dirstate-tree: Add tree traversal/iteration
Like Python’s, Rust’s iterators are "external" in that they are driven
by a caller who calls a `next` method. This is as opposed to "internal"
iterators who drive themselves and call a callback for each item.
Writing an internal iterator traversing a tree is easy with recursion,
but internal iterators cannot rely on the call stack in that way,
they must save in an explicit object all state that they need to be
preserved across two `next` calls.
This algorithm uses a `Vec` as a stack that contains what would be
local variables on the call stack if we could use recursion.
Differential Revision: https://phab.mercurial-scm.org/D10370
from __future__ import absolute_import
from mercurial.utils import procutil
# XXX: we should probably offer a devel option to do this in blackbox directly
def getuser():
return b'bob'
def getpid():
return 5000
# mock the date and user apis so the output is always the same
def uisetup(ui):
procutil.getuser = getuser
procutil.getpid = getpid