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Closure Compiler is a JavaScript optimizing compiler. It parses your
JavaScript, analyzes it, removes dead code and rewrites and minimizes
what's left. It also checks syntax, variable references, and types, and
warns about common JavaScript pitfalls. It is used in many of Google's
JavaScript apps, including Gmail, Google Web Search, Google Maps, and
Google Docs.
This binary checks for style issues such as incorrect or missing JSDoc
usage, and missing goog.require() statements. It does not do more advanced
checks such as typechecking.
/*
* Copyright 2011 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 static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Strings.isNullOrEmpty;
import com.google.javascript.jscomp.parsing.parser.FeatureSet;
import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
import com.google.javascript.rhino.InputId;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;
import com.google.javascript.rhino.jstype.FunctionType;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.JSType.Nullability;
import java.util.Objects;
import javax.annotation.Nullable;
/**
* This class walks the AST and validates that the structure is correct.
*
* @author [email protected] (John Lenz)
*/
public final class AstValidator implements CompilerPass {
// Possible enhancements:
// * verify NAME, LABEL_NAME, GETPROP property name and unquoted
// object-literal keys are valid JavaScript identifiers.
// * optionally verify every node has source location information.
/** Violation handler */
public interface ViolationHandler {
void handleViolation(String message, Node n);
}
private final AbstractCompiler compiler;
private final ViolationHandler violationHandler;
private Node currentScript;
/** Perform type validation if this is enabled. */
private boolean isTypeValidationEnabled = false;
/** Validate that a SCRIPT's FeatureSet property includes all features if this is enabled. */
private final boolean isScriptFeatureValidationEnabled;
public AstValidator(
AbstractCompiler compiler, ViolationHandler handler, boolean validateScriptFeatures) {
this.compiler = compiler;
this.violationHandler = handler;
this.isScriptFeatureValidationEnabled = validateScriptFeatures;
}
/**
* Deprecated - use the three-argument constructor instead to specify validateScriptFeatures.
* TODO(lharker): remove this constructor after the next external release.
*/
@Deprecated
public AstValidator(AbstractCompiler compiler, ViolationHandler handler) {
this(compiler, handler, false);
}
public AstValidator(AbstractCompiler compiler) {
this(compiler, /* validateScriptFeatures= */ false);
}
public AstValidator(AbstractCompiler compiler, boolean validateScriptFeatures) {
this(
compiler,
new ViolationHandler() {
@Override
public void handleViolation(String message, Node n) {
throw new IllegalStateException(
message
+ ". Reference node:\n"
+ n.toStringTree()
+ "\n Parent node:\n"
+ ((n.getParent() != null) ? n.getParent().toStringTree() : " no parent "));
}
},
validateScriptFeatures);
}
/**
* Enable or disable validation of type information.
*
* TODO(b/74537281): Currently only expressions are checked for type information.
* Do we need to do more?
*/
public AstValidator setTypeValidationEnabled(boolean isEnabled) {
isTypeValidationEnabled = isEnabled;
return this;
}
@Override
public void process(Node externs, Node root) {
if (externs != null) {
validateCodeRoot(externs);
}
if (root != null) {
validateCodeRoot(root);
}
}
public void validateRoot(Node n) {
validateNodeType(Token.ROOT, n);
validateChildCount(n, 2);
validateCodeRoot(n.getFirstChild());
validateCodeRoot(n.getLastChild());
}
public void validateCodeRoot(Node n) {
validateNodeType(Token.ROOT, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateScript(c);
}
}
public void validateScript(Node n) {
validateNodeType(Token.SCRIPT, n);
validateHasSourceName(n);
validateHasInputId(n);
currentScript = n;
if (n.hasChildren() && n.getFirstChild().isModuleBody()) {
validateChildCount(n, 1);
validateModuleContents(n.getFirstChild());
} else {
validateStatements(n.getFirstChild());
}
}
public void validateModuleContents(Node n) {
validateNodeType(Token.MODULE_BODY, n);
validateStatements(n.getFirstChild());
}
public void validateStatements(Node n) {
while (n != null) {
validateStatement(n);
n = n.getNext();
}
}
public void validateStatement(Node n) {
validateStatement(n, false);
}
public void validateStatement(Node n, boolean isAmbient) {
switch (n.getToken()) {
case LABEL:
validateLabel(n);
return;
case BLOCK:
validateBlock(n);
return;
case FUNCTION:
if (isAmbient) {
validateFunctionSignature(n);
} else {
validateFunctionStatement(n);
}
return;
case WITH:
validateWith(n);
return;
case FOR:
validateFor(n);
return;
case FOR_IN:
validateForIn(n);
return;
case FOR_OF:
validateForOf(n);
return;
case FOR_AWAIT_OF:
validateForAwaitOf(n);
return;
case WHILE:
validateWhile(n);
return;
case DO:
validateDo(n);
return;
case SWITCH:
validateSwitch(n);
return;
case IF:
validateIf(n);
return;
case CONST:
for (Node child : n.children()) {
if (child.isDestructuringLhs()) {
// Must have two children: First child of the DESTRUCTURING_LHS node is the pattern on
// the LHS, second is the RHS.
validateChildCount(child, 2);
} else {
// Must have a child, which is the RHS (unlike VAR and LET which may have no RHS).
validateChildCount(child, 1);
}
}
// fallthrough
case VAR:
case LET:
validateNameDeclarationHelper(n.getToken(), n);
return;
case EXPR_RESULT:
validateExprStmt(n);
return;
case RETURN:
validateReturn(n);
return;
case THROW:
validateThrow(n);
return;
case TRY:
validateTry(n);
return;
case BREAK:
validateBreak(n);
return;
case CONTINUE:
validateContinue(n);
return;
case EMPTY:
case DEBUGGER:
validateChildless(n);
return;
case CLASS:
validateClassDeclaration(n, isAmbient);
return;
case IMPORT:
validateImport(n);
return;
case EXPORT:
validateExport(n, isAmbient);
return;
case INTERFACE:
validateInterface(n);
return;
case ENUM:
validateEnum(n);
return;
case TYPE_ALIAS:
validateTypeAlias(n);
return;
case DECLARE:
validateAmbientDeclaration(n);
return;
case NAMESPACE:
validateNamespace(n, isAmbient);
return;
default:
violation("Expected statement but was " + n.getToken() + ".", n);
}
}
public void validateExpression(Node n) {
if (isTypeValidationEnabled) {
validateExpressionType(n);
}
switch (n.getToken()) {
// Childless expressions
case NEW_TARGET:
validateFeature(Feature.NEW_TARGET, n);
validateChildless(n);
return;
case SUPER:
validateFeature(Feature.SUPER, n);
validateChildless(n);
return;
case FALSE:
case NULL:
case THIS:
case TRUE:
validateChildless(n);
return;
// General unary ops
case DELPROP:
case POS:
case NEG:
case NOT:
case TYPEOF:
case VOID:
case BITNOT:
case CAST:
validateUnaryOp(n);
return;
case INC:
case DEC:
validateIncDecOp(n);
return;
// Assignments
case ASSIGN:
validateAssignmentExpression(n);
return;
case ASSIGN_EXPONENT:
validateFeature(Feature.EXPONENT_OP, n);
validateCompoundAssignmentExpression(n);
return;
case ASSIGN_BITOR:
case ASSIGN_BITXOR:
case ASSIGN_BITAND:
case ASSIGN_LSH:
case ASSIGN_RSH:
case ASSIGN_URSH:
case ASSIGN_ADD:
case ASSIGN_SUB:
case ASSIGN_MUL:
case ASSIGN_DIV:
case ASSIGN_MOD:
validateCompoundAssignmentExpression(n);
return;
case HOOK:
validateTrinaryOp(n);
return;
// Node types that require special handling
case STRING:
validateString(n);
return;
case NUMBER:
validateNumber(n);
return;
case NAME:
validateName(n);
return;
// General binary ops
case EXPONENT:
validateFeature(Feature.EXPONENT_OP, n);
validateBinaryOp(n);
return;
case GETELEM:
case COMMA:
case OR:
case AND:
case BITOR:
case BITXOR:
case BITAND:
case EQ:
case NE:
case SHEQ:
case SHNE:
case LT:
case GT:
case LE:
case GE:
case INSTANCEOF:
case IN:
case LSH:
case RSH:
case URSH:
case SUB:
case ADD:
case MUL:
case MOD:
case DIV:
validateBinaryOp(n);
return;
case GETPROP:
validateGetProp(n);
return;
case ARRAYLIT:
validateArrayLit(n);
return;
case OBJECTLIT:
validateObjectLit(n);
return;
case REGEXP:
validateRegExpLit(n);
return;
case CALL:
validateCall(n);
return;
case NEW:
validateNew(n);
return;
case FUNCTION:
validateFunctionExpression(n);
return;
case CLASS:
validateClass(n);
return;
case TEMPLATELIT:
validateTemplateLit(n);
return;
case TAGGED_TEMPLATELIT:
validateTaggedTemplateLit(n);
return;
case YIELD:
validateYield(n);
return;
case AWAIT:
validateAwait(n);
return;
default:
violation("Expected expression but was " + n.getToken(), n);
}
}
private void validateExpressionType(Node n) {
switch (n.getToken()) {
case NAME:
validateNameType(n);
break;
case CALL:
if (!n.getFirstChild().isSuper()) {
// TODO(sdh): need to validate super() using validateNewType() instead, if it existed
validateCallType(n);
}
break;
default:
expectSomeTypeInformation(n);
}
}
private void validateNameType(Node nameNode) {
// TODO(bradfordcsmith): Looking at ancestors of nameNode is a hack that will prevent validation
// from working on detached nodes.
// Calling code should correctly determine the context and call different methods as
// appropriate.
if (NodeUtil.isExpressionResultUsed(nameNode) && !NodeUtil.isGet(nameNode.getParent())) {
// If the expression result is used, it must have a type.
// However, we don't always add a type when the name is just part of a getProp or getElem.
// That's OK, because we'll do type checking on the getProp/Elm itself, which has a type.
// TODO(b/74537281): Why do we sometimes have type information for names used in getprop
// or getelem expressions and sometimes not?
expectSomeTypeInformation(nameNode);
}
}
private void validateCallType(Node callNode) {
// TODO(b/74537281): Shouldn't CALL nodes always have a type, even if it is unknown?
Node callee = callNode.getFirstChild();
JSType calleeType =
checkNotNull(callee.getJSType(), "Callee of\n\n%s\nhas no type.", callNode.toStringTree());
if (calleeType.isFunctionType()) {
FunctionType calleeFunctionType = calleeType.toMaybeFunctionType();
JSType returnType = calleeFunctionType.getReturnType();
// Skip this check if the call node was originally in a cast, because the cast type may be
// narrower than the return type. Also skip the check if the function's return type is the
// any (formerly unknown) type, since we may have inferred a better type.
if (callNode.getJSTypeBeforeCast() == null && !returnType.isUnknownType()) {
expectMatchingTypeInformation(callNode, returnType);
}
} // TODO(b/74537281): What other cases should be covered?
}
private void expectSomeTypeInformation(Node n) {
if (n.getJSType() == null) {
violation(
"Type information missing" + "\n" + compiler.toSource(NodeUtil.getEnclosingStatement(n)),
n);
}
}
private void expectMatchingTypeInformation(Node n, JSType expectedTypeI) {
JSType typeI = n.getJSType();
if (!Objects.equals(expectedTypeI, typeI)) {
violation(
"Expected type: "
+ getTypeAnnotationString(expectedTypeI)
+ " Actual type: "
+ getTypeAnnotationString(typeI),
n);
}
}
private String getTypeAnnotationString(@Nullable JSType typeI) {
if (typeI == null) {
return "NO TYPE INFORMATION";
} else {
return "{" + typeI.toAnnotationString(Nullability.EXPLICIT) + "}";
}
}
private void validateYield(Node n) {
validateFeature(Feature.GENERATORS, n);
validateNodeType(Token.YIELD, n);
validateChildCountIn(n, 0, 1);
if (n.hasChildren()) {
validateExpression(n.getFirstChild());
}
}
private void validateAwait(Node n) {
validateFeature(Feature.ASYNC_FUNCTIONS, n);
validateNodeType(Token.AWAIT, n);
validateWithinAsyncFunction(n);
}
private void validateWithinAsyncFunction(Node n) {
Node parentFunction = NodeUtil.getEnclosingFunction(n);
if (parentFunction == null || !parentFunction.isAsyncFunction()) {
violation("'await' expression is not within an async function", n);
}
}
private void validateImport(Node n) {
validateFeature(Feature.MODULES, n);
validateNodeType(Token.IMPORT, n);
validateChildCount(n);
if (n.getFirstChild().isName()) {
validateName(n.getFirstChild());
} else {
validateNodeType(Token.EMPTY, n.getFirstChild());
}
Node secondChild = n.getSecondChild();
switch (secondChild.getToken()) {
case IMPORT_SPECS:
validateImportSpecifiers(secondChild);
break;
case IMPORT_STAR:
validateNonEmptyString(secondChild);
break;
default:
validateNodeType(Token.EMPTY, secondChild);
}
validateString(n.getChildAtIndex(2));
}
private void validateImportSpecifiers(Node n) {
validateNodeType(Token.IMPORT_SPECS, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateImportSpecifier(c);
}
}
private void validateImportSpecifier(Node n) {
validateNodeType(Token.IMPORT_SPEC, n);
validateChildCount(n, 2);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateName(c);
}
}
private void validateExport(Node n, boolean isAmbient) {
validateFeature(Feature.MODULES, n);
validateNodeType(Token.EXPORT, n);
if (n.getBooleanProp(Node.EXPORT_ALL_FROM)) { // export * from "mod"
validateChildCount(n, 2);
validateNodeType(Token.EMPTY, n.getFirstChild());
validateString(n.getSecondChild());
} else if (n.getBooleanProp(Node.EXPORT_DEFAULT)) { // export default foo = 2
validateChildCount(n, 1);
validateExpression(n.getFirstChild());
} else {
validateChildCountIn(n, 1, 2);
if (n.getFirstChild().getToken() == Token.EXPORT_SPECS) {
validateExportSpecifiers(n.getFirstChild());
} else {
validateStatement(n.getFirstChild(), isAmbient);
}
if (n.hasTwoChildren()) {
validateString(n.getSecondChild());
}
}
}
private void validateExportSpecifiers(Node n) {
validateNodeType(Token.EXPORT_SPECS, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateExportSpecifier(c);
}
}
private void validateExportSpecifier(Node n) {
validateNodeType(Token.EXPORT_SPEC, n);
validateChildCount(n, 2);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateName(c);
}
}
private void validateTaggedTemplateLit(Node n) {
validateFeature(Feature.TEMPLATE_LITERALS, n);
validateNodeType(Token.TAGGED_TEMPLATELIT, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
validateTemplateLit(n.getLastChild());
}
private void validateTemplateLit(Node n) {
validateFeature(Feature.TEMPLATE_LITERALS, n);
validateNodeType(Token.TEMPLATELIT, n);
for (Node child = n.getFirstChild(); child != null; child = child.getNext()) {
if (child.isTemplateLitString()) {
validateTemplateLitString(child);
} else {
validateTemplateLitSub(child);
}
}
}
private void validateTemplateLitString(Node n) {
validateNodeType(Token.TEMPLATELIT_STRING, n);
validateChildCount(n);
try {
// Validate that getRawString doesn't throw
n.getRawString();
} catch (UnsupportedOperationException e) {
violation("Invalid TEMPLATELIT_STRING node.", n);
}
}
private void validateTemplateLitSub(Node n) {
validateNodeType(Token.TEMPLATELIT_SUB, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
}
private void validateInterface(Node n) {
validateFeature(Feature.INTERFACE, n);
validateNodeType(Token.INTERFACE, n);
validateChildCount(n);
Node name = n.getFirstChild();
validateName(name);
Node superTypes = name.getNext();
if (superTypes.isEmpty()) {
validateChildless(superTypes);
} else {
validateInterfaceExtends(superTypes);
}
validateInterfaceMembers(n.getLastChild());
}
private void validateInterfaceExtends(Node n) {
validateNodeType(Token.INTERFACE_EXTENDS, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateNamedType(c);
}
}
private void validateInterfaceMembers(Node n) {
validateNodeType(Token.INTERFACE_MEMBERS, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateInterfaceMember(c);
}
}
private void validateInterfaceMember(Node n) {
switch (n.getToken()) {
case MEMBER_FUNCTION_DEF:
validateChildCount(n);
validateFunctionSignature(n.getFirstChild());
break;
case MEMBER_VARIABLE_DEF:
validateChildless(n);
break;
case INDEX_SIGNATURE:
validateChildCount(n);
validateChildless(n.getFirstChild());
break;
case CALL_SIGNATURE:
validateChildCount(n);
break;
default:
violation("Interface contained member of invalid type " + n.getToken(), n);
}
}
private void validateEnum(Node n) {
validateNodeType(Token.ENUM, n);
validateName(n.getFirstChild());
validateEnumMembers(n.getLastChild());
}
private void validateEnumMembers(Node n) {
validateNodeType(Token.ENUM_MEMBERS, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateEnumStringKey(c);
}
}
private void validateEnumStringKey(Node n) {
validateNodeType(Token.STRING_KEY, n);
validateObjectLiteralKeyName(n);
validateChildCount(n, 0);
}
/**
* In a class declaration, unlike a class expression,
* the class name is required.
*/
private void validateClassDeclaration(Node n, boolean isAmbient) {
validateClassHelper(n, isAmbient);
validateName(n.getFirstChild());
}
private void validateClass(Node n) {
validateClassHelper(n, false);
}
private void validateClassHelper(Node n, boolean isAmbient) {
validateFeature(Feature.CLASSES, n);
validateNodeType(Token.CLASS, n);
validateChildCount(n);
Node name = n.getFirstChild();
if (name.isEmpty()) {
validateChildless(name);
} else {
validateName(name);
}
Node superClass = name.getNext();
if (superClass.isEmpty()) {
validateChildless(superClass);
} else {
validateFeature(Feature.CLASS_EXTENDS, n);
validateExpression(superClass);
}
validateClassMembers(n.getLastChild(), isAmbient);
}
private void validateClassMembers(Node n, boolean isAmbient) {
validateNodeType(Token.CLASS_MEMBERS, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateClassMember(c, isAmbient);
}
}
private void validateClassMember(Node n, boolean isAmbient) {
switch (n.getToken()) {
case MEMBER_FUNCTION_DEF:
validateFeature(Feature.MEMBER_DECLARATIONS, n);
validateObjectLiteralKeyName(n);
validateChildCount(n);
validateMemberFunction(n, isAmbient);
break;
case GETTER_DEF:
case SETTER_DEF:
validateFeature(Feature.CLASS_GETTER_SETTER, n);
validateObjectLiteralKeyName(n);
validateChildCount(n);
validateMemberFunction(n, isAmbient);
break;
case MEMBER_VARIABLE_DEF:
validateChildless(n);
break;
case COMPUTED_PROP:
validateComputedPropClassMethod(n);
break;
case INDEX_SIGNATURE:
validateChildCount(n);
validateChildless(n.getFirstChild());
break;
case CALL_SIGNATURE:
validateChildCount(n);
break;
case EMPTY: // Empty is allowed too.
break;
default:
violation("Class contained member of invalid type " + n.getToken(), n);
}
}
private void validateMemberFunction(Node n, boolean isAmbient) {
Node function = n.getFirstChild();
if (isAmbient) {
validateFunctionSignature(function);
} else {
validateFunctionExpression(function);
}
}
private void validateBlock(Node n) {
validateNodeType(Token.BLOCK, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateStatement(c);
}
}
private void validateHasSourceName(Node n) {
String sourceName = n.getSourceFileName();
if (isNullOrEmpty(sourceName)) {
violation("Missing 'source name' annotation.", n);
}
}
private void validateHasInputId(Node n) {
InputId inputId = n.getInputId();
if (inputId == null) {
violation("Missing 'input id' annotation.", n);
}
}
private void validateLabel(Node n) {
validateNodeType(Token.LABEL, n);
validateChildCount(n);
validateLabelName(n.getFirstChild());
validateStatement(n.getLastChild());
}
private void validateLabelName(Node n) {
validateNodeType(Token.LABEL_NAME, n);
validateNonEmptyString(n);
validateChildCount(n);
}
private void validateNonEmptyString(Node n) {
if (validateNonNullString(n) && n.getString().isEmpty()) {
violation("Expected non-empty string.", n);
}
}
private void validateEmptyString(Node n) {
if (validateNonNullString(n) && !n.getString().isEmpty()) {
violation("Expected empty string.", n);
}
}
private boolean validateNonNullString(Node n) {
try {
if (n.getString() == null) {
violation("Expected non-null string.", n);
return false;
}
} catch (Exception e) {
violation("Expected non-null string.", n);
return false;
}
return true;
}
private void validateName(Node n) {
validateNodeType(Token.NAME, n);
validateNonEmptyString(n);
validateChildCount(n);
}
private void validateOptionalName(Node n) {
validateNodeType(Token.NAME, n);
validateNonNullString(n);
validateChildCount(n);
}
private void validateEmptyName(Node n) {
validateNodeType(Token.NAME, n);
validateEmptyString(n);
validateChildCount(n);
}
private void validateFunctionStatement(Node n) {
validateNodeType(Token.FUNCTION, n);
validateChildCount(n);
validateName(n.getFirstChild());
validateParameters(n.getSecondChild());
validateFunctionBody(n.getLastChild(), false);
validateFunctionFeatures(n);
if (n.getParent().isBlock() && !n.getGrandparent().isFunction()) {
// e.g. if (true) { function f() {} }
validateFeature(Feature.BLOCK_SCOPED_FUNCTION_DECLARATION, n);
}
}
private void validateFunctionExpression(Node n) {
validateFunctionExpressionHelper(n, false);
}
private void validateFunctionSignature(Node n) {
validateFunctionExpressionHelper(n, true);
}
private void validateFunctionExpressionHelper(Node n, boolean isAmbient) {
validateNodeType(Token.FUNCTION, n);
validateChildCount(n);
validateParameters(n.getSecondChild());
Node name = n.getFirstChild();
Node body = n.getLastChild();
if (n.isArrowFunction()) {
validateEmptyName(name);
if (body.isBlock()) {
validateBlock(body);
} else {
validateExpression(body);
}
} else {
validateOptionalName(name);
validateFunctionBody(body, isAmbient);
}
validateFunctionFeatures(n);
}
private void validateFunctionFeatures(Node n) {
if (n.isArrowFunction()) {
validateFeature(Feature.ARROW_FUNCTIONS, n);
}
if (n.isGeneratorFunction()) {
validateFeature(Feature.GENERATORS, n);
}
if (n.isAsyncFunction()) {
validateFeature(Feature.ASYNC_FUNCTIONS, n);
}
if (n.isAsyncFunction() && n.isGeneratorFunction()) {
validateFeature(Feature.ASYNC_GENERATORS, n);
}
}
private void validateFunctionBody(Node n, boolean noBlock) {
if (noBlock) {
validateNodeType(Token.EMPTY, n);
} else {
validateBlock(n);
}
}
private void validateParameters(Node n) {
validateNodeType(Token.PARAM_LIST, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (c.isRest()) {
validateRestParameters(Token.PARAM_LIST, c);
} else if (c.isDefaultValue()) {
validateFeature(Feature.DEFAULT_PARAMETERS, c);
validateDefaultValue(Token.PARAM_LIST, c);
} else {
if (c.isName()) {
validateName(c);
} else if (c.isArrayPattern()) {
validateArrayPattern(Token.PARAM_LIST, c);
} else {
validateObjectPattern(Token.PARAM_LIST, c);
}
}
}
}
private void validateDefaultValue(Token contextType, Node n) {
validateChildCount(n);
validateLHS(contextType, n.getFirstChild());
validateExpression(n.getLastChild());
}
private void validateCall(Node n) {
validateNodeType(Token.CALL, n);
validateMinimumChildCount(n, 1);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
switch (c.getToken()) {
case SPREAD:
validateSpread(c);
break;
default:
validateExpression(c);
break;
}
}
}
private void validateRestParameters(Token contextType, Node n) {
validateFeature(Feature.REST_PARAMETERS, n);
validateRest(contextType, n);
}
private void validateArrayPatternRest(Token contextType, Node n) {
validateFeature(Feature.ARRAY_PATTERN_REST, n);
validateRest(contextType, n);
}
private void validateObjectPatternRest(Token contextType, Node n) {
validateFeature(Feature.OBJECT_PATTERN_REST, n);
validateRest(contextType, n);
}
/**
* @param contextType A {@link Token} constant value indicating that {@code n} should be validated
* appropriately for a descendant of a {@link Node} of this type.
* @param n
*/
private void validateRest(Token contextType, Node n) {
validateNodeType(Token.REST, n);
validateChildCount(n);
validateLHS(contextType, n.getFirstChild());
if (n.getNext() != null) {
violation("Rest parameters must come after all other parameters.", n);
}
}
private void validateSpread(Node n) {
validateNodeType(Token.SPREAD, n);
validateChildCount(n);
Node parent = n.getParent();
switch (parent.getToken()) {
case CALL:
case NEW:
if (n == parent.getFirstChild()) {
violation("SPREAD node is not callable.", n);
}
validateFeature(Feature.SPREAD_EXPRESSIONS, n);
break;
case OBJECTLIT:
validateFeature(Feature.OBJECT_LITERALS_WITH_SPREAD, n);
validateFeature(Feature.SPREAD_EXPRESSIONS, n);
break;
case ARRAYLIT:
validateFeature(Feature.SPREAD_EXPRESSIONS, n);
break;
default:
violation("SPREAD node should not be the child of a " + parent.getToken() + " node.", n);
}
}
private void validateNew(Node n) {
validateNodeType(Token.NEW, n);
validateMinimumChildCount(n, 1);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
switch (c.getToken()) {
case SPREAD:
validateSpread(c);
break;
default:
validateExpression(c);
break;
}
}
}
private void validateNameDeclarationHelper(Token type, Node n) {
validateMinimumChildCount(n, 1);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateNameDeclarationChild(type, c);
}
if (type == Token.LET) {
validateFeature(Feature.LET_DECLARATIONS, n);
} else if (type == Token.CONST) {
validateFeature(Feature.CONST_DECLARATIONS, n);
}
}
private void validateNameDeclarationChild(Token type, Node n) {
if (n.isName()) {
// Don't use validateName here since this NAME node may have
// a child.
validateNonEmptyString(n);
validateMaximumChildCount(n, 1);
if (n.hasChildren()) {
validateExpression(n.getFirstChild());
}
} else if (n.isDestructuringLhs()) {
validateDestructuringLhs(type, n);
} else {
violation("Invalid child for " + type + " node", n);
}
}
private void validateDestructuringLhs(Token type, Node n) {
validateChildCountIn(n, 1, 2);
Node c = n.getFirstChild();
switch (c.getToken()) {
case ARRAY_PATTERN:
validateArrayPattern(type, c);
break;
case OBJECT_PATTERN:
validateObjectPattern(type, c);
break;
default:
violation("Invalid destructuring lhs first child for " + type + " node", n);
}
if (n.hasTwoChildren()) {
validateExpression(n.getSecondChild());
}
}
/**
* @param contextType A {@link Token} constant value indicating that {@code n} should be validated
* appropriately for a descendant of a {@link Node} of this type.
* @param n
*/
private void validateLHS(Token contextType, Node n) {
switch (n.getToken()) {
case NAME:
validateName(n);
break;
case ARRAY_PATTERN:
validateArrayPattern(contextType, n);
break;
case OBJECT_PATTERN:
validateObjectPattern(contextType, n);
break;
case GETPROP:
case GETELEM:
validateGetPropGetElemInLHS(contextType, n);
break;
case CAST:
validateLHS(contextType, n.getOnlyChild());
break;
default:
violation("Invalid child for " + contextType + " node", n);
}
}
private void validateGetPropGetElemInLHS(Token contextType, Node n) {
if (contextType == Token.CONST || contextType == Token.LET || contextType == Token.VAR
|| contextType == Token.PARAM_LIST) {
violation("Invalid child for " + contextType + " node", n);
return;
}
switch (n.getToken()) {
case GETPROP:
validateGetProp(n);
break;
case GETELEM:
validateBinaryOp(n);
break;
default:
throw new IllegalStateException(
"Expected GETPROP or GETELEM but instead got node " + n.getToken());
}
}
private void validateArrayPattern(Token type, Node n) {
validateFeature(Feature.ARRAY_DESTRUCTURING, n);
validateNodeType(Token.ARRAY_PATTERN, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
switch (c.getToken()) {
case DEFAULT_VALUE:
validateDefaultValue(type, c);
break;
case REST:
validateArrayPatternRest(type, c);
break;
case EMPTY:
validateChildless(c);
break;
default:
validateLHS(type, c);
}
}
}
private void validateObjectPattern(Token type, Node n) {
validateFeature(Feature.OBJECT_DESTRUCTURING, n);
validateNodeType(Token.OBJECT_PATTERN, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
switch (c.getToken()) {
case STRING_KEY:
validateObjectPatternStringKey(type, c);
break;
case REST:
validateObjectPatternRest(type, c);
break;
case COMPUTED_PROP:
validateObjectPatternComputedPropKey(type, c);
break;
default:
violation("Invalid object pattern child for " + type + " node", n);
}
}
}
private void validateFor(Node n) {
validateNodeType(Token.FOR, n);
validateChildCount(n, 4);
validateVarOrOptionalExpression(n.getFirstChild());
validateOptionalExpression(n.getSecondChild());
validateOptionalExpression(n.getChildAtIndex(2));
validateBlock(n.getLastChild());
}
private void validateForIn(Node n) {
validateNodeType(Token.FOR_IN, n);
validateChildCount(n);
validateVarOrAssignmentTarget(n.getFirstChild());
validateExpression(n.getSecondChild());
validateBlock(n.getLastChild());
}
private void validateForOf(Node n) {
validateFeature(Feature.FOR_OF, n);
validateNodeType(Token.FOR_OF, n);
validateChildCount(n);
validateVarOrAssignmentTarget(n.getFirstChild());
validateExpression(n.getSecondChild());
validateBlock(n.getLastChild());
}
private void validateForAwaitOf(Node n) {
validateFeature(Feature.FOR_AWAIT_OF, n);
validateNodeType(Token.FOR_AWAIT_OF, n);
validateChildCount(n);
validateVarOrAssignmentTarget(n.getFirstChild());
validateExpression(n.getSecondChild());
validateBlock(n.getLastChild());
}
private void validateVarOrOptionalExpression(Node n) {
if (NodeUtil.isNameDeclaration(n)) {
validateNameDeclarationHelper(n.getToken(), n);
} else {
validateOptionalExpression(n);
}
}
private void validateVarOrAssignmentTarget(Node n) {
if (NodeUtil.isNameDeclaration(n)) {
// Only one NAME can be declared for FOR-IN expressions.
validateChildCount(n, 1);
validateNameDeclarationHelper(n.getToken(), n);
} else {
validateLHS(n.getParent().getToken(), n);
}
}
private void validateWith(Node n) {
validateNodeType(Token.WITH, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
validateBlock(n.getLastChild());
}
private void validateWhile(Node n) {
validateNodeType(Token.WHILE, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
validateBlock(n.getLastChild());
}
private void validateDo(Node n) {
validateNodeType(Token.DO, n);
validateChildCount(n);
validateBlock(n.getFirstChild());
validateExpression(n.getLastChild());
}
private void validateIf(Node n) {
validateNodeType(Token.IF, n);
validateChildCountIn(n, 2, 3);
validateExpression(n.getFirstChild());
validateBlock(n.getSecondChild());
if (n.hasXChildren(3)) {
validateBlock(n.getLastChild());
}
}
private void validateExprStmt(Node n) {
validateNodeType(Token.EXPR_RESULT, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
}
private void validateReturn(Node n) {
validateNodeType(Token.RETURN, n);
validateMaximumChildCount(n, 1);
if (n.hasChildren()) {
validateExpression(n.getFirstChild());
}
}
private void validateThrow(Node n) {
validateNodeType(Token.THROW, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
}
private void validateBreak(Node n) {
validateNodeType(Token.BREAK, n);
validateMaximumChildCount(n, 1);
if (n.hasChildren()) {
validateLabelName(n.getFirstChild());
}
}
private void validateContinue(Node n) {
validateNodeType(Token.CONTINUE, n);
validateMaximumChildCount(n, 1);
if (n.hasChildren()) {
validateLabelName(n.getFirstChild());
}
}
private void validateTry(Node n) {
validateNodeType(Token.TRY, n);
validateChildCountIn(n, 2, 3);
validateBlock(n.getFirstChild());
boolean seenCatchOrFinally = false;
// Validate catch
Node catches = n.getSecondChild();
validateNodeType(Token.BLOCK, catches);
validateMaximumChildCount(catches, 1);
if (catches.hasChildren()) {
validateCatch(catches.getFirstChild());
seenCatchOrFinally = true;
}
// Validate finally
if (n.hasXChildren(3)) {
validateBlock(n.getLastChild());
seenCatchOrFinally = true;
}
if (!seenCatchOrFinally) {
violation("Missing catch or finally for try statement.", n);
}
}
private void validateCatch(Node n) {
validateNodeType(Token.CATCH, n);
validateChildCount(n);
Node caught = n.getFirstChild();
if (caught.isName()) {
validateName(caught);
} else if (caught.isArrayPattern()) {
validateArrayPattern(Token.CATCH, caught);
} else if (caught.isObjectPattern()) {
validateObjectPattern(Token.CATCH, caught);
} else if (caught.isEmpty()) {
validateNoCatchBinding(caught);
} else {
violation("Unexpected catch binding: " + caught, n);
}
validateBlock(n.getLastChild());
}
private void validateNoCatchBinding(Node n) {
validateFeature(Feature.OPTIONAL_CATCH_BINDING, n);
validateChildCount(n);
}
private void validateSwitch(Node n) {
validateNodeType(Token.SWITCH, n);
validateMinimumChildCount(n, 1);
validateExpression(n.getFirstChild());
int defaults = 0;
for (Node c = n.getSecondChild(); c != null; c = c.getNext()) {
validateSwitchMember(n.getLastChild());
if (c.isDefaultCase()) {
defaults++;
}
}
if (defaults > 1) {
violation("Expected at most 1 'default' in switch but was "
+ defaults, n);
}
}
private void validateSwitchMember(Node n) {
switch (n.getToken()) {
case CASE:
validateCase(n);
return;
case DEFAULT_CASE:
validateDefaultCase(n);
return;
default:
violation("Expected switch member but was " + n.getToken(), n);
}
}
private void validateDefaultCase(Node n) {
validateNodeType(Token.DEFAULT_CASE, n);
validateChildCount(n);
validateBlock(n.getLastChild());
}
private void validateCase(Node n) {
validateNodeType(Token.CASE, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
validateBlock(n.getLastChild());
}
private void validateOptionalExpression(Node n) {
if (n.isEmpty()) {
validateChildless(n);
} else {
validateExpression(n);
}
}
private void validateChildless(Node n) {
validateChildCount(n, 0);
}
private void validateAssignmentExpression(Node n) {
validateChildCount(n);
validateLHS(n.getToken(), n.getFirstChild());
validateExpression(n.getLastChild());
}
private void validateCompoundAssignmentExpression(Node n) {
validateChildCount(n);
Token contextType = n.getToken();
Node lhs = n.getFirstChild();
switch (lhs.getToken()) {
case NAME:
validateName(lhs);
break;
case GETPROP:
case GETELEM:
validateGetPropGetElemInLHS(contextType, lhs);
break;
default:
violation("Invalid child for " + contextType + " node", lhs);
}
validateExpression(n.getLastChild());
}
private void validateGetProp(Node n) {
validateNodeType(Token.GETPROP, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
Node prop = n.getLastChild();
validateNodeType(Token.STRING, prop);
validateNonEmptyString(prop);
}
private void validateRegExpLit(Node n) {
validateNodeType(Token.REGEXP, n);
validateChildCountIn(n, 1, 2);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateString(c);
}
}
private void validateString(Node n) {
validateNodeType(Token.STRING, n);
validateChildCount(n);
try {
// Validate that getString doesn't throw
n.getString();
} catch (UnsupportedOperationException e) {
violation("Invalid STRING node.", n);
}
}
private void validateNumber(Node n) {
validateNodeType(Token.NUMBER, n);
validateChildCount(n);
try {
// Validate that getDouble doesn't throw
n.getDouble();
} catch (UnsupportedOperationException e) {
violation("Invalid NUMBER node.", n);
}
}
private void validateArrayLit(Node n) {
validateNodeType(Token.ARRAYLIT, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
switch (c.getToken()) {
case SPREAD:
validateSpread(c);
break;
default:
// Optional because array-literals may have empty slots.
validateOptionalExpression(c);
break;
}
}
}
private void validateObjectLit(Node n) {
validateNodeType(Token.OBJECTLIT, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
validateObjectLitKey(c);
}
}
private void validateObjectLitKey(Node n) {
switch (n.getToken()) {
case GETTER_DEF:
validateObjectLitGetKey(n);
return;
case SETTER_DEF:
validateObjectLitSetKey(n);
return;
case STRING_KEY:
validateObjectLitStringKey(n);
return;
case MEMBER_FUNCTION_DEF:
validateClassMember(n, false);
if (n.isStaticMember()) {
violation("Keys in an object literal should not be static.", n);
}
return;
case COMPUTED_PROP:
validateObjectLitComputedPropKey(n);
return;
case SPREAD:
validateSpread(n);
return;
default:
violation("Expected object literal key expression but was " + n.getToken(), n);
}
}
private void validateObjectLitGetKey(Node n) {
validateFeature(Feature.GETTER, n);
validateNodeType(Token.GETTER_DEF, n);
validateChildCount(n);
validateObjectLiteralKeyName(n);
Node function = n.getFirstChild();
validateFunctionExpression(function);
// objlit get functions must be nameless, and must have zero parameters.
if (!function.getFirstChild().getString().isEmpty()) {
violation("Expected unnamed function expression.", n);
}
Node functionParams = function.getSecondChild();
if (functionParams.hasChildren()) {
violation("get methods must not have parameters.", n);
}
}
private void validateObjectLitSetKey(Node n) {
validateFeature(Feature.SETTER, n);
validateNodeType(Token.SETTER_DEF, n);
validateChildCount(n);
validateObjectLiteralKeyName(n);
Node function = n.getFirstChild();
validateFunctionExpression(function);
// objlit set functions must be nameless, and must have 1 parameter.
if (!function.getFirstChild().getString().isEmpty()) {
violation("Expected unnamed function expression.", n);
}
Node functionParams = function.getSecondChild();
if (!functionParams.hasOneChild()) {
violation("set methods must have exactly one parameter.", n);
}
}
private void validateObjectLitStringKey(Node n) {
validateNodeType(Token.STRING_KEY, n);
validateObjectLiteralKeyName(n);
validateChildCount(n, 1);
validateExpression(n.getFirstChild());
if (n.getBooleanProp(Node.IS_SHORTHAND_PROPERTY)) {
validateFeature(Feature.EXTENDED_OBJECT_LITERALS, n);
}
}
private void validateObjectPatternStringKey(Token type, Node n) {
validateNodeType(Token.STRING_KEY, n);
validateObjectLiteralKeyName(n);
validateChildCount(n, 1);
Node c = n.getFirstChild();
switch (c.getToken()) {
case DEFAULT_VALUE:
validateDefaultValue(type, c);
break;
default:
validateLHS(type, c);
}
}
private void validateObjectLitComputedPropKey(Node n) {
validateFeature(Feature.COMPUTED_PROPERTIES, n);
validateNodeType(Token.COMPUTED_PROP, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
validateExpression(n.getLastChild());
}
private void validateObjectPatternComputedPropKey(Token type, Node n) {
validateFeature(Feature.COMPUTED_PROPERTIES, n);
validateNodeType(Token.COMPUTED_PROP, n);
validateChildCount(n);
validateExpression(n.getFirstChild());
if (n.getLastChild().isDefaultValue()) {
validateDefaultValue(type, n.getLastChild());
} else {
validateLHS(n.getLastChild().getToken(), n.getLastChild());
}
}
private void validateComputedPropClassMethod(Node n) {
validateFeature(Feature.COMPUTED_PROPERTIES, n);
validateNodeType(Token.COMPUTED_PROP, n);
validateExpression(n.getFirstChild());
if (n.getBooleanProp(Node.COMPUTED_PROP_VARIABLE)) {
validateChildCount(n, 1);
} else {
validateChildCount(n, 2);
validateFunctionExpression(n.getLastChild());
}
}
private void validateObjectLiteralKeyName(Node n) {
if (n.isQuotedString()) {
try {
// Validate that getString doesn't throw
n.getString();
} catch (UnsupportedOperationException e) {
violation("getString failed for" + n.getToken(), n);
}
} else {
validateNonEmptyString(n);
}
}
private void validateIncDecOp(Node n) {
validateChildCount(n, 1);
validateIncDecTarget(n.getFirstChild());
}
private void validateIncDecTarget(Node n) {
switch (n.getToken()) {
case NAME:
case GETPROP:
case GETELEM:
validateExpression(n);
break;
case CAST:
validateChildCount(n.getFirstChild(), 1);
validateIncDecTarget(n.getFirstChild());
break;
default:
violation("Invalid INC/DEC target " + n.getToken(), n);
}
}
private void validateUnaryOp(Node n) {
validateChildCount(n, 1);
validateExpression(n.getFirstChild());
}
private void validateBinaryOp(Node n) {
validateChildCount(n, 2);
validateExpression(n.getFirstChild());
validateExpression(n.getLastChild());
}
private void validateTrinaryOp(Node n) {
validateChildCount(n, 3);
Node first = n.getFirstChild();
validateExpression(first);
validateExpression(first.getNext());
validateExpression(n.getLastChild());
}
private void validateNamedType(Node n) {
validateNodeType(Token.NAMED_TYPE, n);
validateChildCount(n);
validateName(n.getFirstChild());
}
private void validateTypeAlias(Node n) {
validateFeature(Feature.TYPE_ALIAS, n);
validateNodeType(Token.TYPE_ALIAS, n);
validateChildCount(n);
}
private void validateAmbientDeclaration(Node n) {
validateFeature(Feature.AMBIENT_DECLARATION, n);
validateNodeType(Token.DECLARE, n);
validateAmbientDeclarationHelper(n.getFirstChild());
}
private void validateAmbientDeclarationHelper(Node n) {
switch (n.getToken()) {
case VAR:
case LET:
case CONST:
validateNameDeclarationHelper(n.getToken(), n);
break;
case FUNCTION:
validateFunctionSignature(n);
break;
case CLASS:
validateClassDeclaration(n, true);
break;
case ENUM:
validateEnum(n);
break;
case NAMESPACE:
validateNamespace(n, true);
break;
case TYPE_ALIAS:
validateTypeAlias(n);
break;
case EXPORT:
validateExport(n, true);
break;
default:
break;
}
}
private void validateNamespace(Node n, boolean isAmbient) {
validateFeature(Feature.NAMESPACE_DECLARATION, n);
validateNodeType(Token.NAMESPACE, n);
validateChildCount(n);
validateNamespaceName(n.getFirstChild());
validateNamespaceElements(n.getLastChild(), isAmbient);
}
private void validateNamespaceName(Node n) {
switch (n.getToken()) {
case NAME:
validateName(n);
break;
case GETPROP:
validateGetProp(n);
break;
default:
break;
}
}
private void validateNamespaceElements(Node n, boolean isAmbient) {
validateNodeType(Token.NAMESPACE_ELEMENTS, n);
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (isAmbient) {
validateAmbientDeclarationHelper(c);
} else {
validateStatement(c);
}
}
}
private void violation(String message, Node n) {
violationHandler.handleViolation(message, n);
}
private void validateNodeType(Token type, Node n) {
if (n.getToken() != type) {
violation("Expected " + type + " but was " + n.getToken(), n);
}
}
private void validateChildCount(Node n) {
int expectedArity = Token.arity(n.getToken());
if (expectedArity != -1) {
validateChildCount(n, expectedArity);
}
}
private void validateChildCount(Node n, int expected) {
int count = n.getChildCount();
if (expected != count) {
violation("Expected " + expected + " children, but was " + count, n);
}
}
private void validateChildCountIn(Node n, int min, int max) {
int count = n.getChildCount();
if (count < min || count > max) {
violation("Expected child count in [" + min + ", " + max
+ "], but was " + count, n);
}
}
private void validateMinimumChildCount(Node n, int i) {
boolean valid = false;
if (i == 1) {
valid = n.hasChildren();
} else if (i == 2) {
valid = n.hasMoreThanOneChild();
} else {
valid = n.getChildCount() >= i;
}
if (!valid) {
violation("Expected at least " + i + " children, but was " + n.getChildCount(), n);
}
}
private void validateMaximumChildCount(Node n, int i) {
boolean valid = false;
if (i == 1) {
valid = !n.hasMoreThanOneChild();
} else if (i == -1) {
valid = true; // Varying number of children.
} else {
valid = n.getChildCount() <= i;
}
if (!valid) {
violation("Expected no more than " + i + " children, but was " + n.getChildCount(), n);
}
}
private void validateFeature(Feature feature, Node n) {
if (!n.isFromExterns() && !compiler.getFeatureSet().has(feature)) {
// Skip this check for externs because we don't need to complete transpilation on externs,
// and currently only transpile externs so that we can typecheck ES6+ features in externs.
violation("AST should not contain " + feature, n);
}
// Note: currentScript may be null if someone called validateStatement or validateExpression
if (!isScriptFeatureValidationEnabled || currentScript == null) {
return;
}
FeatureSet scriptFeatures = NodeUtil.getFeatureSetOfScript(currentScript);
if (scriptFeatures == null || !NodeUtil.getFeatureSetOfScript(currentScript).has(feature)) {
violation("SCRIPT node should be marked as containing feature " + feature, currentScript);
}
}
}