File Coverage

blib/lib/File/Next.pm

Criterion	Covered	Total	%
statement	139	148	93.9
branch	63	74	85.1
condition	22	36	61.1
subroutine	18	18	100.0
pod	7	7	100.0
total	249	283	87.9

package File::Next;

use strict;
use warnings;

=head1 NAME

File::Next - File-finding iterator

=head1 VERSION

Version 1.16

=cut

our $VERSION = '1.16';

=head1 SYNOPSIS

File::Next is a lightweight, taint-safe file-finding module.
It's lightweight and has no non-core prerequisites.

    use File::Next;

    my $files = File::Next::files( '/tmp' );

    while ( defined ( my $file = $files->() ) ) {
        # do something...
    }

=head1 OPERATIONAL THEORY

The two major functions, I and I, return an iterator
that will walk through a directory tree.  The simplest use case is:

    use File::Next;

    my $iter = File::Next::files( '/tmp' );

    while ( defined ( my $file = $iter->() ) ) {
        print $file, "\n";
    }

    # Prints...
    /tmp/foo.txt
    /tmp/bar.pl
    /tmp/baz/1
    /tmp/baz/2.txt
    /tmp/baz/wango/tango/purple.txt

Note that only files are returned by C's iterator.
Directories are ignored.

In list context, the iterator returns a list containing I<$dir>,
I<$file> and I<$fullpath>, where I<$fullpath> is what would get
returned in scalar context.

The first parameter to any of the iterator factory functions may
be a hashref of options.

=head1 ITERATORS

For the three iterators, the \%options are optional.

=head2 files( [ \%options, ] @starting_points )

Returns an iterator that walks directories starting with the items
in I<@starting_points>.  Each call to the iterator returns another
regular file.

=head2 dirs( [ \%options, ] @starting_points )

Returns an iterator that walks directories starting with the items
in I<@starting_points>.  Each call to the iterator returns another
directory.

=head2 everything( [ \%options, ] @starting_points )

Returns an iterator that walks directories starting with the items
in I<@starting_points>.  Each call to the iterator returns another
file, whether it's a regular file, directory, symlink, socket, or
whatever.

=head2 from_file( [ \%options, ] $filename )

Returns an iterator that iterates over each of the files specified
in I<$filename>.  If I<$filename> is C<->, then the files are read
from STDIN.

The files are assumed to be in the file one filename per line.  If
I<$nul_separated> is passed, then the files are assumed to be
NUL-separated, as by C.

If there are blank lines or empty filenames in the input stream,
they are ignored.

Each filename is checked to see that it is a regular file or a named
pipe.  If the file does not exists or is a directory, then a warning
is thrown to I, and the file is skipped.

The following options have no effect in C: I,
I, I.

=head1 SUPPORT FUNCTIONS

=head2 sort_standard( $a, $b )

A sort function for passing as a C option:

    my $iter = File::Next::files( {
        sort_files => \&File::Next::sort_standard,
    }, 't/swamp' );

This function is the default, so the code above is identical to:

    my $iter = File::Next::files( {
        sort_files => 1,
    }, 't/swamp' );

=head2 sort_reverse( $a, $b )

Same as C, but in reverse.

=head2 reslash( $path )

Takes a path with all forward slashes and rebuilds it with whatever
is appropriate for the platform.  For example 'foo/bar/bat' will
become 'foo\bar\bat' on Windows.

This is really just a convenience function.  I'd make it private,
but F wants it, too.

=cut

=head1 CONSTRUCTOR PARAMETERS

=head2 file_filter -> \&file_filter

The file_filter lets you check to see if it's really a file you
want to get back.  If the file_filter returns a true value, the
file will be returned; if false, it will be skipped.

The file_filter function takes no arguments but rather does its work through
a collection of variables.

=over 4

=item * C<$_> is the current filename within that directory

=item * C<$File::Next::dir> is the current directory name

=item * C<$File::Next::name> is the complete pathname to the file

=back

These are analogous to the same variables in L.

    my $iter = File::Next::files( { file_filter => sub { /\.txt$/ } }, '/tmp' );

By default, the I is C, or "all files".

This filter has no effect if your iterator is only returning directories.

=head2 descend_filter => \&descend_filter

The descend_filter lets you check to see if the iterator should
descend into a given directory.  Maybe you want to skip F and
F<.svn> directories.

    my $descend_filter = sub { $_ ne "CVS" && $_ ne ".svn" }

The descend_filter function takes no arguments but rather does its work through
a collection of variables.

=over 4

=item * C<$_> is the current filename of the directory

=item * C<$File::Next::dir> is the complete directory name

=back

The descend filter is NOT applied to any directory names specified
as I<@starting_points> in the constructor.  For example,

    my $iter = File::Next::files( { descend_filter => sub{0} }, '/tmp' );

always descends into I, as you would expect.

By default, the I is C, or "always descend".

=head2 error_handler => \&error_handler

If I is set, then any errors will be sent through
it.  If the error is OS-related (ex. file not found, not permissions), the
native error code is passed as a second argument.  By default, this value is
C.  This function must NOT return.

=head2 warning_handler => \&warning_handler

If I is set, then any errors will be sent through
it.  By default, this value is C.  Unlike the
I, this function must return.

=head2 sort_files => [ 0 | 1 | \&sort_sub]

If you want files sorted, pass in some true value, as in
C<< sort_files => 1 >>.

If you want a special sort order, pass in a sort function like
C<< sort_files => sub { $a->[1] cmp $b->[1] } >>.
Note that the parms passed in to the sub are arrayrefs, where $a->[0]
is the directory name, $a->[1] is the file name and $a->[2] is the
full path.  Typically you're going to be sorting on $a->[2].

=head2 follow_symlinks => [ 0 | 1 ]

If set to false, the iterator will ignore any files and directories
that are actually symlinks.  This has no effect on non-Unixy systems
such as Windows.  By default, this is true.

Note that this filter does not apply to any of the I<@starting_points>
passed in to the constructor.

You should not set C<< follow_symlinks => 0 >> unless you specifically
need that behavior.  Setting C<< follow_symlinks => 0 >> can be a
speed hit, because File::Next must check to see if the file or
directory you're about to follow is actually a symlink.

=head2 nul_separated => [ 0 | 1 ]

Used by the C iterator.  Specifies that the files
listed in the input file are separated by NUL characters, as from
the C command with the C<-print0> argument.

=cut

use File::Spec ();

our $name; # name of the current file
our $dir;  # dir of the current file

our %files_defaults;
our %skip_dirs;

BEGIN {
    %files_defaults = (
        file_filter     => undef,
        descend_filter  => undef,
        error_handler   => sub { CORE::die $_[0] },
        warning_handler => sub { CORE::warn @_ },
        sort_files      => undef,
        follow_symlinks => 1,
        nul_separated   => 0,
    );
    %skip_dirs = map {($_,1)} (File::Spec->curdir, File::Spec->updir);
}


sub files {
    die _bad_invocation() if @_ && defined($_[0]) && ($_[0] eq __PACKAGE__);

    my ($parms,@queue) = _setup( \%files_defaults, @_ );

    return sub {
        my $filter = $parms->{file_filter};
        while (@queue) {
            my ($dirname,$file,$fullpath) = splice( @queue, 0, 3 );
            if ( -f $fullpath || -p _ || $fullpath =~ m{^/dev/fd} ) {
                if ( $filter ) {
                    local $_ = $file;
                    local $File::Next::dir = $dirname;
                    local $File::Next::name = $fullpath;
                    next if not $filter->();
                }
                return wantarray ? ($dirname,$file,$fullpath) : $fullpath;
            }
            if ( -d _ ) {
                unshift( @queue, _candidate_files( $parms, $fullpath ) );
            }
        } # while

        return;
    }; # iterator
}


sub dirs {
    die _bad_invocation() if @_ && defined($_[0]) && ($_[0] eq __PACKAGE__);

    my ($parms,@queue) = _setup( \%files_defaults, @_ );

    return sub {
        while (@queue) {
            my (undef,undef,$fullpath) = splice( @queue, 0, 3 );
            if ( -d $fullpath ) {
                unshift( @queue, _candidate_files( $parms, $fullpath ) );
                return $fullpath;
            }
        } # while

        return;
    }; # iterator
}

sub everything {
    die _bad_invocation() if @_ && defined($_[0]) && ($_[0] eq __PACKAGE__);

    my ($parms,@queue) = _setup( \%files_defaults, @_ );

    return sub {
        my $filter = $parms->{file_filter};
        while (@queue) {
            my ($dirname,$file,$fullpath) = splice( @queue, 0, 3 );
            if ( -d $fullpath ) {
                unshift( @queue, _candidate_files( $parms, $fullpath ) );
            }
            if ( $filter ) {
                local $_ = $file;
                local $File::Next::dir  = $dirname;
                local $File::Next::name = $fullpath;
                next if not $filter->();
            }
            return wantarray ? ($dirname,$file,$fullpath) : $fullpath;
        } # while

        return;
    }; # iterator
}

sub from_file {
    die _bad_invocation() if @_ && defined($_[0]) && ($_[0] eq __PACKAGE__);

    my ($parms,@queue) = _setup( \%files_defaults, @_ );
    my $err  = $parms->{error_handler};
    my $warn = $parms->{warning_handler};

    my $filename = $queue[1];

    if ( !defined($filename) ) {
        $err->( 'Must pass a filename to from_file()' );
        return undef;
    }

    my $fh;
    if ( $filename eq '-' ) {
        $fh = \*STDIN;
    }
    else {
        if ( !open( $fh, '<', $filename ) ) {
            $err->( "Unable to open $filename: $!", $! + 0 );
            return undef;
        }
    }

    return sub {
        my $filter = $parms->{file_filter};
        local $/ = $parms->{nul_separated} ? "\x00" : $/;
        while ( my $fullpath = <$fh> ) {
            chomp $fullpath;
            next unless $fullpath =~ /./;
            if ( not ( -f $fullpath || -p _ ) ) {
                $warn->( "$fullpath: No such file" );
                next;
            }

            my ($volume,$dirname,$file) = File::Spec->splitpath( $fullpath );
            if ( $filter ) {
                local $_ = $file;
                local $File::Next::dir  = $dirname;
                local $File::Next::name = $fullpath;
                next if not $filter->();
            }
            return wantarray ? ($dirname,$file,$fullpath) : $fullpath;
        } # while
        close $fh;

        return;
    }; # iterator
}

sub _bad_invocation {
    my $good = (caller(1))[3];
    my $bad  = $good;
    $bad =~ s/(.+)::/$1->/;
    return "$good must not be invoked as $bad";
}

sub sort_standard($$)   { return $_[0]->[1] cmp $_[1]->[1] } ## no critic (ProhibitSubroutinePrototypes)
sub sort_reverse($$)    { return $_[1]->[1] cmp $_[0]->[1] } ## no critic (ProhibitSubroutinePrototypes)

sub reslash {
    my $path = shift;

    my @parts = split( /\//, $path );

    return $path if @parts < 2;

    return File::Spec->catfile( @parts );
}


=head1 PRIVATE FUNCTIONS

=head2 _setup( $default_parms, @whatever_was_passed_to_files() )

Handles all the scut-work for setting up the parms passed in.

Returns a hashref of operational options, combined between
I<$passed_parms> and I<$defaults>, plus the queue.

The queue prep stuff takes the strings in I<@starting_points> and
puts them in the format that queue needs.

The C<@queue> that gets passed around is an array that has three
elements for each of the entries in the queue: $dir, $file and
$fullpath.  Items must be pushed and popped off the queue three at
a time (spliced, really).

=cut

sub _setup {
    my $defaults = shift;
    my $passed_parms = ref $_[0] eq 'HASH' ? {%{+shift}} : {}; # copy parm hash

    my %passed_parms = %{$passed_parms};

    my $parms = {};
    for my $key ( keys %{$defaults} ) {
        $parms->{$key} =
            exists $passed_parms{$key}
                ? delete $passed_parms{$key}
                : $defaults->{$key};
    }

    # Any leftover keys are bogus
    for my $badkey ( keys %passed_parms ) {
        my $sub = (caller(1))[3];
        $parms->{error_handler}->( "Invalid option passed to $sub(): $badkey" );
    }

    # If it's not a code ref, assume standard sort
    if ( $parms->{sort_files} && ( ref($parms->{sort_files}) ne 'CODE' ) ) {
        $parms->{sort_files} = \&sort_standard;
    }
    my @queue;

    for ( @_ ) {
        my $start = reslash( $_ );
        if (-d $start) {
            push @queue, ($start,undef,$start);
        }
        else {
            push @queue, (undef,$start,$start);
        }
    }

    return ($parms,@queue);
}

=head2 _candidate_files( $parms, $dir )

Pulls out the files/dirs that might be worth looking into in I<$dir>.
If I<$dir> is the empty string, then search the current directory.

I<$parms> is the hashref of parms passed into File::Next constructor.

=cut

sub _candidate_files {
    my $parms   = shift;
    my $dirname = shift;

    my $dh;
    if ( !opendir $dh, $dirname ) {
        $parms->{error_handler}->( "$dirname: $!", $! + 0 );
        return;
    }

    my @newfiles;
    my $descend_filter = $parms->{descend_filter};
    my $follow_symlinks = $parms->{follow_symlinks};
    my $sort_sub = $parms->{sort_files};

    for my $file ( grep { !exists $skip_dirs{$_} } readdir $dh ) {
        my $has_stat;

        my $fullpath = File::Spec->catdir( $dirname, $file );
        if ( !$follow_symlinks ) {
            next if -l $fullpath;
            $has_stat = 1;
        }

        # Only do directory checking if we have a descend_filter
        if ( $descend_filter ) {
            if ( $has_stat ? (-d _) : (-d $fullpath) ) {
                local $File::Next::dir = $fullpath;
                local $_ = $file;
                next if not $descend_filter->();
            }
        }
        if ( $sort_sub ) {
            push( @newfiles, [ $dirname, $file, $fullpath ] );
        }
        else {
            push( @newfiles, $dirname, $file, $fullpath );
        }
    }
    closedir $dh;

    if ( $sort_sub ) {
        return map { @{$_} } sort $sort_sub @newfiles;
    }

    return @newfiles;
}

=head1 DIAGNOSTICS

=over

=item C<< File::Next::files must not be invoked as File::Next->files >>

=item C<< File::Next::dirs must not be invoked as File::Next->dirs >>

=item C<< File::Next::everything must not be invoked as File::Next->everything >>

=back

The interface functions do not allow for the method invocation syntax and
throw errors with the messages above. You can work around this limitation
with L.

    for my $file_system_feature (qw(dirs files)) {
        my $iterator = File::Next->can($file_system_feature)->($options, $target_directory);
        while (defined(my $name = $iterator->())) {
            # ...
        }
    }

=head1 SPEED TWEAKS

=over 4

=item * Don't set C<< follow_symlinks => 0 >> unless you need it.

=back

=head1 AUTHOR

Andy Lester, C<<  >>

=head1 BUGS

Please report any bugs or feature requests to
L.

Note that File::Next does NOT use L for bug tracking.

=head1 SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc File::Next

You can also look for information at:

=over 4

=item * File::Next's bug queue

L

=item * AnnoCPAN: Annotated CPAN documentation

L

=item * CPAN Ratings

L

=item * Search CPAN

L

=item * Source code repository

L

=back

=head1 ACKNOWLEDGEMENTS

All file-finding in this module is adapted from Mark Jason Dominus'
marvelous I, page 126.

Thanks also for bug fixes and typo finding to
Gerhard Poul,
Brian Fraser,
Todd Rinaldo,
Bruce Woodward,
Christopher J. Madsen,
Bernhard Fisseni
and Rob Hoelz.

=head1 COPYRIGHT & LICENSE

Copyright 2005-2016 Andy Lester.

This program is free software; you can redistribute it and/or modify
it under the terms of the Artistic License version 2.0.

=cut

1; # End of File::Next