upstream/mercurial-mirror Files · rust/hg-core/src/dirstate.rs

rust: fix unsound `OwningDirstateMap`...

rust: fix unsound `OwningDirstateMap` As per the previous patch, `OwningDirstateMap` is unsound. Self-referential structs are difficult to implement correctly in Rust since the compiler is free to move structs around as much as it wants to. They are also very rarely needed in practice, so the state-of-the-art on how they should be done within the Rust rules is still a bit new. The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense) of declaring self-referential structs. It is getting a lot attention and was improved very quickly when soundness issues were found in the past: rather than relying on our own (limited) review circle, we might as well use the de-facto common crate to fix this problem. This will give us a much better chance of finding issues should any new ones be discovered as well as the benefit of fewer `unsafe` APIs of our own. I was starting to think about how I would present a safe API to the old struct but soon realized that the callback-based approach was already done in `ouroboros`, along with a lot more care towards refusing incorrect structs. In short: we don't return a mutable reference to the `DirstateMap` anymore, we expect users of its API to pass a `FnOnce` that takes the map as an argument. This allows our `OwningDirstateMap` to control the input and output lifetimes of the code that modifies it to prevent such issues. Changing to `ouroboros` meant changing every API with it, but it is relatively low churn in the end. It correctly identified the example buggy modification of `copy_map_insert` outlined in the previous patch as violating the borrow rules. Differential Revision: https://phab.mercurial-scm.org/D12429

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r48882:bf8837e3 default


                r49857:c9f44fc9

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             dirstate.rs
        
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        Raphaël Gomès
    
rust-parsers: switch to parse/pack_dirstate to mutate-on-loop...

              r42993
            
      // dirstate module

      //

      // Copyright 2019 Raphaël Gomès <rgomes@octobus.net>

      //

      // This software may be used and distributed according to the terms of the

      // GNU General Public License version 2 or any later version.

        Simon Sapin
    
dirstate-v2: Make more APIs fallible, returning Result...

              r48126
            
      use crate::dirstate_tree::on_disk::DirstateV2ParseError;

        Simon Sapin
    
rhg: Add support for dirstate-v2...

              r48165
            
      use crate::revlog::node::NULL_NODE;

        Simon Sapin
    
rust: Make `DirstateParents`’s fields typed `Node`s...

              r47337
            
      use crate::revlog::Node;

        Simon Sapin
    
dirstate: Remove the flat Rust DirstateMap implementation...

              r48882
            
      use crate::utils::hg_path::HgPath;

        Simon Sapin
    
rust: Move DirstateEntry to its own module...

              r48830
            
      use bytes_cast::BytesCast;

        Raphaël Gomès
    
rust-parsers: switch to parse/pack_dirstate to mutate-on-loop...

              r42993
            
        Raphaël Gomès
    
rust: switch hg-core and hg-cpython to rust 2018 edition...

              r42828
            
      pub mod dirs_multiset;

        Simon Sapin
    
rust: Move DirstateEntry to its own module...

              r48830
            
      pub mod entry;

        Raphaël Gomès
    
rust: switch hg-core and hg-cpython to rust 2018 edition...

              r42828
            
      pub mod parsers;

        Raphaël Gomès
    
rust-dirstate-status: add first Rust implementation of `dirstate.status`...

              r43565
            
      pub mod status;

        Raphaël Gomès
    
rust: switch hg-core and hg-cpython to rust 2018 edition...

              r42828
            
        Simon Sapin
    
rust: Move DirstateEntry to its own module...

              r48830
            
      pub use self::entry::*;

        Simon Sapin
    
rust: Add Repo::dirstate_map and use it in `rhg status`...

              r48768
            
      #[derive(Debug, PartialEq, Copy, Clone, BytesCast)]

        Simon Sapin
    
rust: Rewrite dirstate parsing usin the `bytes-cast` crate...

              r47336
            
      #[repr(C)]

        Raphaël Gomès
    
rust-parsers: switch to parse/pack_dirstate to mutate-on-loop...

              r42993
            
      pub struct DirstateParents {

        Simon Sapin
    
rust: Make `DirstateParents`’s fields typed `Node`s...

              r47337
            
          pub p1: Node,

          pub p2: Node,

        Raphaël Gomès
    
rust: switch hg-core and hg-cpython to rust 2018 edition...

              r42828
            
      }

        Simon Sapin
    
rhg: Add support for dirstate-v2...

              r48165
            
      impl DirstateParents {

          pub const NULL: Self = Self {

              p1: NULL_NODE,

              p2: NULL_NODE,

          };

      }

        Simon Sapin
    
dirstate-v2: Make more APIs fallible, returning Result...

              r48126
            
      pub type StateMapIter<'a> = Box<

          dyn Iterator<

                  Item = Result<(&'a HgPath, DirstateEntry), DirstateV2ParseError>,

              > + Send

              + 'a,

      >;

        Raphaël Gomès
    
rust: start plugging the dirstate tree behind a feature gate...

              r46185
            
        Simon Sapin
    
dirstate-v2: Make more APIs fallible, returning Result...

              r48126
            
      pub type CopyMapIter<'a> = Box<

          dyn Iterator<Item = Result<(&'a HgPath, &'a HgPath), DirstateV2ParseError>>

              + Send

              + 'a,

      >;

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Raphaël Gomès rust-parsers: switch to parse/pack_dirstate to mutate-on-loop...	r42993	// dirstate module
		//
		// Copyright 2019 Raphaël Gomès <rgomes@octobus.net>
		//
		// This software may be used and distributed according to the terms of the
		// GNU General Public License version 2 or any later version.

Simon Sapin dirstate-v2: Make more APIs fallible, returning Result...	r48126	use crate::dirstate_tree::on_disk::DirstateV2ParseError;
Simon Sapin rhg: Add support for dirstate-v2...	r48165	use crate::revlog::node::NULL_NODE;
Simon Sapin rust: Make `DirstateParents`’s fields typed `Node`s...	r47337	use crate::revlog::Node;
Simon Sapin dirstate: Remove the flat Rust DirstateMap implementation...	r48882	use crate::utils::hg_path::HgPath;
Simon Sapin rust: Move DirstateEntry to its own module...	r48830	use bytes_cast::BytesCast;
Raphaël Gomès rust-parsers: switch to parse/pack_dirstate to mutate-on-loop...	r42993
Raphaël Gomès rust: switch hg-core and hg-cpython to rust 2018 edition...	r42828	pub mod dirs_multiset;
Simon Sapin rust: Move DirstateEntry to its own module...	r48830	pub mod entry;
Raphaël Gomès rust: switch hg-core and hg-cpython to rust 2018 edition...	r42828	pub mod parsers;
Raphaël Gomès rust-dirstate-status: add first Rust implementation of `dirstate.status`...	r43565	pub mod status;
Raphaël Gomès rust: switch hg-core and hg-cpython to rust 2018 edition...	r42828
Simon Sapin rust: Move DirstateEntry to its own module...	r48830	pub use self::entry::*;

Simon Sapin rust: Add Repo::dirstate_map and use it in `rhg status`...	r48768	#[derive(Debug, PartialEq, Copy, Clone, BytesCast)]
Simon Sapin rust: Rewrite dirstate parsing usin the `bytes-cast` crate...	r47336	#[repr(C)]
Raphaël Gomès rust-parsers: switch to parse/pack_dirstate to mutate-on-loop...	r42993	pub struct DirstateParents {
Simon Sapin rust: Make `DirstateParents`’s fields typed `Node`s...	r47337	pub p1: Node,
		pub p2: Node,
Raphaël Gomès rust: switch hg-core and hg-cpython to rust 2018 edition...	r42828	}

Simon Sapin rhg: Add support for dirstate-v2...	r48165	impl DirstateParents {
		pub const NULL: Self = Self {
		p1: NULL_NODE,
		p2: NULL_NODE,
		};
		}

Simon Sapin dirstate-v2: Make more APIs fallible, returning Result...	r48126	pub type StateMapIter<'a> = Box<
		dyn Iterator<
		Item = Result<(&'a HgPath, DirstateEntry), DirstateV2ParseError>,
		> + Send
		+ 'a,
		>;
Raphaël Gomès rust: start plugging the dirstate tree behind a feature gate...	r46185
Simon Sapin dirstate-v2: Make more APIs fallible, returning Result...	r48126	pub type CopyMapIter<'a> = Box<
		dyn Iterator<Item = Result<(&'a HgPath, &'a HgPath), DirstateV2ParseError>>
		+ Send
		+ 'a,
		>;