plugins/groovy/src/org/jetbrains/plugins/groovy/codeInspection/noReturnMethod/MissingReturnInspection.java

   1 /*
   2  * Copyright 2000-2009 JetBrains s.r.o.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package org.jetbrains.plugins.groovy.codeInspection.noReturnMethod;
  17
  18 import com.intellij.codeInspection.ProblemsHolder;
  19 import com.intellij.openapi.util.Ref;
  20 import com.intellij.openapi.util.TextRange;
  21 import com.intellij.psi.PsiElement;
  22 import com.intellij.psi.PsiElementVisitor;
  23 import com.intellij.psi.PsiType;
  24 import org.jetbrains.annotations.Nls;
  25 import org.jetbrains.annotations.NonNls;
  26 import org.jetbrains.annotations.NotNull;
  27 import org.jetbrains.plugins.groovy.codeInspection.GroovyInspectionBundle;
  28 import org.jetbrains.plugins.groovy.codeInspection.GroovySuppressableInspectionTool;
  29 import org.jetbrains.plugins.groovy.codeInspection.utils.ControlFlowUtils;
  30 import org.jetbrains.plugins.groovy.lang.psi.GroovyElementVisitor;
  31 import org.jetbrains.plugins.groovy.lang.psi.GroovyPsiElement;
  32 import org.jetbrains.plugins.groovy.lang.psi.GroovyPsiElementVisitor;
  33 import org.jetbrains.plugins.groovy.lang.psi.GroovyRecursiveElementVisitor;
  34 import org.jetbrains.plugins.groovy.lang.psi.api.statements.blocks.GrClosableBlock;
  35 import org.jetbrains.plugins.groovy.lang.psi.api.statements.blocks.GrCodeBlock;
  36 import org.jetbrains.plugins.groovy.lang.psi.api.statements.blocks.GrOpenBlock;
  37 import org.jetbrains.plugins.groovy.lang.psi.api.statements.branch.GrAssertStatement;
  38 import org.jetbrains.plugins.groovy.lang.psi.api.statements.branch.GrReturnStatement;
  39 import org.jetbrains.plugins.groovy.lang.psi.api.statements.branch.GrThrowStatement;
  40 import org.jetbrains.plugins.groovy.lang.psi.api.statements.typedef.members.GrMethod;
  41 import org.jetbrains.plugins.groovy.lang.psi.controlFlow.Instruction;
  42 import org.jetbrains.plugins.groovy.lang.psi.controlFlow.impl.MaybeReturnInstruction;
  43
  44 /**
  45  * @author ven
  46  */
  47 public class MissingReturnInspection extends GroovySuppressableInspectionTool {
  48   @Nls
  49   @NotNull
  50   public String getGroupDisplayName() {
  51     return GroovyInspectionBundle.message("groovy.dfa.issues");
  52   }
  53
  54   @NotNull
  55   @Override
  56   public String[] getGroupPath() {
  57     return new String[]{"Groovy", getGroupDisplayName()};
  58   }
  59
  60   @Nls
  61   @NotNull
  62   public String getDisplayName() {
  63     return GroovyInspectionBundle.message("no.return.display.name");
  64   }
  65
  66   @NotNull
  67   public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder problemsHolder, boolean onTheFly) {
  68     return new GroovyPsiElementVisitor(new GroovyElementVisitor() {
  69       public void visitClosure(GrClosableBlock closure) {
  70         check(closure, problemsHolder, false);
  71         super.visitClosure(closure);
  72       }
  73
  74       public void visitMethod(GrMethod method) {
  75         final GrOpenBlock block = method.getBlock();
  76         if (block != null) {
  77           final boolean mustReturnValue = method.getReturnTypeElementGroovy() != null && method.getReturnType() != PsiType.VOID;
  78           check(block, problemsHolder, mustReturnValue);
  79         }
  80         super.visitMethod(method);
  81       }
  82     });
  83
  84   }
  85
  86   private static void check(GrCodeBlock block, ProblemsHolder holder, boolean mustReturnValue) {
  87     final Ref<Boolean> always = new Ref<Boolean>(true);
  88     final Ref<Boolean> sometimes = new Ref<Boolean>(false);
  89     ControlFlowUtils.visitAllExitPoints(block, new ControlFlowUtils.ExitPointVisitor() {
  90       public boolean visit(Instruction instruction) {
  91         if (instruction instanceof MaybeReturnInstruction) {
  92           if (((MaybeReturnInstruction)instruction).mayReturnValue()) {
  93             sometimes.set(true);
  94           }
  95           else {
  96             always.set(false);
  97           }
  98           return true;
  99         }
 100         final PsiElement element = instruction.getElement();
 101         if (element instanceof GrReturnStatement || element instanceof GrThrowStatement || element instanceof GrAssertStatement) {
 102           sometimes.set(true);
 103         }
 104         else {
 105           always.set(false);
 106         }
 107         return true;
 108       }
 109     });
 110     if ((mustReturnValue && !sometimes.get()) || (sometimes.get() && !always.get())) {
 111       addNoReturnMessage(block, holder);
 112     }
 113   }
 114
 115   private static void addNoReturnMessage(GrCodeBlock block, ProblemsHolder holder) {
 116     final PsiElement lastChild = block.getLastChild();
 117     if (lastChild == null) return;
 118     TextRange range = lastChild.getTextRange();
 119     if (!lastChild.isValid() || !lastChild.isPhysical() || range.getStartOffset() >= range.getEndOffset()) {
 120       return;
 121     }
 122     holder.registerProblem(lastChild, GroovyInspectionBundle.message("no.return.message"));
 123   }
 124
 125   @NonNls
 126   @NotNull
 127   public String getShortName() {
 128     return "GroovyMissingReturnStatement";
 129   }
 130
 131   public boolean isEnabledByDefault() {
 132     return true;
 133   }
 134 }