tree changes had already

1 files changed, 7 insertions, 0 deletions

diff --git a/src/document/sync.rs b/src/document/sync.rs
index 44ad833..4a3fe5e 100644
--- a/src/document/sync.rs
+++ b/src/document/sync.rs
@@ -22,6 +22,13 @@ use crate::transport::SyncPayload;
 /// A sync message from a peer, decoded (`decode`), to apply (`SyncSession::receive`).
 pub(crate) struct Received(sync::Message);
 
+impl Received {
+    /// Whether it carries changes (it may carry only heads and what the peer needs).
+    pub(crate) fn carries_changes(&self) -> bool {
+        !self.0.changes.is_empty()
+    }
+}
+
 /// `payload` decoded. Before taking the document's lock: decoding a large message takes
 /// a while.
 pub(crate) fn decode(payload: &SyncPayload) -> anyhow::Result<Received> {