bundle2: extract logic for seeking bundle2 part into own class
Currently, unbundlepart classes support bi-directional seeking.
Most consumers of unbundlepart only ever seek forward - typically
as part of moving to the end of the bundle part so they can move
on to the next one. But regardless of the actual usage of the
part, instances maintain an index mapping offsets within the
underlying raw payload to offsets within the decoded payload.
Maintaining the mapping of offset data can be expensive in terms of
memory use. Furthermore, many bundle2 consumers don't have access
to an underlying seekable stream. This includes all compressed
bundles. So maintaining offset data when the underlying stream
can't be seeked anyway is wasteful. And since many bundle2 streams
can't be seeked, it seems like a bad idea to expose a seek API
in bundle2 parts by default. If you provide them, people will
attempt to use them.
Seekable bundle2 parts should be the exception, not the rule. This
commit starts the process dividing unbundlepart into 2 classes: a
base class that supports linear, one-time reads and a child class
that supports bi-directional seeking. In this first commit, we
split various methods and attributes out into a new
"seekableunbundlepart" class. Previous instantiators of "unbundlepart"
now instantiate "seekableunbundlepart." This preserves backwards
compatibility. The coupling between the classes is still tight:
"unbundlepart" cannot be used on its own. This will be addressed
in subsequent commits.
Differential Revision: https://phab.mercurial-scm.org/D1386
# enable bundle2 in advance
$ cat << EOF >> $HGRCPATH
> [format]
> usegeneraldelta=yes
> EOF
$ mkdir part1
$ cd part1
$ hg init
$ echo a > a
$ hg add a
$ hg commit -m "1"
$ hg status
$ hg copy a b
$ hg --config ui.portablefilenames=abort copy a con.xml
abort: filename contains 'con', which is reserved on Windows: con.xml
[255]
$ hg status
A b
$ hg sum
parent: 0:c19d34741b0a tip
1
branch: default
commit: 1 copied
update: (current)
phases: 1 draft
$ hg --debug commit -m "2"
committing files:
b
b: copy a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
committing manifest
committing changelog
updating the branch cache
committed changeset 1:93580a2c28a50a56f63526fb305067e6fbf739c4
we should see two history entries
$ hg history -v
changeset: 1:93580a2c28a5
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
files: b
description:
2
changeset: 0:c19d34741b0a
user: test
date: Thu Jan 01 00:00:00 1970 +0000
files: a
description:
1
we should see one log entry for a
$ hg log a
changeset: 0:c19d34741b0a
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 1
this should show a revision linked to changeset 0
$ hg debugindex a
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 3 ..... 0 b789fdd96dc2 000000000000 000000000000 (re)
we should see one log entry for b
$ hg log b
changeset: 1:93580a2c28a5
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 2
this should show a revision linked to changeset 1
$ hg debugindex b
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 65 ..... 1 37d9b5d994ea 000000000000 000000000000 (re)
this should show the rename information in the metadata
$ hg debugdata b 0 | head -3 | tail -2
copy: a
copyrev: b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
$ md5sum.py .hg/store/data/b.i
44913824c8f5890ae218f9829535922e .hg/store/data/b.i
$ hg cat b > bsum
$ md5sum.py bsum
60b725f10c9c85c70d97880dfe8191b3 bsum
$ hg cat a > asum
$ md5sum.py asum
60b725f10c9c85c70d97880dfe8191b3 asum
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
2 files, 2 changesets, 2 total revisions
$ cd ..
$ mkdir part2
$ cd part2
$ hg init
$ echo foo > foo
should fail - foo is not managed
$ hg mv foo bar
foo: not copying - file is not managed
abort: no files to copy
[255]
$ hg st -A
? foo
$ hg add foo
dry-run; print a warning that this is not a real copy; foo is added
$ hg mv --dry-run foo bar
foo has not been committed yet, so no copy data will be stored for bar.
$ hg st -A
A foo
should print a warning that this is not a real copy; bar is added
$ hg mv foo bar
foo has not been committed yet, so no copy data will be stored for bar.
$ hg st -A
A bar
should print a warning that this is not a real copy; foo is added
$ hg cp bar foo
bar has not been committed yet, so no copy data will be stored for foo.
$ hg rm -f bar
$ rm bar
$ hg st -A
A foo
$ hg commit -m1
moving a missing file
$ rm foo
$ hg mv foo foo3
foo: deleted in working directory
foo3 does not exist!
$ hg up -qC .
copy --after to a nonexistent target filename
$ hg cp -A foo dummy
foo: not recording copy - dummy does not exist
dry-run; should show that foo is clean
$ hg copy --dry-run foo bar
$ hg st -A
C foo
should show copy
$ hg copy foo bar
$ hg st -C
A bar
foo
shouldn't show copy
$ hg commit -m2
$ hg st -C
should match
$ hg debugindex foo
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 5 ..... 0 2ed2a3912a0b 000000000000 000000000000 (re)
$ hg debugrename bar
bar renamed from foo:2ed2a3912a0b24502043eae84ee4b279c18b90dd
$ echo bleah > foo
$ echo quux > bar
$ hg commit -m3
should not be renamed
$ hg debugrename bar
bar not renamed
$ hg copy -f foo bar
should show copy
$ hg st -C
M bar
foo
XXX: filtering lfilesrepo.status() in 3.3-rc causes the copy source to not be
displayed.
$ hg st -C --config extensions.largefiles=
The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
M bar
foo
$ hg commit -m3
should show no parents for tip
$ hg debugindex bar
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 69 ..... 1 7711d36246cc 000000000000 000000000000 (re)
1 69 6 ..... 2 bdf70a2b8d03 7711d36246cc 000000000000 (re)
2 75 71 ..... 3 b2558327ea8d 000000000000 000000000000 (re)
should match
$ hg debugindex foo
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 5 ..... 0 2ed2a3912a0b 000000000000 000000000000 (re)
1 5 7 ..... 2 dd12c926cf16 2ed2a3912a0b 000000000000 (re)
$ hg debugrename bar
bar renamed from foo:dd12c926cf165e3eb4cf87b084955cb617221c17
should show no copies
$ hg st -C
copy --after on an added file
$ cp bar baz
$ hg add baz
$ hg cp -A bar baz
$ hg st -C
A baz
bar
foo was clean:
$ hg st -AC foo
C foo
Trying to copy on top of an existing file fails,
$ hg copy -A bar foo
foo: not overwriting - file already committed
(hg copy --after --force to replace the file by recording a copy)
same error without the --after, so the user doesn't have to go through
two hints:
$ hg copy bar foo
foo: not overwriting - file already committed
(hg copy --force to replace the file by recording a copy)
but it's considered modified after a copy --after --force
$ hg copy -Af bar foo
$ hg st -AC foo
M foo
bar
The hint for a file that exists but is not in file history doesn't
mention --force:
$ touch xyzzy
$ hg cp bar xyzzy
xyzzy: not overwriting - file exists
(hg copy --after to record the copy)
$ cd ..