[NaCl SDK] easy_template: fix bug when using % in an expression template.

BUG=none
R=bradnelson@google.com, bradnelson@chromium.org

Review URL: https://codereview.chromium.org/250773010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266627 0039d316-1c4b-4281-b951-d872f2087c98

native_client_sdk/src/build_tools/easy_template.py

@@ -32,9 +32,18 @@ def TemplateToPython(template, statement_re, expr_re):
         line_ending = line[-1] + line_ending
         line = line[:-1]
 
-      m = expr_re.search(line)
-      if m:
-        line = line.replace('%', '%%')
+      ms = list(expr_re.finditer(line))
+      if ms:
+        # Only replace % with %% outside of the expr matches.
+        new_line = ''
+        start = 0
+        for m in ms:
+          new_line += line[start:m.start()].replace('%', '%%')
+          new_line += line[m.start():m.end()]
+          start = m.end()
+        new_line += line[start:].replace('%', '%%')
+        line = new_line
+
         subst_line = r'r"""%s""" %% (%s,)' % (
             re.sub(expr_re, '%s', line),
             ', '.join(re.findall(expr_re, line)))

native_client_sdk/src/build_tools/tests/easy_template_test.py

@@ -109,6 +109,13 @@ struct Foo {
         {'name': 'name', 'type': 'std::string'},
         {'name': 'problems', 'type': 'array', 'basetype': 'int', 'size': 99}]})
 
+  def testModulo(self):
+    self._RunTest('No expression %', 'No expression %', {})
+    self._RunTest('% before {{3 + 4}}', '% before 7', {})
+    self._RunTest('{{2**8}} % after', '256 % after', {})
+    self._RunTest('inside {{8 % 3}}', 'inside 2', {})
+    self._RunTest('Everywhere % {{8 % 3}} %', 'Everywhere % 2 %', {})
+
 
 if __name__ == '__main__':
   unittest.main()