org.checkerframework.checker.nullness.KeyForTransfer Maven / Gradle / Ivy

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The Checker Framework enhances Java's type system to make it more powerful and useful. This lets software developers detect and prevent errors in their Java programs. The Checker Framework includes compiler plug-ins ("checkers") that find bugs or verify their absence. It also permits you to write your own compiler plug-ins.

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package org.checkerframework.checker.nullness;

import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;
import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.ExecutableElement;
import org.checkerframework.checker.nullness.qual.KeyFor;
import org.checkerframework.dataflow.analysis.TransferInput;
import org.checkerframework.dataflow.analysis.TransferResult;
import org.checkerframework.dataflow.cfg.node.MethodInvocationNode;
import org.checkerframework.dataflow.cfg.node.Node;
import org.checkerframework.dataflow.expression.JavaExpression;
import org.checkerframework.framework.flow.CFAbstractTransfer;
import org.checkerframework.javacutil.AnnotationUtils;
import org.checkerframework.javacutil.TreeUtils;

/**
 * KeyForTransfer ensures that java.util.Map.put and containsKey cause the appropriate @KeyFor
 * annotation to be added to the key.
 */
public class KeyForTransfer extends CFAbstractTransfer {

  /** The KeyFor.value element/field. */
  ExecutableElement keyForValueElement;

  /**
   * Creates a new KeyForTransfer.
   *
   * @param analysis the analysis
   */
  public KeyForTransfer(KeyForAnalysis analysis) {
    super(analysis);

    ProcessingEnvironment processingEnv =
        ((KeyForAnnotatedTypeFactory) analysis.getTypeFactory()).getProcessingEnv();
    keyForValueElement = TreeUtils.getMethod(KeyFor.class, "value", 0, processingEnv);
  }

  /*
   * Provided that m is of a type that implements interface java.util.Map:
   * 
   * Given a call m.containsKey(k), ensures that k is @KeyFor("m") in the thenStore of the transfer result.
   * 
Given a call m.put(k, ...), ensures that k is @KeyFor("m") in the thenStore and elseStore of the transfer result.
   * 
   */
  @Override
  public TransferResult visitMethodInvocation(
      MethodInvocationNode node, TransferInput in) {

    TransferResult result = super.visitMethodInvocation(node, in);
    KeyForAnnotatedTypeFactory factory = (KeyForAnnotatedTypeFactory) analysis.getTypeFactory();
    if (factory.isMapContainsKey(node) || factory.isMapPut(node)) {

      Node receiver = node.getTarget().getReceiver();
      JavaExpression receiverJe = JavaExpression.fromNode(receiver);
      String mapName = receiverJe.toString();
      JavaExpression keyExpr = JavaExpression.fromNode(node.getArgument(0));

      LinkedHashSet keyForMaps = new LinkedHashSet<>();
      keyForMaps.add(mapName);

      final KeyForValue previousKeyValue = in.getValueOfSubNode(node.getArgument(0));
      if (previousKeyValue != null) {
        for (AnnotationMirror prevAm : previousKeyValue.getAnnotations()) {
          if (prevAm != null && factory.areSameByClass(prevAm, KeyFor.class)) {
            keyForMaps.addAll(getKeys(prevAm));
          }
        }
      }

      AnnotationMirror am = factory.createKeyForAnnotationMirrorWithValue(keyForMaps);

      if (factory.isMapContainsKey(node)) {
        // method is Map.containsKey
        result.getThenStore().insertValue(keyExpr, am);
      } else {
        // method is Map.put
        result.getThenStore().insertValue(keyExpr, am);
        result.getElseStore().insertValue(keyExpr, am);
      }
    }

    return result;
  }

  /**
   * Returns the elements/arguments of a {@code @KeyFor} annotation.
   *
   * @param keyFor a {@code @KeyFor} annotation
   * @return the elements/arguments of a {@code @KeyFor} annotation
   */
  private Set getKeys(final AnnotationMirror keyFor) {
    if (keyFor.getElementValues().isEmpty()) {
      return Collections.emptySet();
    }

    return new LinkedHashSet<>(
        AnnotationUtils.getElementValueArray(keyFor, keyForValueElement, String.class));
  }
}