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// 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.NRefactory.CSharp;
using ICSharpCode.NRefactory.PatternMatching;
using Mono.Cecil;
namespace ICSharpCode.Decompiler.Ast.Transforms
{
/// <summary>
/// If the first element of a constructor is a chained constructor call, convert it into a constructor initializer.
/// </summary>
public class ConvertConstructorCallIntoInitializer : DepthFirstAstVisitor<object, object>, IAstTransform
{
public override object VisitConstructorDeclaration(ConstructorDeclaration constructorDeclaration, object data)
{
ExpressionStatement stmt = constructorDeclaration.Body.Statements.FirstOrDefault() as ExpressionStatement;
if (stmt == null)
return null;
InvocationExpression invocation = stmt.Expression as InvocationExpression;
if (invocation == null)
return null;
MemberReferenceExpression mre = invocation.Target as MemberReferenceExpression;
if (mre != null && mre.MemberName == ".ctor") {
ConstructorInitializer ci = new ConstructorInitializer();
if (mre.Target is ThisReferenceExpression)
ci.ConstructorInitializerType = ConstructorInitializerType.This;
else if (mre.Target is BaseReferenceExpression)
ci.ConstructorInitializerType = ConstructorInitializerType.Base;
else
return null;
// Move arguments from invocation to initializer:
invocation.Arguments.MoveTo(ci.Arguments);
// Add the initializer: (unless it is the default 'base()')
if (!(ci.ConstructorInitializerType == ConstructorInitializerType.Base && ci.Arguments.Count == 0))
constructorDeclaration.Initializer = ci.WithAnnotation(invocation.Annotation<MethodReference>());
// Remove the statement:
stmt.Remove();
}
return null;
}
static readonly ExpressionStatement fieldInitializerPattern = new ExpressionStatement {
Expression = new AssignmentExpression {
Left = new NamedNode("fieldAccess", new MemberReferenceExpression {
Target = new ThisReferenceExpression(),
MemberName = Pattern.AnyString
}),
Operator = AssignmentOperatorType.Assign,
Right = new AnyNode("initializer")
}
};
static readonly AstNode thisCallPattern = new ExpressionStatement(new ThisReferenceExpression().Invoke(".ctor", new Repeat(new AnyNode())));
public override object VisitTypeDeclaration(TypeDeclaration typeDeclaration, object data)
{
// Handle initializers on instance fields
HandleInstanceFieldInitializers(typeDeclaration.Members);
// Now convert base constructor calls to initializers:
base.VisitTypeDeclaration(typeDeclaration, data);
// Remove single empty constructor:
RemoveSingleEmptyConstructor(typeDeclaration);
// Handle initializers on static fields:
HandleStaticFieldInitializers(typeDeclaration.Members);
return null;
}
void HandleInstanceFieldInitializers(IEnumerable<AstNode> members)
{
var instanceCtors = members.OfType<ConstructorDeclaration>().Where(c => (c.Modifiers & Modifiers.Static) == 0).ToArray();
var instanceCtorsNotChainingWithThis = instanceCtors.Where(ctor => !thisCallPattern.IsMatch(ctor.Body.Statements.FirstOrDefault())).ToArray();
if (instanceCtorsNotChainingWithThis.Length > 0) {
MethodDefinition ctorMethodDef = instanceCtorsNotChainingWithThis[0].Annotation<MethodDefinition>();
if (ctorMethodDef != null && ctorMethodDef.DeclaringType.IsValueType)
return;
// Recognize field initializers:
// Convert first statement in all ctors (if all ctors have the same statement) into a field initializer.
bool allSame;
do {
Match m = fieldInitializerPattern.Match(instanceCtorsNotChainingWithThis[0].Body.FirstOrDefault());
if (!m.Success)
break;
FieldDefinition fieldDef = m.Get<AstNode>("fieldAccess").Single().Annotation<FieldReference>().ResolveWithinSameModule();
if (fieldDef == null)
break;
AstNode fieldOrEventDecl = members.FirstOrDefault(f => f.Annotation<FieldDefinition>() == fieldDef);
if (fieldOrEventDecl == null)
break;
Expression initializer = m.Get<Expression>("initializer").Single();
// 'this'/'base' cannot be used in field initializers
if (initializer.DescendantsAndSelf.Any(n => n is ThisReferenceExpression || n is BaseReferenceExpression))
break;
allSame = true;
for (int i = 1; i < instanceCtorsNotChainingWithThis.Length; i++) {
if (!instanceCtors[0].Body.First().IsMatch(instanceCtorsNotChainingWithThis[i].Body.FirstOrDefault()))
allSame = false;
}
if (allSame) {
foreach (var ctor in instanceCtorsNotChainingWithThis)
ctor.Body.First().Remove();
fieldOrEventDecl.GetChildrenByRole(Roles.Variable).Single().Initializer = initializer.Detach();
}
} while (allSame);
}
}
void RemoveSingleEmptyConstructor(TypeDeclaration typeDeclaration)
{
var instanceCtors = typeDeclaration.Members.OfType<ConstructorDeclaration>().Where(c => (c.Modifiers & Modifiers.Static) == 0).ToArray();
if (instanceCtors.Length == 1) {
ConstructorDeclaration emptyCtor = new ConstructorDeclaration();
emptyCtor.Modifiers = ((typeDeclaration.Modifiers & Modifiers.Abstract) == Modifiers.Abstract ? Modifiers.Protected : Modifiers.Public);
emptyCtor.Body = new BlockStatement();
if (emptyCtor.IsMatch(instanceCtors[0]))
instanceCtors[0].Remove();
}
}
void HandleStaticFieldInitializers(IEnumerable<AstNode> members)
{
// Convert static constructor into field initializers if the class is BeforeFieldInit
var staticCtor = members.OfType<ConstructorDeclaration>().FirstOrDefault(c => (c.Modifiers & Modifiers.Static) == Modifiers.Static);
if (staticCtor != null) {
MethodDefinition ctorMethodDef = staticCtor.Annotation<MethodDefinition>();
if (ctorMethodDef != null && ctorMethodDef.DeclaringType.IsBeforeFieldInit) {
while (true) {
ExpressionStatement es = staticCtor.Body.Statements.FirstOrDefault() as ExpressionStatement;
if (es == null)
break;
AssignmentExpression assignment = es.Expression as AssignmentExpression;
if (assignment == null || assignment.Operator != AssignmentOperatorType.Assign)
break;
FieldDefinition fieldDef = assignment.Left.Annotation<FieldReference>().ResolveWithinSameModule();
if (fieldDef == null || !fieldDef.IsStatic)
break;
FieldDeclaration fieldDecl = members.OfType<FieldDeclaration>().FirstOrDefault(f => f.Annotation<FieldDefinition>() == fieldDef);
if (fieldDecl == null)
break;
fieldDecl.Variables.Single().Initializer = assignment.Right.Detach();
es.Remove();
}
if (staticCtor.Body.Statements.Count == 0)
staticCtor.Remove();
}
}
}
void IAstTransform.Run(AstNode node)
{
// If we're viewing some set of members (fields are direct children of CompilationUnit),
// we also need to handle those:
HandleInstanceFieldInitializers(node.Children);
HandleStaticFieldInitializers(node.Children);
node.AcceptVisitor(this, null);
}
}
}
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