mdiff: speed up showfunc for large diffs
This addresses the following issues with showfunc:
- Silly usage of regular expressions.
- Doing str.rstrip() needlessly in an inner loop.
- Doing catastrophic backtracking when trying to find a function line.
Finding function text is now at worst O(n lines in the old file), and
at best close to O(n hunks).
Given a diff like this[1]:
src/main/antlr3/uk/ac/cam/ch/wwmm/pregenerated/ChemicalChunker.g | 4 +-
src/main/java/uk/ac/cam/ch/wwmm/pregenerated/ChemicalChunkerLexer.java | 2 +-
src/main/java/uk/ac/cam/ch/wwmm/pregenerated/ChemicalChunkerParser.java | 29189 +++++----
3 files changed, 14741 insertions(+), 14454 deletions(-)
[1]: https://bitbucket.org/wwmm/chemicaltagger/changeset/d2bfbaecd4fc/raw
Without this change, hg log --stat --config diff.showfunc=1 takes an
absurdly long time to complete:
CallCount Recursive Total(ms) Inline(ms) module:lineno(function)
32813 0 80.3546 40.6086 mercurial.mdiff:160(yieldhunk)
+65062746 0 25.7227 25.7227 +<method 'match' of '_sre.SRE_Pattern' objects>
+65062746 0 14.0221 14.0221 +<method 'rstrip' of 'str' objects>
+1809 0 0.0009 0.0009 +mercurial.mdiff:148(contextend)
+1809 0 0.0003 0.0003 +<len>
65062746 0 25.7227 25.7227 <method 'match' of '_sre.SRE_Pattern' objects>
65062763 0 14.0221 14.0221 <method 'rstrip' of 'str' objects>
543 0 0.1631 0.1631 <zlib.decompress>
3 0 0.0505 0.0505 <mercurial.bdiff.blocks>
31007 0 80.4564 0.0477 mercurial.mdiff:147(_unidiff)
+32813 0 80.3546 40.6086 +mercurial.mdiff:160(yieldhunk)
+3 0 0.0505 0.0505 +<mercurial.bdiff.blocks>
+3618 0 0.0022 0.0022 +mercurial.mdiff:154(contextstart)
+5427 0 0.0013 0.0013 +<len>
+3 0 0.0001 0.0000 +re:188(compile)
1 0 80.8381 0.0322 mercurial.patch:1777(diffstatdata)
+107499 0 0.0235 0.0235 +<method 'startswith' of 'str' objects>
+31014 0 80.7820 0.0071 +mercurial.util:1284(iterlines)
+3 0 0.0000 0.0000 +<method 'search' of '_sre.SRE_Pattern' objects>
+4 0 0.0000 0.0000 +mercurial.patch:1783(addresult)
+3 0 0.0000 0.0000 +<method 'group' of '_sre.SRE_Match' objects>
6 0 0.0444 0.0283 mercurial.mdiff:12(splitnewlines)
+6 0 0.0160 0.0160 +<method 'split' of 'str' objects>
32 0 0.0246 0.0246 <method 'update' of '_hashlib.HASH' objects>
11 0 0.0236 0.0236 <method 'read' of 'file' objects>
Time: real 80.880 secs (user 80.200+0.000 sys 0.380+0.000)
With this change, it's almost as fast as not using showfunc at all:
CallCount Recursive Total(ms) Inline(ms) module:lineno(function)
543 0 0.1699 0.1699 <zlib.decompress>
3 0 0.0501 0.0501 <mercurial.bdiff.blocks>
32813 0 0.0415 0.0348 mercurial.mdiff:161(yieldhunk)
+70837 0 0.0058 0.0058 +<method 'isalnum' of 'str' objects>
+1809 0 0.0006 0.0006 +mercurial.mdiff:148(contextend)
+1809 0 0.0002 0.0002 +<len>
1 0 0.4879 0.0310 mercurial.patch:1777(diffstatdata)
+107499 0 0.0230 0.0230 +<method 'startswith' of 'str' objects>
+31014 0 0.4335 0.0065 +mercurial.util:1284(iterlines)
+3 0 0.0000 0.0000 +<method 'search' of '_sre.SRE_Pattern' objects>
+4 0 0.0000 0.0000 +mercurial.patch:1783(addresult)
+1 0 0.0004 0.0000 +re:188(compile)
32 0 0.0293 0.0293 <method 'update' of '_hashlib.HASH' objects>
6 0 0.0427 0.0279 mercurial.mdiff:12(splitnewlines)
+6 0 0.0147 0.0147 +<method 'split' of 'str' objects>
31007 0 0.1169 0.0235 mercurial.mdiff:147(_unidiff)
+3 0 0.0501 0.0501 +<mercurial.bdiff.blocks>
+32813 0 0.0415 0.0348 +mercurial.mdiff:161(yieldhunk)
+3618 0 0.0012 0.0012 +mercurial.mdiff:154(contextstart)
+5427 0 0.0006 0.0006 +<len>
107597 0 0.0230 0.0230 <method 'startswith' of 'str' objects>
16 0 0.0213 0.0213 <mercurial.mpatch.patches>
194 0 0.0149 0.0149 <method 'split' of 'str' objects>
Time: real 0.530 secs (user 0.450+0.000 sys 0.070+0.000)
$ hg init t
$ cd t
$ echo 0 > a
$ echo 0 > b
$ echo 0 > t.h
$ mkdir t
$ echo 0 > t/x
$ echo 0 > t/b
$ echo 0 > t/e.h
$ mkdir dir.h
$ echo 0 > dir.h/foo
$ hg ci -A -m m
adding a
adding b
adding dir.h/foo
adding t.h
adding t/b
adding t/e.h
adding t/x
$ touch nottracked
$ hg locate a
a
$ hg locate NONEXISTENT
[1]
$ hg locate
a
b
dir.h/foo
t.h
t/b
t/e.h
t/x
$ hg rm a
$ hg ci -m m
$ hg locate a
[1]
$ hg locate NONEXISTENT
[1]
$ hg locate relpath:NONEXISTENT
[1]
$ hg locate
b
dir.h/foo
t.h
t/b
t/e.h
t/x
$ hg locate -r 0 a
a
$ hg locate -r 0 NONEXISTENT
[1]
$ hg locate -r 0 relpath:NONEXISTENT
[1]
$ hg locate -r 0
a
b
dir.h/foo
t.h
t/b
t/e.h
t/x
-I/-X with relative path should work:
$ cd t
$ hg locate
b
dir.h/foo
t.h
t/b
t/e.h
t/x
$ hg locate -I ../t
t/b
t/e.h
t/x
Issue294: hg remove --after dir fails when dir.* also exists
$ cd ..
$ rm -r t
$ hg locate 't/**'
t/b
t/e.h
t/x
$ mkdir otherdir
$ cd otherdir
$ hg locate b
../b
../t/b
$ hg locate '*.h'
../t.h
../t/e.h
$ hg locate path:t/x
../t/x
$ hg locate 're:.*\.h$'
../t.h
../t/e.h
$ hg locate -r 0 b
../b
../t/b
$ hg locate -r 0 '*.h'
../t.h
../t/e.h
$ hg locate -r 0 path:t/x
../t/x
$ hg locate -r 0 're:.*\.h$'
../t.h
../t/e.h