com.google.javascript.jscomp.AmbiguateProperties Maven / Gradle / Ivy
/*
* Copyright 2008 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.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.collect.BiMap;
import com.google.common.collect.HashBiMap;
import com.google.common.collect.ImmutableSet;
import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.jscomp.TypeValidator.TypeMismatch;
import com.google.javascript.jscomp.graph.AdjacencyGraph;
import com.google.javascript.jscomp.graph.Annotation;
import com.google.javascript.jscomp.graph.GraphColoring;
import com.google.javascript.jscomp.graph.GraphColoring.GreedyGraphColoring;
import com.google.javascript.jscomp.graph.GraphNode;
import com.google.javascript.jscomp.graph.SubGraph;
import com.google.javascript.rhino.Node;
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 java.util.ArrayList;
import java.util.BitSet;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Renames unrelated properties to the same name, using type information.
* This allows better compression as more properties can be given short names.
*
* Properties are considered unrelated if they are never referenced from the
* same type or from a subtype of each others' types, thus this pass is only
* effective if type checking is enabled.
*
* Example:
*
* Foo.fooprop = 0;
* Foo.fooprop2 = 0;
* Bar.barprop = 0;
*
*
* becomes:
*
*
* Foo.a = 0;
* Foo.b = 0;
* Bar.a = 0;
*
*
*/
class AmbiguateProperties implements CompilerPass {
private static final Logger logger = Logger.getLogger(
AmbiguateProperties.class.getName());
private final AbstractCompiler compiler;
private final List stringNodesToRename = new ArrayList<>();
// Can't use these as property names.
private final char[] reservedCharacters;
/** Map from property name to Property object */
private final Map propertyMap = new HashMap<>();
/** Property names that don't get renamed */
private final Set externedNames;
/** Names to which properties shouldn't be renamed, to avoid name conflicts */
private final Set quotedNames = new HashSet<>();
/** Map from original property name to new name. Only used by tests. */
private Map renamingMap = null;
/**
* Sorts Property objects by their count, breaking ties alphabetically to
* ensure a deterministic total ordering.
*/
private static final Comparator FREQUENCY_COMPARATOR =
new Comparator() {
@Override
public int compare(Property p1, Property p2) {
if (p1.numOccurrences != p2.numOccurrences) {
return p2.numOccurrences - p1.numOccurrences;
}
return p1.oldName.compareTo(p2.oldName);
}
};
/** A map from JSType to a unique representative Integer. */
private BiMap intForType = HashBiMap.create();
/**
* A map from JSType to JSTypeBitSet representing the types related
* to the type.
*/
private Map relatedBitsets = new HashMap<>();
/** A set of types that invalidate properties from ambiguation. */
private final Set invalidatingTypes;
/**
* Prefix of properties to skip renaming. These should be renamed in the
* RenameProperties pass.
*/
static final String SKIP_PREFIX = "JSAbstractCompiler";
AmbiguateProperties(AbstractCompiler compiler,
char[] reservedCharacters) {
Preconditions.checkState(compiler.getLifeCycleStage().isNormalized());
this.compiler = compiler;
this.reservedCharacters = reservedCharacters;
JSTypeRegistry r = compiler.getTypeRegistry();
invalidatingTypes = new HashSet<>(ImmutableSet.of(
r.getNativeType(JSTypeNative.ALL_TYPE),
r.getNativeType(JSTypeNative.FUNCTION_FUNCTION_TYPE),
r.getNativeType(JSTypeNative.FUNCTION_INSTANCE_TYPE),
r.getNativeType(JSTypeNative.FUNCTION_PROTOTYPE),
r.getNativeType(JSTypeNative.GLOBAL_THIS),
r.getNativeType(JSTypeNative.OBJECT_TYPE),
r.getNativeType(JSTypeNative.OBJECT_PROTOTYPE),
r.getNativeType(JSTypeNative.OBJECT_FUNCTION_TYPE),
r.getNativeType(JSTypeNative.TOP_LEVEL_PROTOTYPE)));
for (TypeMismatch mis : compiler.getTypeMismatches()) {
addInvalidatingType(mis.typeA);
addInvalidatingType(mis.typeB);
}
for (TypeMismatch mis : compiler.getImplicitInterfaceUses()) {
addInvalidatingType(mis.typeA);
addInvalidatingType(mis.typeB);
}
externedNames = compiler.getExternProperties();
}
static AmbiguateProperties makePassForTesting(
AbstractCompiler compiler, char[] reservedCharacters) {
AmbiguateProperties ap =
new AmbiguateProperties(compiler, reservedCharacters);
ap.renamingMap = new HashMap<>();
return ap;
}
/**
* Invalidates the given type, so that no properties on it will be renamed.
*/
private void addInvalidatingType(JSType type) {
type = type.restrictByNotNullOrUndefined();
if (type.isUnionType()) {
for (JSType alt : type.toMaybeUnionType().getAlternatesWithoutStructuralTyping()) {
addInvalidatingType(alt);
}
}
invalidatingTypes.add(type);
ObjectType objType = ObjectType.cast(type);
if (objType != null && objType.isInstanceType()) {
invalidatingTypes.add(objType.getImplicitPrototype());
}
}
Map getRenamingMap() {
Preconditions.checkNotNull(renamingMap);
return renamingMap;
}
/** Returns an integer that uniquely identifies a JSType. */
private int getIntForType(JSType type) {
// Templatized types don't exist at runtime, so collapse to raw type
if (type != null && type.isTemplatizedType()) {
type = type.toMaybeTemplatizedType().getReferencedType();
}
if (intForType.containsKey(type)) {
return intForType.get(type).intValue();
}
int newInt = intForType.size() + 1;
intForType.put(type, newInt);
return newInt;
}
@Override
public void process(Node externs, Node root) {
// Find all property references and record the types on which they occur.
// Populate stringNodesToRename, propertyMap, quotedNames.
NodeTraversal.traverseEs6(compiler, root, new ProcessProperties());
ImmutableSet.Builder reservedNames = ImmutableSet.builder()
.addAll(externedNames)
.addAll(quotedNames);
int numRenamedPropertyNames = 0;
int numSkippedPropertyNames = 0;
ArrayList nodes = new ArrayList<>(propertyMap.size());
for (Property prop : propertyMap.values()) {
if (prop.skipAmbiguating) {
++numSkippedPropertyNames;
reservedNames.add(prop.oldName);
} else {
++numRenamedPropertyNames;
nodes.add(new PropertyGraphNode(prop));
}
}
PropertyGraph graph = new PropertyGraph(nodes);
GraphColoring coloring =
new GreedyGraphColoring<>(graph, FREQUENCY_COMPARATOR);
int numNewPropertyNames = coloring.color();
// Generate new names for the properties that will be renamed.
NameGenerator nameGen = new DefaultNameGenerator(
reservedNames.build(), "", reservedCharacters);
String[] colorMap = new String[numNewPropertyNames];
for (int i = 0; i < numNewPropertyNames; ++i) {
colorMap[i] = nameGen.generateNextName();
}
// Translate the color of each Property instance to a name.
for (PropertyGraphNode node : graph.getNodes()) {
node.getValue().newName = colorMap[node.getAnnotation().hashCode()];
if (renamingMap != null) {
renamingMap.put(node.getValue().oldName, node.getValue().newName);
}
}
// Actually assign the new names to the relevant STRING nodes in the AST.
for (Node n : stringNodesToRename) {
String oldName = n.getString();
Property p = propertyMap.get(oldName);
if (p != null && p.newName != null) {
Preconditions.checkState(oldName.equals(p.oldName));
if (!p.newName.equals(oldName)) {
n.setString(p.newName);
compiler.reportCodeChange();
}
}
}
if (logger.isLoggable(Level.FINE)) {
logger.fine("Collapsed " + numRenamedPropertyNames + " properties into "
+ numNewPropertyNames + " and skipped renaming "
+ numSkippedPropertyNames + " properties.");
}
}
private BitSet getRelatedTypesOnNonUnion(JSType type) {
// All of the types we encounter should have been added to the
// relatedBitsets via computeRelatedTypes.
if (relatedBitsets.containsKey(type)) {
return relatedBitsets.get(type);
} else {
throw new RuntimeException("Related types should have been computed for"
+ " type: " + type + " but have not been.");
}
}
/**
* Adds subtypes - and implementors, in the case of interfaces - of the type
* to its JSTypeBitSet of related types. Union types are decomposed into their
* alternative types.
*
* The 'is related to' relationship is best understood graphically. Draw an
* arrow from each instance type to the prototype of each of its
* subclass. Draw an arrow from each prototype to its instance type. Draw an
* arrow from each interface to its implementors. A type is related to another
* if there is a directed path in the graph from the type to other. Thus, the
* 'is related to' relationship is reflexive and transitive.
*
*
Example with Foo extends Bar which extends Baz and Bar implements I:
*
* Foo -> Bar.prototype -> Bar -> Baz.prototype -> Baz
* ^
* |
* I
*
*
* Note that we don't need to correctly handle the relationships between
* functions, because the function type is invalidating (i.e. its properties
* won't be ambiguated).
*/
private void computeRelatedTypes(JSType type) {
if (type.isUnionType()) {
type = type.restrictByNotNullOrUndefined();
if (type.isUnionType()) {
for (JSType alt : type.toMaybeUnionType().getAlternates()) {
computeRelatedTypes(alt);
}
return;
}
}
if (relatedBitsets.containsKey(type)) {
// We only need to generate the bit set once.
return;
}
JSTypeBitSet related = new JSTypeBitSet(intForType.size());
relatedBitsets.put(type, related);
related.set(getIntForType(type));
// A prototype is related to its instance.
if (type.isFunctionPrototypeType()) {
addRelatedInstance(((ObjectType) type).getOwnerFunction(), related);
return;
}
// An instance is related to its subclasses.
FunctionType constructor = type.toObjectType().getConstructor();
if (constructor != null && constructor.getSubTypes() != null) {
for (FunctionType subType : constructor.getSubTypes()) {
addRelatedInstance(subType, related);
}
}
// An interface is related to its implementors.
for (FunctionType implementor : compiler.getTypeRegistry()
.getDirectImplementors(type.toObjectType())) {
addRelatedInstance(implementor, related);
}
}
/**
* Adds the instance of the given constructor, its implicit prototype and all
* its related types to the given bit set.
*/
private void addRelatedInstance(
FunctionType constructor, JSTypeBitSet related) {
// TODO(user): A constructor which doesn't have an instance type
// (e.g. it's missing the @constructor annotation) should be an invalidating
// type which doesn't reach this code path.
if (constructor.hasInstanceType()) {
ObjectType instanceType = constructor.getInstanceType();
related.set(getIntForType(instanceType.getImplicitPrototype()));
computeRelatedTypes(instanceType);
related.or(relatedBitsets.get(instanceType));
}
}
class PropertyGraph implements AdjacencyGraph {
private final ArrayList nodes;
PropertyGraph(ArrayList nodes) {
this.nodes = nodes;
}
@Override
public List getNodes() {
return nodes;
}
@Override
public GraphNode getNode(Property property) {
throw new RuntimeException("PropertyGraph#getNode is never called.");
}
@Override
public SubGraph newSubGraph() {
return new PropertySubGraph();
}
@Override
public void clearNodeAnnotations() {
for (PropertyGraphNode node : nodes) {
node.setAnnotation(null);
}
}
@Override
public int getWeight(Property value) {
return value.numOccurrences;
}
}
/**
* A {@link SubGraph} that represents properties. The related types of
* the properties are used to efficiently calculate adjacency information.
*/
class PropertySubGraph implements SubGraph {
/** Types related to properties referenced in this subgraph. */
JSTypeBitSet relatedTypes = new JSTypeBitSet(intForType.size());
/**
* Returns true if prop is in an independent set from all properties in this
* sub graph. That is, if none of its related types intersects with the
* related types for this sub graph.
*/
@Override
public boolean isIndependentOf(Property prop) {
return !relatedTypes.intersects(prop.relatedTypes);
}
/**
* Adds the node to the sub graph, adding all its related types to the
* related types for the sub graph.
*/
@Override
public void addNode(Property prop) {
relatedTypes.or(prop.relatedTypes);
}
}
static class PropertyGraphNode implements GraphNode {
Property property;
protected Annotation annotation;
PropertyGraphNode(Property property) {
this.property = property;
}
@Override
public Property getValue() {
return property;
}
@Override
public Annotation getAnnotation() {
return annotation;
}
@Override
public void setAnnotation(Annotation data) {
annotation = data;
}
}
/** Finds all property references, recording the types on which they occur. */
private class ProcessProperties extends AbstractPostOrderCallback {
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
switch (n.getToken()) {
case GETPROP: {
Node propNode = n.getSecondChild();
JSType jstype = getJSType(n.getFirstChild());
maybeMarkCandidate(propNode, jstype);
break;
}
case CALL: {
Node target = n.getFirstChild();
if (!target.isQualifiedName()) {
break;
}
String renameFunctionName = target.getOriginalQualifiedName();
if (renameFunctionName != null
&& compiler.getCodingConvention().isPropertyRenameFunction(renameFunctionName)) {
int childCount = n.getChildCount();
if (childCount != 2 && childCount != 3) {
compiler.report(
JSError.make(
n,
DisambiguateProperties.Warnings.INVALID_RENAME_FUNCTION,
renameFunctionName,
" Must be called with 1 or 2 arguments."));
break;
}
Node propName = n.getSecondChild();
if (!propName.isString()) {
compiler.report(
JSError.make(
n,
DisambiguateProperties.Warnings.INVALID_RENAME_FUNCTION,
renameFunctionName,
" The first argument must be a string literal."));
break;
}
if (propName.getString().contains(".")) {
compiler.report(
JSError.make(
n,
DisambiguateProperties.Warnings.INVALID_RENAME_FUNCTION,
renameFunctionName,
" The first argument must not be a property path."));
break;
}
JSType jstype = getJSType(n.getSecondChild());
maybeMarkCandidate(propName, jstype);
} else if (NodeUtil.isObjectDefinePropertiesDefinition(n)) {
Node typeObj = n.getSecondChild();
JSType jstype = getJSType(typeObj);
Node objectLiteral = typeObj.getNext();
if (!objectLiteral.isObjectLit()) {
break;
}
for (Node key : objectLiteral.children()) {
if (key.isQuotedString()) {
quotedNames.add(key.getString());
} else {
maybeMarkCandidate(key, jstype);
}
}
}
break;
}
case OBJECTLIT:
// Object.defineProperties literals are handled at the CALL node.
if (n.getParent().isCall()
&& NodeUtil.isObjectDefinePropertiesDefinition(n.getParent())) {
break;
}
// The children of an OBJECTLIT node are keys, where the values
// are the children of the keys.
JSType jstype = getJSType(n);
for (Node key = n.getFirstChild(); key != null; key = key.getNext()) {
// We only want keys that were unquoted.
// Keys are STRING, GET, SET
if (!key.isQuotedString()) {
maybeMarkCandidate(key, jstype);
} else {
// Ensure that we never rename some other property in a way
// that could conflict with this quoted key.
quotedNames.add(key.getString());
}
}
break;
case GETELEM:
// If this is a quoted property access (e.g. x['myprop']), we need to
// ensure that we never rename some other property in a way that
// could conflict with this quoted name.
Node child = n.getLastChild();
if (child.isString()) {
quotedNames.add(child.getString());
}
break;
default:
break;
}
}
/**
* If a property node is eligible for renaming, stashes a reference to it
* and increments the property name's access count.
*
* @param n The STRING node for a property
*/
private void maybeMarkCandidate(Node n, JSType type) {
String name = n.getString();
if (!externedNames.contains(name)) {
stringNodesToRename.add(n);
recordProperty(name, type);
}
}
private Property recordProperty(String name, JSType type) {
Property prop = getProperty(name);
prop.addType(type);
return prop;
}
}
/** Returns true if properties on this type should not be renamed. */
private boolean isInvalidatingType(JSType type) {
if (type.isUnionType()) {
type = type.restrictByNotNullOrUndefined();
if (type.isUnionType()) {
for (JSType alt : type.toMaybeUnionType().getAlternates()) {
if (isInvalidatingType(alt)) {
return true;
}
}
return false;
}
}
ObjectType objType = ObjectType.cast(type);
return objType == null
|| invalidatingTypes.contains(objType)
|| !objType.hasReferenceName()
|| objType.isUnknownType()
|| objType.isEmptyType() /* unresolved types */
|| objType.isEnumType()
|| objType.autoboxesTo() != null;
}
private Property getProperty(String name) {
Property prop = propertyMap.get(name);
if (prop == null) {
prop = new Property(name);
propertyMap.put(name, prop);
}
return prop;
}
/**
* This method gets the JSType from the Node argument and verifies that it is
* present.
*/
private JSType getJSType(Node n) {
if (n == null) {
return compiler.getTypeRegistry().getNativeType(JSTypeNative.UNKNOWN_TYPE);
}
JSType jsType = n.getJSType();
if (jsType == null) {
// TODO(user): This branch indicates a compiler bug, not worthy of
// halting the compilation but we should log this and analyze to track
// down why it happens. This is not critical and will be resolved over
// time as the type checker is extended.
return compiler.getTypeRegistry().getNativeType(JSTypeNative.UNKNOWN_TYPE);
} else {
return jsType;
}
}
/** Encapsulates the information needed for renaming a property. */
private class Property {
final String oldName;
String newName;
int numOccurrences;
boolean skipAmbiguating;
JSTypeBitSet relatedTypes = new JSTypeBitSet(intForType.size());
Property(String name) {
this.oldName = name;
// Properties with this suffix are handled in RenameProperties.
if (name.startsWith(SKIP_PREFIX)) {
skipAmbiguating = true;
}
}
/** Add this type to this property, calculating */
void addType(JSType newType) {
if (skipAmbiguating) {
return;
}
++numOccurrences;
if (newType.isUnionType()) {
newType = newType.restrictByNotNullOrUndefined();
if (newType.isUnionType()) {
for (JSType alt : newType.toMaybeUnionType().getAlternatesWithoutStructuralTyping()) {
addNonUnionType(alt);
}
return;
}
}
addNonUnionType(newType);
}
private void addNonUnionType(JSType newType) {
if (skipAmbiguating || isInvalidatingType(newType)) {
skipAmbiguating = true;
return;
}
if (!relatedTypes.get(getIntForType(newType))) {
computeRelatedTypes(newType);
relatedTypes.or(getRelatedTypesOnNonUnion(newType));
}
}
}
// A BitSet that stores type info. Adds pretty-print routines.
private class JSTypeBitSet extends BitSet {
private static final long serialVersionUID = 1L;
private JSTypeBitSet(int size) {
super(size);
}
private JSTypeBitSet() {
super();
}
/**
* Pretty-printing, for diagnostic purposes.
*/
@Override
public String toString() {
int from = 0;
int current = 0;
List types = new ArrayList<>();
while (-1 != (current = nextSetBit(from))) {
types.add(intForType.inverse().get(current).toString());
from = current + 1;
}
return Joiner.on(" && ").join(types);
}
}
}