[CodeAction]Added ConvertSwitchToIfAction

ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj

@@ -242,6 +242,7 @@
     <Compile Include="Parser\mcs\visit.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Refactoring\CodeActions\ConvertIfToSwitchAction.cs" />
+    <Compile Include="Refactoring\CodeActions\ConvertSwitchToIfAction.cs" />
     <Compile Include="Refactoring\CodeIssues\ExplicitConversionInForEachIssue.cs" />
     <Compile Include="Refactoring\DocumentScript.cs" />
     <Compile Include="Refactoring\PatternHelper.cs" />

ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/ConvertSwitchToIfAction.cs

@@ -0,0 +1,147 @@
+// 
+// ConvertSwitchToIfAction.cs
+//  
+// Author:
+//       Mansheng Yang <lightyang0@gmail.com>
+// 
+// Copyright (c) 2012 Mansheng Yang <lightyang0@gmail.com>
+// 
+// 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.Linq;
+
+namespace ICSharpCode.NRefactory.CSharp.Refactoring
+{
+	[ContextAction ("Convert 'switch' to 'if'", Description = "Convert 'switch' statement to 'if' statement")]
+	public class ConvertSwitchToIfAction : SpecializedCodeAction<SwitchStatement>
+	{
+		static readonly InsertParenthesesVisitor insertParenthesesVisitor = new InsertParenthesesVisitor ();
+
+		protected override CodeAction GetAction (RefactoringContext context, SwitchStatement node)
+		{
+			if (!node.Contains (context.Location))
+				return null;
+
+			// empty switch
+			if (node.SwitchSections.Count == 0)
+				return null;
+
+			// switch with default only
+			if (node.SwitchSections.First ().CaseLabels.Any (label => label.Expression.IsNull))
+				return null;
+
+			// check non-trailing breaks
+			foreach (var switchSection in node.SwitchSections) {
+				var lastStatement = switchSection.Statements.LastOrDefault ();
+				var finder = new NonTrailingBreakFinder (lastStatement as BreakStatement);
+				if (switchSection.AcceptVisitor (finder))
+					return null;
+			}
+			
+			return new CodeAction (context.TranslateString ("Convert 'switch' to 'if'"),
+				script =>
+				{
+					IfElseStatement ifStatement = null;
+					IfElseStatement currentStatement = null;
+					foreach (var switchSection in node.SwitchSections) {
+						var condition = CollectCondition (node.Expression, switchSection.CaseLabels);
+						var bodyStatement = new BlockStatement ();
+						var lastStatement = switchSection.Statements.LastOrDefault ();
+						foreach (var statement in switchSection.Statements) {
+							// skip trailing break
+							if (statement == lastStatement && statement is BreakStatement)
+								continue;
+							bodyStatement.Add (statement.Clone ());
+						}
+
+						// default -> else
+						if (condition == null) {
+							currentStatement.FalseStatement = bodyStatement;
+							break;
+						}
+						var elseIfStatement = new IfElseStatement (condition, bodyStatement);
+						if (ifStatement == null)
+							ifStatement = elseIfStatement;
+						else
+							currentStatement.FalseStatement = elseIfStatement;
+						currentStatement = elseIfStatement;
+					}
+					script.Replace (node, ifStatement);
+					script.FormatText (ifStatement);
+				});
+		}
+
+		static Expression CollectCondition(Expression switchExpr, AstNodeCollection<CaseLabel> caseLabels)
+		{
+			// default
+			if (caseLabels.Count == 0 || caseLabels.Any (label => label.Expression.IsNull))
+				return null;
+
+			var conditionList = caseLabels.Select (
+				label => new BinaryOperatorExpression (switchExpr.Clone (), BinaryOperatorType.Equality, label.Expression.Clone ()))
+				.ToArray ();
+
+			// insert necessary parentheses
+			foreach (var expr in conditionList)
+				expr.AcceptVisitor (insertParenthesesVisitor);
+
+			if (conditionList.Length == 1)
+				return conditionList [0];
+
+			// combine case labels into an conditional or expression
+			BinaryOperatorExpression condition = null;
+			BinaryOperatorExpression currentCondition = null;
+			for (int i = 0; i < conditionList.Length - 1; i++) {
+				var newCondition = new BinaryOperatorExpression
+				{
+					Operator = BinaryOperatorType.ConditionalOr,
+					Left = conditionList[i]
+				};
+				if (currentCondition == null)
+					condition = newCondition;
+				else
+					currentCondition.Right = newCondition;
+				currentCondition = newCondition;
+			}
+			currentCondition.Right = conditionList [conditionList.Length - 1];
+
+			return condition;
+		}
+		
+		class NonTrailingBreakFinder : DepthFirstAstVisitor<bool>
+		{
+			BreakStatement trailingBreakStatement;
+
+			public NonTrailingBreakFinder (BreakStatement trailingBreak)
+			{
+				trailingBreakStatement = trailingBreak;
+			}
+
+			protected override bool VisitChildren (AstNode node)
+			{
+				return node.Children.Any (child => child.AcceptVisitor (this));
+			}
+
+			public override bool VisitBreakStatement (BreakStatement breakStatement)
+			{
+				return breakStatement != trailingBreakStatement;
+			}
+		}
+	}
+}

ICSharpCode.NRefactory.Tests/CSharp/CodeActions/ConvertSwitchToIfTests.cs

@@ -0,0 +1,244 @@
+// 
+// ConvertSwitchToIfTests.cs
+//  
+// Author:
+//       Mansheng Yang <lightyang0@gmail.com>
+// 
+// Copyright (c) 2012 Mansheng Yang <lightyang0@gmail.com>
+// 
+// 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 ICSharpCode.NRefactory.CSharp.Refactoring;
+using NUnit.Framework;
+
+namespace ICSharpCode.NRefactory.CSharp.CodeActions
+{
+	[TestFixture]
+	public class ConvertSwitchToIfTests : ContextActionTestBase
+	{
+		[Test]
+		public void TestReturn ()
+		{
+			Test<ConvertSwitchToIfAction> (@"
+class TestClass
+{
+	int TestMethod (int a)
+	{
+		$switch (a) {
+		case 0:
+			return 0;
+		case 1:
+		case 2:
+			return 1;
+		case 3:
+		case 4:
+		case 5:
+			return 1;
+		default:
+			return 2;
+		}
+	}
+}", @"
+class TestClass
+{
+	int TestMethod (int a)
+	{
+		if (a == 0) {
+			return 0;
+		} else
+			if (a == 1 || a == 2) {
+			return 1;
+		} else
+				if (a == 3 || a == 4 || a == 5) {
+			return 1;
+		} else {
+			return 2;
+		}
+	}
+}");
+		}
+
+		[Test]
+		public void TestWithoutDefault ()
+		{
+			Test<ConvertSwitchToIfAction> (@"
+class TestClass
+{
+	int TestMethod (int a)
+	{
+		$switch (a) {
+		case 0:
+			return 0;
+		case 1:
+		case 2:
+			return 1;
+		case 3:
+		case 4:
+		case 5:
+			return 1;
+		}
+	}
+}", @"
+class TestClass
+{
+	int TestMethod (int a)
+	{
+		if (a == 0) {
+			return 0;
+		} else
+			if (a == 1 || a == 2) {
+			return 1;
+		} else
+				if (a == 3 || a == 4 || a == 5) {
+			return 1;
+		}
+	}
+}");
+		}
+
+		[Test]
+		public void TestBreak ()
+		{
+			Test<ConvertSwitchToIfAction> (@"
+class TestClass
+{
+	void TestMethod (int a)
+	{
+		$switch (a) {
+		case 0:
+			int b = 1;
+			break;
+		case 1:
+		case 2:
+			break;
+		case 3:
+		case 4:
+		case 5:
+			break;
+		default:
+			break;
+		}
+	}
+}", @"
+class TestClass
+{
+	void TestMethod (int a)
+	{
+		if (a == 0) {
+			int b = 1;
+		} else
+			if (a == 1 || a == 2) {
+		} else
+				if (a == 3 || a == 4 || a == 5) {
+		} else {
+		}
+	}
+}");
+		}
+		
+		[Test]
+		public void TestOperatorPriority ()
+		{
+			Test<ConvertSwitchToIfAction> (@"
+class TestClass
+{
+	int TestMethod (int a)
+	{
+		$switch (a) {
+		case 0:
+			return 0;
+		case 1 == 1 ? 1 : 2:
+			return 1;
+		default:
+			return 2;
+		}
+	}
+}", @"
+class TestClass
+{
+	int TestMethod (int a)
+	{
+		if (a == 0) {
+			return 0;
+		} else
+			if (a == (1 == 1 ? 1 : 2)) {
+			return 1;
+		} else {
+			return 2;
+		}
+	}
+}");
+		}
+
+		[Test]
+		public void TestEmptySwitch ()
+		{
+			TestWrongContext<ConvertSwitchToIfAction> (@"
+class TestClass
+{
+	void TestMethod (int a)
+	{
+		$switch (a)
+		{
+		}
+	}
+}");
+		}
+
+		[Test]
+		public void TestSwitchWithDefaultOnly ()
+		{
+			TestWrongContext<ConvertSwitchToIfAction> (@"
+class TestClass
+{
+	void TestMethod (int a)
+	{
+		$switch (a)
+		{
+			case 0:
+			default:
+			break;
+		}
+	}
+}");
+		}
+		
+		[Test]
+		public void TestNonTrailingBreak ()
+		{
+			TestWrongContext<ConvertSwitchToIfAction> (@"
+class TestClass
+{
+	void TestMethod (int a, int b)
+	{
+		$switch (a)
+		{
+			case 0:
+				if (b == 0) break;
+				b = 1;
+				break;
+			default:
+			break;
+		}
+	}
+}");
+		}
+	
+	}
+}

ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj

@@ -82,6 +82,7 @@
     <Compile Include="CSharp\Analysis\DefiniteAssignmentTests.cs" />
     <Compile Include="CSharp\AstStructureTests.cs" />
     <Compile Include="CSharp\CodeActions\ConvertIfToSwtichTests.cs" />
+    <Compile Include="CSharp\CodeActions\ConvertSwitchToIfTests.cs" />
     <Compile Include="CSharp\CodeIssues\ExplicitConversionInForEachIssueTests.cs" />
     <Compile Include="CSharp\CSharpAmbienceTests.cs" />
     <Compile Include="CSharp\CodeDomConvertVisitorTests.cs" />