1 files changed, 24 insertions, 0 deletions
diff --git a/src/document/mod.rs b/src/document/mod.rs
index 1612145..2230e47 100644
--- a/src/document/mod.rs
+++ b/src/document/mod.rs
@@ -6,6 +6,30 @@
 /// Only `document` and `remake` use Automerge itself (`architecture.md`, The document).
 pub(crate) use automerge::{ActorId, AutoCommit as Document, Change, ChangeHash};
 
+/// The whole document as bytes, as the engine saves it: a backup, the document
+/// file's full save, the size a joining node downloads.
+pub(crate) fn save(doc: &mut Document) -> Vec<u8> {
+    doc.save()
+}
+
+/// The changes after `since` as bytes that, appended to a save, load with it (the
+/// document file's appends).
+pub(crate) fn save_since(doc: &mut Document, since: &[ChangeHash]) -> Vec<u8> {
+    doc.save_after(since)
+}
+
+/// A saved document (`save`), loaded to write to under a writer ID of its own: one ID
+/// must never write in two places, and a save may be loaded on several nodes, or again
+/// after the node that saved it wrote on.
+pub(crate) fn load(bytes: &[u8]) -> anyhow::Result<Document> {
+    Ok(Document::load(bytes)?.with_actor(ActorId::random()))
+}
+
+/// The actor (writer ID) `doc` writes under.
+pub(crate) fn actor(doc: &Document) -> ActorId {
+    doc.get_actor().clone()
+}
+
 pub(crate) mod changes;
 pub(crate) mod file;
 pub(crate) mod lock;