Source: diffoscope Version: 82 Severity: wishlist Tags: patch Dear Maintainer,
Please find attached a patch optimising the feeder codepath. I don't have performance numbers, but I expect comparison to the None singleton to be faster than calling any lambda function. Cheers, Daniel [[[ >From f29fb71aba5ed79f9f517c794be2f555b762fe12 Mon Sep 17 00:00:00 2001 From: Daniel Shahaf <[email protected]> Date: Mon, 29 May 2017 15:13:53 +0000 Subject: [PATCH 1/2] diffoscope.difference: Optimize the common case. Don't call a lambda function object. --- diffoscope/difference.py | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/diffoscope/difference.py b/diffoscope/difference.py index ca45041..c1f0537 100644 --- a/diffoscope/difference.py +++ b/diffoscope/difference.py @@ -247,9 +247,13 @@ class Difference(object): self._visuals.extend(visuals) self._size_cache = None -def make_feeder_from_text_reader(in_file, filter=lambda text_buf: text_buf): - def encoding_filter(text_buf): - return filter(text_buf).encode('utf-8') +def make_feeder_from_text_reader(in_file, filter=None): + if filter: + def encoding_filter(text_buf): + return filter(text_buf).encode('utf-8') + else: + def encoding_filter(text_buf): + return text_buf.encode('utf-8') return make_feeder_from_raw_reader(in_file, encoding_filter) def make_feeder_from_command(command): @@ -264,7 +268,7 @@ def make_feeder_from_command(command): return end_nl return feeder -def make_feeder_from_raw_reader(in_file, filter=lambda buf: buf): +def make_feeder_from_raw_reader(in_file, filter=None): def feeder(out_file): max_lines = Config().max_diff_input_lines line_count = 0 @@ -274,7 +278,7 @@ def make_feeder_from_raw_reader(in_file, filter=lambda buf: buf): h = hashlib.sha1() for buf in in_file: line_count += 1 - out = filter(buf) + out = filter(buf) if filter else buf if h: h.update(out) if line_count < max_lines: ]]]
