util: create new abstraction for compression engines
Currently, util.py has "compressors" and "decompressors" dicts
mapping compression algorithms to callables returning objects that
perform well-defined operations. In addition, revlog.py has code
for calling into a compressor or decompressor explicitly. And, there
is code in the wire protocol for performing zlib compression.
The 3rd party lz4revlog extension has demonstrated the utility of
supporting alternative compression formats for revlog storage. But
it stops short of supporting lz4 for bundles and the wire protocol.
There are also plans to support zstd as a general compression
replacement.
So, there appears to be a market for a unified API for registering
compression engines. This commit starts the process of establishing
one.
This commit establishes a base class/interface for defining
compression engines and how they will be used. A collection class
to hold references to registered compression engines has also been
introduced.
The built-in zlib, bz2, truncated bz2, and no-op compression engines
are registered with a singleton instance of the collection class.
The compression engine API will change once consumers are ported
to the new API and some common patterns can be simplified at the
engine API level. So don't get too attached to the API...
$ 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 ..