From bb5436d7e86dac449f3d2834854f4a5c68550027 Mon Sep 17 00:00:00 2001
From: Dingping Zhang <dingpingzhang@outlook.com>
Date: Tue, 16 Nov 2021 13:04:22 +0800
Subject: [PATCH] bugfix: ensure that execution events are synchronized. (#12)

---
 HandyIpc.Generator/ClientProxy.cs |  5 ++++-
 HandyIpc.Tests/EventTypeTest.cs   | 12 ++++++++----
 HandyIpc/Core/AwaiterManager.cs   | 15 +++++++++++----
 HandyIpc/Core/NotifierManager.cs  |  2 --
 4 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/HandyIpc.Generator/ClientProxy.cs b/HandyIpc.Generator/ClientProxy.cs
index 8b84ce9..a28eb3e 100644
--- a/HandyIpc.Generator/ClientProxy.cs
+++ b/HandyIpc.Generator/ClientProxy.cs
@@ -32,7 +32,9 @@ public class {nameof(ClientProxy)}{className}{typeParameters} : {interfaceType}
         private readonly string _key;
         private readonly AwaiterManager _awaiterManager;
 
-{events.For(item => $@"private event {item.Type.ToTypeDeclaration()} _{item.Name};")}
+{events.For(item => $@"
+        private event {item.Type.ToTypeDeclaration()} _{item.Name};
+")}
 
 {events.For(item =>
             {
@@ -63,6 +65,7 @@ public class {nameof(ClientProxy)}{className}{typeParameters} : {interfaceType}
                 }}
             }}
         }}
+
 ";
             })}
 
diff --git a/HandyIpc.Tests/EventTypeTest.cs b/HandyIpc.Tests/EventTypeTest.cs
index 8aa8e56..597eb3c 100644
--- a/HandyIpc.Tests/EventTypeTest.cs
+++ b/HandyIpc.Tests/EventTypeTest.cs
@@ -33,8 +33,12 @@ public void TestEventHandlerWithNamedPipe()
             TestEventHandlerSubscribeAndUnsubscribe(instance);
         }
 
-        private void TestEventHandlerSubscribeAndUnsubscribe(IEventType instance)
+        private static void TestEventHandlerSubscribeAndUnsubscribe(IEventType instance)
         {
+            // Some issues will occur only when the number of tests is high.
+            // In particular, it tests whether the event calls are synchronized.
+            const int testCount = 10000;
+
             int count1 = 0;
             int count2 = 0;
             int count3 = 0;
@@ -49,7 +53,7 @@ private void TestEventHandlerSubscribeAndUnsubscribe(IEventType instance)
             instance.Changed += handler2;
             instance.Changed += handler3;
 
-            for (int i = 0; i < 10; i++)
+            for (int i = 0; i < testCount; i++)
             {
                 instance.RaiseChanged(EventArgs.Empty);
                 Assert.Equal(i + 1, count1);
@@ -65,7 +69,7 @@ private void TestEventHandlerSubscribeAndUnsubscribe(IEventType instance)
             instance.Changed -= handler2;
             instance.Changed -= handler3;
 
-            for (int i = 0; i < 10; i++)
+            for (int i = 0; i < testCount; i++)
             {
                 instance.RaiseChanged(EventArgs.Empty);
                 Assert.Equal(0, count1);
@@ -79,7 +83,7 @@ private void TestEventHandlerSubscribeAndUnsubscribe(IEventType instance)
             instance.Changed += handler2;
             instance.Changed += handler3;
 
-            for (int i = 0; i < 10; i++)
+            for (int i = 0; i < testCount; i++)
             {
                 instance.RaiseChanged(EventArgs.Empty);
                 Assert.Equal(2 * (i + 1), count1);
diff --git a/HandyIpc/Core/AwaiterManager.cs b/HandyIpc/Core/AwaiterManager.cs
index 85c6519..72567c3 100644
--- a/HandyIpc/Core/AwaiterManager.cs
+++ b/HandyIpc/Core/AwaiterManager.cs
@@ -37,8 +37,7 @@ public void Unsubscribe(string name)
         {
             if (_pool.TryRemove(name, out _))
             {
-                using var rented = _sender.ConnectionPool.Rent();
-                byte[] removeResult = rented.Value.Invoke(Subscription.Remove(_key, name, _serializer));
+                byte[] removeResult = _sender.Invoke(Subscription.Remove(_key, name, _serializer));
                 if (!removeResult.IsUnit())
                 {
                     // TODO: Logging.
@@ -58,8 +57,16 @@ private static void LoopWait(Awaiter awaiter)
                     break;
                 }
 
-                connection.Write(Signals.Unit);
-                awaiter.Handler(input);
+                try
+                {
+                    // The Read() and Write() are used to ensure that calls are synchronized (blocked)
+                    // and that the Write() must be called after the execution of the Handler() is completed.
+                    awaiter.Handler(input);
+                }
+                finally
+                {
+                    connection.Write(Signals.Unit);
+                }
             }
         }
 
diff --git a/HandyIpc/Core/NotifierManager.cs b/HandyIpc/Core/NotifierManager.cs
index 85e38ec..144b6c0 100644
--- a/HandyIpc/Core/NotifierManager.cs
+++ b/HandyIpc/Core/NotifierManager.cs
@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 
 namespace HandyIpc.Core
@@ -6,7 +5,6 @@ namespace HandyIpc.Core
     public class NotifierManager
     {
         private readonly object _locker = new();
-        private readonly string _key = Guid.NewGuid().ToString();
         private readonly ISerializer _serializer;
         private readonly Dictionary<string, Notifier> _notifiers = new();