config/MozZipFile.py
author Eric Rahm <erahm@mozilla.com>
Thu, 10 Nov 2016 12:47:23 -0800
changeset 348770 e27050b02d69b88e19e0dcd151916f78259f9bb1
parent 159110 4a2c4921ff7cabb2ca41bdf30b0f58b0a9e16c67
permissions -rw-r--r--
Bug 1313488 - Part 1: Convert XPCOM test TestDeadlockDetector to a gtest. r=froydnj This converts TestDeadlockDetector to a gtest. The logic for spawning off subprocesses is replaced with gtest's built-in death tests. On linux this will clone() the process and assert that the child process generates the appropriate assertion message. On OSX it will use fork(). In theory this should work on Windows as well buy spawning a new process but this test currently disabled there. MozReview-Commit-ID: 9Sl0hHBVGT3

# 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 http://mozilla.org/MPL/2.0/.

import os
import time
import zipfile

from mozbuild.util import lock_file


class ZipFile(zipfile.ZipFile):
  """ Class with methods to open, read, write, close, list zip files.

  Subclassing zipfile.ZipFile to allow for overwriting of existing
  entries, though only for writestr, not for write.
  """
  def __init__(self, file, mode="r", compression=zipfile.ZIP_STORED,
               lock = False):
    if lock:
      assert isinstance(file, basestring)
      self.lockfile = lock_file(file + '.lck')
    else:
      self.lockfile = None

    if mode == 'a' and lock:
      # appending to a file which doesn't exist fails, but we can't check
      # existence util we hold the lock
      if (not os.path.isfile(file)) or os.path.getsize(file) == 0:
        mode = 'w'

    zipfile.ZipFile.__init__(self, file, mode, compression)
    self._remove = []
    self.end = self.fp.tell()
    self.debug = 0

  def writestr(self, zinfo_or_arcname, bytes):
    """Write contents into the archive.

    The contents is the argument 'bytes',  'zinfo_or_arcname' is either
    a ZipInfo instance or the name of the file in the archive.
    This method is overloaded to allow overwriting existing entries.
    """
    if not isinstance(zinfo_or_arcname, zipfile.ZipInfo):
      zinfo = zipfile.ZipInfo(filename=zinfo_or_arcname,
                              date_time=time.localtime(time.time()))
      zinfo.compress_type = self.compression
      # Add some standard UNIX file access permissions (-rw-r--r--).
      zinfo.external_attr = (0x81a4 & 0xFFFF) << 16L
    else:
      zinfo = zinfo_or_arcname

    # Now to the point why we overwrote this in the first place,
    # remember the entry numbers if we already had this entry.
    # Optimizations:
    # If the entry to overwrite is the last one, just reuse that.
    # If we store uncompressed and the new content has the same size
    # as the old, reuse the existing entry.

    doSeek = False # store if we need to seek to the eof after overwriting
    if self.NameToInfo.has_key(zinfo.filename):
      # Find the last ZipInfo with our name.
      # Last, because that's catching multiple overwrites
      i = len(self.filelist)
      while i > 0:
        i -= 1
        if self.filelist[i].filename == zinfo.filename:
          break
      zi = self.filelist[i]
      if ((zinfo.compress_type == zipfile.ZIP_STORED
           and zi.compress_size == len(bytes))
          or (i + 1) == len(self.filelist)):
        # make sure we're allowed to write, otherwise done by writestr below
        self._writecheck(zi)
        # overwrite existing entry
        self.fp.seek(zi.header_offset)
        if (i + 1) == len(self.filelist):
          # this is the last item in the file, just truncate
          self.fp.truncate()
        else:
          # we need to move to the end of the file afterwards again
          doSeek = True
        # unhook the current zipinfo, the writestr of our superclass
        # will add a new one
        self.filelist.pop(i)
        self.NameToInfo.pop(zinfo.filename)
      else:
        # Couldn't optimize, sadly, just remember the old entry for removal
        self._remove.append(self.filelist.pop(i))
    zipfile.ZipFile.writestr(self, zinfo, bytes)
    self.filelist.sort(lambda l, r: cmp(l.header_offset, r.header_offset))
    if doSeek:
      self.fp.seek(self.end)
    self.end = self.fp.tell()

  def close(self):
    """Close the file, and for mode "w" and "a" write the ending
    records.

    Overwritten to compact overwritten entries.
    """
    if not self._remove:
      # we don't have anything special to do, let's just call base
      r = zipfile.ZipFile.close(self)
      self.lockfile = None
      return r

    if self.fp.mode != 'r+b':
      # adjust file mode if we originally just wrote, now we rewrite
      self.fp.close()
      self.fp = open(self.filename, 'r+b')
    all = map(lambda zi: (zi, True), self.filelist) + \
        map(lambda zi: (zi, False), self._remove)
    all.sort(lambda l, r: cmp(l[0].header_offset, r[0].header_offset))
    # empty _remove for multiple closes
    self._remove = []

    lengths = [all[i+1][0].header_offset - all[i][0].header_offset
               for i in xrange(len(all)-1)]
    lengths.append(self.end - all[-1][0].header_offset)
    to_pos = 0
    for (zi, keep), length in zip(all, lengths):
      if not keep:
        continue
      oldoff = zi.header_offset
      # python <= 2.4 has file_offset
      if hasattr(zi, 'file_offset'):
        zi.file_offset = zi.file_offset + to_pos - oldoff
      zi.header_offset = to_pos
      self.fp.seek(oldoff)
      content = self.fp.read(length)
      self.fp.seek(to_pos)
      self.fp.write(content)
      to_pos += length
    self.fp.truncate()
    zipfile.ZipFile.close(self)
    self.lockfile = None