feat: Improve prediction integration

src/client.rs

@@ -88,8 +88,22 @@ impl Client {
         self.entered = false;
     }
 
-    pub fn move_by_delta(
+    pub fn move_self(&mut self, _point: isize) -> Option<String> {
+        self.move_by_delta(true, _point, 0, None)
+    }
+
+    pub fn move_other(
+        &mut self,
+        _point: isize,
+        _delta: isize,
+        _filename: Option<String>,
+    ) -> Option<String> {
+        self.move_by_delta(false, _point, _delta, _filename)
+    }
+
+    fn move_by_delta(
         &mut self,
+        _sender_p: bool,
         _point: isize,
         _delta: isize,
         _filename: Option<String>,
@@ -119,7 +133,7 @@ impl Client {
             }
         }
 
-        user.move_by_delta(_point, _delta);
+        user.move_by_delta(_sender_p, _point, _delta);
 
         Some(filename)
     }

src/handler/buffer.rs

@@ -25,7 +25,7 @@ pub mod update {
     fn predict_movement(addr: &SocketAddr, room: &mut Room, point: isize, delta: isize) {
         let client = room.get_client_mut(addr).unwrap();
 
-        let filename = client.move_by_delta(point, delta, None);
+        let filename = client.move_self(point);
 
         let clients = room.get_clients_mut();
 
@@ -34,7 +34,7 @@ pub mod update {
                 continue;
             }
 
-            _client.move_by_delta(point, delta, filename.clone());
+            _client.move_other(point, delta, filename.clone());
         }
     }
 
@@ -50,18 +50,20 @@ pub mod update {
 
         // Predict movement.
         {
-            let delta = if add_or_delete == "delete" {
-                beg - end
-            } else {
-                end - beg
-            };
+            let is_delete = add_or_delete == "delete";
+
+            // Predict the movement shift.
+            let delta = if is_delete { beg - end } else { end - beg };
+
+            // Predict the cursor final position.
+            let start = if is_delete { beg } else { end };
 
             // Nothing has changed; return it.
             if delta == 0 {
                 return;
             }
 
-            predict_movement(&addr, &mut room, beg, delta);
+            predict_movement(&addr, &mut room, start, delta);
         }
 
         // Update the buffer view.

src/user.rs

@@ -61,9 +61,10 @@ impl User {
     ///
     /// # Arguments
     ///
+    /// * `_sender` - Boolean return true if the user is the sender.
     /// * `_point` - Only effect point after the origin.
     /// * `_delta` - Movement delta.
-    pub fn move_by_delta(&mut self, _point: isize, _delta: isize) {
+    pub fn move_by_delta(&mut self, _sender: bool, _point: isize, _delta: isize) {
         // Point must exists.
         if self.point.is_none() {
             return;
@@ -73,16 +74,18 @@ impl User {
 
         // Shift the point.
         if _point <= point {
-            self.point = Some(point + _delta);
+            self.point = Some(if _sender { point } else { point + _delta });
 
             // `region_beg`. and `region_end` must exists at the same time.
             if !self.region_beg.is_none() {
                 let region_beg = self.region_beg.unwrap();
                 let region_end = self.region_end.unwrap();
 
                 // Shift the region.
-                self.region_beg = Some(region_beg + _delta);
-                self.region_end = Some(region_end + _delta);
+                //
+                // If the sender, just set to the point.
+                self.region_beg = Some(if _sender { point } else { region_beg + _delta });
+                self.region_end = Some(if _sender { point } else { region_end + _delta });
             }
         }
     }