3 files changed, 54 insertions, 20 deletions
diff --git a/src/util/crdt/lww.rs b/src/util/crdt/lww.rs
index bc686e05..99bd8e7c 100644
--- a/src/util/crdt/lww.rs
+++ b/src/util/crdt/lww.rs
@@ -61,7 +61,7 @@ where
 	///
 	/// Compared to new, the CRDT's timestamp is not set to now
 	/// but must be set to the previous, non-compatible, CRDT's timestamp.
-	pub fn migrate_from_raw(ts: u64, value: T) -> Self {
+	pub fn raw(ts: u64, value: T) -> Self {
 		Self { ts, v: value }
 	}
 
@@ -77,6 +77,11 @@ where
 		self.v = new_value;
 	}
 
+	/// Get the timestamp currently associated with the value
+	pub fn timestamp(&self) -> u64 {
+		self.ts
+	}
+
 	/// Get the CRDT value
 	pub fn get(&self) -> &T {
 		&self.v
diff --git a/src/util/crdt/lww_map.rs b/src/util/crdt/lww_map.rs
index 21cb6e12..f3a90591 100644
--- a/src/util/crdt/lww_map.rs
+++ b/src/util/crdt/lww_map.rs
@@ -37,11 +37,12 @@ where
 	pub fn new() -> Self {
 		Self { vals: vec![] }
 	}
+
 	/// Used to migrate from a map defined in an incompatible format. This produces
 	/// a map that contains a single item with the specified timestamp (copied from
 	/// the incompatible format). Do this as many times as you have items to migrate,
 	/// and put them all together using the CRDT merge operator.
-	pub fn migrate_from_raw_item(k: K, ts: u64, v: V) -> Self {
+	pub fn raw_item(k: K, ts: u64, v: V) -> Self {
 		Self {
 			vals: vec![(k, ts, v)],
 		}
@@ -74,9 +75,37 @@ where
 		Self { vals: new_vals }
 	}
 
+	/// Updates a value in place in the map (this generates
+	/// a new timestamp)
 	pub fn update_in_place(&mut self, k: K, new_v: V) {
 		self.merge(&self.update_mutator(k, new_v));
 	}
+
+	/// Updates a value in place in the map, from a
+	/// (key, timestamp, value) triple, only if the given
+	/// timestamp is larger than the timestamp currently
+	/// in the map
+	pub fn merge_raw(&mut self, k: &K, ts2: u64, v2: &V) {
+		match self.vals.binary_search_by(|(k2, _, _)| k2.cmp(k)) {
+			Ok(i) => {
+				let (_, ts1, _v1) = &self.vals[i];
+				match ts2.cmp(ts1) {
+					Ordering::Greater => {
+						self.vals[i].1 = ts2;
+						self.vals[i].2 = v2.clone();
+					}
+					Ordering::Equal => {
+						self.vals[i].2.merge(v2);
+					}
+					Ordering::Less => (),
+				}
+			}
+			Err(i) => {
+				self.vals.insert(i, (k.clone(), ts2, v2.clone()));
+			}
+		}
+	}
+
 	/// Takes all of the values of the map and returns them. The current map is reset to the
 	/// empty map. This is very usefull to produce in-place a new map that contains only a delta
 	/// that modifies a certain value:
@@ -103,10 +132,12 @@ where
 		let vals = std::mem::take(&mut self.vals);
 		Self { vals }
 	}
+
 	/// Removes all values from the map
 	pub fn clear(&mut self) {
 		self.vals.clear();
 	}
+
 	/// Get a reference to the value assigned to a key
 	pub fn get(&self, k: &K) -> Option<&V> {
 		match self.vals.binary_search_by(|(k2, _, _)| k2.cmp(k)) {
@@ -114,6 +145,16 @@ where
 			Err(_) => None,
 		}
 	}
+
+	/// Get the timestamp of the value assigned to a key, or 0 if
+	/// no value is assigned
+	pub fn get_timestamp(&self, k: &K) -> u64 {
+		match self.vals.binary_search_by(|(k2, _, _)| k2.cmp(k)) {
+			Ok(i) => self.vals[i].1,
+			Err(_) => 0,
+		}
+	}
+
 	/// Gets a reference to all of the items, as a slice. Usefull to iterate on all map values.
 	/// In most case you will want to ignore the timestamp (second item of the tuple).
 	pub fn items(&self) -> &[(K, u64, V)] {
@@ -138,24 +179,7 @@ where
 {
 	fn merge(&mut self, other: &Self) {
 		for (k, ts2, v2) in other.vals.iter() {
-			match self.vals.binary_search_by(|(k2, _, _)| k2.cmp(k)) {
-				Ok(i) => {
-					let (_, ts1, _v1) = &self.vals[i];
-					match ts2.cmp(ts1) {
-						Ordering::Greater => {
-							self.vals[i].1 = *ts2;
-							self.vals[i].2 = v2.clone();
-						}
-						Ordering::Equal => {
-							self.vals[i].2.merge(v2);
-						}
-						Ordering::Less => (),
-					}
-				}
-				Err(i) => {
-					self.vals.insert(i, (k.clone(), *ts2, v2.clone()));
-				}
-			}
+			self.merge_raw(k, *ts2, v2);
 		}
 	}
 }
diff --git a/src/util/time.rs b/src/util/time.rs
index d9192443..257b4d2a 100644
--- a/src/util/time.rs
+++ b/src/util/time.rs
@@ -15,6 +15,11 @@ pub fn increment_logical_clock(prev: u64) -> u64 {
 	std::cmp::max(prev + 1, now_msec())
 }
 
+/// Increment two logical clocks
+pub fn increment_logical_clock_2(prev: u64, prev2: u64) -> u64 {
+	std::cmp::max(prev2 + 1, std::cmp::max(prev + 1, now_msec()))
+}
+
 /// Convert a timestamp represented as milliseconds since UNIX Epoch to
 /// its RFC3339 representation, such as "2021-01-01T12:30:00Z"
 pub fn msec_to_rfc3339(msecs: u64) -> String {