Implement the fast draw path for single width characters

kitty_tests/__init__.py

@@ -2,9 +2,32 @@
 # vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
 
+from collections import defaultdict
 from unittest import TestCase
 
+from kitty.screen import Screen
+from kitty.tracker import ChangeTracker
+from kitty.config import defaults
+
 
 class BaseTest(TestCase):
 
     ae = TestCase.assertEqual
+
+    def create_screen(self, cols=5, lines=5, history_size=5):
+        t = ChangeTracker()
+        opts = defaults._replace(scrollback_lines=history_size)
+        s = Screen(opts, t, columns=cols, lines=lines)
+        return s, t
+
+    def assertChanges(self, t, ignore='', **expected_changes):
+        actual_changes = t.consolidate_changes()
+        ignore = frozenset(ignore.split())
+        for k, v in actual_changes.items():
+            if isinstance(v, defaultdict):
+                v = dict(v)
+            if k not in ignore:
+                if k in expected_changes:
+                    self.ae(expected_changes[k], v)
+                else:
+                    self.assertFalse(v)

kitty_tests/screen.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2016, Kovid Goyal <kovid at kovidgoyal.net>
+
+from . import BaseTest
+
+from kitty.screen import mo
+
+
+class TestScreen(BaseTest):
+
+    def test_draw_fast(self):
+        # Test in line-wrap, non-insert mode
+        s, t = self.create_screen()
+        s.draw(b'a' * 5)
+        self.ae(str(s.linebuf[0]), 'a' * 5)
+        self.ae(s.cursor.x, 5), self.ae(s.cursor.y, 0)
+        self.assertChanges(t, ignore='cursor', cells={0: ((0, 4),)})
+        s.draw(b'b' * 7)
+        self.assertTrue(s.linebuf[1].continued)
+        self.assertTrue(s.linebuf[2].continued)
+        self.ae(str(s.linebuf[0]), 'a' * 5)
+        self.ae(str(s.linebuf[1]), 'b' * 5)
+        self.ae(str(s.linebuf[2]), 'b' * 2 + ' ' * 3)
+        self.ae(s.cursor.x, 2), self.ae(s.cursor.y, 2)
+        self.assertChanges(t, ignore='cursor', cells={1: ((0, 4),), 2: ((0, 1),)})
+        s.draw(b'c' * 15)
+        self.ae(str(s.linebuf[0]), 'b' * 5)
+        self.ae(str(s.linebuf[1]), 'bbccc')
+
+        # Now test without line-wrap
+        s.reset(), t.reset()
+        s.reset_mode(mo.DECAWM)
+        s.draw(b'0123456789')
+        self.ae(str(s.linebuf[0]), '56789')
+        self.ae(s.cursor.x, 5), self.ae(s.cursor.y, 0)
+        self.assertChanges(t, ignore='cursor', cells={0: ((0, 4),)})
+        s.draw(b'ab')
+        self.ae(str(s.linebuf[0]), '567ab')
+        self.ae(s.cursor.x, 5), self.ae(s.cursor.y, 0)
+        self.assertChanges(t, ignore='cursor', cells={0: ((3, 4),)})
+
+        # Now test in insert mode
+        s.reset(), t.reset()
+        s.set_mode(mo.IRM)
+        s.draw(b'12345' * 5)
+        s.cursor_back(5)
+        self.ae(s.cursor.x, 0), self.ae(s.cursor.y, 4)
+        t.reset()
+        s.draw(b'ab')
+        self.ae(str(s.linebuf[4]), 'ab123')
+        self.ae((s.cursor.x, s.cursor.y), (2, 4))
+        self.assertChanges(t, ignore='cursor', cells={4: ((0, 4),)})