[Python-Dev] cpython: Optimize tostringlist by taking the stream class outside the function. It's now (original) (raw)

Georg Brandl g.brandl at gmx.net
Sat Jul 21 16:43:02 CEST 2012

Uh, optimizations are not exactly what I want to see during feature freeze.

Georg

On 07/17/2012 02:10 PM, eli.bendersky wrote:

http://hg.python.org/cpython/rev/51978f89e5ed changeset: 78156:51978f89e5ed user: Eli Bendersky <eliben at gmail.com> date: Tue Jul 17 15:09:12 2012 +0300 summary: Optimize tostringlist by taking the stream class outside the function. It's now 2x faster on short calls. Related to #1767933

files: Lib/xml/etree/ElementTree.py | 38 +++++++++++++---------- 1 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py --- a/Lib/xml/etree/ElementTree.py +++ b/Lib/xml/etree/ElementTree.py @@ -1184,23 +1184,29 @@ # @defreturn sequence # @since 1.3 +class ListDataStream(io.BufferedIOBase): + """ An auxiliary stream accumulating into a list reference + """ + def init(self, lst): + self.lst = lst + + def writable(self): + return True + + def seekable(self): + return True + + def write(self, b): + self.lst.append(b) + + def tell(self): + return len(self.lst) + def tostringlist(element, encoding=None, method=None): - data = [] - class DataStream(io.BufferedIOBase): - def writable(self): - return True - - def seekable(self): - return True - - def write(self, b): - data.append(b) - - def tell(self): - return len(data) - - ElementTree(element).write(DataStream(), encoding, method=method) - return data + lst = [] + stream = ListDataStream(lst) + ElementTree(element).write(stream, encoding, method=method) + return lst ## # Writes an element tree or element structure to sys.stdout. This

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