SharpDevelop/ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/ConvertToStaticMethodIssue.cs

//
// ConvertToStaticMethodIssue.cs
//
// Author:
//       Ciprian Khlud <ciprian.mustiata@yahoo.com>
//
// Copyright (c) 2013 Ciprian Khlud
//
// 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.Collections.Generic;
using ICSharpCode.NRefactory.Semantics;
using System.Linq;
using ICSharpCode.NRefactory.TypeSystem;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
//	[IssueDescription("Make this method static",
//                      Description = "This method doesn't use any non static members so it can be made static",
//                      Severity = Severity.Hint,
//                      IssueMarker = IssueMarker.Underline)]
    public class ConvertToStaticMethodIssue : ICodeIssueProvider
	{
		public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
		{
			return new GatherVisitor(context).GetIssues();
		}

		private class GatherVisitor : GatherVisitorBase<ConvertToStaticMethodIssue>
		{
			public GatherVisitor(BaseRefactoringContext context)
                : base(context)
			{
			}

			public override void VisitMethodDeclaration(MethodDeclaration methodDeclaration)
			{
				// TODO: Invert if without else
				// ex. if (cond) DoSomething () == if (!cond) return; DoSomething ()
				// beware of loop contexts return should be continue then.
				var context = ctx;
				if (methodDeclaration.HasModifier(Modifiers.Static) || 
				    methodDeclaration.HasModifier(Modifiers.Virtual) || 
				    methodDeclaration.HasModifier(Modifiers.Override) || 
				    methodDeclaration.HasModifier(Modifiers.New) || 
				    methodDeclaration.Attributes.Any())
					return;

				// skip empty methods
				if (!methodDeclaration.Body.Statements.Any())
					return;

				if (methodDeclaration.Body.Statements.Count == 1) {
					if (methodDeclaration.Body.Statements.First () is ThrowStatement)
						return;
				}
					
				var resolved = context.Resolve(methodDeclaration) as MemberResolveResult;
				if (resolved == null)
					return;

				var isImplementingInterface = resolved.Member.ImplementedInterfaceMembers.Any();
				if (isImplementingInterface)
					return;

				AddIssue(methodDeclaration.NameToken.StartLocation, methodDeclaration.NameToken.EndLocation,
				                     context.TranslateString(string.Format("Make '{0}' static", methodDeclaration.Name)),
				                     script => ExecuteScriptToFixStaticMethodIssue(script, context, methodDeclaration));
			}

			static void ExecuteScriptToFixStaticMethodIssue(Script script,
			                                                                 BaseRefactoringContext context, 
			                                                                 AstNode methodDeclaration)
			{
				var clonedDeclaration = (MethodDeclaration)methodDeclaration.Clone();
				clonedDeclaration.Modifiers |= Modifiers.Static;
				script.Replace(methodDeclaration, clonedDeclaration);
				var rr = context.Resolve(methodDeclaration) as MemberResolveResult;
				//var method = (IMethod)rr.Member;
				//method.ImplementedInterfaceMembers.Any(m => methodGroupResolveResult.Methods.Contains((IMethod)m));

				script.DoGlobalOperationOn(rr.Member,
				                                       (fctx, fscript, fnode) => {
					DoStaticMethodGlobalOperation(fnode, fctx, rr, fscript); });
			}

			static void DoStaticMethodGlobalOperation(AstNode fnode, RefactoringContext fctx, MemberResolveResult rr,
			                                                           Script fscript)
			{
				if (fnode is MemberReferenceExpression) {
					var memberReference = new MemberReferenceExpression(
						new TypeReferenceExpression(fctx.CreateShortType(rr.Member.DeclaringType)),
						rr.Member.Name
					);
					fscript.Replace(fnode, memberReference);
				} else {
					var invoke = fnode as InvocationExpression;
					if (invoke == null)
						return;
					if ((invoke.Target is MemberReferenceExpression))
						return;
					var memberReference = new MemberReferenceExpression(
						new TypeReferenceExpression(fctx.CreateShortType(rr.Member.DeclaringType)),
						rr.Member.Name
					);
					fscript.Replace(invoke.Target, memberReference);
				}
			}
		}
	}
}