Issue 1035: bytes buffer API needs to support read locking and/or PyBUF_LOCKDATA (original) (raw)

This issue has been migrated to GitHub: https://github.com/python/cpython/issues/45376

classification

process

Created on 2007-08-27 07:42 by gregory.p.smith, last changed 2022-04-11 14:56 by admin. This issue is now closed.

Messages (7)
msg55333 - (view)	Author: Gregory P. Smith (gregory.p.smith) *	Date: 2007-08-27 07:42
I've converted _bsddb.c to use the py3k buffer API for all data and keys it takes as input. All tests now fail with this error: BufferError: Cannot make this object read-only. This presumably results from this call: PyObject_GetBuffer(obj, view, PyBUF_LOCKDATA) I need to lock the data so that the GIL can be released during database operations (I/O). Allowing bytes objects to have an immutability or readonly bit (internal or otherwise) has been a recent topic on the python-3000 mailing list; that would allow bytes' buffer API to satisfy this GetBuffer LOCKDATA request...
msg55456 - (view)	Author: Gregory P. Smith (gregory.p.smith) *	Date: 2007-08-30 03:11
I sent an initial patch to the mailing list. Its too late to be ready for 3.0a1; I'll fix it up next week.
msg55838 - (view)	Author: Gregory P. Smith (gregory.p.smith) *	Date: 2007-09-12 06:57
Attaching the most recent patch (minor update from the second one i sent to the python-3000 mailing list to initialize ob_readonly_exports = 0 in the appropriate places). Current mailing list discussion is pointing out that the name LOCKDATA means something other than what the existing pep3118 description implies and that we may want to modify the pep to support more obviously named things such as READ_LOCK, and EXCLUSIVE or similar... here's a link to the current thread: http://mail.python.org/pipermail/python-3000/2007-September/010325.html
msg56260 - (view)	Author: Brett Cannon (brett.cannon) *	Date: 2007-10-07 23:23
All the tests pass for me, Gregory. Were the failures with some patch you had only locally?
msg56263 - (view)	Author: Gregory P. Smith (gregory.p.smith) *	Date: 2007-10-08 02:56
This bug will be taken care of by PEP 3137 http://python.org/dev/peps/pep-3137/ being implemented. Anyways, no the _bsddb.c changes that I checked in do not cause a problem because I checked them in using PyBUF_SIMPLE. Until PEP 3137 is implemented the possibility of hidden data corruption due to mutable bytes objects being modified while an IO library that releases the GIL is using them remains. Feel free to close this bug in favor of something that just tracks the PEP being implemented.
msg56264 - (view)	Author: Brett Cannon (brett.cannon) *	Date: 2007-10-08 03:46
On 10/7/07, Gregory P. Smith <report@bugs.python.org> wrote: [SNIP] > Feel free to close this bug in favor of something that just tracks the > PEP being implemented. Eh, it can stay open as a reminder to double-check everything is fine once PEP 3137 goes in. It's really up to you since the bugs is assigned to you. =)
msg60168 - (view)	Author: Christian Heimes (christian.heimes) *	Date: 2008-01-19 14:21
*ping* Can this issue be closed?