filelog: wrap revlog instead of inheriting it (API)
The revlog base class exposes a ton of methods. Inheriting the
revlog class for filelog will make it difficult to expose a
clean interface. There will be abstraction violations.
This commit breaks the inheritance of revlog by the filelog
class. Filelog instances now contain a reference to a revlog
instance. Various properties and methods are now proxied to
that instance.
There is precedence for doing this: manifestlog does something
similar. Although, manifestlog has a cleaner interface than
filelog. We'll get there with filelog...
The new filelog class exposes a handful of extra properties and
methods that aren't part of the declared filelog interface.
Every extra item was added in order to get a test to pass. The
set of tests that failed without these extra proxies has
significant overlap with the set of tests that don't work with
the simple store repo. There should be no surprise there.
Hopefully the hardest part about this commit to review are the
changes to bundlerepo and unionrepo. Both repository types
define a custom revlog or revlog-like class and then have a
custom filelog that inherits from both filelog and their custom
revlog. This code has been changed so the filelog types don't
inherit from revlog. Instead, they replace the revlog instance
on the created filelog. This is super hacky. I plan to fix this
in a future commit by parameterizing filelog.__init__.
Because Python function call overhead is a thing, this change
could impact performance by introducing a nearly empty proxy
function for various methods and properties. I would gladly
measure the performance impact of it, but I'm not sure what
operations have tight loops over filelog attribute lookups
or function calls. I know some of the DAG traversal code can
be sensitive about the performance of e.g. parentrevs(). However,
many of these functions are implemented on the revlog class and
therefore have direct access to self.parentrevs() and aren't
going through a proxy.
.. api::
filelog.filelog is now a standalone class and doesn't inherit
from revlog. Instead, it wraps a revlog instance at self._revlog.
This change was made in an attempt to formalize storage APIs and
prevent revlog implementation details leaking through to callers.
Differential Revision: https://phab.mercurial-scm.org/D3154
#require tla symlink
$ tla my-id "mercurial <mercurial@mercurial-scm.org>"
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert=" >> $HGRCPATH
create tla archive
$ tla make-archive tla@mercurial--convert `pwd`/hg-test-convert-tla
initialize tla repo
$ mkdir tla-repo
$ cd tla-repo/
$ tla init-tree tla@mercurial--convert/tla--test--0
$ tla import
* creating version tla@mercurial--convert/tla--test--0
* imported tla@mercurial--convert/tla--test--0
create initial files
$ echo 'this is a file' > a
$ tla add a
$ mkdir src
$ tla add src
$ cd src
$ dd count=1 if=/dev/zero of=b > /dev/null 2> /dev/null
$ tla add b
$ tla commit -s "added a file, src and src/b (binary)"
A/ .arch-ids
A/ src
A/ src/.arch-ids
A .arch-ids/a.id
A a
A src/.arch-ids/=id
A src/.arch-ids/b.id
A src/b
* update pristine tree (tla@mercurial--convert/tla--test--0--base-0 => tla--test--0--patch-1)
* committed tla@mercurial--convert/tla--test--0--patch-1
create link file and modify a
$ ln -s ../a a-link
$ tla add a-link
$ echo 'this a modification to a' >> ../a
$ tla commit -s "added link to a and modify a"
A src/.arch-ids/a-link.id
A src/a-link
M a
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-1 => tla--test--0--patch-2)
* committed tla@mercurial--convert/tla--test--0--patch-2
create second link and modify b
$ ln -s ../a a-link-2
$ tla add a-link-2
$ dd count=1 seek=1 if=/dev/zero of=b > /dev/null 2> /dev/null
$ tla commit -s "added second link and modify b"
A src/.arch-ids/a-link-2.id
A src/a-link-2
Mb src/b
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-2 => tla--test--0--patch-3)
* committed tla@mercurial--convert/tla--test--0--patch-3
b file to link and a-link-2 to regular file
$ rm -f a-link-2
$ echo 'this is now a regular file' > a-link-2
$ ln -sf ../a b
$ tla commit -s "file to link and link to file test"
fl src/b
lf src/a-link-2
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-3 => tla--test--0--patch-4)
* committed tla@mercurial--convert/tla--test--0--patch-4
move a-link-2 file and src directory
$ cd ..
$ tla mv src/a-link-2 c
$ tla mv src test
$ tla commit -s "move and rename a-link-2 file and src directory"
D/ src/.arch-ids
A/ test/.arch-ids
/> src test
=> src/.arch-ids/a-link-2.id .arch-ids/c.id
=> src/a-link-2 c
=> src/.arch-ids/=id test/.arch-ids/=id
=> src/.arch-ids/a-link.id test/.arch-ids/a-link.id
=> src/.arch-ids/b.id test/.arch-ids/b.id
* update pristine tree (tla@mercurial--convert/tla--test--0--patch-4 => tla--test--0--patch-5)
* committed tla@mercurial--convert/tla--test--0--patch-5
$ cd ..
converting tla repo to Mercurial
$ hg convert tla-repo tla-repo-hg
initializing destination tla-repo-hg repository
analyzing tree version tla@mercurial--convert/tla--test--0...
scanning source...
sorting...
converting...
5 initial import
4 added a file, src and src/b (binary)
3 added link to a and modify a
2 added second link and modify b
1 file to link and link to file test
0 move and rename a-link-2 file and src directory
$ tla register-archive -d tla@mercurial--convert
$ glog()
> {
> hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@"
> }
show graph log
$ glog -R tla-repo-hg
o 5 "move and rename a-link-2 file and src directory" files: c src/a-link src/a-link-2 src/b test/a-link test/b
|
o 4 "file to link and link to file test" files: src/a-link-2 src/b
|
o 3 "added second link and modify b" files: src/a-link-2 src/b
|
o 2 "added link to a and modify a" files: a src/a-link
|
o 1 "added a file, src and src/b (binary)" files: a src/b
|
o 0 "initial import" files:
$ hg up -q -R tla-repo-hg
$ hg -R tla-repo-hg manifest --debug
c4072c4b72e1cabace081888efa148ee80ca3cbb 644 a
0201ac32a3a8e86e303dff60366382a54b48a72e 644 c
c0067ba5ff0b7c9a3eb17270839d04614c435623 644 @ test/a-link
375f4263d86feacdea7e3c27100abd1560f2a973 644 @ test/b