commit 038b95dcaea8d5f92d552e1632723a7958b602af
Author: jomae <jun66j5@gmail.com>
Date:   Fri May 9 16:55:59 2014 +0900

    1.0.2dev: improved diff with "ignore whitespace changes"

diff --git a/trac/versioncontrol/diff.py b/trac/versioncontrol/diff.py
index 8475b05..b6637f3 100644
--- a/trac/versioncontrol/diff.py
+++ b/trac/versioncontrol/diff.py
@@ -94,50 +94,61 @@ def filter_ignorable_lines(hunks, fromlines, tolines, context,
 
     See `get_filtered_hunks` for the parameter descriptions.
     """
-    def is_ignorable(tag, fromlines, tolines):
-        if tag == 'delete' and ignore_blank_lines:
-            if ''.join(fromlines) == '':
-                return True
-        elif tag == 'insert' and ignore_blank_lines:
-            if ''.join(tolines) == '':
-                return True
-        elif tag == 'replace' and (ignore_case or ignore_space_changes):
-            if len(fromlines) != len(tolines):
-                return False
-            def f(str):
-                if ignore_case:
-                    str = str.lower()
-                if ignore_space_changes:
-                    str = ' '.join(str.split())
-                return str
-            for i in range(len(fromlines)):
-                if f(fromlines[i]) != f(tolines[i]):
-                    return False
-            return True
+
+    if ignore_case or ignore_space_changes:
+        def normalize(value):
+            if ignore_case:
+                value = value.lower()
+            if ignore_space_changes:
+                value = ' '.join(value.split())
+            return value
+    else:
+        normalize = None
+
+    def filter_ignores(opcodes):
+        ignored = False
+        filtered = []
+        for tag, i1, i2, j1, j2 in opcodes:
+            if normalize and tag == 'replace':
+                norm_fromlines = map(normalize, fromlines[i1:i2])
+                norm_tolines = map(normalize, tolines[j1:j2])
+                matcher = difflib.SequenceMatcher(None, norm_fromlines,
+                                                  norm_tolines)
+                for tag, norm_i1, norm_i2, norm_j1, norm_j2 in \
+                        matcher.get_opcodes():
+                    filtered.append((tag, i1 + norm_i1, i1 + norm_i2,
+                                          j1 + norm_j1, j1 + norm_j2))
+                    if tag != 'replace':
+                        ignored = True
+                continue
+            if ignore_blank_lines and tag == 'delete':
+                if all(fromlines[n] == '' for n in xrange(i1, i2)):
+                    ignored = True
+                    tag = 'equal'
+            if ignore_blank_lines and tag == 'insert':
+                if all(tolines[n] == '' for n in xrange(j1, j2)):
+                    ignored = True
+                    tag = 'equal'
+            filtered.append((tag, i1, i2, j1, j2))
+        return ignored, filtered
 
     hunks = list(hunks)
     opcodes = []
     ignored_lines = False
     prev = None
     for hunk in hunks:
-        for tag, i1, i2, j1, j2 in hunk:
-            if tag == 'equal':
-                if prev:
-                    prev = (tag, prev[1], i2, prev[3], j2)
-                else:
-                    prev = (tag, i1, i2, j1, j2)
+        if ignore_blank_lines or ignore_case or ignore_space_changes:
+            ignored, hunk = filter_ignores(hunk)
+            if ignored:
+                ignored_lines = True
+        for curr in hunk:
+            if prev is None:
+                prev = curr
+            elif prev[0] == curr[0]:
+                prev = (prev[0], prev[1], curr[2], prev[3], curr[4])
             else:
-                if is_ignorable(tag, fromlines[i1:i2], tolines[j1:j2]):
-                    ignored_lines = True
-                    if prev:
-                        prev = 'equal', prev[1], i2, prev[3], j2
-                    else:
-                        prev = 'equal', i1, i2, j1, j2
-                    continue
-                if prev:
-                    opcodes.append(prev)
-                opcodes.append((tag, i1, i2, j1, j2))
-                prev = None
+                opcodes.append(prev)
+                prev = curr
     if prev:
         opcodes.append(prev)
 
diff --git a/trac/versioncontrol/tests/diff.py b/trac/versioncontrol/tests/diff.py
index 68e6e47..b168f93 100644
--- a/trac/versioncontrol/tests/diff.py
+++ b/trac/versioncontrol/tests/diff.py
@@ -85,6 +85,40 @@ class DiffTestCase(unittest.TestCase):
         self.assertEqual(('equal', 0, 2, 0, 2), opcodes.next())
         self.assertRaises(StopIteration, opcodes.next)
 
+    def test_space_changes_2(self):
+        left = """\
+try:
+    try:
+        func()
+        commit()
+    except:
+        rollback()
+finally:
+    cleanup()
+"""
+        left = left.splitlines()
+        right = """\
+try:
+    func()
+    commit()
+except:
+    rollback()
+finally:
+    cleanup()
+"""
+        right = right.splitlines()
+        opcodes = get_opcodes(left, right, ignore_space_changes=0)
+        self.assertEqual(('equal', 0, 1, 0, 1), opcodes.next())
+        self.assertEqual(('replace', 1, 6, 1, 5), opcodes.next())
+        self.assertEqual(('equal', 6, 8, 5, 7), opcodes.next())
+        self.assertRaises(StopIteration, opcodes.next)
+
+        opcodes = get_opcodes(left, right, ignore_space_changes=1)
+        self.assertEqual(('equal', 0, 1, 0, 1), opcodes.next())
+        self.assertEqual(('delete', 1, 2, 1, 1), opcodes.next())
+        self.assertEqual(('equal', 2, 8, 1, 7), opcodes.next())
+        self.assertRaises(StopIteration, opcodes.next)
+
     def test_case_changes(self):
         opcodes = get_opcodes(['A', 'B b'], ['A', 'B B'], ignore_case=0)
         self.assertEqual(('equal', 0, 1, 0, 1), opcodes.next())