diff --git a/SUBMITTING_PATCHES b/SUBMITTING_PATCHES
index 50e2cf7..8656ee7 100644
--- a/SUBMITTING_PATCHES
+++ b/SUBMITTING_PATCHES
@@ -4,7 +4,9 @@
  - Provide a meaningful commit message.
  - Check for coding errors with pylint
  - Make sure all code is under the Apache License, 2.0.
- - Publish your changes for review:
+ - Publish your changes for review.
+ - Make corrections if requested.
+ - Verify your changes on gerrit so they can be submitted.
 
    git push https://gerrit-review.googlesource.com/git-repo HEAD:refs/for/master
 
@@ -75,6 +77,17 @@
 
   https://gerrit-review.googlesource.com/new-password
 
+Ensure that you have the local commit hook installed to automatically
+add a ChangeId to your commits:
+
+    curl -Lo `git rev-parse --git-dir`/hooks/commit-msg https://gerrit-review.googlesource.com/tools/hooks/commit-msg
+    chmod +x `git rev-parse --git-dir`/hooks/commit-msg
+
+If you have already committed your changes you will need to amend the commit
+to get the ChangeId added.
+
+    git commit --amend
+
 Push your patches over HTTPS to the review server, possibly through
 a remembered remote to make this easier in the future:
 
@@ -85,3 +98,18 @@
 
 You will be automatically emailed a copy of your commits, and any
 comments made by the project maintainers.
+
+
+(5) Make changes if requested
+
+The project maintainer who reviews your changes might request changes to your
+commit. If you make the requested changes you will need to amend your commit
+and push it to the review server again.
+
+
+(6) Verify your changes on gerrit
+
+After you receive a Code-Review+2 from the maintainer, select the Verified
+button on the gerrit page for the change. This verifies that you have tested
+your changes and notifies the maintainer that they are ready to be submitted.
+The maintainer will then submit your changes to the repository.
diff --git a/command.py b/command.py
index 38cacd3..bc2f950 100644
--- a/command.py
+++ b/command.py
@@ -31,7 +31,7 @@
   manifest = None
   _optparse = None
 
-  def WantPager(self, opt):
+  def WantPager(self, _opt):
     return False
 
   def ReadEnvironmentOptions(self, opts):
@@ -63,7 +63,7 @@
         usage = self.helpUsage.strip().replace('%prog', me)
       except AttributeError:
         usage = 'repo %s' % self.NAME
-      self._optparse = optparse.OptionParser(usage = usage)
+      self._optparse = optparse.OptionParser(usage=usage)
       self._Options(self._optparse)
     return self._optparse
 
@@ -106,13 +106,13 @@
   def _UpdatePathToProjectMap(self, project):
     self._by_path[project.worktree] = project
 
-  def _GetProjectByPath(self, path):
+  def _GetProjectByPath(self, manifest, path):
     project = None
     if os.path.exists(path):
       oldpath = None
-      while path \
-        and path != oldpath \
-        and path != self.manifest.topdir:
+      while path and \
+            path != oldpath and \
+            path != manifest.topdir:
         try:
           project = self._by_path[path]
           break
@@ -126,16 +126,19 @@
         pass
     return project
 
-  def GetProjects(self, args, groups='', missing_ok=False, submodules_ok=False):
+  def GetProjects(self, args, manifest=None, groups='', missing_ok=False,
+                  submodules_ok=False):
     """A list of projects that match the arguments.
     """
-    all_projects_list = self.manifest.projects
+    if not manifest:
+      manifest = self.manifest
+    all_projects_list = manifest.projects
     result = []
 
-    mp = self.manifest.manifestProject
+    mp = manifest.manifestProject
 
     if not groups:
-        groups = mp.config.GetString('manifest.groups')
+      groups = mp.config.GetString('manifest.groups')
     if not groups:
       groups = 'default,platform-' + platform.system().lower()
     groups = [x for x in re.split(r'[,\s]+', groups) if x]
@@ -148,29 +151,28 @@
                                   for p in project.GetDerivedSubprojects())
       all_projects_list.extend(derived_projects.values())
       for project in all_projects_list:
-        if ((missing_ok or project.Exists) and
-            project.MatchesGroups(groups)):
+        if (missing_ok or project.Exists) and project.MatchesGroups(groups):
           result.append(project)
     else:
       self._ResetPathToProjectMap(all_projects_list)
 
       for arg in args:
-        projects = self.manifest.GetProjectsWithName(arg)
+        projects = manifest.GetProjectsWithName(arg)
 
         if not projects:
           path = os.path.abspath(arg).replace('\\', '/')
-          project = self._GetProjectByPath(path)
+          project = self._GetProjectByPath(manifest, path)
 
           # If it's not a derived project, update path->project mapping and
           # search again, as arg might actually point to a derived subproject.
-          if (project and not project.Derived and
-              (submodules_ok or project.sync_s)):
+          if (project and not project.Derived and (submodules_ok or
+                                                   project.sync_s)):
             search_again = False
             for subproject in project.GetDerivedSubprojects():
               self._UpdatePathToProjectMap(subproject)
               search_again = True
             if search_again:
-              project = self._GetProjectByPath(path) or project
+              project = self._GetProjectByPath(manifest, path) or project
 
           if project:
             projects = [project]
@@ -191,17 +193,24 @@
     result.sort(key=_getpath)
     return result
 
-  def FindProjects(self, args):
+  def FindProjects(self, args, inverse=False):
     result = []
     patterns = [re.compile(r'%s' % a, re.IGNORECASE) for a in args]
     for project in self.GetProjects(''):
       for pattern in patterns:
-        if pattern.search(project.name) or pattern.search(project.relpath):
+        match = pattern.search(project.name) or pattern.search(project.relpath)
+        if not inverse and match:
           result.append(project)
           break
+        if inverse and match:
+          break
+      else:
+        if inverse:
+          result.append(project)
     result.sort(key=lambda project: project.relpath)
     return result
 
+
 # pylint: disable=W0223
 # Pylint warns that the `InteractiveCommand` and `PagedCommand` classes do not
 # override method `Execute` which is abstract in `Command`.  Since that method
@@ -211,19 +220,33 @@
   """Command which requires user interaction on the tty and
      must not run within a pager, even if the user asks to.
   """
-  def WantPager(self, opt):
+  def WantPager(self, _opt):
     return False
 
+
 class PagedCommand(Command):
   """Command which defaults to output in a pager, as its
      display tends to be larger than one screen full.
   """
-  def WantPager(self, opt):
+  def WantPager(self, _opt):
     return True
 
 # pylint: enable=W0223
 
+
 class MirrorSafeCommand(object):
   """Command permits itself to run within a mirror,
      and does not require a working directory.
   """
+
+
+class GitcAvailableCommand(object):
+  """Command that requires GITC to be available, but does
+     not require the local client to be a GITC client.
+  """
+
+
+class GitcClientCommand(object):
+  """Command that requires the local client to be a GITC
+     client.
+  """
diff --git a/docs/manifest-format.txt b/docs/manifest-format.txt
index 1aa9396..140a782 100644
--- a/docs/manifest-format.txt
+++ b/docs/manifest-format.txt
@@ -47,10 +47,12 @@
     <!ATTLIST default sync-s      CDATA #IMPLIED>
 
     <!ELEMENT manifest-server (EMPTY)>
-    <!ATTLIST url              CDATA #REQUIRED>
+    <!ATTLIST manifest-server url CDATA #REQUIRED>
 
     <!ELEMENT project (annotation*,
-                       project*)>
+                       project*,
+                       copyfile*,
+                       linkfile*)>
     <!ATTLIST project name        CDATA #REQUIRED>
     <!ATTLIST project path        CDATA #IMPLIED>
     <!ATTLIST project remote      IDREF #IMPLIED>
@@ -68,7 +70,15 @@
     <!ATTLIST annotation value CDATA #REQUIRED>
     <!ATTLIST annotation keep  CDATA "true">
 
-    <!ELEMENT extend-project>
+    <!ELEMENT copyfile (EMPTY)>
+    <!ATTLIST copyfile src  CDATA #REQUIRED>
+    <!ATTLIST copyfile dest CDATA #REQUIRED>
+
+    <!ELEMENT linkfile (EMPTY)>
+    <!ATTLIST linkfile src CDATA #REQUIRED>
+    <!ATTLIST linkfile dest CDATA #REQUIRED>
+
+    <!ELEMENT extend-project (EMPTY)>
     <!ATTLIST extend-project name CDATA #REQUIRED>
     <!ATTLIST extend-project path CDATA #IMPLIED>
     <!ATTLIST extend-project groups CDATA #IMPLIED>
@@ -285,6 +295,21 @@
 "false".  This attribute determines whether or not the annotation will
 be kept when exported with the manifest subcommand.
 
+Element copyfile
+----------------
+
+Zero or more copyfile elements may be specified as children of a
+project element. Each element describes a src-dest pair of files;
+the "src" file will be copied to the "dest" place during 'repo sync'
+command.
+"src" is project relative, "dest" is relative to the top of the tree.
+
+Element linkfile
+----------------
+
+It's just like copyfile and runs at the same time as copyfile but
+instead of copying it creates a symlink.
+
 Element remove-project
 ----------------------
 
diff --git a/git_command.py b/git_command.py
index 0893bff..9f7d293 100644
--- a/git_command.py
+++ b/git_command.py
@@ -168,6 +168,9 @@
       if p is not None:
         s = p + ' ' + s
       _setenv(env, 'GIT_CONFIG_PARAMETERS', s)
+    if 'GIT_ALLOW_PROTOCOL' not in env:
+      _setenv(env, 'GIT_ALLOW_PROTOCOL',
+              'file:git:http:https:ssh:persistent-http:persistent-https:sso:rpc')
 
     if project:
       if not cwd:
diff --git a/git_config.py b/git_config.py
index 8ded7c2..0379181 100644
--- a/git_config.py
+++ b/git_config.py
@@ -15,6 +15,8 @@
 
 from __future__ import print_function
 
+import contextlib
+import errno
 import json
 import os
 import re
@@ -502,6 +504,43 @@
     return m.group(1)
   return None
 
+@contextlib.contextmanager
+def GetUrlCookieFile(url, quiet):
+  if url.startswith('persistent-'):
+    try:
+      p = subprocess.Popen(
+          ['git-remote-persistent-https', '-print_config', url],
+          stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+          stderr=subprocess.PIPE)
+      try:
+        cookieprefix = 'http.cookiefile='
+        proxyprefix = 'http.proxy='
+        cookiefile = None
+        proxy = None
+        for line in p.stdout:
+          line = line.strip()
+          if line.startswith(cookieprefix):
+            cookiefile = line[len(cookieprefix):]
+          if line.startswith(proxyprefix):
+            proxy = line[len(proxyprefix):]
+        # Leave subprocess open, as cookie file may be transient.
+        if cookiefile or proxy:
+          yield cookiefile, proxy
+          return
+      finally:
+        p.stdin.close()
+        if p.wait():
+          err_msg = p.stderr.read()
+          if ' -print_config' in err_msg:
+            pass  # Persistent proxy doesn't support -print_config.
+          elif not quiet:
+            print(err_msg, file=sys.stderr)
+    except OSError as e:
+      if e.errno == errno.ENOENT:
+        pass  # No persistent proxy.
+      raise
+  yield GitConfig.ForUser().GetString('http.cookiefile'), None
+
 def _preconnect(url):
   m = URI_ALL.match(url)
   if m:
diff --git a/gitc_utils.py b/gitc_utils.py
new file mode 100644
index 0000000..0f3e181
--- /dev/null
+++ b/gitc_utils.py
@@ -0,0 +1,148 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+import os
+import platform
+import re
+import sys
+import time
+
+import git_command
+import git_config
+import wrapper
+
+NUM_BATCH_RETRIEVE_REVISIONID = 300
+
+def get_gitc_manifest_dir():
+  return wrapper.Wrapper().get_gitc_manifest_dir()
+
+def parse_clientdir(gitc_fs_path):
+  return wrapper.Wrapper().gitc_parse_clientdir(gitc_fs_path)
+
+def _set_project_revisions(projects):
+  """Sets the revisionExpr for a list of projects.
+
+  Because of the limit of open file descriptors allowed, length of projects
+  should not be overly large. Recommend calling this function multiple times
+  with each call not exceeding NUM_BATCH_RETRIEVE_REVISIONID projects.
+
+  @param projects: List of project objects to set the revionExpr for.
+  """
+  # Retrieve the commit id for each project based off of it's current
+  # revisionExpr and it is not already a commit id.
+  project_gitcmds = [(
+      project, git_command.GitCommand(None,
+                                      ['ls-remote',
+                                       project.remote.url,
+                                       project.revisionExpr],
+                                      capture_stdout=True, cwd='/tmp'))
+      for project in projects if not git_config.IsId(project.revisionExpr)]
+  for proj, gitcmd in project_gitcmds:
+    if gitcmd.Wait():
+      print('FATAL: Failed to retrieve revisionExpr for %s' % proj)
+      sys.exit(1)
+    proj.revisionExpr = gitcmd.stdout.split('\t')[0]
+
+def _manifest_groups(manifest):
+  """Returns the manifest group string that should be synced
+
+  This is the same logic used by Command.GetProjects(), which is used during
+  repo sync
+
+  @param manifest: The XmlManifest object
+  """
+  mp = manifest.manifestProject
+  groups = mp.config.GetString('manifest.groups')
+  if not groups:
+    groups = 'default,platform-' + platform.system().lower()
+  return groups
+
+def generate_gitc_manifest(gitc_manifest, manifest, paths=None):
+  """Generate a manifest for shafsd to use for this GITC client.
+
+  @param gitc_manifest: Current gitc manifest, or None if there isn't one yet.
+  @param manifest: A GitcManifest object loaded with the current repo manifest.
+  @param paths: List of project paths we want to update.
+  """
+
+  print('Generating GITC Manifest by fetching revision SHAs for each '
+        'project.')
+  if paths is None:
+    paths = manifest.paths.keys()
+
+  groups = [x for x in re.split(r'[,\s]+', _manifest_groups(manifest)) if x]
+
+  # Convert the paths to projects, and filter them to the matched groups.
+  projects = [manifest.paths[p] for p in paths]
+  projects = [p for p in projects if p.MatchesGroups(groups)]
+
+  if gitc_manifest is not None:
+    for path, proj in manifest.paths.iteritems():
+      if not proj.MatchesGroups(groups):
+        continue
+
+      if not proj.upstream and not git_config.IsId(proj.revisionExpr):
+        proj.upstream = proj.revisionExpr
+
+      if not path in gitc_manifest.paths:
+        # Any new projects need their first revision, even if we weren't asked
+        # for them.
+        projects.append(proj)
+      elif not path in paths:
+        # And copy revisions from the previous manifest if we're not updating
+        # them now.
+        gitc_proj = gitc_manifest.paths[path]
+        if gitc_proj.old_revision:
+          proj.revisionExpr = None
+          proj.old_revision = gitc_proj.old_revision
+        else:
+          proj.revisionExpr = gitc_proj.revisionExpr
+
+  index = 0
+  while index < len(projects):
+    _set_project_revisions(
+        projects[index:(index+NUM_BATCH_RETRIEVE_REVISIONID)])
+    index += NUM_BATCH_RETRIEVE_REVISIONID
+
+  if gitc_manifest is not None:
+    for path, proj in gitc_manifest.paths.iteritems():
+      if proj.old_revision and path in paths:
+        # If we updated a project that has been started, keep the old-revision
+        # updated.
+        repo_proj = manifest.paths[path]
+        repo_proj.old_revision = repo_proj.revisionExpr
+        repo_proj.revisionExpr = None
+
+  # Convert URLs from relative to absolute.
+  for name, remote in manifest.remotes.iteritems():
+    remote.fetchUrl = remote.resolvedFetchUrl
+
+  # Save the manifest.
+  save_manifest(manifest)
+
+def save_manifest(manifest, client_dir=None):
+  """Save the manifest file in the client_dir.
+
+  @param client_dir: Client directory to save the manifest in.
+  @param manifest: Manifest object to save.
+  """
+  if not client_dir:
+    client_dir = manifest.gitc_client_dir
+  with open(os.path.join(client_dir, '.manifest'), 'w') as f:
+    manifest.Save(f, groups=_manifest_groups(manifest))
+  # TODO(sbasi/jorg): Come up with a solution to remove the sleep below.
+  # Give the GITC filesystem time to register the manifest changes.
+  time.sleep(3)
diff --git a/hooks/commit-msg b/hooks/commit-msg
index d8f009b..40ac237 100755
--- a/hooks/commit-msg
+++ b/hooks/commit-msg
@@ -1,6 +1,7 @@
 #!/bin/sh
+# From Gerrit Code Review 2.12.1
 #
-# Part of Gerrit Code Review (http://code.google.com/p/gerrit/)
+# Part of Gerrit Code Review (https://www.gerritcodereview.com/)
 #
 # Copyright (C) 2009 The Android Open Source Project
 #
@@ -19,7 +20,7 @@
 
 unset GREP_OPTIONS
 
-CHANGE_ID_AFTER="Bug|Issue"
+CHANGE_ID_AFTER="Bug|Issue|Test"
 MSG="$1"
 
 # Check for, and add if missing, a unique Change-Id
@@ -38,6 +39,12 @@
 		return
 	fi
 
+	# Do not add Change-Id to temp commits
+	if echo "$clean_message" | head -1 | grep -q '^\(fixup\|squash\)!'
+	then
+		return
+	fi
+
 	if test "false" = "`git config --bool --get gerrit.createChangeId`"
 	then
 		return
@@ -57,6 +64,10 @@
 		AWK=/usr/xpg4/bin/awk
 	fi
 
+	# Get core.commentChar from git config or use default symbol
+	commentChar=`git config --get core.commentChar`
+	commentChar=${commentChar:-#}
+
 	# How this works:
 	# - parse the commit message as (textLine+ blankLine*)*
 	# - assume textLine+ to be a footer until proven otherwise
@@ -75,8 +86,8 @@
 		blankLines = 0
 	}
 
-	# Skip lines starting with "#" without any spaces before it.
-	/^#/ { next }
+	# Skip lines starting with commentChar without any spaces before it.
+	/^'"$commentChar"'/ { next }
 
 	# Skip the line starting with the diff command and everything after it,
 	# up to the end of the file, assuming it is only patch data.
diff --git a/main.py b/main.py
index 6736abc..4f4eb9f 100755
--- a/main.py
+++ b/main.py
@@ -42,6 +42,7 @@
 from git_config import init_ssh, close_ssh
 from command import InteractiveCommand
 from command import MirrorSafeCommand
+from command import GitcAvailableCommand, GitcClientCommand
 from subcmds.version import Version
 from editor import Editor
 from error import DownloadError
@@ -51,7 +52,8 @@
 from error import NoManifestException
 from error import NoSuchProjectError
 from error import RepoChangedException
-from manifest_xml import XmlManifest
+import gitc_utils
+from manifest_xml import GitcManifest, XmlManifest
 from pager import RunPager
 from wrapper import WrapperPath, Wrapper
 
@@ -129,6 +131,12 @@
 
     cmd.repodir = self.repodir
     cmd.manifest = XmlManifest(cmd.repodir)
+    cmd.gitc_manifest = None
+    gitc_client_name = gitc_utils.parse_clientdir(os.getcwd())
+    if gitc_client_name:
+      cmd.gitc_manifest = GitcManifest(cmd.repodir, gitc_client_name)
+      cmd.manifest.isGitcClient = True
+
     Editor.globalConfig = cmd.manifest.globalConfig
 
     if not isinstance(cmd, MirrorSafeCommand) and cmd.manifest.IsMirror:
@@ -136,6 +144,16 @@
             file=sys.stderr)
       return 1
 
+    if isinstance(cmd, GitcAvailableCommand) and not gitc_utils.get_gitc_manifest_dir():
+      print("fatal: '%s' requires GITC to be available" % name,
+            file=sys.stderr)
+      return 1
+
+    if isinstance(cmd, GitcClientCommand) and not gitc_client_name:
+      print("fatal: '%s' requires a GITC client" % name,
+            file=sys.stderr)
+      return 1
+
     try:
       copts, cargs = cmd.OptionParser.parse_args(argv)
       copts = cmd.ReadEnvironmentOptions(copts)
diff --git a/manifest_xml.py b/manifest_xml.py
index 7e71960..3ac607e 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -29,6 +29,7 @@
   urllib = imp.new_module('urllib')
   urllib.parse = urlparse
 
+import gitc_utils
 from git_config import GitConfig
 from git_refs import R_HEADS, HEAD
 from project import RemoteSpec, Project, MetaProject
@@ -112,6 +113,7 @@
     self.manifestFile = os.path.join(self.repodir, MANIFEST_FILE_NAME)
     self.globalConfig = GitConfig.ForUser()
     self.localManifestWarning = False
+    self.isGitcClient = False
 
     self.repoProject = MetaProject(self, 'repo',
       gitdir   = os.path.join(repodir, 'repo/.git'),
@@ -165,12 +167,13 @@
   def _ParseGroups(self, groups):
     return [x for x in re.split(r'[,\s]+', groups) if x]
 
-  def Save(self, fd, peg_rev=False, peg_rev_upstream=True):
+  def Save(self, fd, peg_rev=False, peg_rev_upstream=True, groups=None):
     """Write the current manifest out to the given file descriptor.
     """
     mp = self.manifestProject
 
-    groups = mp.config.GetString('manifest.groups')
+    if groups is None:
+      groups = mp.config.GetString('manifest.groups')
     if groups:
       groups = self._ParseGroups(groups)
 
@@ -303,6 +306,11 @@
       if p.sync_s:
         e.setAttribute('sync-s', 'true')
 
+      if p.clone_depth:
+        e.setAttribute('clone-depth', str(p.clone_depth))
+
+      self._output_manifest_project_extras(p, e)
+
       if p.subprojects:
         subprojects = set(subp.name for subp in p.subprojects)
         output_projects(p, e, list(sorted(subprojects)))
@@ -320,6 +328,10 @@
 
     doc.writexml(fd, '', '  ', '\n', 'UTF-8')
 
+  def _output_manifest_project_extras(self, p, e):
+    """Manifests can modify e if they support extra project attributes."""
+    pass
+
   @property
   def paths(self):
     self._Load()
@@ -709,7 +721,7 @@
   def _UnjoinName(self, parent_name, name):
     return os.path.relpath(name, parent_name)
 
-  def _ParseProject(self, node, parent = None):
+  def _ParseProject(self, node, parent = None, **extra_proj_attrs):
     """
     reads a <project> element from the manifest file
     """
@@ -804,7 +816,8 @@
                       clone_depth = clone_depth,
                       upstream = upstream,
                       parent = parent,
-                      dest_branch = dest_branch)
+                      dest_branch = dest_branch,
+                      **extra_proj_attrs)
 
     for n in node.childNodes:
       if n.nodeName == 'copyfile':
@@ -935,3 +948,26 @@
       diff['added'].append(toProjects[proj])
 
     return diff
+
+
+class GitcManifest(XmlManifest):
+
+  def __init__(self, repodir, gitc_client_name):
+    """Initialize the GitcManifest object."""
+    super(GitcManifest, self).__init__(repodir)
+    self.isGitcClient = True
+    self.gitc_client_name = gitc_client_name
+    self.gitc_client_dir = os.path.join(gitc_utils.get_gitc_manifest_dir(),
+                                        gitc_client_name)
+    self.manifestFile = os.path.join(self.gitc_client_dir, '.manifest')
+
+  def _ParseProject(self, node, parent = None):
+    """Override _ParseProject and add support for GITC specific attributes."""
+    return super(GitcManifest, self)._ParseProject(
+        node, parent=parent, old_revision=node.getAttribute('old-revision'))
+
+  def _output_manifest_project_extras(self, p, e):
+    """Output GITC Specific Project attributes"""
+    if p.old_revision:
+        e.setAttribute('old-revision', str(p.old_revision))
+
diff --git a/project.py b/project.py
index a117f4d..e3c3bd5 100644
--- a/project.py
+++ b/project.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 
 from __future__ import print_function
-import contextlib
 import errno
 import filecmp
 import glob
@@ -31,7 +30,8 @@
 
 from color import Coloring
 from git_command import GitCommand, git_require
-from git_config import GitConfig, IsId, GetSchemeFromUrl, ID_RE
+from git_config import GitConfig, IsId, GetSchemeFromUrl, GetUrlCookieFile, \
+    ID_RE
 from error import GitError, HookError, UploadError, DownloadError
 from error import ManifestInvalidRevisionError
 from error import NoManifestException
@@ -45,6 +45,7 @@
   input = raw_input
   # pylint:enable=W0622
 
+
 def _lwrite(path, content):
   lock = '%s.lock' % path
 
@@ -60,17 +61,27 @@
     os.remove(lock)
     raise
 
+
 def _error(fmt, *args):
   msg = fmt % args
   print('error: %s' % msg, file=sys.stderr)
 
+
+def _warn(fmt, *args):
+  msg = fmt % args
+  print('warn: %s' % msg, file=sys.stderr)
+
+
 def not_rev(r):
   return '^' + r
 
+
 def sq(r):
   return "'" + r.replace("'", "'\''") + "'"
 
 _project_hook_list = None
+
+
 def _ProjectHooks():
   """List the hooks present in the 'hooks' directory.
 
@@ -104,15 +115,14 @@
   @property
   def commits(self):
     if self._commit_cache is None:
-      self._commit_cache = self.project.bare_git.rev_list(
-        '--abbrev=8',
-        '--abbrev-commit',
-        '--pretty=oneline',
-        '--reverse',
-        '--date-order',
-        not_rev(self.base),
-        self.commit,
-        '--')
+      self._commit_cache = self.project.bare_git.rev_list('--abbrev=8',
+                                                          '--abbrev-commit',
+                                                          '--pretty=oneline',
+                                                          '--reverse',
+                                                          '--date-order',
+                                                          not_rev(self.base),
+                                                          self.commit,
+                                                          '--')
     return self._commit_cache
 
 
@@ -131,36 +141,36 @@
   @property
   def commits(self):
     if self._commit_cache is None:
-      self._commit_cache = self.project.bare_git.rev_list(
-        '--abbrev=8',
-        '--abbrev-commit',
-        '--pretty=oneline',
-        '--reverse',
-        '--date-order',
-        not_rev(self.base),
-        R_HEADS + self.name,
-        '--')
+      self._commit_cache = self.project.bare_git.rev_list('--abbrev=8',
+                                                          '--abbrev-commit',
+                                                          '--pretty=oneline',
+                                                          '--reverse',
+                                                          '--date-order',
+                                                          not_rev(self.base),
+                                                          R_HEADS + self.name,
+                                                          '--')
     return self._commit_cache
 
   @property
   def unabbrev_commits(self):
     r = dict()
-    for commit in self.project.bare_git.rev_list(
-        not_rev(self.base),
-        R_HEADS + self.name,
-        '--'):
+    for commit in self.project.bare_git.rev_list(not_rev(self.base),
+                                                 R_HEADS + self.name,
+                                                 '--'):
       r[commit[0:8]] = commit
     return r
 
   @property
   def date(self):
-    return self.project.bare_git.log(
-      '--pretty=format:%cd',
-      '-n', '1',
-      R_HEADS + self.name,
-      '--')
+    return self.project.bare_git.log('--pretty=format:%cd',
+                                     '-n', '1',
+                                     R_HEADS + self.name,
+                                     '--')
 
-  def UploadForReview(self, people, auto_topic=False, draft=False, dest_branch=None):
+  def UploadForReview(self, people,
+                      auto_topic=False,
+                      draft=False,
+                      dest_branch=None):
     self.project.UploadForReview(self.name,
                                  people,
                                  auto_topic=auto_topic,
@@ -170,8 +180,8 @@
   def GetPublishedRefs(self):
     refs = {}
     output = self.project.bare_git.ls_remote(
-      self.branch.remote.SshReviewUrl(self.project.UserEmail),
-      'refs/changes/*')
+        self.branch.remote.SshReviewUrl(self.project.UserEmail),
+        'refs/changes/*')
     for line in output.split('\n'):
       try:
         (sha, ref) = line.split()
@@ -181,7 +191,9 @@
 
     return refs
 
+
 class StatusColoring(Coloring):
+
   def __init__(self, config):
     Coloring.__init__(self, config, 'status')
     self.project = self.printer('header', attr='bold')
@@ -195,17 +207,22 @@
 
 
 class DiffColoring(Coloring):
+
   def __init__(self, config):
     Coloring.__init__(self, config, 'diff')
     self.project = self.printer('header', attr='bold')
 
+
 class _Annotation(object):
+
   def __init__(self, name, value, keep):
     self.name = name
     self.value = value
     self.keep = keep
 
+
 class _CopyFile(object):
+
   def __init__(self, src, dest, abssrc, absdest):
     self.src = src
     self.dest = dest
@@ -233,7 +250,9 @@
       except IOError:
         _error('Cannot copy file %s to %s', src, dest)
 
+
 class _LinkFile(object):
+
   def __init__(self, git_worktree, src, dest, relsrc, absdest):
     self.git_worktree = git_worktree
     self.src = src
@@ -246,7 +265,7 @@
     if not os.path.islink(absDest) or (os.readlink(absDest) != relSrc):
       try:
         # remove existing file first, since it might be read-only
-        if os.path.exists(absDest):
+        if os.path.lexists(absDest):
           os.remove(absDest)
         else:
           dest_dir = os.path.dirname(absDest)
@@ -272,7 +291,7 @@
       absDestDir = self.abs_dest
       if os.path.exists(absDestDir) and not os.path.isdir(absDestDir):
         _error('Link error: src with wildcard, %s must be a directory',
-            absDestDir)
+               absDestDir)
       else:
         absSrcFiles = glob.glob(absSrc)
         for absSrcFile in absSrcFiles:
@@ -289,7 +308,9 @@
           relSrc = os.path.join(relSrcDir, srcFile)
           self.__linkIt(relSrc, absDest)
 
+
 class RemoteSpec(object):
+
   def __init__(self,
                name,
                url=None,
@@ -300,7 +321,9 @@
     self.review = review
     self.revision = revision
 
+
 class RepoHook(object):
+
   """A RepoHook contains information about a script to run as a hook.
 
   Hooks are used to run a python script before running an upload (for instance,
@@ -313,6 +336,7 @@
   Hooks are always python.  When a hook is run, we will load the hook into the
   interpreter and execute its main() function.
   """
+
   def __init__(self,
                hook_type,
                hooks_project,
@@ -427,8 +451,8 @@
                  '  %s\n'
                  '\n'
                  'Do you want to allow this script to run '
-                 '(yes/yes-never-ask-again/NO)? ') % (
-                 self._GetMustVerb(), self._script_fullpath)
+                 '(yes/yes-never-ask-again/NO)? ') % (self._GetMustVerb(),
+                                                      self._script_fullpath)
       response = input(prompt).lower()
       print()
 
@@ -472,19 +496,18 @@
 
       # Exec, storing global context in the context dict.  We catch exceptions
       # and  convert to a HookError w/ just the failing traceback.
-      context = {}
+      context = {'__file__': self._script_fullpath}
       try:
         exec(compile(open(self._script_fullpath).read(),
                      self._script_fullpath, 'exec'), context)
       except Exception:
-        raise HookError('%s\nFailed to import %s hook; see traceback above.' % (
-                        traceback.format_exc(), self._hook_type))
+        raise HookError('%s\nFailed to import %s hook; see traceback above.' %
+                        (traceback.format_exc(), self._hook_type))
 
       # Running the script should have defined a main() function.
       if 'main' not in context:
         raise HookError('Missing main() in: "%s"' % self._script_fullpath)
 
-
       # Add 'hook_should_take_kwargs' to the arguments to be passed to main.
       # We don't actually want hooks to define their main with this argument--
       # it's there to remind them that their hook should always take **kwargs.
@@ -502,8 +525,8 @@
         context['main'](**kwargs)
       except Exception:
         raise HookError('%s\nFailed to run main() for %s hook; see traceback '
-                        'above.' % (
-                        traceback.format_exc(), self._hook_type))
+                        'above.' % (traceback.format_exc(),
+                                    self._hook_type))
     finally:
       # Restore sys.path and CWD.
       sys.path = orig_syspath
@@ -527,8 +550,8 @@
           to run a required hook (from _CheckForHookApproval).
     """
     # No-op if there is no hooks project or if hook is disabled.
-    if ((not self._hooks_project) or
-        (self._hook_type not in self._hooks_project.enabled_repo_hooks)):
+    if ((not self._hooks_project) or (self._hook_type not in
+                                      self._hooks_project.enabled_repo_hooks)):
       return
 
     # Bail with a nice error if we can't find the hook.
@@ -550,6 +573,7 @@
   # These objects can only be used by a single working tree.
   working_tree_files = ['config', 'packed-refs', 'shallow']
   working_tree_dirs = ['logs', 'refs']
+
   def __init__(self,
                manifest,
                name,
@@ -569,7 +593,8 @@
                parent=None,
                is_derived=False,
                dest_branch=None,
-               optimized_fetch=False):
+               optimized_fetch=False,
+               old_revision=None):
     """Init a Project object.
 
     Args:
@@ -593,6 +618,7 @@
       dest_branch: The branch to which to push changes for review by default.
       optimized_fetch: If True, when a project is set to a sha1 revision, only
                        fetch from the remote if the sha1 is not present locally.
+      old_revision: saved git commit id for open GITC projects.
     """
     self.manifest = manifest
     self.name = name
@@ -606,9 +632,9 @@
     self.relpath = relpath
     self.revisionExpr = revisionExpr
 
-    if   revisionId is None \
-     and revisionExpr \
-     and IsId(revisionExpr):
+    if revisionId is None \
+            and revisionExpr \
+            and IsId(revisionExpr):
       self.revisionId = revisionExpr
     else:
       self.revisionId = revisionId
@@ -628,9 +654,8 @@
     self.copyfiles = []
     self.linkfiles = []
     self.annotations = []
-    self.config = GitConfig.ForRepository(
-                    gitdir=self.gitdir,
-                    defaults=self.manifest.globalConfig)
+    self.config = GitConfig.ForRepository(gitdir=self.gitdir,
+                                          defaults=self.manifest.globalConfig)
 
     if self.worktree:
       self.work_git = self._GitGetByExec(self, bare=False, gitdir=gitdir)
@@ -640,6 +665,7 @@
     self.bare_ref = GitRefs(gitdir)
     self.bare_objdir = self._GitGetByExec(self, bare=True, gitdir=objdir)
     self.dest_branch = dest_branch
+    self.old_revision = old_revision
 
     # This will be filled in if a project is later identified to be the
     # project containing repo hooks.
@@ -767,7 +793,7 @@
     """
     expanded_manifest_groups = manifest_groups or ['default']
     expanded_project_groups = ['all'] + (self.groups or [])
-    if not 'notdefault' in expanded_project_groups:
+    if 'notdefault' not in expanded_project_groups:
       expanded_project_groups += ['default']
 
     matched = False
@@ -779,7 +805,7 @@
 
     return matched
 
-## Status Display ##
+# Status Display ##
   def UncommitedFiles(self, get_all=True):
     """Returns a list of strings, uncommitted files in the git tree.
 
@@ -831,7 +857,7 @@
       output: If specified, redirect the output to this object.
     """
     if not os.path.isdir(self.worktree):
-      if output_redir == None:
+      if output_redir is None:
         output_redir = sys.stdout
       print(file=output_redir)
       print('project %s/' % self.relpath, file=output_redir)
@@ -850,7 +876,7 @@
       return 'CLEAN'
 
     out = StatusColoring(self.config)
-    if not output_redir == None:
+    if output_redir is not None:
       out.redirect(output_redir)
     out.project('project %-40s', self.relpath + '/ ')
 
@@ -893,7 +919,7 @@
 
       if i and i.src_path:
         line = ' %s%s\t%s => %s (%s%%)' % (i_status, f_status,
-                                        i.src_path, p, i.level)
+                                           i.src_path, p, i.level)
       else:
         line = ' %s%s\t%s' % (i_status, f_status, p)
 
@@ -936,7 +962,7 @@
     p.Wait()
 
 
-## Publish / Upload ##
+# Publish / Upload ##
 
   def WasPublished(self, branch, all_refs=None):
     """Was the branch published (uploaded) for code review?
@@ -1079,7 +1105,7 @@
                             message=msg)
 
 
-## Sync ##
+# Sync ##
 
   def _ExtractArchive(self, tarpath, path=None):
     """Extract the given tar on its current location
@@ -1093,26 +1119,25 @@
         tar.extractall(path=path)
         return True
     except (IOError, tarfile.TarError) as e:
-      print("error: Cannot extract archive %s: "
-            "%s" % (tarpath, str(e)), file=sys.stderr)
+      _error("Cannot extract archive %s: %s", tarpath, str(e))
     return False
 
   def Sync_NetworkHalf(self,
-      quiet=False,
-      is_new=None,
-      current_branch_only=False,
-      force_sync=False,
-      clone_bundle=True,
-      no_tags=False,
-      archive=False,
-      optimized_fetch=False):
+                       quiet=False,
+                       is_new=None,
+                       current_branch_only=False,
+                       force_sync=False,
+                       clone_bundle=True,
+                       no_tags=False,
+                       archive=False,
+                       optimized_fetch=False,
+                       prune=False):
     """Perform only the network IO portion of the sync process.
        Local working directory/branch state is not affected.
     """
     if archive and not isinstance(self, MetaProject):
       if self.remote.url.startswith(('http://', 'https://')):
-        print("error: %s: Cannot fetch archives from http/https "
-              "remotes." % self.name, file=sys.stderr)
+        _error("%s: Cannot fetch archives from http/https remotes.", self.name)
         return False
 
       name = self.relpath.replace('\\', '/')
@@ -1123,7 +1148,7 @@
       try:
         self._FetchArchive(tarpath, cwd=topdir)
       except GitError as e:
-        print('error: %s' % str(e), file=sys.stderr)
+        _error('%s', e)
         return False
 
       # From now on, we only need absolute tarpath
@@ -1134,8 +1159,7 @@
       try:
         os.remove(tarpath)
       except OSError as e:
-        print("warn: Cannot remove archive %s: "
-              "%s" % (tarpath, str(e)), file=sys.stderr)
+        _warn("Cannot remove archive %s: %s", tarpath, str(e))
       self._CopyAndLinkFiles()
       return True
     if is_new is None:
@@ -1160,8 +1184,8 @@
       alt_dir = None
 
     if clone_bundle \
-    and alt_dir is None \
-    and self._ApplyCloneBundle(initial=is_new, quiet=quiet):
+            and alt_dir is None \
+            and self._ApplyCloneBundle(initial=is_new, quiet=quiet):
       is_new = False
 
     if not current_branch_only:
@@ -1173,12 +1197,13 @@
       elif self.manifest.default.sync_c:
         current_branch_only = True
 
-    need_to_fetch = not (optimized_fetch and \
-      (ID_RE.match(self.revisionExpr) and self._CheckForSha1()))
-    if (need_to_fetch
-        and not self._RemoteFetch(initial=is_new, quiet=quiet, alt_dir=alt_dir,
-                                  current_branch_only=current_branch_only,
-                                  no_tags=no_tags)):
+    need_to_fetch = not (optimized_fetch and
+                         (ID_RE.match(self.revisionExpr) and
+                          self._CheckForSha1()))
+    if (need_to_fetch and
+        not self._RemoteFetch(initial=is_new, quiet=quiet, alt_dir=alt_dir,
+                              current_branch_only=current_branch_only,
+                              no_tags=no_tags, prune=prune)):
       return False
 
     if self.worktree:
@@ -1195,6 +1220,8 @@
     self._InitHooks()
 
   def _CopyAndLinkFiles(self):
+    if self.manifest.isGitcClient:
+      return
     for copyfile in self.copyfiles:
       copyfile._Copy()
     for linkfile in self.linkfiles:
@@ -1213,9 +1240,8 @@
     try:
       return self.bare_git.rev_list(self.revisionExpr, '-1')[0]
     except GitError:
-      raise ManifestInvalidRevisionError(
-        'revision %s in %s not found' % (self.revisionExpr,
-                                         self.name))
+      raise ManifestInvalidRevisionError('revision %s in %s not found' %
+                                         (self.revisionExpr, self.name))
 
   def GetRevisionId(self, all_refs=None):
     if self.revisionId:
@@ -1230,9 +1256,8 @@
     try:
       return self.bare_git.rev_parse('--verify', '%s^0' % rev)
     except GitError:
-      raise ManifestInvalidRevisionError(
-        'revision %s in %s not found' % (self.revisionExpr,
-                                         self.name))
+      raise ManifestInvalidRevisionError('revision %s in %s not found' %
+                                         (self.revisionExpr, self.name))
 
   def Sync_LocalHalf(self, syncbuf, force_sync=False):
     """Perform only the local IO portion of the sync process.
@@ -1270,6 +1295,8 @@
         # Except if the head needs to be detached
         #
         if not syncbuf.detach_head:
+          # The copy/linkfile config may have changed.
+          self._CopyAndLinkFiles()
           return
       else:
         lost = self._revlist(not_rev(revid), HEAD)
@@ -1287,6 +1314,8 @@
     if head == revid:
       # No changes; don't do anything further.
       #
+      # The copy/linkfile config may have changed.
+      self._CopyAndLinkFiles()
       return
 
     branch = self.GetBranch(branch)
@@ -1317,8 +1346,8 @@
           # to rewrite the published commits so we punt.
           #
           syncbuf.fail(self,
-                       "branch %s is published (but not merged) and is now %d commits behind"
-                       % (branch.name, len(upstream_gain)))
+                       "branch %s is published (but not merged) and is now "
+                       "%d commits behind" % (branch.name, len(upstream_gain)))
         return
       elif pub == head:
         # All published commits are merged, and thus we are a
@@ -1412,7 +1441,7 @@
     remote = self.GetRemote(self.remote.name)
 
     cmd = ['fetch', remote.name]
-    cmd.append('refs/changes/%2.2d/%d/%d' \
+    cmd.append('refs/changes/%2.2d/%d/%d'
                % (change_id % 100, change_id, patch_id))
     if GitCommand(self, cmd, bare=True).Wait() != 0:
       return None
@@ -1423,11 +1452,13 @@
                             self.bare_git.rev_parse('FETCH_HEAD'))
 
 
-## Branch Management ##
+# Branch Management ##
 
-  def StartBranch(self, name):
+  def StartBranch(self, name, branch_merge=''):
     """Create a new branch off the manifest's revision.
     """
+    if not branch_merge:
+      branch_merge = self.revisionExpr
     head = self.work_git.GetHead()
     if head == (R_HEADS + name):
       return True
@@ -1441,9 +1472,9 @@
 
     branch = self.GetBranch(name)
     branch.remote = self.GetRemote(self.remote.name)
-    branch.merge = self.revisionExpr
-    if not branch.merge.startswith('refs/') and not ID_RE.match(self.revisionExpr):
-      branch.merge = R_HEADS + self.revisionExpr
+    branch.merge = branch_merge
+    if not branch.merge.startswith('refs/') and not ID_RE.match(branch_merge):
+      branch.merge = R_HEADS + branch_merge
     revid = self.GetRevisionId(all_refs)
 
     if head.startswith(R_HEADS):
@@ -1451,7 +1482,6 @@
         head = all_refs[head]
       except KeyError:
         head = None
-
     if revid and head and revid == head:
       ref = os.path.join(self.gitdir, R_HEADS + name)
       try:
@@ -1572,8 +1602,6 @@
 
     if kill:
       old = self.bare_git.GetHead()
-      if old is None:
-        old = 'refs/heads/please_never_use_this_as_a_branch_name'
 
       try:
         self.bare_git.DetachHead(rev)
@@ -1585,7 +1613,10 @@
                        capture_stderr=True)
         b.Wait()
       finally:
-        self.bare_git.SetHead(old)
+        if ID_RE.match(old):
+          self.bare_git.DetachHead(old)
+        else:
+          self.bare_git.SetHead(old)
         left = self._allrefs
 
       for branch in kill:
@@ -1608,10 +1639,11 @@
     return kept
 
 
-## Submodule Management ##
+# Submodule Management ##
 
   def GetRegisteredSubprojects(self):
     result = []
+
     def rec(subprojects):
       if not subprojects:
         return
@@ -1646,6 +1678,7 @@
 
     re_path = re.compile(r'^submodule\.([^.]+)\.path=(.*)$')
     re_url = re.compile(r'^submodule\.([^.]+)\.url=(.*)$')
+
     def parse_gitmodules(gitdir, rev):
       cmd = ['cat-file', 'blob', '%s:.gitmodules' % rev]
       try:
@@ -1755,7 +1788,7 @@
     return result
 
 
-## Direct Git Commands ##
+# Direct Git Commands ##
   def _CheckForSha1(self):
     try:
       # if revision (sha or tag) is not present then following function
@@ -1779,13 +1812,13 @@
     if command.Wait() != 0:
       raise GitError('git archive %s: %s' % (self.name, command.stderr))
 
-
   def _RemoteFetch(self, name=None,
                    current_branch_only=False,
                    initial=False,
                    quiet=False,
                    alt_dir=None,
-                   no_tags=False):
+                   no_tags=False,
+                   prune=False):
 
     is_sha1 = False
     tag_name = None
@@ -1898,6 +1931,9 @@
     else:
       cmd.append('--tags')
 
+    if prune:
+      cmd.append('--prune')
+
     spec = []
     if not current_branch_only:
       # Fetch whole repo
@@ -1939,9 +1975,9 @@
           break
         continue
       elif current_branch_only and is_sha1 and ret == 128:
-        # Exit code 128 means "couldn't find the ref you asked for"; if we're in sha1
-        # mode, we just tried sync'ing from the upstream field; it doesn't exist, thus
-        # abort the optimization attempt and do a full sync.
+        # Exit code 128 means "couldn't find the ref you asked for"; if we're
+        # in sha1 mode, we just tried sync'ing from the upstream field; it
+        # doesn't exist, thus abort the optimization attempt and do a full sync.
         break
       elif ret < 0:
         # Git died with a signal, exit immediately
@@ -1968,20 +2004,24 @@
                                    initial=False, quiet=quiet, alt_dir=alt_dir)
         if self.clone_depth:
           self.clone_depth = None
-          return self._RemoteFetch(name=name, current_branch_only=current_branch_only,
+          return self._RemoteFetch(name=name,
+                                   current_branch_only=current_branch_only,
                                    initial=False, quiet=quiet, alt_dir=alt_dir)
 
     return ok
 
   def _ApplyCloneBundle(self, initial=False, quiet=False):
-    if initial and (self.manifest.manifestProject.config.GetString('repo.depth') or self.clone_depth):
+    if initial and \
+        (self.manifest.manifestProject.config.GetString('repo.depth') or
+         self.clone_depth):
       return False
 
     remote = self.GetRemote(self.remote.name)
     bundle_url = remote.url + '/clone.bundle'
     bundle_url = GitConfig.ForUser().UrlInsteadOf(bundle_url)
-    if GetSchemeFromUrl(bundle_url) not in (
-        'http', 'https', 'persistent-http', 'persistent-https'):
+    if GetSchemeFromUrl(bundle_url) not in ('http', 'https',
+                                            'persistent-http',
+                                            'persistent-https'):
       return False
 
     bundle_dst = os.path.join(self.gitdir, 'clone.bundle')
@@ -2030,7 +2070,7 @@
         os.remove(tmpPath)
     if 'http_proxy' in os.environ and 'darwin' == sys.platform:
       cmd += ['--proxy', os.environ['http_proxy']]
-    with self._GetBundleCookieFile(srcUrl, quiet) as cookiefile:
+    with GetUrlCookieFile(srcUrl, quiet) as (cookiefile, _proxy):
       if cookiefile:
         cmd += ['--cookie', cookiefile, '--cookie-jar', cookiefile]
       if srcUrl.startswith('persistent-'):
@@ -2078,40 +2118,6 @@
     except OSError:
       return False
 
-  @contextlib.contextmanager
-  def _GetBundleCookieFile(self, url, quiet):
-    if url.startswith('persistent-'):
-      try:
-        p = subprocess.Popen(
-            ['git-remote-persistent-https', '-print_config', url],
-            stdin=subprocess.PIPE, stdout=subprocess.PIPE,
-            stderr=subprocess.PIPE)
-        try:
-          prefix = 'http.cookiefile='
-          cookiefile = None
-          for line in p.stdout:
-            line = line.strip()
-            if line.startswith(prefix):
-              cookiefile = line[len(prefix):]
-              break
-          # Leave subprocess open, as cookie file may be transient.
-          if cookiefile:
-            yield cookiefile
-            return
-        finally:
-          p.stdin.close()
-          if p.wait():
-            err_msg = p.stderr.read()
-            if ' -print_config' in err_msg:
-              pass  # Persistent proxy doesn't support -print_config.
-            elif not quiet:
-              print(err_msg, file=sys.stderr)
-      except OSError as e:
-        if e.errno == errno.ENOENT:
-          pass  # No persistent proxy.
-        raise
-    yield GitConfig.ForUser().GetString('http.cookiefile')
-
   def _Checkout(self, rev, quiet=False):
     cmd = ['checkout']
     if quiet:
@@ -2182,12 +2188,13 @@
         try:
           self._CheckDirReference(self.objdir, self.gitdir, share_refs=False)
         except GitError as e:
-          print("Retrying clone after deleting %s" % force_sync, file=sys.stderr)
           if force_sync:
+            print("Retrying clone after deleting %s" %
+                  self.gitdir, file=sys.stderr)
             try:
               shutil.rmtree(os.path.realpath(self.gitdir))
-              if self.worktree and os.path.exists(
-                  os.path.realpath(self.worktree)):
+              if self.worktree and os.path.exists(os.path.realpath
+                                                  (self.worktree)):
                 shutil.rmtree(os.path.realpath(self.worktree))
               return self._InitGitDir(mirror_git=mirror_git, force_sync=False)
             except:
@@ -2246,7 +2253,7 @@
       name = os.path.basename(stock_hook)
 
       if name in ('commit-msg',) and not self.remote.review \
-            and not self is self.manifest.manifestProject:
+              and self is not self.manifest.manifestProject:
         # Don't install a Gerrit Code Review hook if this
         # project does not appear to use it for reviews.
         #
@@ -2261,7 +2268,8 @@
         if filecmp.cmp(stock_hook, dst, shallow=False):
           os.remove(dst)
         else:
-          _error("%s: Not replacing %s hook", self.relpath, name)
+          _warn("%s: Not replacing locally modified %s hook",
+                self.relpath, name)
           continue
       try:
         os.symlink(os.path.relpath(stock_hook, os.path.dirname(dst)), dst)
@@ -2320,7 +2328,10 @@
         # Fail if the links are pointing to the wrong place
         if src != dst:
           raise GitError('--force-sync not enabled; cannot overwrite a local '
-                         'work tree')
+                         'work tree. If you\'re comfortable with the '
+                         'possibility of losing the work tree\'s git metadata,'
+                         ' use `repo sync --force-sync {0}` to '
+                         'proceed.'.format(self.relpath))
 
   def _ReferenceGitDir(self, gitdir, dotgit, share_refs, copy_all):
     """Update |dotgit| to reference |gitdir|, using symlinks where possible.
@@ -2464,6 +2475,7 @@
     return logs
 
   class _GitGetByExec(object):
+
     def __init__(self, project, bare, gitdir):
       self._project = project
       self._bare = bare
@@ -2482,8 +2494,8 @@
       if p.Wait() == 0:
         out = p.stdout
         if out:
+          # Backslash is not anomalous
           return out[:-1].split('\0')  # pylint: disable=W1401
-                                       # Backslash is not anomalous
       return []
 
     def DiffZ(self, name, *args):
@@ -2509,6 +2521,7 @@
               break
 
             class _Info(object):
+
               def __init__(self, path, omode, nmode, oid, nid, state):
                 self.path = path
                 self.src_path = None
@@ -2611,10 +2624,8 @@
           line = line[:-1]
         r.append(line)
       if p.Wait() != 0:
-        raise GitError('%s rev-list %s: %s' % (
-                       self._project.name,
-                       str(args),
-                       p.stderr))
+        raise GitError('%s rev-list %s: %s' %
+                       (self._project.name, str(args), p.stderr))
       return r
 
     def __getattr__(self, name):
@@ -2637,6 +2648,7 @@
         A callable object that will try to call git with the named command.
       """
       name = name.replace('_', '-')
+
       def runner(*args, **kwargs):
         cmdv = []
         config = kwargs.pop('config', None)
@@ -2659,10 +2671,8 @@
                        capture_stdout=True,
                        capture_stderr=True)
         if p.Wait() != 0:
-          raise GitError('%s %s: %s' % (
-                         self._project.name,
-                         name,
-                         p.stderr))
+          raise GitError('%s %s: %s' %
+                         (self._project.name, name, p.stderr))
         r = p.stdout
         try:
           r = r.decode('utf-8')
@@ -2675,14 +2685,19 @@
 
 
 class _PriorSyncFailedError(Exception):
+
   def __str__(self):
     return 'prior sync failed; rebase still in progress'
 
+
 class _DirtyError(Exception):
+
   def __str__(self):
     return 'contains uncommitted changes'
 
+
 class _InfoMessage(object):
+
   def __init__(self, project, text):
     self.project = project
     self.text = text
@@ -2691,7 +2706,9 @@
     syncbuf.out.info('%s/: %s', self.project.relpath, self.text)
     syncbuf.out.nl()
 
+
 class _Failure(object):
+
   def __init__(self, project, why):
     self.project = project
     self.why = why
@@ -2702,7 +2719,9 @@
                      str(self.why))
     syncbuf.out.nl()
 
+
 class _Later(object):
+
   def __init__(self, project, action):
     self.project = project
     self.action = action
@@ -2719,14 +2738,18 @@
       out.nl()
       return False
 
+
 class _SyncColoring(Coloring):
+
   def __init__(self, config):
     Coloring.__init__(self, config, 'reposync')
     self.project = self.printer('header', attr='bold')
     self.info = self.printer('info')
     self.fail = self.printer('fail', fg='red')
 
+
 class SyncBuffer(object):
+
   def __init__(self, config, detach_head=False):
     self._messages = []
     self._failures = []
@@ -2782,8 +2805,10 @@
 
 
 class MetaProject(Project):
+
   """A special project housed under .repo.
   """
+
   def __init__(self, manifest, name, gitdir, worktree):
     Project.__init__(self,
                      manifest=manifest,
@@ -2817,10 +2842,9 @@
     syncbuf.Finish()
 
     return GitCommand(self,
-                        ['update-ref', '-d', 'refs/heads/default'],
-                        capture_stdout=True,
-                        capture_stderr=True).Wait() == 0
-
+                      ['update-ref', '-d', 'refs/heads/default'],
+                      capture_stdout=True,
+                      capture_stderr=True).Wait() == 0
 
   @property
   def LastFetch(self):
diff --git a/repo b/repo
index 7769565..e5cb890 100755
--- a/repo
+++ b/repo
@@ -1,8 +1,11 @@
 #!/usr/bin/env python
 
-## repo default configuration
-##
-REPO_URL = 'https://gerrit.googlesource.com/git-repo'
+# repo default configuration
+#
+import os
+REPO_URL = os.environ.get('REPO_URL', None)
+if not REPO_URL:
+  REPO_URL = 'https://gerrit.googlesource.com/git-repo'
 REPO_REV = 'stable'
 
 # Copyright (C) 2008 Google Inc.
@@ -20,7 +23,7 @@
 # limitations under the License.
 
 # increment this whenever we make important changes to this script
-VERSION = (1, 21)
+VERSION = (1, 22)
 
 # increment this if the MAINTAINER_KEYS block is modified
 KEYRING_VERSION = (1, 2)
@@ -101,18 +104,19 @@
 -----END PGP PUBLIC KEY BLOCK-----
 """
 
-GIT = 'git'                     # our git command
-MIN_GIT_VERSION = (1, 7, 2)     # minimum supported git version
-repodir = '.repo'               # name of repo's private directory
-S_repo = 'repo'                 # special repo repository
-S_manifests = 'manifests'       # special manifest repository
-REPO_MAIN = S_repo + '/main.py' # main script
-MIN_PYTHON_VERSION = (2, 6)     # minimum supported python version
+GIT = 'git'                      # our git command
+MIN_GIT_VERSION = (1, 7, 2)      # minimum supported git version
+repodir = '.repo'                # name of repo's private directory
+S_repo = 'repo'                  # special repo repository
+S_manifests = 'manifests'        # special manifest repository
+REPO_MAIN = S_repo + '/main.py'  # main script
+MIN_PYTHON_VERSION = (2, 6)      # minimum supported python version
+GITC_CONFIG_FILE = '/gitc/.config'
+GITC_FS_ROOT_DIR = '/gitc/manifest-rw/'
 
 
 import errno
 import optparse
-import os
 import re
 import shutil
 import stat
@@ -212,14 +216,69 @@
                  dest='config_name', action="store_true", default=False,
                  help='Always prompt for name/e-mail')
 
+
+def _GitcInitOptions(init_optparse_arg):
+  init_optparse_arg.set_usage("repo gitc-init -u url -c client [options]")
+  g = init_optparse_arg.add_option_group('GITC options')
+  g.add_option('-f', '--manifest-file',
+               dest='manifest_file',
+               help='Optional manifest file to use for this GITC client.')
+  g.add_option('-c', '--gitc-client',
+               dest='gitc_client',
+               help='The name of the gitc_client instance to create or modify.')
+
+_gitc_manifest_dir = None
+
+
+def get_gitc_manifest_dir():
+  global _gitc_manifest_dir
+  if _gitc_manifest_dir is None:
+    _gitc_manifest_dir = ''
+    try:
+      with open(GITC_CONFIG_FILE, 'r') as gitc_config:
+        for line in gitc_config:
+          match = re.match('gitc_dir=(?P<gitc_manifest_dir>.*)', line)
+          if match:
+            _gitc_manifest_dir = match.group('gitc_manifest_dir')
+    except IOError:
+      pass
+  return _gitc_manifest_dir
+
+
+def gitc_parse_clientdir(gitc_fs_path):
+  """Parse a path in the GITC FS and return its client name.
+
+  @param gitc_fs_path: A subdirectory path within the GITC_FS_ROOT_DIR.
+
+  @returns: The GITC client name
+  """
+  if gitc_fs_path == GITC_FS_ROOT_DIR:
+    return None
+  if not gitc_fs_path.startswith(GITC_FS_ROOT_DIR):
+    manifest_dir = get_gitc_manifest_dir()
+    if manifest_dir == '':
+      return None
+    if manifest_dir[-1] != '/':
+      manifest_dir += '/'
+    if gitc_fs_path == manifest_dir:
+      return None
+    if not gitc_fs_path.startswith(manifest_dir):
+      return None
+    return gitc_fs_path.split(manifest_dir)[1].split('/')[0]
+  return gitc_fs_path.split(GITC_FS_ROOT_DIR)[1].split('/')[0]
+
+
 class CloneFailure(Exception):
+
   """Indicate the remote clone of repo itself failed.
   """
 
 
-def _Init(args):
+def _Init(args, gitc_init=False):
   """Installs repo by cloning it over the network.
   """
+  if gitc_init:
+    _GitcInitOptions(init_optparse)
   opt, args = init_optparse.parse_args(args)
   if args:
     init_optparse.print_usage()
@@ -242,6 +301,26 @@
     raise CloneFailure()
 
   try:
+    if gitc_init:
+      gitc_manifest_dir = get_gitc_manifest_dir()
+      if not gitc_manifest_dir:
+        _print('fatal: GITC filesystem is not available. Exiting...',
+               file=sys.stderr)
+        sys.exit(1)
+      gitc_client = opt.gitc_client
+      if not gitc_client:
+        gitc_client = gitc_parse_clientdir(os.getcwd())
+      if not gitc_client:
+        _print('fatal: GITC client (-c) is required.', file=sys.stderr)
+        sys.exit(1)
+      client_dir = os.path.join(gitc_manifest_dir, gitc_client)
+      if not os.path.exists(client_dir):
+        os.makedirs(client_dir)
+      os.chdir(client_dir)
+      if os.path.exists(repodir):
+        # This GITC Client has already initialized repo so continue.
+        return
+
     os.mkdir(repodir)
   except OSError as e:
     if e.errno != errno.EEXIST:
@@ -358,8 +437,8 @@
   cmd = ['gpg', '--import']
   try:
     proc = subprocess.Popen(cmd,
-                            env = env,
-                            stdin = subprocess.PIPE)
+                            env=env,
+                            stdin=subprocess.PIPE)
   except OSError as e:
     if not quiet:
       _print('warning: gpg (GnuPG) is not available.', file=sys.stderr)
@@ -385,7 +464,7 @@
   """Set a git configuration option to the specified value.
   """
   cmd = [GIT, 'config', name, value]
-  if subprocess.Popen(cmd, cwd = local).wait() != 0:
+  if subprocess.Popen(cmd, cwd=local).wait() != 0:
     raise CloneFailure()
 
 
@@ -398,9 +477,9 @@
     n = netrc.netrc()
     for host in n.hosts:
       p = n.hosts[host]
-      mgr.add_password(p[1], 'http://%s/'  % host, p[0], p[2])
+      mgr.add_password(p[1], 'http://%s/' % host, p[0], p[2])
       mgr.add_password(p[1], 'https://%s/' % host, p[0], p[2])
-  except:
+  except:  # pylint: disable=bare-except
     pass
   handlers.append(urllib.request.HTTPBasicAuthHandler(mgr))
   handlers.append(urllib.request.HTTPDigestAuthHandler(mgr))
@@ -413,6 +492,7 @@
     handlers.append(urllib.request.HTTPSHandler(debuglevel=1))
   urllib.request.install_opener(urllib.request.build_opener(*handlers))
 
+
 def _Fetch(url, local, src, quiet):
   if not quiet:
     _print('Get %s' % url, file=sys.stderr)
@@ -427,22 +507,23 @@
   cmd.append('+refs/heads/*:refs/remotes/origin/*')
   cmd.append('refs/tags/*:refs/tags/*')
 
-  proc = subprocess.Popen(cmd, cwd = local, stderr = err)
+  proc = subprocess.Popen(cmd, cwd=local, stderr=err)
   if err:
     proc.stderr.read()
     proc.stderr.close()
   if proc.wait() != 0:
     raise CloneFailure()
 
+
 def _DownloadBundle(url, local, quiet):
   if not url.endswith('/'):
     url += '/'
   url += 'clone.bundle'
 
   proc = subprocess.Popen(
-    [GIT, 'config', '--get-regexp', 'url.*.insteadof'],
-    cwd = local,
-    stdout = subprocess.PIPE)
+      [GIT, 'config', '--get-regexp', 'url.*.insteadof'],
+      cwd=local,
+      stdout=subprocess.PIPE)
   for line in proc.stdout:
     m = re.compile(r'^url\.(.*)\.insteadof (.*)$').match(line)
     if m:
@@ -484,6 +565,7 @@
   finally:
     dest.close()
 
+
 def _ImportBundle(local):
   path = os.path.join(local, '.git', 'clone.bundle')
   try:
@@ -491,6 +573,7 @@
   finally:
     os.remove(path)
 
+
 def _Clone(url, local, quiet):
   """Clones a git repository to a new subdirectory of repodir
   """
@@ -503,14 +586,14 @@
 
   cmd = [GIT, 'init', '--quiet']
   try:
-    proc = subprocess.Popen(cmd, cwd = local)
+    proc = subprocess.Popen(cmd, cwd=local)
   except OSError as e:
     _print(file=sys.stderr)
     _print("fatal: '%s' is not available" % GIT, file=sys.stderr)
     _print('fatal: %s' % e, file=sys.stderr)
     _print(file=sys.stderr)
     _print('Please make sure %s is installed and in your path.' % GIT,
-          file=sys.stderr)
+           file=sys.stderr)
     raise CloneFailure()
   if proc.wait() != 0:
     _print('fatal: could not create %s' % local, file=sys.stderr)
@@ -518,12 +601,12 @@
 
   _InitHttp()
   _SetConfig(local, 'remote.origin.url', url)
-  _SetConfig(local, 'remote.origin.fetch',
-                    '+refs/heads/*:refs/remotes/origin/*')
+  _SetConfig(local,
+             'remote.origin.fetch',
+             '+refs/heads/*:refs/remotes/origin/*')
   if _DownloadBundle(url, local, quiet):
     _ImportBundle(local)
-  else:
-    _Fetch(url, local, 'origin', quiet)
+  _Fetch(url, local, 'origin', quiet)
 
 
 def _Verify(cwd, branch, quiet):
@@ -533,7 +616,7 @@
   proc = subprocess.Popen(cmd,
                           stdout=subprocess.PIPE,
                           stderr=subprocess.PIPE,
-                          cwd = cwd)
+                          cwd=cwd)
   cur = proc.stdout.read().strip()
   proc.stdout.close()
 
@@ -551,7 +634,7 @@
     if not quiet:
       _print(file=sys.stderr)
       _print("info: Ignoring branch '%s'; using tagged release '%s'"
-            % (branch, cur), file=sys.stderr)
+             % (branch, cur), file=sys.stderr)
       _print(file=sys.stderr)
 
   env = os.environ.copy()
@@ -559,10 +642,10 @@
 
   cmd = [GIT, 'tag', '-v', cur]
   proc = subprocess.Popen(cmd,
-                          stdout = subprocess.PIPE,
-                          stderr = subprocess.PIPE,
-                          cwd = cwd,
-                          env = env)
+                          stdout=subprocess.PIPE,
+                          stderr=subprocess.PIPE,
+                          cwd=cwd,
+                          env=env)
   out = proc.stdout.read()
   proc.stdout.close()
 
@@ -582,21 +665,21 @@
   """Checkout an upstream branch into the repository and track it.
   """
   cmd = [GIT, 'update-ref', 'refs/heads/default', rev]
-  if subprocess.Popen(cmd, cwd = cwd).wait() != 0:
+  if subprocess.Popen(cmd, cwd=cwd).wait() != 0:
     raise CloneFailure()
 
   _SetConfig(cwd, 'branch.default.remote', 'origin')
   _SetConfig(cwd, 'branch.default.merge', 'refs/heads/%s' % branch)
 
   cmd = [GIT, 'symbolic-ref', 'HEAD', 'refs/heads/default']
-  if subprocess.Popen(cmd, cwd = cwd).wait() != 0:
+  if subprocess.Popen(cmd, cwd=cwd).wait() != 0:
     raise CloneFailure()
 
   cmd = [GIT, 'read-tree', '--reset', '-u']
   if not quiet:
     cmd.append('-v')
   cmd.append('HEAD')
-  if subprocess.Popen(cmd, cwd = cwd).wait() != 0:
+  if subprocess.Popen(cmd, cwd=cwd).wait() != 0:
     raise CloneFailure()
 
 
@@ -608,8 +691,8 @@
 
   olddir = None
   while curdir != '/' \
-    and curdir != olddir \
-    and not repo:
+          and curdir != olddir \
+          and not repo:
     repo = os.path.join(curdir, repodir, REPO_MAIN)
     if not os.path.isfile(repo):
       repo = None
@@ -618,7 +701,7 @@
   return (repo, os.path.join(curdir, repodir))
 
 
-class _Options:
+class _Options(object):
   help = False
 
 
@@ -640,15 +723,20 @@
 
 
 def _Usage():
+  gitc_usage = ""
+  if get_gitc_manifest_dir():
+    gitc_usage = "  gitc-init Initialize a GITC Client.\n"
+
   _print(
-"""usage: repo COMMAND [ARGS]
+      """usage: repo COMMAND [ARGS]
 
 repo is not yet installed.  Use "repo init" to install it here.
 
 The most commonly used repo commands are:
 
   init      Install repo in the current working directory
-  help      Display detailed help on a command
+""" + gitc_usage +
+      """  help      Display detailed help on a command
 
 For access to the full online help, install repo ("repo init").
 """, file=sys.stderr)
@@ -660,6 +748,10 @@
     if args[0] == 'init':
       init_optparse.print_help()
       sys.exit(0)
+    elif args[0] == 'gitc-init':
+      _GitcInitOptions(init_optparse)
+      init_optparse.print_help()
+      sys.exit(0)
     else:
       _print("error: '%s' is not a bootstrap command.\n"
              '        For access to online help, install repo ("repo init").'
@@ -705,8 +797,8 @@
                            '--git-dir=%s' % gitdir,
                            'symbolic-ref',
                            'HEAD'],
-                          stdout = subprocess.PIPE,
-                          stderr = subprocess.PIPE)
+                          stdout=subprocess.PIPE,
+                          stderr=subprocess.PIPE)
   REPO_REV = proc.stdout.read().strip()
   proc.stdout.close()
 
@@ -719,12 +811,23 @@
 
 
 def main(orig_args):
-  repo_main, rel_repo_dir = _FindRepo()
   cmd, opt, args = _ParseArguments(orig_args)
 
+  repo_main, rel_repo_dir = None, None
+  # Don't use the local repo copy, make sure to switch to the gitc client first.
+  if cmd != 'gitc-init':
+    repo_main, rel_repo_dir = _FindRepo()
+
   wrapper_path = os.path.abspath(__file__)
   my_main, my_git = _RunSelf(wrapper_path)
 
+  cwd = os.getcwd()
+  if get_gitc_manifest_dir() and cwd.startswith(get_gitc_manifest_dir()):
+    _print('error: repo cannot be used in the GITC local manifest directory.'
+           '\nIf you want to work on this GITC client please rerun this '
+           'command from the corresponding client under /gitc/',
+           file=sys.stderr)
+    sys.exit(1)
   if not repo_main:
     if opt.help:
       _Usage()
@@ -732,11 +835,11 @@
       _Help(args)
     if not cmd:
       _NotInstalled()
-    if cmd == 'init':
+    if cmd == 'init' or cmd == 'gitc-init':
       if my_git:
         _SetDefaultsTo(my_git)
       try:
-        _Init(args)
+        _Init(args, gitc_init=(cmd == 'gitc-init'))
       except CloneFailure:
         shutil.rmtree(os.path.join(repodir, S_repo), ignore_errors=True)
         sys.exit(1)
diff --git a/subcmds/forall.py b/subcmds/forall.py
index 96dc99d..07ee8d5 100644
--- a/subcmds/forall.py
+++ b/subcmds/forall.py
@@ -120,6 +120,9 @@
     p.add_option('-r', '--regex',
                  dest='regex', action='store_true',
                  help="Execute the command only on projects matching regex or wildcard expression")
+    p.add_option('-i', '--inverse-regex',
+                 dest='inverse_regex', action='store_true',
+                 help="Execute the command only on projects not matching regex or wildcard expression")
     p.add_option('-g', '--groups',
                  dest='groups',
                  help="Execute the command only on projects matching the specified groups")
@@ -215,10 +218,12 @@
     if os.path.isfile(smart_sync_manifest_path):
       self.manifest.Override(smart_sync_manifest_path)
 
-    if not opt.regex:
-      projects = self.GetProjects(args, groups=opt.groups)
-    else:
+    if opt.regex:
       projects = self.FindProjects(args)
+    elif opt.inverse_regex:
+      projects = self.FindProjects(args, inverse=True)
+    else:
+      projects = self.GetProjects(args, groups=opt.groups)
 
     os.environ['REPO_COUNT'] = str(len(projects))
 
@@ -240,7 +245,8 @@
       rc = rc or errno.EINTR
     except Exception as e:
       # Catch any other exceptions raised
-      print('Got an error, terminating the pool: %r' % e,
+      print('Got an error, terminating the pool: %s: %s' %
+              (type(e).__name__, e),
             file=sys.stderr)
       pool.terminate()
       rc = rc or getattr(e, 'errno', 1)
@@ -254,7 +260,8 @@
       try:
         project = self._SerializeProject(p)
       except Exception as e:
-        print('Project list error: %r' % e,
+        print('Project list error on project %s: %s: %s' %
+                (p.name, type(e).__name__, e),
               file=sys.stderr)
         return
       except KeyboardInterrupt:
diff --git a/subcmds/gitc_delete.py b/subcmds/gitc_delete.py
new file mode 100644
index 0000000..7380c35
--- /dev/null
+++ b/subcmds/gitc_delete.py
@@ -0,0 +1,55 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+import os
+import shutil
+import sys
+
+from command import Command, GitcClientCommand
+import gitc_utils
+
+from pyversion import is_python3
+if not is_python3():
+  # pylint:disable=W0622
+  input = raw_input
+  # pylint:enable=W0622
+
+class GitcDelete(Command, GitcClientCommand):
+  common = True
+  visible_everywhere = False
+  helpSummary = "Delete a GITC Client."
+  helpUsage = """
+%prog
+"""
+  helpDescription = """
+This subcommand deletes the current GITC client, deleting the GITC manifest
+and all locally downloaded sources.
+"""
+
+  def _Options(self, p):
+    p.add_option('-f', '--force',
+                 dest='force', action='store_true',
+                 help='Force the deletion (no prompt).')
+
+  def Execute(self, opt, args):
+    if not opt.force:
+      prompt = ('This will delete GITC client: %s\nAre you sure? (yes/no) ' %
+                self.gitc_manifest.gitc_client_name)
+      response = input(prompt).lower()
+      if not response == 'yes':
+        print('Response was not "yes"\n Exiting...')
+        sys.exit(1)
+    shutil.rmtree(self.gitc_manifest.gitc_client_dir)
diff --git a/subcmds/gitc_init.py b/subcmds/gitc_init.py
new file mode 100644
index 0000000..2726eae
--- /dev/null
+++ b/subcmds/gitc_init.py
@@ -0,0 +1,82 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+import os
+import sys
+
+import gitc_utils
+from command import GitcAvailableCommand
+from manifest_xml import GitcManifest
+from subcmds import init
+import wrapper
+
+
+class GitcInit(init.Init, GitcAvailableCommand):
+  common = True
+  helpSummary = "Initialize a GITC Client."
+  helpUsage = """
+%prog [options] [client name]
+"""
+  helpDescription = """
+The '%prog' command is ran to initialize a new GITC client for use
+with the GITC file system.
+
+This command will setup the client directory, initialize repo, just
+like repo init does, and then downloads the manifest collection
+and installs it in the .repo/directory of the GITC client.
+
+Once this is done, a GITC manifest is generated by pulling the HEAD
+SHA for each project and generates the properly formatted XML file
+and installs it as .manifest in the GITC client directory.
+
+The -c argument is required to specify the GITC client name.
+
+The optional -f argument can be used to specify the manifest file to
+use for this GITC client.
+"""
+
+  def _Options(self, p):
+    super(GitcInit, self)._Options(p)
+    g = p.add_option_group('GITC options')
+    g.add_option('-f', '--manifest-file',
+                 dest='manifest_file',
+                 help='Optional manifest file to use for this GITC client.')
+    g.add_option('-c', '--gitc-client',
+                 dest='gitc_client',
+                 help='The name of the gitc_client instance to create or modify.')
+
+  def Execute(self, opt, args):
+    gitc_client = gitc_utils.parse_clientdir(os.getcwd())
+    if not gitc_client or (opt.gitc_client and gitc_client != opt.gitc_client):
+      print('fatal: Please update your repo command. See go/gitc for instructions.', file=sys.stderr)
+      sys.exit(1)
+    self.client_dir = os.path.join(gitc_utils.get_gitc_manifest_dir(),
+                                   gitc_client)
+    super(GitcInit, self).Execute(opt, args)
+
+    manifest_file = self.manifest.manifestFile
+    if opt.manifest_file:
+      if not os.path.exists(opt.manifest_file):
+        print('fatal: Specified manifest file %s does not exist.' %
+              opt.manifest_file)
+        sys.exit(1)
+      manifest_file = opt.manifest_file
+
+    manifest = GitcManifest(self.repodir, gitc_client)
+    manifest.Override(manifest_file)
+    gitc_utils.generate_gitc_manifest(None, manifest)
+    print('Please run `cd %s` to view your GITC client.' %
+          os.path.join(wrapper.Wrapper().GITC_FS_ROOT_DIR, gitc_client))
diff --git a/subcmds/help.py b/subcmds/help.py
index 4aa3f86..9bb4c8c 100644
--- a/subcmds/help.py
+++ b/subcmds/help.py
@@ -19,7 +19,8 @@
 from formatter import AbstractFormatter, DumbWriter
 
 from color import Coloring
-from command import PagedCommand, MirrorSafeCommand
+from command import PagedCommand, MirrorSafeCommand, GitcAvailableCommand, GitcClientCommand
+import gitc_utils
 
 class Help(PagedCommand, MirrorSafeCommand):
   common = False
@@ -54,9 +55,21 @@
   def _PrintCommonCommands(self):
     print('usage: repo COMMAND [ARGS]')
     print('The most commonly used repo commands are:')
+
+    def gitc_supported(cmd):
+      if not isinstance(cmd, GitcAvailableCommand) and not isinstance(cmd, GitcClientCommand):
+        return True
+      if self.manifest.isGitcClient:
+        return True
+      if isinstance(cmd, GitcClientCommand):
+        return False
+      if gitc_utils.get_gitc_manifest_dir():
+        return True
+      return False
+
     commandNames = list(sorted([name
                     for name, command in self.commands.items()
-                    if command.common]))
+                    if command.common and gitc_supported(command)]))
 
     maxlen = 0
     for name in commandNames:
diff --git a/subcmds/init.py b/subcmds/init.py
index dbb6ddd..b8e3de5 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -179,7 +179,7 @@
       r.Save()
 
     groups = re.split(r'[,\s]+', opt.groups)
-    all_platforms = ['linux', 'darwin']
+    all_platforms = ['linux', 'darwin', 'windows']
     platformize = lambda x: 'platform-' + x
     if opt.platform == 'auto':
       if (not opt.mirror and
@@ -188,7 +188,7 @@
     elif opt.platform == 'all':
       groups.extend(map(platformize, all_platforms))
     elif opt.platform in all_platforms:
-      groups.extend(platformize(opt.platform))
+      groups.append(platformize(opt.platform))
     elif opt.platform != 'none':
       print('fatal: invalid platform flag', file=sys.stderr)
       sys.exit(1)
diff --git a/subcmds/rebase.py b/subcmds/rebase.py
index 1bdc1f0..7479697 100644
--- a/subcmds/rebase.py
+++ b/subcmds/rebase.py
@@ -54,6 +54,11 @@
     p.add_option('--auto-stash',
                  dest='auto_stash', action='store_true',
                  help='Stash local modifications before starting')
+    p.add_option('-m', '--onto-manifest',
+                 dest='onto_manifest', action='store_true',
+                 help='Rebase onto the manifest version instead of upstream '
+                      'HEAD.  This helps to make sure the local tree stays '
+                      'consistent if you previously synced to a manifest.')
 
   def Execute(self, opt, args):
     all_projects = self.GetProjects(args)
@@ -106,6 +111,10 @@
       if opt.interactive:
         args.append("-i")
 
+      if opt.onto_manifest:
+        args.append('--onto')
+        args.append(project.revisionExpr)
+
       args.append(upbranch.LocalMerge)
 
       print('# %s: rebasing %s -> %s'
diff --git a/subcmds/start.py b/subcmds/start.py
index 60ad41e..d1430a9 100644
--- a/subcmds/start.py
+++ b/subcmds/start.py
@@ -14,11 +14,15 @@
 # limitations under the License.
 
 from __future__ import print_function
+import os
 import sys
+
 from command import Command
 from git_config import IsId
 from git_command import git
+import gitc_utils
 from progress import Progress
+from project import SyncBuffer
 
 class Start(Command):
   common = True
@@ -53,20 +57,57 @@
         print("error: at least one project must be specified", file=sys.stderr)
         sys.exit(1)
 
-    all_projects = self.GetProjects(projects)
+    all_projects = self.GetProjects(projects,
+                                    missing_ok=bool(self.gitc_manifest))
+
+    # This must happen after we find all_projects, since GetProjects may need
+    # the local directory, which will disappear once we save the GITC manifest.
+    if self.gitc_manifest:
+      gitc_projects = self.GetProjects(projects, manifest=self.gitc_manifest,
+                                       missing_ok=True)
+      for project in gitc_projects:
+        if project.old_revision:
+          project.already_synced = True
+        else:
+          project.already_synced = False
+          project.old_revision = project.revisionExpr
+        project.revisionExpr = None
+      # Save the GITC manifest.
+      gitc_utils.save_manifest(self.gitc_manifest)
+
+      # Make sure we have a valid CWD
+      if not os.path.exists(os.getcwd()):
+        os.chdir(self.manifest.topdir)
 
     pm = Progress('Starting %s' % nb, len(all_projects))
     for project in all_projects:
       pm.update()
+
+      if self.gitc_manifest:
+        gitc_project = self.gitc_manifest.paths[project.relpath]
+        # Sync projects that have not been opened.
+        if not gitc_project.already_synced:
+          proj_localdir = os.path.join(self.gitc_manifest.gitc_client_dir,
+                                       project.relpath)
+          project.worktree = proj_localdir
+          if not os.path.exists(proj_localdir):
+            os.makedirs(proj_localdir)
+          project.Sync_NetworkHalf()
+          sync_buf = SyncBuffer(self.manifest.manifestProject.config)
+          project.Sync_LocalHalf(sync_buf)
+          project.revisionId = gitc_project.old_revision
+
       # If the current revision is a specific SHA1 then we can't push back
       # to it; so substitute with dest_branch if defined, or with manifest
       # default revision instead.
+      branch_merge = ''
       if IsId(project.revisionExpr):
         if project.dest_branch:
-          project.revisionExpr = project.dest_branch
+          branch_merge = project.dest_branch
         else:
-          project.revisionExpr = self.manifest.default.revisionExpr
-      if not project.StartBranch(nb):
+          branch_merge = self.manifest.default.revisionExpr
+
+      if not project.StartBranch(nb, branch_merge=branch_merge):
         err.append(project)
     pm.end()
 
diff --git a/subcmds/sync.py b/subcmds/sync.py
index 43d450b..4af411c 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -23,18 +23,26 @@
 import socket
 import subprocess
 import sys
+import tempfile
 import time
 
 from pyversion import is_python3
 if is_python3():
+  import http.cookiejar as cookielib
+  import urllib.error
   import urllib.parse
+  import urllib.request
   import xmlrpc.client
 else:
+  import cookielib
   import imp
+  import urllib2
   import urlparse
   import xmlrpclib
   urllib = imp.new_module('urllib')
+  urllib.error = urllib2
   urllib.parse = urlparse
+  urllib.request = urllib2
   xmlrpc = imp.new_module('xmlrpc')
   xmlrpc.client = xmlrpclib
 
@@ -57,7 +65,9 @@
   multiprocessing = None
 
 from git_command import GIT, git_require
+from git_config import GetUrlCookieFile
 from git_refs import R_HEADS, HEAD
+import gitc_utils
 from project import Project
 from project import RemoteSpec
 from command import Command, MirrorSafeCommand
@@ -65,6 +75,7 @@
 from project import SyncBuffer
 from progress import Progress
 from wrapper import Wrapper
+from manifest_xml import GitcManifest
 
 _ONE_DAY_S = 24 * 60 * 60
 
@@ -140,6 +151,9 @@
 are fixed to a sha1 revision if the sha1 revision does not already
 exist locally.
 
+The --prune option can be used to remove any refs that no longer
+exist on the remote.
+
 SSH Connections
 ---------------
 
@@ -223,6 +237,8 @@
     p.add_option('--optimized-fetch',
                  dest='optimized_fetch', action='store_true',
                  help='only fetch projects fixed to sha1 if revision does not exist locally')
+    p.add_option('--prune', dest='prune', action='store_true',
+                 help='delete refs that no longer exist on the remote')
     if show_smart:
       p.add_option('-s', '--smart-sync',
                    dest='smart_sync', action='store_true',
@@ -294,7 +310,8 @@
           force_sync=opt.force_sync,
           clone_bundle=not opt.no_clone_bundle,
           no_tags=opt.no_tags, archive=self.manifest.IsArchive,
-          optimized_fetch=opt.optimized_fetch)
+          optimized_fetch=opt.optimized_fetch,
+          prune=opt.prune)
         self._fetch_times.Set(project, time.time() - start)
 
         # Lock around all the rest of the code, since printing, updating a set
@@ -303,6 +320,7 @@
         did_lock = True
 
         if not success:
+          err_event.set()
           print('error: Cannot fetch %s' % project.name, file=sys.stderr)
           if opt.force_broken:
             print('warn: --force-broken, continuing to sync',
@@ -313,7 +331,7 @@
         fetched.add(project.gitdir)
         pm.update()
       except _FetchError:
-        err_event.set()
+        pass
       except Exception as e:
         print('error: Cannot fetch %s (%s: %s)' \
             % (project.name, type(e).__name__, str(e)), file=sys.stderr)
@@ -554,19 +572,18 @@
           try:
             info = netrc.netrc()
           except IOError:
-            print('.netrc file does not exist or could not be opened',
-                  file=sys.stderr)
+            # .netrc file does not exist or could not be opened
+            pass
           else:
             try:
               parse_result = urllib.parse.urlparse(manifest_server)
               if parse_result.hostname:
-                username, _account, password = \
-                  info.authenticators(parse_result.hostname)
-            except TypeError:
-              # TypeError is raised when the given hostname is not present
-              # in the .netrc file.
-              print('No credentials found for %s in .netrc'
-                    % parse_result.hostname, file=sys.stderr)
+                auth = info.authenticators(parse_result.hostname)
+                if auth:
+                  username, _account, password = auth
+                else:
+                  print('No credentials found for %s in .netrc'
+                        % parse_result.hostname, file=sys.stderr)
             except netrc.NetrcParseError as e:
               print('Error parsing .netrc file: %s' % e, file=sys.stderr)
 
@@ -575,8 +592,12 @@
                                                     (username, password),
                                                     1)
 
+      transport = PersistentTransport(manifest_server)
+      if manifest_server.startswith('persistent-'):
+        manifest_server = manifest_server[len('persistent-'):]
+
       try:
-        server = xmlrpc.client.Server(manifest_server)
+        server = xmlrpc.client.Server(manifest_server, transport=transport)
         if opt.smart_sync:
           p = self.manifest.manifestProject
           b = p.GetBranch(p.CurrentBranch)
@@ -656,6 +677,42 @@
       self._ReloadManifest(manifest_name)
       if opt.jobs is None:
         self.jobs = self.manifest.default.sync_j
+
+    if self.gitc_manifest:
+      gitc_manifest_projects = self.GetProjects(args,
+                                                missing_ok=True)
+      gitc_projects = []
+      opened_projects = []
+      for project in gitc_manifest_projects:
+        if project.relpath in self.gitc_manifest.paths and \
+           self.gitc_manifest.paths[project.relpath].old_revision:
+          opened_projects.append(project.relpath)
+        else:
+          gitc_projects.append(project.relpath)
+
+      if not args:
+        gitc_projects = None
+
+      if gitc_projects != [] and not opt.local_only:
+        print('Updating GITC client: %s' % self.gitc_manifest.gitc_client_name)
+        manifest = GitcManifest(self.repodir, self.gitc_manifest.gitc_client_name)
+        if manifest_name:
+          manifest.Override(manifest_name)
+        else:
+          manifest.Override(self.manifest.manifestFile)
+        gitc_utils.generate_gitc_manifest(self.gitc_manifest,
+                                          manifest,
+                                          gitc_projects)
+        print('GITC client successfully synced.')
+
+      # The opened projects need to be synced as normal, therefore we
+      # generate a new args list to represent the opened projects.
+      # TODO: make this more reliable -- if there's a project name/path overlap,
+      # this may choose the wrong project.
+      args = [os.path.relpath(self.manifest.paths[p].worktree, os.getcwd())
+              for p in opened_projects]
+      if not args:
+        return
     all_projects = self.GetProjects(args,
                                     missing_ok=True,
                                     submodules_ok=opt.fetch_submodules)
@@ -850,3 +907,100 @@
         os.remove(self._path)
       except OSError:
         pass
+
+# This is a replacement for xmlrpc.client.Transport using urllib2
+# and supporting persistent-http[s]. It cannot change hosts from
+# request to request like the normal transport, the real url
+# is passed during initialization.
+class PersistentTransport(xmlrpc.client.Transport):
+  def __init__(self, orig_host):
+    self.orig_host = orig_host
+
+  def request(self, host, handler, request_body, verbose=False):
+    with GetUrlCookieFile(self.orig_host, not verbose) as (cookiefile, proxy):
+      # Python doesn't understand cookies with the #HttpOnly_ prefix
+      # Since we're only using them for HTTP, copy the file temporarily,
+      # stripping those prefixes away.
+      if cookiefile:
+        tmpcookiefile = tempfile.NamedTemporaryFile()
+        tmpcookiefile.write("# HTTP Cookie File")
+        try:
+          with open(cookiefile) as f:
+            for line in f:
+              if line.startswith("#HttpOnly_"):
+                line = line[len("#HttpOnly_"):]
+              tmpcookiefile.write(line)
+          tmpcookiefile.flush()
+
+          cookiejar = cookielib.MozillaCookieJar(tmpcookiefile.name)
+          try:
+            cookiejar.load()
+          except cookielib.LoadError:
+            cookiejar = cookielib.CookieJar()
+        finally:
+          tmpcookiefile.close()
+      else:
+        cookiejar = cookielib.CookieJar()
+
+      proxyhandler = urllib.request.ProxyHandler
+      if proxy:
+        proxyhandler = urllib.request.ProxyHandler({
+            "http": proxy,
+            "https": proxy })
+
+      opener = urllib.request.build_opener(
+          urllib.request.HTTPCookieProcessor(cookiejar),
+          proxyhandler)
+
+      url = urllib.parse.urljoin(self.orig_host, handler)
+      parse_results = urllib.parse.urlparse(url)
+
+      scheme = parse_results.scheme
+      if scheme == 'persistent-http':
+        scheme = 'http'
+      if scheme == 'persistent-https':
+        # If we're proxying through persistent-https, use http. The
+        # proxy itself will do the https.
+        if proxy:
+          scheme = 'http'
+        else:
+          scheme = 'https'
+
+      # Parse out any authentication information using the base class
+      host, extra_headers, _ = self.get_host_info(parse_results.netloc)
+
+      url = urllib.parse.urlunparse((
+          scheme,
+          host,
+          parse_results.path,
+          parse_results.params,
+          parse_results.query,
+          parse_results.fragment))
+
+      request = urllib.request.Request(url, request_body)
+      if extra_headers is not None:
+        for (name, header) in extra_headers:
+          request.add_header(name, header)
+      request.add_header('Content-Type', 'text/xml')
+      try:
+        response = opener.open(request)
+      except urllib.error.HTTPError as e:
+        if e.code == 501:
+          # We may have been redirected through a login process
+          # but our POST turned into a GET. Retry.
+          response = opener.open(request)
+        else:
+          raise
+
+      p, u = xmlrpc.client.getparser()
+      while 1:
+        data = response.read(1024)
+        if not data:
+          break
+        p.feed(data)
+      p.close()
+      return u.close()
+
+  def close(self):
+    pass
+
diff --git a/tests/fixtures/gitc_config b/tests/fixtures/gitc_config
new file mode 100644
index 0000000..a7f3d1c
--- /dev/null
+++ b/tests/fixtures/gitc_config
@@ -0,0 +1 @@
+gitc_dir=/test/usr/local/google/gitc
diff --git a/tests/test_wrapper.py b/tests/test_wrapper.py
new file mode 100644
index 0000000..fb32e38
--- /dev/null
+++ b/tests/test_wrapper.py
@@ -0,0 +1,75 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import unittest
+
+import wrapper
+
+def fixture(*paths):
+  """Return a path relative to tests/fixtures.
+  """
+  return os.path.join(os.path.dirname(__file__), 'fixtures', *paths)
+
+class RepoWrapperUnitTest(unittest.TestCase):
+  """Tests helper functions in the repo wrapper
+  """
+  def setUp(self):
+    """Load the wrapper module every time
+    """
+    wrapper._wrapper_module = None
+    self.wrapper = wrapper.Wrapper()
+
+  def test_get_gitc_manifest_dir_no_gitc(self):
+    """
+    Test reading a missing gitc config file
+    """
+    self.wrapper.GITC_CONFIG_FILE = fixture('missing_gitc_config')
+    val = self.wrapper.get_gitc_manifest_dir()
+    self.assertEqual(val, '')
+
+  def test_get_gitc_manifest_dir(self):
+    """
+    Test reading the gitc config file and parsing the directory
+    """
+    self.wrapper.GITC_CONFIG_FILE = fixture('gitc_config')
+    val = self.wrapper.get_gitc_manifest_dir()
+    self.assertEqual(val, '/test/usr/local/google/gitc')
+
+  def test_gitc_parse_clientdir_no_gitc(self):
+    """
+    Test parsing the gitc clientdir without gitc running
+    """
+    self.wrapper.GITC_CONFIG_FILE = fixture('missing_gitc_config')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/something'), None)
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/gitc/manifest-rw/test'), 'test')
+
+  def test_gitc_parse_clientdir(self):
+    """
+    Test parsing the gitc clientdir
+    """
+    self.wrapper.GITC_CONFIG_FILE = fixture('gitc_config')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/something'), None)
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/gitc/manifest-rw/test'), 'test')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/gitc/manifest-rw/test/'), 'test')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/gitc/manifest-rw/test/extra'), 'test')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/test/usr/local/google/gitc/test'), 'test')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/test/usr/local/google/gitc/test/'), 'test')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/test/usr/local/google/gitc/test/extra'), 'test')
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/gitc/manifest-rw/'), None)
+    self.assertEqual(self.wrapper.gitc_parse_clientdir('/test/usr/local/google/gitc/'), None)
+
+if __name__ == '__main__':
+  unittest.main()