com.google.javascript.jscomp.AstFactory Maven / Gradle / Ivy
/*
* Copyright 2018 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.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.jstype.BooleanLiteralSet;
import com.google.javascript.rhino.jstype.FunctionType;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.JSTypeNative;
import com.google.javascript.rhino.jstype.JSTypeRegistry;
import com.google.javascript.rhino.jstype.ObjectType;
import javax.annotation.Nullable;
/**
* Creates AST nodes and subtrees.
*
* This class supports creating nodes either with or without type information.
*
*
The idea is that client code can create the trees of nodes it needs without having to contain
* logic for deciding whether type information should be added or not, and only minimal logic for
* determining which types to add when they are necessary. Most methods in this class are able to
* determine the correct type information from already existing AST nodes and the current scope.
*/
final class AstFactory {
@Nullable private final JSTypeRegistry registry;
private AstFactory() {
this.registry = null;
}
private AstFactory(JSTypeRegistry registry) {
this.registry = registry;
}
static AstFactory createFactoryWithoutTypes() {
return new AstFactory();
}
static AstFactory createFactoryWithTypes(JSTypeRegistry registry) {
return new AstFactory(registry);
}
/** Does this class instance add types to the nodes it creates? */
boolean isAddingTypes() {
return registry != null;
}
Node createString(String value) {
Node result = IR.string(value);
if (isAddingTypes()) {
result.setJSType(getNativeType(JSTypeNative.STRING_TYPE));
}
return result;
}
Node createNumber(double value) {
Node result = IR.number(value);
if (isAddingTypes()) {
result.setJSType(getNativeType(JSTypeNative.NUMBER_TYPE));
}
return result;
}
Node createBoolean(boolean value) {
Node result = value ? IR.trueNode() : IR.falseNode();
if (isAddingTypes()) {
result.setJSType(getNativeType(JSTypeNative.BOOLEAN_TYPE));
}
return result;
}
Node createNull() {
Node result = IR.nullNode();
if (isAddingTypes()) {
result.setJSType(getNativeType(JSTypeNative.NULL_TYPE));
}
return result;
}
Node createThis(JSType thisType) {
Node result = IR.thisNode();
if (isAddingTypes()) {
result.setJSType(checkNotNull(thisType));
}
return result;
}
/**
* Creates a reference to "arguments" with the type specified in externs, or unknown if the
* externs for it weren't included.
*/
Node createArgumentsReference() {
Node result = IR.name("arguments");
if (isAddingTypes()) {
JSType argumentsType = registry.getGlobalType("Arguments");
if (argumentsType == null) {
argumentsType = getNativeType(JSTypeNative.UNKNOWN_TYPE);
}
result.setJSType(argumentsType);
}
return result;
}
Node createName(String name, JSType type) {
Node result = IR.name(name);
if (isAddingTypes()) {
result.setJSType(checkNotNull(type));
}
return result;
}
Node createName(String name, JSTypeNative nativeType) {
Node result = IR.name(name);
if (isAddingTypes()) {
result.setJSType(getNativeType(nativeType));
}
return result;
}
Node createName(Scope scope, String name) {
Node result = IR.name(name);
if (isAddingTypes()) {
result.setJSType(getVarNameType(scope, name));
}
return result;
}
Node createQName(Scope scope, String qname) {
return createQName(scope, Splitter.on(".").split(qname));
}
private Node createQName(Scope scope, Iterable names) {
String baseName = checkNotNull(Iterables.getFirst(names, null));
Iterable propertyNames = Iterables.skip(names, 1);
Node baseNameNode = createName(scope, baseName);
return createGetProps(baseNameNode, propertyNames);
}
Node createGetProp(Node receiver, String propertyName) {
Node result = IR.getprop(receiver, IR.string(propertyName));
if (isAddingTypes()) {
result.setJSType(getJsTypeForProperty(receiver, propertyName));
}
return result;
}
/** Creates a tree of nodes representing `receiver.name1.name2.etc`. */
private Node createGetProps(Node receiver, Iterable propertyNames) {
Node result = receiver;
for (String propertyName : propertyNames) {
result = createGetProp(result, propertyName);
}
return result;
}
Node createGetElem(Node receiver, Node key) {
Node result = IR.getelem(receiver, key);
if (isAddingTypes()) {
// In general we cannot assume we know the type we get from a GETELEM.
// TODO(bradfordcsmith): When receiver is an Array or an Object, use the template
// type here.
result.setJSType(getNativeType(JSTypeNative.UNKNOWN_TYPE));
}
return result;
}
Node createStringKey(String key, Node value) {
Node result = IR.stringKey(key, value);
if (isAddingTypes()) {
result.setJSType(value.getJSType());
}
return result;
}
Node createComputedProperty(Node key, Node value) {
Node result = IR.computedProp(key, value);
if (isAddingTypes()) {
result.setJSType(value.getJSType());
}
return result;
}
Node createIn(Node left, Node right) {
Node result = IR.in(left, right);
if (isAddingTypes()) {
result.setJSType(getNativeType(JSTypeNative.BOOLEAN_TYPE));
}
return result;
}
Node createComma(Node left, Node right) {
Node result = IR.comma(left, right);
if (isAddingTypes()) {
result.setJSType(right.getJSType());
}
return result;
}
Node createCommas(Node first, Node second, Node... rest) {
Node result = createComma(first, second);
for (Node next : rest) {
result = createComma(result, next);
}
return result;
}
Node createAnd(Node left, Node right) {
Node result = IR.and(left, right);
if (isAddingTypes()) {
JSType leftType = checkNotNull(left.getJSType(), left);
JSType rightType = checkNotNull(right.getJSType(), right);
BooleanLiteralSet possibleLhsBooleanValues = leftType.getPossibleToBooleanOutcomes();
switch (possibleLhsBooleanValues) {
case TRUE:
// left cannot be false, so rhs will always be evaluated
result.setJSType(rightType);
break;
case FALSE:
// left cannot be true, so rhs will never be evaluated
result.setJSType(leftType);
break;
case BOTH:
// result could be the type of either the lhs or the rhs
result.setJSType(leftType.getLeastSupertype(rightType));
break;
default:
checkState(
possibleLhsBooleanValues == BooleanLiteralSet.EMPTY,
"unexpected enum value: %s",
possibleLhsBooleanValues);
// TODO(bradfordcsmith): Should we be trying to determine whether we actually need
// NO_OBJECT_TYPE or similar here? It probably doesn't matter since this code is
// expected to execute only after all static type analysis has been done.
result.setJSType(getNativeType(JSTypeNative.NO_TYPE));
break;
}
}
return result;
}
Node createOr(Node left, Node right) {
Node result = IR.or(left, right);
if (isAddingTypes()) {
JSType leftType = checkNotNull(left.getJSType(), left);
JSType rightType = checkNotNull(right.getJSType(), right);
BooleanLiteralSet possibleLhsBooleanValues = leftType.getPossibleToBooleanOutcomes();
switch (possibleLhsBooleanValues) {
case TRUE:
// left cannot be false, so rhs will never be evaluated
result.setJSType(leftType);
break;
case FALSE:
// left cannot be true, so rhs will always be evaluated
result.setJSType(rightType);
break;
case BOTH:
// result could be the type of either the lhs or the rhs
result.setJSType(leftType.getLeastSupertype(rightType));
break;
default:
checkState(
possibleLhsBooleanValues == BooleanLiteralSet.EMPTY,
"unexpected enum value: %s",
possibleLhsBooleanValues);
// TODO(bradfordcsmith): Should we be trying to determine whether we actually need
// NO_OBJECT_TYPE or similar here? It probably doesn't matter since this code is
// expected to execute only after all static type analysis has been done.
result.setJSType(getNativeType(JSTypeNative.NO_TYPE));
break;
}
}
return result;
}
Node createCall(Node callee, Node... args) {
Node result = NodeUtil.newCallNode(callee, args);
if (isAddingTypes()) {
FunctionType calleeType = JSType.toMaybeFunctionType(callee.getJSType());
// TODO(sdh): this does not handle generic functions - we'd need to unify the argument types.
// checkState(calleeType == null || !calleeType.hasAnyTemplateTypes(), calleeType);
// TODO(bradfordcsmith): Consider throwing an exception if calleeType is null.
JSType returnType =
calleeType != null
? calleeType.getReturnType()
: getNativeType(JSTypeNative.UNKNOWN_TYPE);
result.setJSType(returnType);
}
return result;
}
/**
* Create a call that returns an instance of the given class type.
*
* This method is intended for use in special cases, such as calling `super()` in a
* constructor.
*/
Node createConstructorCall(@Nullable JSType classType, Node callee, Node... args) {
Node result = NodeUtil.newCallNode(callee, args);
if (isAddingTypes()) {
checkNotNull(classType);
FunctionType constructorType = checkNotNull(classType.toMaybeFunctionType());
ObjectType instanceType = checkNotNull(constructorType.getInstanceType());
result.setJSType(instanceType);
}
return result;
}
Node createAssign(Node lhs, Node rhs) {
Node result = IR.assign(lhs, rhs);
if (isAddingTypes()) {
result.setJSType(rhs.getJSType());
}
return result;
}
Node createEmptyFunction(JSType type) {
Node result = NodeUtil.emptyFunction();
if (isAddingTypes()) {
checkNotNull(type);
checkArgument(type.isFunctionType(), type);
result.setJSType(checkNotNull(type));
}
return result;
}
Node createFunction(String name, Node paramList, Node body, JSType type) {
Node nameNode = createName(name, type);
Node result = IR.function(nameNode, paramList, body);
if (isAddingTypes()) {
checkArgument(type.isFunctionType(), type);
result.setJSType(type);
}
return result;
}
Node createMemberFunctionDef(String name, Node function) {
// A function used for a member function definition must have an empty name,
// because the name string goes on the MEMBER_FUNCTION_DEF node.
checkArgument(function.getFirstChild().getString().isEmpty(), function);
Node result = IR.memberFunctionDef(name, function);
if (isAddingTypes()) {
// member function definition must share the type of the function that implements it
result.setJSType(function.getJSType());
}
return result;
}
private JSType getNativeType(JSTypeNative nativeType) {
checkNotNull(registry, "registry is null");
return checkNotNull(
registry.getNativeType(nativeType), "native type not found: %s", nativeType);
}
/**
* Look up the correct type for the given name in the given scope.
*
*
Returns the unknown type if no type can be found
*/
private JSType getVarNameType(Scope scope, String name) {
Var var = scope.getVar(name);
JSType type = null;
if (var != null) {
Node nameDefinitionNode = var.getNode();
if (nameDefinitionNode != null) {
type = nameDefinitionNode.getJSType();
}
}
if (type == null) {
// TODO(bradfordcsmith): Consider throwing an error if the type cannot be found.
type = getNativeType(JSTypeNative.UNKNOWN_TYPE);
}
return type;
}
private JSType getJsTypeForProperty(Node receiver, String propertyName) {
// NOTE: we use both findPropertyType and getPropertyType because they are subtly
// different: findPropertyType works on JSType, autoboxing scalars and joining unions,
// but it returns null if the type is not found and does not handle dynamic types of
// Function.prototype.call and .apply; whereas getPropertyType does not autobox nor
// iterate over unions, but it does synthesize the function properties correctly, and
// it returns unknown instead of null if the property is missing.
JSType getpropType = null;
JSType receiverJSType = receiver.getJSType();
if (receiverJSType != null) {
getpropType = receiverJSType.findPropertyType(propertyName);
if (getpropType == null) {
ObjectType receiverObjectType = ObjectType.cast(receiverJSType.autobox());
getpropType =
receiverObjectType == null
? getNativeType(JSTypeNative.UNKNOWN_TYPE)
: receiverObjectType.getPropertyType(propertyName);
}
}
if (getpropType == null) {
getpropType = getNativeType(JSTypeNative.UNKNOWN_TYPE);
}
// TODO(bradfordcsmith): Special case $jscomp.global until we annotate its type correctly.
if (getpropType.isUnknownType()
&& propertyName.equals("global")
&& receiver.matchesQualifiedName("$jscomp")) {
getpropType = getNativeType(JSTypeNative.GLOBAL_THIS);
}
return getpropType;
}
}