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
$ . $TESTDIR/wireprotohelpers.sh
$ hg init server
$ enablehttpv2 server
$ cd server
$ hg debugdrawdag << EOF
> C D
> |/
> B
> |
> A
> EOF
$ hg phase --public -r C
$ hg book -r C @
$ hg log -T '{rev}:{node} {desc}\n'
3:be0ef73c17ade3fc89dc41701eb9fc3a91b58282 D
2:26805aba1e600a82e93661149f2313866a221a7b C
1:112478962961147124edd43549aedd1a335e44bf B
0:426bada5c67598ca65036d57d9e4b64b0c1ce7a0 A
$ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
$ cat hg.pid > $DAEMON_PIDS
Request for namespaces works
$ sendhttpv2peer << EOF
> command listkeys
> namespace namespaces
> EOF
creating http peer for wire protocol version 2
sending listkeys command
response: {
b'bookmarks': b'',
b'namespaces': b'',
b'phases': b''
}
Request for phases works
$ sendhttpv2peer << EOF
> command listkeys
> namespace phases
> EOF
creating http peer for wire protocol version 2
sending listkeys command
response: {
b'be0ef73c17ade3fc89dc41701eb9fc3a91b58282': b'1',
b'publishing': b'True'
}
Request for bookmarks works
$ sendhttpv2peer << EOF
> command listkeys
> namespace bookmarks
> EOF
creating http peer for wire protocol version 2
sending listkeys command
response: {
b'@': b'26805aba1e600a82e93661149f2313866a221a7b'
}
$ cat error.log