# Oxygen

Oxygen (`oxy`) is a distributed, commutative version control system written in Rust for large repositories. See [docs/spec.md](docs/spec.md) for the specification.

It is self-hosting: this directory is an Oxygen repository, and the project's own history is kept with `oxy`, not with Git.

## What is different

- **History is a set of changes, not a chain of snapshots.** A change records what it did to identified lines and tree nodes and which earlier changes it depends on. Changes that do not depend on each other commute, so there are no merge commits and rebasing independent work rewrites nothing.

- **Conflicts are data.** A conflicted state can be committed, pushed and pulled. Resolving one is an ordinary edit followed by a commit.

- **Every change has a stable ID and a content hash.** The ID survives rewrites; the hash makes history tamper-evident.

- **Everything is signed.** Composite Ed25519 + ML-DSA-65 signatures on changes and on every bookmark update, verified against a trust policy that lives in the repository.

- **Every operation is undoable** through an operation log.

- **Large files are chunked** with content-defined chunking into a BLAKE3-addressed store.

## Status

Early, but usable for its own development. Implemented: the object model, the change graph with conflict detection and resolution, the working copy (`status`, `commit`, `checkout`, `diff`, `undo`), identities and signatures, remotes over local paths and HTTP(S) with `clone`, `fetch`, `pull`, `push`, the reference server `oxy serve`, the trust policy, and packed storage.

Not yet: checkpoints for very long histories, history editing (`rebase`, `split`, `edit`), multiple workspaces, garbage collection with retention, and the Thin client profile for constrained machines.

## Install

Builds for Linux, macOS and Windows are on the [releases page](https://oxygenhub.io/andymccall/oxygen/releases). These are early releases: the macOS and Windows builds are not signed and have had little testing.

- **Debian, Ubuntu and other Linux with apt** (x86_64 or arm64): download `oxy_VERSION_amd64.deb` (or `_arm64.deb`) and run `sudo apt install ./oxy_VERSION_amd64.deb`. It needs glibc 2.28 or later (Debian 10, Ubuntu 20.04 and newer).

- **Other Linux:** unpack `oxy-VERSION-linux-x86_64.tar.gz` (or `-linux-arm64`) and put `oxy` on your `PATH`.

- **macOS** (Apple Silicon or Intel): unpack `oxy-VERSION-macos-arm64.tar.gz` (or `-macos-x86_64`), then `xattr -d com.apple.quarantine oxy`, since the build is not notarised, and put it on your `PATH`.

- **Windows:** unzip `oxy-VERSION-windows-x86_64.zip` and put the folder on your `PATH`. SmartScreen may warn on first run, since the build is not signed.

`oh`, the OxygenHub command line, is released the same way from [OxygenHub's releases](https://oxygenhub.io/andymccall/oxygenhub/releases).

Check a download against the release's `SHA256SUMS` with `sha256sum -c SHA256SUMS --ignore-missing`.

## Building

```

cargo build --release

cargo test --workspace

```

The binary is `target/release/oxy`.

## Quick start

```

oxy identity create --name "Your Name" --email [email protected]

oxy config --user core.sign change      # sign every commit

oxy init                                 # in a project directory

oxy status

oxy commit -m "First change"

oxy log

```

Collaborating:

```

oxy serve --root /srv/oxy --bind 0.0.0.0:8890 --tls-cert cert.pem --tls-key key.pem --token SECRET

oxy clone https://host:8890/project

oxy config remote.origin.token SECRET

oxy push

oxy pull

```

Trust policy, so a server accepts only changes from keys you have granted:

```

oxy policy init                          # your key becomes the root

oxy identity export                      # a contributor sends you this file

oxy policy grant alice.identity

oxy push                                 # publishes the policy

```

## Layout

| Path | Contents |

|---|---|

| `crates/oxy-core` | Library: encoding, hashing, objects, the change graph, storage, identities, policy, protocol, repository operations |

| `crates/oxy-server` | Reference HTTP(S) server for the wire protocol |

| `src/cli` | The `oxy` command-line interface |

| `docs/spec.md` | The specification |

## Licence

MIT or Apache-2.0, at your option (see `LICENSE`).