org.checkerframework.dataflow.cfg.node.LocalVariableNode Maven / Gradle / Ivy

Go to download
package org.checkerframework.dataflow.cfg.node;

import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;

import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.dataflow.qual.SideEffectFree;
import org.checkerframework.javacutil.TreeUtils;

import java.util.Collection;
import java.util.Collections;
import java.util.Objects;

import javax.lang.model.element.VariableElement;

/**
 * A node for a local variable or a parameter:
 *
 *  *   identifier
 * 
 *
 * We allow local variable uses introduced by the {@link
 * org.checkerframework.dataflow.cfg.builder.CFGBuilder} without corresponding AST {@link Tree}s.
 */
// TODO: don't use for parameters, as they don't have a tree
public class LocalVariableNode extends Node {

    /** The tree for the local variable. */
    protected final Tree tree;

    /** The receiver node for the local variable, {@code null} otherwise. */
    protected final @Nullable Node receiver;

    /**
     * Create a new local variable node for the given tree.
     *
     * @param tree the tree for the local variable: a VariableTree or an IdentifierTree
     */
    public LocalVariableNode(Tree tree) {
        this(tree, null);
    }

    /**
     * Create a new local variable node for the given tree and receiver.
     *
     * @param tree the tree for the local variable: a VariableTree or an IdentifierTree
     * @param receiver the receiver for the local variable, or null if none
     */
    public LocalVariableNode(Tree tree, @Nullable Node receiver) {
        super(TreeUtils.typeOf(tree));
        // IdentifierTree for normal uses of the local variable or parameter,
        // and VariableTree for declarations or the translation of an initializer block
        assert tree != null;
        assert tree instanceof IdentifierTree || tree instanceof VariableTree;
        this.tree = tree;
        this.receiver = receiver;
    }

    /**
     * Returns the element associated with this local variable.
     *
     * @return the element associated with this local variable
     */
    public VariableElement getElement() {
        VariableElement el;
        if (tree instanceof IdentifierTree) {
            IdentifierTree itree = (IdentifierTree) tree;
            assert TreeUtils.isUseOfElement(itree) : "@AssumeAssertion(nullness): tree kind";
            el = TreeUtils.variableElementFromUse(itree);
        } else {
            assert tree instanceof VariableTree;
            el = TreeUtils.elementFromDeclaration((VariableTree) tree);
        }
        return el;
    }

    /** The receiver node for the local variable, {@code null} otherwise. */
    public @Nullable Node getReceiver() {
        return receiver;
    }

    public String getName() {
        if (tree instanceof IdentifierTree) {
            return ((IdentifierTree) tree).getName().toString();
        }
        return ((VariableTree) tree).getName().toString();
    }

    @Override
    public Tree getTree() {
        return tree;
    }

    @Override
    public  R accept(NodeVisitor visitor, P p) {
        return visitor.visitLocalVariable(this, p);
    }

    @Override
    public String toString() {
        return getName().toString();
    }

    @Override
    public boolean equals(@Nullable Object obj) {
        if (!(obj instanceof LocalVariableNode)) {
            return false;
        }
        LocalVariableNode other = (LocalVariableNode) obj;
        return getName().equals(other.getName());
    }

    @Override
    public int hashCode() {
        return Objects.hash(getName());
    }

    @Override
    @SideEffectFree
    public Collection getOperands() {
        return Collections.emptyList();
    }
}