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* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package jdk.nashorn.internal.ir;
import jdk.nashorn.internal.ir.annotations.Immutable;
import jdk.nashorn.internal.ir.visitor.NodeVisitor;
/**
* Node represents a var/let declaration.
*/
@Immutable
public final class VarNode extends Statement implements Assignment<IdentNode> {
private static final long serialVersionUID = 1L;
/** Var name. */
private final IdentNode name;
/** Initialization expression. */
private final Expression init;
/** Is this a var statement (as opposed to a "var" in a for loop statement) */
private final int flags;
/**
* source order id to be used for this node. If this is -1, then we
* the default which is start position of this node. See also the
* method Node::getSourceOrder.
*/
private final int sourceOrder;
/** Flag for ES6 LET declaration */
public static final int IS_LET = 1 << 0;
/** Flag for ES6 CONST declaration */
public static final int IS_CONST = 1 << 1;
/** Flag that determines if this is the last function declaration in a function
* This is used to micro optimize the placement of return value assignments for
* a program node */
public static final int IS_LAST_FUNCTION_DECLARATION = 1 << 2;
/**
* Constructor
*
* @param lineNumber line number
* @param token token
* @param finish finish
* @param name name of variable
* @param init init node or null if just a declaration
*/
public VarNode(final int lineNumber, final long token, final int finish, final IdentNode name, final Expression init) {
this(lineNumber, token, finish, name, init, 0);
}
private VarNode(final VarNode varNode, final IdentNode name, final Expression init, final int flags) {
super(varNode);
this.sourceOrder = -1;
this.name = init == null ? name : name.setIsInitializedHere();
this.init = init;
this.flags = flags;
}
/**
* Constructor
*
* @param lineNumber line number
* @param token token
* @param finish finish
* @param name name of variable
* @param init init node or null if just a declaration
* @param flags flags
*/
public VarNode(final int lineNumber, final long token, final int finish, final IdentNode name, final Expression init, final int flags) {
this(lineNumber, token, -1, finish, name, init, flags);
}
/**
* Constructor
*
* @param lineNumber line number
* @param token token
* @param sourceOrder source order
* @param finish finish
* @param name name of variable
* @param init init node or null if just a declaration
* @param flags flags
*/
public VarNode(final int lineNumber, final long token, final int sourceOrder, final int finish, final IdentNode name, final Expression init, final int flags) {
super(lineNumber, token, finish);
this.sourceOrder = sourceOrder;
this.name = init == null ? name : name.setIsInitializedHere();
this.init = init;
this.flags = flags;
}
@Override
public int getSourceOrder() {
return sourceOrder == -1? super.getSourceOrder() : sourceOrder;
}
@Override
public boolean isAssignment() {
return hasInit();
}
@Override
public IdentNode getAssignmentDest() {
return isAssignment() ? name : null;
}
@Override
public VarNode setAssignmentDest(final IdentNode n) {
return setName(n);
}
@Override
public Expression getAssignmentSource() {
return isAssignment() ? getInit() : null;
}
/**
* Is this a VAR node block scoped? This returns true for ECMAScript 6 LET and CONST nodes.
* @return true if an ES6 LET or CONST node
*/
public boolean isBlockScoped() {
return getFlag(IS_LET) || getFlag(IS_CONST);
}
/**
* Is this an ECMAScript 6 LET node?
* @return true if LET node
*/
public boolean isLet() {
return getFlag(IS_LET);
}
/**
* Is this an ECMAScript 6 CONST node?
* @return true if CONST node
*/
public boolean isConst() {
return getFlag(IS_CONST);
}
/**
* Return the flags to use for symbols for this declaration.
* @return the symbol flags
*/
public int getSymbolFlags() {
if (isLet()) {
return Symbol.IS_VAR | Symbol.IS_LET;
} else if (isConst()) {
return Symbol.IS_VAR | Symbol.IS_CONST;
}
return Symbol.IS_VAR;
}
/**
* Does this variable declaration have an init value
* @return true if an init exists, false otherwise
*/
public boolean hasInit() {
return init != null;
}
/**
* Assist in IR navigation.
* @param visitor IR navigating visitor.
*/
@Override
public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
if (visitor.enterVarNode(this)) {
// var is right associative, so visit init before name
final Expression newInit = init == null ? null : (Expression)init.accept(visitor);
final IdentNode newName = (IdentNode)name.accept(visitor);
final VarNode newThis;
if (name != newName || init != newInit) {
newThis = new VarNode(this, newName, newInit, flags);
} else {
newThis = this;
}
return visitor.leaveVarNode(newThis);
}
return this;
}
@Override
public void toString(final StringBuilder sb, final boolean printType) {
sb.append(tokenType().getName()).append(' ');
name.toString(sb, printType);
if (init != null) {
sb.append(" = ");
init.toString(sb, printType);
}
}
/**
* If this is an assignment of the form {@code var x = init;}, get the init part.
* @return the expression to initialize the variable to, null if just a declaration
*/
public Expression getInit() {
return init;
}
/**
* Reset the initialization expression
* @param init new initialization expression
* @return a node equivalent to this one except for the requested change.
*/
public VarNode setInit(final Expression init) {
if (this.init == init) {
return this;
}
return new VarNode(this, name, init, flags);
}
/**
* Get the identifier for the variable
* @return IdentNode representing the variable being set or declared
*/
public IdentNode getName() {
return name;
}
/**
* Reset the identifier for this VarNode
* @param name new IdentNode representing the variable being set or declared
* @return a node equivalent to this one except for the requested change.
*/
public VarNode setName(final IdentNode name) {
if (this.name == name) {
return this;
}
return new VarNode(this, name, init, flags);
}
private VarNode setFlags(final int flags) {
if (this.flags == flags) {
return this;
}
return new VarNode(this, name, init, flags);
}
/**
* Check if a flag is set for this var node
* @param flag flag
* @return true if flag is set
*/
public boolean getFlag(final int flag) {
return (flags & flag) == flag;
}
/**
* Set a flag for this var node
* @param flag flag
* @return new node if flags changed, same otherwise
*/
public VarNode setFlag(final int flag) {
return setFlags(flags | flag);
}
/**
* Returns true if this is a function declaration.
* @return true if this is a function declaration.
*/
public boolean isFunctionDeclaration() {
return init instanceof FunctionNode && ((FunctionNode)init).isDeclared();
}
}