More work on the diff kitten

kittens/diff/main.py

@@ -66,6 +66,14 @@ class DiffHandler(Handler):
             self.write(_('Calculating diff, please wait...'))
             return
         self.write(clear_screen())
+        for i in range(self.screen_size.rows - 1):
+            lpos = self.scroll_pos + i
+            if lpos >= len(self.diff_lines):
+                text = ''
+            else:
+                text = self.diff_lines[lpos].text
+            self.write(text)
+            self.write('\n\r')
 
     def on_key(self, key_event):
         if self.state is INITIALIZING:

kittens/diff/render.py

@@ -11,7 +11,27 @@ from kitty.fast_data_types import wcswidth
 from .collect import data_for_path, path_name_map
 from .config import formats
 
-sanitize_pat = re.compile('[\x00-\x1f\x7f\x80-\x9f]')
+
+class Reference:
+
+    __slots__ = ('path',)
+
+    def __init__(self, path):
+        self.path = path
+
+
+class Line:
+
+    __slots__ = ('text', 'ref')
+
+    def __init__(self, text, ref):
+        self.text = text
+        self.ref = ref
+
+
+def yield_lines_from(iterator, reference):
+    for text in iterator:
+        yield Line(text, reference)
 
 
 def human_readable(size, sep=' '):
@@ -29,6 +49,9 @@ def human_readable(size, sep=' '):
     return size + sep + suffix
 
 
+sanitize_pat = re.compile('[\x00-\x1f\x7f\x80-\x9f]')
+
+
 def sanitize_sub(m):
     return '<{:x}>'.format(ord(m.group()[0]))
 
@@ -94,10 +117,11 @@ def render_diff(collection, diff_map, args, columns):
     margin_size = max(3, len(str(largest_line_number)) + 1)
 
     for path, item_type, other_path in collection:
+        item_ref = Reference(path)
         if item_type == 'diff':
-            yield from title_lines(path, other_path, args, columns, margin_size)
+            yield from yield_lines_from(title_lines(path, other_path, args, columns, margin_size), item_ref)
             is_binary = isinstance(data_for_path(path), bytes)
             if is_binary:
-                yield from binary_lines(path, other_path, columns, margin_size)
+                yield from yield_lines_from(binary_lines(path, other_path, columns, margin_size), item_ref)
             else:
                 yield from lines_for_diff(path, other_path, diff_map[path], args, columns, margin_size)