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/*
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Rhino code, released
* May 6, 1999.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1997-1999
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* John Lenz
* Google Inc.
*
* Alternatively, the contents of this file may be used under the terms of
* the GNU General Public License Version 2 or later (the "GPL"), in which
* case the provisions of the GPL are applicable instead of those above. If
* you wish to allow use of your version of this file only under the terms of
* the GPL and not to allow others to use your version of this file under the
* MPL, indicate your decision by deleting the provisions above and replacing
* them with the notice and other provisions required by the GPL. If you do
* not delete the provisions above, a recipient may use your version of this
* file under either the MPL or the GPL.
*
* ***** END LICENSE BLOCK ***** */
package com.google.javascript.rhino.jstype;
import static com.google.javascript.jscomp.base.JSCompObjects.identical;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;
import com.google.javascript.rhino.Node;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;
import org.jspecify.nullness.Nullable;
/**
* Specializes {@link TemplatizedType}s according to provided bindings.
*
* @author [email protected] (John Lenz)
*/
public final class TemplateTypeReplacer implements Visitor {
private final JSTypeRegistry registry;
private final TemplateTypeMap bindings;
private final boolean visitProperties;
// TODO(nickreid): We should only need `useUnknownForMissingBinding`. Keeping two separate bits
// was a quick fix for collapsing two different classes.
private final boolean useUnknownForMissingKeys;
private final boolean useUnknownForMissingValues;
private boolean hasMadeReplacement = false;
private TemplateType keyType;
// initialized to null because it's unused in ~40% of TemplateTypeReplacers
private @Nullable Set seenTypes = null;
/** Creates a replacer for use during {@code TypeInference}. */
public static TemplateTypeReplacer forInference(
JSTypeRegistry registry, Map bindings) {
ImmutableList keys = ImmutableList.copyOf(bindings.keySet());
ImmutableList.Builder values = ImmutableList.builder();
for (TemplateType key : keys) {
JSType value = bindings.get(key);
values.add(value != null ? value : registry.getNativeType(JSTypeNative.UNKNOWN_TYPE));
}
TemplateTypeMap map =
registry.getEmptyTemplateTypeMap().copyWithExtension(keys, values.build());
return new TemplateTypeReplacer(registry, map, true, true, true);
}
/**
* Creates a replacer that will always totally eliminate {@link TemplateType}s from the
* definitions of the types it performs replacement on.
*
* If a binding for a {@link TemplateType} is required but not provided, `?` will be used.
*/
public static TemplateTypeReplacer forTotalReplacement(
JSTypeRegistry registry, TemplateTypeMap bindings) {
return new TemplateTypeReplacer(registry, bindings, false, false, true);
}
/**
* Creates a replacer that may not totally eliminate {@link TemplateType}s from the definitions of
* the types it performs replacement on.
*
*
If a binding for a {@link TemplateType} is required but not provided, uses of that type will
* not be replaced.
*/
public static TemplateTypeReplacer forPartialReplacement(
JSTypeRegistry registry, TemplateTypeMap bindings) {
return new TemplateTypeReplacer(registry, bindings, false, false, false);
}
private TemplateTypeReplacer(
JSTypeRegistry registry,
TemplateTypeMap bindings,
boolean visitProperties,
boolean useUnknownForMissingKeys,
boolean useUnknownForMissingValues) {
this.registry = registry;
this.bindings = bindings;
this.visitProperties = visitProperties;
this.useUnknownForMissingKeys = useUnknownForMissingKeys;
this.useUnknownForMissingValues = useUnknownForMissingValues;
}
public boolean hasMadeReplacement() {
return this.hasMadeReplacement;
}
private void initSeenTypes() {
if (this.seenTypes == null) {
this.seenTypes = Sets.newIdentityHashSet();
}
}
@Override
public JSType caseNoType(NoType type) {
return type;
}
@Override
public JSType caseEnumElementType(EnumElementType type) {
return type;
}
@Override
public JSType caseAllType() {
return getNativeType(JSTypeNative.ALL_TYPE);
}
@Override
public JSType caseBooleanType() {
return getNativeType(JSTypeNative.BOOLEAN_TYPE);
}
@Override
public JSType caseNoObjectType() {
return getNativeType(JSTypeNative.NO_OBJECT_TYPE);
}
@Override
public JSType caseFunctionType(FunctionType type) {
return guardAgainstCycles(type, this::caseFunctionTypeUnguarded);
}
private JSType caseFunctionTypeUnguarded(FunctionType type) {
if (isNativeFunctionType(type)) {
return type;
}
if (!type.isOrdinaryFunction() && !type.isConstructor()) {
return type;
}
boolean changed = false;
JSType beforeThis = type.getTypeOfThis();
JSType afterThis = coerseToThisType(beforeThis.visit(this));
if (!identical(beforeThis, afterThis)) {
changed = true;
}
JSType beforeReturn = type.getReturnType();
JSType afterReturn = beforeReturn.visit(this);
if (!identical(beforeReturn, afterReturn)) {
changed = true;
}
boolean paramsChanged = false;
int numParams = type.getParameters().size();
FunctionParamBuilder paramBuilder =
numParams == 0 ? null : new FunctionParamBuilder(registry, numParams);
for (int i = 0; i < numParams; i++) {
FunctionType.Parameter parameter = type.getParameters().get(i);
JSType beforeParamType = parameter.getJSType();
JSType afterParamType = beforeParamType.visit(this);
if (!identical(beforeParamType, afterParamType)) {
changed = true;
paramsChanged = true;
// TODO(lharker): we could also lazily create the FunctionParamBuilder here, but that would
// require re-iterating over all previously seen params so unclear it's worth the complexity
if (parameter.isOptional()) {
paramBuilder.addOptionalParams(afterParamType);
} else if (parameter.isVariadic()) {
paramBuilder.addVarArgs(afterParamType);
} else {
paramBuilder.addRequiredParams(afterParamType);
}
} else {
paramBuilder.newParameterFrom(parameter);
}
}
if (changed) {
return type.toBuilder()
.withParameters(paramsChanged ? paramBuilder.build() : type.getParameters())
.withReturnType(afterReturn)
.withTypeOfThis(afterThis)
.withIsAbstract(false) // TODO(b/187989034): Copy this from the source function.
.build();
}
return type;
}
private JSType coerseToThisType(JSType type) {
return type != null ? type : registry.getNativeObjectType(JSTypeNative.UNKNOWN_TYPE);
}
@Override
public JSType caseObjectType(ObjectType objType) {
return guardAgainstCycles(objType, this::caseObjectTypeUnguarded);
}
private JSType caseObjectTypeUnguarded(ObjectType objType) {
if (!visitProperties
|| objType.isNominalType()
|| objType instanceof ProxyObjectType
|| !objType.isRecordType()) {
return objType;
}
boolean changed = false;
RecordTypeBuilder builder = new RecordTypeBuilder(registry);
for (String prop : objType.getOwnPropertyNames()) {
Node propertyNode = objType.getPropertyNode(prop);
JSType beforeType = objType.getPropertyType(prop);
JSType afterType = beforeType.visit(this);
if (!identical(beforeType, afterType)) {
changed = true;
}
builder.addProperty(prop, afterType, propertyNode);
}
if (changed) {
return builder.build();
}
return objType;
}
@Override
public JSType caseTemplatizedType(TemplatizedType type) {
return guardAgainstCycles(type, this::caseTemplatizedTypeUnguarded);
}
private JSType caseTemplatizedTypeUnguarded(TemplatizedType type) {
boolean changed = false;
ObjectType beforeBaseType = type.getReferencedType();
ObjectType afterBaseType = ObjectType.cast(beforeBaseType.visit(this));
if (!identical(beforeBaseType, afterBaseType)) {
changed = true;
}
ImmutableList.Builder builder = ImmutableList.builder();
for (JSType beforeTemplateType : type.getTemplateTypes()) {
JSType afterTemplateType = beforeTemplateType.visit(this);
if (!identical(beforeTemplateType, afterTemplateType)) {
changed = true;
}
builder.add(afterTemplateType);
}
if (changed) {
type = registry.createTemplatizedType(afterBaseType, builder.build());
}
return type;
}
@Override
public JSType caseUnknownType() {
return getNativeType(JSTypeNative.UNKNOWN_TYPE);
}
@Override
public JSType caseNullType() {
return getNativeType(JSTypeNative.NULL_TYPE);
}
@Override
public JSType caseNumberType() {
return getNativeType(JSTypeNative.NUMBER_TYPE);
}
@Override
public JSType caseBigIntType() {
return getNativeType(JSTypeNative.BIGINT_TYPE);
}
@Override
public JSType caseStringType() {
return getNativeType(JSTypeNative.STRING_TYPE);
}
@Override
public JSType caseSymbolType() {
return getNativeType(JSTypeNative.SYMBOL_TYPE);
}
@Override
public JSType caseVoidType() {
return getNativeType(JSTypeNative.VOID_TYPE);
}
@Override
public JSType caseUnionType(UnionType type) {
return guardAgainstCycles(type, this::caseUnionTypeUnguarded);
}
private JSType caseUnionTypeUnguarded(UnionType type) {
boolean changed = false;
List results = new ArrayList<>();
ImmutableList alternates = type.getAlternates();
int alternateCount = alternates.size();
for (int i = 0; i < alternateCount; i++) {
var alternative = alternates.get(i);
JSType replacement = alternative.visit(this);
if (!identical(replacement, alternative)) {
changed = true;
}
results.add(replacement);
}
if (changed) {
return registry.createUnionType(results); // maybe not a union
}
return type;
}
@Override
public JSType caseTemplateType(TemplateType type) {
this.hasMadeReplacement = true;
if (!bindings.hasTemplateKey(type)) {
return useUnknownForMissingKeys ? getNativeType(JSTypeNative.UNKNOWN_TYPE) : type;
}
this.initSeenTypes();
if (seenTypes.contains(type)) {
// If we have already encountered this TemplateType during replacement
// (i.e. there is a reference loop) then return the TemplateType type itself.
return type;
} else if (!bindings.hasTemplateType(type)) {
// If there is no JSType substitution for the TemplateType, return either the
// UNKNOWN_TYPE or the TemplateType type itself, depending on configuration.
return useUnknownForMissingValues ? getNativeType(JSTypeNative.UNKNOWN_TYPE) : type;
} else {
JSType replacement = bindings.getUnresolvedOriginalTemplateType(type);
if (replacement == keyType || isRecursive(type, replacement)) {
// Recursive templated type definition (e.g. T resolved to Foo).
return type;
}
seenTypes.add(type);
JSType visitedReplacement = replacement.visit(this);
seenTypes.remove(type);
Preconditions.checkState(
!identical(visitedReplacement, keyType),
"Trying to replace key %s with the same value",
keyType);
return visitedReplacement;
}
}
private JSType getNativeType(JSTypeNative nativeType) {
return registry.getNativeType(nativeType);
}
private boolean isNativeFunctionType(FunctionType type) {
return type.isNativeObjectType();
}
@Override
public JSType caseNamedType(NamedType type) {
// The internals of a named type aren't interesting.
return type;
}
@Override
public JSType caseProxyObjectType(ProxyObjectType type) {
return guardAgainstCycles(type, this::caseProxyObjectTypeUnguarded);
}
private JSType caseProxyObjectTypeUnguarded(ProxyObjectType type) {
// Be careful not to unwrap a type unless it has changed.
JSType beforeType = type.getReferencedTypeInternal();
JSType replacement = beforeType.visit(this);
if (!identical(replacement, beforeType)) {
return replacement;
}
return type;
}
void setKeyType(TemplateType keyType) {
this.keyType = keyType;
}
/**
* Returns whether the replacement type is a templatized type which contains the current type.
* e.g. current type T is being replaced with Foo
*/
private boolean isRecursive(TemplateType currentType, JSType replacementType) {
// Avoid calling "restrictBy..." here as this method ends up being very hot and
// rebuilding unions is expensive.
TemplatizedType replacementTemplatizedType = null;
if (replacementType.isUnionType()) {
UnionType union = replacementType.toMaybeUnionType();
ImmutableList alternates = union.getAlternates();
int alternatesCount = alternates.size();
for (int i = 0; i < alternatesCount; i++) {
JSType t = alternates.get(i);
if (t.isNullType() || t.isVoidType()) {
continue;
}
if (t.isTemplatizedType()) {
if (replacementTemplatizedType != null) {
// TODO(johnlenz): seems like we should check a union of templatized types for
// recursion but this is the existing behavior.
return false;
} else {
replacementTemplatizedType = t.toMaybeTemplatizedType();
}
} else {
// The union contains a untemplatized type.
return false;
}
}
} else {
replacementTemplatizedType = replacementType.toMaybeTemplatizedType();
}
if (replacementTemplatizedType == null) {
return false;
}
ImmutableList replacementTemplateTypes = replacementTemplatizedType.getTemplateTypes();
int replacementCount = replacementTemplateTypes.size();
for (int i = 0; i < replacementCount; i++) {
JSType replacementTemplateType = replacementTemplateTypes.get(i);
if (replacementTemplateType.isTemplateType()
&& isSameType(currentType, replacementTemplateType.toMaybeTemplateType())) {
return true;
}
}
return false;
}
private boolean isSameType(TemplateType currentType, TemplateType replacementType) {
return identical(currentType, replacementType)
|| identical(currentType, bindings.getUnresolvedOriginalTemplateType(replacementType));
}
private JSType guardAgainstCycles(T type, Function mapper) {
this.initSeenTypes();
if (!this.seenTypes.add(type)) {
return type;
}
try {
return mapper.apply(type);
} finally {
this.seenTypes.remove(type);
}
}
}