view contrib/undumprevlog @ 41188:006c9ce486fa

rust-cpython: bindings for MissingAncestors

The exposition is rather straightforward, except for the
remove_ancestors_from() method, which forces us to an inefficient
conversion between Python sets and Rust HashSets.

Two alternatives are proposed in comments:

- changing the inner API to "emit" the revision numbers to discard
  this would be a substantial change, and it would be better only in the
  cases where there are more to retain than to discard
- mutating the Python set directly: this would force us to define an abstract
  `RevisionSet` trait, and implement it both for plain `HashSet` and for
  a struct enclosing a Python set with the GIL marker `Python<'p>`, also a non
  trivial effort.

The main (and seemingly only) caller of this method being
`mercurial.setdiscovery`, which is currently undergoing serious refactoring,
it's not clear whether these improvements would be worth the effort right now,
so we're leaving it as-is.

Also, in `get_bases()` (will also be used by `setdiscovery`), we'd prefer
to build a Python set directly, but we resort to returning a tuple, waiting
to hear back from our PR onto rust-cpython about that

Differential Revision: https://phab.mercurial-scm.org/D5550

#!/usr/bin/env python
# Undump a dump from dumprevlog
# $ hg init
# $ undumprevlog < repo.dump

from __future__ import absolute_import, print_function

import sys
from mercurial import (
    encoding,
    node,
    pycompat,
    revlog,
    transaction,
    vfs as vfsmod,
)
from mercurial.utils import (
    procutil,
)

for fp in (sys.stdin, sys.stdout, sys.stderr):
    procutil.setbinary(fp)

opener = vfsmod.vfs(b'.', False)
tr = transaction.transaction(sys.stderr.write, opener, {b'store': opener},
                             b"undump.journal")
while True:
    l = sys.stdin.readline()
    if not l:
        break
    if l.startswith("file:"):
        f = encoding.strtolocal(l[6:-1])
        r = revlog.revlog(opener, f)
        pycompat.stdout.write(b'%s\n' % f)
    elif l.startswith("node:"):
        n = node.bin(l[6:-1])
    elif l.startswith("linkrev:"):
        lr = int(l[9:-1])
    elif l.startswith("parents:"):
        p = l[9:-1].split()
        p1 = node.bin(p[0])
        p2 = node.bin(p[1])
    elif l.startswith("length:"):
        length = int(l[8:-1])
        sys.stdin.readline() # start marker
        d = encoding.strtolocal(sys.stdin.read(length))
        sys.stdin.readline() # end marker
        r.addrevision(d, tr, lr, p1, p2)

tr.close()