Message139775
@skrah:
Ahh, this always happens when I don't run it :) But my point stands -- the reason why it does not crash with Numpy is that Numpy calls PyMemoryView_FromObject to obtain a new memoryview and then uses PyMemoryView_GET_BUFFER. Along this code path the refcount of self->mbuf gets properly incremented, as it's explicitly done in PyMemoryView_FromObject. However, if you have a custom object Foo which just calls `PyObject_GetBuffer`, and then do the same sequence
a = memoryview(whatever)
b = Foo(a) # --> only grabs the buffer with PyObject_GetBuffer
a.release() # --> will invalidate the buffer
b.mogrify_buffer_contents() # --> boom
Here, the buffer is released too early, as the refcount of `self->mbuf` is not incremented during the `PyObject_GetBuffer` call.
> Is there anything stopping us just storing the flags on
> PyManagedBuffer?
Slicing memoryviews can invalidate the contiguity flags, and no-strides flags, so some checks are still probably needed in `memory_getbuf`.
> It's OK if the construction API requires the flag
> information in addition to the Py_buffer struct.
This would be useful, yes. |
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Date |
User |
Action |
Args |
2011-07-04 14:36:56 | pv | set | recipients:
+ pv, teoliphant, mark.dickinson, ncoghlan, rupole, kermode, pitrou, vstinner, skrah, jcon, petri.lehtinen |
2011-07-04 14:36:56 | pv | set | messageid: <1309790216.55.0.139193640866.issue10181@psf.upfronthosting.co.za> |
2011-07-04 14:36:56 | pv | link | issue10181 messages |
2011-07-04 14:36:55 | pv | create | |
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