refactor: rewrite the way to register git command log receiver

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/Models/ICommandLog.cs

@@ -1,5 +1,10 @@
 namespace SourceGit.Models
 {
+    public interface ICommandLogReceiver
+    {
+        void OnReceiveCommandLog(string line);
+    }
+
     public interface ICommandLog
     {
         void AppendLine(string line);

src/ViewModels/CommandLog.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Text;
 using Avalonia.Threading;
 using CommunityToolkit.Mvvm.ComponentModel;
@@ -43,10 +44,14 @@ public CommandLog(string name)
             Name = name;
         }
 
-        public void Register(Action<string> handler)
+        public void Subscribe(Models.ICommandLogReceiver receiver)
         {
-            if (!IsComplete)
-                _onNewLineReceived += handler;
+            _receivers.Add(receiver);
+        }
+
+        public void Unsubscribe(Models.ICommandLogReceiver receiver)
+        {
+            _receivers.Remove(receiver);
         }
 
         public void AppendLine(string line = null)
@@ -59,7 +64,9 @@ public void AppendLine(string line = null)
             {
                 var newline = line ?? string.Empty;
                 _builder.AppendLine(newline);
-                _onNewLineReceived?.Invoke(newline);
+
+                foreach (var receiver in _receivers)
+                    receiver.OnReceiveCommandLog(newline);
             }
         }
 
@@ -76,20 +83,14 @@ public void Complete()
 
             _content = _builder.ToString();
             _builder.Clear();
+            _receivers.Clear();
             _builder = null;
 
             OnPropertyChanged(nameof(IsComplete));
-
-            if (_onNewLineReceived != null)
-            {
-                var dumpHandlers = _onNewLineReceived.GetInvocationList();
-                foreach (var d in dumpHandlers)
-                    _onNewLineReceived -= (Action<string>)d;
-            }
         }
 
         private string _content = string.Empty;
         private StringBuilder _builder = new StringBuilder();
-        private event Action<string> _onNewLineReceived;
+        private List<Models.ICommandLogReceiver> _receivers = new List<Models.ICommandLogReceiver>();
     }
 }

src/ViewModels/LauncherPage.cs

@@ -110,7 +110,10 @@ public async void ProcessPopup()
                 {
                     var finished = await dump.Sure();
                     if (finished)
+                    {
+                        dump.Cleanup();
                         Popup = null;
+                    }
                 }
                 catch (Exception e)
                 {

src/ViewModels/Popup.cs

@@ -4,7 +4,7 @@
 
 namespace SourceGit.ViewModels
 {
-    public class Popup : ObservableValidator
+    public class Popup : ObservableValidator, Models.ICommandLogReceiver
     {
         public bool InProgress
         {
@@ -27,6 +27,18 @@ public bool Check()
             return !HasErrors;
         }
 
+        public void OnReceiveCommandLog(string data)
+        {
+            var desc = data.Trim();
+            if (!string.IsNullOrEmpty(desc))
+                ProgressDescription = desc;
+        }
+
+        public void Cleanup()
+        {
+            _log?.Unsubscribe(this);
+        }
+
         public virtual bool CanStartDirectly()
         {
             return true;
@@ -39,17 +51,12 @@ public virtual Task<bool> Sure()
 
         protected void Use(CommandLog log)
         {
-            log.Register(SetDescription);
-        }
-
-        private void SetDescription(string data)
-        {
-            var desc = data.Trim();
-            if (!string.IsNullOrEmpty(desc))
-                ProgressDescription = desc;
+            _log = log;
+            _log.Subscribe(this);
         }
 
         private bool _inProgress = false;
         private string _progressDescription = string.Empty;
+        private CommandLog _log = null;
     }
 }

src/Views/CommandLogContentPresenter.cs

@@ -14,7 +14,7 @@
 
 namespace SourceGit.Views
 {
-    public class CommandLogContentPresenter : TextEditor
+    public class CommandLogContentPresenter : TextEditor, Models.ICommandLogReceiver
     {
         public class LineStyleTransformer : DocumentColorizingTransformer
         {
@@ -95,6 +95,12 @@ public string PureText
             TextArea.TextView.Options.EnableEmailHyperlinks = false;
         }
 
+        public void OnReceiveCommandLog(string line)
+        {
+            AppendText("\n");
+            AppendText(line);
+        }
+
         protected override void OnLoaded(RoutedEventArgs e)
         {
             base.OnLoaded(e);
@@ -126,10 +132,13 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
 
             if (change.Property == LogProperty)
             {
-                if (change.NewValue is ViewModels.CommandLog log)
+                if (change.OldValue is ViewModels.CommandLog oldLog)
+                    oldLog.Unsubscribe(this);
+
+                if (change.NewValue is ViewModels.CommandLog newLog)
                 {
-                    Text = log.Content;
-                    log.Register(OnLogLineReceived);
+                    Text = newLog.Content;
+                    newLog.Subscribe(this);
                 }
                 else
                 {
@@ -143,12 +152,6 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
             }
         }
 
-        private void OnLogLineReceived(string newline)
-        {
-            AppendText("\n");
-            AppendText(newline);
-        }
-
         private TextMate.Installation _textMate = null;
     }
 }