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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Dynamic.Utils;
namespace System.Linq.Expressions
{
/// <summary>
/// Emits or clears a sequence point for debug information.
///
/// This allows the debugger to highlight the correct source code when
/// debugging.
/// </summary>
[DebuggerTypeProxy(typeof(DebugInfoExpressionProxy))]
public class DebugInfoExpression : Expression
{
internal DebugInfoExpression(SymbolDocumentInfo document)
{
Document = document;
}
/// <summary>
/// Gets the static type of the expression that this <see cref="Expression"/> represents. (Inherited from <see cref="Expression"/>.)
/// </summary>
/// <returns>The <see cref="System.Type"/> that represents the static type of the expression.</returns>
public sealed override Type Type => typeof(void);
/// <summary>
/// Returns the node type of this <see cref="Expression"/>. (Inherited from <see cref="Expression"/>.)
/// </summary>
/// <returns>The <see cref="ExpressionType"/> that represents this expression.</returns>
public sealed override ExpressionType NodeType => ExpressionType.DebugInfo;
/// <summary>
/// Gets the start line of this <see cref="DebugInfoExpression"/>.
/// </summary>
[ExcludeFromCodeCoverage(Justification = "Unreachable")]
public virtual int StartLine
{
get { throw ContractUtils.Unreachable; }
}
/// <summary>
/// Gets the start column of this <see cref="DebugInfoExpression"/>.
/// </summary>
[ExcludeFromCodeCoverage(Justification = "Unreachable")]
public virtual int StartColumn
{
get { throw ContractUtils.Unreachable; }
}
/// <summary>
/// Gets the end line of this <see cref="DebugInfoExpression"/>.
/// </summary>
[ExcludeFromCodeCoverage(Justification = "Unreachable")]
public virtual int EndLine
{
get { throw ContractUtils.Unreachable; }
}
/// <summary>
/// Gets the end column of this <see cref="DebugInfoExpression"/>.
/// </summary>
[ExcludeFromCodeCoverage(Justification = "Unreachable")]
public virtual int EndColumn
{
get { throw ContractUtils.Unreachable; }
}
/// <summary>
/// Gets the <see cref="SymbolDocumentInfo"/> that represents the source file.
/// </summary>
public SymbolDocumentInfo Document { get; }
/// <summary>
/// Gets the value to indicate if the <see cref="DebugInfoExpression"/> is for clearing a sequence point.
/// </summary>
[ExcludeFromCodeCoverage(Justification = "Unreachable")]
public virtual bool IsClear
{
get { throw ContractUtils.Unreachable; }
}
/// <summary>
/// Dispatches to the specific visit method for this node type.
/// </summary>
protected internal override Expression Accept(ExpressionVisitor visitor)
{
return visitor.VisitDebugInfo(this);
}
}
#region Specialized subclasses
internal sealed class SpanDebugInfoExpression : DebugInfoExpression
{
private readonly int _startLine, _startColumn, _endLine, _endColumn;
internal SpanDebugInfoExpression(SymbolDocumentInfo document, int startLine, int startColumn, int endLine, int endColumn)
: base(document)
{
_startLine = startLine;
_startColumn = startColumn;
_endLine = endLine;
_endColumn = endColumn;
}
public override int StartLine => _startLine;
public override int StartColumn => _startColumn;
public override int EndLine => _endLine;
public override int EndColumn => _endColumn;
public override bool IsClear => false;
protected internal override Expression Accept(ExpressionVisitor visitor)
{
return visitor.VisitDebugInfo(this);
}
}
internal sealed class ClearDebugInfoExpression : DebugInfoExpression
{
internal ClearDebugInfoExpression(SymbolDocumentInfo document)
: base(document)
{
}
public override bool IsClear => true;
public override int StartLine => 0xfeefee;
public override int StartColumn => 0;
public override int EndLine => 0xfeefee;
public override int EndColumn => 0;
}
#endregion
public partial class Expression
{
/// <summary>
/// Creates a <see cref="DebugInfoExpression"/> with the specified span.
/// </summary>
/// <param name="document">The <see cref="SymbolDocumentInfo"/> that represents the source file.</param>
/// <param name="startLine">The start line of this <see cref="DebugInfoExpression"/>. Must be greater than 0.</param>
/// <param name="startColumn">The start column of this <see cref="DebugInfoExpression"/>. Must be greater than 0.</param>
/// <param name="endLine">The end line of this <see cref="DebugInfoExpression"/>. Must be greater or equal than the start line.</param>
/// <param name="endColumn">The end column of this <see cref="DebugInfoExpression"/>. If the end line is the same as the start line, it must be greater or equal than the start column. In any case, must be greater than 0.</param>
/// <returns>An instance of <see cref="DebugInfoExpression"/>.</returns>
public static DebugInfoExpression DebugInfo(SymbolDocumentInfo document, int startLine, int startColumn, int endLine, int endColumn)
{
ArgumentNullException.ThrowIfNull(document);
if (startLine == 0xfeefee && startColumn == 0 && endLine == 0xfeefee && endColumn == 0)
{
return new ClearDebugInfoExpression(document);
}
ValidateSpan(startLine, startColumn, endLine, endColumn);
return new SpanDebugInfoExpression(document, startLine, startColumn, endLine, endColumn);
}
/// <summary>
/// Creates a <see cref="DebugInfoExpression"/> for clearing a sequence point.
/// </summary>
/// <param name="document">The <see cref="SymbolDocumentInfo"/> that represents the source file.</param>
/// <returns>An instance of <see cref="DebugInfoExpression"/> for clearing a sequence point.</returns>
public static DebugInfoExpression ClearDebugInfo(SymbolDocumentInfo document)
{
ArgumentNullException.ThrowIfNull(document);
return new ClearDebugInfoExpression(document);
}
private static void ValidateSpan(int startLine, int startColumn, int endLine, int endColumn)
{
ArgumentOutOfRangeException.ThrowIfNegativeOrZero(startLine);
ArgumentOutOfRangeException.ThrowIfNegativeOrZero(startColumn);
ArgumentOutOfRangeException.ThrowIfNegativeOrZero(endLine);
ArgumentOutOfRangeException.ThrowIfNegativeOrZero(endColumn);
if (startLine > endLine)
{
throw Error.StartEndMustBeOrdered();
}
if (startLine == endLine && startColumn > endColumn)
{
throw Error.StartEndMustBeOrdered();
}
}
}
}
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