rust-matchers: use the `regex` crate
Instead of falling back to Python when a code path with "ignore" functionality
is reached and `Re2` is not installed, the default compilation (i.e. without
the `with-re2` feature) will use the `regex` crate for all regular expressions
business.
As with the introduction of `Re2` in a previous series, this yields a big
performance boost compared to the Python + C code in `status`, `diff`, `commit`,
`update`, and maybe others.
For now `Re2` looks to be faster at compiling the DFA (1.5ms vs 5ms for
Netbeans' `.hgignore`) and a bit faster in actual use: (123ms vs 137ms for
the parallel traversal of Netbeans' clean repo). I am in talks with the author
of `regex` to see whether that performance difference is a bug, a "won't fix",
or a tuning issue.
The `regex` crate is already one of our dependencies and using this code does
not require any additional work from the end-user than to use the Rust
extensions.
Differential Revision: https://phab.mercurial-scm.org/D8323
// Copyright 2018-2020 Georges Racinet <georges.racinet@octobus.net>
// and Mercurial contributors
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.
//! Mercurial concepts for handling revision history
pub mod node;
pub mod nodemap;
pub use node::{Node, NodeError, NodePrefix, NodePrefixRef};
/// Mercurial revision numbers
///
/// As noted in revlog.c, revision numbers are actually encoded in
/// 4 bytes, and are liberally converted to ints, whence the i32
pub type Revision = i32;
/// Marker expressing the absence of a parent
///
/// Independently of the actual representation, `NULL_REVISION` is guaranteed
/// to be smaller than all existing revisions.
pub const NULL_REVISION: Revision = -1;
/// Same as `mercurial.node.wdirrev`
///
/// This is also equal to `i32::max_value()`, but it's better to spell
/// it out explicitely, same as in `mercurial.node`
pub const WORKING_DIRECTORY_REVISION: Revision = 0x7fffffff;
/// The simplest expression of what we need of Mercurial DAGs.
pub trait Graph {
/// Return the two parents of the given `Revision`.
///
/// Each of the parents can be independently `NULL_REVISION`
fn parents(&self, rev: Revision) -> Result<[Revision; 2], GraphError>;
}
#[derive(Clone, Debug, PartialEq)]
pub enum GraphError {
ParentOutOfRange(Revision),
WorkingDirectoryUnsupported,
}
/// The Mercurial Revlog Index
///
/// This is currently limited to the minimal interface that is needed for
/// the [`nodemap`](nodemap/index.html) module
pub trait RevlogIndex {
/// Total number of Revisions referenced in this index
fn len(&self) -> usize;
/// Return a reference to the Node or `None` if rev is out of bounds
///
/// `NULL_REVISION` is not considered to be out of bounds.
fn node(&self, rev: Revision) -> Option<&Node>;
}