CellHeader.py - mozsearch

Enable keyboard shortcuts

# 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 gdb

def get_header_ptr(value, ptr_t):

    # Return the pointer stored in Cell::header_ for subclasses of

    # TenuredCellWithNonGCPointer and CellWithTenuredGCPointer.

    return value["header_"]["value_"].cast(ptr_t)

def get_header_length_and_flags(value, cache):

    # Return the length and flags values for subclasses of

    # CellWithLengthAndFlags.

    flags = value["header_"]["value_"].cast(cache.uintptr_t)

    try:

        length = value["length_"]

    except gdb.error:

        # If we couldn't fetch the length directly, it must be stored

        # within `flags`.

        length = flags >> 32

        flags = flags % 2**32

    return length, flags