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
$ cat >> fakepager.py <<EOF
> import sys
> for line in sys.stdin:
> sys.stdout.write('paged! %r\n' % line)
> EOF
Enable ui.formatted because pager won't fire without it, and set up
pager and tell it to use our fake pager that lets us see when the
pager was running.
$ cat >> $HGRCPATH <<EOF
> [ui]
> formatted = yes
> color = no
> [extensions]
> pager=
> [pager]
> pager = "$PYTHON" $TESTTMP/fakepager.py
> EOF
$ hg init repo
$ cd repo
$ echo a >> a
$ hg add a
$ hg ci -m 'add a'
$ for x in `"$PYTHON" $TESTDIR/seq.py 1 10`; do
> echo a $x >> a
> hg ci -m "modify a $x"
> done
By default diff and log are paged, but summary is not:
$ hg diff -c 2 --pager=yes
paged! 'diff -r f4be7687d414 -r bce265549556 a\n'
paged! '--- a/a\tThu Jan 01 00:00:00 1970 +0000\n'
paged! '+++ b/a\tThu Jan 01 00:00:00 1970 +0000\n'
paged! '@@ -1,2 +1,3 @@\n'
paged! ' a\n'
paged! ' a 1\n'
paged! '+a 2\n'
$ hg log --limit 2
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
$ hg summary
parent: 10:46106edeeb38 tip
modify a 10
branch: default
commit: (clean)
update: (current)
phases: 11 draft
We can enable the pager on summary:
$ hg --config pager.attend-summary=yes summary
paged! 'parent: 10:46106edeeb38 tip\n'
paged! ' modify a 10\n'
paged! 'branch: default\n'
paged! 'commit: (clean)\n'
paged! 'update: (current)\n'
paged! 'phases: 11 draft\n'
$ hg --config pager.attend-diff=no diff -c 2
diff -r f4be7687d414 -r bce265549556 a
--- a/a Thu Jan 01 00:00:00 1970 +0000
+++ b/a Thu Jan 01 00:00:00 1970 +0000
@@ -1,2 +1,3 @@
a
a 1
+a 2
If we completely change the attend list that's respected:
$ hg --config pager.attend=summary diff -c 2
diff -r f4be7687d414 -r bce265549556 a
--- a/a Thu Jan 01 00:00:00 1970 +0000
+++ b/a Thu Jan 01 00:00:00 1970 +0000
@@ -1,2 +1,3 @@
a
a 1
+a 2
If 'log' is in attend, then 'history' should also be paged:
$ hg history --limit 2 --config pager.attend=log
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
Possible bug: history is explicitly ignored in pager config, but
because log is in the attend list it still gets pager treatment.
$ hg history --limit 2 --config pager.attend=log \
> --config pager.ignore=history
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
Possible bug: history is explicitly marked as attend-history=no, but
it doesn't fail to get paged because log is still in the attend list.
$ hg history --limit 2 --config pager.attend-history=no
paged! 'changeset: 10:46106edeeb38\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! 'changeset: 9:6dd8ea7dd621\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
Possible bug: disabling pager for log but enabling it for history
doesn't result in history being paged.
$ hg history --limit 2 --config pager.attend-log=no \
> --config pager.attend-history=yes
changeset: 10:46106edeeb38
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 10
changeset: 9:6dd8ea7dd621
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: modify a 9
Pager should not start if stdout is not a tty.
$ hg log -l1 -q --config ui.formatted=False
10:46106edeeb38
Pager with color enabled allows colors to come through by default,
even though stdout is no longer a tty.
$ cat >> $HGRCPATH <<EOF
> [ui]
> color = always
> [color]
> mode = ansi
> EOF
$ hg log --limit 3
paged! '\x1b[0;33mchangeset: 10:46106edeeb38\x1b[0m\n'
paged! 'tag: tip\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 10\n'
paged! '\n'
paged! '\x1b[0;33mchangeset: 9:6dd8ea7dd621\x1b[0m\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 9\n'
paged! '\n'
paged! '\x1b[0;33mchangeset: 8:cff05a6312fe\x1b[0m\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'summary: modify a 8\n'
paged! '\n'
Pager works with shell aliases.
$ cat >> $HGRCPATH <<EOF
> [alias]
> echoa = !echo a
> EOF
$ hg echoa
a
$ hg --config pager.attend-echoa=yes echoa
paged! 'a\n'
Pager attributes should be copied to mq repo. Otherwise pager would be started
twice and color mode would be lost.
$ cat >> $HGRCPATH <<EOF
> [extensions]
> mq =
> EOF
$ hg init --mq
$ hg qnew foo.patch
$ hg qpop
popping foo.patch
patch queue now empty
$ hg ci --mq -m 'commit patches'
$ hg log --mq --debug
starting pager for command 'extension-via-attend-log'
paged! '\x1b[0;33mchangeset: 0:6cc2ded15503e368aaf76b6cc3d12f320c9e3b87\x1b[0m\n'
paged! 'tag: tip\n'
paged! 'phase: draft\n'
paged! 'parent: -1:0000000000000000000000000000000000000000\n'
paged! 'parent: -1:0000000000000000000000000000000000000000\n'
paged! 'manifest: 0:4980de1ae1b612014d5bcfa9507da84ce8891daa\n'
paged! 'user: test\n'
paged! 'date: Thu Jan 01 00:00:00 1970 +0000\n'
paged! 'files+: .hgignore foo.patch series\n'
paged! 'extra: branch=default\n'
paged! 'description:\n'
paged! 'commit patches\n'
paged! '\n'
paged! '\n'
Pager works with hg aliases including environment variables.
$ cat >> $HGRCPATH <<'EOF'
> [alias]
> printa = log -T "$A\n" -r 0
> EOF
$ A=1 hg --config pager.attend-printa=yes printa
paged! '1\n'
$ A=2 hg --config pager.attend-printa=yes printa
paged! '2\n'
Something that's explicitly attended is still not paginated if the
pager is globally set to off using a flag:
$ A=2 hg --config pager.attend-printa=yes printa --pager=no
2
Pager should not override the exit code of other commands
$ cat >> $TESTTMP/fortytwo.py <<'EOF'
> from mercurial import registrar, commands
> cmdtable = {}
> command = registrar.command(cmdtable)
> @command(b'fortytwo', [], b'fortytwo', norepo=True)
> def fortytwo(ui, *opts):
> ui.write(b'42\n')
> return 42
> EOF
$ cat >> $HGRCPATH <<'EOF'
> [extensions]
> fortytwo = $TESTTMP/fortytwo.py
> EOF
$ hg fortytwo --pager=on
paged! '42\n'
[42]