Implement the GET_VERSION request (with a fallback to i3 --version)

lib/AnyEvent/I3.pm

@@ -94,10 +94,11 @@ use constant TYPE_GET_OUTPUTS => 3;
 use constant TYPE_GET_TREE => 4;
 use constant TYPE_GET_MARKS => 5;
 use constant TYPE_GET_BAR_CONFIG => 6;
+use constant TYPE_GET_VERSION => 7;
 
 our %EXPORT_TAGS = ( 'all' => [
     qw(i3 TYPE_COMMAND TYPE_GET_WORKSPACES TYPE_SUBSCRIBE TYPE_GET_OUTPUTS
-       TYPE_GET_TREE TYPE_GET_MARKS TYPE_GET_BAR_CONFIG)
+       TYPE_GET_TREE TYPE_GET_MARKS TYPE_GET_BAR_CONFIG TYPE_GET_VERSION)
 ] );
 
 our @EXPORT_OK = ( @{ $EXPORT_TAGS{all} } );
@@ -116,20 +117,10 @@ sub i3 {
     AnyEvent::I3->new(@_)
 }
 
-=head2 $i3 = AnyEvent::I3->new([ $path ])
+# Calls i3, even when running in taint mode.
+sub _call_i3 {
+    my ($args) = @_;
 
-Creates a new C<AnyEvent::I3> object and returns it.
-
-C<path> is an optional path of the UNIX socket to connect to. It is strongly
-advised to NOT specify this unless you're absolutely sure you need it.
-C<AnyEvent::I3> will automatically figure it out by querying the running i3
-instance on the current DISPLAY which is almost always what you want.
-
-=cut
-sub new {
-    my ($class, $path) = @_;
-
-    if (!$path) {
     my $path_tainted = tainted($ENV{PATH});
     # This effectively circumvents taint mode checking for $ENV{PATH}. We
     # do this because users might specify PATH explicitly to call i3 in a
@@ -152,16 +143,32 @@ sub new {
     }
     # Otherwise the qx() operator wont work:
     delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
-        chomp($path = qx(i3 --get-socketpath));
+    chomp(my $result = qx(i3 $args));
     # Circumventing taint mode again: the socket can be anywhere on the
     # system and that’s okay.
-        if ($path =~ /^([^\0]+)$/) {
-            $path = $1;
-        } else {
-            warn "Asking i3 for the socket path failed. Is DISPLAY set and is i3 in your PATH?";
-        }
+    if ($result =~ /^([^\0]+)$/) {
+        return $1;
     }
 
+    warn "Calling i3 $args failed. Is DISPLAY set and is i3 in your PATH?";
+    return undef;
+}
+
+=head2 $i3 = AnyEvent::I3->new([ $path ])
+
+Creates a new C<AnyEvent::I3> object and returns it.
+
+C<path> is an optional path of the UNIX socket to connect to. It is strongly
+advised to NOT specify this unless you're absolutely sure you need it.
+C<AnyEvent::I3> will automatically figure it out by querying the running i3
+instance on the current DISPLAY which is almost always what you want.
+
+=cut
+sub new {
+    my ($class, $path) = @_;
+
+    $path = _call_i3('--get-socketpath') unless $path;
+
     # This is the old default path (v3.*). This fallback line can be removed in
     # a year from now. -- Michael, 2012-07-09
     $path ||= '~/.i3/ipc.sock';
@@ -441,6 +448,54 @@ sub get_bar_config {
     $self->message(TYPE_GET_BAR_CONFIG, $id)
 }
 
+=head2 get_version
+
+Gets the i3 version via IPC, with a fall-back that parses the output of i3
+--version (for i3 < v4.3).
+
+    my $version = i3->get_version()->recv;
+    say "major: " . $version->{major} . ", minor = " . $version->{minor};
+
+=cut
+sub get_version {
+    my ($self) = @_;
+
+    $self->_ensure_connection;
+
+    my $cv = AnyEvent->condvar;
+
+    my $version_cv = $self->message(TYPE_GET_VERSION);
+    my $timeout;
+    $timeout = AnyEvent->timer(
+        after => 1,
+        cb => sub {
+            warn "Falling back to i3 --version since the running i3 doesn’t support GET_VERSION yet.";
+            my $version = _call_i3('--version');
+            $version =~ s/^i3 version //;
+            my $patch = 0;
+            my ($major, $minor) = ($version =~ /^([0-9]+)\.([0-9]+)/);
+            if ($version =~ /^[0-9]+\.[0-9]+\.([0-9]+)/) {
+                $patch = $1;
+            }
+            # Strip everything from the © sign on.
+            $version =~ s/ ©.*$//g;
+            $cv->send({
+                major => int($major),
+                minor => int($minor),
+                patch => int($patch),
+                human_readable => $version,
+            });
+            undef $timeout;
+        },
+    );
+    $version_cv->cb(sub {
+        undef $timeout;
+        $cv->send($version_cv->recv);
+    });
+
+    return $cv;
+}
+
 =head2 command($content)
 
 Makes i3 execute the given command