예제 #1
0
    def is_valid_stream(self, sha, use_crc=False):
        """
        Verify that the stream at the given sha is valid.

        :param use_crc: if True, the index' crc is run over the compressed stream of
            the object, which is much faster than checking the sha1. It is also
            more prone to unnoticed corruption or manipulation.
        :param sha: 20 byte sha1 of the object whose stream to verify
            whether the compressed stream of the object is valid. If it is
            a delta, this only verifies that the delta's data is valid, not the
            data of the actual undeltified object, as it depends on more than
            just this stream.
            If False, the object will be decompressed and the sha generated. It must
            match the given sha

        :return: True if the stream is valid
        :raise UnsupportedOperation: If the index is version 1 only
        :raise BadObject: sha was not found"""
        if use_crc:
            if self._index.version() < 2:
                raise UnsupportedOperation(
                    "Version 1 indices do not contain crc's, verify by sha instead"
                )
            # END handle index version

            index = self._sha_to_index(sha)
            offset = self._index.offset(index)
            next_offset = self._offset_map[offset]
            crc_value = self._index.crc(index)

            # create the current crc value, on the compressed object data
            # Read it in chunks, without copying the data
            crc_update = zlib.crc32
            pack_data = self._pack.data()
            cur_pos = offset
            this_crc_value = 0
            while cur_pos < next_offset:
                rbound = min(cur_pos + chunk_size, next_offset)
                size = rbound - cur_pos
                this_crc_value = crc_update(buffer(pack_data, cur_pos, size),
                                            this_crc_value)
                cur_pos += size
            # END window size loop

            # crc returns signed 32 bit numbers, the AND op forces it into unsigned
            # mode ... wow, sneaky, from dulwich.
            return (this_crc_value & 0xffffffff) == crc_value
        else:
            shawriter = Sha1Writer()
            stream = self._object(sha, as_stream=True)
            # write a loose object, which is the basis for the sha
            write_object(stream.type, stream.size, stream.read,
                         shawriter.write)

            assert shawriter.sha(as_hex=False) == sha
            return shawriter.sha(as_hex=False) == sha
        # END handle crc/sha verification
        return True
예제 #2
0
파일: pack.py 프로젝트: yarikoptic/gitdb
    def is_valid_stream(self, sha, use_crc=False):
        """
        Verify that the stream at the given sha is valid.

        :param use_crc: if True, the index' crc is run over the compressed stream of
            the object, which is much faster than checking the sha1. It is also
            more prone to unnoticed corruption or manipulation.
        :param sha: 20 byte sha1 of the object whose stream to verify
            whether the compressed stream of the object is valid. If it is
            a delta, this only verifies that the delta's data is valid, not the
            data of the actual undeltified object, as it depends on more than
            just this stream.
            If False, the object will be decompressed and the sha generated. It must
            match the given sha

        :return: True if the stream is valid
        :raise UnsupportedOperation: If the index is version 1 only
        :raise BadObject: sha was not found"""
        if use_crc:
            if self._index.version() < 2:
                raise UnsupportedOperation("Version 1 indices do not contain crc's, verify by sha instead")
            # END handle index version

            index = self._sha_to_index(sha)
            offset = self._index.offset(index)
            next_offset = self._offset_map[offset]
            crc_value = self._index.crc(index)

            # create the current crc value, on the compressed object data
            # Read it in chunks, without copying the data
            crc_update = zlib.crc32
            pack_data = self._pack.data()
            cur_pos = offset
            this_crc_value = 0
            while cur_pos < next_offset:
                rbound = min(cur_pos + chunk_size, next_offset)
                size = rbound - cur_pos
                this_crc_value = crc_update(buffer(pack_data, cur_pos, size), this_crc_value)
                cur_pos += size
            # END window size loop

            # crc returns signed 32 bit numbers, the AND op forces it into unsigned
            # mode ... wow, sneaky, from dulwich.
            return (this_crc_value & 0xffffffff) == crc_value
        else:
            shawriter = Sha1Writer()
            stream = self._object(sha, as_stream=True)
            # write a loose object, which is the basis for the sha
            write_object(stream.type, stream.size, stream.read, shawriter.write)

            assert shawriter.sha(as_hex=False) == sha
            return shawriter.sha(as_hex=False) == sha
        # END handle crc/sha verification
        return True
예제 #3
0
    def store(self, istream):
        """note: The sha we produce will be hex by nature"""
        tmp_path = None
        writer = self.ostream()
        if writer is None:
            # open a tmp file to write the data to
            fd, tmp_path = tempfile.mkstemp(prefix="obj", dir=self._root_path)

            if istream.binsha is None:
                writer = FDCompressedSha1Writer(fd)
            else:
                writer = FDStream(fd)
            # END handle direct stream copies
        # END handle custom writer

        try:
            try:
                if istream.binsha is not None:
                    # copy as much as possible, the actual uncompressed item size might
                    # be smaller than the compressed version
                    stream_copy(istream.read, writer.write, MAXSIZE, self.stream_chunk_size)
                else:
                    # write object with header, we have to make a new one
                    write_object(
                        istream.type, istream.size, istream.read, writer.write, chunk_size=self.stream_chunk_size
                    )
                # END handle direct stream copies
            finally:
                if tmp_path:
                    writer.close()
            # END assure target stream is closed
        except:
            if tmp_path:
                os.remove(tmp_path)
            raise
        # END assure tmpfile removal on error

        hexsha = None
        if istream.binsha:
            hexsha = istream.hexsha
        else:
            hexsha = writer.sha(as_hex=True)
        # END handle sha

        if tmp_path:
            obj_path = self.db_path(self.object_path(hexsha))
            obj_dir = dirname(obj_path)
            if not isdir(obj_dir):
                mkdir(obj_dir)
            # END handle destination directory
            # rename onto existing doesn't work on windows
            if os.name == "nt":
                if isfile(obj_path):
                    remove(tmp_path)
                else:
                    rename(tmp_path, obj_path)
                # end rename only if needed
            else:
                rename(tmp_path, obj_path)
            # END handle win32

            # make sure its readable for all ! It started out as rw-- tmp file
            # but needs to be rwrr
            chmod(obj_path, self.new_objects_mode)
        # END handle dry_run

        istream.binsha = hex_to_bin(hexsha)
        return istream
예제 #4
0
    def store(self, istream):
        """note: The sha we produce will be hex by nature"""
        tmp_path = None
        writer = self.ostream()
        if writer is None:
            # open a tmp file to write the data to
            fd, tmp_path = tempfile.mkstemp(prefix='obj', dir=self._root_path)

            if istream.binsha is None:
                writer = FDCompressedSha1Writer(fd)
            else:
                writer = FDStream(fd)
            # END handle direct stream copies
        # END handle custom writer

        try:
            try:
                if istream.binsha is not None:
                    # copy as much as possible, the actual uncompressed item size might
                    # be smaller than the compressed version
                    stream_copy(istream.read, writer.write, sys.maxint,
                                self.stream_chunk_size)
                else:
                    # write object with header, we have to make a new one
                    write_object(istream.type,
                                 istream.size,
                                 istream.read,
                                 writer.write,
                                 chunk_size=self.stream_chunk_size)
                # END handle direct stream copies
            finally:
                if tmp_path:
                    writer.close()
            # END assure target stream is closed
        except:
            if tmp_path:
                os.remove(tmp_path)
            raise
        # END assure tmpfile removal on error

        hexsha = None
        if istream.binsha:
            hexsha = istream.hexsha
        else:
            hexsha = writer.sha(as_hex=True)
        # END handle sha

        if tmp_path:
            obj_path = self.db_path(self.object_path(hexsha))
            obj_dir = dirname(obj_path)
            if not isdir(obj_dir):
                mkdir(obj_dir)
            # END handle destination directory
            # rename onto existing doesn't work on windows
            if os.name == 'nt' and isfile(obj_path):
                remove(obj_path)
            # END handle win322
            rename(tmp_path, obj_path)

            # make sure its readable for all ! It started out as rw-- tmp file
            # but needs to be rwrr
            chmod(obj_path, self.new_objects_mode)
        # END handle dry_run

        istream.binsha = hex_to_bin(hexsha)
        return istream