OXYGENHUB
# adec9a0796b8 oxygen / crates / oxy-core / src / protocol.rs
3.4 KiB · Rust · last changed Remotes: local transport, push with seals and reference attestations, fetch, pull as state union, clone 1 month ago source blame history raw
5b9c6ad4 Andy McCall ↶ 1 
//! Transport-agnostic protocol (spec §16): what a client asks of a remote and
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//! what a server does with a push. `LocalRemote` serves another repository
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//! directory in-process; an HTTPS transport implements the same trait and the
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//! server side reuses `Repo::receive_push` and friends unchanged.
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use crate::attest::Attest;
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use crate::hash::{ChangeHash, ObjectRef, ObjectType};
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use crate::identity::Signature;
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use crate::objects::Change;
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use crate::repo::{Repo, RepoError, Result};
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use std::path::Path;
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/// An attestation together with the signatures over its ObjectRef.
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#[derive(Clone, Debug, PartialEq, Eq)]
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pub struct SignedAttest {
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    pub attest: Attest,
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    pub sigs: Vec<Signature>,
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}
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/// One reference as a remote reports it.
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#[derive(Clone, Debug)]
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pub struct RemoteRef {
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    pub name: String,
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    pub state: ObjectRef,
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    pub heads: Vec<ChangeHash>,
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    pub attestation: Option<SignedAttest>,
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}
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/// Everything needed to add a set of changes to a repository.
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#[derive(Clone, Debug, Default)]
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pub struct Bundle {
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    /// In dependency order, each with its individual signatures.
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    pub changes: Vec<(Change, Vec<Signature>)>,
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    /// Seals covering the changes.
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    pub attests: Vec<SignedAttest>,
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    /// Chunks, blobs, identities, and state objects referenced by the changes.
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    pub objects: Vec<(ObjectType, Vec<u8>)>,
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}
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impl Bundle {
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    pub fn is_empty(&self) -> bool {
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        self.changes.is_empty() && self.attests.is_empty() && self.objects.is_empty()
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    }
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}
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/// A requested bookmark move (spec §10.2, §16.3).
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#[derive(Clone, Debug)]
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pub struct RefUpdate {
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    pub name: String,
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    pub old_state: ObjectRef,
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    pub new_state: ObjectRef,
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    pub force: bool,
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    pub attestation: Option<SignedAttest>,
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}
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#[derive(Clone, Debug, PartialEq, Eq)]
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pub struct RefResult {
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    pub name: String,
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    pub ok: bool,
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    pub reason: String,
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}
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pub trait Remote {
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    fn repo_id(&self) -> Result<[u8; 16]>;
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    fn refs(&self) -> Result<Vec<RemoteRef>>;
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    /// Changes in the closure of `want` but not of `have`, in dependency order.
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    fn negotiate(&self, have: &[ChangeHash], want: &[ChangeHash]) -> Result<Vec<ChangeHash>>;
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    fn fetch(&self, changes: &[ChangeHash]) -> Result<Bundle>;
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    fn push(&self, bundle: Bundle, updates: Vec<RefUpdate>) -> Result<Vec<RefResult>>;
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}
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/// Another repository on this machine, served in-process.
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pub struct LocalRemote {
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    pub repo: Repo,
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}
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impl LocalRemote {
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    pub fn open(path: &Path) -> Result<LocalRemote> {
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        Ok(LocalRemote { repo: Repo::open(path)? })
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    }
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}
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impl Remote for LocalRemote {
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    fn repo_id(&self) -> Result<[u8; 16]> {
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        self.repo.id()
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    }
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    fn refs(&self) -> Result<Vec<RemoteRef>> {
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        self.repo.remote_refs()
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    }
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    fn negotiate(&self, have: &[ChangeHash], want: &[ChangeHash]) -> Result<Vec<ChangeHash>> {
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        self.repo.negotiate(have, want)
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    }
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    fn fetch(&self, changes: &[ChangeHash]) -> Result<Bundle> {
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        self.repo.bundle_for(changes)
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    }
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    fn push(&self, bundle: Bundle, updates: Vec<RefUpdate>) -> Result<Vec<RefResult>> {
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        self.repo.receive_push(bundle, updates)
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    }
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}
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/// Open a remote by URL. Only local paths (optionally `file://`) exist so far.
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pub fn open_remote(url: &str) -> Result<Box<dyn Remote>> {
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    let path = url.strip_prefix("file://").unwrap_or(url);
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    if path.contains("://") {
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        return Err(RepoError::Msg(format!("unsupported remote URL {url:?}: only local paths are implemented")));
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    }
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    Ok(Box::new(LocalRemote::open(Path::new(path))?))
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}