Commit 5432a0db authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
Browse files

qcow2_format.py: use strings to specify c-type of struct fields 



We are going to move field-parsing to super-class, this will be simpler
with simple string specifiers instead of variables.

For some reason, python doesn't allow the definition of ctypes variable
in the class alongside fields: it would not be available then for use
by the 'for' operator. Don't worry: ctypes will be moved to metaclass
soon.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarAndrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Message-Id: <20200606081806.23897-8-vsementsov@virtuozzo.com>
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent 621ca498

tests/qemu-iotests/qcow2_format.py

+28 −22
Original line number Diff line number Diff line
@@ -34,36 +34,42 @@ class QcowHeaderExtension: 
        return QcowHeaderExtension(magic, len(data), data)





class QcowHeader:

# Mapping from c types to python struct format

ctypes = {

    'u8': 'B',

    'u16': 'H',

    'u32': 'I',

    'u64': 'Q'

}





    uint32_t = 'I'

    uint64_t = 'Q'

class QcowHeader:



    fields = (

        # Version 2 header fields

        (uint32_t, '{:#x}', 'magic'),

        (uint32_t, '{}', 'version'),

        (uint64_t, '{:#x}', 'backing_file_offset'),

        (uint32_t, '{:#x}', 'backing_file_size'),

        (uint32_t, '{}', 'cluster_bits'),

        (uint64_t, '{}', 'size'),

        (uint32_t, '{}', 'crypt_method'),

        (uint32_t, '{}', 'l1_size'),

        (uint64_t, '{:#x}', 'l1_table_offset'),

        (uint64_t, '{:#x}', 'refcount_table_offset'),

        (uint32_t, '{}', 'refcount_table_clusters'),

        (uint32_t, '{}', 'nb_snapshots'),

        (uint64_t, '{:#x}', 'snapshot_offset'),

        ('u32', '{:#x}', 'magic'),

        ('u32', '{}', 'version'),

        ('u64', '{:#x}', 'backing_file_offset'),

        ('u32', '{:#x}', 'backing_file_size'),

        ('u32', '{}', 'cluster_bits'),

        ('u64', '{}', 'size'),

        ('u32', '{}', 'crypt_method'),

        ('u32', '{}', 'l1_size'),

        ('u64', '{:#x}', 'l1_table_offset'),

        ('u64', '{:#x}', 'refcount_table_offset'),

        ('u32', '{}', 'refcount_table_clusters'),

        ('u32', '{}', 'nb_snapshots'),

        ('u64', '{:#x}', 'snapshot_offset'),



        # Version 3 header fields

        (uint64_t, 'mask', 'incompatible_features'),

        (uint64_t, 'mask', 'compatible_features'),

        (uint64_t, 'mask', 'autoclear_features'),

        (uint32_t, '{}', 'refcount_order'),

        (uint32_t, '{}', 'header_length'),

        ('u64', 'mask', 'incompatible_features'),

        ('u64', 'mask', 'compatible_features'),

        ('u64', 'mask', 'autoclear_features'),

        ('u32', '{}', 'refcount_order'),

        ('u32', '{}', 'header_length'),

    )



    fmt = '>' + ''.join(field[0] for field in fields)

    fmt = '>' + ''.join(ctypes[f[0]] for f in fields)



    def __init__(self, fd):