rust: add `Progress` trait for progress bars

This will be used in the next few changes to introduce a progress bar for
the `hg update` fastpath.

rust/hg-core/src/progress.rs

@@ -0,0 +1,11
+//! Progress-bar related things
+
+/// A generic determinate progress bar trait
+pub trait Progress: Send + Sync + 'static {
+    /// Set the current position and optionally the total
+    fn update(&self, pos: u64, total: Option<u64>);
+    /// Increment the current position and optionally the total
+    fn increment(&self, step: u64, total: Option<u64>);
+    /// Declare that progress is over and the progress bar should be deleted
+    fn complete(self);
+}

rust/hg-core/src/lib.rs

@@ -1,144 +1,145
 // Copyright 2018-2020 Georges Racinet <[e-mail]>
 //           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.
 
 mod ancestors;
 pub mod dagops;
 pub mod errors;
 pub mod narrow;
 pub mod sparse;
 pub use ancestors::{AncestorsIterator, MissingAncestors};
 pub mod dirstate;
 pub mod dirstate_tree;
 pub mod discovery;
 pub mod exit_codes;
 pub mod requirements;
 pub mod testing; // unconditionally built, for use from integration tests
 pub use dirstate::{
     dirs_multiset::{DirsMultiset, DirsMultisetIter},
     status::{
         BadMatch, BadType, DirstateStatus, HgPathCow, StatusError,
         StatusOptions,
     },
     DirstateEntry, DirstateParents, EntryState,
 };
 pub mod copy_tracing;
 pub mod filepatterns;
 pub mod matchers;
 pub mod repo;
 pub mod revlog;
 pub use revlog::*;
 pub mod checkexec;
 pub mod config;
 pub mod lock;
 pub mod logging;
 pub mod operations;
+pub mod progress;
 pub mod revset;
 pub mod utils;
 pub mod vfs;
 
 use crate::utils::hg_path::{HgPathBuf, HgPathError};
 pub use filepatterns::{
     parse_pattern_syntax_kind, read_pattern_file, IgnorePattern,
     PatternFileWarning, PatternSyntax,
 };
 use std::collections::HashMap;
 use std::fmt;
 use twox_hash::RandomXxHashBuilder64;
 
 pub type LineNumber = usize;
 
 /// Rust's default hasher is too slow because it tries to prevent collision
 /// attacks. We are not concerned about those: if an ill-minded person has
 /// write access to your repository, you have other issues.
 pub type FastHashMap<K, V> = HashMap<K, V, RandomXxHashBuilder64>;
 
 // TODO: should this be the default `FastHashMap` for all of hg-core, not just
 // dirstate_tree? How does XxHash compare with AHash, hashbrown’s default?
 pub type FastHashbrownMap<K, V> =
     hashbrown::HashMap<K, V, RandomXxHashBuilder64>;
 
 #[derive(Debug, PartialEq)]
 pub enum DirstateMapError {
     PathNotFound(HgPathBuf),
     InvalidPath(HgPathError),
 }
 
 impl From<HgPathError> for DirstateMapError {
     fn from(error: HgPathError) -> Self {
         Self::InvalidPath(error)
     }
 }
 
 impl fmt::Display for DirstateMapError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             DirstateMapError::PathNotFound(_) => {
                 f.write_str("expected a value, found none")
             }
             DirstateMapError::InvalidPath(path_error) => path_error.fmt(f),
         }
     }
 }
 
 #[derive(Debug, derive_more::From)]
 pub enum DirstateError {
     Map(DirstateMapError),
     Common(errors::HgError),
 }
 
 impl From<HgPathError> for DirstateError {
     fn from(error: HgPathError) -> Self {
         Self::Map(DirstateMapError::InvalidPath(error))
     }
 }
 
 impl fmt::Display for DirstateError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             DirstateError::Map(error) => error.fmt(f),
             DirstateError::Common(error) => error.fmt(f),
         }
     }
 }
 
 #[derive(Debug, derive_more::From)]
 pub enum PatternError {
     #[from]
     Path(HgPathError),
     UnsupportedSyntax(String),
     UnsupportedSyntaxInFile(String, String, usize),
     TooLong(usize),
     #[from]
     IO(std::io::Error),
     /// Needed a pattern that can be turned into a regex but got one that
     /// can't. This should only happen through programmer error.
     NonRegexPattern(IgnorePattern),
 }
 
 impl fmt::Display for PatternError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             PatternError::UnsupportedSyntax(syntax) => {
                 write!(f, "Unsupported syntax {}", syntax)
             }
             PatternError::UnsupportedSyntaxInFile(syntax, file_path, line) => {
                 write!(
                     f,
                     "{}:{}: unsupported syntax {}",
                     file_path, line, syntax
                 )
             }
             PatternError::TooLong(size) => {
                 write!(f, "matcher pattern is too long ({} bytes)", size)
             }
             PatternError::IO(error) => error.fmt(f),
             PatternError::Path(error) => error.fmt(f),
             PatternError::NonRegexPattern(pattern) => {
                 write!(f, "'{:?}' cannot be turned into a regex", pattern)
             }
         }
     }
 }