ILSpy/ICSharpCode.Decompiler/CecilExtensions.cs

// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Linq;
using ICSharpCode.Decompiler.TypeSystem;
using Mono.Cecil;
using Mono.Cecil.Cil;
using ArrayType = Mono.Cecil.ArrayType;

namespace ICSharpCode.Decompiler
{
	/// <summary>
	/// Cecil helper methods.
	/// </summary>
	public static class CecilExtensions
	{
		/// <summary>
		/// Gets the (exclusive) end offset of this instruction.
		/// </summary>
		public static int GetEndOffset(this Instruction inst)
		{
			if (inst == null)
				throw new ArgumentNullException(nameof(inst));
			return inst.Offset + inst.GetSize();
		}
		
		public static string OffsetToString(int offset)
		{
			return string.Format("IL_{0:x4}", offset);
		}
		
		public static string OffsetToString(long offset)
		{
			return string.Format("IL_{0:x4}", offset);
		}
		
		public static FieldDefinition ResolveWithinSameModule(this FieldReference field)
		{
			if (field != null && field.DeclaringType.GetElementType().Module == field.Module)
				return field.Resolve();
			else
				return null;
		}
		
		public static MethodDefinition ResolveWithinSameModule(this MethodReference method)
		{
			if (method != null && method.DeclaringType.GetElementType().Module == method.Module)
				return method.Resolve();
			else
				return null;
		}

		public static TypeDefinition ResolveOrThrow(this TypeReference typeReference)
		{
			var resolved = typeReference.Resolve();
			if (resolved == null)
				throw new ReferenceResolvingException();
			return resolved;
		}

		public static bool IsCompilerGenerated(this ICustomAttributeProvider provider)
		{
			if (provider != null && provider.HasCustomAttributes) {
				foreach (CustomAttribute a in provider.CustomAttributes) {
					if (a.AttributeType.FullName == "System.Runtime.CompilerServices.CompilerGeneratedAttribute")
						return true;
				}
			}
			return false;
		}
		
		public static bool IsCompilerGeneratedOrIsInCompilerGeneratedClass(this IMemberDefinition member)
		{
			if (member == null)
				return false;
			if (member.IsCompilerGenerated())
				return true;
			return IsCompilerGeneratedOrIsInCompilerGeneratedClass(member.DeclaringType);
		}

		public static TypeReference GetEnumUnderlyingType(this TypeDefinition type)
		{
			if (!type.IsEnum)
				throw new ArgumentException("Type must be an enum", nameof(type));

			var fields = type.Fields;

			for (int i = 0; i < fields.Count; i++)
			{
				var field = fields[i];
				if (!field.IsStatic)
					return field.FieldType;
			}

			throw new NotSupportedException();
		}
		
		public static bool IsAnonymousType(this TypeReference type)
		{
			if (type == null)
				return false;
			if (string.IsNullOrEmpty(type.Namespace) && type.HasGeneratedName() && (type.Name.Contains("AnonType") || type.Name.Contains("AnonymousType"))) {
				TypeDefinition td = type.Resolve();
				return td != null && td.IsCompilerGenerated();
			}
			return false;
		}

		public static bool HasGeneratedName(this MemberReference member)
		{
			return member.Name.StartsWith("<", StringComparison.Ordinal);
		}
		
		public static bool ContainsAnonymousType(this TypeReference type)
		{
			GenericInstanceType git = type as GenericInstanceType;
			if (git != null) {
				if (IsAnonymousType(git))
					return true;
				for (int i = 0; i < git.GenericArguments.Count; i++) {
					if (git.GenericArguments[i].ContainsAnonymousType())
						return true;
				}
				return false;
			}
			TypeSpecification typeSpec = type as TypeSpecification;
			if (typeSpec != null)
				return typeSpec.ElementType.ContainsAnonymousType();
			else
				return false;
		}

		public static string GetDefaultMemberName(this TypeDefinition type)
		{
			CustomAttribute attr;
			return type.GetDefaultMemberName(out attr);
		}

		public static string GetDefaultMemberName(this TypeDefinition type, out CustomAttribute defaultMemberAttribute)
		{
			if (type.HasCustomAttributes)
				foreach (CustomAttribute ca in type.CustomAttributes)
					if (ca.Constructor.DeclaringType.Name == "DefaultMemberAttribute" && ca.Constructor.DeclaringType.Namespace == "System.Reflection"
						&& ca.Constructor.FullName == @"System.Void System.Reflection.DefaultMemberAttribute::.ctor(System.String)") {
						defaultMemberAttribute = ca;
						return ca.ConstructorArguments[0].Value as string;
					}
			defaultMemberAttribute = null;
			return null;
		}

		public static bool IsIndexer(this PropertyDefinition property)
		{
			CustomAttribute attr;
			return property.IsIndexer(out attr);
		}

		public static bool IsIndexer(this PropertyDefinition property, out CustomAttribute defaultMemberAttribute)
		{
			defaultMemberAttribute = null;
			if (property.HasParameters) {
				var accessor = property.GetMethod ?? property.SetMethod;
				PropertyDefinition basePropDef = property;
				if (accessor.HasOverrides) {
					// if the property is explicitly implementing an interface, look up the property in the interface:
					MethodDefinition baseAccessor = accessor.Overrides.First().Resolve();
					if (baseAccessor != null) {
						foreach (PropertyDefinition baseProp in baseAccessor.DeclaringType.Properties) {
							if (baseProp.GetMethod == baseAccessor || baseProp.SetMethod == baseAccessor) {
								basePropDef = baseProp;
								break;
							}
						}
					} else
						return false;
				}
				CustomAttribute attr;
				var defaultMemberName = basePropDef.DeclaringType.GetDefaultMemberName(out attr);
				if (defaultMemberName == basePropDef.Name) {
					defaultMemberAttribute = attr;
					return true;
				}
			}
			return false;
		}

		public static bool IsUnconditionalBranch(this OpCode opcode)
		{
			if (opcode.OpCodeType == OpCodeType.Prefix)
				return false;
			switch (opcode.FlowControl) {
				case FlowControl.Branch:
				case FlowControl.Throw:
				case FlowControl.Return:
					return true;
				case FlowControl.Next:
				case FlowControl.Call:
				case FlowControl.Cond_Branch:
					return false;
				default:
					throw new NotSupportedException(opcode.FlowControl.ToString());
			}
		}

		public static bool IsDelegate(this TypeDefinition type)
		{
			if (type.BaseType != null && type.BaseType.Namespace == "System") {
				if (type.BaseType.Name == "MulticastDelegate")
					return true;
				if (type.BaseType.Name == "Delegate" && type.Name != "MulticastDelegate")
					return true;
			}
			return false;
		}
	}
}