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//
// RedundantCatchIssue.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.Refactoring;
namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
[IssueDescription("Redundant catch clause",
Description = "Catch clause with a single 'throw' statement is redundant.",
Category = IssueCategories.Redundancies,
Severity = Severity.Hint,
IssueMarker = IssueMarker.GrayOut,
ResharperDisableKeyword = "RedundantCatchClause")]
public class RedundantCatchIssue : ICodeIssueProvider
{
public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
{
return new GatherVisitor(context).GetIssues();
}
class GatherVisitor : GatherVisitorBase<RedundantCatchIssue>
{
public GatherVisitor(BaseRefactoringContext context) : base (context)
{
}
public override void VisitTryCatchStatement(TryCatchStatement tryCatchStatement)
{
var redundantCatchClauses = new List<CatchClause>();
bool hasNonRedundantCatch = false;
foreach (var catchClause in tryCatchStatement.CatchClauses) {
if (IsRedundant(catchClause)) {
redundantCatchClauses.Add(catchClause);
} else {
hasNonRedundantCatch = true;
}
}
if (hasNonRedundantCatch || !tryCatchStatement.FinallyBlock.IsNull) {
AddIssuesForClauses(tryCatchStatement, redundantCatchClauses);
} else {
AddIssueForTryCatchStatement(tryCatchStatement);
}
}
void AddIssuesForClauses(AstNode node, List<CatchClause> redundantCatchClauses)
{
var allCatchClausesMessage = ctx.TranslateString("Remove all '{0}' redundant 'catch' clauses");
var removeAllRedundantClausesAction = new CodeAction(allCatchClausesMessage, script => {
foreach (var redundantCatchClause in redundantCatchClauses) {
script.Remove(redundantCatchClause);
}
}, node);
var singleCatchClauseMessage = ctx.TranslateString("Remove 'catch'");
var redundantCatchClauseMessage = ctx.TranslateString("Catch clause with a single 'throw' statement is redundant.");
foreach (var redundantCatchClause in redundantCatchClauses) {
var closureLocalCatchClause = redundantCatchClause;
var removeRedundantClauseAction = new CodeAction(singleCatchClauseMessage, script => {
script.Remove(closureLocalCatchClause);
}, node);
var actions = new List<CodeAction>();
actions.Add(removeRedundantClauseAction);
if (redundantCatchClauses.Count > 1) {
actions.Add(removeAllRedundantClausesAction);
}
AddIssue(closureLocalCatchClause, redundantCatchClauseMessage, actions);
}
}
void AddIssueForTryCatchStatement(TryCatchStatement tryCatchStatement)
{
var lastCatch = tryCatchStatement.CatchClauses.LastOrNullObject();
if (lastCatch.IsNull)
return;
var removeTryCatchMessage = ctx.TranslateString("Remove 'try' statement");
var removeTryStatementAction = new CodeAction(removeTryCatchMessage, script => {
var statements = tryCatchStatement.TryBlock.Statements;
if (statements.Count == 1 || tryCatchStatement.Parent is BlockStatement) {
foreach (var statement in statements) {
script.InsertAfter(tryCatchStatement.GetPrevSibling (s => !(s is NewLineNode)), statement.Clone());
}
script.Remove(tryCatchStatement);
} else {
var blockStatement = new BlockStatement();
foreach (var statement in statements) {
blockStatement.Statements.Add(statement.Clone());
}
script.Replace(tryCatchStatement, blockStatement);
}
// The replace and insert script functions does not format these things well on their own
script.FormatText(tryCatchStatement.Parent);
}, tryCatchStatement);
var fixes = new [] {
removeTryStatementAction
};
AddIssue(tryCatchStatement.TryBlock.EndLocation, lastCatch.EndLocation, removeTryCatchMessage, fixes);
}
static bool IsThrowsClause (CatchClause catchClause)
{
var firstStatement = catchClause.Body.Statements.FirstOrNullObject();
if (firstStatement.IsNull)
return false;
var throwStatement = firstStatement as ThrowStatement;
if (throwStatement == null)
return false;
return true;
}
bool IsRedundant(CatchClause catchClause)
{
if (!IsThrowsClause (catchClause))
return false;
var type = ctx.Resolve (catchClause.Type).Type;
var n = catchClause.NextSibling;
while (n != null) {
var nextClause = n as CatchClause;
if (nextClause != null) {
if (nextClause.Type.IsNull && !IsThrowsClause(nextClause))
return false;
if (!IsThrowsClause(nextClause) && type.GetDefinition ().IsDerivedFrom (ctx.Resolve (nextClause.Type).Type.GetDefinition ()))
return false;
}
n = n.NextSibling;
}
return true;
}
}
}
}
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