| Message ID | 20200604174135.11042-8-vsementsov@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iotests: Dump QCOW2 dirty bitmaps metadata | expand |
Two more int types in the comment?
Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
05.06.2020 15:29, Andrey Shinkevich wrote: > Two more int types in the comment? > > Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> > > ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ > *From:* Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > *Sent:* Thursday, June 4, 2020 8:41 PM > *To:* qemu-block@nongnu.org <qemu-block@nongnu.org> > *Cc:* qemu-devel@nongnu.org <qemu-devel@nongnu.org>; mreitz@redhat.com <mreitz@redhat.com>; kwolf@redhat.com <kwolf@redhat.com>; eblake@redhat.com <eblake@redhat.com>; Denis Lunev <den@virtuozzo.com>; Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>; Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> > *Subject:* [PATCH v4 07/12] qcow2_format.py: separate generic functionality of structure classes > We are going to introduce more Qcow2 structure types, defined like > QcowHeader. Move generic functionality into base class to be reused for > further structure classes. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > tests/qemu-iotests/qcow2_format.py | 93 +++++++++++++++++++----------- > 1 file changed, 58 insertions(+), 35 deletions(-) > > diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py > index 1fd9473b7f..d71f578377 100644 > --- a/tests/qemu-iotests/qcow2_format.py > +++ b/tests/qemu-iotests/qcow2_format.py > @@ -2,6 +2,62 @@ import struct > > + > +class Qcow2Struct(metaclass=Qcow2StructMeta): > + > + """Qcow2Struct: base class for qcow2 data structures > + > + Successors should define fields class variable, which is: list of tuples, > + each of three elements: > + - c-type (one of 'u32', 'u64') > > u8, u16 ? yes
diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py index 1fd9473b7f..d71f578377 100644 --- a/tests/qemu-iotests/qcow2_format.py +++ b/tests/qemu-iotests/qcow2_format.py @@ -2,6 +2,62 @@ import struct import string +class Qcow2StructMeta(type): + + # Mapping from c types to python struct format + ctypes = { + 'u8': 'B', + 'u16': 'H', + 'u32': 'I', + 'u64': 'Q' + } + + def __init__(self, name, bases, attrs): + if 'fields' in attrs: + self.fmt = '>' + ''.join(self.ctypes[f[0]] for f in self.fields) + + +class Qcow2Struct(metaclass=Qcow2StructMeta): + + """Qcow2Struct: base class for qcow2 data structures + + Successors should define fields class variable, which is: list of tuples, + each of three elements: + - c-type (one of 'u32', 'u64') + - format (format_spec to use with .format() when dump or 'mask' to dump + bitmasks) + - field name + """ + + def __init__(self, fd=None, offset=None, data=None): + if data is None: + assert fd is not None + buf_size = struct.calcsize(self.fmt) + if offset is not None: + fd.seek(offset) + data = fd.read(buf_size) + else: + assert fd is None and offset is None + + values = struct.unpack(self.fmt, data) + self.__dict__ = dict((field[2], values[i]) + for i, field in enumerate(self.fields)) + + 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: + value_str = f[1].format(value) + + print('{:<25} {}'.format(f[2], value_str)) + + class QcowHeaderExtension: def __init__(self, magic, length, data): @@ -18,16 +74,7 @@ class QcowHeaderExtension: return QcowHeaderExtension(magic, len(data), data) -# Mapping from c types to python struct format -ctypes = { - 'u8': 'B', - 'u16': 'H', - 'u32': 'I', - 'u64': 'Q' -} - - -class QcowHeader: +class QcowHeader(Qcow2Struct): fields = ( # Version 2 header fields @@ -53,18 +100,8 @@ class QcowHeader: ('u32', '{}', 'header_length'), ) - fmt = '>' + ''.join(ctypes[f[0]] for f in fields) - def __init__(self, fd): - - buf_size = struct.calcsize(QcowHeader.fmt) - - fd.seek(0) - buf = fd.read(buf_size) - - header = struct.unpack(QcowHeader.fmt, buf) - self.__dict__ = dict((field[2], header[i]) - for i, field in enumerate(QcowHeader.fields)) + super().__init__(fd=fd, offset=0) self.set_defaults() self.cluster_size = 1 << self.cluster_bits @@ -132,20 +169,6 @@ class QcowHeader: buf = buf[0:header_bytes-1] fd.write(buf) - def dump(self): - for f in QcowHeader.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: - value_str = f[1].format(value) - - print(f'{f[2]:<25} {value_str}') - def dump_extensions(self): for ex in self.extensions:
We are going to introduce more Qcow2 structure types, defined like QcowHeader. Move generic functionality into base class to be reused for further structure classes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- tests/qemu-iotests/qcow2_format.py | 93 +++++++++++++++++++----------- 1 file changed, 58 insertions(+), 35 deletions(-)