File Coverage

blib/lib/File/DesktopEntry.pm

Criterion	Covered	Total	%
statement	269	282	95.3
branch	131	172	76.1
condition	39	61	63.9
subroutine	39	39	100.0
pod	17	17	100.0
total	495	571	86.6

package File::DesktopEntry;

use strict;
use warnings;

use vars qw/$AUTOLOAD/;
use Carp;
use Encode;
use File::Spec;
use File::BaseDir 0.03 qw/data_files data_home/;
use URI::Escape;

our $VERSION = '0.22';
our $VERBOSE = 0;

if ($^O eq 'MSWin32') {
    eval q/use Win32::Process/;
    die $@ if $@;
}

=head1 NAME

File::DesktopEntry - Object to handle .desktop files

=head1 SYNOPSIS

    use File::DesktopEntry;

    my $entry = File::DesktopEntry->new('firefox');

    print "Using ".$entry->Name." to open http://perl.org\n";
    $entry->run('http://perl.org');

=head1 DESCRIPTION

This module is designed to work with F<.desktop> files. The format of these files
is specified by the freedesktop "Desktop Entry" specification. This module can
parse these files but also knows how to run the applications defined by these
files.

For this module version 1.0 of the specification was used.

This module was written to support L.

Please remember: case is significant for the names of Desktop Entry keys.

=head1 VARIABLES

You can set the global variable C<$File::DesktopEntry::VERBOSE>. If set the
module prints a warning every time a command gets executed.

The global variable C<$File::DesktopEntry::LOCALE> tells you what the default
locale being used is. However, changing it will not change the default locale.

=head1 AUTOLOAD

All methods that start with a capital are autoloaded as C where
key is the autoloaded method name.

=head1 METHODS

=over 4

=item C

=item C

=item C

Constructor. FILE, NAME or TEXT are optional arguments.

When a name is given (a string without 'C', 'C<\>' or 'C<.>') a lookup is
done using File::BaseDir. If the file found in this lookup is not writable or
if no file was found, the XDG_DATA_HOME path will be used when writing.

=cut

our $LOCALE = 'C';

# POSIX setlocale(LC_MESSAGES) not supported on all platforms
# so we do it ourselves ...
# string might look like lang_COUNTRY.ENCODING@MODIFIER
for (qw/LC_ALL LC_MESSAGES LANGUAGE LANG/) {
    next unless $ENV{$_};
    $LOCALE = $ENV{$_};
    last;
}
our $_locale = _parse_lang($LOCALE);

sub new {
    my ($class, $file) = @_;
    my $self = bless {}, $class;
    if (! defined $file) { # initialize new file
        $self->set(Version => '1.0', Encoding => 'UTF-8');
    }
    elsif (ref $file)           { $self->read($file)   } # SCALAR
    elsif ($file =~ /[\/\\\.]/) { $$self{file} = $file } # file
    else {
        $$self{file} = $class->lookup($file);     # name
        $$self{name} = $file;
    }
    return $self;
}

sub AUTOLOAD {
    $AUTOLOAD =~ s/.*:://;
    return if $AUTOLOAD eq 'DESTROY';
    croak "No such method: File::DesktopEntry::$AUTOLOAD"
        unless $AUTOLOAD =~ /^[A-Z][A-Za-z0-9-]+$/;
    return $_[0]->get($AUTOLOAD);
}

=item C

Returns a filename for a desktop entry with desktop file id NAME.

=cut

sub lookup {
    my (undef, $name) = @_;
    $name .= '.desktop';
    my $file = data_files('applications', $name);
    if (! $file and $name =~ /-/) {
        # name contains "-" and was not found
        my @name = split /-/, $name;
        $file = data_files('applications', @name);
    }
    return $file;
}

sub _parse_lang {
    # lang might look like lang_COUNTRY.ENCODING@MODIFIER
    my $lang = shift;
    return '' if !$lang or $lang eq 'C' or $lang eq 'POSIX';
    $lang =~ m{^
        ([^_@\.]+)        # lang       $1
        (?: _  ([^@\.]+) )?    # COUNTRY  $2
        (?: \.  [^@]+    )?    # ENCODING
        (?: \@ (.+)      )?    # MODIFIER $3
    $}x or return '';
    my ($l, $c, $m) = ($1, $2, $3);
    my @locale = (
        $l,
        ($m         ? "$l\@$m"     : ()),
        ($c         ? "$l\_$c"     : ()),
        (($m && $c) ? "$l\_$c\@$m" : ())  );
    return join '|', reverse @locale;
}

=item C

Returns true if the Exec string for this desktop entry specifies that the
application uses URIs instead of paths. This can be used to determine
whether an application uses a VFS library.

=item C

Returns true if the Exec string for this desktop entry specifies that the
application can handle multiple arguments at once.

=cut


sub wants_uris {
    my $self = shift;
    my $exec = $self->get('Exec');
    croak "No Exec string defined for desktop entry" unless length $exec;
    $exec =~ s/\%\%//g;
    return $exec =~ /\%U/i;
}

sub wants_list {
    my $self = shift;
    my $exec = $self->get('Exec');
    croak "No Exec string defined for desktop entry" unless length $exec;
    $exec =~ s/\%\%//g;
    return $exec !~ /\%[fud]/; # we default to %F if no /\%[FUD]/i is found
}

=item C

Forks and runs the application specified in this Desktop Entry
with arguments FILES as a background process. Returns the pid.

The child process fails when this is not a Desktop Entry of type Application
or if the Exec key is missing or invalid.

If the desktop entry specifies that the program needs to be executed in a
terminal the $TERMINAL environment variable is used. If this variable is not
set C is used as default.

(On Windows this method returns a L object.)

=item C

Like C but using the C system call.
It only return after the application has ended.

=item C

Like C but using the C system call. This method
is expected not to return but to replace the current process with the
application you try to run.

On Windows this method doesn't always work the way you want it to
due to the C emulation on this platform. Try using C or
C instead.

=cut

sub run {
    my $pid = fork;
    return $pid if $pid; # parent process
    unshift @_, 'exec'; goto \&_run;
}

sub system { unshift @_, 'system'; goto \&_run }

sub exec   { unshift @_, 'exec';   goto \&_run }

sub _run {
    my $call = shift;
    my $self = shift;

    croak "Desktop entry is not an Application"
        unless $self->get('Type') eq 'Application';

    my @exec = $self->parse_Exec(@_);

    my $t = $self->get('Terminal');
    if ($t and $t eq 'true') {
        my $term = $ENV{TERMINAL} || 'xterm -e';
        unshift @exec, _split($term);
    }

    my $cwd;
    if (my $path = $self->get('Path')) {
        require Cwd;
        $cwd = Cwd::getcwd();
        chdir $path or croak "Could not change to dir: $path";
        $ENV{PWD} = $path;
        warn "Running from directory: $path\n" if $VERBOSE;
    }

    warn "Running: "._quote(@exec)."\n" if $VERBOSE;

    if ($call eq 'exec') { CORE::exec   {$exec[0]} @exec; exit 1 }
    else                 { CORE::system {$exec[0]} @exec         }
    warn "Error: $!\n" if $VERBOSE and $?;

    if (defined $cwd) {
        chdir $cwd or croak "Could not change back to dir: $cwd";
        $ENV{PWD} = $cwd;
    }
}

=item C

Expands the Exec format in this desktop entry with. Returns a properly quoted
string in scalar context or a list of words in list context. Dies when the
Exec key is invalid.

It supports the following fields:

    %f    single file
    %F    multiple files
    %u    single url
    %U    multiple urls
    %i    Icon field prefixed by --icon
    %c    Name field, possibly translated
    %k    location of this .desktop file
    %%    literal '%'

If necessary this method tries to convert between paths and URLs but this
is not perfect.

Fields that are deprecated, but (still) supported by this module:

    %d    single directory
    %D    multiple directories

The fields C<%n>, C<%N>, C<%v> and C<%m> are deprecated and will cause a
warning if C<$VERBOSE> is used. Any other unknown fields will cause an error.

The fields C<%F>, C<%U>, C<%D> and C<%i> can only occur as separate words
because they expand to multiple arguments.

Also see L.

=cut

sub parse_Exec {
    my ($self, @argv) = @_;
    my @format = _split( $self->get('Exec') );

    # Check format
    my $seen = 0;
    for (@format) {
        my $s = $_; # copy;
        $s =~ s/\%\%//g;
        $seen += ($s =~ /\%[fFuUdD]/);

        die "Exec key for '".$self->get('Name')."' contains " .
            "'\%F\', '\%U' or '\%D' at the wrong place\n"
            if $s !~ /^\%[FUD]$/ and $s =~ /\%[FUD]/;

        die "Exec key for '".$self->get('Name')."' contains " .
            "unknown field code '$1'\n"
            if $s =~ /(\%[^fFuUdDnNickvm])/;

        croak "Application '".$self->get('Name')."' ".
              "takes only one argument"
            if @argv > 1 and $s =~ /\%[fud]/;

        warn "Exec key for '".$self->get('Name')."' contains " .
             "deprecated field codes\n"
            if $VERBOSE and $s =~ /%([nNvm])/;
    }
    if    ($seen == 0) { push @format, '%F' }
    elsif ($seen >  1) {
        # not allowed according to the spec
        warn "Exec key for '".$self->get('Name')."' contains " .
             "multiple fields for files or uris.\n"
    }

    # Expand format
    my @exec;

    for (@format) {
        if (/^\%([FUD])$/) {
            push @exec,
                ($1 eq 'F') ? _paths(@argv) :
                ($1 eq 'U') ? _uris(@argv)  : _dirs(@argv)  ;
        }
        elsif ($_ eq '%i') {
            my $icon = $self->get('Icon');
            push @exec, '--icon', $icon if defined($icon);
        }
        else { # expand with word ( e.g. --input=%f )
            my $bad;
            s/\%(.)/
                ($1 eq '%') ? '%'                :
                ($1 eq 'f') ? (_paths(@argv))[0] :
                ($1 eq 'u') ? (_uris(@argv) )[0] :
                ($1 eq 'd') ? (_dirs(@argv) )[0] :
                ($1 eq 'c') ? $self->get('Name') :
                ($1 eq 'k') ? $$self{file}       : '' ;
            /eg;

            push @exec, $_;
        }
    }

    if (wantarray and $^O eq 'MSWin32') {
        # Win32 requires different quoting *sigh*
        for (grep /"/, @exec) {
                s#"#\\"#g;
                $_ = qq#"$_"#;
        }
    }
    return wantarray ? (@exec) : _quote(@exec);
}

sub _split {
    # Reverse quoting and break string in words.
    # It allows single quotes to be used, which the spec doesn't.
    my $string = shift;
    my @args;
    while ($string =~ /\S/) {
        if ($string =~ /^(['"])/) {
            my $q = $1;
            $string =~ s/^($q(\\.|[^$q])*$q)//s;
            push @args, $1 if defined $1;
        }
        $string =~ s/(\S*)\s*//; # also fallback for above regex
        push @args, $1 if defined $1;
    }
    @args = grep length($_), @args;
    for (@args) {
        if (/^(["'])(.*)\1$/s) {
            $_ = $2;
            s/\\(["`\$\\])/$1/g; # remove backslashes
        }
    }
    return @args;
}

sub _quote {
    # Turn a list of words in a properly quoted Exec key
    my @words = @_; # copy;
    return join ' ', map {
        if (/([\s"'`\\<>~\|\&;\$\*\?#\(\)])/) { # reserved chars
            s/(["`\$\\])/\\$1/g; # add backslashes
            $_ = qq/"$_"/;       # add quotes
        }
        $_;
    } grep defined($_), @words;
}

sub _paths {
    # Check if we need to convert file:// uris to paths
    # support file:/path file://localhost/path and file:///path
    # A path like file://host/path is replace by smb://host/path
    # which the app probably can't open
    map {
        $_ = _uri_to_path($_) if s#^file:(?://localhost/+|/|///+)(?!/)#/#i;
        s#^file://(?!/)#smb://#i;
        $_;
    } @_;
}

sub _dirs {
    # Like _paths, but makes the path a directory
    map {
        if (-d $_) { $_ }
        else {
            my ($vol, $dirs, undef) = File::Spec->splitpath($_);
            File::Spec->catpath($vol, $dirs, '');
        }
    } _paths(@_);
}

sub _uris {
    # Convert paths to file:// uris
    map {
        m#^\w+://# ? $_ : 'file://'._path_to_uri($_);
    } @_;
}

sub _uri_to_path {
    my $x = Encode::encode('utf8', $_);
    $x = uri_unescape($x);
    return Encode::decode('utf8', $x);
}

sub _path_to_uri {
    my $path = File::Spec->rel2abs(shift);
    my ($volume, $directories, $file) = File::Spec->splitpath($path);
    my $uri = '';

    # actually, on Windows, File URIs look like this:
    # file:///C:/Program%20Files/MyApp/app.exe
    # ref: https://blogs.msdn.microsoft.com/ie/2006/12/06/file-uris-in-windows/
    if ($volume) {
        $uri .= '/' . $volume;
    }
    $uri .= join '/', map { uri_escape_utf8($_) } File::Spec->splitdir($directories . $file);
    return $uri;
}

=item C

=item C

Get a value for KEY from GROUP. If GROUP is not specified 'Desktop Entry' is
used. All values are treated as string, so e.g. booleans will be returned as
the literal strings "true" and "false".

When KEY does not contain a language code you get the translation in the
current locale if available or a sensible default. The request a specific
language you can add the language part. E.g. C<< $entry->get('Name[nl_NL]') >>
can return either the value of the 'Name[nl_NL]', the 'Name[nl]' or the 'Name'
key in the Desktop Entry file. Exact language parsing order can be found in the
spec. To force you get the untranslated key use either 'Name[C]' or
'Name[POSIX]'.

=cut

# used for (un-)escaping strings
my %Chr = (s => ' ', n => "\n", r => "\r", t => "\t", '\\' => '\\');
my %Esc = reverse %Chr;

sub get {
    my ($self, $group, $key) =
        (@_ == 2) ? ($_[0], '', $_[1]) : (@_) ;
    my $locale = $_locale;
    if ($key =~ /^(.*?)\[(.*?)\]$/) {
        $key = $1;
        $locale = _parse_lang($2);
    }

    my @lang = split /\|/, $locale;

    # Get values that match locale from group
    $self->read() unless $$self{groups};
    my $i = $self->_group($group);
    return undef unless defined $i;
    my $lang = join('|', map quotemeta($_), @lang) || 'C';
    my %matches = ( $$self{groups}[$i] =~
        /^(\Q$key\E\[(?:$lang)\]|\Q$key\E)[^\S\n]*=[^\S\n]*(.*?)\s*$/gm );
    return undef unless keys %matches;

    # Find preferred value
    my @keys = (map($key."[$_]", @lang), $key);
    my ($value) = grep defined($_), @matches{@keys};

    # Parse string (replace \n, \t, etc.)
    $value =~ s/\\(.)/$Chr{$1}||$1/eg;
    return $value;
}

sub _group { # returns index for a group name
    my ($self, $group, $dont_die) = @_;
    $group ||= 'Desktop Entry';
    croak "Group name contains invalid characters: $group"
        if $group =~ /[\[\]\r\n]/;
    for my $i (0 .. $#{$$self{groups}}) {
        return $i if $$self{groups}[$i] =~ /^\[\Q$group\E\]/;
    }
    return undef;
}

=item C VALUE, ...)>

=item C VALUE, ...)>

Set values for one or more keys. If GROUP is not given "Desktop Entry" is used.
All values are treated as strings, backslashes, newlines and tabs are escaped.
To set a boolean key you need to use the literal strings "true" and "false".

Unlike the C call languages are not handled automatically for C.
KEY should include the language part if you want to set a translation.
E.g. C<< $entry->set("Name[nl_NL]" => "Tekst Verwerker") >> will set a Dutch
translation for the Name key. Using either "Name[C]" or "Name[POSIX]" will
be equivalent with not giving a language argument.

When setting the Exec key without specifying a group it will be parsed
and quoted correctly as required by the spec. You can use quoted arguments
to include whitespace in a argument, escaping whitespace does not work.
To circumvent this quoting explicitly give the group name 'Desktop Entry'.

=cut

sub set {
    my $self = shift;
    my ($group, @data) = ($#_ % 2) ? (undef, @_) : (@_) ;

    $self->read() unless $$self{groups} or ! $$self{file};
    my $i = $self->_group($group);
    unless (defined $i) {
        $group ||= 'Desktop Entry';
        push @{$$self{groups}}, "[$group]\n";
        $i = $#{$$self{groups}};
    }

    while (@data) {
        my ($k, $v) = splice(@data, 0, 2);
        $k =~ s/\[(C|POSIX)\]$//;  # remove default locale
        my ($word) = ($k =~ /^(.*?)(\[.*?\])?$/);
            # separate key and locale
        croak "BUG: Key missing: $k" unless length $word;
        carp "Key contains invalid characters: $k"
            if $word =~ /[^A-Za-z0-9-]/;
        $v = _quote( _split($v) ) if ! $group and $k eq 'Exec';
            # Exec key needs extra quoting
        $v =~ s/([\\\n\r\t])/\\$Esc{$1}/g; # add escapes
        $$self{groups}[$i] =~ s/^\Q$k\E=.*$/$k=$v/m and next;
        $$self{groups}[$i] .= "$k=$v\n";
    }
}

=item C

Returns the (modified) text of the file.

=cut

sub text {
    $_[0]->read() unless $_[0]{groups};
    return '' unless $_[0]{groups};
    s/\n?$/\n/ for @{$_[0]{groups}}; # just to be sure
    return join "\n", @{$_[0]{groups}};
}

=item C

=item C

Read Desktop Entry data from file or memory buffer.
Without argument defaults to file given at constructor.

If you gave a file, text buffer or name to the constructor this method will
be called automatically.

=item C

Read Desktop Entry data from filehandle or IO object.

=cut

sub read {
    my ($self, $file) = @_;
    $file ||= $$self{file};
    croak "DesktopEntry has no filename to read from" unless length $file;

    my $fh;
    unless (ref $file)  {
        open $fh, "<$file" or croak "Could not open file: $file";
    }
    else {
        open $fh, '<', $file or croak "Could not open SCALAR ref !?";
    }
    binmode $fh, ':utf8';
    $self->read_fh($fh);
    close $fh;
}

sub read_fh {
    my ($self, $fh) = @_;
    $$self{groups} = [];

    # Read groups
    my $group = '';
    while (my $l = <$fh>) {
        $l =~ s/\r?\n$/\n/; # DOS to Unix conversion
        if ($l =~ /^\[(.*?)\]\s*$/) {
            push @{$$self{groups}}, $group
                if length $group;
            $group = '';
        }
        $group .= $l;
    }
    push @{$$self{groups}}, $group;
    s/\n\n$/\n/ for @{$$self{groups}}; # remove last empty line

    # Some checks
    for (qw/Name Type/) {
        carp "Required key missing in Desktop Entry: $_"
            unless defined $self->get($_);
    }
    my $enc = $self->get('Encoding');
    carp "Desktop Entry uses unsupported encoding: $enc"
        if $enc and $enc ne 'UTF-8';
}

=item C

Write the Desktop Entry data to FILE. Without arguments it writes to
the filename given to the constructor if any.

The keys Name and Type are required. Type can be either C,
C or C. For an application set the optional key C. For
a link set the C key.

=cut

# Officially we should check lines end with LF - this is \n on Unix
# but on Windows \n is CR LF, which breaks the spec

sub write {
    my $self = shift;
    my $file = shift || $$self{file};
    unless ($$self{groups}) {
        if ($$self{file}) { $self->read() }
        else { croak "Can not write empty Desktop Entry file" }
    }

    # Check keys
    for (qw/Name Type/) {
        croak "Can not write a desktop file without a $_ field"
            unless defined $self->get($_);
    }
    $self->set(Version => '1.0', Encoding => 'UTF-8');

    # Check file writable
    $file = $self->_data_home_file
        if (! $file or ! -w $file) and defined $$self{name};
    croak "No file given for writing Desktop Entry" unless length $file;

    # Write file
    s/\n?$/\n/ for @{$$self{groups}}; # just to be sure
    open OUT, ">$file" or die "Could not write file: $file\n";
    binmode OUT, ':utf8' unless $] < 5.008;
    print OUT join "\n", @{$$self{groups}};
    close OUT;
}

sub _data_home_file {
    # create new file name in XDG_DATA_HOME from name
    my $self = shift;
    my @parts = split /-/, $$self{name};
    $parts[-1] .= '.desktop';
    my $dir = data_home('applications', @parts[0 .. $#parts-1]);
    unless (-d $dir) { # create dir if it doesn't exist
        require File::Path;
        File::Path::mkpath($dir);
    }
    return data_home('applications', @parts);
}

=back

=head2 Backwards Compatibility

Methods supported for backwards compatibility with 0.02.

=over 4

=item C

Alias for C.

=item C

Alias for C.

=item C

Identical to C.
LANG defaults to 'C', GROUP is optional.

=cut

sub new_from_file { $_[0]->new($_[1])  }

sub new_from_data { $_[0]->new(\$_[1]) }

sub get_value {
    my ($self, $key, $group, $locale) = @_;
    $locale ||= 'C';
    $key .= "[$locale]";
    $group ? $self->get($group, $key) : $self->get($key);
}

=back

=head1 NON-UNIX PLATFORMS

This module has a few bits of code to make it work on Windows. It handles
C uri a bit different and it uses L. On other
platforms your mileage may vary.

Please note that the specification is targeting Unix platforms only and
will only have limited relevance on other platforms. Any platform-dependent
behavior in this module should be considered an extension of the spec.

=cut

if ($^O eq 'MSWin32') {
    # Re-define some modules - I assume this block gets optimized away by the
    # interpreter when not running on windows.
    no warnings;

    # Wrap _paths() to remove first '/'
    # As a special case translate SMB file:// uris
    my $_paths = \&_paths;
    *_paths = sub {
        my @paths = map {
            s#^file:////(?!/)#smb://#;
            $_;
        } @_;
        map {
            s#^/+([a-z]:/)#$1#i;
            $_;
        } &$_paths(@paths);
    };

    # Wrap _uris() to remove '\' in path
    my $_uris = \&_uris;
    *_uris = sub {
        map {
            s#\\#/#g;
            $_;
        } &$_uris(@_);
    };

    # Using Win32::Process because fork is not native on win32
    # Effect is that closing an application spawned with fork
    # can kill the parent process as well when using Gtk2
    *run = sub {
        my ($self, @files) = @_;

        my $cmd = eval { $self->parse_Exec(@files) };
        warn $@ if $@; # run should not die

        my $bin = (_split($cmd))[0];
        unless (-f $bin) { # we need the real binary path
            my ($b) = grep {-f $_}
                     map File::Spec->catfile($_, $bin),
                     split /[:;]/, $ENV{PATH} ;
            if (-f $b) { $bin = $b }
            else {
                warn "Could not find application: $bin\n";
                return;
            }
        }

        my $dir = $self->get('Path') || '.';

        if ($VERBOSE) {
                warn "Running from directory: $dir" unless $dir eq '.';
                warn "Running: $cmd\n";
        }
        my $obj;
        eval {
            Win32::Process::Create(
                $obj, $bin, $cmd, 0, &NORMAL_PRIORITY_CLASS, $dir );
        };
        warn $@ if $@;
        return $obj;
    };

}

1;

__END__