scmutil: add option to register summary callbacks as transaction validators We have a list of summary callbacks which are run after the transaction is closed to show what has changed and what not. This patch makes it possible to register those callbacks as transaction validators so that we can show summary before committing the transaction and prompt user to accept the changes. The goal of this is to implement `pull --confirm`. Differential Revision: https://phab.mercurial-scm.org/D8199

transaction: add functionality to have multiple validators This will help us in adding more validators which can aggregate data from transaction and prompt user whether to commit the transaction or not. The current target is to use this to implement `pull --confirm`. Differential Revision: https://phab.mercurial-scm.org/D8198

hgit: make sure repository is local before checking for store type httppeer (and maybe others too) does not have a store attribute. This was causing `hg pull` being broken on a hg repository when the extension is enabled. localpeer.local() does returns a non-None value but I am not sure if it matters. Differential Revision: https://phab.mercurial-scm.org/D8217

hg-core: add function timing information This change makes use of the newly added logging infrastructure to trace the execution time of some important calls. This approach is very much complementary to using a profiler and will not guard against out-of-order execution or other kinds of compiler optimizations. That said, it is useful to get a rough high-level idea of where time is spent. Differential Revision: https://phab.mercurial-scm.org/D8253

rust: add logging utils This change adds the `log` crate, the community-approved logging facade backed by Rust core developers as well as the logging-consumer crate `simple_logger` to build a foundation for logging from Rust. Using this setup allows us to choose how to log depending on the way `hg-core` is used: if it's within the context of `hg-cpython`, we might not want to use it the same way as with a direct cli for example. Differential Revision: https://phab.mercurial-scm.org/D8252

rust-status: traverse working directory in parallel Using `rayon` for this task ensures that we are using the same work-stealing threadpool for everything. This change introduces `crossbeam` as an explicit dependency, although it is already a dependency of `rayon`. It provides better structures for multi-threaded tasks than the stdlib. Differential Revision: https://phab.mercurial-scm.org/D8251

rust-status: wrap `stat_dmap_entries` to ease profiling Differential Revision: https://phab.mercurial-scm.org/D8250

rust-status: refactor handling of unknown files Differential Revision: https://phab.mercurial-scm.org/D8249

rust-status: move to recursive traversal to prepare for parallel traversal I have looked into traversing the working directory in parallel either by a recursive or an iterative algorithm. The recursive approach won quite decisively both in terms of performance and code readability. You can look at my experiment here: https://heptapod.octobus.net/Alphare/rayon-recursive-traversal The chance of a stack overflow happening because the directories get too nested seems slim. This change does not yet do anything in parallel. Differential Revision: https://phab.mercurial-scm.org/D8215

rust-pathauditor: use interior mutability for use in multi-threaded contexts The usual recommendation for using `RwLock` or `Mutex` is that if there are about as many write as there are reads, use `Mutex`, and if there are more reads than writes, use `RwLock`. If after the main bottleneck (i.e. parallel traversal) is removed this shows up on profiles, we should investigate using the `parking_lot` since we don't need a poisoning API, or maybe move to different types of caches entirely. Differential Revision: https://phab.mercurial-scm.org/D8213