implement device status request

src/Window.zig

@@ -644,3 +644,28 @@ pub fn deviceAttributes(
         else => log.warn("unimplemented device attributes req: {}", .{req}),
     }
 }
+
+pub fn deviceStatusReport(
+    self: *Window,
+    req: terminal.DeviceStatusReq,
+) !void {
+    switch (req) {
+        .operating_status => self.queueWrite("\x1B[0n") catch |err|
+            log.warn("error queueing device attr response: {}", .{err}),
+
+        .cursor_position => {
+            // Response always is at least 4 chars, so this leaves the
+            // remainder for the row/column as base-10 numbers. This
+            // will support a very large terminal.
+            var buf: [32]u8 = undefined;
+            const resp = try std.fmt.bufPrint(&buf, "\x1B[{};{}R", .{
+                self.terminal.cursor.y + 1,
+                self.terminal.cursor.x + 1,
+            });
+
+            try self.queueWrite(resp);
+        },
+
+        else => log.warn("unimplemented device status req: {}", .{req}),
+    }
+}

src/terminal/ansi.zig

@@ -49,3 +49,12 @@ pub const DeviceAttributeReq = enum {
     secondary, // >
     tertiary, // =
 };
+
+/// The device status request type (ESC [ n).
+pub const DeviceStatusReq = enum(u16) {
+    operating_status = 5,
+    cursor_position = 6,
+
+    // Non-exhaustive so that @intToEnum never fails for unsupported modes.
+    _,
+};

src/terminal/main.zig

@@ -7,6 +7,7 @@ pub const Terminal = @import("Terminal.zig");
 pub const Parser = @import("Parser.zig");
 pub const Stream = stream.Stream;
 pub const DeviceAttributeReq = ansi.DeviceAttributeReq;
+pub const DeviceStatusReq = ansi.DeviceStatusReq;
 pub const Mode = ansi.Mode;
 pub const EraseDisplay = csi.EraseDisplay;
 pub const EraseLine = csi.EraseLine;

src/terminal/stream.zig

@@ -295,12 +295,22 @@ pub fn Stream(comptime Handler: type) type {
                     while (p.next()) |attr| try self.handler.setAttribute(attr);
                 } else log.warn("unimplemented CSI callback: {}", .{action}),
 
+                // CPR - Request Cursor Postion Report
+                // TODO: test
+                'n' => if (@hasDecl(T, "deviceStatusReport")) try self.handler.deviceStatusReport(
+                    switch (action.params.len) {
+                        1 => @intToEnum(ansi.DeviceStatusReq, action.params[0]),
+                        else => {
+                            log.warn("invalid erase characters command: {}", .{action});
+                            return;
+                        },
+                    },
+                ) else log.warn("unimplemented CSI callback: {}", .{action}),
+
                 // DECSTBM - Set Top and Bottom Margins
                 // TODO: test
                 'r' => if (@hasDecl(T, "setTopAndBottomMargin")) switch (action.params.len) {
-                    0 => try self.handler.setTopAndBottomMargin(1, 0),
                     1 => try self.handler.setTopAndBottomMargin(action.params[0], 0),
-                    2 => try self.handler.setTopAndBottomMargin(action.params[0], action.params[1]),
                     else => log.warn("invalid DECSTBM command: {}", .{action}),
                 } else log.warn("unimplemented CSI callback: {}", .{action}),