com.google.javascript.jscomp.NodeUtil Maven / Gradle / Ivy
/*
* Copyright 2004 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableSet;
import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.InputId;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.JSDocInfoBuilder;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.StaticSourceFile;
import com.google.javascript.rhino.Token;
import com.google.javascript.rhino.TokenStream;
import com.google.javascript.rhino.TokenUtil;
import com.google.javascript.rhino.dtoa.DToA;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.TernaryValue;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* NodeUtil contains generally useful AST utilities.
*
* @author [email protected] (Nick Santos)
* @author [email protected] (John Lenz)
*/
public final class NodeUtil {
static final long MAX_POSITIVE_INTEGER_NUMBER = 1L << 53;
static final String JSC_PROPERTY_NAME_FN = "JSCompiler_renameProperty";
static final char LARGEST_BASIC_LATIN = 0x7f;
/** the set of builtin constructors that don't have side effects. */
private static final Set CONSTRUCTORS_WITHOUT_SIDE_EFFECTS =
ImmutableSet.of(
"Array",
"Date",
"Error",
"Object",
"RegExp",
"XMLHttpRequest");
// Utility class; do not instantiate.
private NodeUtil() {}
static boolean isImpureTrue(Node n) {
return getImpureBooleanValue(n) == TernaryValue.TRUE;
}
/**
* Gets the boolean value of a node that represents a expression. This method
* effectively emulates the Boolean() JavaScript cast function.
* Note: unlike getPureBooleanValue this function does not return UNKNOWN
* for expressions with side-effects.
*/
static TernaryValue getImpureBooleanValue(Node n) {
switch (n.getType()) {
case Token.ASSIGN:
case Token.COMMA:
// For ASSIGN and COMMA the value is the value of the RHS.
return getImpureBooleanValue(n.getLastChild());
case Token.NOT:
TernaryValue value = getImpureBooleanValue(n.getLastChild());
return value.not();
case Token.AND: {
TernaryValue lhs = getImpureBooleanValue(n.getFirstChild());
TernaryValue rhs = getImpureBooleanValue(n.getLastChild());
return lhs.and(rhs);
}
case Token.OR: {
TernaryValue lhs = getImpureBooleanValue(n.getFirstChild());
TernaryValue rhs = getImpureBooleanValue(n.getLastChild());
return lhs.or(rhs);
}
case Token.HOOK: {
TernaryValue trueValue = getImpureBooleanValue(
n.getSecondChild());
TernaryValue falseValue = getImpureBooleanValue(n.getLastChild());
if (trueValue.equals(falseValue)) {
return trueValue;
} else {
return TernaryValue.UNKNOWN;
}
}
case Token.NEW:
case Token.ARRAYLIT:
case Token.OBJECTLIT:
// ignoring side-effects
return TernaryValue.TRUE;
case Token.VOID:
return TernaryValue.FALSE;
default:
return getPureBooleanValue(n);
}
}
/**
* Gets the boolean value of a node that represents a literal. This method
* effectively emulates the Boolean() JavaScript cast function
* except it return UNKNOWN for known values with side-effects, use
* getImpureBooleanValue if you don't care about side-effects.
*/
static TernaryValue getPureBooleanValue(Node n) {
switch (n.getType()) {
case Token.TEMPLATELIT:
if (n.hasOneChild()) {
return TernaryValue.forBoolean(!n.getFirstChild().getString().isEmpty());
}
break;
case Token.STRING:
return TernaryValue.forBoolean(n.getString().length() > 0);
case Token.NUMBER:
return TernaryValue.forBoolean(n.getDouble() != 0);
case Token.NOT:
return getPureBooleanValue(n.getLastChild()).not();
case Token.NULL:
case Token.FALSE:
return TernaryValue.FALSE;
case Token.VOID:
if (!mayHaveSideEffects(n.getFirstChild())) {
return TernaryValue.FALSE;
}
break;
case Token.NAME:
String name = n.getString();
if ("undefined".equals(name)
|| "NaN".equals(name)) {
// We assume here that programs don't change the value of the keyword
// undefined to something other than the value undefined.
return TernaryValue.FALSE;
} else if ("Infinity".equals(name)) {
return TernaryValue.TRUE;
}
break;
case Token.TRUE:
case Token.REGEXP:
return TernaryValue.TRUE;
case Token.FUNCTION:
case Token.CLASS:
case Token.NEW:
case Token.ARRAYLIT:
case Token.OBJECTLIT:
if (!mayHaveSideEffects(n)) {
return TernaryValue.TRUE;
}
break;
}
return TernaryValue.UNKNOWN;
}
/**
* Gets the value of a node as a String, or null if it cannot be converted.
* When it returns a non-null String, this method effectively emulates the
* String() JavaScript cast function.
*/
public static String getStringValue(Node n) {
// TODO(user): regex literals as well.
switch (n.getType()) {
case Token.STRING:
case Token.STRING_KEY:
return n.getString();
case Token.NAME:
String name = n.getString();
if ("undefined".equals(name)
|| "Infinity".equals(name)
|| "NaN".equals(name)) {
return name;
}
break;
case Token.NUMBER:
return DToA.numberToString(n.getDouble());
case Token.FALSE:
return "false";
case Token.TRUE:
return "true";
case Token.NULL:
return "null";
case Token.VOID:
return "undefined";
case Token.NOT:
TernaryValue child = getPureBooleanValue(n.getFirstChild());
if (child != TernaryValue.UNKNOWN) {
return child.toBoolean(true) ? "false" : "true"; // reversed.
}
break;
case Token.ARRAYLIT:
return arrayToString(n);
case Token.OBJECTLIT:
return "[object Object]";
}
return null;
}
/**
* When converting arrays to string using Array.prototype.toString or
* Array.prototype.join, the rules for conversion to String are different
* than converting each element individually. Specifically, "null" and
* "undefined" are converted to an empty string.
* @param n A node that is a member of an Array.
* @return The string representation.
*/
static String getArrayElementStringValue(Node n) {
return (NodeUtil.isNullOrUndefined(n) || n.isEmpty())
? "" : getStringValue(n);
}
static String arrayToString(Node literal) {
Node first = literal.getFirstChild();
StringBuilder result = new StringBuilder();
for (Node n = first; n != null; n = n.getNext()) {
String childValue = getArrayElementStringValue(n);
if (childValue == null) {
return null;
}
if (n != first) {
result.append(',');
}
result.append(childValue);
}
return result.toString();
}
public static Double getNumberValue(Node n) {
return getNumberValue(n, false);
}
/**
* Gets the value of a node as a Number, or null if it cannot be converted.
* When it returns a non-null Double, this method effectively emulates the
* Number() JavaScript cast function.
*
* @param n The node.
* @param useType If true, return 0.0 if the type is null, and NaN if the type is undefined.
* @return The value of a node as a Number, or null if it cannot be converted.
*/
static Double getNumberValue(Node n, boolean useType) {
switch (n.getType()) {
case Token.TRUE:
return 1.0;
case Token.FALSE:
case Token.NULL:
return 0.0;
case Token.NUMBER:
return n.getDouble();
case Token.VOID:
if (mayHaveSideEffects(n.getFirstChild())) {
return null;
} else {
return Double.NaN;
}
case Token.NAME:
// Check for known constants
String name = n.getString();
if (name.equals("undefined")) {
return Double.NaN;
}
if (name.equals("NaN")) {
return Double.NaN;
}
if (name.equals("Infinity")) {
return Double.POSITIVE_INFINITY;
}
if (useType) {
JSType type = n.getJSType();
if (type != null) {
if (type.isVoidType()) {
return Double.NaN;
} else if (type.isNullType()) {
return 0.0;
}
}
}
return null;
case Token.NEG:
if (n.getChildCount() == 1 && n.getFirstChild().isName()
&& n.getFirstChild().getString().equals("Infinity")) {
return Double.NEGATIVE_INFINITY;
}
return null;
case Token.NOT:
TernaryValue child = getPureBooleanValue(n.getFirstChild());
if (child != TernaryValue.UNKNOWN) {
return child.toBoolean(true) ? 0.0 : 1.0; // reversed.
}
break;
case Token.STRING:
return getStringNumberValue(n.getString());
case Token.ARRAYLIT:
case Token.OBJECTLIT:
String value = getStringValue(n);
return value != null ? getStringNumberValue(value) : null;
}
return null;
}
static Double getStringNumberValue(String rawJsString) {
if (rawJsString.contains("\u000b")) {
// vertical tab is not always whitespace
return null;
}
String s = trimJsWhiteSpace(rawJsString);
// return ScriptRuntime.toNumber(s);
if (s.isEmpty()) {
return 0.0;
}
if (s.length() > 2
&& s.charAt(0) == '0'
&& (s.charAt(1) == 'x' || s.charAt(1) == 'X')) {
// Attempt to convert hex numbers.
try {
return Double.valueOf(Integer.parseInt(s.substring(2), 16));
} catch (NumberFormatException e) {
return Double.NaN;
}
}
if (s.length() > 3
&& (s.charAt(0) == '-' || s.charAt(0) == '+')
&& s.charAt(1) == '0'
&& (s.charAt(2) == 'x' || s.charAt(2) == 'X')) {
// hex numbers with explicit signs vary between browsers.
return null;
}
// Firefox and IE treat the "Infinity" differently. Firefox is case
// insensitive, but IE treats "infinity" as NaN. So leave it alone.
if (s.equals("infinity")
|| s.equals("-infinity")
|| s.equals("+infinity")) {
return null;
}
try {
return Double.parseDouble(s);
} catch (NumberFormatException e) {
return Double.NaN;
}
}
static String trimJsWhiteSpace(String s) {
int start = 0;
int end = s.length();
while (end > 0
&& TokenUtil.isStrWhiteSpaceChar(s.charAt(end - 1)) == TernaryValue.TRUE) {
end--;
}
while (start < end
&& TokenUtil.isStrWhiteSpaceChar(s.charAt(start)) == TernaryValue.TRUE) {
start++;
}
return s.substring(start, end);
}
/**
* @param n A function or class node.
* @return The name of the given function or class, if it has one.
*/
public static String getName(Node n) {
Node nameNode = getNameNode(n);
return nameNode == null ? null : nameNode.getQualifiedName();
}
/**
* Gets the node of a function or class's name. This method recognizes five forms:
*
* - {@code class name {...}}
* - {@code var name = class {...}}
* - {@code qualified.name = class {...}}
* - {@code var name2 = class name1 {...}}
* - {@code qualified.name2 = class name1 {...}}
*
* In two last cases with named function expressions, the second name is
* returned (the variable or qualified name).
*
* @param n A function or class node
* @return the node best representing the class's name
*/
public static Node getNameNode(Node n) {
Preconditions.checkState(n.isFunction() || n.isClass());
Node parent = n.getParent();
switch (parent.getType()) {
case Token.NAME:
// var name = function() ...
// var name2 = function name1() ...
return parent;
case Token.ASSIGN: {
// qualified.name = function() ...
// qualified.name2 = function name1() ...
Node firstChild = parent.getFirstChild();
return firstChild.isQualifiedName() ? firstChild : null;
}
default:
// function name() ...
Node funNameNode = n.getFirstChild();
// Don't return the name node for anonymous functions/classes.
// TODO(tbreisacher): Currently we do two kinds of "empty" checks because
// anonymous classes have an EMPTY name node while anonymous functions
// have a STRING node with an empty string. Consider making these the same.
return (funNameNode.isEmpty() || funNameNode.getString().isEmpty())
? null : funNameNode;
}
}
/**
* Gets the function's name. This method recognizes the forms:
*
* - {@code {'name': function() ...}}
* - {@code {name: function() ...}}
* - {@code function name() ...}
* - {@code var name = function() ...}
* - {@code var obj = {name() {} ...}}
* - {@code qualified.name = function() ...}
* - {@code var name2 = function name1() ...}
* - {@code qualified.name2 = function name1() ...}
*
*
* @param n a node whose type is {@link Token#FUNCTION}
* @return the function's name, or {@code null} if it has no name
*/
public static String getNearestFunctionName(Node n) {
if (!n.isFunction()) {
return null;
}
String name = getName(n);
if (name != null) {
return name;
}
// Check for the form { 'x' : function() { }} and {x() {}}
Node parent = n.getParent();
switch (parent.getType()) {
case Token.MEMBER_FUNCTION_DEF:
case Token.SETTER_DEF:
case Token.GETTER_DEF:
case Token.STRING_KEY:
// Return the name of the literal's key.
return parent.getString();
case Token.NUMBER:
return getStringValue(parent);
}
return null;
}
public static Node getClassMembers(Node n) {
Preconditions.checkArgument(n.isClass());
return n.getLastChild();
}
/**
* Returns true if this is an immutable value.
*/
static boolean isImmutableValue(Node n) {
// TODO(johnlenz): rename this function. It is currently being used
// in two disjoint cases:
// 1) We only care about the result of the expression
// (in which case NOT here should return true)
// 2) We care that expression is a side-effect free and can't
// be side-effected by other expressions.
// This should only be used to say the value is immuable and
// hasSideEffects and canBeSideEffected should be used for the other case.
switch (n.getType()) {
case Token.STRING:
case Token.NUMBER:
case Token.NULL:
case Token.TRUE:
case Token.FALSE:
return true;
case Token.CAST:
case Token.NOT:
case Token.VOID:
case Token.NEG:
return isImmutableValue(n.getFirstChild());
case Token.NAME:
String name = n.getString();
// We assume here that programs don't change the value of the keyword
// undefined to something other than the value undefined.
return "undefined".equals(name) || "Infinity".equals(name) || "NaN".equals(name);
}
return false;
}
/**
* Returns true if the operator on this node is symmetric
*/
static boolean isSymmetricOperation(Node n) {
switch (n.getType()) {
case Token.EQ: // equal
case Token.NE: // not equal
case Token.SHEQ: // exactly equal
case Token.SHNE: // exactly not equal
case Token.MUL: // multiply, unlike add it only works on numbers
// or results NaN if any of the operators is not a number
return true;
}
return false;
}
/**
* Returns true if the operator on this node is relational.
* the returned set does not include the equalities.
*/
static boolean isRelationalOperation(Node n) {
switch (n.getType()) {
case Token.GT: // equal
case Token.GE: // not equal
case Token.LT: // exactly equal
case Token.LE: // exactly not equal
return true;
}
return false;
}
static boolean isAssignmentTarget(Node n) {
Node parent = n.getParent();
if ((isAssignmentOp(parent) && parent.getFirstChild() == n)
|| parent.isInc()
|| parent.isDec()
|| (isForIn(parent) && parent.getFirstChild() == n)) {
// If GETPROP/GETELEM is used as assignment target the object literal is
// acting as a temporary we can't fold it here:
// "{a:x}.a += 1" is not "x += 1"
return true;
}
return false;
}
/**
* Returns the inverse of an operator if it is invertible.
* ex. '>' ==> '<'
*/
static int getInverseOperator(int type) {
switch (type) {
case Token.GT:
return Token.LT;
case Token.LT:
return Token.GT;
case Token.GE:
return Token.LE;
case Token.LE:
return Token.GE;
default:
throw new IllegalArgumentException(
"Unexpected token: " + Token.name(type));
}
}
/**
* Returns true if this is a literal value. We define a literal value
* as any node that evaluates to the same thing regardless of when or
* where it is evaluated. So /xyz/ and [3, 5] are literals, but
* the name a is not.
*
* Function literals do not meet this definition, because they
* lexically capture variables. For example, if you have
*
* function() { return a; }
*
* If it is evaluated in a different scope, then it
* captures a different variable. Even if the function did not read
* any captured variables directly, it would still fail this definition,
* because it affects the lifecycle of variables in the enclosing scope.
*
*
However, a function literal with respect to a particular scope is
* a literal.
*
* @param includeFunctions If true, all function expressions will be
* treated as literals.
*/
public static boolean isLiteralValue(Node n, boolean includeFunctions) {
switch (n.getType()) {
case Token.CAST:
return isLiteralValue(n.getFirstChild(), includeFunctions);
case Token.ARRAYLIT:
for (Node child = n.getFirstChild(); child != null;
child = child.getNext()) {
if ((!child.isEmpty()) && !isLiteralValue(child, includeFunctions)) {
return false;
}
}
return true;
case Token.REGEXP:
// Return true only if all descendants are const.
for (Node child = n.getFirstChild(); child != null;
child = child.getNext()) {
if (!isLiteralValue(child, includeFunctions)) {
return false;
}
}
return true;
case Token.OBJECTLIT:
// Return true only if all values are const.
for (Node child = n.getFirstChild(); child != null;
child = child.getNext()) {
if (!isLiteralValue(child.getFirstChild(), includeFunctions)) {
return false;
}
}
return true;
case Token.FUNCTION:
return includeFunctions && !NodeUtil.isFunctionDeclaration(n);
default:
return isImmutableValue(n);
}
}
/**
* Determines whether the given value may be assigned to a define.
*
* @param val The value being assigned.
* @param defines The list of names of existing defines.
*/
static boolean isValidDefineValue(Node val, Set defines) {
switch (val.getType()) {
case Token.STRING:
case Token.NUMBER:
case Token.TRUE:
case Token.FALSE:
return true;
// Binary operators are only valid if both children are valid.
case Token.AND:
case Token.OR:
case Token.ADD:
case Token.BITAND:
case Token.BITNOT:
case Token.BITOR:
case Token.BITXOR:
case Token.DIV:
case Token.EQ:
case Token.GE:
case Token.GT:
case Token.LE:
case Token.LSH:
case Token.LT:
case Token.MOD:
case Token.MUL:
case Token.NE:
case Token.RSH:
case Token.SHEQ:
case Token.SHNE:
case Token.SUB:
case Token.URSH:
return isValidDefineValue(val.getFirstChild(), defines)
&& isValidDefineValue(val.getLastChild(), defines);
// Unary operators are valid if the child is valid.
case Token.NOT:
case Token.NEG:
case Token.POS:
return isValidDefineValue(val.getFirstChild(), defines);
// Names are valid if and only if they are defines themselves.
case Token.NAME:
case Token.GETPROP:
if (val.isQualifiedName()) {
return defines.contains(val.getQualifiedName());
}
}
return false;
}
/**
* Returns whether this a BLOCK node with no children.
*
* @param block The node.
*/
static boolean isEmptyBlock(Node block) {
if (!block.isBlock()) {
return false;
}
for (Node n = block.getFirstChild(); n != null; n = n.getNext()) {
if (!n.isEmpty()) {
return false;
}
}
return true;
}
static boolean isSimpleOperator(Node n) {
return isSimpleOperatorType(n.getType());
}
/**
* A "simple" operator is one whose children are expressions,
* has no direct side-effects (unlike '+='), and has no
* conditional aspects (unlike '||').
*/
static boolean isSimpleOperatorType(int type) {
switch (type) {
case Token.ADD:
case Token.BITAND:
case Token.BITNOT:
case Token.BITOR:
case Token.BITXOR:
case Token.COMMA:
case Token.DIV:
case Token.EQ:
case Token.GE:
case Token.GETELEM:
case Token.GETPROP:
case Token.GT:
case Token.INSTANCEOF:
case Token.LE:
case Token.LSH:
case Token.LT:
case Token.MOD:
case Token.MUL:
case Token.NE:
case Token.NOT:
case Token.RSH:
case Token.SHEQ:
case Token.SHNE:
case Token.SUB:
case Token.TYPEOF:
case Token.VOID:
case Token.POS:
case Token.NEG:
case Token.URSH:
return true;
default:
return false;
}
}
static boolean isTypedefDecl(Node n) {
if (n.isVar()
|| n.isName() && n.getParent().isVar()
|| n.isGetProp() && n.getParent().isExprResult()) {
JSDocInfo jsdoc = getBestJSDocInfo(n);
return jsdoc != null && jsdoc.hasTypedefType();
}
return false;
}
static boolean isEnumDecl(Node n) {
if (n.isVar()
|| n.isName() && n.getParent().isVar()
|| (n.isGetProp() && n.getParent().isAssign()
&& n.getGrandparent().isExprResult())
|| (n.isAssign() && n.getParent().isExprResult())) {
JSDocInfo jsdoc = getBestJSDocInfo(n);
return jsdoc != null && jsdoc.hasEnumParameterType();
}
return false;
}
/**
* Returns true iff this node defines a namespace, e.g.,
*
* /** @const * / var goog = {};
* /** @const * / var goog = goog || {};
* /** @const * / goog.math = goog.math || {};
*/
static boolean isNamespaceDecl(Node n) {
JSDocInfo jsdoc = getBestJSDocInfo(n);
if (jsdoc != null && !jsdoc.getTypeNodes().isEmpty()) {
return false;
}
// In externs, we allow namespace definitions without @const.
// This is a worse design than always requiring @const, but it helps with
// namespaces that are defined in many places, such as gapi.
// Also, omitting @const in externs is not as confusing as in source code,
// because assigning an object literal in externs only makes sense when
// defining a namespace or enum.
if (!n.isFromExterns()
&& (jsdoc == null || !jsdoc.isConstant())) {
return false;
}
Node qnameNode;
Node initializer;
if (n.getParent().isVar()) {
qnameNode = n;
initializer = n.getFirstChild();
} else if (n.isExprResult()) {
Node expr = n.getFirstChild();
if (!expr.isAssign() || !expr.getFirstChild().isGetProp()) {
return false;
}
qnameNode = expr.getFirstChild();
initializer = expr.getLastChild();
} else if (n.isGetProp()) {
Node parent = n.getParent();
if (!parent.isAssign() || !parent.getParent().isExprResult()) {
return false;
}
qnameNode = n;
initializer = parent.getLastChild();
} else {
return false;
}
if (initializer == null || qnameNode == null) {
return false;
}
if (initializer.isObjectLit()) {
return true;
}
return initializer.isOr()
&& qnameNode.matchesQualifiedName(initializer.getFirstChild())
&& initializer.getLastChild().isObjectLit();
}
/**
* Creates an EXPR_RESULT.
*
* @param child The expression itself.
* @return Newly created EXPR node with the child as subexpression.
*/
static Node newExpr(Node child) {
return IR.exprResult(child).srcref(child);
}
/**
* Returns true if the node may create new mutable state, or change existing
* state.
*
* @see XKCD Cartoon
*/
static boolean mayEffectMutableState(Node n) {
return mayEffectMutableState(n, null);
}
static boolean mayEffectMutableState(Node n, AbstractCompiler compiler) {
return checkForStateChangeHelper(n, true, compiler);
}
/**
* Returns true if the node which may have side effects when executed.
* This version default to the "safe" assumptions when the compiler object is not
* provided (RegExp have side-effects, etc).
*/
public static boolean mayHaveSideEffects(Node n) {
return mayHaveSideEffects(n, null);
}
public static boolean mayHaveSideEffects(Node n, AbstractCompiler compiler) {
return checkForStateChangeHelper(n, false, compiler);
}
/**
* Returns true if some node in n's subtree changes application state.
* If {@code checkForNewObjects} is true, we assume that newly created
* mutable objects (like object literals) change state. Otherwise, we assume
* that they have no side effects.
*/
private static boolean checkForStateChangeHelper(
Node n, boolean checkForNewObjects, AbstractCompiler compiler) {
// Rather than id which ops may have side effects, id the ones
// that we know to be safe
switch (n.getType()) {
// other side-effect free statements and expressions
// Throws are by definition side effects, and yields are similar.
case Token.THROW:
case Token.YIELD:
return true;
case Token.OBJECTLIT:
if (checkForNewObjects) {
return true;
}
for (Node key = n.getFirstChild(); key != null; key = key.getNext()) {
for (Node c = key.getFirstChild(); c != null; c = c.getNext()) {
if (checkForStateChangeHelper(c, checkForNewObjects, compiler)) {
return true;
}
}
}
return false;
case Token.ARRAYLIT:
case Token.REGEXP:
if (checkForNewObjects) {
return true;
}
break;
case Token.VAR: // empty var statement (no declaration)
case Token.NAME: // variable by itself
if (n.getFirstChild() != null) {
return true;
}
break;
case Token.FUNCTION:
// Function expressions don't have side-effects, but function
// declarations change the namespace. Either way, we don't need to
// check the children, since they aren't executed at declaration time.
return checkForNewObjects || !isFunctionExpression(n);
case Token.CLASS:
// Must also check the extends clause for side effects.
return checkForNewObjects || !isClassExpression(n)
|| checkForStateChangeHelper(n.getSecondChild(), checkForNewObjects, compiler);
case Token.NEW:
if (checkForNewObjects) {
return true;
}
if (!constructorCallHasSideEffects(n)) {
// loop below will see if the constructor parameters have
// side-effects
break;
}
return true;
case Token.CALL:
// calls to functions that have no side effects have the no
// side effect property set.
if (!functionCallHasSideEffects(n, compiler)) {
// loop below will see if the function parameters have
// side-effects
break;
}
return true;
case Token.TAGGED_TEMPLATELIT:
return functionCallHasSideEffects(n, compiler);
case Token.CAST:
case Token.AND:
case Token.BLOCK:
case Token.EXPR_RESULT:
case Token.HOOK:
case Token.IF:
case Token.IN:
case Token.PARAM_LIST:
case Token.NUMBER:
case Token.OR:
case Token.THIS:
case Token.TRUE:
case Token.FALSE:
case Token.NULL:
case Token.STRING:
case Token.STRING_KEY:
case Token.SWITCH:
case Token.TEMPLATELIT_SUB:
case Token.TRY:
case Token.EMPTY:
case Token.TEMPLATELIT:
break;
default:
if (isSimpleOperator(n)) {
break;
}
if (isAssignmentOp(n)) {
Node assignTarget = n.getFirstChild();
if (assignTarget.isName()) {
return true;
}
// Assignments will have side effects if
// a) The RHS has side effects, or
// b) The LHS has side effects, or
// c) A name on the LHS will exist beyond the life of this statement.
if (checkForStateChangeHelper(
n.getFirstChild(), checkForNewObjects, compiler) ||
checkForStateChangeHelper(
n.getLastChild(), checkForNewObjects, compiler)) {
return true;
}
if (isGet(assignTarget)) {
// If the object being assigned to is a local object, don't
// consider this a side-effect as it can't be referenced
// elsewhere. Don't do this recursively as the property might
// be an alias of another object, unlike a literal below.
Node current = assignTarget.getFirstChild();
if (evaluatesToLocalValue(current)) {
return false;
}
// A literal value as defined by "isLiteralValue" is guaranteed
// not to be an alias, or any components which are aliases of
// other objects.
// If the root object is a literal don't consider this a
// side-effect.
while (isGet(current)) {
current = current.getFirstChild();
}
return !isLiteralValue(current, true);
} else {
// TODO(johnlenz): remove this code and make this an exception. This
// is here only for legacy reasons, the AST is not valid but
// preserve existing behavior.
return !isLiteralValue(assignTarget, true);
}
}
return true;
}
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (checkForStateChangeHelper(c, checkForNewObjects, compiler)) {
return true;
}
}
return false;
}
/**
* Do calls to this constructor have side effects?
*
* @param callNode - constructor call node
*/
static boolean constructorCallHasSideEffects(Node callNode) {
if (!callNode.isNew()) {
throw new IllegalStateException(
"Expected NEW node, got " + Token.name(callNode.getType()));
}
if (callNode.isNoSideEffectsCall()) {
return false;
}
if (callNode.isOnlyModifiesArgumentsCall() &&
allArgsUnescapedLocal(callNode)) {
return false;
}
Node nameNode = callNode.getFirstChild();
return !nameNode.isName() || !CONSTRUCTORS_WITHOUT_SIDE_EFFECTS.contains(nameNode.getString());
}
// A list of built-in object creation or primitive type cast functions that
// can also be called as constructors but lack side-effects.
// TODO(johnlenz): consider adding an extern annotation for this.
private static final Set BUILTIN_FUNCTIONS_WITHOUT_SIDEEFFECTS =
ImmutableSet.of(
"Object", "Array", "String", "Number", "Boolean", "RegExp", "Error");
private static final Set OBJECT_METHODS_WITHOUT_SIDEEFFECTS =
ImmutableSet.of("toString", "valueOf");
private static final Set REGEXP_METHODS =
ImmutableSet.of("test", "exec");
private static final Set STRING_REGEXP_METHODS =
ImmutableSet.of("match", "replace", "search", "split");
/**
* Returns true if calls to this function have side effects.
*
* @param callNode - function call node
*/
static boolean functionCallHasSideEffects(Node callNode) {
return functionCallHasSideEffects(callNode, null);
}
/**
* Returns true if calls to this function have side effects.
*
* @param callNode The call node to inspected.
* @param compiler A compiler object to provide program state changing
* context information. Can be null.
*/
static boolean functionCallHasSideEffects(
Node callNode, @Nullable AbstractCompiler compiler) {
Preconditions.checkState(callNode.isCall() || callNode.isTaggedTemplateLit(), callNode);
if (callNode.isNoSideEffectsCall()) {
return false;
}
if (callNode.isOnlyModifiesArgumentsCall()
&& allArgsUnescapedLocal(callNode)) {
return false;
}
Node nameNode = callNode.getFirstChild();
// Built-in functions with no side effects.
if (nameNode.isName()) {
String name = nameNode.getString();
if (BUILTIN_FUNCTIONS_WITHOUT_SIDEEFFECTS.contains(name)) {
return false;
}
} else if (nameNode.isGetProp()) {
if (callNode.hasOneChild()
&& OBJECT_METHODS_WITHOUT_SIDEEFFECTS.contains(
nameNode.getLastChild().getString())) {
return false;
}
if (callNode.isOnlyModifiesThisCall()
&& evaluatesToLocalValue(nameNode.getFirstChild())) {
return false;
}
// Many common Math functions have no side-effects.
// TODO(nicksantos): This is a terrible terrible hack, until
// I create a definitionProvider that understands namespacing.
if (nameNode.getFirstChild().isName() && nameNode.isQualifiedName()
&& nameNode.getFirstChild().getString().equals("Math")) {
switch(nameNode.getLastChild().getString()) {
case "abs":
case "acos":
case "acosh":
case "asin":
case "asinh":
case "atan":
case "atanh":
case "atan2":
case "cbrt":
case "ceil":
case "cos":
case "cosh":
case "exp":
case "expm1":
case "floor":
case "hypot":
case "log":
case "log10":
case "log1p":
case "log2":
case "max":
case "min":
case "pow":
case "round":
case "sign":
case "sin":
case "sinh":
case "sqrt":
case "tan":
case "tanh":
case "trunc":
return false;
case "random":
return !callNode.hasOneChild(); // no parameters
}
}
if (compiler != null && !compiler.hasRegExpGlobalReferences()) {
if (nameNode.getFirstChild().isRegExp()
&& REGEXP_METHODS.contains(nameNode.getLastChild().getString())) {
return false;
} else if (nameNode.getFirstChild().isString()) {
String method = nameNode.getLastChild().getString();
Node param = nameNode.getNext();
if (param != null) {
if (param.isString()) {
if (STRING_REGEXP_METHODS.contains(method)) {
return false;
}
} else if (param.isRegExp()) {
if ("replace".equals(method)) {
// Assume anything but a string constant has side-effects
return !param.getNext().isString();
} else if (STRING_REGEXP_METHODS.contains(method)) {
return false;
}
}
}
}
}
}
return true;
}
/**
* @return Whether the call has a local result.
*/
static boolean callHasLocalResult(Node n) {
Preconditions.checkState(n.isCall(), n);
return (n.getSideEffectFlags() & Node.FLAG_LOCAL_RESULTS) > 0;
}
/**
* @return Whether the new has a local result.
*/
static boolean newHasLocalResult(Node n) {
Preconditions.checkState(n.isNew(), n);
return n.isOnlyModifiesThisCall();
}
/**
* Returns true if the current node's type implies side effects.
*
* This is a non-recursive version of the may have side effects
* check; used to check wherever the current node's type is one of
* the reason's why a subtree has side effects.
*/
static boolean nodeTypeMayHaveSideEffects(Node n) {
return nodeTypeMayHaveSideEffects(n, null);
}
static boolean nodeTypeMayHaveSideEffects(Node n, AbstractCompiler compiler) {
if (isAssignmentOp(n)) {
return true;
}
switch(n.getType()) {
case Token.DELPROP:
case Token.DEC:
case Token.INC:
case Token.YIELD:
case Token.THROW:
return true;
case Token.CALL:
return NodeUtil.functionCallHasSideEffects(n, compiler);
case Token.NEW:
return NodeUtil.constructorCallHasSideEffects(n);
case Token.NAME:
// A variable definition.
return n.hasChildren();
default:
return false;
}
}
static boolean allArgsUnescapedLocal(Node callOrNew) {
for (Node arg = callOrNew.getSecondChild();
arg != null; arg = arg.getNext()) {
if (!evaluatesToLocalValue(arg)) {
return false;
}
}
return true;
}
/**
* @return Whether the tree can be affected by side-effects or
* has side-effects.
*/
static boolean canBeSideEffected(Node n) {
Set emptySet = Collections.emptySet();
return canBeSideEffected(n, emptySet, null);
}
/**
* @param knownConstants A set of names known to be constant value at
* node 'n' (such as locals that are last written before n can execute).
* @return Whether the tree can be affected by side-effects or
* has side-effects.
*/
// TODO(nick): Get rid of the knownConstants argument in favor of using
// scope with InferConsts.
static boolean canBeSideEffected(
Node n, Set knownConstants, Scope scope) {
switch (n.getType()) {
case Token.YIELD:
case Token.CALL:
case Token.NEW:
// Function calls or constructor can reference changed values.
// TODO(johnlenz): Add some mechanism for determining that functions
// are unaffected by side effects.
return true;
case Token.NAME:
// Non-constant names values may have been changed.
return !isConstantVar(n, scope)
&& !knownConstants.contains(n.getString());
// Properties on constant NAMEs can still be side-effected.
case Token.GETPROP:
case Token.GETELEM:
return true;
case Token.FUNCTION:
// Function expression are not changed by side-effects,
// and function declarations are not part of expressions.
Preconditions.checkState(isFunctionExpression(n));
return false;
}
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (canBeSideEffected(c, knownConstants, scope)) {
return true;
}
}
return false;
}
/*
* 0 comma ,
* 1 assignment = += -= *= /= %= <<= >>= >>>= &= ^= |=
* 2 conditional ?:
* 3 logical-or ||
* 4 logical-and &&
* 5 bitwise-or |
* 6 bitwise-xor ^
* 7 bitwise-and &
* 8 equality == !=
* 9 relational < <= > >=
* 10 bitwise shift << >> >>>
* 11 addition/subtraction + -
* 12 multiply/divide * / %
* 13 negation/increment ! ~ - ++ --
* 14 call, member () [] .
*/
static int precedence(int type) {
switch (type) {
case Token.COMMA: return 0;
case Token.ASSIGN_BITOR:
case Token.ASSIGN_BITXOR:
case Token.ASSIGN_BITAND:
case Token.ASSIGN_LSH:
case Token.ASSIGN_RSH:
case Token.ASSIGN_URSH:
case Token.ASSIGN_ADD:
case Token.ASSIGN_SUB:
case Token.ASSIGN_MUL:
case Token.ASSIGN_DIV:
case Token.ASSIGN_MOD:
case Token.ASSIGN: return 1;
case Token.YIELD: return 2;
case Token.HOOK: return 3; // ?: operator
case Token.OR: return 4;
case Token.AND: return 5;
case Token.BITOR: return 6;
case Token.BITXOR: return 7;
case Token.BITAND: return 8;
case Token.EQ:
case Token.NE:
case Token.SHEQ:
case Token.SHNE: return 9;
case Token.LT:
case Token.GT:
case Token.LE:
case Token.GE:
case Token.INSTANCEOF:
case Token.IN: return 10;
case Token.LSH:
case Token.RSH:
case Token.URSH: return 11;
case Token.SUB:
case Token.ADD: return 12;
case Token.MUL:
case Token.MOD:
case Token.DIV: return 13;
case Token.INC:
case Token.DEC:
case Token.NEW:
case Token.DELPROP:
case Token.TYPEOF:
case Token.VOID:
case Token.NOT:
case Token.BITNOT:
case Token.POS:
case Token.NEG: return 14;
case Token.CALL:
case Token.GETELEM:
case Token.GETPROP:
// Data values
case Token.ARRAYLIT:
case Token.ARRAY_PATTERN:
case Token.DEFAULT_VALUE:
case Token.DESTRUCTURING_LHS:
case Token.EMPTY: // TODO(johnlenz): remove this.
case Token.FALSE:
case Token.FUNCTION:
case Token.CLASS:
case Token.NAME:
case Token.NULL:
case Token.NUMBER:
case Token.OBJECTLIT:
case Token.OBJECT_PATTERN:
case Token.REGEXP:
case Token.REST:
case Token.SPREAD:
case Token.STRING:
case Token.STRING_KEY:
case Token.MEMBER_VARIABLE_DEF:
case Token.INDEX_SIGNATURE:
case Token.CALL_SIGNATURE:
case Token.THIS:
case Token.SUPER:
case Token.TRUE:
case Token.TAGGED_TEMPLATELIT:
case Token.TEMPLATELIT:
// Tokens from the type declaration AST
case Token.UNION_TYPE:
return 15;
case Token.FUNCTION_TYPE:
return 16;
case Token.ARRAY_TYPE:
case Token.PARAMETERIZED_TYPE:
return 17;
case Token.STRING_TYPE:
case Token.NUMBER_TYPE:
case Token.BOOLEAN_TYPE:
case Token.ANY_TYPE:
case Token.RECORD_TYPE:
case Token.NULLABLE_TYPE:
case Token.NAMED_TYPE:
case Token.UNDEFINED_TYPE:
case Token.GENERIC_TYPE:
return 18;
case Token.CAST:
return 19;
default:
throw new IllegalStateException("Unknown precedence for "
+ Token.name(type) + " (type " + type + ")");
}
}
public static boolean isUndefined(Node n) {
switch (n.getType()) {
case Token.VOID:
return true;
case Token.NAME:
return n.getString().equals("undefined");
}
return false;
}
public static boolean isNullOrUndefined(Node n) {
return n.isNull() || isUndefined(n);
}
static final Predicate IMMUTABLE_PREDICATE = new Predicate() {
@Override
public boolean apply(Node n) {
return isImmutableValue(n);
}
};
static boolean isImmutableResult(Node n) {
return allResultsMatch(n, IMMUTABLE_PREDICATE);
}
/**
* Apply the supplied predicate against
* all possible result Nodes of the expression.
*/
static boolean allResultsMatch(Node n, Predicate p) {
switch (n.getType()) {
case Token.CAST:
return allResultsMatch(n.getFirstChild(), p);
case Token.ASSIGN:
case Token.COMMA:
return allResultsMatch(n.getLastChild(), p);
case Token.AND:
case Token.OR:
return allResultsMatch(n.getFirstChild(), p)
&& allResultsMatch(n.getLastChild(), p);
case Token.HOOK:
return allResultsMatch(n.getSecondChild(), p)
&& allResultsMatch(n.getLastChild(), p);
default:
return p.apply(n);
}
}
enum ValueType {
UNDETERMINED,
NULL,
VOID,
NUMBER,
STRING,
BOOLEAN,
OBJECT
}
/**
* Apply the supplied predicate against
* all possible result Nodes of the expression.
*/
static ValueType getKnownValueType(Node n) {
switch (n.getType()) {
case Token.CAST:
return getKnownValueType(n.getFirstChild());
case Token.ASSIGN:
case Token.COMMA:
return getKnownValueType(n.getLastChild());
case Token.AND:
case Token.OR:
return and(
getKnownValueType(n.getFirstChild()),
getKnownValueType(n.getLastChild()));
case Token.HOOK:
return and(
getKnownValueType(n.getSecondChild()),
getKnownValueType(n.getLastChild()));
case Token.ADD: {
ValueType last = getKnownValueType(n.getLastChild());
if (last == ValueType.STRING) {
return ValueType.STRING;
}
ValueType first = getKnownValueType(n.getFirstChild());
if (first == ValueType.STRING) {
return ValueType.STRING;
}
// There are some pretty weird cases for object types:
// {} + [] === "0"
// [] + {} ==== "[object Object]"
if (first == ValueType.OBJECT || last == ValueType.OBJECT) {
return ValueType.UNDETERMINED;
}
if (!mayBeString(first) && !mayBeString(last)) {
// ADD used with compilations of null, undefined, boolean and number always result
// in numbers.
return ValueType.NUMBER;
}
// There are some pretty weird cases for object types:
// {} + [] === "0"
// [] + {} ==== "[object Object]"
return ValueType.UNDETERMINED;
}
case Token.ASSIGN_ADD: {
ValueType last = getKnownValueType(n.getLastChild());
if (last == ValueType.STRING) {
return ValueType.STRING;
}
return ValueType.UNDETERMINED;
}
case Token.NAME:
String name = n.getString();
if (name.equals("undefined")) {
return ValueType.VOID;
}
if (name.equals("NaN")) {
return ValueType.NUMBER;
}
if (name.equals("Infinity")) {
return ValueType.NUMBER;
}
return ValueType.UNDETERMINED;
case Token.ASSIGN_BITOR:
case Token.ASSIGN_BITXOR:
case Token.ASSIGN_BITAND:
case Token.ASSIGN_LSH:
case Token.ASSIGN_RSH:
case Token.ASSIGN_URSH:
case Token.ASSIGN_SUB:
case Token.ASSIGN_MUL:
case Token.ASSIGN_DIV:
case Token.ASSIGN_MOD:
case Token.BITNOT:
case Token.BITOR:
case Token.BITXOR:
case Token.BITAND:
case Token.LSH:
case Token.RSH:
case Token.URSH:
case Token.SUB:
case Token.MUL:
case Token.MOD:
case Token.DIV:
case Token.INC:
case Token.DEC:
case Token.POS:
case Token.NEG:
case Token.NUMBER:
return ValueType.NUMBER;
// Primitives
case Token.TRUE:
case Token.FALSE:
// Comparisons
case Token.EQ:
case Token.NE:
case Token.SHEQ:
case Token.SHNE:
case Token.LT:
case Token.GT:
case Token.LE:
case Token.GE:
// Queries
case Token.IN:
case Token.INSTANCEOF:
// Inversion
case Token.NOT:
// delete operator returns a boolean.
case Token.DELPROP:
return ValueType.BOOLEAN;
case Token.TYPEOF:
case Token.STRING:
return ValueType.STRING;
case Token.NULL:
return ValueType.NULL;
case Token.VOID:
return ValueType.VOID;
case Token.FUNCTION:
case Token.NEW:
case Token.ARRAYLIT:
case Token.OBJECTLIT:
case Token.REGEXP:
return ValueType.OBJECT;
default:
return ValueType.UNDETERMINED;
}
}
static ValueType and(ValueType a, ValueType b) {
return (a == b) ? a : ValueType.UNDETERMINED;
}
/**
* Returns true if the result of node evaluation is always a number
*/
public static boolean isNumericResult(Node n) {
return getKnownValueType(n) == ValueType.NUMBER;
}
/**
* @return Whether the result of node evaluation is always a boolean
*/
public static boolean isBooleanResult(Node n) {
return getKnownValueType(n) == ValueType.BOOLEAN;
}
/**
* @return Whether the result of node evaluation is always a string
*/
public static boolean isStringResult(Node n) {
return getKnownValueType(n) == ValueType.STRING;
}
/**
* @return Whether the result of node evaluation is always an object
*/
public static boolean isObjectResult(Node n) {
return getKnownValueType(n) == ValueType.OBJECT;
}
static boolean mayBeString(Node n) {
return mayBeString(n, false);
}
/**
* Return if the node is possibly a string.
*
* @param n The node.
* @param useType If true and the node has a primitive type, return true if that type is string
* and false otherwise.
* @return Whether the results is possibly a string.
*/
static boolean mayBeString(Node n, boolean useType) {
if (useType) {
JSType type = n.getJSType();
if (type != null) {
if (type.isStringValueType()) {
return true;
} else if (type.isNumberValueType() || type.isBooleanValueType() || type.isNullType()
|| type.isVoidType()) {
return false;
}
}
}
return mayBeString(getKnownValueType(n));
}
/**
* @return Whether the results is possibly a string, this includes Objects which may implicitly
* be converted to a string.
*/
static boolean mayBeString(ValueType type) {
switch (type) {
case BOOLEAN:
case NULL:
case NUMBER:
case VOID:
return false;
case OBJECT:
case STRING:
case UNDETERMINED:
return true;
default:
throw new IllegalStateException("unexpected");
}
}
static boolean mayBeObject(Node n) {
return mayBeObject(getKnownValueType(n));
}
static boolean mayBeObject(ValueType type) {
switch (type) {
case BOOLEAN:
case NULL:
case NUMBER:
case STRING:
case VOID:
return false;
case OBJECT:
case UNDETERMINED:
return true;
default:
throw new IllegalStateException("unexpected");
}
}
/**
* Returns true if the operator is associative.
* e.g. (a * b) * c = a * (b * c)
* Note: "+" is not associative because it is also the concatenation
* for strings. e.g. "a" + (1 + 2) is not "a" + 1 + 2
*/
static boolean isAssociative(int type) {
switch (type) {
case Token.MUL:
case Token.AND:
case Token.OR:
case Token.BITOR:
case Token.BITXOR:
case Token.BITAND:
return true;
default:
return false;
}
}
/**
* Returns true if the operator is commutative.
* e.g. (a * b) * c = c * (b * a)
* Note 1: "+" is not commutative because it is also the concatenation
* for strings. e.g. "a" + (1 + 2) is not "a" + 1 + 2
* Note 2: only operations on literals and pure functions are commutative.
*/
static boolean isCommutative(int type) {
switch (type) {
case Token.MUL:
case Token.BITOR:
case Token.BITXOR:
case Token.BITAND:
return true;
default:
return false;
}
}
public static boolean isAssignmentOp(Node n) {
switch (n.getType()){
case Token.ASSIGN:
case Token.ASSIGN_BITOR:
case Token.ASSIGN_BITXOR:
case Token.ASSIGN_BITAND:
case Token.ASSIGN_LSH:
case Token.ASSIGN_RSH:
case Token.ASSIGN_URSH:
case Token.ASSIGN_ADD:
case Token.ASSIGN_SUB:
case Token.ASSIGN_MUL:
case Token.ASSIGN_DIV:
case Token.ASSIGN_MOD:
return true;
}
return false;
}
public static boolean isCompoundAssignementOp(Node n) {
return isAssignmentOp(n) && !n.isAssign();
}
static int getOpFromAssignmentOp(Node n) {
switch (n.getType()){
case Token.ASSIGN_BITOR:
return Token.BITOR;
case Token.ASSIGN_BITXOR:
return Token.BITXOR;
case Token.ASSIGN_BITAND:
return Token.BITAND;
case Token.ASSIGN_LSH:
return Token.LSH;
case Token.ASSIGN_RSH:
return Token.RSH;
case Token.ASSIGN_URSH:
return Token.URSH;
case Token.ASSIGN_ADD:
return Token.ADD;
case Token.ASSIGN_SUB:
return Token.SUB;
case Token.ASSIGN_MUL:
return Token.MUL;
case Token.ASSIGN_DIV:
return Token.DIV;
case Token.ASSIGN_MOD:
return Token.MOD;
}
throw new IllegalArgumentException("Not an assignment op:" + n);
}
static int getAssignOpFromOp(Node n) {
switch (n.getType()) {
case Token.BITOR:
return Token.ASSIGN_BITOR;
case Token.BITXOR:
return Token.ASSIGN_BITXOR;
case Token.BITAND:
return Token.ASSIGN_BITAND;
case Token.LSH:
return Token.ASSIGN_LSH;
case Token.RSH:
return Token.ASSIGN_RSH;
case Token.URSH:
return Token.ASSIGN_URSH;
case Token.ADD:
return Token.ASSIGN_ADD;
case Token.SUB:
return Token.ASSIGN_SUB;
case Token.MUL:
return Token.ASSIGN_MUL;
case Token.DIV:
return Token.ASSIGN_DIV;
case Token.MOD:
return Token.ASSIGN_MOD;
default:
throw new IllegalStateException("Unexpected operator: " + n);
}
}
static boolean hasCorrespondingAssignmentOp(Node n) {
switch (n.getType()) {
case Token.BITOR:
case Token.BITXOR:
case Token.BITAND:
case Token.LSH:
case Token.RSH:
case Token.URSH:
case Token.ADD:
case Token.SUB:
case Token.MUL:
case Token.DIV:
case Token.MOD:
return true;
default:
return false;
}
}
/**
* Determines if the given node contains a function statement or function
* expression.
*/
static boolean containsFunction(Node n) {
return containsType(n, Token.FUNCTION);
}
/**
* Gets the closest ancestor to the given node of the provided type.
*/
static Node getEnclosingType(Node n, final int type) {
return getEnclosingNode(n, new Predicate() {
@Override
public boolean apply(Node n) {
return n.getType() == type;
}
});
}
/**
* Finds the class member function containing the given node.
*/
static Node getEnclosingClassMemberFunction(Node n) {
return getEnclosingType(n, Token.MEMBER_FUNCTION_DEF);
}
/**
* Finds the class containing the given node.
*/
public static Node getEnclosingClass(Node n) {
return getEnclosingType(n, Token.CLASS);
}
/**
* Finds the function containing the given node.
*/
public static Node getEnclosingFunction(Node n) {
return getEnclosingType(n, Token.FUNCTION);
}
/**
* Finds the script containing the given node.
*/
public static Node getEnclosingScript(Node n) {
return getEnclosingType(n, Token.SCRIPT);
}
/**
* Finds the block containing the given node.
*/
public static Node getEnclosingBlock(Node n) {
return getEnclosingType(n, Token.BLOCK);
}
public static boolean isInFunction(Node n) {
return getEnclosingFunction(n) != null;
}
public static Node getEnclosingStatement(Node n) {
return getEnclosingNode(n, isStatement);
}
public static Node getEnclosingNode(Node n, Predicate pred) {
Node curr = n;
while (curr != null && !pred.apply(curr)) {
curr = curr.getParent();
}
return curr;
}
/**
* @return The first property in the objlit or class members, that matches the key.
*/
@Nullable
static Node getFirstPropMatchingKey(Node n, String keyName) {
Preconditions.checkState(n.isObjectLit() || n.isClassMembers());
for (Node keyNode : n.children()) {
if ((keyNode.isStringKey() || keyNode.isMemberFunctionDef())
&& keyNode.getString().equals(keyName)) {
return keyNode.getFirstChild();
}
}
return null;
}
/**
* @return The first computed property in the objlit whose key matches {@code key}.
*/
@Nullable
static Node getFirstComputedPropMatchingKey(Node objlit, Node key) {
Preconditions.checkState(objlit.isObjectLit());
for (Node child : objlit.children()) {
if (child.isComputedProp() && child.getFirstChild().isEquivalentTo(key)) {
return child.getLastChild();
}
}
return null;
}
/**
* Returns true if the shallow scope contains references to 'this' keyword
*/
static boolean referencesThis(Node n) {
Node start = (n.isFunction()) ? n.getLastChild() : n;
return containsType(start, Token.THIS, MATCH_NOT_THIS_BINDING);
}
/**
* Returns true if the current scope contains references to the 'super' keyword.
* Note that if there are classes declared inside the current class, super calls which
* reference those classes are not reported.
*/
static boolean referencesSuper(Node n) {
Node curr = n.getFirstChild();
while (curr != null) {
if (containsType(curr, Token.SUPER, MATCH_NOT_CLASS)) {
return true;
}
curr = curr.getNext();
}
return false;
}
/**
* Is this a GETPROP or GETELEM node?
*/
public static boolean isGet(Node n) {
return n.isGetProp() || n.isGetElem();
}
/**
* Is this node the name of a variable being declared?
*
* @param n The node
* @return True if {@code n} is NAME and {@code parent} is VAR
*/
static boolean isVarDeclaration(Node n) {
// There is no need to verify that parent != null because a NAME node
// always has a parent in a valid parse tree.
return n.isName() && n.getParent().isVar();
}
/**
* Is this node the name of a block-scoped declaration?
* Checks for let, const, class, or block-scoped function declarations.
*
* @param n The node
* @return True if {@code n} is the NAME of a block-scoped declaration.
*/
static boolean isBlockScopedDeclaration(Node n) {
if (n.isName()) {
switch (n.getParent().getType()) {
case Token.LET:
case Token.CONST:
case Token.CATCH:
return true;
case Token.CLASS:
return n.getParent().getFirstChild() == n;
case Token.FUNCTION:
return isBlockScopedFunctionDeclaration(n.getParent());
}
}
return false;
}
/**
* Is this node a name declaration?
*
* @param n The node
* @return True if {@code n} is VAR, LET or CONST
*/
public static boolean isNameDeclaration(Node n) {
return n.isVar() || n.isLet() || n.isConst();
}
/**
* @param n The node
* @return True if {@code n} is a VAR, LET or CONST that contains a
* destructuring pattern.
*/
static boolean isDestructuringDeclaration(Node n) {
if (isNameDeclaration(n)) {
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (c.isDestructuringLhs()) {
return true;
}
}
}
return false;
}
/**
* For an assignment or variable declaration get the assigned value.
* @return The value node representing the new value.
*/
public static Node getAssignedValue(Node n) {
Preconditions.checkState(n.isName(), n);
Node parent = n.getParent();
if (parent.isVar()) {
return n.getFirstChild();
} else if (parent.isAssign() && parent.getFirstChild() == n) {
return n.getNext();
} else {
return null;
}
}
/**
* Is this node an assignment expression statement?
*
* @param n The node
* @return True if {@code n} is EXPR_RESULT and {@code n}'s
* first child is ASSIGN
*/
static boolean isExprAssign(Node n) {
return n.isExprResult()
&& n.getFirstChild().isAssign();
}
/**
* Is this node a call expression statement?
*
* @param n The node
* @return True if {@code n} is EXPR_RESULT and {@code n}'s
* first child is CALL
*/
static boolean isExprCall(Node n) {
return n.isExprResult()
&& n.getFirstChild().isCall();
}
static boolean isVanillaFunction(Node n) {
return n.isFunction() && !n.isArrowFunction();
}
static boolean isVanillaFor(Node n) {
return n.isFor() && n.getChildCount() == 4;
}
static boolean isEnhancedFor(Node n) {
return n.isForOf() || isForIn(n);
}
/**
* @return Whether the node represents a FOR-IN loop.
*/
public static boolean isForIn(Node n) {
return n.isFor() && n.getChildCount() == 3;
}
/**
* Determines whether the given node is a FOR, DO, or WHILE node.
*/
static boolean isLoopStructure(Node n) {
switch (n.getType()) {
case Token.FOR:
case Token.FOR_OF:
case Token.DO:
case Token.WHILE:
return true;
default:
return false;
}
}
/**
* @param n The node to inspect.
* @return If the node, is a FOR, WHILE, or DO, it returns the node for
* the code BLOCK, null otherwise.
*/
static Node getLoopCodeBlock(Node n) {
switch (n.getType()) {
case Token.FOR:
case Token.FOR_OF:
case Token.WHILE:
return n.getLastChild();
case Token.DO:
return n.getFirstChild();
default:
return null;
}
}
/**
* @return Whether the specified node has a loop parent that
* is within the current scope.
*/
static boolean isWithinLoop(Node n) {
for (Node parent : n.getAncestors()) {
if (NodeUtil.isLoopStructure(parent)) {
return true;
}
if (parent.isFunction()) {
break;
}
}
return false;
}
/**
* Determines whether the given node is a FOR, DO, WHILE, WITH, or IF node.
*/
public static boolean isControlStructure(Node n) {
switch (n.getType()) {
case Token.FOR:
case Token.FOR_OF:
case Token.DO:
case Token.WHILE:
case Token.WITH:
case Token.IF:
case Token.LABEL:
case Token.TRY:
case Token.CATCH:
case Token.SWITCH:
case Token.CASE:
case Token.DEFAULT_CASE:
return true;
default:
return false;
}
}
/**
* Determines whether the given node is code node for FOR, DO,
* WHILE, WITH, or IF node.
*/
static boolean isControlStructureCodeBlock(Node parent, Node n) {
switch (parent.getType()) {
case Token.DO:
return parent.getFirstChild() == n;
case Token.TRY:
return parent.getFirstChild() == n || parent.getLastChild() == n;
case Token.FOR:
case Token.FOR_OF:
case Token.WHILE:
case Token.LABEL:
case Token.WITH:
case Token.CATCH:
return parent.getLastChild() == n;
case Token.IF:
case Token.SWITCH:
case Token.CASE:
return parent.getFirstChild() != n;
case Token.DEFAULT_CASE:
return true;
default:
Preconditions.checkState(isControlStructure(parent));
return false;
}
}
/**
* Gets the condition of an ON_TRUE / ON_FALSE CFG edge.
* @param n a node with an outgoing conditional CFG edge
* @return the condition node or null if the condition is not obviously a node
*/
static Node getConditionExpression(Node n) {
switch (n.getType()) {
case Token.IF:
case Token.WHILE:
return n.getFirstChild();
case Token.DO:
return n.getLastChild();
case Token.FOR:
return NodeUtil.isForIn(n) ? null : n.getSecondChild();
case Token.FOR_OF:
case Token.CASE:
return null;
}
throw new IllegalArgumentException(n + " does not have a condition.");
}
/**
* @return Whether the node is of a type that contain other statements.
*/
public static boolean isStatementBlock(Node n) {
return n.isScript() || n.isBlock();
}
/**
* A block scope is created by a non-synthetic block node, a for loop node,
* or a for-of loop node.
*
* Note: for functions, we use two separate scopes for parameters and
* declarations in the body. We need to make sure default parameters cannot
* reference var / function declarations in the body.
*
* @return Whether the node creates a block scope.
*/
static boolean createsBlockScope(Node n) {
switch (n.getType()) {
case Token.BLOCK:
// Don't create block scope for synthetic blocks, or the one contained in a CATCH.
if (n.isSyntheticBlock()
|| n.getParent() == null || n.getGrandparent() == null
|| n.getParent().isCatch()) {
return false;
}
return true;
case Token.FOR:
case Token.FOR_OF:
case Token.SWITCH:
case Token.CLASS:
return true;
}
return false;
}
static boolean isValidCfgRoot(Node n) {
switch (n.getType()) {
case Token.FUNCTION:
case Token.SCRIPT:
return true;
case Token.BLOCK:
// Only valid for top level synthetic block
if (n.getParent() == null || n.getGrandparent() == null) {
return true;
}
default:
return false;
}
}
/**
* @return Whether the node is used as a statement.
*/
public static boolean isStatement(Node n) {
return isStatementParent(n.getParent());
}
private static final Predicate isStatement = new Predicate() {
@Override
public boolean apply(Node n) {
return isStatement(n);
}
};
static boolean isStatementParent(Node parent) {
// It is not possible to determine definitely if a node is a statement
// or not if it is not part of the AST. A FUNCTION node can be
// either part of an expression or a statement.
Preconditions.checkState(parent != null);
switch (parent.getType()) {
case Token.SCRIPT:
case Token.BLOCK:
case Token.LABEL:
case Token.NAMESPACE_ELEMENTS: // The body of TypeScript namespace is also a statement parent
return true;
default:
return false;
}
}
private static boolean isDeclarationParent(Node parent) {
switch (parent.getType()) {
case Token.DECLARE:
case Token.EXPORT:
return true;
default:
return isStatementParent(parent);
}
}
/** Whether the node is part of a switch statement. */
static boolean isSwitchCase(Node n) {
return n.isCase() || n.isDefaultCase();
}
/**
* @return Whether the name is a reference to a variable, function or
* function parameter (not a label or a empty function expression name).
*/
static boolean isReferenceName(Node n) {
return n.isName() && !n.getString().isEmpty();
}
/** Whether the child node is the FINALLY block of a try. */
static boolean isTryFinallyNode(Node parent, Node child) {
return parent.isTry() && parent.getChildCount() == 3
&& child == parent.getLastChild();
}
/** Whether the node is a CATCH container BLOCK. */
static boolean isTryCatchNodeContainer(Node n) {
Node parent = n.getParent();
return parent.isTry()
&& parent.getSecondChild() == n;
}
// TODO(tbreisacher): Add a method for detecting nodes under es6_runtime.js
static boolean isInSyntheticScript(Node n) {
return n.getSourceFileName() != null && n.getSourceFileName().startsWith(" [synthetic:");
}
/**
* Safely remove children while maintaining a valid node structure.
* In some cases, this is done by removing the parent from the AST as well.
*/
public static void removeChild(Node parent, Node node) {
if (isTryFinallyNode(parent, node)) {
if (NodeUtil.hasCatchHandler(getCatchBlock(parent))) {
// A finally can only be removed if there is a catch.
parent.removeChild(node);
} else {
// Otherwise, only its children can be removed.
node.detachChildren();
}
} else if (node.isCatch()) {
// The CATCH can can only be removed if there is a finally clause.
Node tryNode = node.getGrandparent();
Preconditions.checkState(NodeUtil.hasFinally(tryNode));
node.detachFromParent();
} else if (isTryCatchNodeContainer(node)) {
// The container node itself can't be removed, but the contained CATCH
// can if there is a 'finally' clause
Node tryNode = node.getParent();
Preconditions.checkState(NodeUtil.hasFinally(tryNode));
node.detachChildren();
} else if (node.isBlock()) {
// Simply empty the block. This maintains source location and
// "synthetic"-ness.
node.detachChildren();
} else if (isStatementBlock(parent)
|| isSwitchCase(node)) {
// A statement in a block can simply be removed.
parent.removeChild(node);
} else if (parent.isVar() || parent.isExprResult()) {
if (parent.hasMoreThanOneChild()) {
parent.removeChild(node);
} else {
// Remove the node from the parent, so it can be reused.
parent.removeChild(node);
// This would leave an empty VAR, remove the VAR itself.
removeChild(parent.getParent(), parent);
}
} else if (parent.isLabel()
&& node == parent.getLastChild()) {
// Remove the node from the parent, so it can be reused.
parent.removeChild(node);
// A LABEL without children can not be referred to, remove it.
removeChild(parent.getParent(), parent);
} else if (parent.isFor()
&& parent.getChildCount() == 4) {
// Only Token.FOR can have an Token.EMPTY other control structure
// need something for the condition. Others need to be replaced
// or the structure removed.
parent.replaceChild(node, IR.empty());
} else {
throw new IllegalStateException("Invalid attempt to remove node: " + node + " of " + parent);
}
}
/**
* Add a finally block if one does not exist.
*/
static void maybeAddFinally(Node tryNode) {
Preconditions.checkState(tryNode.isTry());
if (!NodeUtil.hasFinally(tryNode)) {
tryNode.addChildrenToBack(IR.block().srcref(tryNode));
}
}
/**
* Merge a block with its parent block.
* @return Whether the block was removed.
*/
public static boolean tryMergeBlock(Node block) {
Preconditions.checkState(block.isBlock());
Node parent = block.getParent();
// Try to remove the block if its parent is a block/script or if its
// parent is label and it has exactly one child.
if (isStatementBlock(parent)) {
Node previous = block;
while (block.hasChildren()) {
Node child = block.removeFirstChild();
parent.addChildAfter(child, previous);
previous = child;
}
parent.removeChild(block);
return true;
} else {
return false;
}
}
/**
* @param node A node
* @return Whether the call is a NEW or CALL node.
*/
public static boolean isCallOrNew(Node node) {
return node.isCall() || node.isNew();
}
/**
* Return a BLOCK node for the given FUNCTION node.
*/
public static Node getFunctionBody(Node fn) {
Preconditions.checkArgument(fn.isFunction(), fn);
return fn.getLastChild();
}
/**
* Is this node a function declaration? A function declaration is a function
* that has a name that is added to the current scope (i.e. a function that
* is not part of a expression; see {@link #isFunctionExpression}).
*/
public static boolean isFunctionDeclaration(Node n) {
return n.isFunction() && isDeclarationParent(n.getParent());
}
/**
* see {@link #isClassDeclaration}
*/
public static boolean isClassDeclaration(Node n) {
return n.isClass() && isDeclarationParent(n.getParent());
}
/**
* Is this node a hoisted function declaration? A function declaration in the
* scope root is hoisted to the top of the scope.
* See {@link #isFunctionDeclaration}).
*/
public static boolean isHoistedFunctionDeclaration(Node n) {
return isFunctionDeclaration(n)
&& (n.getParent().isScript()
|| n.getGrandparent().isFunction());
}
static boolean isBlockScopedFunctionDeclaration(Node n) {
if (!isFunctionDeclaration(n)) {
return false;
}
Node current = n.getParent();
while (current != null) {
switch (current.getType()) {
case Token.BLOCK:
return !current.getParent().isFunction();
case Token.FUNCTION:
case Token.SCRIPT:
case Token.DECLARE:
case Token.EXPORT:
return false;
default:
Preconditions.checkState(current.isLabel());
current = current.getParent();
}
}
return false;
}
static boolean isFunctionBlock(Node n) {
return n.isBlock() && n.getParent() != null && n.getParent().isFunction();
}
/**
* Is a FUNCTION node an function expression? An function expression is one
* that has either no name or a name that is not added to the current scope.
*
* Some examples of function expressions:
*
* (function () {})
* (function f() {})()
* [ function f() {} ]
* var f = function f() {};
* for (function f() {};;) {}
*
*
* Some examples of functions that are not expressions:
*
* function f() {}
* if (x); else function f() {}
* for (;;) { function f() {} }
*
*
* @param n A node
* @return Whether n is a function used within an expression.
*/
static boolean isFunctionExpression(Node n) {
return n.isFunction() && !isStatement(n);
}
/**
* see {@link #isFunctionExpression}
*
* @param n A node
* @return Whether n is a class used within an expression.
*/
static boolean isClassExpression(Node n) {
return n.isClass() && !isStatement(n);
}
/**
* Returns whether this is a bleeding function (an anonymous named function
* that bleeds into the inner scope).
*/
static boolean isBleedingFunctionName(Node n) {
return n.isName() && !n.getString().isEmpty() &&
isFunctionExpression(n.getParent());
}
/**
* Determines if a node is a function expression that has an empty body.
*
* @param node a node
* @return whether the given node is a function expression that is empty
*/
static boolean isEmptyFunctionExpression(Node node) {
return isFunctionExpression(node) && isEmptyBlock(node.getLastChild());
}
/**
* Determines if a function takes a variable number of arguments by
* looking for references to the "arguments" var_args object.
*/
static boolean isVarArgsFunction(Node function) {
// TODO(johnlenz): rename this function
Preconditions.checkArgument(function.isFunction());
return isNameReferenced(
function.getLastChild(),
"arguments",
MATCH_NOT_THIS_BINDING);
}
/**
* @return Whether node is a call to methodName.
* a.f(...)
* a['f'](...)
*/
static boolean isObjectCallMethod(Node callNode, String methodName) {
if (callNode.isCall()) {
Node functionIndentifyingExpression = callNode.getFirstChild();
if (isGet(functionIndentifyingExpression)) {
Node last = functionIndentifyingExpression.getLastChild();
if (last != null && last.isString()) {
String propName = last.getString();
return (propName.equals(methodName));
}
}
}
return false;
}
/**
* @return Whether the callNode represents an expression in the form of:
* x.call(...)
* x['call'](...)
*/
static boolean isFunctionObjectCall(Node callNode) {
return isObjectCallMethod(callNode, "call");
}
/**
* @return Whether the callNode represents an expression in the form of:
* x.apply(...)
* x['apply'](...)
*/
static boolean isFunctionObjectApply(Node callNode) {
return isObjectCallMethod(callNode, "apply");
}
static boolean isGoogBind(Node n) {
return n.isGetProp() && n.matchesQualifiedName("goog.bind");
}
static boolean isGoogPartial(Node n) {
return n.isGetProp() && n.matchesQualifiedName("goog.partial");
}
// Does not use type info. For example, it returns false for f.bind(...)
// because it cannot know whether f is a function.
static boolean isFunctionBind(Node expr) {
if (!expr.isGetProp()) {
return false;
}
if (isGoogBind(expr) || isGoogPartial(expr)) {
return true;
}
return expr.getFirstChild().isFunction()
&& expr.getLastChild().getString().equals("bind");
}
/**
* Determines whether this node is strictly on the left hand side of an assign
* or var initialization. Notably, this does not include all L-values, only
* statements where the node is used only as an L-value.
*
* @param n The node
* @param parent Parent of the node
* @return True if n is the left hand of an assign
*/
static boolean isVarOrSimpleAssignLhs(Node n, Node parent) {
return (parent.isAssign() && parent.getFirstChild() == n) ||
parent.isVar();
}
/**
* Determines whether this node is used as an L-value. Notice that sometimes
* names are used as both L-values and R-values.
*
* We treat "var x;" and "let x;" as an L-value because it's syntactically similar to
* "var x = undefined", even though it's technically not an L-value. But it kind of makes
* sense if you treat it as "assignment to 'undefined' at the top of the scope".
*
* @param n The node
* @return True if n is an L-value.
*/
public static boolean isLValue(Node n) {
if (!n.isName() && !n.isGetProp() && !n.isGetElem() && !n.isStringKey()) {
return false;
}
Node parent = n.getParent();
if (parent == null) {
return false;
}
return (isAssignmentOp(parent) && parent.getFirstChild() == n)
|| (isForIn(parent) && parent.getFirstChild() == n)
|| isNameDeclaration(parent)
|| (parent.isFunction() && parent.getFirstChild() == n)
|| parent.isRest()
|| (parent.isDefaultValue() && parent.getFirstChild() == n)
|| parent.isDec()
|| parent.isInc()
|| parent.isParamList()
|| parent.isCatch()
|| isImportedName(n)
|| isLhsByDestructuring(n);
}
public static boolean isImportedName(Node n) {
Node parent = n.getParent();
return parent.isImport()
|| parent.isImportSpec() && parent.getLastChild() == n;
}
public static boolean isLhsByDestructuring(Node n) {
Node parent = n.getParent();
if (parent.isDestructuringPattern()
|| (parent.isStringKey() && parent.getParent().isObjectPattern())) {
if (n.isStringKey() && n.hasChildren()) {
return false;
}
return true;
}
return false;
}
/**
* Determines whether a node represents an object literal key
* (e.g. key1 in {key1: value1, key2: value2}).
*
* @param node A node
*/
static boolean isObjectLitKey(Node node) {
switch (node.getType()) {
case Token.STRING_KEY:
case Token.GETTER_DEF:
case Token.SETTER_DEF:
case Token.MEMBER_FUNCTION_DEF:
return true;
}
return false;
}
/**
* Get the name of an object literal key.
*
* @param key A node
*/
static String getObjectLitKeyName(Node key) {
switch (key.getType()) {
case Token.STRING_KEY:
case Token.GETTER_DEF:
case Token.SETTER_DEF:
case Token.MEMBER_FUNCTION_DEF:
return key.getString();
}
throw new IllegalStateException("Unexpected node type: " + key);
}
/**
* Determines whether a node represents an object literal get or set key
* (e.g. key1 in {get key1() {}, set key2(a){}).
*
* @param node A node
*/
static boolean isGetOrSetKey(Node node) {
switch (node.getType()) {
case Token.GETTER_DEF:
case Token.SETTER_DEF:
return true;
}
return false;
}
/**
* Converts an operator's token value (see {@link Token}) to a string
* representation.
*
* @param operator the operator's token value to convert
* @return the string representation or {@code null} if the token value is
* not an operator
*/
public static String opToStr(int operator) {
switch (operator) {
case Token.BITOR:
return "|";
case Token.OR:
return "||";
case Token.BITXOR:
return "^";
case Token.AND:
return "&&";
case Token.BITAND:
return "&";
case Token.SHEQ:
return "===";
case Token.EQ:
return "==";
case Token.NOT:
return "!";
case Token.NE:
return "!=";
case Token.SHNE:
return "!==";
case Token.LSH:
return "<<";
case Token.IN:
return "in";
case Token.LE:
return "<=";
case Token.LT:
return "<";
case Token.URSH:
return ">>>";
case Token.RSH:
return ">>";
case Token.GE:
return ">=";
case Token.GT:
return ">";
case Token.MUL:
return "*";
case Token.DIV:
return "/";
case Token.MOD:
return "%";
case Token.BITNOT:
return "~";
case Token.ADD:
case Token.POS:
return "+";
case Token.SUB:
case Token.NEG:
return "-";
case Token.ASSIGN:
return "=";
case Token.ASSIGN_BITOR:
return "|=";
case Token.ASSIGN_BITXOR:
return "^=";
case Token.ASSIGN_BITAND:
return "&=";
case Token.ASSIGN_LSH:
return "<<=";
case Token.ASSIGN_RSH:
return ">>=";
case Token.ASSIGN_URSH:
return ">>>=";
case Token.ASSIGN_ADD:
return "+=";
case Token.ASSIGN_SUB:
return "-=";
case Token.ASSIGN_MUL:
return "*=";
case Token.ASSIGN_DIV:
return "/=";
case Token.ASSIGN_MOD:
return "%=";
case Token.VOID:
return "void";
case Token.TYPEOF:
return "typeof";
case Token.INSTANCEOF:
return "instanceof";
default:
return null;
}
}
/**
* Converts an operator's token value (see {@link Token}) to a string
* representation or fails.
*
* @param operator the operator's token value to convert
* @return the string representation
* @throws Error if the token value is not an operator
*/
static String opToStrNoFail(int operator) {
String res = opToStr(operator);
if (res == null) {
throw new Error("Unknown op " + operator + ": " +
Token.name(operator));
}
return res;
}
/**
* @return true if n or any of its descendants are of the specified type.
*/
static boolean containsType(Node node,
int type,
Predicate traverseChildrenPred) {
return has(node, new MatchNodeType(type), traverseChildrenPred);
}
/**
* @return true if n or any of its descendants are of the specified type.
*/
public static boolean containsType(Node node, int type) {
return containsType(node, type, Predicates.alwaysTrue());
}
/**
* Given a node tree, finds all the VAR declarations in that tree that are
* not in an inner scope. Then adds a new VAR node at the top of the current
* scope that redeclares them, if necessary.
*/
static void redeclareVarsInsideBranch(Node branch) {
Collection vars = getVarsDeclaredInBranch(branch);
if (vars.isEmpty()) {
return;
}
Node parent = getAddingRoot(branch);
for (Node nameNode : vars) {
Node var = IR.var(
IR.name(nameNode.getString())
.srcref(nameNode))
.srcref(nameNode);
copyNameAnnotations(nameNode, var.getFirstChild());
parent.addChildToFront(var);
}
}
/**
* Copy any annotations that follow a named value.
* @param source
* @param destination
*/
static void copyNameAnnotations(Node source, Node destination) {
if (source.getBooleanProp(Node.IS_CONSTANT_NAME)) {
destination.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
}
/**
* Gets a Node at the top of the current scope where we can add new var
* declarations as children.
*/
private static Node getAddingRoot(Node n) {
Node addingRoot = null;
Node ancestor = n;
while (null != (ancestor = ancestor.getParent())) {
int type = ancestor.getType();
if (type == Token.SCRIPT) {
addingRoot = ancestor;
break;
} else if (type == Token.FUNCTION) {
addingRoot = ancestor.getLastChild();
break;
}
}
// make sure that the adding root looks ok
Preconditions.checkState(addingRoot.isBlock() ||
addingRoot.isScript());
Preconditions.checkState(addingRoot.getFirstChild() == null ||
!addingRoot.getFirstChild().isScript());
return addingRoot;
}
/**
* Creates a node representing a qualified name.
*
* @param name A qualified name (e.g. "foo" or "foo.bar.baz")
* @return A NAME or GETPROP node
*/
public static Node newQName(AbstractCompiler compiler, String name) {
int endPos = name.indexOf('.');
if (endPos == -1) {
return newName(compiler, name);
}
Node node;
String nodeName = name.substring(0, endPos);
if ("this".equals(nodeName)) {
node = IR.thisNode();
} else {
node = newName(compiler, nodeName);
}
int startPos;
do {
startPos = endPos + 1;
endPos = name.indexOf('.', startPos);
String part = (endPos == -1
? name.substring(startPos)
: name.substring(startPos, endPos));
Node propNode = IR.string(part);
if (compiler.getCodingConvention().isConstantKey(part)) {
propNode.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
node = IR.getprop(node, propNode);
} while (endPos != -1);
return node;
}
/**
* Creates a property access on the {@code context} tree.
*/
public static Node newPropertyAccess(AbstractCompiler compiler, Node context, String name) {
Node propNode = IR.getprop(context, IR.string(name));
if (compiler.getCodingConvention().isConstantKey(name)) {
propNode.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
return propNode;
}
/**
* Creates a node representing a qualified name.
*
* @param name A qualified name (e.g. "foo" or "foo.bar.baz")
* @return A VAR node, or an EXPR_RESULT node containing an ASSIGN or NAME node.
*/
public static Node newQNameDeclaration(
AbstractCompiler compiler, String name, Node value, JSDocInfo info) {
Node result;
Node nameNode = newQName(compiler, name);
if (nameNode.isName()) {
result = value == null ? IR.var(nameNode) : IR.var(nameNode, value);
result.setJSDocInfo(info);
} else if (value != null) {
result = IR.exprResult(IR.assign(nameNode, value));
result.getFirstChild().setJSDocInfo(info);
} else {
result = IR.exprResult(nameNode);
result.getFirstChild().setJSDocInfo(info);
}
return result;
}
/**
* Creates a node representing a qualified name, copying over the source
* location information from the basis node and assigning the given original
* name to the node.
*
* @param name A qualified name (e.g. "foo" or "foo.bar.baz")
* @param basisNode The node that represents the name as currently found in
* the AST.
* @param originalName The original name of the item being represented by the
* NAME node. Used for debugging information.
*
* @return A NAME or GETPROP node
*/
static Node newQName(
AbstractCompiler compiler, String name, Node basisNode,
String originalName) {
Node node = newQName(compiler, name);
setDebugInformation(node, basisNode, originalName);
return node;
}
/**
* Gets the root node of a qualified name. Must be either NAME, THIS or SUPER.
*/
static Node getRootOfQualifiedName(Node qName) {
for (Node current = qName; true;
current = current.getFirstChild()) {
if (current.isName() || current.isThis() || current.isSuper()) {
return current;
}
Preconditions.checkState(current.isGetProp());
}
}
/**
* Sets the debug information (source file info and original name)
* on the given node.
*
* @param node The node on which to set the debug information.
* @param basisNode The basis node from which to copy the source file info.
* @param originalName The original name of the node.
*/
static void setDebugInformation(Node node, Node basisNode,
String originalName) {
node.copyInformationFromForTree(basisNode);
node.setOriginalName(originalName);
}
private static Node newName(AbstractCompiler compiler, String name) {
Node nameNode = IR.name(name);
if (compiler.getCodingConvention().isConstant(name)) {
nameNode.putBooleanProp(Node.IS_CONSTANT_NAME, true);
}
return nameNode;
}
/**
* Creates a new node representing an *existing* name, copying over the source
* location information from the basis node.
*
* @param name The name for the new NAME node.
* @param srcref The node that represents the name as currently found in
* the AST.
*
* @return The node created.
*/
static Node newName(AbstractCompiler compiler, String name, Node srcref) {
return newName(compiler, name).srcref(srcref);
}
/**
* Creates a new node representing an *existing* name, copying over the source
* location information from the basis node and assigning the given original
* name to the node.
*
* @param name The name for the new NAME node.
* @param basisNode The node that represents the name as currently found in
* the AST.
* @param originalName The original name of the item being represented by the
* NAME node. Used for debugging information.
*
* @return The node created.
*/
static Node newName(
AbstractCompiler compiler, String name,
Node basisNode, String originalName) {
Node nameNode = newName(compiler, name, basisNode);
nameNode.setOriginalName(originalName);
return nameNode;
}
/** Test if all characters in the string are in the Basic Latin (aka ASCII)
* character set - that they have UTF-16 values equal to or below 0x7f.
* This check can find which identifiers with Unicode characters need to be
* escaped in order to allow resulting files to be processed by non-Unicode
* aware UNIX tools and editors.
* *
* See http://en.wikipedia.org/wiki/Latin_characters_in_Unicode
* for more on Basic Latin.
*
* @param s The string to be checked for ASCII-goodness.
*
* @return True if all characters in the string are in Basic Latin set.
*/
static boolean isLatin(String s) {
int len = s.length();
for (int index = 0; index < len; index++) {
char c = s.charAt(index);
if (c > LARGEST_BASIC_LATIN) {
return false;
}
}
return true;
}
/**
* Determines whether the given name is a valid variable name.
*/
static boolean isValidSimpleName(String name) {
return TokenStream.isJSIdentifier(name) &&
!TokenStream.isKeyword(name) &&
// no Unicode escaped characters - some browsers are less tolerant
// of Unicode characters that might be valid according to the
// language spec.
// Note that by this point, Unicode escapes have been converted
// to UTF-16 characters, so we're only searching for character
// values, not escapes.
isLatin(name);
}
@Deprecated
public static boolean isValidQualifiedName(String name) {
return isValidQualifiedName(LanguageMode.ECMASCRIPT3, name);
}
/**
* Determines whether the given name is a valid qualified name.
*/
public static boolean isValidQualifiedName(LanguageMode mode, String name) {
if (name.endsWith(".") || name.startsWith(".")) {
return false;
}
List parts = Splitter.on('.').splitToList(name);
for (String part : parts) {
if (!isValidPropertyName(mode, part)) {
return false;
}
}
return isValidSimpleName(parts.get(0));
}
/**
* Determines whether the given name can appear on the right side of
* the dot operator. Many properties (like reserved words) cannot, in ES3.
*/
static boolean isValidPropertyName(LanguageMode mode, String name) {
if (isValidSimpleName(name)) {
return true;
} else {
return mode.isEs5OrHigher() && TokenStream.isKeyword(name);
}
}
private static class VarCollector implements Visitor {
final Map vars = new LinkedHashMap<>();
@Override
public void visit(Node n) {
if (n.isName()) {
Node parent = n.getParent();
if (parent != null && parent.isVar()) {
String name = n.getString();
if (!vars.containsKey(name)) {
vars.put(name, n);
}
}
}
}
}
/**
* Retrieves vars declared in the current node tree, excluding descent scopes.
*/
static Collection getVarsDeclaredInBranch(Node root) {
VarCollector collector = new VarCollector();
visitPreOrder(
root,
collector,
MATCH_NOT_FUNCTION);
return collector.vars.values();
}
private static void getLhsNodesHelper(Node n, List lhsNodes) {
switch (n.getType()) {
case Token.VAR:
case Token.CONST:
case Token.LET:
case Token.OBJECT_PATTERN:
case Token.ARRAY_PATTERN:
case Token.PARAM_LIST:
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
getLhsNodesHelper(child, lhsNodes);
}
return;
case Token.DESTRUCTURING_LHS:
case Token.DEFAULT_VALUE:
case Token.CATCH:
case Token.REST:
getLhsNodesHelper(n.getFirstChild(), lhsNodes);
return;
case Token.COMPUTED_PROP:
getLhsNodesHelper(n.getLastChild(), lhsNodes);
return;
case Token.STRING_KEY:
if (n.hasChildren()) {
getLhsNodesHelper(n.getLastChild(), lhsNodes);
} else {
Preconditions.checkState(isLValue(n));
lhsNodes.add(n);
}
break;
case Token.NAME:
lhsNodes.add(n);
break;
default:
Preconditions.checkState(n.isEmpty(), "Invalid node in lhs of declaration: %s", n);
}
}
/**
* Retrieves lhs nodes declared in the current declaration.
*/
static Iterable getLhsNodesOfDeclaration(Node declNode) {
Preconditions.checkArgument(
isNameDeclaration(declNode) || declNode.isParamList() || declNode.isCatch(), declNode);
ArrayList lhsNodes = new ArrayList<>();
getLhsNodesHelper(declNode, lhsNodes);
return lhsNodes;
}
/**
* @return {@code true} if the node is a definition with Object.defineProperties
*/
static boolean isObjectDefinePropertiesDefinition(Node n) {
return n.isCall()
&& n.getChildCount() == 3
&& n.getFirstChild().matchesQualifiedName("Object.defineProperties");
}
/**
* @return A list of STRING_KEY properties defined by a Object.defineProperties(o, {...}) call
*/
static Iterable getObjectDefinedPropertiesKeys(Node definePropertiesCall) {
Preconditions.checkArgument(NodeUtil.isObjectDefinePropertiesDefinition(definePropertiesCall));
List properties = new ArrayList<>();
Node objectLiteral = definePropertiesCall.getLastChild();
for (Node key : objectLiteral.children()) {
if (!key.isStringKey()) {
continue;
}
properties.add(key);
}
return properties;
}
/**
* @return {@code true} if the node an assignment to a prototype property of
* some constructor.
*/
public static boolean isPrototypePropertyDeclaration(Node n) {
return isExprAssign(n) &&
isPrototypeProperty(n.getFirstFirstChild());
}
/**
* @return Whether the node represents a qualified prototype property.
*/
static boolean isPrototypeProperty(Node n) {
if (!n.isGetProp()) {
return false;
}
n = n.getFirstChild();
while (n.isGetProp()) {
if (n.getLastChild().getString().equals("prototype")) {
return n.isQualifiedName();
}
n = n.getFirstChild();
}
return false;
}
/**
* @return Whether the node represents a prototype method.
*/
static boolean isPrototypeMethod(Node n) {
if (!n.isFunction()) {
return false;
}
Node assignNode = n.getParent();
if (!assignNode.isAssign()) {
return false;
}
return isPrototypePropertyDeclaration(assignNode.getParent());
}
static boolean isPrototypeAssignment(Node getProp) {
if (!getProp.isGetProp()) {
return false;
}
Node parent = getProp.getParent();
return parent.isAssign() && parent.getFirstChild() == getProp
&& parent.getFirstChild().getLastChild().getString().equals("prototype")
&& parent.getLastChild().isObjectLit();
}
/**
* Determines whether this node is testing for the existence of a property.
* If true, we will not emit warnings about a missing property.
*
* @param propAccess The GETPROP or GETELEM being tested.
*/
static boolean isPropertyTest(AbstractCompiler compiler, Node propAccess) {
Node parent = propAccess.getParent();
switch (parent.getType()) {
case Token.CALL:
return parent.getFirstChild() != propAccess
&& compiler.getCodingConvention().isPropertyTestFunction(parent);
case Token.IF:
case Token.WHILE:
case Token.DO:
case Token.FOR:
return NodeUtil.getConditionExpression(parent) == propAccess;
case Token.INSTANCEOF:
case Token.TYPEOF:
case Token.AND:
case Token.OR:
return true;
case Token.NE:
case Token.SHNE: {
Node other = parent.getFirstChild() == propAccess
? parent.getSecondChild() : parent.getFirstChild();
return isUndefined(other);
}
case Token.HOOK:
return parent.getFirstChild() == propAccess;
case Token.NOT:
return parent.getParent().isOr()
&& parent.getParent().getFirstChild() == parent;
case Token.CAST:
return isPropertyTest(compiler, parent);
}
return false;
}
/**
* @return The class name part of a qualified prototype name.
*/
static Node getPrototypeClassName(Node qName) {
Node cur = qName;
while (cur.isGetProp()) {
if (cur.getLastChild().getString().equals("prototype")) {
return cur.getFirstChild();
} else {
cur = cur.getFirstChild();
}
}
return null;
}
/**
* @return The string property name part of a qualified prototype name.
*/
static String getPrototypePropertyName(Node qName) {
String qNameStr = qName.getQualifiedName();
int prototypeIdx = qNameStr.lastIndexOf(".prototype.");
int memberIndex = prototypeIdx + ".prototype".length() + 1;
return qNameStr.substring(memberIndex);
}
/**
* Create a node for an empty result expression:
* "void 0"
*/
static Node newUndefinedNode(Node srcReferenceNode) {
Node node = IR.voidNode(IR.number(0));
if (srcReferenceNode != null) {
node.copyInformationFromForTree(srcReferenceNode);
}
return node;
}
/**
* Create a VAR node containing the given name and initial value expression.
*/
static Node newVarNode(String name, Node value) {
Node nodeName = IR.name(name);
if (value != null) {
Preconditions.checkState(value.getNext() == null);
nodeName.addChildToBack(value);
nodeName.srcref(value);
}
Node var = IR.var(nodeName).srcref(nodeName);
return var;
}
/**
* A predicate for matching name nodes with the specified node.
*/
private static class MatchNameNode implements Predicate{
final String name;
MatchNameNode(String name){
this.name = name;
}
@Override
public boolean apply(Node n) {
return n.isName() && n.getString().equals(name);
}
}
/**
* A predicate for matching nodes with the specified type.
*/
static class MatchNodeType implements Predicate{
final int type;
MatchNodeType(int type){
this.type = type;
}
@Override
public boolean apply(Node n) {
return n.getType() == type;
}
}
/**
* A predicate for matching var or function declarations.
*/
static class MatchDeclaration implements Predicate {
@Override
public boolean apply(Node n) {
return isFunctionDeclaration(n) || n.isVar();
}
}
/**
* A predicate for matching anything except function nodes.
*/
private static class MatchNotFunction implements Predicate{
@Override
public boolean apply(Node n) {
return !n.isFunction();
}
}
/**
* A predicate for matching anything except class nodes.
*/
private static class MatchNotClass implements Predicate {
@Override
public boolean apply(Node n) {
return !n.isClass();
}
}
static final Predicate MATCH_NOT_FUNCTION = new MatchNotFunction();
static final Predicate MATCH_NOT_CLASS = new MatchNotClass();
static final Predicate MATCH_NOT_THIS_BINDING = new Predicate() {
@Override
public boolean apply(Node n) {
return !NodeUtil.isVanillaFunction(n);
}
};
/**
* A predicate for matching statements without exiting the current scope.
*/
static class MatchShallowStatement implements Predicate{
@Override
public boolean apply(Node n) {
Node parent = n.getParent();
return n.isBlock()
|| (!n.isFunction() && (parent == null
|| isControlStructure(parent)
|| isStatementBlock(parent)));
}
}
/**
* Finds the number of times a type is referenced within the node tree.
*/
static int getNodeTypeReferenceCount(
Node node, int type, Predicate traverseChildrenPred) {
return getCount(node, new MatchNodeType(type), traverseChildrenPred);
}
/**
* Whether a simple name is referenced within the node tree.
*/
static boolean isNameReferenced(Node node,
String name,
Predicate traverseChildrenPred) {
return has(node, new MatchNameNode(name), traverseChildrenPred);
}
/**
* Whether a simple name is referenced within the node tree.
*/
static boolean isNameReferenced(Node node, String name) {
return isNameReferenced(node, name, Predicates.alwaysTrue());
}
/**
* Finds the number of times a simple name is referenced within the node tree.
*/
static int getNameReferenceCount(Node node, String name) {
return getCount(
node, new MatchNameNode(name), Predicates.alwaysTrue());
}
/**
* @return Whether the predicate is true for the node or any of its descendants.
*/
public static boolean has(Node node,
Predicate pred,
Predicate traverseChildrenPred) {
if (pred.apply(node)) {
return true;
}
if (!traverseChildrenPred.apply(node)) {
return false;
}
for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
if (has(c, pred, traverseChildrenPred)) {
return true;
}
}
return false;
}
/**
* @return The number of times the the predicate is true for the node
* or any of its descendants.
*/
public static int getCount(
Node n, Predicate pred, Predicate traverseChildrenPred) {
int total = 0;
if (pred.apply(n)) {
total++;
}
if (traverseChildrenPred.apply(n)) {
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
total += getCount(c, pred, traverseChildrenPred);
}
}
return total;
}
/**
* Interface for use with the visit method.
* @see #visit
*/
public static interface Visitor {
void visit(Node node);
}
/**
* A pre-order traversal, calling Visitor.visit for each child matching
* the predicate.
*/
public static void visitPreOrder(Node node,
Visitor visitor,
Predicate traverseChildrenPred) {
visitor.visit(node);
if (traverseChildrenPred.apply(node)) {
for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
visitPreOrder(c, visitor, traverseChildrenPred);
}
}
}
/**
* A post-order traversal, calling Visitor.visit for each descendant matching
* the predicate.
*/
public static void visitPostOrder(Node node,
Visitor visitor,
Predicate traverseChildrenPred) {
if (traverseChildrenPred.apply(node)) {
for (Node c = node.getFirstChild(); c != null; c = c.getNext()) {
visitPostOrder(c, visitor, traverseChildrenPred);
}
}
visitor.visit(node);
}
/**
* @return Whether a TRY node has a finally block.
*/
static boolean hasFinally(Node n) {
Preconditions.checkArgument(n.isTry());
return n.getChildCount() == 3;
}
/**
* @return The BLOCK node containing the CATCH node (if any)
* of a TRY.
*/
static Node getCatchBlock(Node n) {
Preconditions.checkArgument(n.isTry());
return n.getSecondChild();
}
/**
* @return Whether BLOCK (from a TRY node) contains a CATCH.
* @see NodeUtil#getCatchBlock
*/
static boolean hasCatchHandler(Node n) {
Preconditions.checkArgument(n.isBlock());
return n.hasChildren() && n.getFirstChild().isCatch();
}
/**
* @param fnNode The function.
* @return The Node containing the Function parameters.
*/
public static Node getFunctionParameters(Node fnNode) {
// Function NODE: [ FUNCTION -> NAME, LP -> ARG1, ARG2, ... ]
Preconditions.checkArgument(fnNode.isFunction());
return fnNode.getSecondChild();
}
static boolean isConstantVar(Node node, Scope scope) {
if (isConstantName(node)) {
return true;
}
if (!node.isName() || scope == null) {
return false;
}
Var var = scope.getVar(node.getString());
return var != null && (var.isInferredConst() || var.isConst());
}
/**
* Determines whether a variable is constant:
*
* - In Normalize, any name that matches the
* {@link CodingConvention#isConstant(String)} is annotated with an
* IS_CONSTANT_NAME property.
*
*
* @param node A NAME or STRING node
* @return True if a name node represents a constant variable
*/
static boolean isConstantName(Node node) {
return node.getBooleanProp(Node.IS_CONSTANT_NAME);
}
/** Whether the given name is constant by coding convention. */
static boolean isConstantByConvention(
CodingConvention convention, Node node) {
Node parent = node.getParent();
if (parent.isGetProp() && node == parent.getLastChild()) {
return convention.isConstantKey(node.getString());
} else if (isObjectLitKey(node)) {
return convention.isConstantKey(node.getString());
} else if (node.isName()) {
return convention.isConstant(node.getString());
}
return false;
}
/**
* Temporary function to determine if a node is constant
* in the old or new world. This does not check its inputs
* carefully because it will go away once we switch to the new
* world.
*/
static boolean isConstantDeclaration(
CodingConvention convention, JSDocInfo info, Node node) {
if (info != null && info.isConstant()) {
return true;
}
if (node.getBooleanProp(Node.IS_CONSTANT_VAR)) {
return true;
}
switch (node.getType()) {
case Token.NAME:
return NodeUtil.isConstantByConvention(convention, node);
case Token.GETPROP:
return node.isQualifiedName()
&& NodeUtil.isConstantByConvention(convention, node.getLastChild());
}
return false;
}
static boolean functionHasInlineJsdocs(Node fn) {
if (!fn.isFunction()) {
return false;
}
// Check inline return annotation
if (fn.getFirstChild().getJSDocInfo() != null) {
return true;
}
// Check inline parameter annotations
Node param = fn.getSecondChild().getFirstChild();
while (param != null) {
if (param.getJSDocInfo() != null) {
return true;
}
param = param.getNext();
}
return false;
}
/**
* @param n The node.
* @return The source name property on the node or its ancestors.
*/
public static String getSourceName(Node n) {
String sourceName = null;
while (sourceName == null && n != null) {
sourceName = n.getSourceFileName();
n = n.getParent();
}
return sourceName;
}
/**
* @param n The node.
* @return The source name property on the node or its ancestors.
*/
public static StaticSourceFile getSourceFile(Node n) {
StaticSourceFile sourceName = null;
while (sourceName == null && n != null) {
sourceName = n.getStaticSourceFile();
n = n.getParent();
}
return sourceName;
}
/**
* @param n The node.
* @return The InputId property on the node or its ancestors.
*/
public static InputId getInputId(Node n) {
while (n != null && !n.isScript()) {
n = n.getParent();
}
return (n != null && n.isScript()) ? n.getInputId() : null;
}
/**
* A new CALL node with the "FREE_CALL" set based on call target.
*/
static Node newCallNode(Node callTarget, Node... parameters) {
boolean isFreeCall = !isGet(callTarget);
Node call = IR.call(callTarget);
call.putBooleanProp(Node.FREE_CALL, isFreeCall);
for (Node parameter : parameters) {
call.addChildToBack(parameter);
}
return call;
}
/**
* @return Whether the node is known to be a value that is not referenced
* elsewhere.
*/
static boolean evaluatesToLocalValue(Node value) {
return evaluatesToLocalValue(value, Predicates.alwaysFalse());
}
/**
* @param locals A predicate to apply to unknown local values.
* @return Whether the node is known to be a value that is not a reference
* outside the expression scope.
*/
static boolean evaluatesToLocalValue(Node value, Predicate locals) {
switch (value.getType()) {
case Token.CAST:
return evaluatesToLocalValue(value.getFirstChild(), locals);
case Token.ASSIGN:
// A result that is aliased by a non-local name, is the effectively the
// same as returning a non-local name, but this doesn't matter if the
// value is immutable.
return NodeUtil.isImmutableValue(value.getLastChild())
|| (locals.apply(value)
&& evaluatesToLocalValue(value.getLastChild(), locals));
case Token.COMMA:
return evaluatesToLocalValue(value.getLastChild(), locals);
case Token.AND:
case Token.OR:
return evaluatesToLocalValue(value.getFirstChild(), locals)
&& evaluatesToLocalValue(value.getLastChild(), locals);
case Token.HOOK:
return evaluatesToLocalValue(value.getSecondChild(), locals)
&& evaluatesToLocalValue(value.getLastChild(), locals);
case Token.INC:
case Token.DEC:
return true;
case Token.THIS:
return locals.apply(value);
case Token.NAME:
return isImmutableValue(value) || locals.apply(value);
case Token.GETELEM:
case Token.GETPROP:
// There is no information about the locality of object properties.
return locals.apply(value);
case Token.CALL:
return callHasLocalResult(value)
|| isToStringMethodCall(value)
|| locals.apply(value);
case Token.NEW:
return newHasLocalResult(value)
|| locals.apply(value);
case Token.FUNCTION:
case Token.REGEXP:
case Token.ARRAYLIT:
case Token.OBJECTLIT:
// Literals objects with non-literal children are allowed.
return true;
case Token.DELPROP:
case Token.IN:
// TODO(johnlenz): should IN operator be included in #isSimpleOperator?
return true;
default:
// Other op force a local value:
// x = '' + g (x is now an local string)
// x -= g (x is now an local number)
if (isAssignmentOp(value)
|| isSimpleOperator(value)
|| isImmutableValue(value)) {
return true;
}
throw new IllegalStateException(
"Unexpected expression node" + value +
"\n parent:" + value.getParent());
}
}
/**
* Given the first sibling, this returns the nth
* sibling or null if no such sibling exists.
* This is like "getChildAtIndex" but returns null for non-existent indexes.
*/
private static Node getNthSibling(Node first, int index) {
Node sibling = first;
while (index != 0 && sibling != null) {
sibling = sibling.getNext();
index--;
}
return sibling;
}
/**
* Given the function, this returns the nth
* argument or null if no such parameter exists.
*/
static Node getArgumentForFunction(Node function, int index) {
Preconditions.checkState(function.isFunction());
return getNthSibling(
function.getSecondChild().getFirstChild(), index);
}
/**
* Given the new or call, this returns the nth
* argument of the call or null if no such argument exists.
*/
static Node getArgumentForCallOrNew(Node call, int index) {
Preconditions.checkState(isCallOrNew(call));
return getNthSibling(
call.getSecondChild(), index);
}
/**
* Returns whether this is a target of a call or new.
*/
static boolean isCallOrNewTarget(Node n) {
Node parent = n.getParent();
return parent != null && isCallOrNew(parent) && parent.getFirstChild() == n;
}
static boolean isCallOrNewArgument(Node n) {
Node parent = n.getParent();
return parent != null && isCallOrNew(parent) && parent.getFirstChild() != n;
}
private static boolean isToStringMethodCall(Node call) {
Node getNode = call.getFirstChild();
if (isGet(getNode)) {
Node propNode = getNode.getLastChild();
return propNode.isString() && "toString".equals(propNode.getString());
}
return false;
}
/** Find the best JSDoc for the given node. */
@Nullable
public static JSDocInfo getBestJSDocInfo(Node n) {
Node jsdocNode = getBestJSDocInfoNode(n);
return jsdocNode == null ? null : jsdocNode.getJSDocInfo();
}
@Nullable
static Node getBestJSDocInfoNode(Node n) {
if (n.isExprResult()) {
return getBestJSDocInfoNode(n.getFirstChild());
}
JSDocInfo info = n.getJSDocInfo();
if (info == null) {
Node parent = n.getParent();
if (parent == null || n.isExprResult()) {
return null;
}
if (parent.isName()) {
return getBestJSDocInfoNode(parent);
} else if (parent.isAssign()) {
return getBestJSDocInfoNode(parent);
} else if (isObjectLitKey(parent)) {
return parent;
} else if ((parent.isFunction() || parent.isClass()) && n == parent.getFirstChild()) {
// n is the NAME node of the function/class.
return getBestJSDocInfoNode(parent);
} else if (NodeUtil.isNameDeclaration(parent) && parent.hasOneChild()) {
return parent;
} else if ((parent.isHook() && parent.getFirstChild() != n)
|| parent.isOr()
|| parent.isAnd()
|| (parent.isComma() && parent.getFirstChild() != n)) {
return getBestJSDocInfoNode(parent);
}
}
return n;
}
/** Find the l-value that the given r-value is being assigned to. */
static Node getBestLValue(Node n) {
Node parent = n.getParent();
boolean isFunctionDeclaration = isFunctionDeclaration(n);
if (isFunctionDeclaration) {
return n.getFirstChild();
} else if (parent.isName()) {
return parent;
} else if (parent.isAssign()) {
return parent.getFirstChild();
} else if (isObjectLitKey(parent)) {
return parent;
} else if (
(parent.isHook() && parent.getFirstChild() != n) ||
parent.isOr() ||
parent.isAnd() ||
(parent.isComma() && parent.getFirstChild() != n)) {
return getBestLValue(parent);
} else if (parent.isCast()) {
return getBestLValue(parent);
}
return null;
}
/** Gets the r-value (or intializer) of a node returned by getBestLValue. */
static Node getRValueOfLValue(Node n) {
Node parent = n.getParent();
switch (parent.getType()) {
case Token.ASSIGN:
case Token.ASSIGN_BITOR:
case Token.ASSIGN_BITXOR:
case Token.ASSIGN_BITAND:
case Token.ASSIGN_LSH:
case Token.ASSIGN_RSH:
case Token.ASSIGN_URSH:
case Token.ASSIGN_ADD:
case Token.ASSIGN_SUB:
case Token.ASSIGN_MUL:
case Token.ASSIGN_DIV:
case Token.ASSIGN_MOD:
return n.getNext();
case Token.VAR:
case Token.LET:
case Token.CONST:
case Token.OBJECTLIT:
return n.getFirstChild();
case Token.FUNCTION:
case Token.CLASS:
return parent;
}
return null;
}
/** Get the owner of the given l-value node. */
static Node getBestLValueOwner(@Nullable Node lValue) {
if (lValue == null || lValue.getParent() == null) {
return null;
}
if (isObjectLitKey(lValue)) {
return getBestLValue(lValue.getParent());
} else if (isGet(lValue)) {
return lValue.getFirstChild();
}
return null;
}
/** Get the name of the given l-value node. */
static String getBestLValueName(@Nullable Node lValue) {
if (lValue == null || lValue.getParent() == null) {
return null;
}
if (isObjectLitKey(lValue)) {
Node owner = getBestLValue(lValue.getParent());
if (owner != null) {
String ownerName = getBestLValueName(owner);
if (ownerName != null) {
return ownerName + "." + getObjectLitKeyName(lValue);
}
}
return null;
}
return lValue.getQualifiedName();
}
/**
* @return false iff the result of the expression is not consumed.
*/
static boolean isExpressionResultUsed(Node expr) {
// TODO(johnlenz): consider sharing some code with trySimpleUnusedResult.
Node parent = expr.getParent();
switch (parent.getType()) {
case Token.BLOCK:
case Token.EXPR_RESULT:
return false;
case Token.CAST:
return isExpressionResultUsed(parent);
case Token.HOOK:
case Token.AND:
case Token.OR:
return (expr == parent.getFirstChild()) || isExpressionResultUsed(parent);
case Token.COMMA:
Node grandparent = parent.getParent();
if (grandparent.isCall() &&
parent == grandparent.getFirstChild()) {
// Semantically, a direct call to eval is different from an indirect
// call to an eval. See ECMA-262 S15.1.2.1. So it's OK for the first
// expression to a comma to be a no-op if it's used to indirect
// an eval. This we pretend that this is "used".
if (expr == parent.getFirstChild() &&
parent.getChildCount() == 2 &&
expr.getNext().isName() &&
"eval".equals(expr.getNext().getString())) {
return true;
}
}
return (expr == parent.getFirstChild())
? false : isExpressionResultUsed(parent);
case Token.FOR:
if (!NodeUtil.isForIn(parent)) {
// Only an expression whose result is in the condition part of the
// expression is used.
return (parent.getSecondChild() == expr);
}
break;
}
return true;
}
/**
* @param n The expression to check.
* @return Whether the expression is unconditionally executed only once in the
* containing execution scope.
*/
static boolean isExecutedExactlyOnce(Node n) {
inspect: do {
Node parent = n.getParent();
switch (parent.getType()) {
case Token.IF:
case Token.HOOK:
case Token.AND:
case Token.OR:
if (parent.getFirstChild() != n) {
return false;
}
// other ancestors may be conditional
continue inspect;
case Token.FOR:
if (NodeUtil.isForIn(parent)) {
if (parent.getSecondChild() != n) {
return false;
}
} else {
if (parent.getFirstChild() != n) {
return false;
}
}
// other ancestors may be conditional
continue inspect;
case Token.WHILE:
case Token.DO:
return false;
case Token.TRY:
// Consider all code under a try/catch to be conditionally executed.
if (!hasFinally(parent) || parent.getLastChild() != n) {
return false;
}
continue inspect;
case Token.CASE:
case Token.DEFAULT_CASE:
return false;
case Token.SCRIPT:
case Token.FUNCTION:
// Done, we've reached the scope root.
break inspect;
}
} while ((n = n.getParent()) != null);
return true;
}
/**
* @return An appropriate AST node for the boolean value.
*/
static Node booleanNode(boolean value) {
return value ? IR.trueNode() : IR.falseNode();
}
/**
* @return An appropriate AST node for the double value.
*/
static Node numberNode(double value, Node srcref) {
Node result;
if (Double.isNaN(value)) {
result = IR.name("NaN");
} else if (value == Double.POSITIVE_INFINITY) {
result = IR.name("Infinity");
} else if (value == Double.NEGATIVE_INFINITY) {
result = IR.neg(IR.name("Infinity"));
} else {
result = IR.number(value);
}
if (srcref != null) {
result.srcrefTree(srcref);
}
return result;
}
static boolean isNaN(Node n) {
return (n.isName() && n.getString().equals("NaN")) || (n.getType() == Token.DIV
&& n.getFirstChild().isNumber() && n.getFirstChild().getDouble() == 0
&& n.getLastChild().isNumber() && n.getLastChild().getDouble() == 0);
}
/**
* Given an AST and its copy, map the root node of each scope of main to the
* corresponding root node of clone
*/
public static Map mapMainToClone(Node main, Node clone) {
Preconditions.checkState(main.isEquivalentTo(clone));
Map mtoc = new HashMap<>();
mtoc.put(main, clone);
mtocHelper(mtoc, main, clone);
return mtoc;
}
private static void mtocHelper(Map map, Node main, Node clone) {
if (main.isFunction()) {
map.put(main, clone);
}
Node mchild = main.getFirstChild(), cchild = clone.getFirstChild();
while (mchild != null) {
mtocHelper(map, mchild, cchild);
mchild = mchild.getNext();
cchild = cchild.getNext();
}
}
/** Checks that the scope roots marked as changed have indeed changed */
public static void verifyScopeChanges(Map map, Node main,
boolean verifyUnchangedNodes) {
// compiler is passed only to call compiler.toSource during debugging to see
// mismatches in scopes
// If verifyUnchangedNodes is false, we are comparing the initial AST to the
// final AST. Don't check unmarked nodes b/c they may have been changed by
// non-loopable passes.
// If verifyUnchangedNodes is true, we are comparing the ASTs before & after
// a pass. Check all scope roots.
final Map mtoc = map;
final boolean checkUnchanged = verifyUnchangedNodes;
Node clone = mtoc.get(main);
if (main.getChangeTime() > clone.getChangeTime()) {
Preconditions.checkState(!isEquivalentToExcludingFunctions(main, clone));
} else if (checkUnchanged) {
Preconditions.checkState(isEquivalentToExcludingFunctions(main, clone));
}
visitPreOrder(main,
new Visitor() {
@Override
public void visit(Node n) {
if (n.isFunction() && mtoc.containsKey(n)) {
Node clone = mtoc.get(n);
if (n.getChangeTime() > clone.getChangeTime()) {
Preconditions.checkState(
!isEquivalentToExcludingFunctions(n, clone));
} else if (checkUnchanged) {
Preconditions.checkState(
isEquivalentToExcludingFunctions(n, clone));
}
}
}
},
Predicates.alwaysTrue());
}
static int countAstSizeUpToLimit(Node n, final int limit) {
// Java doesn't allow accessing mutable local variables from another class.
final int[] wrappedSize = {0};
visitPreOrder(
n,
new Visitor() {
@Override
public void visit(Node n) {
wrappedSize[0]++;
}
},
new Predicate() {
@Override
public boolean apply(Node n) {
return wrappedSize[0] < limit;
}
});
return wrappedSize[0];
}
/**
* @return Whether the two node are equivalent while ignoring
* differences any descendant functions differences.
*/
private static boolean isEquivalentToExcludingFunctions(
Node thisNode, Node thatNode) {
if (thisNode == null || thatNode == null) {
return thisNode == null && thatNode == null;
}
if (!thisNode.isEquivalentToShallow(thatNode)) {
return false;
}
if (thisNode.getChildCount() != thatNode.getChildCount()) {
return false;
}
Node thisChild = thisNode.getFirstChild();
Node thatChild = thatNode.getFirstChild();
while (thisChild != null && thatChild != null) {
if (thisChild.isFunction()) {
// don't compare function name, parameters or bodies.
return thatChild.isFunction();
}
if (!isEquivalentToExcludingFunctions(thisChild, thatChild)) {
return false;
}
thisChild = thisChild.getNext();
thatChild = thatChild.getNext();
}
return true;
}
static JSDocInfo createConstantJsDoc() {
JSDocInfoBuilder builder = new JSDocInfoBuilder(false);
builder.recordConstancy();
return builder.build();
}
static int toInt32(double d) {
int id = (int) d;
if (id == d) {
// This covers -0.0 as well
return id;
}
if (Double.isNaN(d)
|| d == Double.POSITIVE_INFINITY
|| d == Double.NEGATIVE_INFINITY) {
return 0;
}
d = (d >= 0) ? Math.floor(d) : Math.ceil(d);
double two32 = 4294967296.0;
d = d % two32;
// (double)(long)d == d should hold here
long l = (long) d;
// returning (int)d does not work as d can be outside int range
// but the result must always be 32 lower bits of l
return (int) l;
}
private static boolean isGoogModuleCall(Node n) {
if (isExprCall(n)) {
Node target = n.getFirstFirstChild();
return (target.matchesQualifiedName("goog.module"));
}
return false;
}
private static boolean isGoogModuleDeclareLegacyNamespaceCall(Node n) {
if (isExprCall(n)) {
Node target = n.getFirstFirstChild();
return (target.matchesQualifiedName("goog.module.declareLegacyNamespace"));
}
return false;
}
/**
* @return Whether the node is a goog.module file's SCRIPT node.
*/
static boolean isGoogModuleFile(Node n) {
return n.isScript() && n.hasChildren() && isGoogModuleCall(n.getFirstChild());
}
/**
* @return Whether the node is a SCRIPT node for a goog.module that has a
* declareLegacyNamespace call.
*/
static boolean isLegacyGoogModuleFile(Node n) {
return isGoogModuleFile(n) && isGoogModuleDeclareLegacyNamespaceCall(n.getSecondChild());
}
}