Re: [Qemu-devel] [PATCH 2/8] iotests/257: add EmulatedBitmap class

[John Snow <jsnow@redhat.com>]

On 7/10/19 11:47 AM, Max Reitz wrote:
> On 10.07.19 03:05, John Snow wrote:
>> Represent a bitmap with an object that we can mark and clear bits in.
>> This makes it easier to manage partial writes when we don't write a
>> full group's worth of patterns before an error.
>>
>> Signed-off-by: John Snow <jsnow@redhat.com>
>> ---
>>  tests/qemu-iotests/257 | 125 +++++++++++++++++++++++++----------------
>>  1 file changed, 76 insertions(+), 49 deletions(-)
>>
>> diff --git a/tests/qemu-iotests/257 b/tests/qemu-iotests/257
>> index f576a35a5c..2ff4aa8695 100755
>> --- a/tests/qemu-iotests/257
>> +++ b/tests/qemu-iotests/257
>> @@ -85,6 +85,60 @@ GROUPS = [
>>          Pattern('0xdd', 0x3fc0000)]), # New; leaving a gap to the right
>>  ]
>>  
>> +
>> +class EmulatedBitmap:
>> +    def __init__(self, granularity=GRANULARITY):
>> +        self._bits = set()
>> +        self.groups = set()
>> +        self.granularity = granularity
>> +
>> +    def dirty_bits(self, bits):
>> +        self._bits |= set(bits)
>> +
>> +    def dirty_group(self, n):
>> +        self.dirty_bits(GROUPS[n].bits(self.granularity))
>> +
>> +    def clear(self):
>> +        self._bits = set()
>> +
>> +    def clear_bits(self, bits):
>> +        self._bits = self._bits - set(bits)
> 
> Does -= not work here?
> 
> No real complaints.  Sorry.
> 
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> 

It's okay. I forget which shorthand operators Python has for which types
sometimes.

>>> a = {'a', 'b', 'c'}
>>> a -= {'c'}
>>> a
{'b', 'a'}

Well, apparently it does. I'll change it.

--js