perl/lib/FileHandle.pm

package FileHandle;

use 5.006;
use strict;
our($VERSION, @ISA, @EXPORT, @EXPORT_OK);

$VERSION = "2.01";

require IO::File;
@ISA = qw(IO::File);

@EXPORT = qw(_IOFBF _IOLBF _IONBF);

@EXPORT_OK = qw(
    pipe

    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

    print
    printf
    getline
    getlines
);

#
# Everything we're willing to export, we must first import.
#
import IO::Handle grep { !defined(&$_) } @EXPORT, @EXPORT_OK;

#
# Some people call "FileHandle::function", so all the functions
# that were in the old FileHandle class must be imported, too.
#
{
    no strict 'refs';

    my %import = (
        'IO::Handle' =>
            [qw(DESTROY new_from_fd fdopen close fileno getc ungetc gets
                eof flush error clearerr setbuf setvbuf _open_mode_string)],
        'IO::Seekable' =>
            [qw(seek tell getpos setpos)],
        'IO::File' =>
            [qw(new new_tmpfile open)]
    );
    for my $pkg (keys %import) {
        for my $func (@{$import{$pkg}}) {
            my $c = *{"${pkg}::$func"}{CODE}
                or die "${pkg}::$func missing";
            *$func = $c;
        }
    }
}

#
# Specialized importer for Fcntl magic.
#
sub import {
    my $pkg = shift;
    my $callpkg = caller;
    require Exporter;
    Exporter::export($pkg, $callpkg, @_);

    #
    # If the Fcntl extension is available,
    #  export its constants.
    #
    eval {
        require Fcntl;
        Exporter::export('Fcntl', $callpkg);
    };
}

################################################
# This is the only exported function we define;
# the rest come from other classes.
#

sub pipe {
    my $r = new IO::Handle;
    my $w = new IO::Handle;
    CORE::pipe($r, $w) or return undef;
    ($r, $w);
}

# Rebless standard file handles
bless *STDIN{IO},  "FileHandle" if ref *STDIN{IO}  eq "IO::Handle";
bless *STDOUT{IO}, "FileHandle" if ref *STDOUT{IO} eq "IO::Handle";
bless *STDERR{IO}, "FileHandle" if ref *STDERR{IO} eq "IO::Handle";

1;

__END__

=head1 NAME

FileHandle - supply object methods for filehandles

=head1 SYNOPSIS

    use FileHandle;

    $fh = new FileHandle;
    if ($fh->open("< file")) {
        print <$fh>;
        $fh->close;
    }

    $fh = new FileHandle "> FOO";
    if (defined $fh) {
        print $fh "bar\n";
        $fh->close;
    }

    $fh = new FileHandle "file", "r";
    if (defined $fh) {
        print <$fh>;
        undef $fh;       # automatically closes the file
    }

    $fh = new FileHandle "file", O_WRONLY|O_APPEND;
    if (defined $fh) {
        print $fh "corge\n";
        undef $fh;       # automatically closes the file
    }

    $pos = $fh->getpos;
    $fh->setpos($pos);

    $fh->setvbuf($buffer_var, _IOLBF, 1024);

    ($readfh, $writefh) = FileHandle::pipe;

    autoflush STDOUT 1;

=head1 DESCRIPTION

NOTE: This class is now a front-end to the IO::* classes.

C<FileHandle::new> creates a C<FileHandle>, which is a reference to a
newly created symbol (see the C<Symbol> package).  If it receives any
parameters, they are passed to C<FileHandle::open>; if the open fails,
the C<FileHandle> object is destroyed.  Otherwise, it is returned to
the caller.

C<FileHandle::new_from_fd> creates a C<FileHandle> like C<new> does.
It requires two parameters, which are passed to C<FileHandle::fdopen>;
if the fdopen fails, the C<FileHandle> object is destroyed.
Otherwise, it is returned to the caller.

C<FileHandle::open> accepts one parameter or two.  With one parameter,
it is just a front end for the built-in C<open> function.  With two
parameters, the first parameter is a filename that may include
whitespace or other special characters, and the second parameter is
the open mode, optionally followed by a file permission value.

If C<FileHandle::open> receives a Perl mode string (">", "+<", etc.)
or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic
Perl C<open> operator.

If C<FileHandle::open> is given a numeric mode, it passes that mode
and the optional permissions value to the Perl C<sysopen> operator.
For convenience, C<FileHandle::import> tries to import the O_XXX
constants from the Fcntl module.  If dynamic loading is not available,
this may fail, but the rest of FileHandle will still work.

C<FileHandle::fdopen> is like C<open> except that its first parameter
is not a filename but rather a file handle name, a FileHandle object,
or a file descriptor number.

If the C functions fgetpos() and fsetpos() are available, then
C<FileHandle::getpos> returns an opaque value that represents the
current position of the FileHandle, and C<FileHandle::setpos> uses
that value to return to a previously visited position.

If the C function setvbuf() is available, then C<FileHandle::setvbuf>
sets the buffering policy for the FileHandle.  The calling sequence
for the Perl function is the same as its C counterpart, including the
macros C<_IOFBF>, C<_IOLBF>, and C<_IONBF>, except that the buffer
parameter specifies a scalar variable to use as a buffer.  WARNING: A
variable used as a buffer by C<FileHandle::setvbuf> must not be
modified in any way until the FileHandle is closed or until
C<FileHandle::setvbuf> is called again, or memory corruption may
result!

See L<perlfunc> for complete descriptions of each of the following
supported C<FileHandle> methods, which are just front ends for the
corresponding built-in functions:

    close
    fileno
    getc
    gets
    eof
    clearerr
    seek
    tell

See L<perlvar> for complete descriptions of each of the following
supported C<FileHandle> methods:

    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

Furthermore, for doing normal I/O you might need these:

=over 4

=item $fh->print

See L<perlfunc/print>.

=item $fh->printf

See L<perlfunc/printf>.

=item $fh->getline

This works like <$fh> 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.

=item $fh->getlines

This works like <$fh> 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.

=back

There are many other functions available since FileHandle is descended
from IO::File, IO::Seekable, and IO::Handle.  Please see those
respective pages for documentation on more functions.

=head1 SEE ALSO

The B<IO> extension,
L<perlfunc>, 
L<perlop/"I/O Operators">.

=cut
Revision:	1.1
Committed:	Thu Jun 30 14:27:08 2005 UTC (21 years, 3 months ago) by root
Branch:	MAIN
CVS Tags:	PERL-5-8-7, HEAD
Branch point for:	PERL
Log Message:	* empty log message *
#	Content
1	package FileHandle;
2
3	use 5.006;
4	use strict;
5	our($VERSION, @ISA, @EXPORT, @EXPORT_OK);
6
7	$VERSION = "2.01";
8
9	require IO::File;
10	@ISA = qw(IO::File);
11
12	@EXPORT = qw(_IOFBF _IOLBF _IONBF);
13
14	@EXPORT_OK = qw(
15	pipe
16
17	autoflush
18	output_field_separator
19	output_record_separator
20	input_record_separator
21	input_line_number
22	format_page_number
23	format_lines_per_page
24	format_lines_left
25	format_name
26	format_top_name
27	format_line_break_characters
28	format_formfeed
29
30	print
31	printf
32	getline
33	getlines
34	);
35
36	#
37	# Everything we're willing to export, we must first import.
38	#
39	import IO::Handle grep { !defined(&$_) } @EXPORT, @EXPORT_OK;
40
41	#
42	# Some people call "FileHandle::function", so all the functions
43	# that were in the old FileHandle class must be imported, too.
44	#
45	{
46	no strict 'refs';
47
48	my %import = (
49	'IO::Handle' =>
50	[qw(DESTROY new_from_fd fdopen close fileno getc ungetc gets
51	eof flush error clearerr setbuf setvbuf _open_mode_string)],
52	'IO::Seekable' =>
53	[qw(seek tell getpos setpos)],
54	'IO::File' =>
55	[qw(new new_tmpfile open)]
56	);
57	for my $pkg (keys %import) {
58	for my $func (@{$import{$pkg}}) {
59	my $c = *{"${pkg}::$func"}{CODE}
60	or die "${pkg}::$func missing";
61	*$func = $c;
62	}
63	}
64	}
65
66	#
67	# Specialized importer for Fcntl magic.
68	#
69	sub import {
70	my $pkg = shift;
71	my $callpkg = caller;
72	require Exporter;
73	Exporter::export($pkg, $callpkg, @_);
74
75	#
76	# If the Fcntl extension is available,
77	# export its constants.
78	#
79	eval {
80	require Fcntl;
81	Exporter::export('Fcntl', $callpkg);
82	};
83	}
84
85	################################################
86	# This is the only exported function we define;
87	# the rest come from other classes.
88	#
89
90	sub pipe {
91	my $r = new IO::Handle;
92	my $w = new IO::Handle;
93	CORE::pipe($r, $w) or return undef;
94	($r, $w);
95	}
96
97	# Rebless standard file handles
98	bless STDIN{IO}, "FileHandle" if ref STDIN{IO} eq "IO::Handle";
99	bless STDOUT{IO}, "FileHandle" if ref STDOUT{IO} eq "IO::Handle";
100	bless STDERR{IO}, "FileHandle" if ref STDERR{IO} eq "IO::Handle";
101
102	1;
103
104	__END__
105
106	=head1 NAME
107
108	FileHandle - supply object methods for filehandles
109
110	=head1 SYNOPSIS
111
112	use FileHandle;
113
114	$fh = new FileHandle;
115	if ($fh->open("< file")) {
116	print <$fh>;
117	$fh->close;
118	}
119
120	$fh = new FileHandle "> FOO";
121	if (defined $fh) {
122	print $fh "bar\n";
123	$fh->close;
124	}
125
126	$fh = new FileHandle "file", "r";
127	if (defined $fh) {
128	print <$fh>;
129	undef $fh; # automatically closes the file
130	}
131
132	$fh = new FileHandle "file", O_WRONLY\|O_APPEND;
133	if (defined $fh) {
134	print $fh "corge\n";
135	undef $fh; # automatically closes the file
136	}
137
138	$pos = $fh->getpos;
139	$fh->setpos($pos);
140
141	$fh->setvbuf($buffer_var, _IOLBF, 1024);
142
143	($readfh, $writefh) = FileHandle::pipe;
144
145	autoflush STDOUT 1;
146
147	=head1 DESCRIPTION
148
149	NOTE: This class is now a front-end to the IO::* classes.
150
151	C<FileHandle::new> creates a C<FileHandle>, which is a reference to a
152	newly created symbol (see the C<Symbol> package). If it receives any
153	parameters, they are passed to C<FileHandle::open>; if the open fails,
154	the C<FileHandle> object is destroyed. Otherwise, it is returned to
155	the caller.
156
157	C<FileHandle::new_from_fd> creates a C<FileHandle> like C<new> does.
158	It requires two parameters, which are passed to C<FileHandle::fdopen>;
159	if the fdopen fails, the C<FileHandle> object is destroyed.
160	Otherwise, it is returned to the caller.
161
162	C<FileHandle::open> accepts one parameter or two. With one parameter,
163	it is just a front end for the built-in C<open> function. With two
164	parameters, the first parameter is a filename that may include
165	whitespace or other special characters, and the second parameter is
166	the open mode, optionally followed by a file permission value.
167
168	If C<FileHandle::open> receives a Perl mode string (">", "+<", etc.)
169	or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic
170	Perl C<open> operator.
171
172	If C<FileHandle::open> is given a numeric mode, it passes that mode
173	and the optional permissions value to the Perl C<sysopen> operator.
174	For convenience, C<FileHandle::import> tries to import the O_XXX
175	constants from the Fcntl module. If dynamic loading is not available,
176	this may fail, but the rest of FileHandle will still work.
177
178	C<FileHandle::fdopen> is like C<open> except that its first parameter
179	is not a filename but rather a file handle name, a FileHandle object,
180	or a file descriptor number.
181
182	If the C functions fgetpos() and fsetpos() are available, then
183	C<FileHandle::getpos> returns an opaque value that represents the
184	current position of the FileHandle, and C<FileHandle::setpos> uses
185	that value to return to a previously visited position.
186
187	If the C function setvbuf() is available, then C<FileHandle::setvbuf>
188	sets the buffering policy for the FileHandle. The calling sequence
189	for the Perl function is the same as its C counterpart, including the
190	macros C<_IOFBF>, C<_IOLBF>, and C<_IONBF>, except that the buffer
191	parameter specifies a scalar variable to use as a buffer. WARNING: A
192	variable used as a buffer by C<FileHandle::setvbuf> must not be
193	modified in any way until the FileHandle is closed or until
194	C<FileHandle::setvbuf> is called again, or memory corruption may
195	result!
196
197	See L<perlfunc> for complete descriptions of each of the following
198	supported C<FileHandle> methods, which are just front ends for the
199	corresponding built-in functions:
200
201	close
202	fileno
203	getc
204	gets
205	eof
206	clearerr
207	seek
208	tell
209
210	See L<perlvar> for complete descriptions of each of the following
211	supported C<FileHandle> methods:
212
213	autoflush
214	output_field_separator
215	output_record_separator
216	input_record_separator
217	input_line_number
218	format_page_number
219	format_lines_per_page
220	format_lines_left
221	format_name
222	format_top_name
223	format_line_break_characters
224	format_formfeed
225
226	Furthermore, for doing normal I/O you might need these:
227
228	=over 4
229
230	=item $fh->print
231
232	See L<perlfunc/print>.
233
234	=item $fh->printf
235
236	See L<perlfunc/printf>.
237
238	=item $fh->getline
239
240	This works like <$fh> described in L<perlop/"I/O Operators">
241	except that it's more readable and can be safely called in a
242	list context but still returns just one line.
243
244	=item $fh->getlines
245
246	This works like <$fh> when called in a list context to
247	read all the remaining lines in a file, except that it's more readable.
248	It will also croak() if accidentally called in a scalar context.
249
250	=back
251
252	There are many other functions available since FileHandle is descended
253	from IO::File, IO::Seekable, and IO::Handle. Please see those
254	respective pages for documentation on more functions.
255
256	=head1 SEE ALSO
257
258	The B<IO> extension,
259	L<perlfunc>,
260	L<perlop/"I/O Operators">.
261
262	=cut