Modify presubmit checks to work on changed lines only.

presubmit_support.py

Index: presubmit_support.py
diff --git a/presubmit_support.py b/presubmit_support.py
index 79bc306bdcb306be12afca6929d25e0b548e4177..0f0cf8938791d4c9b207586c77738e9e940b6096 100755
--- a/presubmit_support.py
+++ b/presubmit_support.py
@@ -86,11 +86,9 @@ def PromptYesNo(input_stream, output_stream, prompt):
 def _RightHandSideLinesImpl(affected_files):
   """Implements RightHandSideLines for InputApi and GclChange."""
   for af in affected_files:
-    lines = af.NewContents()
-    line_number = 0
+    lines = af.ChangedContents()
     for line in lines:
-      line_number += 1
-      yield (af, line_number, line)
+      yield (af, line[0], line[1])
 
 
 class OutputApi(object):
@@ -481,6 +479,27 @@ class AffectedFile(object):
     """
     raise NotImplementedError()  # Implement if/when needed.
 
+  def ChangedContents(self):
+    # Return a list of tuples (line number, line text) of all new lines in the
+    # file. This relies on the git diff output describing each changed code

[M-A Ruel, 2011/02/09 14:16:10]

the scm diff output

[vb, 2011/02/09 18:24:41]

Done.

+    # section with a line of the form
+    #
+    # ^@@ <old line num>,<old size> <new line num>,<new size> @@$
+    #
+    new_lines = []
+    line_num = 0
+    diff_text = self.GenerateScmDiff()
+    for line in diff_text.split('\n'):

[M-A Ruel, 2011/02/09 14:16:10]

for line in self.GenerateScmDiff().splitlines():

and remove line 491.

[vb, 2011/02/09 18:24:41]

Done.

+      m = re.match('^@@ [0-9\,\+\-]+ \+([0-9]+)\,[0-9]+ @@', line)

[M-A Ruel, 2011/02/09 14:16:10]

m = re.match(r'^@@ [0-9\,\+\-]+ \+([0-9]+)\,[0-9]+ @@', line)

[vb, 2011/02/09 18:24:41]

Done.

+      if m:
+        line_num = int(m.groups(1)[0])
+        continue
+      if re.search('^\+[^\+]', line):

[M-A Ruel, 2011/02/09 14:16:10]

if re.search(r'^\+[^\+]', line):

[vb, 2011/02/09 18:24:41]

Done.

+        new_lines.append((line_num, line[1:]))
+      if not re.search('^\-[^\-]', line):

[M-A Ruel, 2011/02/09 14:16:10]

if not re.search(r'^\-[^\-]', line):

[vb, 2011/02/09 18:24:41]

Done.

+        line_num += 1
+    return new_lines
+
   def __str__(self):
     return self.LocalPath()
 
@@ -532,6 +551,8 @@ class SvnAffectedFile(AffectedFile):
         self._is_text_file = (not mime_type or mime_type.startswith('text/'))
     return self._is_text_file
 
+  def GenerateScmDiff(self):
+    return scm.SVN.GenerateDiff(self.AbsoluteLocalPath())
 
 class GitAffectedFile(AffectedFile):
   """Representation of a file in a change out of a git checkout."""
@@ -577,6 +598,10 @@ class GitAffectedFile(AffectedFile):
         self._is_text_file = os.path.isfile(self.AbsoluteLocalPath())
     return self._is_text_file
 
+  def GenerateScmDiff(self):
+    return scm.GIT.GenerateDiff(
+      os.path.dirname(self.AbsoluteLocalPath()),
+      files=[os.path.basename(self.AbsoluteLocalPath()),])
 
 class Change(object):
   """Describe a change.