diff --git a/patch.py b/patch.py
index 4a67cadfc..8fe8b5c20 100644
--- a/patch.py
+++ b/patch.py
@@ -1,5 +1,5 @@
 # coding=utf8
-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Utility functions to handle patches."""
@@ -86,7 +86,10 @@ class FilePatchBase(object):
       out += 'R'
     else:
       out += ' '
-    return out + '  %s->%s' % (self.source_filename, self.filename)
+    out += '  '
+    if self.source_filename:
+      out += '%s->' % self.source_filename
+    return out + str(self.filename)
 
 
 class FilePatchDelete(FilePatchBase):
@@ -112,6 +115,18 @@ class FilePatchBinary(FilePatchBase):
     return self.data
 
 
+class Hunk(object):
+  """Parsed hunk data container."""
+
+  def __init__(self, start_src, lines_src, start_dst, lines_dst):
+    self.start_src = start_src
+    self.lines_src = lines_src
+    self.start_dst = start_dst
+    self.lines_dst = lines_dst
+    self.variation = self.lines_dst - self.lines_src
+    self.text = []
+
+
 class FilePatchDiff(FilePatchBase):
   """Patch for a single file."""
 
@@ -127,6 +142,7 @@ class FilePatchDiff(FilePatchBase):
       self._verify_git_header()
     else:
       self._verify_svn_header()
+    self.hunks = self._split_hunks()
     if self.source_filename and not self.is_new:
       self._fail('If source_filename is set, is_new must be also be set')
 
@@ -198,6 +214,65 @@ class FilePatchDiff(FilePatchBase):
     # http://codereview.chromium.org/download/issue6287022_3001_4010.diff
     return any(l.startswith('diff --git') for l in diff_header.splitlines())
 
+  def _split_hunks(self):
+    """Splits the hunks and does verification."""
+    hunks = []
+    for line in self.diff_hunks.splitlines(True):
+      if line.startswith('@@'):
+        match = re.match(r'^@@ -(\d+),(\d+) \+([\d,]+) @@.*$', line)
+        # File add will result in "-0,0 +1" but file deletion will result in
+        # "-1,N +0,0" where N is the number of lines deleted. That's from diff
+        # and svn diff. git diff doesn't exhibit this behavior.
+        if not match:
+          self._fail('Hunk header is unparsable')
+        if ',' in match.group(3):
+          start_dst, lines_dst = map(int, match.group(3).split(',', 1))
+        else:
+          start_dst = int(match.group(3))
+          lines_dst = 0
+        new_hunk = Hunk(int(match.group(1)), int(match.group(2)),
+                        start_dst, lines_dst)
+        if hunks:
+          if new_hunk.start_src <= hunks[-1].start_src:
+            self._fail('Hunks source lines are not ordered')
+          if new_hunk.start_dst <= hunks[-1].start_dst:
+            self._fail('Hunks destination lines are not ordered')
+        hunks.append(new_hunk)
+        continue
+      hunks[-1].text.append(line)
+
+    if len(hunks) == 1:
+      if hunks[0].start_src == 0 and hunks[0].lines_src == 0:
+        self.is_new = True
+      if hunks[0].start_dst == 0 and hunks[0].lines_dst == 0:
+        self.is_delete = True
+
+    if self.is_new and self.is_delete:
+      self._fail('Hunk header is all 0')
+
+    if not self.is_new and not self.is_delete:
+      for hunk in hunks:
+        variation = (
+            len([1 for i in hunk.text if i.startswith('+')]) -
+            len([1 for i in hunk.text if i.startswith('-')]))
+        if variation != hunk.variation:
+          self._fail(
+              'Hunk header is incorrect: %d vs %d' % (
+                variation, hunk.variation))
+        if not hunk.start_src:
+          self._fail(
+              'Hunk header start line is incorrect: %d' % hunk.start_src)
+        if not hunk.start_dst:
+          self._fail(
+              'Hunk header start line is incorrect: %d' % hunk.start_dst)
+        hunk.start_src -= 1
+        hunk.start_dst -= 1
+    if self.is_new and hunks:
+      hunks[0].start_dst -= 1
+    if self.is_delete and hunks:
+      hunks[0].start_src -= 1
+    return hunks
+
   def mangle(self, string):
     """Mangle a file path."""
     return '/'.join(string.replace('\\', '/').split('/')[self.patchlevel:])
diff --git a/testing_support/patches_data.py b/testing_support/patches_data.py
index b70f55ba3..80d36d24e 100644
--- a/testing_support/patches_data.py
+++ b/testing_support/patches_data.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -54,12 +54,63 @@ class RAW(object):
       '--- chrome/file.cc\tbar\n'
       '+++ /dev/null\tfoo\n')
 
+  DELETE2 = (
+      'Index: browser/extensions/extension_sidebar_api.cc\n'
+      '===================================================================\n'
+      '--- browser/extensions/extension_sidebar_api.cc\t(revision 116830)\n'
+      '+++ browser/extensions/extension_sidebar_api.cc\t(working copy)\n'
+      '@@ -1,19 +0,0 @@\n'
+      '-// Copyright (c) 2011 The Chromium Authors. All rights reserved.\n'
+      '-// Use of this source code is governed by a BSD-style license that\n'
+      '-// found in the LICENSE file.\n'
+      '-\n'
+      '-#include "base/command_line.h"\n'
+      '-#include "chrome/browser/extensions/extension_apitest.h"\n'
+      '-#include "chrome/common/chrome_switches.h"\n'
+      '-\n'
+      '-class SidebarApiTest : public ExtensionApiTest {\n'
+      '- public:\n'
+      '-  void SetUpCommandLine(CommandLine* command_line) {\n'
+      '-    ExtensionApiTest::SetUpCommandLine(command_line);\n'
+      '-    command_line->AppendSwitch(switches::Bleh);\n'
+      '-  }\n'
+      '-};\n'
+      '-\n'
+      '-IN_PROC_BROWSER_TEST_F(SidebarApiTest, Sidebar) {\n'
+      '-  ASSERT_TRUE(RunExtensionTest("sidebar")) << message_;\n'
+      '-}\n')
+
   # http://codereview.chromium.org/api/7530007/5001
   # http://codereview.chromium.org/download/issue7530007_5001_4011.diff
   CRAP_ONLY = (
       'Index: scripts/master/factory/skia/__init__.py\n'
       '===================================================================\n')
 
+  TWO_HUNKS = (
+      'Index: chrome/app/generated_resources.grd\n'
+      '===================================================================\n'
+      '--- chrome/app/generated_resources.grd\t(revision 116830)\n'
+      '+++ chrome/app/generated_resources.grd\t(working copy)\n'
+      '@@ -4169,9 +4169,6 @@\n'
+      '       <message name="IDS_EXTENSION_LOAD_OPTIONS_PAGE_FAILED" desc="">\n'
+      '   Could not load options page \'<ph name="OPTIONS_PAGE">$1<ex....\n'
+      ' </message>\n'
+      '-      <message name="IDS_EXTENSION_LOAD_SIDEBAR_PAGE_FAILED" desc="">\n'
+      '-        Could not load sidebar page \'<ph name="SIDEBAR_PAGE">$1<e...\n'
+      '-      </message>\n'
+      '       <if expr="is_win">\n'
+      '         <message name="IDS_EXTENSION_UNPACK_FAILED" desc="On wind...\n'
+      '           Can not unpack extension.  To safely unpack an extensio...\n'
+      '@@ -5593,9 +5590,6 @@\n'
+      '       <message name="IDS_ACCNAME_WEB_CONTENTS" desc="The acces...\n'
+      '         Web Contents\n'
+      '       </message>\n'
+      '-      <message name="IDS_ACCNAME_SIDE_BAR" desc="The acces...\n'
+      '-        Sidebar\n'
+      '-      </message>\n'
+      ' \n'
+      '       <!-- Browser Hung Plugin Detector -->\n'
+      '       <message name="IDS_UNKNOWN_PLUGIN_NAME" ...\n')
 
 class GIT(object):
   """Sample patches generated by git diff."""
@@ -206,3 +257,51 @@ class GIT(object):
       'diff --git a/git_cl/git-cl b/git_cl/git-cl\n'
       'old mode 100644\n'
       'new mode 100755\n')
+
+  FOUR_HUNKS = (
+      'Index: presubmit_support.py\n'
+      'diff --git a/presubmit_support.py b/presubmit_support.py\n'
+      'index 52416d3f..d56512f2 100755\n'
+      '--- a/presubmit_support.py\n'
+      '+++ b/presubmit_support.py\n'
+      '@@ -558,6 +558,7 @@ class SvnAffectedFile(AffectedFile):\n'
+      '     AffectedFile.__init__(self, *args, **kwargs)\n'
+      '     self._server_path = None\n'
+      '     self._is_text_file = None\n'
+      '+    self._diff = None\n'
+      ' \n'
+      '   def ServerPath(self):\n'
+      '     if self._server_path is None:\n'
+      '@@ -598,8 +599,10 @@ class SvnAffectedFile(AffectedFile):\n'
+      '     return self._is_text_file\n'
+      ' \n'
+      '   def GenerateScmDiff(self):\n'
+      '-    return scm.SVN.GenerateDiff(\n'
+      '-        [self.LocalPath()], self._local_root, False, None)\n'
+      '+    if self._diff is None:\n'
+      '+      self._diff = scm.SVN.GenerateDiff(\n'
+      '+          [self.LocalPath()], self._local_root, False, None)\n'
+      '+    return self._diff\n'
+      ' \n'
+      ' \n'
+      ' class GitAffectedFile(AffectedFile):\n'
+      '@@ -611,6 +614,7 @@ class GitAffectedFile(AffectedFile):\n'
+      '     AffectedFile.__init__(self, *args, **kwargs)\n'
+      '     self._server_path = None\n'
+      '     self._is_text_file = None\n'
+      '+    self._diff = None\n'
+      ' \n'
+      '   def ServerPath(self):\n'
+      '     if self._server_path is None:\n'
+      '@@ -645,7 +649,10 @@ class GitAffectedFile(AffectedFile):\n'
+      '     return self._is_text_file\n'
+      ' \n'
+      '   def GenerateScmDiff(self):\n'
+      '-    return scm.GIT.GenerateDiff(self._local_root, files=[self.Lo...\n'
+      '+    if self._diff is None:\n'
+      '+      self._diff = scm.GIT.GenerateDiff(\n'
+      '+          self._local_root, files=[self.LocalPath(),])\n'
+      '+    return self._diff\n'
+      ' \n'
+      ' \n'
+      ' class Change(object):\n')
diff --git a/tests/patch_test.py b/tests/patch_test.py
index 6cc829235..b1b4809d3 100755
--- a/tests/patch_test.py
+++ b/tests/patch_test.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -29,7 +29,8 @@ class PatchTest(unittest.TestCase):
       is_git_diff=False,
       is_new=False,
       patchlevel=0,
-      svn_properties=None):
+      svn_properties=None,
+      nb_hunks=None):
     svn_properties = svn_properties or []
     self.assertEquals(p.filename, filename)
     self.assertEquals(p.source_filename, source_filename)
@@ -45,8 +46,10 @@ class PatchTest(unittest.TestCase):
         self.assertEquals(p.get(), diff)
       else:
         self.assertEquals(p.get(True), diff)
-    if hasattr(p, 'svn_properties'):
-      self.assertEquals(p.svn_properties, svn_properties)
+    if hasattr(p, 'hunks'):
+      self.assertEquals(len(p.hunks), nb_hunks)
+    else:
+      self.assertEquals(None, nb_hunks)
 
   def testFilePatchDelete(self):
     p = patch.FilePatchDelete('foo', False)
@@ -66,32 +69,33 @@ class PatchTest(unittest.TestCase):
 
   def testFilePatchDiff(self):
     p = patch.FilePatchDiff('chrome/file.cc', RAW.PATCH, [])
-    self._check_patch(p, 'chrome/file.cc', RAW.PATCH)
+    self._check_patch(p, 'chrome/file.cc', RAW.PATCH, nb_hunks=1)
 
   def testFilePatchDiffHeaderMode(self):
     p = patch.FilePatchDiff('git_cl/git-cl', GIT.MODE_EXE, [])
     self._check_patch(
         p, 'git_cl/git-cl', GIT.MODE_EXE, is_git_diff=True, patchlevel=1,
-        svn_properties=[('svn:executable', '*')])
+        svn_properties=[('svn:executable', '*')], nb_hunks=0)
 
   def testFilePatchDiffHeaderModeIndex(self):
     p = patch.FilePatchDiff('git_cl/git-cl', GIT.MODE_EXE_JUNK, [])
     self._check_patch(
         p, 'git_cl/git-cl', GIT.MODE_EXE_JUNK, is_git_diff=True, patchlevel=1,
-        svn_properties=[('svn:executable', '*')])
+        svn_properties=[('svn:executable', '*')], nb_hunks=0)
 
   def testFilePatchDiffSvnNew(self):
     # The code path is different for git and svn.
     p = patch.FilePatchDiff('foo', RAW.NEW, [])
-    self._check_patch(p, 'foo', RAW.NEW, is_new=True)
+    self._check_patch(p, 'foo', RAW.NEW, is_new=True, nb_hunks=1)
 
   def testFilePatchDiffGitNew(self):
     # The code path is different for git and svn.
     p = patch.FilePatchDiff('foo', GIT.NEW, [])
     self._check_patch(
-        p, 'foo', GIT.NEW, is_new=True, is_git_diff=True, patchlevel=1)
+        p, 'foo', GIT.NEW, is_new=True, is_git_diff=True, patchlevel=1,
+        nb_hunks=1)
 
-  def testValidSvn(self):
+  def testSvn(self):
     # Should not throw.
     p = patch.FilePatchDiff('chrome/file.cc', RAW.PATCH, [])
     lines = RAW.PATCH.splitlines(True)
@@ -102,21 +106,21 @@ class PatchTest(unittest.TestCase):
     self.assertEquals(RAW.PATCH, p.get(True))
     self.assertEquals(RAW.PATCH, p.get(False))
 
-  def testValidSvnNew(self):
+  def testSvnNew(self):
     p = patch.FilePatchDiff('chrome/file.cc', RAW.MINIMAL_NEW, [])
     self.assertEquals(RAW.MINIMAL_NEW, p.diff_header)
     self.assertEquals('', p.diff_hunks)
     self.assertEquals(RAW.MINIMAL_NEW, p.get(True))
     self.assertEquals(RAW.MINIMAL_NEW, p.get(False))
 
-  def testValidSvnDelete(self):
+  def testSvnDelete(self):
     p = patch.FilePatchDiff('chrome/file.cc', RAW.MINIMAL_DELETE, [])
     self.assertEquals(RAW.MINIMAL_DELETE, p.diff_header)
     self.assertEquals('', p.diff_hunks)
     self.assertEquals(RAW.MINIMAL_DELETE, p.get(True))
     self.assertEquals(RAW.MINIMAL_DELETE, p.get(False))
 
-  def testValidSvnRename(self):
+  def testSvnRename(self):
     p = patch.FilePatchDiff('file_b', RAW.MINIMAL_RENAME, [])
     self.assertEquals(RAW.MINIMAL_RENAME, p.diff_header)
     self.assertEquals('', p.diff_hunks)
@@ -192,54 +196,85 @@ class PatchTest(unittest.TestCase):
     self.assertEquals(RAW.PATCH, patches.patches[0].get(True))
     self.assertEquals(RAW.PATCH, patches.patches[0].get(False))
 
+  def testTwoHunks(self):
+    name = 'chrome/app/generated_resources.grd'
+    p = patch.FilePatchDiff(name, RAW.TWO_HUNKS, [])
+    self._check_patch(p, name, RAW.TWO_HUNKS, nb_hunks=2)
+
+  def testGitThreeHunks(self):
+    p = patch.FilePatchDiff('presubmit_support.py', GIT.FOUR_HUNKS, [])
+    self._check_patch(
+        p, 'presubmit_support.py', GIT.FOUR_HUNKS, is_git_diff=True,
+        patchlevel=1,
+        nb_hunks=4)
+
   def testDelete(self):
     p = patch.FilePatchDiff('tools/clang_check/README.chromium', RAW.DELETE, [])
     self._check_patch(
-        p, 'tools/clang_check/README.chromium', RAW.DELETE, is_delete=True)
+        p, 'tools/clang_check/README.chromium', RAW.DELETE, is_delete=True,
+        nb_hunks=1)
+
+  def testDelete2(self):
+    name = 'browser/extensions/extension_sidebar_api.cc'
+    p = patch.FilePatchDiff(name, RAW.DELETE2, [])
+    self._check_patch(p, name, RAW.DELETE2, is_delete=True, nb_hunks=1)
 
   def testGitDelete(self):
     p = patch.FilePatchDiff('tools/clang_check/README.chromium', GIT.DELETE, [])
     self._check_patch(
         p, 'tools/clang_check/README.chromium', GIT.DELETE, is_delete=True,
-        is_git_diff=True, patchlevel=1)
+        is_git_diff=True, patchlevel=1, nb_hunks=1)
 
   def testGitRename(self):
     p = patch.FilePatchDiff('tools/run_local_server.sh', GIT.RENAME, [])
-    self._check_patch(p, 'tools/run_local_server.sh', GIT.RENAME,
-        is_git_diff=True, patchlevel=1,
-        source_filename='tools/run_local_server.PY', is_new=True)
+    self._check_patch(
+        p,
+        'tools/run_local_server.sh',
+        GIT.RENAME,
+        is_git_diff=True,
+        patchlevel=1,
+        source_filename='tools/run_local_server.PY',
+        is_new=True,
+        nb_hunks=0)
 
   def testGitRenamePartial(self):
     p = patch.FilePatchDiff(
         'chromeos/views/webui_menu_widget.h', GIT.RENAME_PARTIAL, [])
     self._check_patch(
-        p, 'chromeos/views/webui_menu_widget.h', GIT.RENAME_PARTIAL,
-        source_filename='chromeos/views/DOMui_menu_widget.h', is_git_diff=True,
-        patchlevel=1, is_new=True)
+        p,
+        'chromeos/views/webui_menu_widget.h',
+        GIT.RENAME_PARTIAL,
+        source_filename='chromeos/views/DOMui_menu_widget.h',
+        is_git_diff=True,
+        patchlevel=1,
+        is_new=True,
+        nb_hunks=1)
 
   def testGitCopy(self):
     p = patch.FilePatchDiff('pp', GIT.COPY, [])
-    self._check_patch(p, 'pp', GIT.COPY, is_git_diff=True, patchlevel=1,
-        source_filename='PRESUBMIT.py', is_new=True)
+    self._check_patch(
+        p, 'pp', GIT.COPY, is_git_diff=True, patchlevel=1,
+        source_filename='PRESUBMIT.py', is_new=True, nb_hunks=0)
 
   def testOnlyHeader(self):
     p = patch.FilePatchDiff('file_a', RAW.MINIMAL, [])
-    self._check_patch(p, 'file_a', RAW.MINIMAL)
+    self._check_patch(p, 'file_a', RAW.MINIMAL, nb_hunks=0)
 
   def testSmallest(self):
     p = patch.FilePatchDiff('file_a', RAW.NEW_NOT_NULL, [])
-    self._check_patch(p, 'file_a', RAW.NEW_NOT_NULL)
+    self._check_patch(p, 'file_a', RAW.NEW_NOT_NULL, is_new=True, nb_hunks=1)
 
   def testRenameOnlyHeader(self):
     p = patch.FilePatchDiff('file_b', RAW.MINIMAL_RENAME, [])
     self._check_patch(
-        p, 'file_b', RAW.MINIMAL_RENAME, source_filename='file_a', is_new=True)
+        p, 'file_b', RAW.MINIMAL_RENAME, source_filename='file_a', is_new=True,
+        nb_hunks=0)
 
   def testGitCopyPartial(self):
     p = patch.FilePatchDiff('wtf2', GIT.COPY_PARTIAL, [])
     self._check_patch(
         p, 'wtf2', GIT.COPY_PARTIAL, source_filename='wtf', is_git_diff=True,
-        patchlevel=1, is_new=True)
+        patchlevel=1, is_new=True, nb_hunks=1)
 
   def testGitCopyPartialAsSvn(self):
     p = patch.FilePatchDiff('wtf2', GIT.COPY_PARTIAL, [])
@@ -263,14 +298,20 @@ class PatchTest(unittest.TestCase):
   def testGitNewExe(self):
     p = patch.FilePatchDiff('natsort_test.py', GIT.NEW_EXE, [])
     self._check_patch(
-        p, 'natsort_test.py', GIT.NEW_EXE, is_new=True, is_git_diff=True,
-        patchlevel=1, svn_properties=[('svn:executable', '*')])
+        p,
+        'natsort_test.py',
+        GIT.NEW_EXE,
+        is_new=True,
+        is_git_diff=True,
+        patchlevel=1,
+        svn_properties=[('svn:executable', '*')],
+        nb_hunks=1)
 
   def testGitNewMode(self):
     p = patch.FilePatchDiff('natsort_test.py', GIT.NEW_MODE, [])
     self._check_patch(
         p, 'natsort_test.py', GIT.NEW_MODE, is_new=True, is_git_diff=True,
-        patchlevel=1)
+        patchlevel=1, nb_hunks=1)
 
   def testPatchsetOrder(self):
     # Deletes must be last.
diff --git a/tests/rietveld_test.py b/tests/rietveld_test.py
index fa13945e9..bad929c38 100755
--- a/tests/rietveld_test.py
+++ b/tests/rietveld_test.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -104,8 +104,8 @@ class RietveldTest(unittest.TestCase):
     ]
     patches = self.rietveld.get_patch(123, 456)
     self.assertEquals(2, len(patches.patches))
-    # TODO(maruel): svn sucks.
-    self._check_patch(patches.patches[0], 'file_a', RAW.NEW_NOT_NULL)
+    self._check_patch(
+        patches.patches[0], 'file_a', RAW.NEW_NOT_NULL, is_new=True)
     self._check_patch(patches.patches[1], 'foo', RAW.NEW, is_new=True)
 
   def test_get_patch_add(self):