Data file handling

Src/Myc.Signals.pas

@@ -3,7 +3,8 @@ unit Myc.Signals;
 interface
 
 uses
-    System.SysUtils;
+    System.SysUtils,
+    System.SyncObjs;
 
 type
     TSignal = record
@@ -136,6 +137,8 @@ type
     strict private
         class var
             FNull: ILatch;
+            FQueueGate: TLatch;
+            FQueueLock: TSpinLock;
         class constructor ClassCreate;
 
     private
@@ -150,7 +153,8 @@ type
 
         class function CreateLatch(Count: Integer): TLatch; static;
 
-        class function Enqueue(var Gate: TLatch; Count: Integer = 1): TState; static;
+        class function Enqueue(var Gate: TLatch): TState; overload; static;
+        class function Enqueue: TState; overload; static;
 
         class property Null: ILatch read FNull;
 
@@ -390,6 +394,7 @@ class constructor TLatch.ClassCreate;
 begin
     // Create a singleton null latch instance that is initially (and always) set.
     FNull := TMycNullLatch.Create;
+    FQueueLock := TSpinLock.Create(false);
 end;
 
 constructor TLatch.Create(const ALatch: TLatch.ILatch);
@@ -407,12 +412,23 @@ begin
         Result := FNull;
 end;
 
-class function TLatch.Enqueue(var Gate: TLatch; Count: Integer = 1): TState;
+class function TLatch.Enqueue(var Gate: TLatch): TState;
 begin
-    var gateState := Gate.State;
-    Gate := TMycLatch.Create(Count);
-    gateState.Subscribe(Gate);
-    exit(Gate.State);
+    var Latch: TLatch.ILatch := TMycLatch.Create(1);
+
+    FQueueLock.Enter;
+    try
+        Gate.State.Subscribe(Latch);
+        Gate := Latch;
+        Result := Latch.State;
+    finally
+        FQueueLock.Exit;
+    end;
+end;
+
+class function TLatch.Enqueue: TState;
+begin
+    Result := Enqueue(FQueueGate);
 end;
 
 function TLatch.GetState: TState;