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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 2007 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.collect.LinkedHashMultimap;
import com.google.common.collect.Multimap;
import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
import com.google.javascript.jscomp.NodeTraversal.Callback;
import com.google.javascript.rhino.Node;
import java.util.HashSet;
import java.util.Set;
/**
* Finds all method declarations and pulls them into data structures
* for use during cleanups such as arity checks or inlining.
*
*/
abstract class MethodCompilerPass implements CompilerPass {
/** List of methods defined in externs */
final Set externMethods = new HashSet<>();
/** List of extern methods without signatures that we can't warn about */
final Set externMethodsWithoutSignatures = new HashSet<>();
/** List of property names that may not be methods */
final Set nonMethodProperties = new HashSet<>();
// Use a linked map here to keep the output deterministic. Otherwise,
// the choice of method bodies is random when multiple identical definitions
// are found which causes problems in the source maps.
final Multimap methodDefinitions =
LinkedHashMultimap.create();
final AbstractCompiler compiler;
/**
* The signature storage is provided by the implementing class.
*/
interface SignatureStore {
public void reset();
public void addSignature(
String functionName, Node functionNode, String sourceFile);
public void removeSignature(String functionName);
}
MethodCompilerPass(AbstractCompiler compiler) {
this.compiler = compiler;
}
@Override
public void process(Node externs, Node root) {
externMethods.clear();
externMethodsWithoutSignatures.clear();
getSignatureStore().reset();
methodDefinitions.clear();
if (externs != null) {
NodeTraversal.traverseEs6(compiler, externs, new GetExternMethods());
}
NodeTraversal.traverseRootsEs6(compiler, new GatherSignatures(), externs, root);
NodeTraversal.traverseRootsEs6(compiler, getActingCallback(), externs, root);
}
/**
* Subclasses should return a callback that does the actual work they
* want to perform given the computed list of method signatures
*/
abstract Callback getActingCallback();
/**
* Subclasses should return a SignatureStore for storing discovered
* signatures.
*/
abstract SignatureStore getSignatureStore();
/**
* Adds a node that may represent a function signature (if it's a function
* itself or the name of a function).
*/
private void addPossibleSignature(String name, Node node, NodeTraversal t) {
if (node.isFunction()) {
// The node we're looking at is a function, so we can add it directly
addSignature(name, node, t.getSourceName());
} else {
nonMethodProperties.add(name);
}
}
private void addSignature(String name, Node function, String fnSourceName) {
if (externMethodsWithoutSignatures.contains(name)) {
return;
}
getSignatureStore().addSignature(name, function, fnSourceName);
methodDefinitions.put(name, function);
}
/**
* Gathers methods from the externs file. Methods that are listed there but
* do not have a signature are flagged to be ignored when doing arity checks.
* Methods that do include signatures will be checked.
*/
private class GetExternMethods extends AbstractPostOrderCallback {
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
switch (n.getToken()) {
case GETPROP:
case GETELEM: {
Node dest = n.getSecondChild();
if (!dest.isString()) {
return;
}
String name = dest.getString();
// We have a signature. Parse tree of the form:
// assign <- parent
// getprop <- n
// name methods
// string setTimeout
// function
if (parent.isAssign() &&
parent.getFirstChild() == n &&
n.getNext().isFunction()) {
addSignature(name, n.getNext(), t.getSourceName());
} else {
getSignatureStore().removeSignature(name);
externMethodsWithoutSignatures.add(name);
}
externMethods.add(name);
} break;
case OBJECTLIT: {
for (Node key = n.getFirstChild(); key != null; key = key.getNext()) {
Node value = key.getFirstChild();
String name = key.getString();
if (key.isStringKey()
&& value.isFunction()) {
addSignature(name, value, t.getSourceName());
} else {
getSignatureStore().removeSignature(name);
externMethodsWithoutSignatures.add(name);
}
externMethods.add(name);
}
} break;
default:
break;
}
}
}
/**
* Gather signatures from the source to be compiled.
*/
private class GatherSignatures extends AbstractPostOrderCallback {
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
switch (n.getToken()) {
case GETPROP:
case GETELEM:
Node dest = n.getSecondChild();
if (dest.isString()) {
if (dest.getString().equals("prototype")) {
processPrototypeParent(t, parent);
} else {
// Static methods of the form Foo.bar = function() {} or
// Static methods of the form Foo.bar = baz (where baz is a
// function name). Parse tree looks like:
// assign <- parent
// getprop <- n
// name Foo
// string bar
// function or name <- n.getNext()
if (parent.isAssign() &&
parent.getFirstChild() == n) {
addPossibleSignature(dest.getString(), n.getNext(), t);
}
}
}
break;
case OBJECTLIT:
for (Node key = n.getFirstChild(); key != null; key = key.getNext()) {
switch (key.getToken()) {
case STRING_KEY:
addPossibleSignature(key.getString(), key.getFirstChild(), t);
break;
case SETTER_DEF:
case GETTER_DEF:
nonMethodProperties.add(key.getString());
break;
default:
throw new IllegalStateException(
"unexpect OBJECTLIT key: " + key);
}
}
break;
default:
break;
}
}
/**
* Processes the parent of a GETPROP prototype, which can either be
* another GETPROP (in the case of Foo.prototype.bar), or can be
* an assignment (in the case of Foo.prototype = ...).
*/
private void processPrototypeParent(NodeTraversal t, Node n) {
switch (n.getToken()) {
// Foo.prototype.getBar = function() { ... } or
// Foo.prototype.getBar = getBaz (where getBaz is a function)
// parse tree looks like:
// assign <- parent
// getprop <- n
// getprop
// name Foo
// string prototype
// string getBar
// function or name <- assignee
case GETPROP:
case GETELEM:
Node dest = n.getSecondChild();
Node parent = n.getGrandparent();
if (dest.isString() &&
parent.isAssign()) {
Node assignee = parent.getSecondChild();
addPossibleSignature(dest.getString(), assignee, t);
}
break;
default:
break;
}
}
}
}