package org.checkerframework.dataflow.cfg.node;
/*>>>
import org.checkerframework.checker.nullness.qual.Nullable;
*/
import com.sun.source.tree.Tree;
import java.util.Collection;
import java.util.LinkedList;
import javax.lang.model.type.TypeMirror;
import org.checkerframework.dataflow.cfg.CFGBuilder;
import org.checkerframework.dataflow.cfg.block.Block;
/**
* A node in the abstract representation used for Java code inside a basic block.
*
* <p>The following invariants hold:
*
* <pre>
* block == null || block instanceof RegularBlock || block instanceof ExceptionBlock
* block instanceof RegularBlock ⇒ block.getContents().contains(this)
* block instanceof ExceptionBlock ⇒ block.getNode() == this
* block == null ⇔ "This object represents a parameter of the method."
* </pre>
*
* <pre>
* type != null
* tree != null ⇒ node.getType() == InternalUtils.typeOf(node.getTree())
* </pre>
*
* @author Stefan Heule
*/
public abstract class Node {
/** The basic block this node belongs to (see invariant about this field above). */
protected /*@Nullable*/ Block block;
/** Is this node an l-value? */
protected boolean lvalue = false;
/** The assignment context of this node. See {@link AssignmentContext}. */
protected /*@Nullable*/ AssignmentContext assignmentContext;
/**
* Does this node represent a tree that appears in the source code (true) or one that the CFG
* builder added while desugaring (false).
*/
protected boolean inSource = true;
/**
* The type of this node. For {@link Node}s with {@link Tree}s, this type is the type of the
* {@link Tree}. Otherwise, it is the type is set by the {@link CFGBuilder}.
*/
protected final TypeMirror type;
public Node(TypeMirror type) {
assert type != null;
this.type = type;
}
/**
* @return the basic block this node belongs to (or {@code null} if it represents the parameter
* of a method).
*/
public /*@Nullable*/ Block getBlock() {
return block;
}
/** Set the basic block this node belongs to. */
public void setBlock(Block b) {
block = b;
}
/**
* Returns the {@link Tree} in the abstract syntax tree, or {@code null} if no corresponding
* tree exists. For instance, this is the case for an {@link ImplicitThisLiteralNode}.
*
* @return the corresponding {@link Tree} or {@code null}.
*/
public abstract /*@Nullable*/ Tree getTree();
/**
* Returns a {@link TypeMirror} representing the type of a {@link Node} A {@link Node} will
* always have a type even when it has no {@link Tree}.
*
* @return a {@link TypeMirror} representing the type of this {@link Node}
*/
public TypeMirror getType() {
return type;
}
/**
* Accept method of the visitor pattern
*
* @param <R> result type of the operation
* @param <P> parameter type
* @param visitor the visitor to be applied to this node
* @param p the parameter for this operation
*/
public abstract <R, P> R accept(NodeVisitor<R, P> visitor, P p);
public boolean isLValue() {
return lvalue;
}
/** Make this node an l-value. */
public void setLValue() {
lvalue = true;
}
public boolean getInSource() {
return inSource;
}
public void setInSource(boolean inSrc) {
inSource = inSrc;
}
public AssignmentContext getAssignmentContext() {
return assignmentContext;
}
public void setAssignmentContext(AssignmentContext assignmentContext) {
this.assignmentContext = assignmentContext;
}
/** @return a collection containing all of the operand {@link Node}s of this {@link Node}. */
public abstract Collection<Node> getOperands();
/**
* @return a collection containing all of the operand {@link Node}s of this {@link Node}, as
* well as (transitively) the operands of its operands
*/
public Collection<Node> getTransitiveOperands() {
LinkedList<Node> operands = new LinkedList<>(getOperands());
LinkedList<Node> transitiveOperands = new LinkedList<>();
while (!operands.isEmpty()) {
Node next = operands.removeFirst();
operands.addAll(next.getOperands());
transitiveOperands.add(next);
}
return transitiveOperands;
}
}