Commit 860543f0 authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
Browse files

qcow2_format.py: add field-formatting class 



Allow formatter class in structure definition instead of hacking with
'mask'. This will simplify further introduction of new formatters.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarAndrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Message-Id: <20200606081806.23897-10-vsementsov@virtuozzo.com>
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent 0903e3b3

tests/qemu-iotests/qcow2_format.py

+25 −10
Original line number Diff line number Diff line
@@ -20,6 +20,25 @@ import struct 
import string





class Qcow2Field:



    def __init__(self, value):

        self.value = value



    def __str__(self):

        return str(self.value)





class Flags64(Qcow2Field):



    def __str__(self):

        bits = []

        for bit in range(64):

            if self.value & (1 << bit):

                bits.append(bit)

        return str(bits)





class Qcow2StructMeta(type):



    # Mapping from c types to python struct format
@@ -70,14 +89,10 @@ class Qcow2Struct(metaclass=Qcow2StructMeta): 
    def dump(self):

        for f in self.fields:

            value = self.__dict__[f[2]]

            if f[1] == 'mask':

                bits = []

                for bit in range(64):

                    if value & (1 << bit):

                        bits.append(bit)

                value_str = str(bits)

            else:

            if isinstance(f[1], str):

                value_str = f[1].format(value)

            else:

                value_str = str(f[1](value))



            print('{:<25} {}'.format(f[2], value_str))
@@ -117,9 +132,9 @@ class QcowHeader(Qcow2Struct): 
        ('u64', '{:#x}', 'snapshot_offset'),



        # Version 3 header fields

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

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

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

        ('u64', Flags64, 'incompatible_features'),

        ('u64', Flags64, 'compatible_features'),

        ('u64', Flags64, 'autoclear_features'),

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

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

    )