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
cHg
===
A fast client for Mercurial command server running on Unix.
Install:
$ make
$ make install
Usage:
$ chg help # show help of Mercurial
$ alias hg=chg # replace hg command
$ chg --kill-chg-daemon # terminate background server
Environment variables:
Although cHg tries to update environment variables, some of them cannot be
changed after spawning the server. The following variables are specially
handled:
* configuration files are reloaded automatically by default.
* CHGHG or HG specifies the path to the hg executable spawned as the
background command server.
The following variables are available for testing:
* CHGDEBUG enables debug messages.
* CHGSOCKNAME specifies the socket path of the background cmdserver.
* CHGTIMEOUT specifies how many seconds chg will wait before giving up
connecting to a cmdserver. If it is 0, chg will wait forever. Default: 60
Build environment variables:
* HGPATH: the path to the hg executable to call when CHGHG and HG are not set,
instead of "hg"
* HGPATHREL=1: when CHGHG and HG are not set, the hg executable will be ./hg
relative to the chg executable. Only works on linux, falls back to "hg"
otherwise.