Crate git_repository

This crate provides the Repository abstraction which serves as a hub into all the functionality of git.

It’s powerful and won’t sacrifice performance while still increasing convenience compared to using the sub-crates individually. Sometimes it may hide complexity under the assumption that the performance difference doesn’t matter for all but the fewest tools out there, which would be using the underlying crates directly or file an issue.

The prelude and extensions

With use git_repository::prelude::* you should be ready to go as it pulls in various extension traits to make functionality available on objects that may use it.

The method signatures are still complex and may require various arguments for configuration and cache control.

Easy-Mode

Most extensions to existing objects provide an obj_with_extension.easy(&repo).an_easier_version_of_a_method() or easy(&repo) method to hide all complex arguments and sacrifice some performance for a lot of convenience.

When starting out, use easy(…) and migrate to the more detailed method signatures to squeeze out more performance.

Design Sketch

Goal is to make the lower-level plumbing available without having to deal with any caches or buffers, and avoid any allocation beyond sizing the buffer to fit the biggest object seen so far.

• no implicit object lookups, thus Oid needs to get an Object first to start out with data via object()
• Objects with Ref suffix can only exist one at a time unless they are transformed into an owned version of it OR multiple Easy handles are present, each providing another ‘slot’ for an object as long as its retrieved through the respective Easy object.
• ObjectRef blocks the current buffer, hence many of its operations that use the buffer are consuming
• All methods that access a any field from Easy’s mutable State are fallible, and return easy::Result<_> at least, to avoid panics if the field can’t be referenced due to borrow rules of RefCell.
• Anything attached to Access can be detached to lift the object limit or make them Send-able. They can be attached to another Access if needed.
• git-repository functions related to Access extensions will always return attached versions of return values, like Oid instead of ObjectId, ObjectRef instead of git_odb::data::Object, or Reference instead of git_ref::file::Reference.
• Obtaining mutable is currently a weak spot as these only work with Arc right now and can’t work with Rc<RefCell> due to missing GATs, presumably. All Easy*!Exclusive types are unable to provide a mutable reference to the underlying repository. However, other ways to adjust the Repository of long-running applications are possible. For instance, there could be a flag that indicates a new Repository should be created (for instance, after it was changed) which causes the next server connection to create a new one. This instance is the one to use when spawning new EasyArc instances.

Limitations

• types containing &impl Access can’t access extension traits directly but have to use a workaround. This is due to the way extension traits can’t apply internally if if it is implemented, but must be part of the external interface. This is only relevant for code within git-repository

Cargo-features

With the optional “unstable” cargo feature

To make using sub-crates easier these are re-exported into the root of this crate. Note that these may change their major version even if this crate doesn’t, hence breaking downstream.

git_repository::

• hash
• [url]
• actor
• [objs]
  • [bstr][objs::bstr]
• [odb]
  • [pack][odb::pack]
• refs
• interrupt
• [tempfile]
• [lock]
• [traverse]
• [diff]
• [parallel]
• [Progress]
• [progress]
• interrupt
• [protocol]
  • [transport][protocol::transport]

Re-exports

pub use git_actor as actor;

pub use git_hash as hash;

pub use git_ref as refs;

pub use path::Path;

Modules

easy

Which Easy* is for me?

init

interrupt

Process-global interrupt handling

path

prelude

repository

Structs

Easy

A handle to a Repository for use when the repository needs to be shared, providing state for one ObjectRef at a time, , created with Repository::into_easy().

EasyArc

A handle to a Repository for sharing across threads, with each thread having one or more caches, created with Repository::into_easy_arc()

EasyShared

A handle to a repository for use when the repository needs to be shared using an actual reference, providing state for one ObjectRef at a time, created with Repository::to_easy()

Repository

A instance with access to everything a git repository entails, best imagined as container for most for system resources required to interact with a git repository which are loaded in once the instance is created.

Enums

Kind

The kind of Repository

Functions

discover

See Repository::discover().