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package org.checkerframework.dataflow.cfg.node;
import com.sun.source.tree.Tree;
import org.checkerframework.checker.initialization.qual.UnknownInitialization;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.dataflow.cfg.block.Block;
import org.checkerframework.dataflow.cfg.builder.CFGBuilder;
import org.checkerframework.dataflow.qual.Pure;
import org.checkerframework.dataflow.qual.SideEffectFree;
import org.plumelib.util.UniqueId;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.StringJoiner;
import java.util.concurrent.atomic.AtomicLong;
import javax.lang.model.type.TypeMirror;
/**
* A node in the abstract representation used for Java code inside a basic block.
*
* The following invariants hold:
*
*
* block == null || block instanceof RegularBlock || block instanceof ExceptionBlock
* block != null ⇔ block.getNodes().contains(this)
*
*
*
* type != null
* tree != null ⇒ node.getType() == InternalUtils.typeOf(node.getTree())
*
*
* Note that two {@code Node}s can be {@code .equals} but represent different CFG nodes. Take care
* to use reference equality, maps that handle identity {@code IdentityHashMap}, and sets like
* {@code IdentityArraySet}.
*/
public abstract class Node implements UniqueId {
/**
* The basic block this node belongs to. If null, this object represents a method formal
* parameter.
*
* Is set by {@link #setBlock}.
*/
protected @Nullable Block block;
/**
* Is this node an l-value?
*
*
Is set by {@link #setLValue}.
*/
protected boolean lvalue = false;
/**
* Does this node represent a tree that appears in the source code (true) or one that the CFG
* builder added while desugaring (false).
*
*
Is set by {@link #setInSource}.
*/
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;
/** The unique ID for the next-created object. */
private static final AtomicLong nextUid = new AtomicLong(0);
/** The unique ID of this object. */
private final transient long uid = nextUid.getAndIncrement();
@Override
@Pure
public long getUid(@UnknownInitialization Node this) {
return uid;
}
/**
* Creates a new Node.
*
* @param type the type of the node
*/
protected Node(TypeMirror type) {
assert type != null;
this.type = type;
}
/**
* Returns the basic block this node belongs to (or {@code null} if it represents the parameter
* of a method).
*
* @return the basic block this node belongs to (or {@code null} if it represents the parameter
* of a method)
*/
@Pure
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 ImplicitThisNode}.
*
* @return the corresponding {@link Tree} or {@code null}
*/
@Pure
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}
*/
@Pure
public TypeMirror getType() {
return type;
}
/**
* Accept method of the visitor pattern.
*
* @param result type of the operation
* @param parameter type
* @param visitor the visitor to be applied to this node
* @param p the parameter for this operation
*/
public abstract R accept(NodeVisitor visitor, P p);
/** Is the node an lvalue or not? */
@Pure
public boolean isLValue() {
return lvalue;
}
/** Make this node an l-value. */
public void setLValue() {
lvalue = true;
}
/**
* Return whether this node represents a tree that appears in the source code (true) or one that
* the CFG or builder added while desugaring (false).
*
* @return whether this node represents a tree that appears in the source code
*/
@Pure
public boolean getInSource() {
return inSource;
}
public void setInSource(boolean inSrc) {
inSource = inSrc;
}
/**
* Returns a collection containing all of the operand {@link Node}s of this {@link Node}.
*
* @return a collection containing all of the operand {@link Node}s of this {@link Node}
*/
@SideEffectFree
public abstract Collection getOperands();
/**
* Returns a collection containing all of the operand {@link Node}s of this {@link Node}, as
* well as (transitively) the operands of its operands.
*
* @return a collection containing all of the operand {@link Node}s of this {@link Node}, as
* well as (transitively) the operands of its operands
*/
@Pure
public Collection getTransitiveOperands() {
ArrayDeque operands = new ArrayDeque<>(getOperands());
ArrayDeque transitiveOperands = new ArrayDeque<>(operands.size());
while (!operands.isEmpty()) {
Node next = operands.removeFirst();
operands.addAll(next.getOperands());
transitiveOperands.add(next);
}
return transitiveOperands;
}
/**
* Returns a verbose string representation of this, useful for debugging.
*
* @return a printed representation of this
*/
@Pure
public String toStringDebug() {
return String.format("%s [%s]", this, this.getClassAndUid());
}
/**
* Returns a verbose string representation of a collection of nodes, useful for debugging..
*
* @param nodes a collection of nodes to format
* @return a printed representation of the given collection
*/
@Pure
public static String nodeCollectionToString(Collection nodes) {
StringJoiner result = new StringJoiner(", ", "[", "]");
for (Node n : nodes) {
result.add(n.toStringDebug());
}
return result.toString();
}
}