/git/parallel.git
synced 2024-11-25 07:27:55 +00:00
647 lines
16 KiB
Perl
647 lines
16 KiB
Perl
package IO::Handle;
|
|
|
|
=head1 NAME
|
|
|
|
IO::Handle - supply object methods for I/O handles
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
use IO::Handle;
|
|
|
|
$io = IO::Handle->new();
|
|
if ($io->fdopen(fileno(STDIN),"r")) {
|
|
print $io->getline;
|
|
$io->close;
|
|
}
|
|
|
|
$io = IO::Handle->new();
|
|
if ($io->fdopen(fileno(STDOUT),"w")) {
|
|
$io->print("Some text\n");
|
|
}
|
|
|
|
# setvbuf is not available by default on Perls 5.8.0 and later.
|
|
use IO::Handle '_IOLBF';
|
|
$io->setvbuf($buffer_var, _IOLBF, 1024);
|
|
|
|
undef $io; # automatically closes the file if it's open
|
|
|
|
autoflush STDOUT 1;
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
C<IO::Handle> is the base class for all other IO handle classes. It is
|
|
not intended that objects of C<IO::Handle> would be created directly,
|
|
but instead C<IO::Handle> is inherited from by several other classes
|
|
in the IO hierarchy.
|
|
|
|
If you are reading this documentation, looking for a replacement for
|
|
the C<FileHandle> package, then I suggest you read the documentation
|
|
for C<IO::File> too.
|
|
|
|
=head1 CONSTRUCTOR
|
|
|
|
=over 4
|
|
|
|
=item new ()
|
|
|
|
Creates a new C<IO::Handle> object.
|
|
|
|
=item new_from_fd ( FD, MODE )
|
|
|
|
Creates an C<IO::Handle> like C<new> does.
|
|
It requires two parameters, which are passed to the method C<fdopen>;
|
|
if the fdopen fails, the object is destroyed. Otherwise, it is returned
|
|
to the caller.
|
|
|
|
=back
|
|
|
|
=head1 METHODS
|
|
|
|
See L<perlfunc> for complete descriptions of each of the following
|
|
supported C<IO::Handle> methods, which are just front ends for the
|
|
corresponding built-in functions:
|
|
|
|
$io->close
|
|
$io->eof
|
|
$io->fcntl( FUNCTION, SCALAR )
|
|
$io->fileno
|
|
$io->format_write( [FORMAT_NAME] )
|
|
$io->getc
|
|
$io->ioctl( FUNCTION, SCALAR )
|
|
$io->read ( BUF, LEN, [OFFSET] )
|
|
$io->print ( ARGS )
|
|
$io->printf ( FMT, [ARGS] )
|
|
$io->say ( ARGS )
|
|
$io->stat
|
|
$io->sysread ( BUF, LEN, [OFFSET] )
|
|
$io->syswrite ( BUF, [LEN, [OFFSET]] )
|
|
$io->truncate ( LEN )
|
|
|
|
See L<perlvar> for complete descriptions of each of the following
|
|
supported C<IO::Handle> methods. All of them return the previous
|
|
value of the attribute and takes an optional single argument that when
|
|
given will set the value. If no argument is given the previous value
|
|
is unchanged (except for $io->autoflush will actually turn ON
|
|
autoflush by default).
|
|
|
|
$io->autoflush ( [BOOL] ) $|
|
|
$io->format_page_number( [NUM] ) $%
|
|
$io->format_lines_per_page( [NUM] ) $=
|
|
$io->format_lines_left( [NUM] ) $-
|
|
$io->format_name( [STR] ) $~
|
|
$io->format_top_name( [STR] ) $^
|
|
$io->input_line_number( [NUM]) $.
|
|
|
|
The following methods are not supported on a per-filehandle basis.
|
|
|
|
IO::Handle->format_line_break_characters( [STR] ) $:
|
|
IO::Handle->format_formfeed( [STR]) $^L
|
|
IO::Handle->output_field_separator( [STR] ) $,
|
|
IO::Handle->output_record_separator( [STR] ) $\
|
|
|
|
IO::Handle->input_record_separator( [STR] ) $/
|
|
|
|
Furthermore, for doing normal I/O you might need these:
|
|
|
|
=over 4
|
|
|
|
=item $io->fdopen ( FD, MODE )
|
|
|
|
C<fdopen> is like an ordinary C<open> except that its first parameter
|
|
is not a filename but rather a file handle name, an IO::Handle object,
|
|
or a file descriptor number. (For the documentation of the C<open>
|
|
method, see L<IO::File>.)
|
|
|
|
=item $io->opened
|
|
|
|
Returns true if the object is currently a valid file descriptor, false
|
|
otherwise.
|
|
|
|
=item $io->getline
|
|
|
|
This works like <$io> described in L<perlop/"I/O Operators">
|
|
except that it's more readable and can be safely called in a
|
|
list context but still returns just one line. If used as the conditional
|
|
+within a C<while> or C-style C<for> loop, however, you will need to
|
|
+emulate the functionality of <$io> with C<< defined($_ = $io->getline) >>.
|
|
|
|
=item $io->getlines
|
|
|
|
This works like <$io> when called in a list context to read all
|
|
the remaining lines in a file, except that it's more readable.
|
|
It will also croak() if accidentally called in a scalar context.
|
|
|
|
=item $io->ungetc ( ORD )
|
|
|
|
Pushes a character with the given ordinal value back onto the given
|
|
handle's input stream. Only one character of pushback per handle is
|
|
guaranteed.
|
|
|
|
=item $io->write ( BUF, LEN [, OFFSET ] )
|
|
|
|
This C<write> is like C<write> found in C, that is it is the
|
|
opposite of read. The wrapper for the perl C<write> function is
|
|
called C<format_write>.
|
|
|
|
=item $io->error
|
|
|
|
Returns a true value if the given handle has experienced any errors
|
|
since it was opened or since the last call to C<clearerr>, or if the
|
|
handle is invalid. It only returns false for a valid handle with no
|
|
outstanding errors.
|
|
|
|
=item $io->clearerr
|
|
|
|
Clear the given handle's error indicator. Returns -1 if the handle is
|
|
invalid, 0 otherwise.
|
|
|
|
=item $io->sync
|
|
|
|
C<sync> synchronizes a file's in-memory state with that on the
|
|
physical medium. C<sync> does not operate at the perlio api level, but
|
|
operates on the file descriptor (similar to sysread, sysseek and
|
|
systell). This means that any data held at the perlio api level will not
|
|
be synchronized. To synchronize data that is buffered at the perlio api
|
|
level you must use the flush method. C<sync> is not implemented on all
|
|
platforms. Returns "0 but true" on success, C<undef> on error, C<undef>
|
|
for an invalid handle. See L<fsync(3c)>.
|
|
|
|
=item $io->flush
|
|
|
|
C<flush> causes perl to flush any buffered data at the perlio api level.
|
|
Any unread data in the buffer will be discarded, and any unwritten data
|
|
will be written to the underlying file descriptor. Returns "0 but true"
|
|
on success, C<undef> on error.
|
|
|
|
=item $io->printflush ( ARGS )
|
|
|
|
Turns on autoflush, print ARGS and then restores the autoflush status of the
|
|
C<IO::Handle> object. Returns the return value from print.
|
|
|
|
=item $io->blocking ( [ BOOL ] )
|
|
|
|
If called with an argument C<blocking> will turn on non-blocking IO if
|
|
C<BOOL> is false, and turn it off if C<BOOL> is true.
|
|
|
|
C<blocking> will return the value of the previous setting, or the
|
|
current setting if C<BOOL> is not given.
|
|
|
|
If an error occurs C<blocking> will return undef and C<$!> will be set.
|
|
|
|
=back
|
|
|
|
|
|
If the C functions setbuf() and/or setvbuf() are available, then
|
|
C<IO::Handle::setbuf> and C<IO::Handle::setvbuf> set the buffering
|
|
policy for an IO::Handle. The calling sequences for the Perl functions
|
|
are the same as their C counterparts--including the constants C<_IOFBF>,
|
|
C<_IOLBF>, and C<_IONBF> for setvbuf()--except that the buffer parameter
|
|
specifies a scalar variable to use as a buffer. You should only
|
|
change the buffer before any I/O, or immediately after calling flush.
|
|
|
|
WARNING: The IO::Handle::setvbuf() is not available by default on
|
|
Perls 5.8.0 and later because setvbuf() is rather specific to using
|
|
the stdio library, while Perl prefers the new perlio subsystem instead.
|
|
|
|
WARNING: A variable used as a buffer by C<setbuf> or C<setvbuf> B<must not
|
|
be modified> in any way until the IO::Handle is closed or C<setbuf> or
|
|
C<setvbuf> is called again, or memory corruption may result! Remember that
|
|
the order of global destruction is undefined, so even if your buffer
|
|
variable remains in scope until program termination, it may be undefined
|
|
before the file IO::Handle is closed. Note that you need to import the
|
|
constants C<_IOFBF>, C<_IOLBF>, and C<_IONBF> explicitly. Like C, setbuf
|
|
returns nothing. setvbuf returns "0 but true", on success, C<undef> on
|
|
failure.
|
|
|
|
Lastly, there is a special method for working under B<-T> and setuid/gid
|
|
scripts:
|
|
|
|
=over 4
|
|
|
|
=item $io->untaint
|
|
|
|
Marks the object as taint-clean, and as such data read from it will also
|
|
be considered taint-clean. Note that this is a very trusting action to
|
|
take, and appropriate consideration for the data source and potential
|
|
vulnerability should be kept in mind. Returns 0 on success, -1 if setting
|
|
the taint-clean flag failed. (eg invalid handle)
|
|
|
|
=back
|
|
|
|
=head1 NOTE
|
|
|
|
An C<IO::Handle> object is a reference to a symbol/GLOB reference (see
|
|
the C<Symbol> package). Some modules that
|
|
inherit from C<IO::Handle> may want to keep object related variables
|
|
in the hash table part of the GLOB. In an attempt to prevent modules
|
|
trampling on each other I propose the that any such module should prefix
|
|
its variables with its own name separated by _'s. For example the IO::Socket
|
|
module keeps a C<timeout> variable in 'io_socket_timeout'.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<perlfunc>,
|
|
L<perlop/"I/O Operators">,
|
|
L<IO::File>
|
|
|
|
=head1 BUGS
|
|
|
|
Due to backwards compatibility, all filehandles resemble objects
|
|
of class C<IO::Handle>, or actually classes derived from that class.
|
|
They actually aren't. Which means you can't derive your own
|
|
class from C<IO::Handle> and inherit those methods.
|
|
|
|
=head1 HISTORY
|
|
|
|
Derived from FileHandle.pm by Graham Barr E<lt>F<gbarr@pobox.com>E<gt>
|
|
|
|
=cut
|
|
|
|
use 5.006_001;
|
|
use strict;
|
|
our($VERSION, @EXPORT_OK, @ISA);
|
|
use Carp;
|
|
use Symbol;
|
|
use SelectSaver;
|
|
use IO (); # Load the XS module
|
|
|
|
require Exporter;
|
|
@ISA = qw(Exporter);
|
|
|
|
$VERSION = "1.31";
|
|
$VERSION = eval $VERSION;
|
|
|
|
@EXPORT_OK = qw(
|
|
autoflush
|
|
output_field_separator
|
|
output_record_separator
|
|
input_record_separator
|
|
input_line_number
|
|
format_page_number
|
|
format_lines_per_page
|
|
format_lines_left
|
|
format_name
|
|
format_top_name
|
|
format_line_break_characters
|
|
format_formfeed
|
|
format_write
|
|
|
|
print
|
|
printf
|
|
say
|
|
getline
|
|
getlines
|
|
|
|
printflush
|
|
flush
|
|
|
|
SEEK_SET
|
|
SEEK_CUR
|
|
SEEK_END
|
|
_IOFBF
|
|
_IOLBF
|
|
_IONBF
|
|
);
|
|
|
|
################################################
|
|
## Constructors, destructors.
|
|
##
|
|
|
|
sub new {
|
|
my $class = ref($_[0]) || $_[0] || "IO::Handle";
|
|
if (@_ != 1) {
|
|
# Since perl will automatically require IO::File if needed, but
|
|
# also initialises IO::File's @ISA as part of the core we must
|
|
# ensure IO::File is loaded if IO::Handle is. This avoids effect-
|
|
# ively "half-loading" IO::File.
|
|
if ($] > 5.013 && $class eq 'IO::File' && !$INC{"IO/File.pm"}) {
|
|
require IO::File;
|
|
shift;
|
|
return IO::File::->new(@_);
|
|
}
|
|
croak "usage: $class->new()";
|
|
}
|
|
my $io = gensym;
|
|
bless $io, $class;
|
|
}
|
|
|
|
sub new_from_fd {
|
|
my $class = ref($_[0]) || $_[0] || "IO::Handle";
|
|
@_ == 3 or croak "usage: $class->new_from_fd(FD, MODE)";
|
|
my $io = gensym;
|
|
shift;
|
|
IO::Handle::fdopen($io, @_)
|
|
or return undef;
|
|
bless $io, $class;
|
|
}
|
|
|
|
#
|
|
# There is no need for DESTROY to do anything, because when the
|
|
# last reference to an IO object is gone, Perl automatically
|
|
# closes its associated files (if any). However, to avoid any
|
|
# attempts to autoload DESTROY, we here define it to do nothing.
|
|
#
|
|
sub DESTROY {}
|
|
|
|
|
|
################################################
|
|
## Open and close.
|
|
##
|
|
|
|
sub _open_mode_string {
|
|
my ($mode) = @_;
|
|
$mode =~ /^\+?(<|>>?)$/
|
|
or $mode =~ s/^r(\+?)$/$1</
|
|
or $mode =~ s/^w(\+?)$/$1>/
|
|
or $mode =~ s/^a(\+?)$/$1>>/
|
|
or croak "IO::Handle: bad open mode: $mode";
|
|
$mode;
|
|
}
|
|
|
|
sub fdopen {
|
|
@_ == 3 or croak 'usage: $io->fdopen(FD, MODE)';
|
|
my ($io, $fd, $mode) = @_;
|
|
local(*GLOB);
|
|
|
|
if (ref($fd) && "".$fd =~ /GLOB\(/o) {
|
|
# It's a glob reference; Alias it as we cannot get name of anon GLOBs
|
|
my $n = qualify(*GLOB);
|
|
*GLOB = *{*$fd};
|
|
$fd = $n;
|
|
} elsif ($fd =~ m#^\d+$#) {
|
|
# It's an FD number; prefix with "=".
|
|
$fd = "=$fd";
|
|
}
|
|
|
|
open($io, _open_mode_string($mode) . '&' . $fd)
|
|
? $io : undef;
|
|
}
|
|
|
|
sub close {
|
|
@_ == 1 or croak 'usage: $io->close()';
|
|
my($io) = @_;
|
|
|
|
close($io);
|
|
}
|
|
|
|
################################################
|
|
## Normal I/O functions.
|
|
##
|
|
|
|
# flock
|
|
# select
|
|
|
|
sub opened {
|
|
@_ == 1 or croak 'usage: $io->opened()';
|
|
defined fileno($_[0]);
|
|
}
|
|
|
|
sub fileno {
|
|
@_ == 1 or croak 'usage: $io->fileno()';
|
|
fileno($_[0]);
|
|
}
|
|
|
|
sub getc {
|
|
@_ == 1 or croak 'usage: $io->getc()';
|
|
getc($_[0]);
|
|
}
|
|
|
|
sub eof {
|
|
@_ == 1 or croak 'usage: $io->eof()';
|
|
eof($_[0]);
|
|
}
|
|
|
|
sub print {
|
|
@_ or croak 'usage: $io->print(ARGS)';
|
|
my $this = shift;
|
|
print $this @_;
|
|
}
|
|
|
|
sub printf {
|
|
@_ >= 2 or croak 'usage: $io->printf(FMT,[ARGS])';
|
|
my $this = shift;
|
|
printf $this @_;
|
|
}
|
|
|
|
sub say {
|
|
@_ or croak 'usage: $io->say(ARGS)';
|
|
my $this = shift;
|
|
local $\ = "\n";
|
|
print $this @_;
|
|
}
|
|
|
|
sub getline {
|
|
@_ == 1 or croak 'usage: $io->getline()';
|
|
my $this = shift;
|
|
return scalar <$this>;
|
|
}
|
|
|
|
*gets = \&getline; # deprecated
|
|
|
|
sub getlines {
|
|
@_ == 1 or croak 'usage: $io->getlines()';
|
|
wantarray or
|
|
croak 'Can\'t call $io->getlines in a scalar context, use $io->getline';
|
|
my $this = shift;
|
|
return <$this>;
|
|
}
|
|
|
|
sub truncate {
|
|
@_ == 2 or croak 'usage: $io->truncate(LEN)';
|
|
truncate($_[0], $_[1]);
|
|
}
|
|
|
|
sub read {
|
|
@_ == 3 || @_ == 4 or croak 'usage: $io->read(BUF, LEN [, OFFSET])';
|
|
read($_[0], $_[1], $_[2], $_[3] || 0);
|
|
}
|
|
|
|
sub sysread {
|
|
@_ == 3 || @_ == 4 or croak 'usage: $io->sysread(BUF, LEN [, OFFSET])';
|
|
sysread($_[0], $_[1], $_[2], $_[3] || 0);
|
|
}
|
|
|
|
sub write {
|
|
@_ >= 2 && @_ <= 4 or croak 'usage: $io->write(BUF [, LEN [, OFFSET]])';
|
|
local($\) = "";
|
|
$_[2] = length($_[1]) unless defined $_[2];
|
|
print { $_[0] } substr($_[1], $_[3] || 0, $_[2]);
|
|
}
|
|
|
|
sub syswrite {
|
|
@_ >= 2 && @_ <= 4 or croak 'usage: $io->syswrite(BUF [, LEN [, OFFSET]])';
|
|
if (defined($_[2])) {
|
|
syswrite($_[0], $_[1], $_[2], $_[3] || 0);
|
|
} else {
|
|
syswrite($_[0], $_[1]);
|
|
}
|
|
}
|
|
|
|
sub stat {
|
|
@_ == 1 or croak 'usage: $io->stat()';
|
|
stat($_[0]);
|
|
}
|
|
|
|
################################################
|
|
## State modification functions.
|
|
##
|
|
|
|
sub autoflush {
|
|
my $old = new SelectSaver qualify($_[0], caller);
|
|
my $prev = $|;
|
|
$| = @_ > 1 ? $_[1] : 1;
|
|
$prev;
|
|
}
|
|
|
|
sub output_field_separator {
|
|
carp "output_field_separator is not supported on a per-handle basis"
|
|
if ref($_[0]);
|
|
my $prev = $,;
|
|
$, = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub output_record_separator {
|
|
carp "output_record_separator is not supported on a per-handle basis"
|
|
if ref($_[0]);
|
|
my $prev = $\;
|
|
$\ = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub input_record_separator {
|
|
carp "input_record_separator is not supported on a per-handle basis"
|
|
if ref($_[0]);
|
|
my $prev = $/;
|
|
$/ = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub input_line_number {
|
|
local $.;
|
|
() = tell qualify($_[0], caller) if ref($_[0]);
|
|
my $prev = $.;
|
|
$. = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub format_page_number {
|
|
my $old;
|
|
$old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
|
|
my $prev = $%;
|
|
$% = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub format_lines_per_page {
|
|
my $old;
|
|
$old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
|
|
my $prev = $=;
|
|
$= = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub format_lines_left {
|
|
my $old;
|
|
$old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
|
|
my $prev = $-;
|
|
$- = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub format_name {
|
|
my $old;
|
|
$old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
|
|
my $prev = $~;
|
|
$~ = qualify($_[1], caller) if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub format_top_name {
|
|
my $old;
|
|
$old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
|
|
my $prev = $^;
|
|
$^ = qualify($_[1], caller) if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub format_line_break_characters {
|
|
carp "format_line_break_characters is not supported on a per-handle basis"
|
|
if ref($_[0]);
|
|
my $prev = $:;
|
|
$: = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub format_formfeed {
|
|
carp "format_formfeed is not supported on a per-handle basis"
|
|
if ref($_[0]);
|
|
my $prev = $^L;
|
|
$^L = $_[1] if @_ > 1;
|
|
$prev;
|
|
}
|
|
|
|
sub formline {
|
|
my $io = shift;
|
|
my $picture = shift;
|
|
local($^A) = $^A;
|
|
local($\) = "";
|
|
formline($picture, @_);
|
|
print $io $^A;
|
|
}
|
|
|
|
sub format_write {
|
|
@_ < 3 || croak 'usage: $io->write( [FORMAT_NAME] )';
|
|
if (@_ == 2) {
|
|
my ($io, $fmt) = @_;
|
|
my $oldfmt = $io->format_name(qualify($fmt,caller));
|
|
CORE::write($io);
|
|
$io->format_name($oldfmt);
|
|
} else {
|
|
CORE::write($_[0]);
|
|
}
|
|
}
|
|
|
|
sub fcntl {
|
|
@_ == 3 || croak 'usage: $io->fcntl( OP, VALUE );';
|
|
my ($io, $op) = @_;
|
|
return fcntl($io, $op, $_[2]);
|
|
}
|
|
|
|
sub ioctl {
|
|
@_ == 3 || croak 'usage: $io->ioctl( OP, VALUE );';
|
|
my ($io, $op) = @_;
|
|
return ioctl($io, $op, $_[2]);
|
|
}
|
|
|
|
# this sub is for compatibility with older releases of IO that used
|
|
# a sub called constant to determine if a constant existed -- GMB
|
|
#
|
|
# The SEEK_* and _IO?BF constants were the only constants at that time
|
|
# any new code should just chech defined(&CONSTANT_NAME)
|
|
|
|
sub constant {
|
|
no strict 'refs';
|
|
my $name = shift;
|
|
(($name =~ /^(SEEK_(SET|CUR|END)|_IO[FLN]BF)$/) && defined &{$name})
|
|
? &{$name}() : undef;
|
|
}
|
|
|
|
|
|
# so that flush.pl can be deprecated
|
|
|
|
sub printflush {
|
|
my $io = shift;
|
|
my $old;
|
|
$old = new SelectSaver qualify($io, caller) if ref($io);
|
|
local $| = 1;
|
|
if(ref($io)) {
|
|
print $io @_;
|
|
}
|
|
else {
|
|
print @_;
|
|
}
|
|
}
|
|
|
|
1;
|