Implement DSR

kitty/data-types.h

@@ -332,6 +332,7 @@ void screen_delete_characters(Screen *self, unsigned int count);
 void screen_erase_characters(Screen *self, unsigned int count);
 void report_device_attributes(Screen *self, unsigned int UNUSED mode, bool UNUSED secondary);
 void select_graphic_rendition(Screen *self, unsigned int *params, unsigned int count);
+void report_device_status(Screen *self, unsigned int which, bool UNUSED);
 #define DECLARE_CH_SCREEN_HANDLER(name) void screen_##name(Screen *screen, uint8_t ch);
 DECLARE_CH_SCREEN_HANDLER(bell)
 DECLARE_CH_SCREEN_HANDLER(backspace)

kitty/parser.c

@@ -342,6 +342,8 @@ HANDLER(csi) {
         SET_MODE(screen_reset_mode); \
     case SGR: \
         CSI_HANDLER_MULTIPLE(select_graphic_rendition); \
+    case DSR: \
+        CALL_CSI_HANDLER1P(report_device_status, 0, '?'); \
 
     uint8_t ch = buf[(*pos)++];
     unsigned int params[MAX_PARAMS], p1, p2, count, i;

kitty/screen.c

@@ -753,6 +753,28 @@ void report_device_attributes(Screen *self, unsigned int UNUSED mode, bool UNUSE
     write_to_child(self, "\x1b[?62c", 0);  // Corresponds to VT-220
 }
 
+void report_device_status(Screen *self, unsigned int which, bool UNUSED private) {
+    // We dont implement the private device status codes, since I haven;t come
+    // across any programs that use them
+    unsigned int x, y;
+    char buf[50] = {0};
+    switch(which) {
+        case 5:  // device status
+            write_to_child(self, "\x1b[0n", 0); 
+            break;
+        case 6:  // cursor position
+            x = self->cursor->x; y = self->cursor->y;
+            if (x >= self->columns) {
+                if (y < self->lines - 1) { x = 0; y++; }
+                else x--;
+            }
+            if (self->modes.mDECOM) y -= MAX(y, self->margin_top);
+            x++; y++;  // 1-based indexing
+            if (snprintf(buf, sizeof(buf) - 1, "\x1b[%u;%uR", y, x) > 0) write_to_child(self, buf, 0);
+            break;
+    }
+}
+
 // }}}
 
 // Python interface {{{
@@ -915,6 +937,7 @@ static PyMethodDef methods[] = {
 };
 
 static PyMemberDef members[] = {
+    {"callbacks", T_OBJECT_EX, offsetof(Screen, callbacks), 0, "callbacks"},
     {"cursor", T_OBJECT_EX, offsetof(Screen, cursor), 0, "cursor"},
     {"linebuf", T_OBJECT_EX, offsetof(Screen, linebuf), 0, "linebuf"},
     {"lines", T_UINT, offsetof(Screen, lines), 0, "lines"},

kitty_tests/parser.py

@@ -17,6 +17,18 @@ class CmdDump(list):
         self.append(a)
 
 
+class Callbacks:
+
+    def __init__(self):
+        self.clear()
+
+    def write_to_child(self, data):
+        self.wtcbuf += data
+
+    def clear(self):
+        self.wtcbuf = b''
+
+
 class TestScreen(BaseTest):
 
     def parse_buytes_dump(self, s, x, *cmds):
@@ -93,3 +105,14 @@ class TestScreen(BaseTest):
         pb('\033[38;2;1;2;3;48;2;7;8;9m', ('select_graphic_rendition', 10))
         self.ae(s.cursor.fg, 1 << 24 | 2 << 16 | 3 << 8 | 3)
         self.ae(s.cursor.bg, 7 << 24 | 8 << 16 | 9 << 8 | 3)
+        c = Callbacks()
+        s.callbacks = c
+        pb('\033[5n', ('report_device_status', 5, 0))
+        self.ae(c.wtcbuf, b'\033[0n')
+        c.clear()
+        pb('\033[6n', ('report_device_status', 6, 0))
+        self.ae(c.wtcbuf, b'\033[1;1R')
+        pb('12345')
+        c.clear()
+        pb('\033[6n', ('report_device_status', 6, 0))
+        self.ae(c.wtcbuf, b'\033[2;1R')