store: implement fncache basic path encoding in C
(This is not yet enabled; it will be turned on in a followup patch.)
The path encoding performed by fncache is complex and (perhaps
surprisingly) slow enough to negatively affect the overall performance
of Mercurial.
For a short path (< 120 bytes), the Python code can be reduced to a fairly
tractable state machine that either determines that nothing needs to be
done in a single pass, or performs the encoding in a second pass.
For longer paths, we avoid the more complicated hashed encoding scheme
for now, and fall back to Python.
Raw performance: I measured in a repo containing 150,000 files in its tip
manifest, with a median path name length of 57 bytes, and 95th percentile
of 96 bytes.
In this repo, the Python code takes 3.1 seconds to encode all path
names, while the hybrid C-and-Python code (called from Python) takes
0.21 seconds, for a speedup of about 14.
Across several other large repositories, I've measured the speedup from
the C code at between 26x and 40x.
For path names above 120 bytes where we must fall back to Python for
hashed encoding, the speedup is about 1.7x. Thus absolute performance
will depend strongly on the characteristics of a particular repository.
$ hg init a
$ cd a
$ echo 'root' >root
$ hg add root
$ hg commit -d '0 0' -m "Adding root node"
$ echo 'a' >a
$ hg add a
$ hg branch a
marked working directory as branch a
(branches are permanent and global, did you want a bookmark?)
$ hg commit -d '1 0' -m "Adding a branch"
$ hg branch q
marked working directory as branch q
(branches are permanent and global, did you want a bookmark?)
$ echo 'aa' >a
$ hg branch -C
reset working directory to branch a
$ hg commit -d '2 0' -m "Adding to a branch"
$ hg update -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'b' >b
$ hg add b
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ hg commit -d '2 0' -m "Adding b branch"
$ echo 'bh1' >bh1
$ hg add bh1
$ hg commit -d '3 0' -m "Adding b branch head 1"
$ hg update -C 2
1 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo 'bh2' >bh2
$ hg add bh2
$ hg commit -d '4 0' -m "Adding b branch head 2"
$ echo 'c' >c
$ hg add c
$ hg branch c
marked working directory as branch c
(branches are permanent and global, did you want a bookmark?)
$ hg commit -d '5 0' -m "Adding c branch"
$ hg branch tip
abort: the name 'tip' is reserved
[255]
$ hg branch null
abort: the name 'null' is reserved
[255]
$ hg branch .
abort: the name '.' is reserved
[255]
$ echo 'd' >d
$ hg add d
$ hg branch 'a branch name much longer than the default justification used by branches'
marked working directory as branch a branch name much longer than the default justification used by branches
(branches are permanent and global, did you want a bookmark?)
$ hg commit -d '6 0' -m "Adding d branch"
$ hg branches
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 4:aee39cd168d0
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
-------
$ hg branches -a
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 4:aee39cd168d0
--- Branch a
$ hg log -b a
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 2:881fe2b92ad0
branch: a
user: test
date: Thu Jan 01 00:00:02 1970 +0000
summary: Adding to a branch
changeset: 1:dd6b440dd85a
branch: a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: Adding a branch
---- Branch b
$ hg log -b b
changeset: 4:aee39cd168d0
branch: b
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: Adding b branch head 1
changeset: 3:ac22033332d1
branch: b
parent: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:02 1970 +0000
summary: Adding b branch
---- going to test branch closing
$ hg branches
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 4:aee39cd168d0
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg up -C b
2 files updated, 0 files merged, 4 files removed, 0 files unresolved
$ echo 'xxx1' >> b
$ hg commit -d '7 0' -m 'adding cset to branch b'
$ hg up -C aee39cd168d0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo 'xxx2' >> b
$ hg commit -d '8 0' -m 'adding head to branch b'
created new head
$ echo 'xxx3' >> b
$ hg commit -d '9 0' -m 'adding another cset to branch b'
$ hg branches
b 10:bfbe841b666e
a branch name much longer than the default justification used by branches 7:10ff5895aa57
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg heads --closed
changeset: 10:bfbe841b666e
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: adding another cset to branch b
changeset: 8:eebb944467c9
branch: b
parent: 4:aee39cd168d0
user: test
date: Thu Jan 01 00:00:07 1970 +0000
summary: adding cset to branch b
changeset: 7:10ff5895aa57
branch: a branch name much longer than the default justification used by branches
user: test
date: Thu Jan 01 00:00:06 1970 +0000
summary: Adding d branch
changeset: 6:589736a22561
branch: c
user: test
date: Thu Jan 01 00:00:05 1970 +0000
summary: Adding c branch
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
$ hg heads
changeset: 10:bfbe841b666e
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: adding another cset to branch b
changeset: 8:eebb944467c9
branch: b
parent: 4:aee39cd168d0
user: test
date: Thu Jan 01 00:00:07 1970 +0000
summary: adding cset to branch b
changeset: 7:10ff5895aa57
branch: a branch name much longer than the default justification used by branches
user: test
date: Thu Jan 01 00:00:06 1970 +0000
summary: Adding d branch
changeset: 6:589736a22561
branch: c
user: test
date: Thu Jan 01 00:00:05 1970 +0000
summary: Adding c branch
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
$ hg commit -d '9 0' --close-branch -m 'prune bad branch'
$ hg branches -a
b 8:eebb944467c9
a branch name much longer than the default justification used by branches 7:10ff5895aa57
$ hg up -C b
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg commit -d '9 0' --close-branch -m 'close this part branch too'
--- b branch should be inactive
$ hg branches
a branch name much longer than the default justification used by branches 7:10ff5895aa57
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg branches -c
a branch name much longer than the default justification used by branches 7:10ff5895aa57
b 12:e3d49c0575d8 (closed)
c 6:589736a22561 (inactive)
a 5:d8cbc61dbaa6 (inactive)
default 0:19709c5a4e75 (inactive)
$ hg branches -a
a branch name much longer than the default justification used by branches 7:10ff5895aa57
$ hg branches -q
a branch name much longer than the default justification used by branches
c
a
default
$ hg heads b
no open branch heads found on branches b
[1]
$ hg heads --closed b
changeset: 12:e3d49c0575d8
branch: b
tag: tip
parent: 8:eebb944467c9
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: close this part branch too
changeset: 11:d3f163457ebf
branch: b
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: prune bad branch
$ echo 'xxx4' >> b
$ hg commit -d '9 0' -m 'reopen branch with a change'
reopening closed branch head 12
--- branch b is back in action
$ hg branches -a
b 13:e23b5505d1ad
a branch name much longer than the default justification used by branches 7:10ff5895aa57
---- test heads listings
$ hg heads
changeset: 13:e23b5505d1ad
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: reopen branch with a change
changeset: 7:10ff5895aa57
branch: a branch name much longer than the default justification used by branches
user: test
date: Thu Jan 01 00:00:06 1970 +0000
summary: Adding d branch
changeset: 6:589736a22561
branch: c
user: test
date: Thu Jan 01 00:00:05 1970 +0000
summary: Adding c branch
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
branch default
$ hg heads default
changeset: 0:19709c5a4e75
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Adding root node
branch a
$ hg heads a
changeset: 5:d8cbc61dbaa6
branch: a
parent: 2:881fe2b92ad0
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: Adding b branch head 2
$ hg heads --active a
no open branch heads found on branches a
[1]
branch b
$ hg heads b
changeset: 13:e23b5505d1ad
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: reopen branch with a change
$ hg heads --closed b
changeset: 13:e23b5505d1ad
branch: b
tag: tip
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: reopen branch with a change
changeset: 11:d3f163457ebf
branch: b
user: test
date: Thu Jan 01 00:00:09 1970 +0000
summary: prune bad branch
default branch colors:
$ echo "[extensions]" >> $HGRCPATH
$ echo "color =" >> $HGRCPATH
$ echo "[color]" >> $HGRCPATH
$ echo "mode = ansi" >> $HGRCPATH
$ hg up -C c
3 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg commit -d '9 0' --close-branch -m 'reclosing this branch'
$ hg up -C b
2 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ hg branches --color=always
\x1b[0;32mb\x1b[0m \x1b[0;33m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m \x1b[0;33m7:10ff5895aa57\x1b[0m (esc)
\x1b[0;0ma\x1b[0m \x1b[0;33m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;0mdefault\x1b[0m \x1b[0;33m 0:19709c5a4e75\x1b[0m (inactive) (esc)
default closed branch color:
$ hg branches --color=always --closed
\x1b[0;32mb\x1b[0m \x1b[0;33m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;0ma branch name much longer than the default justification used by branches\x1b[0m \x1b[0;33m7:10ff5895aa57\x1b[0m (esc)
\x1b[0;30;1mc\x1b[0m \x1b[0;33m 14:f894c25619d3\x1b[0m (closed) (esc)
\x1b[0;0ma\x1b[0m \x1b[0;33m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;0mdefault\x1b[0m \x1b[0;33m 0:19709c5a4e75\x1b[0m (inactive) (esc)
$ echo "[extensions]" >> $HGRCPATH
$ echo "color =" >> $HGRCPATH
$ echo "[color]" >> $HGRCPATH
$ echo "branches.active = green" >> $HGRCPATH
$ echo "branches.closed = blue" >> $HGRCPATH
$ echo "branches.current = red" >> $HGRCPATH
$ echo "branches.inactive = magenta" >> $HGRCPATH
$ echo "log.changeset = cyan" >> $HGRCPATH
custom branch colors:
$ hg branches --color=always
\x1b[0;31mb\x1b[0m \x1b[0;36m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m \x1b[0;36m7:10ff5895aa57\x1b[0m (esc)
\x1b[0;35ma\x1b[0m \x1b[0;36m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;35mdefault\x1b[0m \x1b[0;36m 0:19709c5a4e75\x1b[0m (inactive) (esc)
custom closed branch color:
$ hg branches --color=always --closed
\x1b[0;31mb\x1b[0m \x1b[0;36m 13:e23b5505d1ad\x1b[0m (esc)
\x1b[0;32ma branch name much longer than the default justification used by branches\x1b[0m \x1b[0;36m7:10ff5895aa57\x1b[0m (esc)
\x1b[0;34mc\x1b[0m \x1b[0;36m 14:f894c25619d3\x1b[0m (closed) (esc)
\x1b[0;35ma\x1b[0m \x1b[0;36m 5:d8cbc61dbaa6\x1b[0m (inactive) (esc)
\x1b[0;35mdefault\x1b[0m \x1b[0;36m 0:19709c5a4e75\x1b[0m (inactive) (esc)
$ cd ..