Fix TableControl OOM in ScrollablePanel and add ClearContents

Cap unbounded width in TableControl.GetLogicalContentSize to prevent
OutOfMemoryException when hosted in ScrollablePanelControl. Add safety
cap in AnsiConsoleHelper.AnsiEmptySpace as defense in depth. Add
ClearContents method to ScrollablePanelControl. Add Table builder.

Author: nickprotop

SharpConsoleUI/Builders/Controls.cs

@@ -246,6 +246,12 @@ public static FigleControlBuilder Figlet(string? text = null)
 	/// <returns>A new progress bar builder</returns>
 	public static ProgressBarBuilder ProgressBar() => new ProgressBarBuilder();
 
+	/// <summary>
+	/// Creates a new table control builder
+	/// </summary>
+	/// <returns>A new table control builder</returns>
+	public static TableControlBuilder Table() => new TableControlBuilder();
+
 	/// <summary>
 	/// Creates a new panel builder for bordered content panels
 	/// </summary>

SharpConsoleUI/Configuration/LayoutDefaults.cs

@@ -0,0 +1,28 @@
+// -----------------------------------------------------------------------
+// ConsoleEx - A simple console window system for .NET Core
+//
+// Author: Nikolaos Protopapas
+// Email: nikolaos.protopapas@gmail.com
+// License: MIT
+// -----------------------------------------------------------------------
+
+namespace SharpConsoleUI.Configuration
+{
+	/// <summary>
+	/// Centralized default values for layout measurement and rendering width limits.
+	/// </summary>
+	public static class LayoutDefaults
+	{
+		/// <summary>
+		/// Width used by GetLogicalContentSize when no explicit width is set.
+		/// Prevents unbounded allocation when measuring Spectre renderables.
+		/// </summary>
+		public const int DefaultUnboundedMeasureWidth = 1000;
+
+		/// <summary>
+		/// Hard safety cap for AnsiEmptySpace to prevent OOM from any caller
+		/// passing an excessively large width.
+		/// </summary>
+		public const int MaxSafeRenderWidth = 10000;
+	}
+}

SharpConsoleUI/Controls/ScrollablePanelControl.cs

@@ -996,6 +996,29 @@ public void RemoveControl(IWindowControl control)
 			}
 		}
 
+		/// <summary>
+		/// Removes all child controls from the panel.
+		/// </summary>
+		public void ClearContents()
+		{
+			if (_focusedChild is IFocusableControl fc)
+				fc.SetFocus(false, FocusReason.Programmatic);
+			_focusedChild = null;
+			_lastInternalFocusedChild = null;
+
+			foreach (var child in _children)
+			{
+				child.Container = null;
+				child.Dispose();
+			}
+			_children.Clear();
+
+			if (_hasFocus && !CanReceiveFocus)
+				SetFocus(false, FocusReason.Programmatic);
+
+			Invalidate(true);
+		}
+
 		/// <summary>
 		/// Gets the collection of child controls.
 		/// </summary>

SharpConsoleUI/Controls/TableControl.cs

@@ -743,7 +743,8 @@ public bool ProcessMouseEvent(MouseEventArgs args)
 	/// <inheritdoc/>
 	public System.Drawing.Size GetLogicalContentSize()
 	{
-		var constraints = new LayoutConstraints(0, int.MaxValue, 0, int.MaxValue);
+		int maxWidth = _width ?? LayoutDefaults.DefaultUnboundedMeasureWidth;
+		var constraints = new LayoutConstraints(0, maxWidth, 0, int.MaxValue);
 		var size = MeasureDOM(constraints);
 		return new System.Drawing.Size(size.Width, size.Height);
 	}

SharpConsoleUI/Helpers/AnsiConsoleHelper.cs

@@ -6,6 +6,7 @@
 // License: MIT
 // -----------------------------------------------------------------------
 
+using SharpConsoleUI.Configuration;
 using Spectre.Console;
 using Spectre.Console.Rendering;
 using System;
@@ -66,6 +67,7 @@ public static string AnsiEmptySpace(int width, Color backgroundColor)
 		{
 			if (width <= 0)
 				return string.Empty;
+			width = Math.Min(width, LayoutDefaults.MaxSafeRenderWidth);
 			return ConvertSpectreMarkupToAnsi($"{new string(' ', width)}", width, 1, false, backgroundColor, null)[0];
 		}