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lib/App/MtAws/Utils.pm  view on Meta::CPAN

=head1 open_file(my $f, $filename, %args)

$args{mode} - mode to open, <, > or >>
$args{use_filename_encoding} - (TRUE) - encode to binary string, (FALSE) - don't tocuh (already a binary string). Default TRUE
$args{file_encoding} or $args{binary} - file content encoding or it's a binary file (mutual exclusive)
$args{not_empty} - assert that file is not empty after open

Assertions made (using "confess"):

1) Bad arguments (programmer's error)
2) File is not a plain file
3) File is not a plain file, but after open (race conditions)
4) File is empty and not_empty specified
5) File is empty and not_empty specified, but after open (race conditions)

NOTE: If you want exceptions for (2) and (4) - check it before open_file. And additional checks inside open_file will
prevent race conditions

=cut

sub open_file($$%)
{
	(undef, my $filename, my %args) = @_;
	%args = (use_filename_encoding => 1, %args);
	my $original_filename = $filename;

	my %checkargs = %args;
	defined $checkargs{$_} && delete $checkargs{$_} for qw/use_filename_encoding mode file_encoding not_empty binary/;
	confess "Unknown argument(s) to open_file: ".join(';', keys %checkargs) if %checkargs;

	confess 'Argument "mode" is required' unless defined($args{mode});
	confess "unknown mode $args{mode}" unless $args{mode} =~ m!^\+?(<|>>?)$!;
	my $mode = $args{mode};

	confess "not_empty can be used in read mode only"
		if ($args{not_empty} && $args{mode} ne '<');


	if (defined($args{file_encoding})) {
		$mode .= ":encoding($args{file_encoding})";
		confess "cannot use binary and file_encoding at same time'" if $args{binary};
	} elsif (!$args{binary}) {
		confess "there should be file encoding or 'binary'";
	}

	if ($args{use_filename_encoding}) {
		$filename = binaryfilename $filename;
	}

	confess "File is not a plain file" if -e $filename && (! -f $filename);
	confess "File should not be empty" if $args{not_empty} && (! -s $filename);

	open ($_[0], $mode, $filename) or return;
	my $f = $_[0];

	confess unless -f $f; # check for race condition - it was a file when we last checked, but now it's a directory
	confess if $args{not_empty} && (! -s $f);

	binmode $f if $args{binary};

	return $f;
}

sub file_size($%)
{
	my $filename = shift;
	my (%args) = (use_filename_encoding => 1, @_);
	if ($args{use_filename_encoding}) {
		$filename = binaryfilename $filename;
	}
	confess "file not exists" unless -f $filename;
	return -s $filename;
}

sub file_exists($%)
{
	my $filename = shift;
	my (%args) = (use_filename_encoding => 1, @_);
	if ($args{use_filename_encoding}) {
		$filename = binaryfilename $filename;
	}
	return -f $filename;
}

sub file_mtime($%)
{
	my $filename = shift;
	my (%args) = (use_filename_encoding => 1, @_);
	if ($args{use_filename_encoding}) {
		$filename = binaryfilename $filename;
	}
	confess "file not exists" unless -f $filename;
	return stat($filename)->mtime;
}

# TODO: test
sub file_inodev($%)
{
	my $filename = shift;
	my (%args) = (use_filename_encoding => 1, @_);
	if ($args{use_filename_encoding}) {
		$filename = binaryfilename $filename;
	}
	confess "file not exists" unless -e $filename;
	my $s = stat($filename);
	$s->dev."-".$s->ino;
}

sub is_wide_string
{
	defined($_[0]) && utf8::is_utf8($_[0]) && (bytes::length($_[0]) != length($_[0]))
}

# if we have ASCII-only data, let's drop UTF-8 flag in order to optimize some regexp stuff
# TODO: write also version which does not check is_utf8 - it's faster when utf8 always set
sub try_drop_utf8_flag
{
	Encode::_utf8_off($_[0]) if utf8::is_utf8($_[0]) && (bytes::length($_[0]) == length($_[0]));
}