depot_tools: Restore third_party/upload.py

This is a partial revert of
https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1702495

It is used by my_activity.py (via rietveld)

Bug: 984745, 984182
Change-Id: Ic9a3e59a2ffb4b500666f9ad2ee076c8bb81a3d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1703390
Reviewed-by: Andy Perelson <ajp@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

third_party/upload.py

@@ -0,0 +1,2565 @@
+#!/usr/bin/env python
+# coding: utf-8
+#
+# Copyright 2007 Google Inc.
+#
+# 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.
+
+"""Tool for uploading diffs from a version control system to the codereview app.
+
+Usage summary: upload.py [options] [-- diff_options] [path...]
+
+Diff options are passed to the diff command of the underlying system.
+
+Supported version control systems:
+  Git
+  Mercurial
+  Subversion
+  Perforce
+  CVS
+
+It is important for Git/Mercurial users to specify a tree/node/branch to diff
+against by using the '--rev' option.
+"""
+# This code is derived from appcfg.py in the App Engine SDK (open source),
+# and from ASPN recipe #146306.
+
+from __future__ import print_function
+
+import cookielib
+import errno
+import fnmatch
+import getpass
+import logging
+import marshal
+import mimetypes
+import optparse
+import os
+import re
+import socket
+import subprocess
+import sys
+import urllib
+import urllib2
+import urlparse
+
+from multiprocessing.pool import ThreadPool
+
+import appengine_mapper
+
+# The configparser module was renamed in Python 3.
+try:
+  import configparser
+except ImportError:
+  import ConfigParser as configparser
+
+# The md5 module was deprecated in Python 2.5.
+try:
+  from hashlib import md5
+except ImportError:
+  from md5 import md5
+
+try:
+  import readline
+except ImportError:
+  pass
+
+try:
+  import keyring
+except:
+  keyring = None
+
+# auth.py is a part of depot_tools.
+# TODO(vadimsh): Merge upload.py into depot_tools
+import auth
+
+# The logging verbosity:
+#  0: Errors only.
+#  1: Status messages.
+#  2: Info logs.
+#  3: Debug logs.
+verbosity = 1
+LOGGER = logging.getLogger('upload')
+
+# The account type used for authentication.
+# This line could be changed by the review server (see handler for
+# upload.py).
+AUTH_ACCOUNT_TYPE = "GOOGLE"
+
+# URL of the default review server. As for AUTH_ACCOUNT_TYPE, this line could be
+# changed by the review server (see handler for upload.py).
+DEFAULT_REVIEW_SERVER = "codereview.appspot.com"
+
+# Max size of patch or base file.
+MAX_UPLOAD_SIZE = 900 * 1024
+
+
+# Constants for version control names.  Used by GuessVCSName.
+VCS_GIT = "Git"
+VCS_MERCURIAL = "Mercurial"
+VCS_SUBVERSION = "Subversion"
+VCS_PERFORCE = "Perforce"
+VCS_CVS = "CVS"
+VCS_UNKNOWN = "Unknown"
+
+VCS = [
+  {'name': VCS_MERCURIAL,
+   'aliases': ['hg', 'mercurial']},
+  {'name': VCS_SUBVERSION,
+   'aliases': ['svn', 'subversion'],},
+  {'name': VCS_PERFORCE,
+   'aliases': ['p4', 'perforce']},
+  {'name': VCS_GIT,
+   'aliases': ['git']},
+  {'name': VCS_CVS,
+   'aliases': ['cvs']},
+  ]
+
+
+VCS_SHORT_NAMES = []    # hg, svn, ...
+VCS_ABBREVIATIONS = {}  # alias: name, ...
+for vcs in VCS:
+  VCS_SHORT_NAMES.append(min(vcs['aliases'], key=len))
+  VCS_ABBREVIATIONS.update((alias, vcs['name']) for alias in vcs['aliases'])
+
+UPLOAD_TIMEOUT = 120
+MAX_UPLOAD_ATTEMPTS = 3
+
+
+# The result of parsing Subversion's [auto-props] setting.
+svn_auto_props_map = None
+
+def GetEmail(prompt):
+  """Prompts the user for their email address and returns it.
+
+  The last used email address is saved to a file and offered up as a suggestion
+  to the user. If the user presses enter without typing in anything the last
+  used email address is used. If the user enters a new address, it is saved
+  for next time we prompt.
+
+  """
+  last_email_file_name = os.path.expanduser("~/.last_codereview_email_address")
+  last_email = ""
+  if os.path.exists(last_email_file_name):
+    try:
+      last_email_file = open(last_email_file_name, "r")
+      last_email = last_email_file.readline().strip("\n")
+      last_email_file.close()
+      prompt += " [%s]" % last_email
+    except IOError as e:
+      pass
+  email = raw_input(prompt + ": ").strip()
+  if email:
+    try:
+      last_email_file = open(last_email_file_name, "w")
+      last_email_file.write(email)
+      last_email_file.close()
+    except IOError as e:
+      pass
+  else:
+    email = last_email
+  return email
+
+
+def StatusUpdate(msg):
+  """Print a status message to stdout.
+
+  If 'verbosity' is greater than 0, print the message.
+
+  Args:
+    msg: The string to print.
+  """
+  if verbosity > 0:
+    print(msg)
+
+
+def ErrorExit(msg):
+  """Print an error message to stderr and exit."""
+  print(msg, file=sys.stderr)
+  sys.exit(1)
+
+
+class ClientLoginError(urllib2.HTTPError):
+  """Raised to indicate there was an error authenticating with ClientLogin."""
+
+  def __init__(self, url, code, msg, headers, args):
+    urllib2.HTTPError.__init__(self, url, code, msg, headers, None)
+    self.args = args
+    self._reason = args["Error"]
+    self.info = args.get("Info", None)
+
+  @property
+  def reason(self):
+    # reason is a property on python 2.7 but a member variable on <=2.6.
+    # self.args is modified so it cannot be used as-is so save the value in
+    # self._reason.
+    return self._reason
+
+
+class AbstractRpcServer(object):
+  """Provides a common interface for a simple RPC server."""
+
+  def __init__(self, host, auth_function, host_override=None,
+               request_path_prefix=None, extra_headers=None,
+               save_cookies=False, account_type=AUTH_ACCOUNT_TYPE):
+    """Creates a new AbstractRpcServer.
+
+    Args:
+      host: The host to send requests to.
+      auth_function: A function that takes no arguments and returns an
+        (email, password) tuple when called. Will be called if authentication
+        is required.
+      host_override: The host header to send to the server (defaults to host).
+      request_path_prefix: A string to prefix all URL paths with (e.g. 'bots/').
+      extra_headers: A dict of extra headers to append to every request.
+      save_cookies: If True, save the authentication cookies to local disk.
+        If False, use an in-memory cookiejar instead.  Subclasses must
+        implement this functionality.  Defaults to False.
+      account_type: Account type used for authentication. Defaults to
+        AUTH_ACCOUNT_TYPE.
+    """
+    self.host = host
+    if (not self.host.startswith("http://") and
+        not self.host.startswith("https://")):
+      self.host = "http://" + self.host
+    self.host_override = host_override
+    self.request_path_prefix = request_path_prefix or ''
+    self.auth_function = auth_function
+    self.authenticated = False
+    self.extra_headers = extra_headers or {}
+    self.save_cookies = save_cookies
+    self.account_type = account_type
+    self.opener = self._GetOpener()
+    if self.host_override:
+      LOGGER.info("Server: %s; Host: %s", self.host, self.host_override)
+    else:
+      LOGGER.info("Server: %s", self.host)
+
+  def _GetOpener(self):
+    """Returns an OpenerDirector for making HTTP requests.
+
+    Returns:
+      A urllib2.OpenerDirector object.
+    """
+    raise NotImplementedError()
+
+  def _CreateRequest(self, url, data=None):
+    """Creates a new urllib request."""
+    LOGGER.debug("Creating request for: '%s' with payload:\n%s", url, data)
+    req = urllib2.Request(url, data=data, headers={"Accept": "text/plain"})
+    if self.host_override:
+      req.add_header("Host", self.host_override)
+    for key, value in self.extra_headers.iteritems():
+      req.add_header(key, value)
+    return req
+
+  def _GetAuthToken(self, email, password, internal=False):
+    """Uses ClientLogin to authenticate the user, returning an auth token.
+
+    Args:
+      email:    The user's email address
+      password: The user's password
+
+    Raises:
+      ClientLoginError: If there was an error authenticating with ClientLogin.
+      HTTPError: If there was some other form of HTTP error.
+
+    Returns:
+      The authentication token returned by ClientLogin.
+    """
+    account_type = self.account_type
+    if self.host.endswith(".google.com"):
+      # Needed for use inside Google.
+      account_type = "HOSTED"
+    service = ('ClientLogin') if not internal else ('ClientAuth')
+    req = self._CreateRequest(
+        url="https://www.google.com/accounts/%s" % (service,),
+        data=urllib.urlencode({
+            "Email": email,
+            "Passwd": password,
+            "service": "ah",
+            "source": "rietveld-codereview-upload",
+            "accountType": account_type,
+        }),
+    )
+    try:
+      response = self.opener.open(req)
+      response_body = response.read()
+      response_dict = dict(x.split("=")
+                           for x in response_body.split("\n") if x)
+      return response_dict["Auth"]
+    except urllib2.HTTPError as e:
+      if e.code == 403:
+        body = e.read()
+        response_dict = dict(x.split("=", 1) for x in body.split("\n") if x)
+        raise ClientLoginError(req.get_full_url(), e.code, e.msg,
+                               e.headers, response_dict)
+      else:
+        raise
+
+  def _GetAuthCookie(self, auth_token):
+    """Fetches authentication cookies for an authentication token.
+
+    Args:
+      auth_token: The authentication token returned by ClientLogin.
+
+    Raises:
+      HTTPError: If there was an error fetching the authentication cookies.
+    """
+    # This is a dummy value to allow us to identify when we're successful.
+    continue_location = "http://localhost/"
+    args = {"continue": continue_location, "auth": auth_token}
+    req = self._CreateRequest("%s/_ah/login?%s" %
+                              (self.host, urllib.urlencode(args)))
+    try:
+      response = self.opener.open(req)
+    except urllib2.HTTPError as e:
+      response = e
+    if (response.code != 302 or
+        response.info()["location"] != continue_location):
+      raise urllib2.HTTPError(req.get_full_url(), response.code, response.msg,
+                              response.headers, response.fp)
+    self.authenticated = True
+
+  def _Authenticate(self, force_refresh):
+    """Authenticates the user.
+
+    The authentication process works as follows:
+     1) We get a username and password from the user
+     2) We use ClientLogin to obtain an AUTH token for the user
+        (see http://code.google.com/apis/accounts/AuthForInstalledApps.html).
+     3) We pass the auth token to /_ah/login on the server to obtain an
+        authentication cookie. If login was successful, it tries to redirect
+        us to the URL we provided.
+
+    If we attempt to access the upload API without first obtaining an
+    authentication cookie, it returns a 401 response (or a 302) and
+    directs us to authenticate ourselves with ClientLogin.
+    """
+    for i in range(3):
+      credentials = self.auth_function()
+
+      # Try external, then internal.
+      e = None
+      error_map = None
+      try:
+        auth_token = self._GetAuthToken(credentials[0], credentials[1])
+      except urllib2.HTTPError:
+        try:
+          # Try internal endpoint.
+          error_map = {
+              "badauth": "BadAuthentication",
+              "cr": "CaptchaRequired",
+              "adel": "AccountDeleted",
+              "adis": "AccountDisabled",
+              "sdis": "ServiceDisabled",
+              "ire": "ServiceUnavailable",
+          }
+          auth_token = self._GetAuthToken(credentials[0], credentials[1],
+                                          internal=True)
+        except ClientLoginError as exc:
+          e = exc
+      if e:
+        print('', file=sys.stderr)
+        error_message = e.reason
+        if error_map:
+          error_message = error_map.get(error_message, error_message)
+        if error_message == "BadAuthentication":
+          if e.info == "InvalidSecondFactor":
+            print >> sys.stderr, (
+                "Use an application-specific password instead "
+                "of your regular account password.\n"
+                "See http://www.google.com/"
+                "support/accounts/bin/answer.py?answer=185833")
+          else:
+            print("Invalid username or password.", file=sys.stderr)
+        elif error_message == "CaptchaRequired":
+          print >> sys.stderr, (
+              "Please go to\n"
+              "https://www.google.com/accounts/DisplayUnlockCaptcha\n"
+              "and verify you are a human.  Then try again.\n"
+              "If you are using a Google Apps account the URL is:\n"
+              "https://www.google.com/a/yourdomain.com/UnlockCaptcha")
+        elif error_message == "NotVerified":
+          print("Account not verified.", file=sys.stderr)
+        elif error_message == "TermsNotAgreed":
+          print("User has not agreed to TOS.", file=sys.stderr)
+        elif error_message == "AccountDeleted":
+          print("The user account has been deleted.", file=sys.stderr)
+        elif error_message == "AccountDisabled":
+          print("The user account has been disabled.", file=sys.stderr)
+          break
+        elif error_message == "ServiceDisabled":
+          print("The user's access to the service has been disabled.",
+                file=sys.stderr)
+        elif error_message == "ServiceUnavailable":
+          print("The service is not available; try again later.",
+                file=sys.stderr)
+        else:
+          # Unknown error.
+          raise e
+        print('', file=sys.stderr)
+        continue
+      self._GetAuthCookie(auth_token)
+      return
+
+  def Send(self, request_path, payload=None,
+           content_type="application/octet-stream",
+           timeout=None,
+           extra_headers=None,
+           **kwargs):
+    """Sends an RPC and returns the response.
+
+    Args:
+      request_path: The path to send the request to, eg /api/appversion/create.
+      payload: The body of the request, or None to send an empty request.
+      content_type: The Content-Type header to use.
+      timeout: timeout in seconds; default None i.e. no timeout.
+        (Note: for large requests on OS X, the timeout doesn't work right.)
+      extra_headers: Dict containing additional HTTP headers that should be
+        included in the request (string header names mapped to their values),
+        or None to not include any additional headers.
+      kwargs: Any keyword arguments are converted into query string parameters.
+
+    Returns:
+      The response body, as a string.
+    """
+    # TODO: Don't require authentication.  Let the server say
+    # whether it is necessary.
+    if not self.authenticated and self.auth_function:
+      self._Authenticate(force_refresh=False)
+
+    old_timeout = socket.getdefaulttimeout()
+    socket.setdefaulttimeout(timeout)
+    auth_attempted = False
+    try:
+      tries = 0
+      while True:
+        tries += 1
+        args = dict(kwargs)
+        url = "%s%s%s" % (self.host, self.request_path_prefix, request_path)
+        url = appengine_mapper.MapUrl(url)
+        if args:
+          url += "?" + urllib.urlencode(args)
+        req = self._CreateRequest(url=url, data=payload)
+        req.add_header("Content-Type", content_type)
+        if extra_headers:
+          for header, value in extra_headers.items():
+            req.add_header(header, value)
+        try:
+          f = self.opener.open(req, timeout=70)
+          response = f.read()
+          f.close()
+          return response
+        except urllib2.HTTPError as e:
+          if tries > 3:
+            raise
+          elif e.code in (302, 401, 403):
+            if not self.auth_function:
+              raise
+            # Already tried force refresh, didn't help -> give up with error.
+            if auth_attempted:
+              raise auth.AuthenticationError(
+                  'Access to %s is denied (server returned HTTP %d).'
+                  % (self.host, e.code))
+            self._Authenticate(force_refresh=True)
+            auth_attempted = True
+          elif e.code == 301:
+            # Handle permanent redirect manually.
+            url = e.info()["location"]
+            url_loc = urlparse.urlparse(url)
+            self.host = '%s://%s' % (url_loc[0], url_loc[1])
+          elif e.code >= 500:
+            # TODO: We should error out on a 500, but the server is too flaky
+            # for that at the moment.
+            StatusUpdate('Upload got a 500 response: %d' % e.code)
+          else:
+            raise
+    finally:
+      socket.setdefaulttimeout(old_timeout)
+
+
+class HttpRpcServer(AbstractRpcServer):
+  """Provides a simplified RPC-style interface for HTTP requests."""
+
+  def _Authenticate(self, force_refresh):
+    """Save the cookie jar after authentication."""
+    if isinstance(self.auth_function, auth.Authenticator):
+      try:
+        access_token = self.auth_function.get_access_token(force_refresh)
+      except auth.LoginRequiredError:
+        # Attempt to make unauthenticated request first if there's no cached
+        # credentials. HttpRpcServer calls __Authenticate(force_refresh=True)
+        # again if unauthenticated request doesn't work.
+        if not force_refresh:
+          return
+        raise
+      self.extra_headers['Authorization'] = 'Bearer %s' % (
+          access_token.token,)
+    else:
+      super(HttpRpcServer, self)._Authenticate(force_refresh)
+      if self.save_cookies:
+        StatusUpdate("Saving authentication cookies to %s" % self.cookie_file)
+        self.cookie_jar.save()
+
+  def _GetOpener(self):
+    """Returns an OpenerDirector that supports cookies and ignores redirects.
+
+    Returns:
+      A urllib2.OpenerDirector object.
+    """
+    opener = urllib2.OpenerDirector()
+    opener.add_handler(urllib2.ProxyHandler())
+    opener.add_handler(urllib2.UnknownHandler())
+    opener.add_handler(urllib2.HTTPHandler())
+    opener.add_handler(urllib2.HTTPDefaultErrorHandler())
+    opener.add_handler(urllib2.HTTPSHandler())
+    opener.add_handler(urllib2.HTTPErrorProcessor())
+    if self.save_cookies:
+      self.cookie_file = os.path.expanduser("~/.codereview_upload_cookies")
+      self.cookie_jar = cookielib.MozillaCookieJar(self.cookie_file)
+      if os.path.exists(self.cookie_file):
+        try:
+          self.cookie_jar.load()
+          self.authenticated = True
+          StatusUpdate("Loaded authentication cookies from %s" %
+                       self.cookie_file)
+        except (cookielib.LoadError, IOError):
+          # Failed to load cookies - just ignore them.
+          pass
+      else:
+        # Create an empty cookie file with mode 600
+        fd = os.open(self.cookie_file, os.O_CREAT, 0o600)
+        os.close(fd)
+      # Always chmod the cookie file
+      os.chmod(self.cookie_file, 0o600)
+    else:
+      # Don't save cookies across runs of update.py.
+      self.cookie_jar = cookielib.CookieJar()
+    opener.add_handler(urllib2.HTTPCookieProcessor(self.cookie_jar))
+    return opener
+
+
+class CondensedHelpFormatter(optparse.IndentedHelpFormatter):
+  """Frees more horizontal space by removing indentation from group
+     options and collapsing arguments between short and long, e.g.
+     '-o ARG, --opt=ARG' to -o --opt ARG"""
+
+  def format_heading(self, heading):
+    return "%s:\n" % heading
+
+  def format_option(self, option):
+    self.dedent()
+    res = optparse.HelpFormatter.format_option(self, option)
+    self.indent()
+    return res
+
+  def format_option_strings(self, option):
+    self.set_long_opt_delimiter(" ")
+    optstr = optparse.HelpFormatter.format_option_strings(self, option)
+    optlist = optstr.split(", ")
+    if len(optlist) > 1:
+      if option.takes_value():
+        # strip METAVAR from all but the last option
+        optlist = [x.split()[0] for x in optlist[:-1]] + optlist[-1:]
+      optstr = " ".join(optlist)
+    return optstr
+
+
+parser = optparse.OptionParser(
+  usage=("%prog [options] [-- diff_options] [path...]\n"
+         "See also: http://code.google.com/p/rietveld/wiki/UploadPyUsage"),
+  add_help_option=False,
+  formatter=CondensedHelpFormatter()
+  )
+parser.add_option("-h", "--help", action="store_true",
+                  help="Show this help message and exit.")
+parser.add_option("-y", "--assume_yes", action="store_true",
+                  dest="assume_yes", default=False,
+                  help="Assume that the answer to yes/no questions is 'yes'.")
+# Logging
+group = parser.add_option_group("Logging options")
+group.add_option("-q", "--quiet", action="store_const", const=0,
+                 dest="verbose", help="Print errors only.")
+group.add_option("-v", "--verbose", action="store_const", const=2,
+                 dest="verbose", default=1,
+                 help="Print info level logs.")
+group.add_option("--noisy", action="store_const", const=3,
+                 dest="verbose", help="Print all logs.")
+group.add_option("--print_diffs", dest="print_diffs", action="store_true",
+                 help="Print full diffs.")
+# Review server
+group = parser.add_option_group("Review server options")
+group.add_option("-s", "--server", action="store", dest="server",
+                 default=DEFAULT_REVIEW_SERVER,
+                 metavar="SERVER",
+                 help=("The server to upload to. The format is host[:port]. "
+                       "Defaults to '%default'."))
+group.add_option("-e", "--email", action="store", dest="email",
+                 metavar="EMAIL", default=None,
+                 help="The username to use. Will prompt if omitted.")
+group.add_option("-j", "--number-parallel-uploads",
+                 dest="num_upload_threads", default=8,
+                 help="Number of uploads to do in parallel.")
+# Authentication
+auth.add_auth_options(parser)
+# Issue
+group = parser.add_option_group("Issue options")
+group.add_option("-t", "--title", action="store", dest="title",
+                 help="New issue subject or new patch set title")
+group.add_option("--project", action="store", dest="project",
+                 help="The project the issue belongs to")
+group.add_option("-m", "--message", action="store", dest="message",
+                 default=None,
+                 help="New issue description or new patch set message")
+group.add_option("-F", "--file", action="store", dest="file",
+                 default=None, help="Read the message above from file.")
+group.add_option("-r", "--reviewers", action="store", dest="reviewers",
+                 metavar="REVIEWERS", default=None,
+                 help="Add reviewers (comma separated email addresses).")
+group.add_option("--cc", action="store", dest="cc",
+                 metavar="CC", default=None,
+                 help="Add CC (comma separated email addresses).")
+group.add_option("--private", action="store_true", dest="private",
+                 default=False,
+                 help="Make the issue restricted to reviewers and those CCed")
+# Upload options
+group = parser.add_option_group("Patch options")
+group.add_option("-i", "--issue", type="int", action="store",
+                 metavar="ISSUE", default=None,
+                 help="Issue number to which to add. Defaults to new issue.")
+group.add_option("--target_ref", action="store", dest="target_ref",
+                 default=None,
+                 help="The target ref that is transitively tracked by the "
+                 "local branch this patch comes from.")
+parser.add_option("--cq_dry_run", action="store_true",
+                  help="Send the patchset to do a CQ dry run right after "
+                       "upload.")
+parser.add_option("--depends_on_patchset", action="store",
+                  dest="depends_on_patchset",
+                  help="The uploaded patchset this patchset depends on. The "
+                       "value will be in this format- issue_num:patchset_num")
+group.add_option("--download_base", action="store_true",
+                 dest="download_base", default=False,
+                 help="Base files will be downloaded by the server "
+                 "(side-by-side diffs may not work on files with CRs).")
+group.add_option("--rev", action="store", dest="revision",
+                 metavar="REV", default=None,
+                 help="Base revision/branch/tree to diff against. Use "
+                      "rev1:rev2 range to review already committed changeset.")
+group.add_option("--send_mail", action="store_true",
+                 dest="send_mail", default=False,
+                 help="Send notification email to reviewers.")
+group.add_option("-p", "--send_patch", action="store_true",
+                 dest="send_patch", default=False,
+                 help="Same as --send_mail, but include diff as an "
+                      "attachment, and prepend email subject with 'PATCH:'.")
+group.add_option("--vcs", action="store", dest="vcs",
+                 metavar="VCS", default=None,
+                 help=("Explicitly specify version control system (%s)"
+                       % ", ".join(VCS_SHORT_NAMES)))
+group.add_option("--emulate_svn_auto_props", action="store_true",
+                 dest="emulate_svn_auto_props", default=False,
+                 help=("Emulate Subversion's auto properties feature."))
+# Git-specific
+group = parser.add_option_group("Git-specific options")
+group.add_option("--git_similarity", action="store", dest="git_similarity",
+                 metavar="SIM", type="int", default=50,
+                 help=("Set the minimum similarity percentage for detecting "
+                       "renames and copies. See `git diff -C`. (default 50)."))
+group.add_option("--git_find_copies_harder", action="store_true", default=False,
+                 dest='git_find_copies_harder',
+                 help="Adds --find-copies-harder when seaching for copies")
+group.add_option("--git_no_find_copies", action="store_false", default=True,
+                 dest="git_find_copies",
+                 help=("Prevents git from looking for copies (default off)."))
+# Perforce-specific
+group = parser.add_option_group("Perforce-specific options "
+                                "(overrides P4 environment variables)")
+group.add_option("--p4_port", action="store", dest="p4_port",
+                 metavar="P4_PORT", default=None,
+                 help=("Perforce server and port (optional)"))
+group.add_option("--p4_changelist", action="store", dest="p4_changelist",
+                 metavar="P4_CHANGELIST", default=None,
+                 help=("Perforce changelist id"))
+group.add_option("--p4_client", action="store", dest="p4_client",
+                 metavar="P4_CLIENT", default=None,
+                 help=("Perforce client/workspace"))
+group.add_option("--p4_user", action="store", dest="p4_user",
+                 metavar="P4_USER", default=None,
+                 help=("Perforce user"))
+
+
+class KeyringCreds(object):
+  def __init__(self, server, host, email):
+    self.server = server
+    # Explicitly cast host to str to work around bug in old versions of Keyring
+    # (versions before 0.10). Even though newer versions of Keyring fix this,
+    # some modern linuxes (such as Ubuntu 12.04) still bundle a version with
+    # the bug.
+    self.host = str(host)
+    self.email = email
+    self.accounts_seen = set()
+
+  def GetUserCredentials(self):
+    """Prompts the user for a username and password.
+
+    Only use keyring on the initial call. If the keyring contains the wrong
+    password, we want to give the user a chance to enter another one.
+    """
+    # Create a local alias to the email variable to avoid Python's crazy
+    # scoping rules.
+    global keyring
+    email = self.email
+    if email is None:
+      email = GetEmail("Email (login for uploading to %s)" % self.server)
+    password = None
+    if keyring and not email in self.accounts_seen:
+      try:
+        password = keyring.get_password(self.host, email)
+      except:
+        # Sadly, we have to trap all errors here as
+        # gnomekeyring.IOError inherits from object. :/
+        print("Failed to get password from keyring")
+        keyring = None
+    if password is not None:
+      print("Using password from system keyring.")
+      self.accounts_seen.add(email)
+    else:
+      password = getpass.getpass("Password for %s: " % email)
+      if keyring:
+        answer = raw_input("Store password in system keyring?(y/N) ").strip()
+        if answer == "y":
+          keyring.set_password(self.host, email, password)
+          self.accounts_seen.add(email)
+    return (email, password)
+
+
+def GetRpcServer(server, auth_config=None, email=None):
+  """Returns an instance of an AbstractRpcServer.
+
+  Args:
+    server: String containing the review server URL.
+    auth_config: auth.AuthConfig tuple with OAuth2 configuration.
+    email: String containing user's email address [deprecated].
+
+  Returns:
+    A new HttpRpcServer, on which RPC calls can be made.
+  """
+  # If email is given as an empty string or no auth config is passed, then
+  # assume we want to make requests that do not need authentication. Bypass
+  # authentication by setting the auth_function to None.
+  if email == '' or not auth_config:
+    return HttpRpcServer(server, None)
+
+  # If this is the dev_appserver, use fake authentication.
+  host = server.lower()
+  if re.match(r'(http://)?localhost([:/]|$)', host):
+    if email is None:
+      email = "test@example.com"
+      LOGGER.info("Using debug user %s.  Override with --email" % email)
+    server = HttpRpcServer(
+        server,
+        lambda: (email, "password"),
+        extra_headers={"Cookie":
+                       'dev_appserver_login="%s:False"' % email},
+        save_cookies=auth_config.save_cookies,
+        account_type=AUTH_ACCOUNT_TYPE)
+    # Don't try to talk to ClientLogin.
+    server.authenticated = True
+    return server
+
+  if auth_config.use_oauth2:
+    auth_func = auth.get_authenticator_for_host(server, auth_config)
+  else:
+    auth_func = KeyringCreds(server, host, email).GetUserCredentials
+
+  # HACK(crbug.com/476690): Internal Rietveld is configured to require cookie
+  # auth for all paths except /bots/* (requests to /bots/* are authenticated
+  # with OAuth). /bots/* paths expose exact same API as /* (at least enough of
+  # it for depot_tools to work). So when using OAuth with internal Rietveld,
+  # silently prefix all requests with '/bots'.
+  request_path_prefix = ''
+  if auth_config.use_oauth2:
+    if not host.startswith(('http://', 'https://')):
+      host = 'https://' + host
+    parsed = urlparse.urlparse(host)
+    if parsed.netloc.endswith('.googleplex.com'):
+      request_path_prefix = '/bots'
+
+  return HttpRpcServer(
+      server,
+      auth_func,
+      request_path_prefix=request_path_prefix,
+      save_cookies=auth_config.save_cookies,
+      account_type=AUTH_ACCOUNT_TYPE)
+
+
+def EncodeMultipartFormData(fields, files):
+  """Encode form fields for multipart/form-data.
+
+  Args:
+    fields: A sequence of (name, value) elements for regular form fields.
+    files: A sequence of (name, filename, value) elements for data to be
+           uploaded as files.
+  Returns:
+    (content_type, body) ready for httplib.HTTP instance.
+
+  Source:
+    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/146306
+  """
+  BOUNDARY = '-M-A-G-I-C---B-O-U-N-D-A-R-Y-%s-' % sum(hash(f) for f in files)
+  CRLF = '\r\n'
+  lines = []
+  for (key, value) in fields:
+    lines.append('--' + BOUNDARY)
+    lines.append('Content-Disposition: form-data; name="%s"' % key)
+    lines.append('')
+    if isinstance(value, unicode):
+      value = value.encode('utf-8')
+    lines.append(value)
+  for (key, filename, value) in files:
+    lines.append('--' + BOUNDARY)
+    lines.append('Content-Disposition: form-data; name="%s"; filename="%s"' %
+             (key, filename))
+    lines.append('Content-Type: %s' % GetContentType(filename))
+    lines.append('')
+    if isinstance(value, unicode):
+      value = value.encode('utf-8')
+    lines.append(value)
+  lines.append('--' + BOUNDARY + '--')
+  lines.append('')
+  body = CRLF.join(lines)
+  content_type = 'multipart/form-data; boundary=%s' % BOUNDARY
+  return content_type, body
+
+
+def GetContentType(filename):
+  """Helper to guess the content-type from the filename."""
+  return mimetypes.guess_type(filename)[0] or 'application/octet-stream'
+
+
+# Use a shell for subcommands on Windows to get a PATH search.
+use_shell = sys.platform.startswith("win")
+
+def RunShellWithReturnCodeAndStderr(command, universal_newlines=True,
+                                    env=os.environ):
+  """Run a command and return output from stdout, stderr and the return code.
+
+  Args:
+    command: Command to execute.
+    universal_newlines: Use universal_newlines flag (default: True).
+
+  Returns:
+    Tuple (stdout, stderr, return code)
+  """
+  LOGGER.info("Running %s", command)
+  env = env.copy()
+  env['LC_MESSAGES'] = 'C'
+  p = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                       shell=use_shell, universal_newlines=universal_newlines,
+                       env=env)
+  output, errout = p.communicate()
+  p.stdout.close()
+  p.stderr.close()
+  return output, errout, p.returncode
+
+def RunShellWithReturnCode(command, universal_newlines=True, env=os.environ):
+  """Run a command and return output from stdout and the return code."""
+  out, err, retcode = RunShellWithReturnCodeAndStderr(command,
+                           universal_newlines, env)
+  return out, retcode
+
+def RunShell(command, silent_ok=False, universal_newlines=True,
+             env=os.environ):
+  data, retcode = RunShellWithReturnCode(command, universal_newlines, env)
+  if retcode:
+    ErrorExit("Got error status from %s:\n%s" % (command, data))
+  if not silent_ok and not data:
+    ErrorExit("No output from %s" % command)
+  return data
+
+
+class VersionControlSystem(object):
+  """Abstract base class providing an interface to the VCS."""
+
+  def __init__(self, options):
+    """Constructor.
+
+    Args:
+      options: Command line options.
+    """
+    self.options = options
+
+  def GetGUID(self):
+    """Return string to distinguish the repository from others, for example to
+    query all opened review issues for it"""
+    raise NotImplementedError(
+        "abstract method -- subclass %s must override" % self.__class__)
+
+  def PostProcessDiff(self, diff):
+    """Return the diff with any special post processing this VCS needs, e.g.
+    to include an svn-style "Index:"."""
+    return diff
+
+  def GenerateDiff(self, args):
+    """Return the current diff as a string.
+
+    Args:
+      args: Extra arguments to pass to the diff command.
+    """
+    raise NotImplementedError(
+        "abstract method -- subclass %s must override" % self.__class__)
+
+  def GetUnknownFiles(self):
+    """Return a list of files unknown to the VCS."""
+    raise NotImplementedError(
+        "abstract method -- subclass %s must override" % self.__class__)
+
+  def CheckForUnknownFiles(self):
+    """Show an "are you sure?" prompt if there are unknown files."""
+    unknown_files = self.GetUnknownFiles()
+    if unknown_files:
+      print("The following files are not added to version control:")
+      for line in unknown_files:
+        print(line)
+      prompt = "Are you sure to continue?(y/N) "
+      answer = raw_input(prompt).strip()
+      if answer != "y":
+        ErrorExit("User aborted")
+
+  def GetBaseFile(self, filename):
+    """Get the content of the upstream version of a file.
+
+    Returns:
+      A tuple (base_content, new_content, is_binary, status)
+        base_content: The contents of the base file.
+        new_content: For text files, this is empty.  For binary files, this is
+          the contents of the new file, since the diff output won't contain
+          information to reconstruct the current file.
+        is_binary: True iff the file is binary.
+        status: The status of the file.
+    """
+
+    raise NotImplementedError(
+        "abstract method -- subclass %s must override" % self.__class__)
+
+  def GetBaseFiles(self, diff):
+    """Helper that calls GetBase file for each file in the patch.
+
+    Returns:
+      A dictionary that maps from filename to GetBaseFile's tuple.  Filenames
+      are retrieved based on lines that start with "Index:" or
+      "Property changes on:".
+    """
+    files = {}
+    for line in diff.splitlines(True):
+      if line.startswith('Index:') or line.startswith('Property changes on:'):
+        unused, filename = line.split(':', 1)
+        # On Windows if a file has property changes its filename uses '\'
+        # instead of '/'.
+        filename = filename.strip().replace('\\', '/')
+        files[filename] = self.GetBaseFile(filename)
+    return files
+
+  def UploadBaseFiles(self, issue, rpc_server, patch_list, patchset, options,
+                      files):
+    """Uploads the base files (and if necessary, the current ones as well)."""
+
+    def UploadFile(filename, file_id, content, is_binary, status, is_base):
+      """Uploads a file to the server."""
+      file_too_large = False
+      if is_base:
+        type = "base"
+      else:
+        type = "current"
+      if len(content) > MAX_UPLOAD_SIZE:
+        result = ("Not uploading the %s file for %s because it's too large." %
+            (type, filename))
+        file_too_large = True
+        content = ""
+      elif options.verbose:
+        result = "Uploading %s file for %s" % (type, filename)
+      checksum = md5(content).hexdigest()
+      url = "/%d/upload_content/%d/%d" % (int(issue), int(patchset), file_id)
+      form_fields = [("filename", filename),
+                     ("status", status),
+                     ("checksum", checksum),
+                     ("is_binary", str(is_binary)),
+                     ("is_current", str(not is_base)),
+                    ]
+      if file_too_large:
+        form_fields.append(("file_too_large", "1"))
+      if options.email:
+        form_fields.append(("user", options.email))
+      ctype, body = EncodeMultipartFormData(form_fields,
+                                            [("data", filename, content)])
+      try:
+        response_body = rpc_server.Send(url, body, content_type=ctype)
+      except urllib2.HTTPError as e:
+        response_body = ("Failed to upload file for %s. Got %d status code." %
+            (filename, e.code))
+
+      if not response_body.startswith("OK"):
+        StatusUpdate("  --> %s" % response_body)
+        sys.exit(1)
+
+      return result
+
+    patches = dict()
+    [patches.setdefault(v, k) for k, v in patch_list]
+
+    def uploadAttempt():
+      threads = []
+      thread_pool = ThreadPool(options.num_upload_threads)
+
+      for filename in patches.keys():
+        base_content, new_content, is_binary, status = files[filename]
+        file_id_str = patches.get(filename)
+        if file_id_str.find("nobase") != -1:
+          base_content = None
+          file_id_str = file_id_str[file_id_str.rfind("_") + 1:]
+        file_id = int(file_id_str)
+        if base_content != None:
+          t = thread_pool.apply_async(UploadFile, args=(filename,
+              file_id, base_content, is_binary, status, True))
+          threads.append(t)
+        if new_content != None:
+          t = thread_pool.apply_async(UploadFile, args=(filename,
+              file_id, new_content, is_binary, status, False))
+          threads.append(t)
+
+      for t in threads:
+        print(t.get(timeout=UPLOAD_TIMEOUT))
+
+    success = False
+    for _ in range(MAX_UPLOAD_ATTEMPTS):
+      try:
+        uploadAttempt()
+        success = True
+        break
+      except multiprocessing.TimeoutError:
+        LOGGER.warning('Timeout error while uploading, retrying...')
+
+    if not success:
+      raise IOError(
+          '%d consecutive timeout errors, aborting!' % MAX_UPLOAD_ATTEMPTS)
+
+  def IsImage(self, filename):
+    """Returns true if the filename has an image extension."""
+    mimetype =  mimetypes.guess_type(filename)[0]
+    if not mimetype:
+      return False
+    return (mimetype.startswith("image/") and
+            not mimetype.startswith("image/svg"))
+
+  def IsBinaryData(self, data):
+    """Returns true if data contains a null byte."""
+    # Derived from how Mercurial's heuristic, see
+    # http://selenic.com/hg/file/848a6658069e/mercurial/util.py#l229
+    return bool(data and "\0" in data)
+
+  def GetMostRecentCommitSummary(self):
+    """Returns a one line summary of the current commit."""
+    return ""
+
+
+class SubversionVCS(VersionControlSystem):
+  """Implementation of the VersionControlSystem interface for Subversion."""
+
+  def __init__(self, options):
+    super(SubversionVCS, self).__init__(options)
+    if self.options.revision:
+      match = re.match(r"(\d+)(:(\d+))?", self.options.revision)
+      if not match:
+        ErrorExit("Invalid Subversion revision %s." % self.options.revision)
+      self.rev_start = match.group(1)
+      self.rev_end = match.group(3)
+    else:
+      self.rev_start = self.rev_end = None
+    # Cache output from "svn list -r REVNO dirname".
+    # Keys: dirname, Values: 2-tuple (ouput for start rev and end rev).
+    self.svnls_cache = {}
+    # Base URL is required to fetch files deleted in an older revision.
+    # Result is cached to not guess it over and over again in GetBaseFile().
+    required = self.options.download_base or self.options.revision is not None
+    self.svn_base = self._GuessBase(required)
+
+  def GetGUID(self):
+    return self._GetInfo("Repository UUID")
+
+  def GuessBase(self, required):
+    """Wrapper for _GuessBase."""
+    return self.svn_base
+
+  def _GuessBase(self, required):
+    """Returns base URL for current diff.
+
+    Args:
+      required: If true, exits if the url can't be guessed, otherwise None is
+        returned.
+    """
+    url = self._GetInfo("URL")
+    if url:
+      scheme, netloc, path, params, query, fragment = urlparse.urlparse(url)
+      guess = ""
+      # TODO(anatoli) - repository specific hacks should be handled by server
+      if netloc == "svn.python.org" and scheme == "svn+ssh":
+        path = "projects" + path
+        scheme = "http"
+        guess = "Python "
+      elif netloc.endswith(".googlecode.com"):
+        scheme = "http"
+        guess = "Google Code "
+      path = path + "/"
+      base = urlparse.urlunparse((scheme, netloc, path, params,
+                                  query, fragment))
+      LOGGER.info("Guessed %sbase = %s", guess, base)
+      return base
+    if required:
+      ErrorExit("Can't find URL in output from svn info")
+    return None
+
+  def _GetInfo(self, key):
+    """Parses 'svn info' for current dir. Returns value for key or None"""
+    for line in RunShell(["svn", "info"]).splitlines():
+      if line.startswith(key + ": "):
+        return line.split(":", 1)[1].strip()
+
+  def _EscapeFilename(self, filename):
+    """Escapes filename for SVN commands."""
+    if "@" in filename and not filename.endswith("@"):
+      filename = "%s@" % filename
+    return filename
+
+  def GenerateDiff(self, args):
+    cmd = ["svn", "diff"]
+    if self.options.revision:
+      cmd += ["-r", self.options.revision]
+    cmd.extend(args)
+    data = RunShell(cmd)
+    count = 0
+    for line in data.splitlines():
+      if line.startswith("Index:") or line.startswith("Property changes on:"):
+        count += 1
+        LOGGER.info(line)
+    if not count:
+      ErrorExit("No valid patches found in output from svn diff")
+    return data
+
+  def _CollapseKeywords(self, content, keyword_str):
+    """Collapses SVN keywords."""
+    # svn cat translates keywords but svn diff doesn't. As a result of this
+    # behavior patching.PatchChunks() fails with a chunk mismatch error.
+    # This part was originally written by the Review Board development team
+    # who had the same problem (http://reviews.review-board.org/r/276/).
+    # Mapping of keywords to known aliases
+    svn_keywords = {
+      # Standard keywords
+      'Date':                ['Date', 'LastChangedDate'],
+      'Revision':            ['Revision', 'LastChangedRevision', 'Rev'],
+      'Author':              ['Author', 'LastChangedBy'],
+      'HeadURL':             ['HeadURL', 'URL'],
+      'Id':                  ['Id'],
+
+      # Aliases
+      'LastChangedDate':     ['LastChangedDate', 'Date'],
+      'LastChangedRevision': ['LastChangedRevision', 'Rev', 'Revision'],
+      'LastChangedBy':       ['LastChangedBy', 'Author'],
+      'URL':                 ['URL', 'HeadURL'],
+    }
+
+    def repl(m):
+      if m.group(2):
+        return "$%s::%s$" % (m.group(1), " " * len(m.group(3)))
+      return "$%s$" % m.group(1)
+
+    keywords = [keyword
+                for name in keyword_str.split(" ")
+                for keyword in svn_keywords.get(name, [])]
+    return re.sub(r"\$(%s):(:?)([^\$]+)\$" % '|'.join(keywords), repl, content)
+
+  def GetUnknownFiles(self):
+    status = RunShell(["svn", "status", "--ignore-externals"], silent_ok=True)
+    unknown_files = []
+    for line in status.split("\n"):
+      if line and line[0] == "?":
+        unknown_files.append(line)
+    return unknown_files
+
+  def ReadFile(self, filename):
+    """Returns the contents of a file."""
+    file = open(filename, 'rb')
+    result = ""
+    try:
+      result = file.read()
+    finally:
+      file.close()
+    return result
+
+  def GetStatus(self, filename):
+    """Returns the status of a file."""
+    if not self.options.revision:
+      status = RunShell(["svn", "status", "--ignore-externals",
+                         self._EscapeFilename(filename)])
+      if not status:
+        ErrorExit("svn status returned no output for %s" % filename)
+      status_lines = status.splitlines()
+      # If file is in a cl, the output will begin with
+      # "\n--- Changelist 'cl_name':\n".  See
+      # http://svn.collab.net/repos/svn/trunk/notes/changelist-design.txt
+      if (len(status_lines) == 3 and
+          not status_lines[0] and
+          status_lines[1].startswith("--- Changelist")):
+        status = status_lines[2]
+      else:
+        status = status_lines[0]
+    # If we have a revision to diff against we need to run "svn list"
+    # for the old and the new revision and compare the results to get
+    # the correct status for a file.
+    else:
+      dirname, relfilename = os.path.split(filename)
+      if dirname not in self.svnls_cache:
+        cmd = ["svn", "list", "-r", self.rev_start,
+               self._EscapeFilename(dirname) or "."]
+        out, err, returncode = RunShellWithReturnCodeAndStderr(cmd)
+        if returncode:
+          # Directory might not yet exist at start revison
+          # svn: Unable to find repository location for 'abc' in revision nnn
+          if re.match('^svn: Unable to find repository location '
+                      'for .+ in revision \d+', err):
+            old_files = ()
+          else:
+            ErrorExit("Failed to get status for %s:\n%s" % (filename, err))
+        else:
+          old_files = out.splitlines()
+        args = ["svn", "list"]
+        if self.rev_end:
+          args += ["-r", self.rev_end]
+        cmd = args + [self._EscapeFilename(dirname) or "."]
+        out, returncode = RunShellWithReturnCode(cmd)
+        if returncode:
+          ErrorExit("Failed to run command %s" % cmd)
+        self.svnls_cache[dirname] = (old_files, out.splitlines())
+      old_files, new_files = self.svnls_cache[dirname]
+      if relfilename in old_files and relfilename not in new_files:
+        status = "D   "
+      elif relfilename in old_files and relfilename in new_files:
+        status = "M   "
+      else:
+        status = "A   "
+    return status
+
+  def GetBaseFile(self, filename):
+    status = self.GetStatus(filename)
+    base_content = None
+    new_content = None
+
+    # If a file is copied its status will be "A  +", which signifies
+    # "addition-with-history".  See "svn st" for more information.  We need to
+    # upload the original file or else diff parsing will fail if the file was
+    # edited.
+    if status[0] == "A" and status[3] != "+":
+      # We'll need to upload the new content if we're adding a binary file
+      # since diff's output won't contain it.
+      mimetype = RunShell(["svn", "propget", "svn:mime-type",
+                           self._EscapeFilename(filename)], silent_ok=True)
+      base_content = ""
+      is_binary = bool(mimetype) and not mimetype.startswith("text/")
+      if is_binary:
+        new_content = self.ReadFile(filename)
+    elif (status[0] in ("M", "D", "R") or
+          (status[0] == "A" and status[3] == "+") or  # Copied file.
+          (status[0] == " " and status[1] == "M")):  # Property change.
+      args = []
+      if self.options.revision:
+        # filename must not be escaped. We already add an ampersand here.
+        url = "%s/%s@%s" % (self.svn_base, filename, self.rev_start)
+      else:
+        # Don't change filename, it's needed later.
+        url = filename
+        args += ["-r", "BASE"]
+      cmd = ["svn"] + args + ["propget", "svn:mime-type", url]
+      mimetype, returncode = RunShellWithReturnCode(cmd)
+      if returncode:
+        # File does not exist in the requested revision.
+        # Reset mimetype, it contains an error message.
+        mimetype = ""
+      else:
+        mimetype = mimetype.strip()
+      get_base = False
+      # this test for binary is exactly the test prescribed by the
+      # official SVN docs at
+      # http://subversion.apache.org/faq.html#binary-files
+      is_binary = (bool(mimetype) and
+        not mimetype.startswith("text/") and
+        mimetype not in ("image/x-xbitmap", "image/x-xpixmap"))
+      if status[0] == " ":
+        # Empty base content just to force an upload.
+        base_content = ""
+      elif is_binary:
+        get_base = True
+        if status[0] == "M":
+          if not self.rev_end:
+            new_content = self.ReadFile(filename)
+          else:
+            url = "%s/%s@%s" % (self.svn_base, filename, self.rev_end)
+            new_content = RunShell(["svn", "cat", url],
+                                   universal_newlines=True, silent_ok=True)
+      else:
+        get_base = True
+
+      if get_base:
+        if is_binary:
+          universal_newlines = False
+        else:
+          universal_newlines = True
+        if self.rev_start:
+          # "svn cat -r REV delete_file.txt" doesn't work. cat requires
+          # the full URL with "@REV" appended instead of using "-r" option.
+          url = "%s/%s@%s" % (self.svn_base, filename, self.rev_start)
+          base_content = RunShell(["svn", "cat", url],
+                                  universal_newlines=universal_newlines,
+                                  silent_ok=True)
+        else:
+          base_content, ret_code = RunShellWithReturnCode(
+            ["svn", "cat", self._EscapeFilename(filename)],
+            universal_newlines=universal_newlines)
+          if ret_code and status[0] == "R":
+            # It's a replaced file without local history (see issue208).
+            # The base file needs to be fetched from the server.
+            url = "%s/%s" % (self.svn_base, filename)
+            base_content = RunShell(["svn", "cat", url],
+                                    universal_newlines=universal_newlines,
+                                    silent_ok=True)
+          elif ret_code:
+            ErrorExit("Got error status from 'svn cat %s'" % filename)
+        if not is_binary:
+          args = []
+          if self.rev_start:
+            url = "%s/%s@%s" % (self.svn_base, filename, self.rev_start)
+          else:
+            url = filename
+            args += ["-r", "BASE"]
+          cmd = ["svn"] + args + ["propget", "svn:keywords", url]
+          keywords, returncode = RunShellWithReturnCode(cmd)
+          if keywords and not returncode:
+            base_content = self._CollapseKeywords(base_content, keywords)
+    else:
+      StatusUpdate("svn status returned unexpected output: %s" % status)
+      sys.exit(1)
+    return base_content, new_content, is_binary, status[0:5]
+
+
+class GitVCS(VersionControlSystem):
+  """Implementation of the VersionControlSystem interface for Git."""
+
+  def __init__(self, options):
+    super(GitVCS, self).__init__(options)
+    # Map of filename -> (hash before, hash after) of base file.
+    # Hashes for "no such file" are represented as None.
+    self.hashes = {}
+    # Map of new filename -> old filename for renames.
+    self.renames = {}
+
+  def GetGUID(self):
+    remote, retcode = RunShellWithReturnCode(
+        "git config remote.origin.url".split())
+    if not retcode:
+      return remote.strip()
+    revlist = RunShell("git rev-list --parents HEAD".split()).splitlines()
+    # M-A: Return the 1st root hash, there could be multiple when a
+    # subtree is merged. In that case, more analysis would need to
+    # be done to figure out which HEAD is the 'most representative'.
+    for r in revlist:
+      if ' ' not in r:
+        return r
+
+  def PostProcessDiff(self, gitdiff):
+    """Converts the diff output to include an svn-style "Index:" line as well
+    as record the hashes of the files, so we can upload them along with our
+    diff."""
+    # Special used by git to indicate "no such content".
+    NULL_HASH = "0"*40
+
+    def IsFileNew(filename):
+      return filename in self.hashes and self.hashes[filename][0] is None
+
+    def AddSubversionPropertyChange(filename):
+      """Add svn's property change information into the patch if given file is
+      new file.
+
+      We use Subversion's auto-props setting to retrieve its property.
+      See http://svnbook.red-bean.com/en/1.1/ch07.html#svn-ch-7-sect-1.3.2 for
+      Subversion's [auto-props] setting.
+      """
+      if self.options.emulate_svn_auto_props and IsFileNew(filename):
+        svnprops = GetSubversionPropertyChanges(filename)
+        if svnprops:
+          svndiff.append("\n" + svnprops + "\n")
+
+    svndiff = []
+    filecount = 0
+    filename = None
+    for line in gitdiff.splitlines():
+      match = re.match(r"diff --git a/(.*) b/(.*)$", line)
+      if match:
+        # Add auto property here for previously seen file.
+        if filename is not None:
+          AddSubversionPropertyChange(filename)
+        filecount += 1
+        # Intentionally use the "after" filename so we can show renames.
+        filename = match.group(2)
+        svndiff.append("Index: %s\n" % filename)
+        if match.group(1) != match.group(2):
+          self.renames[match.group(2)] = match.group(1)
+      else:
+        # The "index" line in a git diff looks like this (long hashes elided):
+        #   index 82c0d44..b2cee3f 100755
+        # We want to save the left hash, as that identifies the base file.
+        match = re.match(r"index (\w+)\.\.(\w+)", line)
+        if match:
+          before, after = (match.group(1), match.group(2))
+          if before == NULL_HASH:
+            before = None
+          if after == NULL_HASH:
+            after = None
+          self.hashes[filename] = (before, after)
+      svndiff.append(line + "\n")
+    if not filecount:
+      ErrorExit("No valid patches found in output from git diff")
+    # Add auto property for the last seen file.
+    assert filename is not None
+    AddSubversionPropertyChange(filename)
+    return "".join(svndiff)
+
+  def GenerateDiff(self, extra_args):
+    extra_args = extra_args[:]
+    if self.options.revision:
+      if ":" in self.options.revision:
+        extra_args = self.options.revision.split(":", 1) + extra_args
+      else:
+        extra_args = [self.options.revision] + extra_args
+
+    # --no-ext-diff is broken in some versions of Git, so try to work around
+    # this by overriding the environment (but there is still a problem if the
+    # git config key "diff.external" is used).
+    env = os.environ.copy()
+    if "GIT_EXTERNAL_DIFF" in env:
+      del env["GIT_EXTERNAL_DIFF"]
+    # 'cat' is a magical git string that disables pagers on all platforms.
+    env["GIT_PAGER"] = "cat"
+
+    # -M/-C will not print the diff for the deleted file when a file is renamed.
+    # This is confusing because the original file will not be shown on the
+    # review when a file is renamed. So, get a diff with ONLY deletes, then
+    # append a diff (with rename detection), without deletes.
+    cmd = [
+        "git", "diff", "--no-color", "--no-ext-diff", "--full-index",
+        "--ignore-submodules", "--src-prefix=a/", "--dst-prefix=b/",
+    ]
+    diff = RunShell(
+        cmd + ["--no-renames", "--diff-filter=D"] + extra_args,
+        env=env, silent_ok=True)
+    assert 0 <= self.options.git_similarity <= 100
+    if self.options.git_find_copies:
+      similarity_options = ["-l100000", "-C%d%%" % self.options.git_similarity]
+      if self.options.git_find_copies_harder:
+        similarity_options.append("--find-copies-harder")
+    else:
+      similarity_options = ["-M%d%%" % self.options.git_similarity ]
+    diff += RunShell(
+        cmd + ["--diff-filter=AMCRT"] + similarity_options + extra_args,
+        env=env, silent_ok=True)
+
+    # The CL could be only file deletion or not. So accept silent diff for both
+    # commands then check for an empty diff manually.
+    if not diff:
+      ErrorExit("No output from %s" % (cmd + extra_args))
+    return diff
+
+  def GetUnknownFiles(self):
+    status = RunShell(["git", "ls-files", "--exclude-standard", "--others"],
+                      silent_ok=True)
+    return status.splitlines()
+
+  def GetFileContent(self, file_hash):
+    """Returns the content of a file identified by its git hash."""
+    data, retcode = RunShellWithReturnCode(["git", "show", file_hash],
+                                            universal_newlines=False)
+    if retcode:
+      ErrorExit("Got error status from 'git show %s'" % file_hash)
+    return data
+
+  def GetBaseFile(self, filename):
+    hash_before, hash_after = self.hashes.get(filename, (None,None))
+    base_content = None
+    new_content = None
+    status = None
+
+    if filename in self.renames:
+      status = "A +"  # Match svn attribute name for renames.
+      if filename not in self.hashes:
+        # If a rename doesn't change the content, we never get a hash.
+        base_content = RunShell(
+            ["git", "show", "HEAD:" + filename], silent_ok=True,
+            universal_newlines=False)
+    elif not hash_before:
+      status = "A"
+      base_content = ""
+    elif not hash_after:
+      status = "D"
+    else:
+      status = "M"
+
+    # Grab the before/after content if we need it.
+    # Grab the base content if we don't have it already.
+    if base_content is None and hash_before:
+      base_content = self.GetFileContent(hash_before)
+
+    is_binary = self.IsImage(filename)
+    if base_content:
+      is_binary = is_binary or self.IsBinaryData(base_content)
+
+    # Only include the "after" file if it's an image; otherwise it
+    # it is reconstructed from the diff.
+    if hash_after:
+      new_content = self.GetFileContent(hash_after)
+      is_binary = is_binary or self.IsBinaryData(new_content)
+      if not is_binary:
+        new_content = None
+    return (base_content, new_content, is_binary, status)
+
+  def GetMostRecentCommitSummary(self):
+    return RunShell(["git", "log", "-1", "--format=%s"], silent_ok=True).strip()
+
+
+class CVSVCS(VersionControlSystem):
+  """Implementation of the VersionControlSystem interface for CVS."""
+
+  def __init__(self, options):
+    super(CVSVCS, self).__init__(options)
+
+  def GetGUID(self):
+    """For now we don't know how to get repository ID for CVS"""
+    return
+
+  def GetOriginalContent_(self, filename):
+    RunShell(["cvs", "up", filename], silent_ok=True)
+    # TODO need detect file content encoding
+    content = open(filename).read()
+    return content.replace("\r\n", "\n")
+
+  def GetBaseFile(self, filename):
+    base_content = None
+    new_content = None
+    status = "A"
+
+    output, retcode = RunShellWithReturnCode(["cvs", "status", filename])
+    if retcode:
+      ErrorExit("Got error status from 'cvs status %s'" % filename)
+
+    if output.find("Status: Locally Modified") != -1:
+      status = "M"
+      temp_filename = "%s.tmp123" % filename
+      os.rename(filename, temp_filename)
+      base_content = self.GetOriginalContent_(filename)
+      os.rename(temp_filename, filename)
+    elif output.find("Status: Locally Added"):
+      status = "A"
+      base_content = ""
+    elif output.find("Status: Needs Checkout"):
+      status = "D"
+      base_content = self.GetOriginalContent_(filename)
+
+    return (base_content, new_content, self.IsBinaryData(base_content), status)
+
+  def GenerateDiff(self, extra_args):
+    cmd = ["cvs", "diff", "-u", "-N"]
+    if self.options.revision:
+      cmd += ["-r", self.options.revision]
+
+    cmd.extend(extra_args)
+    data, retcode = RunShellWithReturnCode(cmd)
+    count = 0
+    if retcode in [0, 1]:
+      for line in data.splitlines():
+        if line.startswith("Index:"):
+          count += 1
+          LOGGER.info(line)
+
+    if not count:
+      ErrorExit("No valid patches found in output from cvs diff")
+
+    return data
+
+  def GetUnknownFiles(self):
+    data, retcode = RunShellWithReturnCode(["cvs", "diff"])
+    if retcode not in [0, 1]:
+      ErrorExit("Got error status from 'cvs diff':\n%s" % (data,))
+    unknown_files = []
+    for line in data.split("\n"):
+      if line and line[0] == "?":
+        unknown_files.append(line)
+    return unknown_files
+
+class MercurialVCS(VersionControlSystem):
+  """Implementation of the VersionControlSystem interface for Mercurial."""
+
+  def __init__(self, options, repo_dir):
+    super(MercurialVCS, self).__init__(options)
+    # Absolute path to repository (we can be in a subdir)
+    self.repo_dir = os.path.normpath(repo_dir)
+    # Compute the subdir
+    cwd = os.path.normpath(os.getcwd())
+    assert cwd.startswith(self.repo_dir)
+    self.subdir = cwd[len(self.repo_dir):].lstrip(r"\/")
+    if self.options.revision:
+      self.base_rev = self.options.revision
+    else:
+      self.base_rev = RunShell(["hg", "parent", "-q"]).split(':')[1].strip()
+
+  def GetGUID(self):
+    # See chapter "Uniquely identifying a repository"
+    # http://hgbook.red-bean.com/read/customizing-the-output-of-mercurial.html
+    info = RunShell("hg log -r0 --template {node}".split())
+    return info.strip()
+
+  def _GetRelPath(self, filename):
+    """Get relative path of a file according to the current directory,
+    given its logical path in the repo."""
+    absname = os.path.join(self.repo_dir, filename)
+    return os.path.relpath(absname)
+
+  def GenerateDiff(self, extra_args):
+    cmd = ["hg", "diff", "--git", "-r", self.base_rev] + extra_args
+    data = RunShell(cmd, silent_ok=True)
+    svndiff = []
+    filecount = 0
+    for line in data.splitlines():
+      m = re.match("diff --git a/(\S+) b/(\S+)", line)
+      if m:
+        # Modify line to make it look like as it comes from svn diff.
+        # With this modification no changes on the server side are required
+        # to make upload.py work with Mercurial repos.
+        # NOTE: for proper handling of moved/copied files, we have to use
+        # the second filename.
+        filename = m.group(2)
+        svndiff.append("Index: %s" % filename)
+        svndiff.append("=" * 67)
+        filecount += 1
+        LOGGER.info(line)
+      else:
+        svndiff.append(line)
+    if not filecount:
+      ErrorExit("No valid patches found in output from hg diff")
+    return "\n".join(svndiff) + "\n"
+
+  def GetUnknownFiles(self):
+    """Return a list of files unknown to the VCS."""
+    args = []
+    status = RunShell(["hg", "status", "--rev", self.base_rev, "-u", "."],
+        silent_ok=True)
+    unknown_files = []
+    for line in status.splitlines():
+      st, fn = line.split(" ", 1)
+      if st == "?":
+        unknown_files.append(fn)
+    return unknown_files
+
+  def GetBaseFile(self, filename):
+    # "hg status" and "hg cat" both take a path relative to the current subdir,
+    # but "hg diff" has given us the path relative to the repo root.
+    base_content = ""
+    new_content = None
+    is_binary = False
+    oldrelpath = relpath = self._GetRelPath(filename)
+    # "hg status -C" returns two lines for moved/copied files, one otherwise
+    out = RunShell(["hg", "status", "-C", "--rev", self.base_rev, relpath])
+    out = out.splitlines()
+    # HACK: strip error message about missing file/directory if it isn't in
+    # the working copy
+    if out[0].startswith('%s: ' % relpath):
+      out = out[1:]
+    status, _ = out[0].split(' ', 1)
+    if len(out) > 1 and status == "A":
+      # Moved/copied => considered as modified, use old filename to
+      # retrieve base contents
+      oldrelpath = out[1].strip()
+      status = "M"
+    if ":" in self.base_rev:
+      base_rev = self.base_rev.split(":", 1)[0]
+    else:
+      base_rev = self.base_rev
+    if status != "A":
+      base_content = RunShell(["hg", "cat", "-r", base_rev, oldrelpath],
+        silent_ok=True)
+      is_binary = self.IsBinaryData(base_content)
+    if status != "R":
+      new_content = open(relpath, "rb").read()
+      is_binary = is_binary or self.IsBinaryData(new_content)
+    if is_binary and base_content:
+      # Fetch again without converting newlines
+      base_content = RunShell(["hg", "cat", "-r", base_rev, oldrelpath],
+        silent_ok=True, universal_newlines=False)
+    if not is_binary:
+      new_content = None
+    return base_content, new_content, is_binary, status
+
+
+class PerforceVCS(VersionControlSystem):
+  """Implementation of the VersionControlSystem interface for Perforce."""
+
+  def __init__(self, options):
+
+    def ConfirmLogin():
+      # Make sure we have a valid perforce session
+      while True:
+        data, retcode = self.RunPerforceCommandWithReturnCode(
+            ["login", "-s"], marshal_output=True)
+        if not data:
+          ErrorExit("Error checking perforce login")
+        if not retcode and (not "code" in data or data["code"] != "error"):
+          break
+        print("Enter perforce password: ")
+        self.RunPerforceCommandWithReturnCode(["login"])
+
+    super(PerforceVCS, self).__init__(options)
+
+    self.p4_changelist = options.p4_changelist
+    if not self.p4_changelist:
+      ErrorExit("A changelist id is required")
+    if (options.revision):
+      ErrorExit("--rev is not supported for perforce")
+
+    self.p4_port = options.p4_port
+    self.p4_client = options.p4_client
+    self.p4_user = options.p4_user
+
+    ConfirmLogin()
+
+    if not options.title:
+      description = self.RunPerforceCommand(["describe", self.p4_changelist],
+                                            marshal_output=True)
+      if description and "desc" in description:
+        # Rietveld doesn't support multi-line descriptions
+        raw_title = description["desc"].strip()
+        lines = raw_title.splitlines()
+        if len(lines):
+          options.title = lines[0]
+
+  def GetGUID(self):
+    """For now we don't know how to get repository ID for Perforce"""
+    return
+
+  def RunPerforceCommandWithReturnCode(self, extra_args, marshal_output=False,
+                                       universal_newlines=True):
+    args = ["p4"]
+    if marshal_output:
+      # -G makes perforce format its output as marshalled python objects
+      args.extend(["-G"])
+    if self.p4_port:
+      args.extend(["-p", self.p4_port])
+    if self.p4_client:
+      args.extend(["-c", self.p4_client])
+    if self.p4_user:
+      args.extend(["-u", self.p4_user])
+    args.extend(extra_args)
+
+    data, retcode = RunShellWithReturnCode(
+        args, universal_newlines=universal_newlines)
+    if marshal_output and data:
+      data = marshal.loads(data)
+    return data, retcode
+
+  def RunPerforceCommand(self, extra_args, marshal_output=False,
+                         universal_newlines=True):
+    # This might be a good place to cache call results, since things like
+    # describe or fstat might get called repeatedly.
+    data, retcode = self.RunPerforceCommandWithReturnCode(
+        extra_args, marshal_output, universal_newlines)
+    if retcode:
+      ErrorExit("Got error status from %s:\n%s" % (extra_args, data))
+    return data
+
+  def GetFileProperties(self, property_key_prefix = "", command = "describe"):
+    description = self.RunPerforceCommand(["describe", self.p4_changelist],
+                                          marshal_output=True)
+
+    changed_files = {}
+    file_index = 0
+    # Try depotFile0, depotFile1, ... until we don't find a match
+    while True:
+      file_key = "depotFile%d" % file_index
+      if file_key in description:
+        filename = description[file_key]
+        change_type = description[property_key_prefix + str(file_index)]
+        changed_files[filename] = change_type
+        file_index += 1
+      else:
+        break
+    return changed_files
+
+  def GetChangedFiles(self):
+    return self.GetFileProperties("action")
+
+  def GetUnknownFiles(self):
+    # Perforce doesn't detect new files, they have to be explicitly added
+    return []
+
+  def IsBaseBinary(self, filename):
+    base_filename = self.GetBaseFilename(filename)
+    return self.IsBinaryHelper(base_filename, "files")
+
+  def IsPendingBinary(self, filename):
+    return self.IsBinaryHelper(filename, "describe")
+
+  def IsBinaryHelper(self, filename, command):
+    file_types = self.GetFileProperties("type", command)
+    if not filename in file_types:
+      ErrorExit("Trying to check binary status of unknown file %s." % filename)
+    # This treats symlinks, macintosh resource files, temporary objects, and
+    # unicode as binary. See the Perforce docs for more details:
+    # http://www.perforce.com/perforce/doc.current/manuals/cmdref/o.ftypes.html
+    return not file_types[filename].endswith("text")
+
+  def GetFileContent(self, filename, revision, is_binary):
+    file_arg = filename
+    if revision:
+      file_arg += "#" + revision
+    # -q suppresses the initial line that displays the filename and revision
+    return self.RunPerforceCommand(["print", "-q", file_arg],
+                                   universal_newlines=not is_binary)
+
+  def GetBaseFilename(self, filename):
+    actionsWithDifferentBases = [
+        "move/add", # p4 move
+        "branch", # p4 integrate (to a new file), similar to hg "add"
+        "add", # p4 integrate (to a new file), after modifying the new file
+    ]
+
+    # We only see a different base for "add" if this is a downgraded branch
+    # after a file was branched (integrated), then edited.
+    if self.GetAction(filename) in actionsWithDifferentBases:
+      # -Or shows information about pending integrations/moves
+      fstat_result = self.RunPerforceCommand(["fstat", "-Or", filename],
+                                             marshal_output=True)
+
+      baseFileKey = "resolveFromFile0" # I think it's safe to use only file0
+      if baseFileKey in fstat_result:
+        return fstat_result[baseFileKey]
+
+    return filename
+
+  def GetBaseRevision(self, filename):
+    base_filename = self.GetBaseFilename(filename)
+
+    have_result = self.RunPerforceCommand(["have", base_filename],
+                                          marshal_output=True)
+    if "haveRev" in have_result:
+      return have_result["haveRev"]
+
+  def GetLocalFilename(self, filename):
+    where = self.RunPerforceCommand(["where", filename], marshal_output=True)
+    if "path" in where:
+      return where["path"]
+
+  def GenerateDiff(self, args):
+    class DiffData:
+      def __init__(self, perforceVCS, filename, action):
+        self.perforceVCS = perforceVCS
+        self.filename = filename
+        self.action = action
+        self.base_filename = perforceVCS.GetBaseFilename(filename)
+
+        self.file_body = None
+        self.base_rev = None
+        self.prefix = None
+        self.working_copy = True
+        self.change_summary = None
+
+    def GenerateDiffHeader(diffData):
+      header = []
+      header.append("Index: %s" % diffData.filename)
+      header.append("=" * 67)
+
+      if diffData.base_filename != diffData.filename:
+        if diffData.action.startswith("move"):
+          verb = "rename"
+        else:
+          verb = "copy"
+        header.append("%s from %s" % (verb, diffData.base_filename))
+        header.append("%s to %s" % (verb, diffData.filename))
+
+      suffix = "\t(revision %s)" % diffData.base_rev
+      header.append("--- " + diffData.base_filename + suffix)
+      if diffData.working_copy:
+        suffix = "\t(working copy)"
+      header.append("+++ " + diffData.filename + suffix)
+      if diffData.change_summary:
+        header.append(diffData.change_summary)
+      return header
+
+    def GenerateMergeDiff(diffData, args):
+      # -du generates a unified diff, which is nearly svn format
+      diffData.file_body = self.RunPerforceCommand(
+          ["diff", "-du", diffData.filename] + args)
+      diffData.base_rev = self.GetBaseRevision(diffData.filename)
+      diffData.prefix = ""
+
+      # We have to replace p4's file status output (the lines starting
+      # with +++ or ---) to match svn's diff format
+      lines = diffData.file_body.splitlines()
+      first_good_line = 0
+      while (first_good_line < len(lines) and
+            not lines[first_good_line].startswith("@@")):
+        first_good_line += 1
+      diffData.file_body = "\n".join(lines[first_good_line:])
+      return diffData
+
+    def GenerateAddDiff(diffData):
+      fstat = self.RunPerforceCommand(["fstat", diffData.filename],
+                                      marshal_output=True)
+      if "headRev" in fstat:
+        diffData.base_rev = fstat["headRev"] # Re-adding a deleted file
+      else:
+        diffData.base_rev = "0" # Brand new file
+      diffData.working_copy = False
+      rel_path = self.GetLocalFilename(diffData.filename)
+      diffData.file_body = open(rel_path, 'r').read()
+      # Replicate svn's list of changed lines
+      line_count = len(diffData.file_body.splitlines())
+      diffData.change_summary = "@@ -0,0 +1"
+      if line_count > 1:
+        diffData.change_summary += ",%d" % line_count
+      diffData.change_summary += " @@"
+      diffData.prefix = "+"
+      return diffData
+
+    def GenerateDeleteDiff(diffData):
+      diffData.base_rev = self.GetBaseRevision(diffData.filename)
+      is_base_binary = self.IsBaseBinary(diffData.filename)
+      # For deletes, base_filename == filename
+      diffData.file_body = self.GetFileContent(diffData.base_filename,
+          None,
+          is_base_binary)
+      # Replicate svn's list of changed lines
+      line_count = len(diffData.file_body.splitlines())
+      diffData.change_summary = "@@ -1"
+      if line_count > 1:
+        diffData.change_summary += ",%d" % line_count
+      diffData.change_summary += " +0,0 @@"
+      diffData.prefix = "-"
+      return diffData
+
+    changed_files = self.GetChangedFiles()
+
+    svndiff = []
+    filecount = 0
+    for (filename, action) in changed_files.items():
+      svn_status = self.PerforceActionToSvnStatus(action)
+      if svn_status == "SKIP":
+        continue
+
+      diffData = DiffData(self, filename, action)
+      # Is it possible to diff a branched file? Stackoverflow says no:
+      # http://stackoverflow.com/questions/1771314/in-perforce-command-line-how-to-diff-a-file-reopened-for-add
+      if svn_status == "M":
+        diffData = GenerateMergeDiff(diffData, args)
+      elif svn_status == "A":
+        diffData = GenerateAddDiff(diffData)
+      elif svn_status == "D":
+        diffData = GenerateDeleteDiff(diffData)
+      else:
+        ErrorExit("Unknown file action %s (svn action %s)." % \
+                  (action, svn_status))
+
+      svndiff += GenerateDiffHeader(diffData)
+
+      for line in diffData.file_body.splitlines():
+        svndiff.append(diffData.prefix + line)
+      filecount += 1
+    if not filecount:
+      ErrorExit("No valid patches found in output from p4 diff")
+    return "\n".join(svndiff) + "\n"
+
+  def PerforceActionToSvnStatus(self, status):
+    # Mirroring the list at http://permalink.gmane.org/gmane.comp.version-control.mercurial.devel/28717
+    # Is there something more official?
+    return {
+            "add" : "A",
+            "branch" : "A",
+            "delete" : "D",
+            "edit" : "M", # Also includes changing file types.
+            "integrate" : "M",
+            "move/add" : "M",
+            "move/delete": "SKIP",
+            "purge" : "D", # How does a file's status become "purge"?
+            }[status]
+
+  def GetAction(self, filename):
+    changed_files = self.GetChangedFiles()
+    if not filename in changed_files:
+      ErrorExit("Trying to get base version of unknown file %s." % filename)
+
+    return changed_files[filename]
+
+  def GetBaseFile(self, filename):
+    base_filename = self.GetBaseFilename(filename)
+    base_content = ""
+    new_content = None
+
+    status = self.PerforceActionToSvnStatus(self.GetAction(filename))
+
+    if status != "A":
+      revision = self.GetBaseRevision(base_filename)
+      if not revision:
+        ErrorExit("Couldn't find base revision for file %s" % filename)
+      is_base_binary = self.IsBaseBinary(base_filename)
+      base_content = self.GetFileContent(base_filename,
+                                         revision,
+                                         is_base_binary)
+
+    is_binary = self.IsPendingBinary(filename)
+    if status != "D" and status != "SKIP":
+      relpath = self.GetLocalFilename(filename)
+      if is_binary:
+        new_content = open(relpath, "rb").read()
+
+    return base_content, new_content, is_binary, status
+
+# NOTE: The SplitPatch function is duplicated in engine.py, keep them in sync.
+def SplitPatch(data):
+  """Splits a patch into separate pieces for each file.
+
+  Args:
+    data: A string containing the output of svn diff.
+
+  Returns:
+    A list of 2-tuple (filename, text) where text is the svn diff output
+      pertaining to filename.
+  """
+  patches = []
+  filename = None
+  diff = []
+  for line in data.splitlines(True):
+    new_filename = None
+    if line.startswith('Index:'):
+      unused, new_filename = line.split(':', 1)
+      new_filename = new_filename.strip()
+    elif line.startswith('Property changes on:'):
+      unused, temp_filename = line.split(':', 1)
+      # When a file is modified, paths use '/' between directories, however
+      # when a property is modified '\' is used on Windows.  Make them the same
+      # otherwise the file shows up twice.
+      temp_filename = temp_filename.strip().replace('\\', '/')
+      if temp_filename != filename:
+        # File has property changes but no modifications, create a new diff.
+        new_filename = temp_filename
+    if new_filename:
+      if filename and diff:
+        patches.append((filename, ''.join(diff)))
+      filename = new_filename
+      diff = [line]
+      continue
+    if diff is not None:
+      diff.append(line)
+  if filename and diff:
+    patches.append((filename, ''.join(diff)))
+  return patches
+
+
+def UploadSeparatePatches(issue, rpc_server, patchset, data, options):
+  """Uploads a separate patch for each file in the diff output.
+
+  Returns a list of [patch_key, filename] for each file.
+  """
+  def UploadFile(filename, data):
+    form_fields = [("filename", filename)]
+    if not options.download_base:
+      form_fields.append(("content_upload", "1"))
+    files = [("data", "data.diff", data)]
+    ctype, body = EncodeMultipartFormData(form_fields, files)
+    url = "/%d/upload_patch/%d" % (int(issue), int(patchset))
+
+    try:
+      response_body = rpc_server.Send(url, body, content_type=ctype)
+    except urllib2.HTTPError as e:
+      response_body = ("Failed to upload patch for %s. Got %d status code." %
+          (filename, e.code))
+
+    lines = response_body.splitlines()
+    if not lines or lines[0] != "OK":
+      StatusUpdate("  --> %s" % response_body)
+      sys.exit(1)
+    return ("Uploaded patch for " + filename, [lines[1], filename])
+
+  threads = []
+  thread_pool = ThreadPool(options.num_upload_threads)
+
+  patches = SplitPatch(data)
+  rv = []
+  for patch in patches:
+    if len(patch[1]) > MAX_UPLOAD_SIZE:
+      print("Not uploading the patch for %s because the file is too large." %
+            (patch[0],))
+      continue
+
+    filename = patch[0]
+    data = patch[1]
+
+    t = thread_pool.apply_async(UploadFile, args=(filename, data))
+    threads.append(t)
+
+  for t in threads:
+    result = t.get(timeout=UPLOAD_TIMEOUT)
+    print(result[0])
+    rv.append(result[1])
+
+  return rv
+
+
+def GuessVCSName(options):
+  """Helper to guess the version control system.
+
+  This examines the current directory, guesses which VersionControlSystem
+  we're using, and returns an string indicating which VCS is detected.
+
+  Returns:
+    A pair (vcs, output).  vcs is a string indicating which VCS was detected
+    and is one of VCS_GIT, VCS_MERCURIAL, VCS_SUBVERSION, VCS_PERFORCE,
+    VCS_CVS, or VCS_UNKNOWN.
+    Since local perforce repositories can't be easily detected, this method
+    will only guess VCS_PERFORCE if any perforce options have been specified.
+    output is a string containing any interesting output from the vcs
+    detection routine, or None if there is nothing interesting.
+  """
+  for attribute, value in options.__dict__.iteritems():
+    if attribute.startswith("p4") and value != None:
+      return (VCS_PERFORCE, None)
+
+  def RunDetectCommand(vcs_type, command):
+    """Helper to detect VCS by executing command.
+
+    Returns:
+       A pair (vcs, output) or None. Throws exception on error.
+    """
+    try:
+      out, returncode = RunShellWithReturnCode(command)
+      if returncode == 0:
+        return (vcs_type, out.strip())
+    except OSError as e:
+      if e.errno != errno.ENOENT:  # command not found code
+        raise
+    except ValueError as e:
+      # Workaround for https://bugs.python.org/issue26083
+      if e.message != "insecure string pickle":
+        raise
+
+  # Mercurial has a command to get the base directory of a repository
+  # Try running it, but don't die if we don't have hg installed.
+  # NOTE: we try Mercurial first as it can sit on top of an SVN working copy.
+  res = RunDetectCommand(VCS_MERCURIAL, ["hg", "root"])
+  if res != None:
+    return res
+
+  # Subversion from 1.7 has a single centralized .svn folder
+  # ( see http://subversion.apache.org/docs/release-notes/1.7.html#wc-ng )
+  # That's why we use 'svn info' instead of checking for .svn dir
+  res = RunDetectCommand(VCS_SUBVERSION, ["svn", "info"])
+  if res != None:
+    return res
+
+  # Git has a command to test if you're in a git tree.
+  # Try running it, but don't die if we don't have git installed.
+  res = RunDetectCommand(VCS_GIT, ["git", "rev-parse",
+                                   "--is-inside-work-tree"])
+  if res != None:
+    return res
+
+  # detect CVS repos use `cvs status && $? == 0` rules
+  res = RunDetectCommand(VCS_CVS, ["cvs", "status"])
+  if res != None:
+    return res
+
+  return (VCS_UNKNOWN, None)
+
+
+def GuessVCS(options):
+  """Helper to guess the version control system.
+
+  This verifies any user-specified VersionControlSystem (by command line
+  or environment variable).  If the user didn't specify one, this examines
+  the current directory, guesses which VersionControlSystem we're using,
+  and returns an instance of the appropriate class.  Exit with an error
+  if we can't figure it out.
+
+  Returns:
+    A VersionControlSystem instance. Exits if the VCS can't be guessed.
+  """
+  vcs = options.vcs
+  if not vcs:
+    vcs = os.environ.get("CODEREVIEW_VCS")
+  if vcs:
+    v = VCS_ABBREVIATIONS.get(vcs.lower())
+    if v is None:
+      ErrorExit("Unknown version control system %r specified." % vcs)
+    (vcs, extra_output) = (v, None)
+  else:
+    (vcs, extra_output) = GuessVCSName(options)
+
+  if vcs == VCS_MERCURIAL:
+    if extra_output is None:
+      extra_output = RunShell(["hg", "root"]).strip()
+    return MercurialVCS(options, extra_output)
+  elif vcs == VCS_SUBVERSION:
+    return SubversionVCS(options)
+  elif vcs == VCS_PERFORCE:
+    return PerforceVCS(options)
+  elif vcs == VCS_GIT:
+    return GitVCS(options)
+  elif vcs == VCS_CVS:
+    return CVSVCS(options)
+
+  ErrorExit(("Could not guess version control system. "
+             "Are you in a working copy directory?"))
+
+
+def CheckReviewer(reviewer):
+  """Validate a reviewer -- either a nickname or an email addres.
+
+  Args:
+    reviewer: A nickname or an email address.
+
+  Calls ErrorExit() if it is an invalid email address.
+  """
+  if "@" not in reviewer:
+    return  # Assume nickname
+  parts = reviewer.split("@")
+  if len(parts) > 2:
+    ErrorExit("Invalid email address: %r" % reviewer)
+  assert len(parts) == 2
+  if "." not in parts[1]:
+    ErrorExit("Invalid email address: %r" % reviewer)
+
+
+def LoadSubversionAutoProperties():
+  """Returns the content of [auto-props] section of Subversion's config file as
+  a dictionary.
+
+  Returns:
+    A dictionary whose key-value pair corresponds the [auto-props] section's
+      key-value pair.
+    In following cases, returns empty dictionary:
+      - config file doesn't exist, or
+      - 'enable-auto-props' is not set to 'true-like-value' in [miscellany].
+  """
+  if os.name == 'nt':
+    subversion_config = os.environ.get("APPDATA") + "\\Subversion\\config"
+  else:
+    subversion_config = os.path.expanduser("~/.subversion/config")
+  if not os.path.exists(subversion_config):
+    return {}
+  config = configparser.ConfigParser()
+  config.read(subversion_config)
+  if (config.has_section("miscellany") and
+      config.has_option("miscellany", "enable-auto-props") and
+      config.getboolean("miscellany", "enable-auto-props") and
+      config.has_section("auto-props")):
+    props = {}
+    for file_pattern in config.options("auto-props"):
+      props[file_pattern] = ParseSubversionPropertyValues(
+        config.get("auto-props", file_pattern))
+    return props
+  else:
+    return {}
+
+def ParseSubversionPropertyValues(props):
+  """Parse the given property value which comes from [auto-props] section and
+  returns a list whose element is a (svn_prop_key, svn_prop_value) pair.
+
+  See the following doctest for example.
+
+  >>> ParseSubversionPropertyValues('svn:eol-style=LF')
+  [('svn:eol-style', 'LF')]
+  >>> ParseSubversionPropertyValues('svn:mime-type=image/jpeg')
+  [('svn:mime-type', 'image/jpeg')]
+  >>> ParseSubversionPropertyValues('svn:eol-style=LF;svn:executable')
+  [('svn:eol-style', 'LF'), ('svn:executable', '*')]
+  """
+  key_value_pairs = []
+  for prop in props.split(";"):
+    key_value = prop.split("=")
+    assert len(key_value) <= 2
+    if len(key_value) == 1:
+      # If value is not given, use '*' as a Subversion's convention.
+      key_value_pairs.append((key_value[0], "*"))
+    else:
+      key_value_pairs.append((key_value[0], key_value[1]))
+  return key_value_pairs
+
+
+def GetSubversionPropertyChanges(filename):
+  """Return a Subversion's 'Property changes on ...' string, which is used in
+  the patch file.
+
+  Args:
+    filename: filename whose property might be set by [auto-props] config.
+
+  Returns:
+    A string like 'Property changes on |filename| ...' if given |filename|
+      matches any entries in [auto-props] section. None, otherwise.
+  """
+  global svn_auto_props_map
+  if svn_auto_props_map is None:
+    svn_auto_props_map = LoadSubversionAutoProperties()
+
+  all_props = []
+  for file_pattern, props in svn_auto_props_map.items():
+    if fnmatch.fnmatch(filename, file_pattern):
+      all_props.extend(props)
+  if all_props:
+    return FormatSubversionPropertyChanges(filename, all_props)
+  return None
+
+
+def FormatSubversionPropertyChanges(filename, props):
+  """Returns Subversion's 'Property changes on ...' strings using given filename
+  and properties.
+
+  Args:
+    filename: filename
+    props: A list whose element is a (svn_prop_key, svn_prop_value) pair.
+
+  Returns:
+    A string which can be used in the patch file for Subversion.
+
+  See the following doctest for example.
+
+  >>> print FormatSubversionPropertyChanges('foo.cc', [('svn:eol-style', 'LF')])
+  Property changes on: foo.cc
+  ___________________________________________________________________
+  Added: svn:eol-style
+     + LF
+  <BLANKLINE>
+  """
+  prop_changes_lines = [
+    "Property changes on: %s" % filename,
+    "___________________________________________________________________"]
+  for key, value in props:
+    prop_changes_lines.append("Added: " + key)
+    prop_changes_lines.append("   + " + value)
+  return "\n".join(prop_changes_lines) + "\n"
+
+
+def RealMain(argv, data=None):
+  """The real main function.
+
+  Args:
+    argv: Command line arguments.
+    data: Diff contents. If None (default) the diff is generated by
+      the VersionControlSystem implementation returned by GuessVCS().
+
+  Returns:
+    A 2-tuple (issue id, patchset id).
+    The patchset id is None if the base files are not uploaded by this
+    script (applies only to SVN checkouts).
+  """
+  options, args = parser.parse_args(argv[1:])
+  if options.help:
+    if options.verbose < 2:
+      # hide Perforce options
+      parser.epilog = (
+        "Use '--help -v' to show additional Perforce options. "
+        "For more help, see "
+        "http://code.google.com/p/rietveld/wiki/CodeReviewHelp"
+        )
+      parser.option_groups.remove(parser.get_option_group('--p4_port'))
+    parser.print_help()
+    sys.exit(0)
+
+  global verbosity
+  verbosity = options.verbose
+  if verbosity >= 3:
+    LOGGER.setLevel(logging.DEBUG)
+  elif verbosity >= 2:
+    LOGGER.setLevel(logging.INFO)
+
+  vcs = GuessVCS(options)
+
+  if options.download_base:
+    options.download_base = True
+    LOGGER.info("Enabled upload of base file")
+  if not options.assume_yes:
+    vcs.CheckForUnknownFiles()
+  if data is None:
+    data = vcs.GenerateDiff(args)
+  data = vcs.PostProcessDiff(data)
+  if options.print_diffs:
+    print("Rietveld diff start:*****")
+    print(data)
+    print("Rietveld diff end:*****")
+  files = vcs.GetBaseFiles(data)
+  if verbosity >= 1:
+    print("Upload server:", options.server, "(change with -s/--server)")
+
+  auth_config = auth.extract_auth_config_from_options(options)
+  rpc_server = GetRpcServer(options.server, auth_config, options.email)
+  form_fields = []
+
+  repo_guid = vcs.GetGUID()
+  if repo_guid:
+    form_fields.append(("repo_guid", repo_guid))
+  if options.issue:
+    form_fields.append(("issue", str(options.issue)))
+  if options.email:
+    form_fields.append(("user", options.email))
+  if options.reviewers:
+    for reviewer in options.reviewers.split(','):
+      CheckReviewer(reviewer)
+    form_fields.append(("reviewers", options.reviewers))
+  if options.cc:
+    for cc in options.cc.split(','):
+      CheckReviewer(cc)
+    form_fields.append(("cc", options.cc))
+  if options.project:
+    form_fields.append(("project", options.project))
+  if options.target_ref:
+    form_fields.append(("target_ref", options.target_ref))
+  if options.cq_dry_run:
+    form_fields.append(("cq_dry_run", "1"))
+    form_fields.append(("commit", "1"))
+  if options.depends_on_patchset:
+    form_fields.append(("depends_on_patchset", options.depends_on_patchset))
+
+  # Process --message, --title and --file.
+  message = options.message or ""
+  explicit_title = options.title is not None
+  title = options.title or ""
+  if options.file:
+    if options.message:
+      ErrorExit("Can't specify both message and message file options")
+    file = open(options.file, 'r')
+    message = file.read()
+    file.close()
+  title = title or message.split('\n', 1)[0].strip()
+  if not title and not explicit_title:
+    if options.issue:
+      prompt = "Title describing this patch set"
+    else:
+      prompt = "New issue subject"
+    title_default = vcs.GetMostRecentCommitSummary()
+    if title_default:
+      prompt += " [%s]" % title_default
+    title = raw_input(prompt + ": ").strip() or title_default
+  if not title and not options.issue:
+    ErrorExit("A non-empty title is required for a new issue")
+  # For existing issues, it's fine to give a patchset an empty name. Rietveld
+  # doesn't accept that so use a whitespace.
+  title = title or " "
+  if len(title) > 100:
+    title = title[:99] + '…'
+  if title and not options.issue:
+    message = message or title
+
+  form_fields.append(("subject", title))
+  # If it's a new issue send message as description. Otherwise a new
+  # message is created below on upload_complete.
+  if message and not options.issue:
+    form_fields.append(("description", message))
+
+  # Send a hash of all the base file so the server can determine if a copy
+  # already exists in an earlier patchset.
+  base_hashes = ""
+  for file, info in files.iteritems():
+    if not info[0] is None:
+      checksum = md5(info[0]).hexdigest()
+      if base_hashes:
+        base_hashes += "|"
+      base_hashes += checksum + ":" + file
+  form_fields.append(("base_hashes", base_hashes))
+  if options.private:
+    if options.issue:
+      print("Warning: Private flag ignored when updating an existing issue.")
+    else:
+      form_fields.append(("private", "1"))
+  if options.send_patch:
+    options.send_mail = True
+  if not options.download_base:
+    form_fields.append(("content_upload", "1"))
+  if len(data) > MAX_UPLOAD_SIZE:
+    print("Patch is large, so uploading file patches separately.")
+    uploaded_diff_file = []
+    form_fields.append(("separate_patches", "1"))
+  else:
+    uploaded_diff_file = [("data", "data.diff", data)]
+  ctype, body = EncodeMultipartFormData(form_fields, uploaded_diff_file)
+  response_body = rpc_server.Send("/upload", body, content_type=ctype)
+  issue, patchset = None, None
+  if not options.download_base or not uploaded_diff_file:
+    lines = response_body.splitlines()
+    if len(lines) >= 2:
+      # lines[0] is "Issue (created|updated): <url>".
+      issue = lines[0][lines[0].rfind("/")+1:]
+      # lines[1] is just patchset number.
+      patchset = lines[1].strip()
+      msg = '%s (patchset: %s)' % (lines[0], patchset)
+      patches = [x.split(" ", 1) for x in lines[2:]]
+    else:
+      msg = response_body
+  else:
+    msg = response_body
+  StatusUpdate(msg)
+  if not response_body.startswith("Issue created.") and \
+  not response_body.startswith("Issue updated."):
+    sys.exit(0)
+  assert issue
+
+  if not uploaded_diff_file:
+    result = UploadSeparatePatches(issue, rpc_server, patchset, data, options)
+    if not options.download_base:
+      patches = result
+
+  if not options.download_base:
+    vcs.UploadBaseFiles(issue, rpc_server, patches, patchset, options, files)
+
+  payload = {}  # payload for final request
+  if options.send_mail:
+    payload["send_mail"] = "yes"
+    if options.send_patch:
+      payload["attach_patch"] = "yes"
+  if options.issue and message:
+    payload["message"] = message
+  payload = urllib.urlencode(payload)
+  rpc_server.Send("/" + issue + "/upload_complete/" + (patchset or ""),
+                  payload=payload)
+  return issue, patchset
+
+
+def main():
+  try:
+    logging.basicConfig(format=("%(asctime).19s %(levelname)s %(filename)s:"
+                                "%(lineno)s %(message)s "))
+    os.environ['LC_ALL'] = 'C'
+    RealMain(sys.argv)
+  except KeyboardInterrupt:
+    print()
+    StatusUpdate("Interrupted.")
+    sys.exit(1)
+  except auth.AuthenticationError as e:
+    print(e, file=sys.stderr)
+    sys.exit(1)
+
+
+if __name__ == "__main__":
+  main()