Starts synchronous block interface

oxydsp-flowgraph/src/tag.rs

@@ -17,7 +17,51 @@ pub struct Tag
     // TODO: Make it such that when a tag is duplicated, the data seems to be too:
     // When adding on a duplicate, it should not replicate on others, but without
     // requiring a deep copy.
-    pub data: Arc<Mutex<HashMap<String, Box<dyn Any>>>>,
+    pub data: Arc<Mutex<HashMap<String, Arc<dyn Any + Send + Sync>>>>,
+}
+
+pub trait TagValue: Clone {}
+impl<T> TagValue for T where T: Clone {}
+
+pub trait TagMergable<T>
+{
+    fn merge(&self, other: &T) -> Self;
+}
+
+impl TagMergable<Tag> for Tag
+{
+    fn merge(&self, other: &Self) -> Self
+    {
+        // TODO: More performant merge
+        let mut new = other.clone();
+
+        new.position = self.position;
+        {
+            let mut data_locked = new.data.lock().unwrap();
+            for (k, v) in self.data.lock().unwrap().iter()
+            {
+                data_locked.insert(k.clone(), v.clone());
+            }
+        }
+
+        new
+    }
+}
+
+impl TagMergable<Option<Tag>> for Option<Tag>
+{
+    fn merge(&self, other: &Self) -> Self
+    {
+        match self
+        {
+            Some(first) => match other
+            {
+                Some(other) => Some(first.merge(other)),
+                None => Some(first.clone()),
+            },
+            None => other.clone(),
+        }
+    }
 }
 
 /// Represents a data, with a potential tag attached to it.