zstd: vendor python-zstandard 0.5.0
As the commit message for the previous changeset says, we wish
for zstd to be a 1st class citizen in Mercurial. To make that
happen, we need to enable Python to talk to the zstd C API. And
that requires bindings.
This commit vendors a copy of existing Python bindings. Why do we
need to vendor? As the commit message of the previous commit says,
relying on systems in the wild to have the bindings or zstd present
is a losing proposition. By distributing the zstd and bindings with
Mercurial, we significantly increase our chances that zstd will
work. Since zstd will deliver a better end-user experience by
achieving better performance, this benefits our users. Another
reason is that the Python bindings still aren't stable and the
API is somewhat fluid. While Mercurial could be coded to target
multiple versions of the Python bindings, it is safer to bundle
an explicit, known working version.
The added Python bindings are mostly a fully-featured interface
to the zstd C API. They allow one-shot operations, streaming,
reading and writing from objects implements the file object
protocol, dictionary compression, control over low-level compression
parameters, and more. The Python bindings work on Python 2.6,
2.7, and 3.3+ and have been tested on Linux and Windows. There are
CFFI bindings, but they are lacking compared to the C extension.
Upstream work will be needed before we can support zstd with PyPy.
But it will be possible.
The files added in this commit come from Git commit
e637c1b214d5f869cf8116c550dcae23ec13b677 from
https://github.com/indygreg/python-zstandard and are added without
modifications. Some files from the upstream repository have been
omitted, namely files related to continuous integration.
In the spirit of full disclosure, I'm the maintainer of the
"python-zstandard" project and have authored 100% of the code
added in this commit. Unfortunately, the Python bindings have
not been formally code reviewed by anyone. While I've tested
much of the code thoroughly (I even have tests that fuzz APIs),
there's a good chance there are bugs, memory leaks, not well
thought out APIs, etc. If someone wants to review the code and
send feedback to the GitHub project, it would be greatly
appreciated.
Despite my involvement with both projects, my opinions of code
style differ from Mercurial's. The code in this commit introduces
numerous code style violations in Mercurial's linters. So, the code
is excluded from most lints. However, some violations I agree with.
These have been added to the known violations ignore list for now.
$ echo '[extensions]' >> $HGRCPATH
$ echo 'hgext.mq =' >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo foo > foo
$ hg ci -qAm 'add a file'
$ hg qinit
$ hg qnew foo
$ echo foo >> foo
$ hg qrefresh -m 'append foo'
$ hg qnew bar
$ echo bar >> foo
$ hg qrefresh -m 'append bar'
Try to operate on public mq changeset
$ hg qpop
popping bar
now at: foo
$ hg phase --public qbase
$ echo babar >> foo
$ hg qref
abort: cannot qrefresh public revision
(see 'hg help phases' for details)
[255]
$ hg revert -a
reverting foo
$ hg qpop
abort: popping would remove a public revision
(see 'hg help phases' for details)
[255]
$ hg qfold bar
abort: cannot qrefresh public revision
(see 'hg help phases' for details)
[255]
$ hg revert -a
reverting foo
restore state for remaining test
$ hg qpush
applying bar
now at: bar
try to commit on top of a patch
$ echo quux >> foo
$ hg ci -m 'append quux'
abort: cannot commit over an applied mq patch
[255]
cheat a bit...
$ mv .hg/patches .hg/patches2
$ hg ci -m 'append quux'
$ mv .hg/patches2 .hg/patches
qpop/qrefresh on the wrong revision
$ hg qpop
abort: popping would remove a revision not managed by this patch queue
[255]
$ hg qpop -n patches
using patch queue: $TESTTMP/repo/.hg/patches (glob)
abort: popping would remove a revision not managed by this patch queue
[255]
$ hg qrefresh
abort: working directory revision is not qtip
[255]
$ hg up -C qtip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg qpop
abort: popping would remove a revision not managed by this patch queue
[255]
$ hg qrefresh
abort: cannot qrefresh a revision with children
[255]
$ hg tip --template '{rev} {desc}\n'
3 append quux
qpush warning branchheads
$ cd ..
$ hg init branchy
$ cd branchy
$ echo q > q
$ hg add q
$ hg qnew -f qp
$ hg qpop
popping qp
patch queue now empty
$ echo a > a
$ hg ci -Ama
adding a
$ hg up null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ echo c > c
$ hg ci -Amc
adding c
$ hg merge default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -mmerge
$ hg up default
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg log
changeset: 2:65309210bf4e
branch: b
tag: tip
parent: 1:707adb4c8ae1
parent: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: merge
changeset: 1:707adb4c8ae1
branch: b
parent: -1:000000000000
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: c
changeset: 0:cb9a9f314b8b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a
$ hg qpush
applying qp
now at: qp
Testing applied patches, push and --force
$ cd ..
$ hg init forcepush
$ cd forcepush
$ echo a > a
$ hg ci -Am adda
adding a
$ echo a >> a
$ hg ci -m changea
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg branch branch
marked working directory as branch branch
(branches are permanent and global, did you want a bookmark?)
$ echo b > b
$ hg ci -Am addb
adding b
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg --cwd .. clone -r 0 forcepush forcepush2
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo a >> a
$ hg qnew patch
Pushing applied patch with --rev without --force
$ hg push -r . ../forcepush2
pushing to ../forcepush2
abort: source has mq patches applied
[255]
Pushing applied patch with branchhash, without --force
$ hg push ../forcepush2#default
pushing to ../forcepush2
abort: source has mq patches applied
[255]
Pushing revs excluding applied patch
$ hg push --new-branch -r 'branch(branch)' -r 2 ../forcepush2
pushing to ../forcepush2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
Pushing applied patch with --force
$ hg phase --force --secret 'mq()'
$ hg push --force -r default ../forcepush2
pushing to ../forcepush2
searching for changes
no changes found (ignored 1 secret changesets)
[1]
$ hg phase --draft 'mq()'
$ hg push --force -r default ../forcepush2
pushing to ../forcepush2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
$ cd ..