cborutil: change buffering strategy
Profiling revealed that we were spending a lot of time on the
line that was concatenating the old buffer with the incoming data
when attempting to decode long byte strings, such as manifest
revisions.
Essentially, we were feeding N chunks of size len(X) << len(Y) into
decode() and continuously allocating a new, larger buffer to hold
the undecoded input. This created substantial memory churn and
slowed down execution.
Changing the code to aggregate pending chunks in a list until we
have enough data to fully decode the next atom makes things much
more efficient.
I don't have exact data, but I recall the old code spending >1s
on manifest fulltexts from the mozilla-unified repo. The new code
doesn't significantly appear in profile output.
Differential Revision: https://phab.mercurial-scm.org/D4854
https://bz.mercurial-scm.org/660 and:
https://bz.mercurial-scm.org/322
$ hg init
$ echo a > a
$ mkdir b
$ echo b > b/b
$ hg commit -A -m "a is file, b is dir"
adding a
adding b/b
File replaced with directory:
$ rm a
$ mkdir a
$ echo a > a/a
Should fail - would corrupt dirstate:
$ hg add a/a
abort: file 'a' in dirstate clashes with 'a/a'
[255]
Removing shadow:
$ hg rm --after a
Should succeed - shadow removed:
$ hg add a/a
Directory replaced with file:
$ rm -r b
$ echo b > b
Should fail - would corrupt dirstate:
$ hg add b
abort: directory 'b' already in dirstate
[255]
Removing shadow:
$ hg rm --after b/b
Should succeed - shadow removed:
$ hg add b
Look what we got:
$ hg st
A a/a
A b
R a
R b/b
Revert reintroducing shadow - should fail:
$ rm -r a b
$ hg revert b/b
abort: file 'b' in dirstate clashes with 'b/b'
[255]
Revert all - should succeed:
$ hg revert --all
forgetting a/a
forgetting b
undeleting a
undeleting b/b
$ hg st
Issue3423:
$ hg forget a
$ echo zed > a
$ hg revert a
$ hg st
? a.orig
$ rm a.orig
addremove:
$ rm -r a b
$ mkdir a
$ echo a > a/a
$ echo b > b
$ hg addremove -s 0
removing a
adding a/a
adding b
removing b/b
$ hg st
A a/a
A b
R a
R b/b
commit:
$ hg ci -A -m "a is dir, b is file"
$ hg st --all
C a/a
C b
Long directory replaced with file:
$ mkdir d
$ mkdir d/d
$ echo d > d/d/d
$ hg commit -A -m "d is long directory"
adding d/d/d
$ rm -r d
$ echo d > d
Should fail - would corrupt dirstate:
$ hg add d
abort: directory 'd' already in dirstate
[255]
Removing shadow:
$ hg rm --after d/d/d
Should succeed - shadow removed:
$ hg add d
$ hg ci -md
Update should work at least with clean working directory:
$ rm -r a b d
$ hg up -r 0
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg st --all
C a
C b/b
$ rm -r a b
$ hg up -r 1
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg st --all
C a/a
C b