view tests/fakepatchtime.py @ 47120:7109a38830c9

dirstate-tree: Fold "tracked descendants" counter update in main walk

For the purpose of implementing `has_tracked_dir` (which means "has tracked
descendants) without an expensive sub-tree traversal, we maintaing a counter
of tracked descendants on each "directory" node of the tree-shaped dirstate.

Before this changeset, mutating or inserting a node at a given path would
involve:

* Walking the tree from root through ancestors to find the node or the spot
  where to insert it
* Looking at the previous node if any to decide what counter update is needed
* Performing any node mutation
* Walking the tree *again* to update counters in ancestor nodes

When profiling `hg status` on a large repo, this second walk takes times
while loading a the dirstate from disk.

It turns out we have enough information to decide before he first tree walk
what counter update is needed. This changeset merges the two walks, gaining
~10% of the total time for `hg update` (in the same hyperfine benchmark as
the previous changeset).

---

Profiling was done by compiling with this `.cargo/config`:

    [profile.release]
    debug = true

then running with:

    py-spy record -r 500 -n -o /tmp/hg.json --format speedscope -- \
    ./hg status -R $REPO --config experimental.dirstate-tree.in-memory=1

then visualizing the recorded JSON file in https://www.speedscope.app/

Differential Revision: https://phab.mercurial-scm.org/D10554

# extension to emulate invoking 'patch.internalpatch()' at the time
# specified by '[fakepatchtime] fakenow'

from __future__ import absolute_import

from mercurial import (
    extensions,
    patch as patchmod,
    registrar,
)
from mercurial.utils import dateutil

configtable = {}
configitem = registrar.configitem(configtable)

configitem(
    b'fakepatchtime',
    b'fakenow',
    default=None,
)


def internalpatch(
    orig,
    ui,
    repo,
    patchobj,
    strip,
    prefix=b'',
    files=None,
    eolmode=b'strict',
    similarity=0,
):
    if files is None:
        files = set()
    r = orig(
        ui,
        repo,
        patchobj,
        strip,
        prefix=prefix,
        files=files,
        eolmode=eolmode,
        similarity=similarity,
    )

    fakenow = ui.config(b'fakepatchtime', b'fakenow')
    if fakenow:
        # parsing 'fakenow' in YYYYmmddHHMM format makes comparison between
        # 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy
        fakenow = dateutil.parsedate(fakenow, [b'%Y%m%d%H%M'])[0]
        for f in files:
            repo.wvfs.utime(f, (fakenow, fakenow))

    return r


def extsetup(ui):
    extensions.wrapfunction(patchmod, 'internalpatch', internalpatch)