introduce WeakSignal

src/port/mod.rs

@@ -6,15 +6,13 @@ mod pport;
 
 pub(crate) use self::portconnector::PortConnector;
 
-use std::sync::Weak;
-
-use crate::Signal;
+use crate::signal::WeakSignal;
 
 pub use self::portdirection::{Dir, InOut, Input, MaybeRead, MaybeWrite, Off, Output, PortDirection, Read, Write};
 pub use self::pport::Port;
 
 #[derive(Debug)]
 pub(crate) struct InnerPort<T> {
     value: RwLock<T>,
-    signal: Weak<Signal<T>>,
+    signal: WeakSignal<T>,
 }

src/port/pport.rs

@@ -7,8 +7,8 @@ use super::InnerPort;
 use crate::direction::{Dir, InOut, Input, MaybeRead, MaybeWrite, Output, PortDirection, Read, Write};
 use crate::dump::IterValues;
 use crate::port::portconnector::PortConnector;
+use crate::signal::WeakSignal;
 use crate::Ieee1164;
-use std::sync::Weak;
 
 #[allow(unused)]
 use crate::{models::gates::AndGate, Signal};
@@ -70,7 +70,7 @@ impl<T, D: PortDirection> Port<T, D> {
         Port {
             inner: Arc::new(InnerPort {
                 value: RwLock::new(value),
-                signal: Weak::new(),
+                signal: WeakSignal::default(),
             }),
             _marker: PhantomData,
         }
@@ -110,7 +110,7 @@ where
     /// ```
     // FIXME!
     pub fn is_connected(&self) -> bool {
-        self.inner.signal.upgrade().is_some()
+        self.inner.signal.is_strong()
     }
 }
 

src/signal.rs

@@ -1,19 +1,33 @@
-use std::sync::{Arc, RwLock};
+use std::convert::TryInto;
+use std::sync::{Arc, RwLock, Weak};
 
+use crate::direction::{Input, Output, PortDirection};
 use crate::logicbit::Resolve;
-
-use crate::direction::{Input, Output};
-
 use crate::port::PortConnector;
-use crate::port::PortDirection;
 use crate::{Port, Updateable};
-use std::convert::TryInto;
 
 #[derive(Debug, Clone)]
 pub struct Signal<T> {
     inner: Arc<InnerSignal<T>>,
 }
 
+#[derive(Debug, Clone)]
+pub(crate) struct WeakSignal<T> {
+    inner: Weak<InnerSignal<T>>,
+}
+
+impl<T> Default for WeakSignal<T> {
+    fn default() -> Self {
+        WeakSignal { inner: Weak::new() }
+    }
+}
+
+impl<T> WeakSignal<T> {
+    pub(crate) fn is_strong(&self) -> bool {
+        self.inner.upgrade().is_some()
+    }
+}
+
 #[derive(Debug)]
 struct InnerSignal<T> {
     input_ports: RwLock<Vec<PortConnector<T, Input>>>,