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//
// RedundantToStringIssue.cs
//
// Author:
// Simon Lindgren <simon.n.lindgren@gmail.com>
//
// Copyright (c) 2012 Simon Lindgren
//
// 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 ICSharpCode.NRefactory.TypeSystem;
using ICSharpCode.NRefactory.CSharp.Resolver;
using ICSharpCode.NRefactory.Semantics;
using System.Linq;
using ICSharpCode.NRefactory.TypeSystem.Implementation;
namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
[IssueDescription("Redundant call to ToString()",
Description = "Finds calls to ToString() which would occur anyway.",
Category = IssueCategories.Redundancies,
Severity = Severity.Suggestion,
IssueMarker = IssueMarker.GrayOut)]
public class RedundantToStringIssue : ICodeIssueProvider
{
public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
{
return new GatherVisitor(context).GetIssues();
}
class GatherVisitor : GatherVisitorBase
{
static Tuple<int, int> onlyFirst = Tuple.Create (0, 0);
static IDictionary<Tuple<string, int>, Tuple<int, int>> membersCallingToString = new Dictionary<Tuple<string, int>, Tuple<int, int>> {
{ Tuple.Create("System.IO.TextWriter.Write", 1), onlyFirst },
{ Tuple.Create("System.IO.TextWriter.WriteLine", 1), onlyFirst },
{ Tuple.Create("System.Console.Write", 1), onlyFirst },
{ Tuple.Create("System.Console.WriteLine", 1), onlyFirst }
};
public GatherVisitor (BaseRefactoringContext context) : base (context)
{
}
HashSet<AstNode> processedNodes = new HashSet<AstNode>();
void CheckExpressionInAutoCallContext(Expression expression)
{
if (expression is InvocationExpression) {
CheckInvocationInAutoCallContext((InvocationExpression)expression);
}
}
void CheckInvocationInAutoCallContext(InvocationExpression invocationExpression)
{
var memberExpression = invocationExpression.Target as MemberReferenceExpression;
if (memberExpression == null) {
return;
}
var resolveResult = ctx.Resolve(invocationExpression) as CSharpInvocationResolveResult;
if (resolveResult == null) {
return;
}
if (resolveResult.Member.Name != "ToString") {
return;
}
AddRedundantToStringIssue(memberExpression, invocationExpression);
}
void AddRedundantToStringIssue(MemberReferenceExpression memberExpression, InvocationExpression invocationExpression)
{
if (processedNodes.Contains(invocationExpression)) {
return;
}
processedNodes.Add(invocationExpression);
AddIssue(memberExpression.DotToken.StartLocation, invocationExpression.RParToken.EndLocation,
ctx.TranslateString("Remove redundant call to ToString()"), script => {
script.Replace(invocationExpression, memberExpression.Target.Clone());
});
}
#region Binary operator
public override void VisitBinaryOperatorExpression(BinaryOperatorExpression binaryOperatorExpression)
{
base.VisitBinaryOperatorExpression(binaryOperatorExpression);
if (binaryOperatorExpression.Operator != BinaryOperatorType.Add)
return;
var expressions = FlattenBinaryOperator(binaryOperatorExpression);
int stringExpressionCount = 0;
foreach (var expression in expressions) {
var resolveResult = ctx.Resolve(expression);
if (resolveResult.Type.IsKnownType(KnownTypeCode.String)) {
stringExpressionCount++;
}
if (stringExpressionCount > 1) {
break;
}
}
if (stringExpressionCount <= 1) {
return;
}
foreach (var expression in expressions) {
CheckExpressionInAutoCallContext(expression);
}
}
IList<Expression> FlattenBinaryOperator(BinaryOperatorExpression binaryOperatorExpression)
{
var expressions = new List<Expression>();
FlattenBinaryOperator(binaryOperatorExpression, expressions);
return expressions;
}
void FlattenBinaryOperator(BinaryOperatorExpression binaryOperatorExpression, IList<Expression> expressions)
{
FlattenExpression(binaryOperatorExpression.Left, expressions);
FlattenExpression(binaryOperatorExpression.Right, expressions);
}
void FlattenExpression(Expression expression, IList<Expression> expressions)
{
if (expression is BinaryOperatorExpression) {
FlattenBinaryOperator((BinaryOperatorExpression)expression, expressions);
}
else {
expressions.Add(expression);
}
}
#endregion
#region Invocation expression
public override void VisitInvocationExpression(InvocationExpression invocationExpression)
{
base.VisitInvocationExpression(invocationExpression);
var invocationResolveResult = ctx.Resolve(invocationExpression) as CSharpInvocationResolveResult;
if (invocationResolveResult == null) {
return;
}
IMember member = invocationResolveResult.Member;
// "".ToString()
CheckTargetedObject(invocationExpression, invocationResolveResult.TargetResult.Type, member);
// Check list of members that call ToString() automatically
CheckAutomaticToStringCallers(invocationExpression, member);
// Check formatting calls
CheckFormattingCall(invocationExpression, invocationResolveResult);
}
void CheckTargetedObject(InvocationExpression invocationExpression, IType type, IMember member)
{
var memberExpression = invocationExpression.Target as MemberReferenceExpression;
if (memberExpression != null) {
if (type.IsKnownType(KnownTypeCode.String) && member.Name == "ToString") {
AddRedundantToStringIssue(memberExpression, invocationExpression);
}
}
}
void CheckAutomaticToStringCallers(InvocationExpression invocationExpression, IMember member)
{
if (member.IsOverride) {
member = InheritanceHelper.GetBaseMember(member);
if (member == null) {
return;
}
}
var key = new Tuple<string, int>(member.ReflectionName, invocationExpression.Arguments.Count);
Tuple<int, int> checkInfo;
if (membersCallingToString.TryGetValue(key, out checkInfo)) {
var arguments = invocationExpression.Arguments.ToList();
for (int i = checkInfo.Item1; i < Math.Min(invocationExpression.Arguments.Count, checkInfo.Item2 + 1); ++i) {
CheckExpressionInAutoCallContext(arguments[i]);
}
}
}
void CheckFormattingCall(InvocationExpression invocationExpression, CSharpInvocationResolveResult invocationResolveResult)
{
Expression formatArgument;
IList<Expression> formatArguments;
TextLocation formatStart;
// Only check parameters that are of type object: String means it is neccessary, others
// means that there is another problem (ie no matching overload of the method).
Func<IParameter, Expression, bool> predicate = (parameter, argument) => {
var type = parameter.Type;
if (type is TypeWithElementType && parameter.IsParams) {
type = ((TypeWithElementType)type).ElementType;
}
var typeDefinition = type.GetDefinition();
if (typeDefinition == null)
return false;
return typeDefinition.IsKnownType(KnownTypeCode.Object);
};
if (FormatStringHelper.TryGetFormattingParameters(invocationResolveResult, invocationExpression,
out formatArgument, out formatStart, out formatArguments, predicate)) {
foreach (var argument in formatArguments) {
CheckExpressionInAutoCallContext(argument);
}
}
}
#endregion
}
}
}