author Andrew McCreight <>
Mon, 22 Apr 2019 16:34:51 +0000
changeset 470376 3073770e06f157040f4c64951b7e8425e1ad7bbe
parent 381787 76aceb596872aef0261a7771b7a9e07828db55a7
permissions -rwxr-xr-x
Bug 1535403 - Take indirection into account for the CC optimizations for the outer window wrapper. r=peterv Most wrapper cached C++ objects are held alive by their wrapper. The cycle collector takes advantage of this in many classes and ignores the C++ object if the wrapper is marked black. However, this is not true for the outer window's wrapper. Instead, the outer window's wrapper keeps the inner window alive. The inner window usually keeps its outer window alive, but not after it has been unlinked. For reasons I do not yet understand, the outer window's wrapper can be kept alive after the inner window it is a proxy for is unlinked. This patch fixes the cycle collector optimization for the outer window by only applying it if the outer window still has a weak reference to the inner window, which it will until the inner no longer holds the outer alive. This in turn fixes, or at least helps fix, window leaks seen intermittently when the lifetime of outer windows and docshells are tied together. The code comment is based on a review comment by peterv. Differential Revision:

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at

LIBFFI_DIRS = (('js/ctypes/libffi', 'libffi'),)
HG_EXCLUSIONS = ['.hg', '.hgignore', '.hgtags']


import os
import sys
import datetime
import shutil
import glob
from optparse import OptionParser
from subprocess import check_call

topsrcdir = os.path.dirname(__file__)
if topsrcdir == '':
    topsrcdir = '.'

def check_call_noisy(cmd, *args, **kwargs):
    print "Executing command:", cmd
    check_call(cmd, *args, **kwargs)

def do_hg_pull(dir, repository, hg):
    fulldir = os.path.join(topsrcdir, dir)
    # clone if the dir doesn't exist, pull if it does
    if not os.path.exists(fulldir):
        check_call_noisy([hg, 'clone', repository, fulldir])
        cmd = [hg, 'pull', '-u', '-R', fulldir]
        if repository is not None:
    check_call([hg, 'parent', '-R', fulldir,
                '--template=Updated to revision {node}.\n'])

def do_hg_replace(dir, repository, tag, exclusions, hg):
        Replace the contents of dir with the contents of repository, except for
        files matching exclusions.
    fulldir = os.path.join(topsrcdir, dir)
    if os.path.exists(fulldir):

    assert not os.path.exists(fulldir)
    check_call_noisy([hg, 'clone', '-u', tag, repository, fulldir])

    for thing in exclusions:
        for excluded in glob.iglob(os.path.join(fulldir, thing)):
            if os.path.isdir(excluded):

def do_cvs_export(modules, tag, cvsroot, cvs):
    """Check out a CVS directory without CVS metadata, using "export"
    modules is a list of directories to check out and the corresponding
    cvs module, e.g. (('js/ctypes/libffi', 'libffi'),)
    for module_tuple in modules:
        module = module_tuple[0]
        cvs_module = module_tuple[1]
        fullpath = os.path.join(topsrcdir, module)
        if os.path.exists(fullpath):
            print "Removing '%s'" % fullpath

        (parent, leaf) = os.path.split(module)
        print "CVS export begin: " + datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC")
        check_call_noisy([cvs, '-d', cvsroot,
                          'export', '-r', tag, '-d', leaf, cvs_module],
                         cwd=os.path.join(topsrcdir, parent))
        print "CVS export end: " + datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC")

def toggle_trailing_blank_line(depname):
  """If the trailing line is empty, then we'll delete it.
  Otherwise we'll add a blank line."""
  lines = open(depname, "r").readlines()
  if not lines:
      print >>sys.stderr, "unexpected short file"

  if not lines[-1].strip():
      # trailing line is blank, removing it
      open(depname, "wb").writelines(lines[:-1])
      # adding blank line
      open(depname, "ab").write("\n")

def get_trailing_blank_line_state(depname):
  lines = open(depname, "r").readlines()
  if not lines:
      print >>sys.stderr, "unexpected short file"
      return "no blank line"

  if not lines[-1].strip():
      return "has blank line"
      return "no blank line"

def update_nspr_or_nss(tag, depfile, destination, hgpath):
  destination = destination.rstrip('/')
  permanent_patch_dir = destination + '/patches'
  temporary_patch_dir = destination + '.patches'
  if os.path.exists(temporary_patch_dir):
    print "please clean up leftover directory " + temporary_patch_dir
  # protect patch directory from being removed by do_hg_replace
  if os.path.exists(permanent_patch_dir):
    shutil.move(permanent_patch_dir, temporary_patch_dir)
  # now update the destination
  print "reverting to HG version of %s to get its blank line state" % depfile
  check_call_noisy([options.hg, 'revert', depfile])
  old_state = get_trailing_blank_line_state(depfile)
  print "old state of %s is: %s" % (depfile, old_state)
  do_hg_replace(destination, hgpath, tag, HG_EXCLUSIONS, options.hg)
  new_state = get_trailing_blank_line_state(depfile)
  print "new state of %s is: %s" % (depfile, new_state)
  if old_state == new_state:
    print "toggling blank line in: ", depfile
  tag_file = destination + "/TAG-INFO"
  print >>file(tag_file, "w"), tag
  # move patch directory back to a subdirectory
  if os.path.exists(temporary_patch_dir):
    shutil.move(temporary_patch_dir, permanent_patch_dir)

def warn_if_patch_exists(path):
  # If the given patch directory exists and contains at least one file,
  # then print warning and wait for the user to acknowledge.
  if os.path.isdir(path) and os.listdir(path):
    print "========================================"
    print "WARNING: At least one patch file exists"
    print "in directory: " + path
    print "You must manually re-apply all patches"
    print "after this script has completed!"
    print "========================================"
    raw_input("Press Enter to continue...")

o = OptionParser(usage=" [options] update_nspr tagname | update_nss tagname | update_libffi tagname")
o.add_option("--skip-mozilla", dest="skip_mozilla",
             action="store_true", default=False,

o.add_option("--cvs", dest="cvs", default=os.environ.get('CVS', 'cvs'),
             help="The location of the cvs binary")
o.add_option("--cvsroot", dest="cvsroot",
             help="The CVSROOT for libffi (default : %s)" % CVSROOT_LIBFFI)
o.add_option("--hg", dest="hg", default=os.environ.get('HG', 'hg'),
             help="The location of the hg binary")
o.add_option("--repo", dest="repo",
             help="the repo to update from (default: upstream repo)")

    options, args = o.parse_args()
    action = args[0]
except IndexError:

if action in ('checkout', 'co'):
    print >>sys.stderr, "Warning: checkout is obsolete."
elif action in ('update_nspr'):
    tag, = args[1:]
    depfile = "nsprpub/config/prdepend.h"
    if not options.repo:
        options.repo = ''
    update_nspr_or_nss(tag, depfile, 'nsprpub', options.repo)
elif action in ('update_nss'):
    tag, = args[1:]
    depfile = "security/nss/coreconf/coreconf.dep"
    if not options.repo:
	    options.repo = ''
    update_nspr_or_nss(tag, depfile, 'security/nss', options.repo)
elif action in ('update_libffi'):
    tag, = args[1:]
    if not options.cvsroot:
        options.cvsroot = CVSROOT_LIBFFI
    do_cvs_export(LIBFFI_DIRS, tag, options.cvsroot, options.cvs)