From 28b75c25100ce9de48619f6f19af48d5f7ef133c Mon Sep 17 00:00:00 2001
From: Sour <mesenemu@gmail.com>
Date: Fri, 8 Nov 2024 15:45:32 +0900
Subject: [PATCH] UI: Fixed crashes that could occur when using undo after
 typing in a text box

---
 UI/App.axaml                                  |  2 ++
 UI/Controls/PathSelector.axaml                |  2 +-
 UI/Debugger/Views/QuickSearchView.axaml       |  2 +-
 .../Windows/BreakpointEditWindow.axaml        |  2 +-
 UI/Debugger/Windows/CommentEditWindow.axaml   |  2 +-
 .../Windows/FindAllOccurrencesWindow.axaml    |  2 +-
 UI/Debugger/Windows/GoToAllWindow.axaml       |  2 +-
 UI/Debugger/Windows/GoToWindow.axaml          |  2 +-
 UI/Debugger/Windows/LabelEditWindow.axaml     |  4 +--
 .../Windows/MemoryViewerFindWindow.axaml      |  2 +-
 UI/Debugger/Windows/TraceLoggerWindow.axaml   | 20 +++++++++++--
 UI/Styles/DebugStatusStyles.xaml              |  2 ++
 UI/Utilities/NullTextConverter.cs             | 30 +++++++++++++++++++
 UI/Windows/CheatDatabaseWindow.axaml          |  2 +-
 UI/Windows/CheatEditWindow.axaml              |  4 +--
 UI/Windows/InputBarcodeWindow.axaml           |  2 +-
 UI/Windows/MovieRecordWindow.axaml            |  4 +--
 UI/Windows/NetplayConnectWindow.axaml         |  6 ++--
 UI/Windows/NetplayStartServerWindow.axaml     |  4 +--
 UI/Windows/SelectRomWindow.axaml              |  2 +-
 20 files changed, 73 insertions(+), 25 deletions(-)
 create mode 100644 UI/Utilities/NullTextConverter.cs

diff --git a/UI/App.axaml b/UI/App.axaml
index 0241206f..8e02f3e9 100644
--- a/UI/App.axaml
+++ b/UI/App.axaml
@@ -31,6 +31,8 @@
 
 		<l:EnumConverter x:Key="Enum" />
 		<u:FontNameConverter x:Key="FontNameConverter" />
+		<u:NullTextConverter x:Key="NullTextConverter" />
+		
 		<VisualBrush x:Key="ViewerBgBrush" TileMode="Tile" Stretch="None" AlignmentX="Left" AlignmentY="Top" SourceRect="0,0,5,5" DestinationRect="0,0,5,5">
 			<VisualBrush.Visual>
 				<Panel Background="#202020">
diff --git a/UI/Controls/PathSelector.axaml b/UI/Controls/PathSelector.axaml
index 7103e8d6..42b43a2a 100644
--- a/UI/Controls/PathSelector.axaml
+++ b/UI/Controls/PathSelector.axaml
@@ -17,7 +17,7 @@
 		/>
 		<DockPanel IsVisible="{Binding Editable}">
 			<Button MinWidth="30" DockPanel.Dock="Right" Content="..." Click="btnBrowse_OnClick" />
-			<TextBox Text="{Binding Path}" />
+			<TextBox Text="{Binding Path, Converter={StaticResource NullTextConverter}}" />
 		</DockPanel>
 	</Panel>
 </UserControl>
\ No newline at end of file
diff --git a/UI/Debugger/Views/QuickSearchView.axaml b/UI/Debugger/Views/QuickSearchView.axaml
index 2cbbaae1..6b1ecc72 100644
--- a/UI/Debugger/Views/QuickSearchView.axaml
+++ b/UI/Debugger/Views/QuickSearchView.axaml
@@ -36,7 +36,7 @@
 			<TextBox
 				Name="txtSearch"
 				Width="120"
-				Text="{Binding SearchString}"
+				Text="{Binding SearchString, Converter={StaticResource NullTextConverter}}"
 				Classes.highlight="{Binding IsErrorVisible}"
 		  />
 			<c:IconButton Icon="Assets/PreviousArrow.png" Command="{Binding FindPrev}" />
diff --git a/UI/Debugger/Windows/BreakpointEditWindow.axaml b/UI/Debugger/Windows/BreakpointEditWindow.axaml
index ccffcc26..53b89a35 100644
--- a/UI/Debugger/Windows/BreakpointEditWindow.axaml
+++ b/UI/Debugger/Windows/BreakpointEditWindow.axaml
@@ -86,7 +86,7 @@
 					AcceptsReturn="True"
 					TextWrapping="Wrap"
 					Height="NaN"
-					Text="{Binding Breakpoint.Condition}"
+					Text="{Binding Breakpoint.Condition, Converter={StaticResource NullTextConverter}}"
 				/>
 
 				<Image Grid.Column="1" Stretch="None" Source="/Assets/Warning.png" ToolTip.Tip="{l:Translate lblConditionError}" IsVisible="{Binding !IsConditionValid}" />
diff --git a/UI/Debugger/Windows/CommentEditWindow.axaml b/UI/Debugger/Windows/CommentEditWindow.axaml
index b1bd4b9c..6f9c210b 100644
--- a/UI/Debugger/Windows/CommentEditWindow.axaml
+++ b/UI/Debugger/Windows/CommentEditWindow.axaml
@@ -36,7 +36,7 @@
 			MinHeight="21"
 			MaxHeight="200"
 			VerticalContentAlignment="Top"
-			Text="{Binding Label.Comment}"
+			Text="{Binding Label.Comment, Converter={StaticResource NullTextConverter}}"
 		/>
 	</DockPanel>
 </Window>
diff --git a/UI/Debugger/Windows/FindAllOccurrencesWindow.axaml b/UI/Debugger/Windows/FindAllOccurrencesWindow.axaml
index a4352996..defeeaf3 100644
--- a/UI/Debugger/Windows/FindAllOccurrencesWindow.axaml
+++ b/UI/Debugger/Windows/FindAllOccurrencesWindow.axaml
@@ -33,7 +33,7 @@
 				<TextBox
 					Name="txtSearch"
 					HorizontalAlignment="Stretch"
-					Text="{Binding SearchString, ElementName=root}"
+					Text="{Binding SearchString, ElementName=root, Converter={StaticResource NullTextConverter}}"
 				/>
 			</DockPanel>
 			<CheckBox IsChecked="{Binding MatchCase, ElementName=root}" Content="{l:Translate chkMatchCase}" />
diff --git a/UI/Debugger/Windows/GoToAllWindow.axaml b/UI/Debugger/Windows/GoToAllWindow.axaml
index ad6b34e0..ae90e35c 100644
--- a/UI/Debugger/Windows/GoToAllWindow.axaml
+++ b/UI/Debugger/Windows/GoToAllWindow.axaml
@@ -63,7 +63,7 @@
 				Grid.Column="1"
 				Name="txtSearch"
 				HorizontalAlignment="Stretch"
-				Text="{Binding SearchString}"
+				Text="{Binding SearchString, Converter={StaticResource NullTextConverter}}"
 				MaxLength="300"
 			/>
 		</Grid>
diff --git a/UI/Debugger/Windows/GoToWindow.axaml b/UI/Debugger/Windows/GoToWindow.axaml
index 580aaef9..b64bdecd 100644
--- a/UI/Debugger/Windows/GoToWindow.axaml
+++ b/UI/Debugger/Windows/GoToWindow.axaml
@@ -41,7 +41,7 @@
 			<TextBox
 				Name="txtAddress"
 				HorizontalAlignment="Stretch"
-				Text="{Binding Address, ElementName=root}"
+				Text="{Binding Address, ElementName=root, Converter={StaticResource NullTextConverter}}"
 			/>
 		</DockPanel>
 	</DockPanel>
diff --git a/UI/Debugger/Windows/LabelEditWindow.axaml b/UI/Debugger/Windows/LabelEditWindow.axaml
index d922d860..c5ead6f0 100644
--- a/UI/Debugger/Windows/LabelEditWindow.axaml
+++ b/UI/Debugger/Windows/LabelEditWindow.axaml
@@ -57,7 +57,7 @@
 			<TextBox
 				Grid.Column="1" Grid.Row="2"
 				Name="txtLabel"
-				Text="{Binding Label.Label}"
+				Text="{Binding Label.Label, Converter={StaticResource NullTextConverter}}"
 			/>
 
 			<TextBlock Grid.Column="0" Grid.Row="3" Text="{l:Translate lblComment}" />
@@ -68,7 +68,7 @@
 				Height="NaN"
 				MinHeight="100"
 				VerticalContentAlignment="Top"
-				Text="{Binding Label.Comment}"
+				Text="{Binding Label.Comment, Converter={StaticResource NullTextConverter}}"
 				FontFamily="{DynamicResource MesenMonospaceFont}"
 				FontSize="{DynamicResource MesenMonospaceFontSize}"
 			/>
diff --git a/UI/Debugger/Windows/MemoryViewerFindWindow.axaml b/UI/Debugger/Windows/MemoryViewerFindWindow.axaml
index 684e90fa..c0628ec5 100644
--- a/UI/Debugger/Windows/MemoryViewerFindWindow.axaml
+++ b/UI/Debugger/Windows/MemoryViewerFindWindow.axaml
@@ -75,7 +75,7 @@
 				ScrollViewer.VerticalScrollBarVisibility="Disabled"
 				Height="21"
 				MinHeight="21"
-				Text="{Binding SearchString}"
+				Text="{Binding SearchString, Converter={StaticResource NullTextConverter}}"
 				MaxLength="300"
 			/>
 			<Image
diff --git a/UI/Debugger/Windows/TraceLoggerWindow.axaml b/UI/Debugger/Windows/TraceLoggerWindow.axaml
index 9fb1b52f..fe6cf988 100644
--- a/UI/Debugger/Windows/TraceLoggerWindow.axaml
+++ b/UI/Debugger/Windows/TraceLoggerWindow.axaml
@@ -114,8 +114,19 @@
 
 							<Grid ColumnDefinitions="Auto,*,Auto" RowDefinitions="Auto,Auto">
 								<CheckBox VerticalAlignment="Center" Content="{l:Translate chkCustomFormat}" IsChecked="{Binding Options.UseCustomFormat}" />
-								<TextBox Grid.Column="1" Text="{Binding Format}" IsReadOnly="True" IsVisible="{Binding !Options.UseCustomFormat}" Classes="readonlyFormat" />
-								<TextBox Grid.Column="1" Text="{Binding Options.Format}" IsVisible="{Binding Options.UseCustomFormat}" MaxLength="1000" />
+								<TextBox
+									Grid.Column="1"
+									Text="{Binding Format, Converter={StaticResource NullTextConverter}}"
+									IsReadOnly="True"
+									IsVisible="{Binding !Options.UseCustomFormat}"
+									Classes="readonlyFormat"
+								/>
+								<TextBox
+									Grid.Column="1"
+									Text="{Binding Options.Format, Converter={StaticResource NullTextConverter}}"
+									IsVisible="{Binding Options.UseCustomFormat}"
+									MaxLength="1000"
+								/>
 								<Image Grid.Row="0" Grid.Column="2" Source="/Assets/Help.png" ToolTip.Tip="{Binding FormatTooltip}" ToolTip.Placement="Right" ToolTip.ShowDelay="0" />
 								
 								<TextBlock VerticalAlignment="Center" Grid.Row="1" Text="{l:Translate lblCondition}" />
@@ -137,7 +148,10 @@
 										ToolTip.Placement="Right"
 										ToolTip.ShowDelay="0"
 									/>
-									<TextBox Text="{Binding Options.Condition}" MaxLength="1000" />
+									<TextBox
+										Text="{Binding Options.Condition, Converter={StaticResource NullTextConverter}}"
+										MaxLength="1000"
+									/>
 								</DockPanel>
 							</Grid>
 						</StackPanel>
diff --git a/UI/Styles/DebugStatusStyles.xaml b/UI/Styles/DebugStatusStyles.xaml
index 31c79f6a..b04e47f3 100644
--- a/UI/Styles/DebugStatusStyles.xaml
+++ b/UI/Styles/DebugStatusStyles.xaml
@@ -42,5 +42,7 @@
 
 		<Setter Property="Height" Value="16" />
 		<Setter Property="MinHeight" Value="16" />
+
+		<Setter Property="IsUndoEnabled" Value="False" />
 	</Style>
 </Styles>
diff --git a/UI/Utilities/NullTextConverter.cs b/UI/Utilities/NullTextConverter.cs
new file mode 100644
index 00000000..dc711333
--- /dev/null
+++ b/UI/Utilities/NullTextConverter.cs
@@ -0,0 +1,30 @@
+using Avalonia.Controls;
+using Avalonia.Data.Converters;
+using System;
+
+namespace Mesen.Utilities;
+
+/// <summary>
+/// Used to fix an issue with undo in Avalonia's TextBox.
+/// Typing a string, then undoing multiple times will eventually set
+/// the string to null instead of an empty string, causing crashes
+/// in code that does not expect the string to ever be null.
+/// </summary>
+public class NullTextConverter : IValueConverter
+{
+	public object Convert(object? value, Type targetType, object? parameter, System.Globalization.CultureInfo culture)
+	{
+		if(value is string val) {
+			return val ?? "";
+		}
+		return "";
+	}
+
+	public object ConvertBack(object? value, Type targetType, object? parameter, System.Globalization.CultureInfo culture)
+	{
+		if(value is string s) {
+			return s;
+		}
+		return "";
+	}
+}
diff --git a/UI/Windows/CheatDatabaseWindow.axaml b/UI/Windows/CheatDatabaseWindow.axaml
index 1a348466..507aac12 100644
--- a/UI/Windows/CheatDatabaseWindow.axaml
+++ b/UI/Windows/CheatDatabaseWindow.axaml
@@ -24,7 +24,7 @@
 	<DockPanel>
 		<Grid ColumnDefinitions="Auto,*" RowDefinitions="Auto" DockPanel.Dock="Top">
 			<TextBlock Text="{l:Translate lblSearch}" />
-			<TextBox Grid.Column="1" Text="{Binding SearchString}" Name="Search" />
+			<TextBox Grid.Column="1" Text="{Binding SearchString, Converter={StaticResource NullTextConverter}}" Name="Search" />
 		</Grid>
 		
 		<StackPanel HorizontalAlignment="Right" Orientation="Horizontal" DockPanel.Dock="Bottom" Margin="0 0 1 1">
diff --git a/UI/Windows/CheatEditWindow.axaml b/UI/Windows/CheatEditWindow.axaml
index a28979c7..6cc46420 100644
--- a/UI/Windows/CheatEditWindow.axaml
+++ b/UI/Windows/CheatEditWindow.axaml
@@ -20,7 +20,7 @@
 
 	<Grid ColumnDefinitions="Auto,*" RowDefinitions="Auto,Auto,Auto,*,Auto">
 		<TextBlock Text="{l:Translate lblDescription}" VerticalAlignment="Center" />
-		<TextBox Grid.Column="1" Text="{Binding Cheat.Description}" />
+		<TextBox Grid.Column="1" Text="{Binding Cheat.Description, Converter={StaticResource NullTextConverter}}" />
 	
 		<CheckBox
 			Grid.Row="1"
@@ -47,7 +47,7 @@
 					AcceptsReturn="True"
 					ScrollViewer.HorizontalScrollBarVisibility="Auto"
 					Height="NaN"
-					Text="{Binding Cheat.Codes}"
+					Text="{Binding Cheat.Codes, Converter={StaticResource NullTextConverter}}"
 				/>
 
 				<TextBox
diff --git a/UI/Windows/InputBarcodeWindow.axaml b/UI/Windows/InputBarcodeWindow.axaml
index 13485698..9e37a4e4 100644
--- a/UI/Windows/InputBarcodeWindow.axaml
+++ b/UI/Windows/InputBarcodeWindow.axaml
@@ -25,7 +25,7 @@
 			<TextBox
 				Name="txtBarcode"
 				HorizontalAlignment="Stretch"
-				Text="{Binding Barcode, ElementName=root}"
+				Text="{Binding Barcode, ElementName=root, Converter={StaticResource NullTextConverter}}"
 				MaxLength="13"
 			/>
 		</DockPanel>
diff --git a/UI/Windows/MovieRecordWindow.axaml b/UI/Windows/MovieRecordWindow.axaml
index 44fafe42..5cdfe272 100644
--- a/UI/Windows/MovieRecordWindow.axaml
+++ b/UI/Windows/MovieRecordWindow.axaml
@@ -41,7 +41,7 @@
 				Margin="0 14 0 3"
 			/>
 			<TextBlock Grid.Row="3" Text="{l:Translate lblAuthor}" />
-			<TextBox Grid.Row="3" Grid.Column="1" Grid.ColumnSpan="2" Text="{Binding Config.Author}" />
+			<TextBox Grid.Row="3" Grid.Column="1" Grid.ColumnSpan="2" Text="{Binding Config.Author, Converter={StaticResource NullTextConverter}}" />
 
 			<TextBlock Grid.Row="4" Text="{l:Translate lblDescription}" />
 			<TextBox
@@ -53,7 +53,7 @@
 				VerticalContentAlignment="Top"
 				ScrollViewer.HorizontalScrollBarVisibility="Auto"
 				ScrollViewer.VerticalScrollBarVisibility="Auto"
-				Text="{Binding Config.Description}"
+				Text="{Binding Config.Description, Converter={StaticResource NullTextConverter}}"
 			/>
 		</Grid>
 	</DockPanel>
diff --git a/UI/Windows/NetplayConnectWindow.axaml b/UI/Windows/NetplayConnectWindow.axaml
index ee40ffbb..f9807d54 100644
--- a/UI/Windows/NetplayConnectWindow.axaml
+++ b/UI/Windows/NetplayConnectWindow.axaml
@@ -23,13 +23,13 @@
 
 		<Grid ColumnDefinitions="Auto,1*" RowDefinitions="Auto,Auto,Auto">
 			<TextBlock Text="{l:Translate lblHost}" />
-			<TextBox Grid.Column="1" Text="{Binding Host}" />
+			<TextBox Grid.Column="1" Text="{Binding Host, Converter={StaticResource NullTextConverter}}" />
 
 			<TextBlock Grid.Row="1" Text="{l:Translate lblPort}" />
-			<TextBox Grid.Row="1" Grid.Column="1" Text="{Binding Port}" />
+			<TextBox Grid.Row="1" Grid.Column="1" Text="{Binding Port, Converter={StaticResource NullTextConverter}}" />
 
 			<TextBlock Grid.Row="2" Text="{l:Translate lblPassword}" />
-			<TextBox Grid.Row="2" Grid.Column="1" Text="{Binding Password}" />
+			<TextBox Grid.Row="2" Grid.Column="1" Text="{Binding Password, Converter={StaticResource NullTextConverter}}" />
 		</Grid>
 	</DockPanel>
 </Window>
diff --git a/UI/Windows/NetplayStartServerWindow.axaml b/UI/Windows/NetplayStartServerWindow.axaml
index acf9b2d8..2cbeec47 100644
--- a/UI/Windows/NetplayStartServerWindow.axaml
+++ b/UI/Windows/NetplayStartServerWindow.axaml
@@ -23,10 +23,10 @@
 
 		<Grid ColumnDefinitions="Auto,1*,Auto" RowDefinitions="Auto,Auto,Auto,Auto,Auto">
 			<TextBlock Text="{l:Translate lblPort}" />
-			<TextBox Grid.Column="1" Text="{Binding ServerPort}" />
+			<TextBox Grid.Column="1" Text="{Binding ServerPort, Converter={StaticResource NullTextConverter}}" />
 
 			<TextBlock Grid.Row="1" Text="{l:Translate lblPassword}" />
-			<TextBox Grid.Row="1" Grid.Column="1" Text="{Binding ServerPassword}" />
+			<TextBox Grid.Row="1" Grid.Column="1" Text="{Binding ServerPassword, Converter={StaticResource NullTextConverter}}" />
 		</Grid>
 	</DockPanel>
 </Window>
diff --git a/UI/Windows/SelectRomWindow.axaml b/UI/Windows/SelectRomWindow.axaml
index cb379444..8b1e0279 100644
--- a/UI/Windows/SelectRomWindow.axaml
+++ b/UI/Windows/SelectRomWindow.axaml
@@ -15,7 +15,7 @@
 	<DockPanel HorizontalAlignment="Stretch">
 		<Grid ColumnDefinitions="Auto,*" RowDefinitions="Auto" DockPanel.Dock="Top">
 			<TextBlock Text="{l:Translate lblSearch}" />
-			<TextBox Grid.Column="1" Text="{Binding SearchString}" Name="Search" />
+			<TextBox Grid.Column="1" Text="{Binding SearchString, Converter={StaticResource NullTextConverter}}" Name="Search" />
 		</Grid>
 
 		<StackPanel VerticalAlignment="Center" HorizontalAlignment="Right" Orientation="Horizontal" DockPanel.Dock="Bottom">