Summary:
I did some extra xdiff changes in upstream, namely:
- Remove unused features
- Replace "long" (32-bit in MSVC) with int64_t to support large files
- Add comment on some key variables
This backports them. It also includes Matt's fixes about Windows compatibility.
Reviewed By: ryanmce
Differential Revision: D7223939
fbshipit-source-id: 9287d5be22dae4ab41b05b3a4c160d836b5714a6
Summary:
Enable the indent heuristic feature, since it provides nice visual
improvements for a wide range of cases. See the added test, and [1].
The only downside is it can slow things down. In a crafted case, this could
make `--indent-heuristic` several times slower than `--no-indent-heuristic`.
```
open('a', 'w').write(" \n" * 1000000)
open('b', 'w').write(" \n" * 1000001)
```
```
git diff --no-indent-heuristic a b 0.21s user 0.03s system 100% cpu 0.239 total
git diff --indent-heuristic a b 0.77s user 0.02s system 99% cpu 0.785 total
```
[1]: 433860f3d0
Reviewed By: ryanmce
Differential Revision: D7135452
fbshipit-source-id: 019b7e89225f288bba0a1d042591b13b5419ad0e
Summary:
Implement a `mercurial.cext.xdiff` module that exposes the xdiff algorithm.
`xdiff.blocks` should be a drop-in replacement for `bdiff.blocks`.
In theory we can change the pure C version of `bdiff.c` directly. However
that means we lose bdiff entirely. It seems more flexible to have both at
the same time so they can be easily switched via Python code. Hence the
Python module approach.
Reviewed By: ryanmce
Differential Revision: D7135205
fbshipit-source-id: 48cd3b5be7fd5ef41b64eab6c76a5c8a6ce99e05
Summary:
Exposed by UBSAN:
```lang=bash
scm/hg/mercurial/cext/pathencode.c:61:40: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'
#0 0x7f60c372b2e7 in inset scm/hg/mercurial/cext/pathencode.c:61
#1 0x7f60c373022c in _encode scm/hg/mercurial/cext/pathencode.c:424
#2 0x7f60c372a605 in basicencode scm/hg/mercurial/cext/pathencode.c:480
#3 0x7f60c3729f90 in pathencode scm/hg/mercurial/cext/pathencode.c:744
```
Use unsinged 1 in the shift operation to fix the UB
Reviewed By: wez
Differential Revision: D7073320
fbshipit-source-id: 8e714c41e94474c4c62b3b6730df6fe99f9c0391
Summary:
Adds some basic building blocks to build hg using buck.
Header files are cleaned up, so they are relative to the project root.
Some minor changes to C code are made to remove clang build
warnings.
Rust dependencies, fb-hgext C/Python dependencies (ex. cstore,
mysql-connector), and 3rd-party dependencies like python-lz4
are not built yet. But the built hg binary should be able to run
most tests just fine.
Reviewed By: wez
Differential Revision: D6814686
fbshipit-source-id: 59eefd5a3ad86db2ad1c821ed824c9f1878c93e4
Summary: Based on feedback to D6687860.
Test Plan: n/a
Reviewers: durham, #mercurial
Reviewed By: durham
Differential Revision: https://phabricator.intern.facebook.com/D6714211
Signature: 6714211:1515788399:386b8f7330f343349234d1f317e5ac0a594142cf
Signals could be blocked by something like:
#include <unistd.h>
#include <signal.h>
int main(int argc, char * const argv[]) {
sigset_t set;
sigfillset(&set);
sigprocmask(SIG_BLOCK, &set, NULL);
execv("/bin/hg", argv);
return 0;
}
One of the problems is if SIGCHLD is blocked, chgserver would not reap
zombie workers since it depends on SIGCHLD handler entirely.
While it's the parent process to blame but it seems a good idea to just
unblock the signal from hg. FWIW git does that for SIGPIPE already [1].
Unfortunately Python 2 does not reset or provide APIs to change signal
masks. Therefore let's add one in osutil. Note: Python 3.3 introduced
`signal.pthread_sigmask` which solves the problem.
`sigprocmask` is part of POSIX [2] so there is no feature testing in
`setup.py`.
[1]: 7559a1be8a
[2]: http://pubs.opengroup.org/onlinepubs/7908799/xsh/sigprocmask.html
Differential Revision: https://phab.mercurial-scm.org/D1736
Change the C implementation of phasecache.loadphaserevs to provide only
the sets for draft and secret phase as well as the number of revisions
seen.
Change the pure Python implementation of the same functino to compute
the sets instead of the list of phases for each revision.
Change phasecache.phase to check the phase sets and assume public if the
revision is in neither draft nor secret set. This is computationally
slightly more expensive.
Change phasecache.getrevset for public() based queries to compute the
set of non-matching revisions and return the result as filtered
fullreposet. A shortcut is taken when no draft or secret revision
exists.
Bump the module version for the changed interface contract.
Overall, this saves around 16 Bytes per revision whenever the phasecache
is used, for the test case in issue5691 it is around 3MB. getrevset()
for a large repository is around 13% slower here, that seems an
acceptable trade off. Performance impact for phase() should be similar.
Differential Revision: https://phab.mercurial-scm.org/D1606
# skip-blame because parsers.c is mechanically rewritten by
clang-format with no semantic change.
Differential Revision: https://phab.mercurial-scm.org/D1170
This gives clang-format the right notion about formatting these struct
initializers, therefore allowing us to automatically format several
additional files.
# skip-blame because this is just a content-free comment addition
Differential Revision: https://phab.mercurial-scm.org/D1169
We want a slightly weird format here so that it's easier to read, but
in order to preserve that we need to disable clang-format.
Differential Revision: https://phab.mercurial-scm.org/D1168
This seems to be the prevailing style, even though it is a bit more
verbose for very simple switch statements.
Differential Revision: https://phab.mercurial-scm.org/D909
We mostly abide by this style.
In one case, a blank line was inserted to prevent a local
`#include "file"` from coming before a `#include <file>`.
Differential Revision: https://phab.mercurial-scm.org/D908
The minimum input size to exploit is ~682MB (= INT_MAX / len('\\u0000') * 2)
on 32bit system, which isn't easy to achieve using Python str in 2GB process
address space, but probably doable.
This extracts charencode.c from parsers.c, which seems big enough for me
to hesitate to add new JSON functions. Still charencode.o is linked to
parsers.so to avoid duplication of binary codes.
find_deepest is used to find the "best" ancestors given a list. In the main
loop it keeps an invariant called 'ninteresting' which is supposed to contain
the number of non-zero entries in the 'interesting' array. This invariant is
incorrectly maintained, however, which leads the the algorithm returning an
empty result for certain graphs. This has been fixed.
Also, the 'interesting' array is supposed to fit 2^ancestors values, but is
incorrectly allocated to twice that size. This has been fixed as well.
The tests in test-ancestor.py compare the Python and C versions of the code,
and report the error correctly, since the Python version works correct. Even
so, I have added an additional test against the expected result, in the event
that both algorithms have an identical error in the future.
This fixes issue5623.
* Scope of "value" is reduced
* index_baserev() is documented
* Error is no longer redundantly set for -2 return values
* Error values are compared <= -2 instead of == -2 to protect
against odd failure scenarios
I've seen revlog._deltachain() appear in a number of performance
profiles. I suspect there are 2 reasons for this:
1. Delta chain resolution performs many index lookups, thus triggering
population of index tuples. Creating possibly tens of thousands of
PyObject will have overhead.
2. Delta chain resolution is a tight loop.
By moving delta chain resolution to C, we can defer instantiation
of full index entry tuples and make the loop faster courtesy of
not running in Python.
We can measure the impact to delta chain resolution via
`hg perflogrevision` using the mozilla-central repo with a recent
manifest having delta chain length of 33726:
$ hg perfrevlogrevision -m 364895
! full
! wall 0.367585 comb 0.370000 user 0.340000 sys 0.030000 (best of 27)
! wall 0.357581 comb 0.360000 user 0.350000 sys 0.010000 (best of 28)
! deltachain
! wall 0.010644 comb 0.010000 user 0.010000 sys 0.000000 (best of 270)
! wall 0.000292 comb 0.000000 user 0.000000 sys 0.000000 (best of 8729)
$ hg perfrevlogrevision --cache -m 364895
! deltachain
! wall 0.003904 comb 0.000000 user 0.000000 sys 0.000000 (best of 712)
! wall 0.000284 comb 0.000000 user 0.000000 sys 0.000000 (best of 9926)
The first test measures savings from both not instantiating index
entries and moving to C. The second test (which doesn't clear the
index caches) essentially isolates the benefits of moving from Python
to C. It still shows a 13.7x speedup (versus 36.4x). And there are
multiple milliseconds of savings within the critical path for resolving
revision data. I think that justifies the existence of C code.
A more striking example of the benefits of this change can be
demonstrated by timing `hg debugdeltachain -m` for the mozilla-central
repo:
$ time hg debugdeltachain -m > /dev/null
before: 1057.4s
after: 503.3s
PyPy2.7 5.8.0: 220.0s
It's worth noting that the C code isn't as optimal as it could be.
We're still instantiating a new PyObject for every revision. A future
optimization would be to reuse the PyObject on the cached index tuple.
We could potentially also get wins by using a memory array of raw
integers. There is also room for a delta chain cache on revlog
instances. Of course, the best optimization is to implement revlog
reading outside of Python so Python doesn't need to be concerned
about the relatively expensive index entries and operations on them.
parsers.c is ~3000 lines and ~2/3 of it is related to the revlog
index type.
We already have separate C source files for directory utilities
and manifest parsing. I think the quite unwieldy revlog/index
parsing code should be self-contained as well.
I performed the extraction as a file copy then removed content
from both sides in order to preserve file history and blame.
As part of this, I also had to move the hexdigit table and
function to a shared header since it is used by both parsers.c
and revlog.c
# no-check-commit
I'm going to restructure cext/pure modules and get rid of our hgimporter
hack. C extension modules will be moved to cext/ directory so old and new
compiled modules can coexist in development tree. This is necessary to
run 'hg bisect' without recompiling.
New extension modules will be loaded by an importer function:
base85 = policy.importmod('base85') # select pure.base85 or cext.base85
This will also allow us to split cffi from pure modules, which is currently
difficult because pure modules can't be imported by name.
