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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 com.google.common.base.Preconditions;
import com.google.common.base.Predicates;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Ordering;
import com.google.common.collect.Table;
import com.google.javascript.jscomp.parsing.parser.util.format.SimpleFormat;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.JSDocInfo.Marker;
import com.google.javascript.rhino.JSDocInfo.Visibility;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.SourcePosition;
import com.google.javascript.rhino.StaticRef;
import com.google.javascript.rhino.StaticScope;
import com.google.javascript.rhino.StaticSlot;
import com.google.javascript.rhino.StaticSourceFile;
import com.google.javascript.rhino.StaticSymbolTable;
import com.google.javascript.rhino.jstype.EnumType;
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 com.google.javascript.rhino.jstype.SimpleReference;
import com.google.javascript.rhino.jstype.SimpleSlot;
import com.google.javascript.rhino.jstype.StaticTypedScope;
import com.google.javascript.rhino.jstype.StaticTypedSlot;
import com.google.javascript.rhino.jstype.UnionType;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.TreeSet;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.Nullable;
/**
* A symbol table for people that want to use Closure Compiler as an indexer.
*
* Contains an index of all the symbols in the code within a compilation
* job. The API is designed for people who want to visit all the symbols, rather
* than people who want to lookup a specific symbol by a certain key.
*
* We can use this to combine different types of symbol tables. For example,
* one class might have a {@code StaticSymbolTable} of all variable references,
* and another class might have a {@code StaticSymbolTable} of all type names
* in JSDoc comments. This class allows you to combine them into a unified
* index.
*
* Most passes build their own "partial" symbol table that implements the same
* interface (StaticSymbolTable, StaticSlot, and friends). Individual compiler
* passes usually need more or less metadata about the certainty of symbol
* information. Building a complete symbol table with all the necessary metadata
* for all passes would be too slow. However, as long as these "partial" symbol
* tables implement the proper interfaces, we should be able to add them to this
* symbol table to make it more complete.
*
* If clients want fast lookup, they should build their own wrapper around
* this symbol table that indexes symbols or references by the desired lookup
* key.
*
* By design, when this symbol table creates symbols for types, it tries
* to mimic the symbol table you would get in an OO language. For example,
* the "type Foo" and "the constructor that creates objects of type Foo"
* are the same symbol. The types of "Foo.prototype" and "new Foo()" also
* have the same symbol. Although JSCompiler internally treats these as
* distinct symbols, we assume that most clients will not care about
* the distinction.
*
* @see #addSymbolsFrom For more information on how to write plugins for this
* symbol table.
*
* @author [email protected] (Nick Santos)
*/
public final class SymbolTable {
private static final Logger logger =
Logger.getLogger(SymbolTable.class.getName());
/**
* The name we use for the JavaScript built-in Global object. It's
* anonymous in JavaScript, so we have to give it an invalid identifier
* to avoid conflicts with user-defined property names.
*/
public static final String GLOBAL_THIS = "*global*";
/**
* All symbols in the program, uniquely identified by the node where
* they're declared and their name.
*/
private final Table symbols = HashBasedTable.create();
/**
* All syntactic scopes in the program, uniquely identified by the node where
* they're declared.
*/
private final Map scopes = new LinkedHashMap<>();
/**
* All Nodes with JSDocInfo in the program.
*/
private final List docInfos = new ArrayList<>();
private SymbolScope globalScope = null;
private final AbstractCompiler compiler;
private final JSTypeRegistry registry;
/**
* Clients should get a symbol table by asking the compiler at the end
* of a compilation job.
*/
SymbolTable(AbstractCompiler compiler, JSTypeRegistry registry) {
this.compiler = compiler;
this.registry = registry;
}
public Iterable getReferences(Symbol symbol) {
return Collections.unmodifiableCollection(symbol.references.values());
}
public List getReferenceList(Symbol symbol) {
return ImmutableList.copyOf(symbol.references.values());
}
public Iterable getAllSymbols() {
return Collections.unmodifiableCollection(symbols.values());
}
/**
* Get the symbols in their natural ordering.
* Always returns a mutable list.
*/
public List getAllSymbolsSorted() {
List sortedSymbols = getNaturalSymbolOrdering().sortedCopy(symbols.values());
return sortedSymbols;
}
/**
* Gets the 'natural' ordering of symbols.
*
* Right now, we only guarantee that symbols in the global scope will come
* before symbols in local scopes. After that, the order is deterministic but
* undefined.
*/
public Ordering getNaturalSymbolOrdering() {
return symbolOrdering;
}
public SymbolScope getScope(Symbol slot) {
return slot.scope;
}
public Collection getAllJSDocInfoNodes() {
return Collections.unmodifiableList(docInfos);
}
/**
* Declare a symbol after the main symbol table was constructed.
* Throws an exception if you try to declare a symbol twice.
*/
public Symbol declareInferredSymbol(
SymbolScope scope, String name, Node declNode) {
return declareSymbol(name, null, true, scope, declNode, null);
}
/**
* Gets the scope that contains the given node.
* If {@code n} is a function name, we return the scope that contains the
* function, not the function itself.
*/
public SymbolScope getEnclosingScope(Node n) {
Node current = n.getParent();
if (n.isName() &&
n.getParent().isFunction()) {
current = current.getParent();
}
for (; current != null; current = current.getParent()) {
if (scopes.containsKey(current)) {
return scopes.get(current);
}
}
return null;
}
/**
* If {@code sym} is a function, try to find a Symbol for
* a parameter with the given name.
*
* Returns null if we couldn't find one.
*
* Notice that this just makes a best effort, and may not be able
* to find parameters for non-conventional function definitions.
* For example, we would not be able to find "y" in this code:
*
* var x = x() ? function(y) {} : function(y) {};
*
*/
public Symbol getParameterInFunction(Symbol sym, String paramName) {
SymbolScope scope = getScopeInFunction(sym);
if (scope != null) {
Symbol param = scope.getSlot(paramName);
if (param != null && param.scope == scope) {
return param;
}
}
return null;
}
private SymbolScope getScopeInFunction(Symbol sym) {
FunctionType type = sym.getFunctionType();
if (type == null) {
return null;
}
Node functionNode = type.getSource();
if (functionNode == null) {
return null;
}
return scopes.get(functionNode);
}
/**
* All local scopes are associated with a function, and some functions
* are associated with a symbol. Returns the symbol associated with the given
* scope.
*/
public Symbol getSymbolForScope(SymbolScope scope) {
if (scope.getSymbolForScope() == null) {
scope.setSymbolForScope(findSymbolForScope(scope));
}
return scope.getSymbolForScope();
}
/**
* Find the symbol associated with the given scope.
* Notice that we won't always be able to figure out this association
* dynamically, so sometimes we'll just create the association when we
* create the scope.
*/
private Symbol findSymbolForScope(SymbolScope scope) {
Node rootNode = scope.getRootNode();
if (rootNode.getParent() == null) {
return globalScope.getSlot(GLOBAL_THIS);
}
if (!rootNode.isFunction()) {
return null;
}
String name = NodeUtil.getBestLValueName(
NodeUtil.getBestLValue(rootNode));
return name == null ? null : scope.getParentScope().getQualifiedSlot(name);
}
/**
* Get all symbols associated with the type of the given symbol.
*
* For example, given a variable x declared as
* /* @type {Array|Date} /
* var x = f();
* this will return the constructors for Array and Date.
*/
public Iterable getAllSymbolsForTypeOf(Symbol sym) {
return getAllSymbolsForType(getType(sym));
}
/**
* Returns the global scope.
*/
public SymbolScope getGlobalScope() {
return globalScope;
}
/**
* Gets the symbol for the given constructor or interface.
*/
public Symbol getSymbolDeclaredBy(FunctionType fn) {
Preconditions.checkState(fn.isConstructor() || fn.isInterface());
ObjectType instanceType = fn.getInstanceType();
return getSymbolForName(fn.getSource(), instanceType.getReferenceName());
}
/**
* Gets the symbol for the given enum.
*/
public Symbol getSymbolDeclaredBy(EnumType enumType) {
return getSymbolForName(null,
enumType.getElementsType().getReferenceName());
}
/**
* Gets the symbol for the prototype if this is the symbol for a constructor
* or interface.
*/
public Symbol getSymbolForInstancesOf(Symbol sym) {
FunctionType fn = sym.getFunctionType();
if (fn != null && fn.isNominalConstructor()) {
return getSymbolForInstancesOf(fn);
}
return null;
}
/**
* Gets the symbol for the prototype of the given constructor or interface.
*/
public Symbol getSymbolForInstancesOf(FunctionType fn) {
Preconditions.checkState(fn.isConstructor() || fn.isInterface());
ObjectType pType = fn.getPrototype();
return getSymbolForName(fn.getSource(), pType.getReferenceName());
}
private Symbol getSymbolForName(Node source, String name) {
if (name == null || globalScope == null) {
return null;
}
SymbolScope scope = source == null ?
globalScope : getEnclosingScope(source);
// scope will sometimes be null if one of the type-stripping passes
// was run, and the symbol isn't in the AST anymore.
return scope == null ? null : scope.getQualifiedSlot(name);
}
/**
* Gets all symbols associated with the given type.
* For union types, this may be multiple symbols.
* For instance types, this will return the constructor of
* that instance.
*/
public List getAllSymbolsForType(JSType type) {
if (type == null) {
return ImmutableList.of();
}
UnionType unionType = type.toMaybeUnionType();
if (unionType != null) {
List result = new ArrayList<>(2);
for (JSType alt : unionType.getAlternates()) {
// Our type system never has nested unions.
Symbol altSym = getSymbolForTypeHelper(alt, true);
if (altSym != null) {
result.add(altSym);
}
}
return result;
}
Symbol result = getSymbolForTypeHelper(type, true);
return result == null
? ImmutableList.of() : ImmutableList.of(result);
}
/**
* Gets all symbols associated with the given type.
* If there is more that one symbol associated with the given type,
* return null.
* @param type The type.
* @param linkToCtor If true, we should link instance types back
* to their constructor function. If false, we should link
* instance types back to their prototype. See the comments
* at the top of this file for more information on how
* our internal type system is more granular than Symbols.
*/
private Symbol getSymbolForTypeHelper(JSType type, boolean linkToCtor) {
if (type == null) {
return null;
}
if (type.isGlobalThisType()) {
return globalScope.getSlot(GLOBAL_THIS);
} else if (type.isNominalConstructor()) {
return linkToCtor ?
globalScope.getSlot("Function") :
getSymbolDeclaredBy(type.toMaybeFunctionType());
} else if (type.isFunctionPrototypeType()) {
FunctionType ownerFn = ((ObjectType) type).getOwnerFunction();
if (!ownerFn.isConstructor() && !ownerFn.isInterface()) {
return null;
}
return linkToCtor ?
getSymbolDeclaredBy(ownerFn) :
getSymbolForInstancesOf(ownerFn);
} else if (type.isInstanceType()) {
FunctionType ownerFn = ((ObjectType) type).getConstructor();
return linkToCtor ?
getSymbolDeclaredBy(ownerFn) :
getSymbolForInstancesOf(ownerFn);
} else if (type.isFunctionType()) {
return linkToCtor ?
globalScope.getSlot("Function") :
globalScope.getQualifiedSlot("Function.prototype");
} else if (type.autoboxesTo() != null) {
return getSymbolForTypeHelper(type.autoboxesTo(), linkToCtor);
} else {
return null;
}
}
@SuppressWarnings("unused")
public String toDebugString() {
StringBuilder builder = new StringBuilder();
for (Symbol symbol : getAllSymbols()) {
toDebugString(builder, symbol);
}
return builder.toString();
}
private void toDebugString(StringBuilder builder, Symbol symbol) {
SymbolScope scope = symbol.scope;
if (scope.isGlobalScope()) {
builder.append(
SimpleFormat.format("'%s' : in global scope:\n", symbol.getName()));
} else if (scope.getRootNode() != null) {
builder.append(
SimpleFormat.format("'%s' : in scope %s:%d\n",
symbol.getName(),
scope.getRootNode().getSourceFileName(),
scope.getRootNode().getLineno()));
} else if (scope.getSymbolForScope() != null) {
builder.append(
SimpleFormat.format("'%s' : in scope %s\n", symbol.getName(),
scope.getSymbolForScope().getName()));
} else {
builder.append(
SimpleFormat.format("'%s' : in unknown scope\n", symbol.getName()));
}
int refCount = 0;
for (Reference ref : getReferences(symbol)) {
builder.append(
SimpleFormat.format(" Ref %d: %s:%d\n",
refCount,
ref.getNode().getSourceFileName(),
ref.getNode().getLineno()));
refCount++;
}
}
/**
* Make sure all the given scopes in {@code otherSymbolTable}
* are in this symbol table.
*/
void addScopes(Collection scopes) {
for (S scope : scopes) {
createScopeFrom(scope);
}
}
/** Finds all the scopes and adds them to this symbol table. */
void findScopes(Node externs, Node root) {
NodeTraversal.traverseRoots(
compiler,
new NodeTraversal.AbstractScopedCallback() {
@Override
public void enterScope(NodeTraversal t) {
createScopeFrom(t.getScope());
}
@Override
public void visit(NodeTraversal t, Node n, Node p) {}
},
externs, root);
}
/** Gets all the scopes in this symbol table. */
public Collection getAllScopes() {
return Collections.unmodifiableCollection(scopes.values());
}
/**
* Finds anonymous functions in local scopes, and gives them names
* and symbols. They will show up as local variables with names
* "function%0", "function%1", etc.
*/
public void addAnonymousFunctions() {
TreeSet scopes = new TreeSet<>(lexicalScopeOrdering);
for (SymbolScope scope : getAllScopes()) {
if (scope.isLexicalScope()) {
scopes.add(scope);
}
}
for (SymbolScope scope : scopes) {
addAnonymousFunctionsInScope(scope);
}
}
private void addAnonymousFunctionsInScope(SymbolScope scope) {
Symbol sym = getSymbolForScope(scope);
if (sym == null) {
// JSCompiler has no symbol for this scope. Check to see if it's a
// local function. If it is, give it a name.
if (scope.isLexicalScope() &&
!scope.isGlobalScope() &&
scope.getRootNode() != null &&
!scope.getRootNode().isFromExterns() &&
scope.getParentScope() != null) {
SymbolScope parent = scope.getParentScope();
int count = parent.innerAnonFunctionsWithNames++;
String innerName = "function%" + count;
scope.setSymbolForScope(
declareInferredSymbol(
parent, innerName, scope.getRootNode()));
}
}
}
/**
* Make sure all the symbols and references in {@code otherSymbolTable}
* are in this symbol table.
*
* Uniqueness of symbols and references is determined by the associated
* node.
*
* If multiple symbol tables are mixed in, we do not check for consistency
* between symbol tables. The first symbol we see dictates the type
* information for that symbol.
*/
void addSymbolsFrom(StaticSymbolTable otherSymbolTable) {
for (S otherSymbol : otherSymbolTable.getAllSymbols()) {
String name = otherSymbol.getName();
SymbolScope myScope = createScopeFrom(
otherSymbolTable.getScope(otherSymbol));
StaticRef decl = findBestDeclToAdd(otherSymbolTable, otherSymbol);
Symbol mySymbol = null;
if (decl != null) {
Node declNode = decl.getNode();
// If we have a declaration node, we can ensure the symbol is declared.
mySymbol = isAnySymbolDeclared(name, declNode, myScope);
if (mySymbol == null) {
mySymbol = copySymbolTo(otherSymbol, declNode, myScope);
}
} else {
// If we don't have a declaration node, we won't be able to declare
// a symbol in this symbol table. But we may be able to salvage the
// references if we already have a symbol.
mySymbol = myScope.getOwnSlot(name);
}
if (mySymbol != null) {
for (R otherRef : otherSymbolTable.getReferences(otherSymbol)) {
if (isGoodRefToAdd(otherRef)) {
mySymbol.defineReferenceAt(otherRef.getNode());
}
}
}
}
}
/**
* Checks if any symbol is already declared at the given node and scope
* for the given name. If so, returns it.
*/
private Symbol isAnySymbolDeclared(
String name, Node declNode, SymbolScope scope) {
Symbol sym = symbols.get(declNode, name);
if (sym == null) {
// Sometimes, our symbol tables will disagree on where the
// declaration node should be. In the rare case where this happens,
// trust the existing symbol.
// See SymbolTableTest#testDeclarationDisagreement.
return scope.ownSymbols.get(name);
}
return sym;
}
/** Helper for addSymbolsFrom, to determine the best declaration spot. */
private
StaticRef findBestDeclToAdd(StaticSymbolTable otherSymbolTable, S slot) {
StaticRef decl = slot.getDeclaration();
if (isGoodRefToAdd(decl)) {
return decl;
}
for (R ref : otherSymbolTable.getReferences(slot)) {
if (isGoodRefToAdd(ref)) {
return ref;
}
}
return null;
}
/**
* Helper for addSymbolsFrom, to determine whether a reference is
* acceptable. A reference must be in the normal source tree.
*/
private boolean isGoodRefToAdd(@Nullable StaticRef ref) {
return ref != null && ref.getNode() != null
&& ref.getNode().getStaticSourceFile() != null
&& !Compiler.SYNTHETIC_EXTERNS.equals(
ref.getNode().getStaticSourceFile().getName());
}
private Symbol copySymbolTo(StaticSlot sym, SymbolScope scope) {
return copySymbolTo(sym, sym.getDeclaration().getNode(), scope);
}
private Symbol copySymbolTo(
StaticSlot sym, Node declNode, SymbolScope scope) {
// All symbols must have declaration nodes.
Preconditions.checkNotNull(declNode);
return declareSymbol(
sym.getName(), getType(sym), isTypeInferred(sym), scope, declNode,
sym.getJSDocInfo());
}
private Symbol addSymbol(
String name, JSType type, boolean inferred, SymbolScope scope,
Node declNode) {
Symbol symbol = new Symbol(name, type, inferred, scope);
Symbol replacedSymbol = symbols.put(declNode, name, symbol);
Preconditions.checkState(
replacedSymbol == null,
"Found duplicate symbol %s in global index. Type %s", name, type);
replacedSymbol = scope.ownSymbols.put(name, symbol);
Preconditions.checkState(
replacedSymbol == null,
"Found duplicate symbol %s in its scope. Type %s", name, type);
return symbol;
}
private Symbol declareSymbol(
String name, JSType type, boolean inferred,
SymbolScope scope, Node declNode, JSDocInfo info) {
Symbol symbol = addSymbol(name, type, inferred, scope, declNode);
symbol.setJSDocInfo(info);
symbol.setDeclaration(symbol.defineReferenceAt(declNode));
return symbol;
}
private void removeSymbol(Symbol s) {
SymbolScope scope = getScope(s);
if (scope.ownSymbols.remove(s.getName()) != s) {
throw new IllegalStateException("Symbol not found in scope " + s);
}
if (symbols.remove(s.getDeclaration().getNode(), s.getName()) != s) {
throw new IllegalStateException("Symbol not found in table " + s);
}
}
/**
* Not all symbol tables record references to "namespace" objects.
* For example, if you have:
* goog.dom.DomHelper = function() {};
* The symbol table may not record that as a reference to "goog.dom",
* because that would be redundant.
*/
void fillNamespaceReferences() {
for (Symbol symbol : getAllSymbolsSorted()) {
String qName = symbol.getName();
int rootIndex = qName.indexOf('.');
if (rootIndex == -1) {
continue;
}
Symbol root = symbol.scope.getQualifiedSlot(
qName.substring(0, rootIndex));
if (root == null) {
// In theory, this should never happen, but we fail quietly anyway
// just to be safe.
continue;
}
for (Reference ref : getReferences(symbol)) {
Node currentNode = ref.getNode();
if (!currentNode.isQualifiedName()) {
continue;
}
while (currentNode.isGetProp()) {
currentNode = currentNode.getFirstChild();
String name = currentNode.getQualifiedName();
if (name != null) {
Symbol namespace =
isAnySymbolDeclared(name, currentNode, root.scope);
if (namespace == null) {
namespace = root.scope.getQualifiedSlot(name);
}
if (namespace == null && root.scope.isGlobalScope()) {
namespace = declareSymbol(name,
registry.getNativeType(JSTypeNative.UNKNOWN_TYPE),
true,
root.scope,
currentNode,
null /* JsDoc info */);
}
if (namespace != null) {
namespace.defineReferenceAt(currentNode);
}
}
}
}
}
}
void fillPropertyScopes() {
// Collect all object symbols.
// All symbols that came from goog.module are collected separately because they will have to
// be processed first. See explanation below.
List types = new ArrayList<>();
List googModuleExportTypes = new ArrayList<>();
// Create a property scope for each named type and each anonymous object,
// and populate it with that object's properties.
//
// We notably don't want to create a property scope for 'x' in
// var x = new Foo();
// where x is just an instance of another type.
for (Symbol sym : getAllSymbols()) {
if (needsPropertyScope(sym)) {
if (sym.getName().startsWith("module$exports")) {
googModuleExportTypes.add(sym);
} else {
types.add(sym);
}
}
}
// The order of operations here is significant.
//
// When we add properties to Foo, we'll remove Foo.prototype from
// the symbol table and replace it with a fresh symbol in Foo's
// property scope. So the symbol for Foo.prototype in
// {@code instances} will be stale.
//
// To prevent this, we sort the list by the reverse of the
// default symbol order, which will do the right thing. Essentially going from leaf symbols
// to roots.
//
// Also sorting all symbols is not enough. There is a tricky case with symbols declared in
// goog.module that also has declareLegacyNamespace. Example:
//
// goog.module('x.y');
// goog.module.declareLegacyNamespace();
// exports.foo = function() {};
//
// Symbols are following:
// x.y
// x
// module$exports$x$y.foo
// module$exports$x$y
//
// If we order them in reverse lexicographical order symbols x.y and x will be processed before
// foo. This is wrong as foo is in fact property of x.y namespace. So we must process all
// module$exports$ symbols first. That's why we collected them in separate list.
//
Collections.sort(types, getNaturalSymbolOrdering().reverse());
Collections.sort(googModuleExportTypes, getNaturalSymbolOrdering().reverse());
for (Symbol s : Iterables.concat(googModuleExportTypes, types)) {
createPropertyScopeFor(s);
}
pruneOrphanedNames();
}
private boolean needsPropertyScope(Symbol sym) {
ObjectType type = ObjectType.cast(getType(sym));
if (type == null) {
return false;
}
// Anonymous objects
if (type.getReferenceName() == null) {
return true;
}
// Constructors/prototypes
// Should this check for
// (type.isNominalConstructor() || type.isFunctionPrototypeType())
// ?
if (sym.getName().equals(type.getReferenceName())) {
return true;
}
// Enums
return type.isEnumType()
&& sym.getName().equals(type.toMaybeEnumType().getElementsType().getReferenceName());
}
/**
* Removes symbols where the namespace they're on has been removed.
*
* After filling property scopes, we may have two symbols represented
* in different ways. For example, "A.superClass_.foo" and B.prototype.foo".
*
* This resolves that ambiguity by pruning the duplicates.
* If we have a lexical symbol with a constructor in its property
* chain, then we assume there's also a property path to this symbol.
* In other words, we can remove "A.superClass_.foo" because it's rooted
* at "A", and we built a property scope for "A" above.
*/
void pruneOrphanedNames() {
nextSymbol: for (Symbol s : getAllSymbolsSorted()) {
if (s.isProperty()) {
continue;
}
String currentName = s.getName();
int dot = -1;
while (-1 != (dot = currentName.lastIndexOf('.'))) {
currentName = currentName.substring(0, dot);
Symbol owner = s.scope.getQualifiedSlot(currentName);
if (owner != null
&& getType(owner) != null
&& (getType(owner).isNominalConstructor() ||
getType(owner).isFunctionPrototypeType() ||
getType(owner).isEnumType())) {
removeSymbol(s);
continue nextSymbol;
}
}
}
}
/**
* Create symbols and references for all properties of types in
* this symbol table.
*
* This gets a little bit tricky, because of the way this symbol table
* conflates "type Foo" and "the constructor of type Foo". So if you
* have:
*
*
* SymbolTable symbolTable = for("var x = new Foo();");
* Symbol x = symbolTable.getGlobalScope().getSlot("x");
* Symbol type = symbolTable.getAllSymbolsForType(getType(x)).get(0);
*
*
* Then type.getPropertyScope() will have the properties of the
* constructor "Foo". To get the properties of instances of "Foo",
* you will need to call:
*
*
* Symbol instance = symbolTable.getSymbolForInstancesOf(type);
*
*
* As described at the top of this file, notice that "new Foo()" and
* "Foo.prototype" are represented by the same symbol.
*/
void fillPropertySymbols(Node externs, Node root) {
(new PropertyRefCollector()).process(externs, root);
}
/** Index JSDocInfo. */
void fillJSDocInfo(Node externs, Node root) {
NodeTraversal.traverseRoots(
compiler, new JSDocInfoCollector(compiler.getTypeRegistry()), externs, root);
// Create references to parameters in the JSDoc.
for (Symbol sym : getAllSymbolsSorted()) {
JSDocInfo info = sym.getJSDocInfo();
if (info == null) {
continue;
}
for (Marker marker : info.getMarkers()) {
SourcePosition pos = marker.getNameNode();
if (pos == null) {
continue;
}
Node paramNode = pos.getItem();
String name = paramNode.getString();
Symbol param = getParameterInFunction(sym, name);
if (param == null) {
// There is no reference to this parameter in the actual JavaScript
// code, so we'll try to create a special JsDoc-only symbol in
// a JsDoc-only scope.
SourcePosition typePos = marker.getType();
JSType type = null;
if (typePos != null) {
type = typePos.getItem().getJSType();
}
if (sym.docScope == null) {
sym.docScope = new SymbolScope(null /* root */,
null /* parent scope */, null /* type of this */, sym);
}
// Check to make sure there's no existing symbol. In theory, this
// should never happen, but we check anyway and fail silently
// if our assumptions are wrong. (We do not want to put the symbol
// table into an invalid state).
Symbol existingSymbol =
isAnySymbolDeclared(name, paramNode, sym.docScope);
if (existingSymbol == null) {
declareSymbol(name, type, type == null, sym.docScope, paramNode,
null /* info */);
}
} else {
param.defineReferenceAt(paramNode);
}
}
}
}
/** Records the visibility of each symbol. */
void fillSymbolVisibility(Node externs, Node root) {
CollectFileOverviewVisibility collectPass =
new CollectFileOverviewVisibility(compiler);
collectPass.process(externs, root);
ImmutableMap visibilityMap =
collectPass.getFileOverviewVisibilityMap();
NodeTraversal.traverseRoots(
compiler,
new VisibilityCollector(visibilityMap, compiler.getCodingConvention()),
externs, root);
}
/**
* Build a property scope for the given symbol. Any properties of the symbol
* will be added to the property scope.
*
* It is important that property scopes are created in order from the leaves
* up to the root, so this should only be called from #fillPropertyScopes.
* If you try to create a property scope for a parent before its leaf,
* then the leaf will get cut and re-added to the parent property scope,
* and weird things will happen.
*/
private void createPropertyScopeFor(Symbol s) {
// In order to build a property scope for s, we will need to build
// a property scope for all its implicit prototypes first. This means
// that sometimes we will already have built its property scope
// for a previous symbol.
if (s.propertyScope != null) {
return;
}
SymbolScope parentPropertyScope = null;
ObjectType type = getType(s) == null ? null : getType(s).toObjectType();
if (type == null) {
return;
}
ObjectType proto = type.getParentScope();
if (proto != null && proto != type && proto.getConstructor() != null) {
Symbol parentSymbol = getSymbolForInstancesOf(proto.getConstructor());
if (parentSymbol != null) {
createPropertyScopeFor(parentSymbol);
parentPropertyScope = parentSymbol.getPropertyScope();
}
}
ObjectType instanceType = type;
Iterable propNames = type.getOwnPropertyNames();
if (instanceType.isFunctionPrototypeType()) {
// Guard against modifying foo.prototype when foo is a regular (non-constructor) function.
if (instanceType.getOwnerFunction().hasInstanceType()) {
// Merge the properties of "Foo.prototype" and "new Foo()" together.
instanceType = instanceType.getOwnerFunction().getInstanceType();
propNames = Iterables.concat(propNames, instanceType.getOwnPropertyNames());
}
}
s.setPropertyScope(new SymbolScope(null, parentPropertyScope, type, s));
for (String propName : propNames) {
StaticSlot newProp = instanceType.getSlot(propName);
if (newProp.getDeclaration() == null) {
// Skip properties without declarations. We won't know how to index
// them, because we index things by node.
continue;
}
// We have symbol tables that do not do type analysis. They just try
// to build a complete index of all objects in the program. So we might
// already have symbols for things like "Foo.bar". If this happens,
// throw out the old symbol and use the type-based symbol.
Symbol oldProp = symbols.get(newProp.getDeclaration().getNode(),
s.getName() + "." + propName);
if (oldProp != null) {
removeSymbol(oldProp);
}
// If we've already have an entry in the table for this symbol,
// then skip it. This should only happen if we screwed up,
// and declared multiple distinct properties with the same name
// at the same node. We bail out here to be safe.
if (symbols.get(newProp.getDeclaration().getNode(),
newProp.getName()) != null) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Found duplicate symbol " + newProp);
}
continue;
}
Symbol newSym = copySymbolTo(newProp, s.propertyScope);
if (oldProp != null) {
if (newSym.getJSDocInfo() == null) {
newSym.setJSDocInfo(oldProp.getJSDocInfo());
}
newSym.setPropertyScope(oldProp.propertyScope);
for (Reference ref : oldProp.references.values()) {
newSym.defineReferenceAt(ref.getNode());
}
}
}
}
/**
* Fill in references to "this" variables.
*/
void fillThisReferences(Node externs, Node root) {
(new ThisRefCollector()).process(externs, root);
}
/**
* Given a scope from another symbol table, returns the {@code SymbolScope}
* rooted at the same node. Creates one if it doesn't exist yet.
*/
private SymbolScope createScopeFrom(StaticScope otherScope) {
Node otherScopeRoot = otherScope.getRootNode();
SymbolScope myScope = scopes.get(otherScopeRoot);
if (myScope == null) {
StaticScope otherScopeParent = otherScope.getParentScope();
// If otherScope is a global scope, and we already have a global scope,
// then something has gone seriously wrong.
//
// Not all symbol tables are rooted at the same global node, and
// we do not want to mix and match symbol tables that are rooted
// differently.
if (otherScopeParent == null) {
// The global scope must be created before any local scopes.
Preconditions.checkState(
globalScope == null, "Global scopes found at different roots");
}
myScope = new SymbolScope(
otherScopeRoot,
otherScopeParent == null ? null : createScopeFrom(otherScopeParent),
getTypeOfThis(otherScope),
null);
scopes.put(otherScopeRoot, myScope);
if (myScope.isGlobalScope()) {
globalScope = myScope;
}
}
return myScope;
}
/** A symbol-table entry */
public static final class Symbol extends SimpleSlot {
// Use a linked hash map, so that the results are deterministic
// (and so the declaration always comes first).
private final Map references = new LinkedHashMap<>();
private final SymbolScope scope;
private SymbolScope propertyScope = null;
private Reference declaration = null;
private JSDocInfo docInfo = null;
/**
* Stored separately from {@link #docInfo}, because the visibility stored
* in JSDocInfo is not necessarily authoritative.
*/
@Nullable private Visibility visibility = null;
// A scope for symbols that are only documented in JSDoc.
private SymbolScope docScope = null;
Symbol(String name, JSType type, boolean inferred, SymbolScope scope) {
super(name, type, inferred);
this.scope = scope;
}
@Override
public boolean equals(Object o) {
if (!(o instanceof Symbol)) {
return false;
}
Symbol other = (Symbol) o;
return isTypeInferred() == other.isTypeInferred()
&& Objects.equals(getName(), other.getName())
&& Objects.equals(getType(), other.getType())
&& Objects.equals(scope, other.scope);
}
@Override
public int hashCode() {
return Objects.hash(Boolean.valueOf(isTypeInferred()), getName(), getType(), scope);
}
@Override
public Reference getDeclaration() {
return declaration;
}
public FunctionType getFunctionType() {
return JSType.toMaybeFunctionType(getType());
}
public Reference defineReferenceAt(Node n) {
Reference result = references.get(n);
if (result == null) {
result = new Reference(this, n);
references.put(n, result);
}
return result;
}
/** Sets the declaration node. May only be called once. */
void setDeclaration(Reference ref) {
Preconditions.checkState(this.declaration == null);
this.declaration = ref;
}
public Node getDeclarationNode() {
return declaration == null ? null : declaration.getNode();
}
public String getSourceFileName() {
Node n = getDeclarationNode();
return n == null ? null : n.getSourceFileName();
}
public SymbolScope getPropertyScope() {
return propertyScope;
}
void setPropertyScope(SymbolScope scope) {
this.propertyScope = scope;
if (scope != null) {
this.propertyScope.setSymbolForScope(this);
}
}
@Override
public JSDocInfo getJSDocInfo() {
return docInfo;
}
void setJSDocInfo(JSDocInfo info) {
this.docInfo = info;
}
@Nullable public Visibility getVisibility() {
return this.visibility;
}
void setVisibility(Visibility v) {
this.visibility = v;
}
/** Whether this is a property of another variable. */
public boolean isProperty() {
return scope.isPropertyScope();
}
/** Whether this is a variable in a lexical scope. */
public boolean isLexicalVariable() {
return scope.isLexicalScope();
}
/** Whether this is a variable that's only in JSDoc. */
public boolean isDocOnlyParameter() {
return scope.isDocScope();
}
@Override
public String toString() {
Node n = getDeclarationNode();
int lineNo = n == null ? -1 : n.getLineno();
return getName() + "@" + getSourceFileName() + ":" + lineNo;
}
}
/** Reference */
public static final class Reference extends SimpleReference {
Reference(Symbol symbol, Node node) {
super(symbol, node);
}
}
/** Scope of a symbol */
public static final class SymbolScope {
private final Node rootNode;
private final SymbolScope parent;
private final JSType typeOfThis;
private final Map ownSymbols = new LinkedHashMap<>();
private final int scopeDepth;
// The number of inner anonymous functions that we've given names to.
private int innerAnonFunctionsWithNames = 0;
// The symbol associated with a property scope or doc scope.
private Symbol mySymbol;
SymbolScope(
Node rootNode,
@Nullable SymbolScope parent,
JSType typeOfThis,
Symbol mySymbol) {
this.rootNode = rootNode;
this.parent = parent;
this.typeOfThis = typeOfThis;
this.scopeDepth = parent == null ? 0 : (parent.getScopeDepth() + 1);
this.mySymbol = mySymbol;
}
Symbol getSymbolForScope() {
return mySymbol;
}
void setSymbolForScope(Symbol sym) {
this.mySymbol = sym;
}
/** Gets a unique index for the symbol in this scope. */
public int getIndexOfSymbol(Symbol sym) {
return Iterables.indexOf(
ownSymbols.values(), Predicates.equalTo(sym));
}
Node getRootNode() {
return rootNode;
}
public SymbolScope getParentScope() {
return parent;
}
/**
* Get the slot for a fully-qualified name (e.g., "a.b.c") by trying
* to find property scopes at each part of the path.
*/
public Symbol getQualifiedSlot(String name) {
Symbol fullyNamedSym = getSlot(name);
if (fullyNamedSym != null) {
return fullyNamedSym;
}
int dot = name.lastIndexOf('.');
if (dot != -1) {
Symbol owner = getQualifiedSlot(name.substring(0, dot));
if (owner != null && owner.getPropertyScope() != null) {
return owner.getPropertyScope().getSlot(name.substring(dot + 1));
}
}
return null;
}
public Symbol getSlot(String name) {
Symbol own = getOwnSlot(name);
if (own != null) {
return own;
}
Symbol ancestor = parent == null ? null : parent.getSlot(name);
if (ancestor != null) {
return ancestor;
}
return null;
}
Symbol getOwnSlot(String name) {
return ownSymbols.get(name);
}
public JSType getTypeOfThis() {
return typeOfThis;
}
public boolean isGlobalScope() {
return getParentScope() == null && getRootNode() != null;
}
/**
* Returns whether this is a doc scope. A doc scope is a table for symbols
* that are documented solely within a JSDoc comment.
*/
public boolean isDocScope() {
return getRootNode() == null && mySymbol != null &&
mySymbol.docScope == this;
}
public boolean isPropertyScope() {
return getRootNode() == null && !isDocScope();
}
public boolean isLexicalScope() {
return getRootNode() != null;
}
public int getScopeDepth() {
return scopeDepth;
}
@Override
public String toString() {
Node n = getRootNode();
if (n != null) {
return "Scope@" + n.getSourceFileName() + ":" + n.getLineno();
} else {
return "PropertyScope@" + getSymbolForScope();
}
}
}
private class PropertyRefCollector
extends NodeTraversal.AbstractPostOrderCallback
implements CompilerPass {
@Override
public void process(Node externs, Node root) {
NodeTraversal.traverseRoots(compiler, this, externs, root);
}
private boolean maybeDefineReference(
Node n, String propName, Symbol ownerSymbol) {
// getPropertyScope() will be null in some rare cases where there
// are no extern declarations for built-in types (like Function).
if (ownerSymbol != null && ownerSymbol.getPropertyScope() != null) {
Symbol prop = ownerSymbol.getPropertyScope().getSlot(propName);
if (prop != null) {
prop.defineReferenceAt(n);
return true;
}
}
return false;
}
// Try to find the symbol by its fully qualified name.
private boolean tryDefineLexicalQualifiedNameRef(String name, Node n) {
if (name != null) {
Symbol lexicalSym = getEnclosingScope(n).getQualifiedSlot(name);
if (lexicalSym != null) {
lexicalSym.defineReferenceAt(n);
return true;
}
}
return false;
}
// Try to remove a reference by its fully qualified name.
// If the symbol has no references left, remove it completely.
private void tryRemoveLexicalQualifiedNameRef(String name, Node n) {
if (name != null) {
Symbol lexicalSym = getEnclosingScope(n).getQualifiedSlot(name);
if (lexicalSym != null &&
lexicalSym.isLexicalVariable() &&
lexicalSym.getDeclaration().getNode() == n) {
removeSymbol(lexicalSym);
}
}
}
private boolean maybeDefineTypedReference(
Node n, String propName, JSType owner) {
if (owner.isGlobalThisType()) {
Symbol sym = globalScope.getSlot(propName);
if (sym != null) {
sym.defineReferenceAt(n);
return true;
}
} else if (owner.isNominalConstructor()) {
return maybeDefineReference(
n, propName, getSymbolDeclaredBy(owner.toMaybeFunctionType()));
} else if (owner.isEnumType()) {
return maybeDefineReference(
n, propName, getSymbolDeclaredBy(owner.toMaybeEnumType()));
} else {
boolean defined = false;
for (Symbol ctor : getAllSymbolsForType(owner)) {
if (maybeDefineReference(
n, propName, getSymbolForInstancesOf(ctor))) {
defined = true;
}
}
return defined;
}
return false;
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
// There are two ways to define a property reference:
// 1) As a fully qualified lexical symbol (e.g., x.y)
// 2) As a property of another object (e.g., x's y)
// Property definitions should take precedence over lexical
// definitions. e.g., for "a.b", it's more useful to record
// this as "property b of the type of a", than as "symbol a.b".
if (n.isGetProp()) {
JSType owner = n.getFirstChild().getJSType();
if (owner != null) {
boolean defined = maybeDefineTypedReference(
n, n.getLastChild().getString(), owner);
if (defined) {
tryRemoveLexicalQualifiedNameRef(n.getQualifiedName(), n);
return;
}
}
tryDefineLexicalQualifiedNameRef(n.getQualifiedName(), n);
} else if (n.isStringKey()) {
JSType owner = parent.getJSType();
if (owner != null) {
boolean defined =
maybeDefineTypedReference(n, n.getString(), owner);
if (defined) {
tryRemoveLexicalQualifiedNameRef(
NodeUtil.getBestLValueName(n), n);
return;
}
}
tryDefineLexicalQualifiedNameRef(
NodeUtil.getBestLValueName(n), n);
}
}
}
private class ThisRefCollector
extends NodeTraversal.AbstractScopedCallback
implements CompilerPass {
// The 'this' symbols in the current scope chain.
//
// If we don't know how to declare 'this' in a scope chain,
// then null should be on the stack. But this should be a rare
// occurrence. We should strive to always be able to come up
// with some symbol for 'this'.
private final List thisStack = new ArrayList<>();
@Override
public void process(Node externs, Node root) {
NodeTraversal.traverseRoots(compiler, this, externs, root);
}
@Override
public void enterScope(NodeTraversal t) {
Symbol symbol = null;
if (t.inGlobalScope()) {
// Declare the global this at the first input root.
// This is a bizarre place to put it, but we need some
// location with a real file path (because all symbols
// must have a path).
// Note that root.lastChild.firstChild is the first non-extern input.
Node firstInputRoot = t.getScopeRoot().getLastChild().getFirstChild();
if (firstInputRoot != null) {
symbol = addSymbol(
GLOBAL_THIS,
registry.getNativeType(JSTypeNative.GLOBAL_THIS),
false /* declared */,
globalScope,
firstInputRoot);
symbol.setDeclaration(new Reference(symbol, firstInputRoot));
}
} else {
// Otherwise, declare a "this" property when possible.
SymbolScope scope = scopes.get(t.getScopeRoot());
Preconditions.checkNotNull(scope, "No scope found for node: %s", t.getScopeRoot());
Symbol scopeSymbol = getSymbolForScope(scope);
if (scopeSymbol != null) {
SymbolScope propScope = scopeSymbol.getPropertyScope();
if (propScope != null) {
// If a function is assigned multiple times, we only want
// one addressable "this" symbol.
symbol = propScope.getOwnSlot("this");
if (symbol == null) {
JSType rootType = t.getScopeRoot().getJSType();
FunctionType fnType = rootType == null
? null : rootType.toMaybeFunctionType();
JSType type = fnType == null
? null : fnType.getTypeOfThis();
symbol = addSymbol(
"this",
type,
false /* declared */,
scope,
t.getScopeRoot());
}
// TODO(nicksantos): It's non-obvious where the declaration of
// the 'this' symbol should be. Figure this out later.
}
}
}
thisStack.add(symbol);
}
@Override
public void exitScope(NodeTraversal t) {
thisStack.remove(thisStack.size() - 1);
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
if (!n.isThis()) {
return;
}
Symbol symbol = Iterables.getLast(thisStack);
if (symbol != null) {
Reference ref = symbol.defineReferenceAt(n);
if (symbol.getDeclaration() == null) {
symbol.setDeclaration(ref);
}
}
}
}
/** Collects references to types in JSDocInfo. */
private class JSDocInfoCollector
extends NodeTraversal.AbstractPostOrderCallback {
private final JSTypeRegistry typeRegistry;
private JSDocInfoCollector(JSTypeRegistry registry) {
this.typeRegistry = registry;
}
@Override public void visit(NodeTraversal t, Node n, Node parent) {
if (n.getJSDocInfo() != null) {
// Find references in the JSDocInfo.
JSDocInfo info = n.getJSDocInfo();
docInfos.add(n);
for (Node typeAst : info.getTypeNodes()) {
SymbolScope scope = scopes.get(t.getScopeRoot());
visitTypeNode(
n,
info.getTemplateTypeNames(),
scope == null ? globalScope : scope,
typeAst);
}
}
}
private boolean isNativeSourcelessType(String name) {
switch (name) {
case "null":
case "undefined":
case "void":
return true;
default:
return false;
}
}
public void visitTypeNode(Node refNode, ImmutableList templateTypeNames,
SymbolScope scope, Node n) {
if (n.isString()
&& !isNativeSourcelessType(n.getString())
&& !templateTypeNames.contains(n.getString())) {
Symbol symbol = lookupPossiblyDottedName(scope, n.getString());
if (symbol != null) {
symbol.defineReferenceAt(n);
}
}
for (Node child = n.getFirstChild();
child != null; child = child.getNext()) {
visitTypeNode(refNode, templateTypeNames, scope, child);
}
}
// TODO(peterhal): @template types.
private Symbol lookupPossiblyDottedName(SymbolScope scope, String dottedName) {
// Try the dotted name to start.
String[] names = dottedName.split("\\.");
Symbol result = null;
SymbolScope currentScope = scope;
for (int i = 0; i < names.length; i++) {
String name = names[i];
result = currentScope.getSlot(name);
if (result == null) {
break;
}
if (i < (names.length - 1)) {
currentScope = result.getPropertyScope();
if (currentScope == null) {
result = null;
break;
}
}
}
if (result == null) {
// If we can't find this type, it might be a reference to a
// primitive type (like {string}). Autobox it to check.
JSType type = typeRegistry.getType(dottedName);
JSType autobox = type == null ? null : type.autoboxesTo();
result = autobox == null
? null : getSymbolForTypeHelper(autobox, true);
}
return result;
}
}
/** Collects the visibility information for each name/property. */
private class VisibilityCollector
extends NodeTraversal.AbstractPostOrderCallback {
private final ImmutableMap fileVisibilityMap;
private final CodingConvention codingConvention;
private VisibilityCollector(
ImmutableMap fileVisibilityMap,
CodingConvention codingConvention) {
this.fileVisibilityMap = fileVisibilityMap;
this.codingConvention = codingConvention;
}
@Override public void visit(NodeTraversal t, Node n, Node parent) {
if (n.isName()) {
visitName(t, n);
} else if (n.isGetProp()) {
visitProperty(n, parent);
}
}
private void visitName(NodeTraversal t, Node n) {
Symbol symbol = symbols.get(n, n.getString());
if (symbol == null) {
return;
}
// Visibility already set.
if (symbol.getVisibility() != null) {
return;
}
Var var = t.getScope().getVar(n.getString());
if (var == null) {
return;
}
Visibility v = AccessControlUtils.getEffectiveNameVisibility(
n, var, fileVisibilityMap);
if (v == null) {
return;
}
symbol.setVisibility(v);
}
private void visitProperty(Node getprop, Node parent) {
String propertyName = getprop.getLastChild().getString();
Symbol symbol = symbols.get(getprop, propertyName);
if (symbol == null) {
return;
}
// Visibility already set.
if (symbol.getVisibility() != null) {
return;
}
JSType jsType = getprop.getFirstChild().getJSType();
if (jsType == null) {
return;
}
boolean isOverride = parent.getJSDocInfo() != null
&& parent.isAssign()
&& parent.getFirstChild() == getprop;
if (isOverride) {
// Don't bother with AccessControlUtils for overridden properties.
// AccessControlUtils currently has complicated logic for detecting
// visibility mismatches for overridden properties that is still
// too tightly coupled to CheckAccessControls. TODO(brndn): simplify.
symbol.setVisibility(Visibility.INHERITED);
} else {
ObjectType referenceType = ObjectType.cast(jsType.dereference());
Visibility v = AccessControlUtils.getEffectivePropertyVisibility(
getprop,
referenceType,
fileVisibilityMap,
codingConvention);
if (v == null) {
return;
}
symbol.setVisibility(v);
}
}
}
// Comparators
private final Ordering sourceNameOrdering =
Ordering.natural().nullsFirst();
private final Ordering nodeOrdering = new Ordering() {
@Override
public int compare(Node a, Node b) {
int result = sourceNameOrdering.compare(
a.getSourceFileName(), b.getSourceFileName());
if (result != 0) {
return result;
}
// Source position is a bit mask of line in the top 4 bits, so this
// is a quick way to compare order without computing absolute position.
return a.getSourcePosition() - b.getSourcePosition();
}
};
private final Ordering lexicalScopeOrdering =
new Ordering() {
@Override
public int compare(SymbolScope a, SymbolScope b) {
Preconditions.checkState(a.isLexicalScope() && b.isLexicalScope(),
"We can only sort lexical scopes");
return nodeOrdering.compare(a.getRootNode(), b.getRootNode());
}
};
private final Ordering symbolOrdering = new Ordering() {
@Override
public int compare(Symbol a, Symbol b) {
SymbolScope scopeA = getScope(a);
SymbolScope scopeB = getScope(b);
// More deeply nested symbols should go later.
int result = getLexicalScopeDepth(scopeA) - getLexicalScopeDepth(scopeB);
if (result != 0) {
return result;
}
// After than, just use lexicographic ordering.
// This ensures "a.b" comes before "a.b.c".
return a.getName().compareTo(b.getName());
}
};
/**
* For a lexical scope, just returns the normal scope depth.
*
* For a property scope, returns the number of scopes we have to search
* to find the nearest lexical scope, plus that lexical scope's depth.
*
* For a doc info scope, returns 0.
*/
private int getLexicalScopeDepth(SymbolScope scope) {
if (scope.isLexicalScope() || scope.isDocScope()) {
return scope.getScopeDepth();
} else {
Preconditions.checkState(scope.isPropertyScope());
Symbol sym = scope.getSymbolForScope();
Preconditions.checkNotNull(sym);
return getLexicalScopeDepth(getScope(sym)) + 1;
}
}
private JSType getType(StaticSlot sym) {
if (sym instanceof StaticTypedSlot) {
return ((StaticTypedSlot) sym).getType();
}
return null;
}
private JSType getTypeOfThis(StaticScope s) {
if (s instanceof StaticTypedScope) {
return ((StaticTypedScope) s).getTypeOfThis();
}
return null;
}
private boolean isTypeInferred(StaticSlot sym) {
if (sym instanceof StaticTypedSlot) {
return ((StaticTypedSlot) sym).isTypeInferred();
}
return true;
}
}