Supporrt mixed case subsection names in Git config files

In the case of:

  [url "Foo"]
    insteadOf = Bar

We should return "Bar" for the key "url.Foo.insteadof", but not
for the key "url.foo.insteadof".  This requires splitting the
key into its components and only lower casing the section and
value name, leaving the subsection portion alone.

Signed-off-by: Shawn O. Pearce <sop@google.com>

git_config.py

@@ -29,6 +29,13 @@ REVIEW_CACHE = dict()
 def IsId(rev):
   return ID_RE.match(rev)
 
+def _key(name):
+  parts = name.split('.')
+  if len(parts) < 2:
+    return name.lower()
+  parts[ 0] = parts[ 0].lower()
+  parts[-1] = parts[-1].lower()
+  return '.'.join(parts)
 
 class GitConfig(object):
   _ForUser = None
@@ -54,8 +61,7 @@ class GitConfig(object):
   def Has(self, name, include_defaults = True):
     """Return true if this configuration file has the key.
     """
-    name = name.lower()
-    if name in self._cache:
+    if _key(name) in self._cache:
       return True
     if include_defaults and self.defaults:
       return self.defaults.Has(name, include_defaults = True)
@@ -83,10 +89,8 @@ class GitConfig(object):
        This configuration file is used first, if the key is not
        defined or all = True then the defaults are also searched.
     """
-    name = name.lower()
-
     try:
-      v = self._cache[name]
+      v = self._cache[_key(name)]
     except KeyError:
       if self.defaults:
         return self.defaults.GetString(name, all = all)
@@ -110,16 +114,16 @@ class GitConfig(object):
        The supplied value should be either a string,
        or a list of strings (to store multiple values).
     """
-    name = name.lower()
+    key = _key(name)
 
     try:
-      old = self._cache[name]
+      old = self._cache[key]
     except KeyError:
       old = []
 
     if value is None:
       if old:
-        del self._cache[name]
+        del self._cache[key]
         self._do('--unset-all', name)
 
     elif isinstance(value, list):
@@ -130,13 +134,13 @@ class GitConfig(object):
         self.SetString(name, value[0])
 
       elif old != value:
-        self._cache[name] = list(value)
+        self._cache[key] = list(value)
         self._do('--replace-all', name, value[0])
         for i in xrange(1, len(value)):
           self._do('--add', name, value[i])
 
     elif len(old) != 1 or old[0] != value:
-      self._cache[name] = [value]
+      self._cache[key] = [value]
       self._do('--replace-all', name, value)
 
   def GetRemote(self, name):
@@ -172,7 +176,7 @@ class GitConfig(object):
       lf = d.index('\n')
       nul = d.index('\0', lf + 1)
 
-      key = d[0:lf]
+      key = _key(d[0:lf])
       val = d[lf + 1:nul]
 
       if key in c: