1 files changed, 37 insertions, 0 deletions
diff --git a/src/remake/mod.rs b/src/remake/mod.rs
index 0895931..ca17956 100644
--- a/src/remake/mod.rs
+++ b/src/remake/mod.rs
@@ -7,6 +7,7 @@
 //! * `records`: the replicated remake records under `_continuum/remakes/<id>`.
 //! * `coordinator`: proposal, vote count and decision on the node that was asked.
 //! * `vote`: who votes, for which remake, and when a remake has its majority.
+//! * `content`: the new document of a `replace`/`import` remake, fetched by every voter.
 //! * `switch`: switching this node to a committed epoch (worker).
 //! * `catchup`: rejoining a newer epoch from peers (late, new or failed nodes), then
 //!   replaying or quarantining this node's own missing changes.
@@ -20,6 +21,7 @@
 
 mod api;
 mod catchup;
+mod content;
 mod coordinator;
 mod delta;
 mod kind;
@@ -68,6 +70,21 @@ pub(crate) trait Host: Clone + Send + Sync + 'static {
     /// alive recently enough, read from `doc`.
     fn electorate(&self, doc: &AutoCommit, now_ms: u64) -> Vec<String>;
 
+    /// Downloads a change from peers on the local epoch, in chunks from several at once,
+    /// checked against its hash.
+    fn fetch_change(
+        &self,
+        hash: automerge::ChangeHash,
+    ) -> impl Future<Output = anyhow::Result<automerge::Change>> + Send;
+
+    /// Downloads content by its BLAKE3 hash from peers on the local epoch, checked
+    /// against it.
+    fn fetch_content(&self, hash: [u8; 32])
+    -> impl Future<Output = anyhow::Result<Vec<u8>>> + Send;
+
+    /// Starts sync with every peer (e.g. after holding it back).
+    fn request_sync(&self);
+
     fn is_node_ready(&self) -> impl Future<Output = bool> + Send;
 
     /// Known (not forgotten) peers.
@@ -124,10 +141,30 @@ pub(crate) struct PeerSummary {
     pub(crate) id: String,
     /// Not dormant.
     pub(crate) active: bool,
+    /// Completed the handshake and belongs to our swarm. A peer that merely sent us
+    /// something (a node of another swarm on the same network, a stranger before
+    /// admission) is not one, and nothing it advertises is followed.
+    pub(crate) member: bool,
+    /// What it last said about being ready; None before it said anything.
+    pub(crate) ready: Option<bool>,
     /// The epoch the peer last advertised.
     pub(crate) epoch: Option<Epoch>,
 }
 
+impl PeerSummary {
+    /// A peer whose epoch can be followed and downloaded from: an active member that
+    /// holds the document it advertises. A rejoining peer advertises its target epoch
+    /// with an empty document and `ready: false`.
+    pub(crate) fn serves_epoch(&self, epoch: Epoch) -> bool {
+        self.serves() && self.epoch == Some(epoch)
+    }
+
+    /// An active, ready member.
+    pub(crate) fn serves(&self) -> bool {
+        self.active && self.member && self.ready == Some(true)
+    }
+}
+
 /// Admin routes. Merged into the authenticated part of the node's router.
 /// Largest remake request (bytes). The proposal carries the new document to every
 /// node in one sync message, which Mycelium must deliver within its deadline, so