1 files changed, 132 insertions, 0 deletions

diff --git a/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/initialization/NonThreadSafeLazyInitializationInspectionBase.java b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/initialization/NonThreadSafeLazyInitializationInspectionBase.java
new file mode 100644
index 000000000000..f29c461bcf64
--- /dev/null
+++ b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/initialization/NonThreadSafeLazyInitializationInspectionBase.java
@@ -0,0 +1,132 @@
+/*
+ * Copyright 2003-2014 Dave Griffith, Bas Leijdekkers
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.siyeh.ig.initialization;
+
+import com.intellij.psi.*;
+import com.intellij.psi.tree.IElementType;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.siyeh.InspectionGadgetsBundle;
+import com.siyeh.ig.BaseInspection;
+import com.siyeh.ig.BaseInspectionVisitor;
+import com.siyeh.ig.psiutils.ExpressionUtils;
+import com.siyeh.ig.psiutils.VariableAccessUtils;
+import org.jetbrains.annotations.NotNull;
+
+public class NonThreadSafeLazyInitializationInspectionBase extends BaseInspection {
+
+  @Override
+  @NotNull
+  public String getDisplayName() {
+    return InspectionGadgetsBundle.message(
+      "non.thread.safe.lazy.initialization.display.name");
+  }
+
+  @Override
+  @NotNull
+  public String buildErrorString(Object... infos) {
+    return InspectionGadgetsBundle.message(
+      "non.thread.safe.lazy.initialization.problem.descriptor");
+  }
+
+  @Override
+  public BaseInspectionVisitor buildVisitor() {
+    return new UnsafeSafeLazyInitializationVisitor();
+  }
+
+  private static class UnsafeSafeLazyInitializationVisitor
+    extends BaseInspectionVisitor {
+
+    @Override
+    public void visitAssignmentExpression(
+      @NotNull PsiAssignmentExpression expression) {
+      super.visitAssignmentExpression(expression);
+      final PsiExpression lhs = expression.getLExpression();
+      if (!(lhs instanceof PsiReferenceExpression)) {
+        return;
+      }
+      final PsiReferenceExpression reference = (PsiReferenceExpression)lhs;
+      final PsiElement referent = reference.resolve();
+      if (!(referent instanceof PsiField)) {
+        return;
+      }
+      final PsiField field = (PsiField)referent;
+      if (!field.hasModifierProperty(PsiModifier.STATIC)) {
+        return;
+      }
+      if (isInStaticInitializer(expression)) {
+        return;
+      }
+      if (isInSynchronizedContext(expression)) {
+        return;
+      }
+      final PsiStatement statement = PsiTreeUtil.getParentOfType(expression, PsiStatement.class);
+      final PsiElement parent =
+        PsiTreeUtil.skipParentsOfType(statement, PsiCodeBlock.class, PsiBlockStatement.class);
+      if (!(parent instanceof PsiIfStatement)) {
+        return;
+      }
+      final PsiIfStatement ifStatement = (PsiIfStatement)parent;
+      final PsiExpression condition = ifStatement.getCondition();
+      if (condition == null|| !isNullComparison(condition, field)) {
+        return;
+      }
+      registerError(lhs, ifStatement, field);
+    }
+
+    private static boolean isNullComparison(PsiExpression condition, PsiVariable variable) {
+      if (!(condition instanceof PsiBinaryExpression)) {
+        return false;
+      }
+      final PsiBinaryExpression comparison = (PsiBinaryExpression)condition;
+      final IElementType tokenType = comparison.getOperationTokenType();
+      if (!tokenType.equals(JavaTokenType.EQEQ)) {
+        return false;
+      }
+      final PsiExpression lhs = comparison.getLOperand();
+      final PsiExpression rhs = comparison.getROperand();
+      if (ExpressionUtils.isNullLiteral(rhs)) {
+        return VariableAccessUtils.evaluatesToVariable(lhs, variable);
+      }
+      else if (ExpressionUtils.isNullLiteral(lhs)) {
+        return VariableAccessUtils.evaluatesToVariable(rhs, variable);
+      }
+      return false;
+    }
+
+    private static boolean isInSynchronizedContext(PsiElement element) {
+      final PsiSynchronizedStatement syncBlock =
+        PsiTreeUtil.getParentOfType(element,
+                                    PsiSynchronizedStatement.class);
+      if (syncBlock != null) {
+        return true;
+      }
+      final PsiMethod method =
+        PsiTreeUtil.getParentOfType(element,
+                                    PsiMethod.class);
+      return method != null &&
+             method.hasModifierProperty(PsiModifier.SYNCHRONIZED)
+             && method.hasModifierProperty(PsiModifier.STATIC);
+    }
+
+    private static boolean isInStaticInitializer(PsiElement element) {
+      final PsiClassInitializer initializer =
+        PsiTreeUtil.getParentOfType(element,
+                                    PsiClassInitializer.class);
+      return initializer != null &&
+             initializer.hasModifierProperty(PsiModifier.STATIC);
+    }
+  }
+}
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