David Wilson added the comment: This version is tidied up enough that I think it could be reviewed.
Changes are: * Defer `buf' allocation until __init__, rather than __new__ as was previously done. Now upon completion, BytesIO.__new__ returns a valid, closed BytesIO, whereas previously a valid, empty, open BytesIO was returned. Is this interface change permissible? * Move __init__ guts into a "reinit()", for sharing with __setstate__, which also previously caused an unnecessary copy. Additionally gather up various methods for deallocating buffers into a single "reset()" function, called by reinit(), _dealloc(), and _close() * Per Stefan's suggested approach, reinit() now explicitly checks for a read-only buffer, falling back to silently performing a copy if the returned buffer is read-write. That seems vastly preferable to throwing an exception, which would probably be another interface change. * Call `unshare()` any place the buffer is about to be modified. If the buffer needs to be made private, it also accepts a size hint indicating how much less/more space the subsequent operation needs, to avoid a redundant reallocation after the unsharing. Outstanding issues: * I don't understand why buf_size is a size_t, and I'm certain the casting in unshare() is incorrect somehow. Is it simply to avoid signed overflow? ---------- Added file: http://bugs.python.org/file36004/cow2.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue22003> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
