command: allow targeting outputs by name

This extends focus-output and send-to-output to allow targeting
outputs by name instead of relative position.

river/command.zig

@@ -99,6 +99,7 @@ pub const Error = error{
     InvalidCharacter,
     InvalidDirection,
     InvalidPhysicalDirection,
+    InvalidOutputIndicator,
     InvalidOrientation,
     InvalidRgba,
     InvalidValue,
@@ -141,6 +142,7 @@ pub fn errToMsg(err: Error) [:0]const u8 {
         Error.InvalidCharacter => "invalid character in argument",
         Error.InvalidDirection => "invalid direction. Must be 'next' or 'previous'",
         Error.InvalidPhysicalDirection => "invalid direction. Must be 'up', 'down', 'left' or 'right'",
+        Error.InvalidOutputIndicator => "invalid indicator for an output. Must be 'next', 'previous', 'up', 'down', 'left', 'right' or a valid output name",
         Error.InvalidOrientation => "invalid orientation. Must be 'horizontal', or 'vertical'",
         Error.InvalidRgba => "invalid color format, must be hexadecimal 0xRRGGBB or 0xRRGGBBAA",
         Error.InvalidValue => "invalid value",

river/command/output.zig

@@ -63,6 +63,8 @@ pub fn sendToOutput(
 
     if (seat.focused == .view) {
         const destination_output = (try getOutput(seat, args[1])) orelse return;
+        // If the view is already on destination_output, do nothing
+        if (seat.focused.view.output == destination_output) return;
         seat.focused.view.sendToOutput(destination_output);
 
         // Handle the change and focus whatever's next in the focus stack
@@ -93,6 +95,13 @@ fn getOutput(seat: *Seat, str: []const u8) !?*Output {
         ) orelse return null;
         return @intToPtr(*Output, wlr_output.data);
     } else {
-        return Error.InvalidDirection;
+        // Check if an output matches by name
+        var it = server.root.outputs.first;
+        while (it) |node| : (it = node.next) {
+            if (std.mem.eql(u8, std.mem.span(node.data.wlr_output.name), str)) {
+                return &node.data;
+            }
+        }
+        return Error.InvalidOutputIndicator;
     }
 }