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)
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ mkdir webdir
$ cd webdir
$ hg init a
$ hg --cwd a qinit -c
$ echo a > a/a
$ hg --cwd a ci -A -m a
adding a
$ echo b > a/b
$ hg --cwd a addremove
adding b
$ hg --cwd a qnew -f b.patch
$ hg --cwd a qcommit -m b.patch
$ hg --cwd a log --template "{desc}\n"
[mq]: b.patch
a
$ hg --cwd a/.hg/patches log --template "{desc}\n"
b.patch
$ root=`pwd`
$ cd ..
test with recursive collection
$ cat > collections.conf <<EOF
> [paths]
> /=$root/**
> EOF
$ hg serve -p $HGPORT -d --pid-file=hg.pid --webdir-conf collections.conf \
> -A access-paths.log -E error-paths-1.log
$ cat hg.pid >> $DAEMON_PIDS
$ "$TESTDIR/get-with-headers.py" localhost:$HGPORT '/?style=raw'
200 Script output follows
/a/
/a/.hg/patches/
$ hg qclone http://localhost:$HGPORT/a b
requesting all changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 3 changes to 3 files
updating to branch default
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --cwd b log --template "{desc}\n"
a
$ hg --cwd b qpush -a
applying b.patch
now at: b.patch
$ hg --cwd b log --template "{desc}\n"
imported patch b.patch
a
test with normal collection
$ cat > collections1.conf <<EOF
> [paths]
> /=$root/*
> EOF
$ hg serve -p $HGPORT1 -d --pid-file=hg.pid --webdir-conf collections1.conf \
> -A access-paths.log -E error-paths-1.log
$ cat hg.pid >> $DAEMON_PIDS
$ "$TESTDIR/get-with-headers.py" localhost:$HGPORT1 '/?style=raw'
200 Script output follows
/a/
/a/.hg/patches/
$ hg qclone http://localhost:$HGPORT1/a c
requesting all changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 3 changes to 3 files
updating to branch default
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --cwd c log --template "{desc}\n"
a
$ hg --cwd c qpush -a
applying b.patch
now at: b.patch
$ hg --cwd c log --template "{desc}\n"
imported patch b.patch
a
test with old-style collection
$ cat > collections2.conf <<EOF
> [collections]
> $root=$root
> EOF
$ hg serve -p $HGPORT2 -d --pid-file=hg.pid --webdir-conf collections2.conf \
> -A access-paths.log -E error-paths-1.log
$ cat hg.pid >> $DAEMON_PIDS
$ "$TESTDIR/get-with-headers.py" localhost:$HGPORT2 '/?style=raw'
200 Script output follows
/a/
/a/.hg/patches/
$ hg qclone http://localhost:$HGPORT2/a d
requesting all changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 3 changes to 3 files
updating to branch default
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --cwd d log --template "{desc}\n"
a
$ hg --cwd d qpush -a
applying b.patch
now at: b.patch
$ hg --cwd d log --template "{desc}\n"
imported patch b.patch
a
test --mq works and uses correct repository config
$ hg --cwd d outgoing --mq
comparing with http://localhost:$HGPORT2/a/.hg/patches
searching for changes
no changes found
[1]
$ hg --cwd d log --mq --template '{rev} {desc|firstline}\n'
0 b.patch