[Checkins] [zopefoundation/zope.server] 672787: Implement OverflowableBuffer in terms of SpooledTe...

[GitHub]

  Branch: refs/heads/issue5
  Home:   https://github.com/zopefoundation/zope.server
  Commit: 672787ebcac84ebab226129edc4b5437baa69dde
      https://github.com/zopefoundation/zope.server/commit/672787ebcac84ebab226129edc4b5437baa69dde
  Author: Jason Madden <jamadden at gmail.com>
  Date:   2017-10-27 (Fri, 27 Oct 2017)

  Changed paths:
    M CHANGES.rst
    M src/zope/server/buffers.py
    M src/zope/server/tests/test_buffers.py

  Log Message:
  -----------
  Implement OverflowableBuffer in terms of SpooledTemporaryFile

Fixes #5

Even for small buffers (the 8192 that previously were guaranteed to be
kept in a simple string) this should be faster, depending on the
number of writes possibly. Previously the strbuf was built up with
concatenation: `buf = buf + data`. Now we go directly into BytesIO and
avoid the extra copying.

Microbenchmarks on Python 3.6:

In [1]: def append():
   ...:     buf = b''
   ...:     while len(buf) < 8192:
   ...:         buf += b'data' * 100
   ...:

In [4]: %timeit append()
10.9 µs ± 268 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

In [8]: def bio():
   ...:     b = io.BytesIO()
   ...:     cnt = 0
   ...:     while cnt < 8192:
   ...:         cnt += b.write(b'data'*100)
   ...:

In [9]: bio()

In [10]: %timeit bio()
8.55 µs ± 282 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)