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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.
/*
* Copyright 2009 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.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.javascript.jscomp.graph.GraphvizGraph;
import com.google.javascript.jscomp.graph.LinkedDirectedGraph;
import java.util.List;
/**
* Pass factories and meta-data for native Compiler passes.
*/
public abstract class PassConfig {
// Used by the subclasses.
protected final CompilerOptions options;
private TypedScopeCreator typedScopeCreator;
/** The global typed scope. */
TypedScope topScope = null;
public PassConfig(CompilerOptions options) {
this.options = options;
}
void clearTypedScopeCreator() {
typedScopeCreator = null;
}
void clearTopTypedScope() {
topScope = null;
}
/** Gets the scope creator for typed scopes. */
TypedScopeCreator getTypedScopeCreator() {
return this.typedScopeCreator;
}
TypedScopeCreator getTypedScopeCreator(AbstractCompiler copmiler) {
if (this.typedScopeCreator == null) {
this.typedScopeCreator = new TypedScopeCreator(copmiler);
}
return this.typedScopeCreator;
}
/**
* Gets the global scope, with type information.
*/
TypedScope getTopScope() {
return topScope;
}
/**
* Gets additional checking passes that are run always, even in "whitespace only" mode.
* For very specific cases where processing is required even in a mode which is intended
* not to have any processing - specifically introduced to support goog.module() usage.
*/
protected List getWhitespaceOnlyPasses() {
return ImmutableList.of();
}
/** Gets the transpilation passes */
protected List getTranspileOnlyPasses() {
return ImmutableList.of();
}
/**
* Gets the checking passes to run.
*
* Checking passes revolve around emitting warnings and errors.
* They also may include pre-processor passes needed to do
* error analysis more effectively.
*
* Clients that only want to analyze code (like IDEs) and not emit
* code will only run checks and not optimizations.
*/
protected abstract List getChecks();
/**
* Gets the optimization passes to run.
*
* Optimization passes revolve around producing smaller and faster code.
* They should always run after checking passes.
*/
protected abstract List getOptimizations();
/**
* Gets a graph of the passes run. For debugging.
*/
GraphvizGraph getPassGraph() {
LinkedDirectedGraph graph =
LinkedDirectedGraph.createWithoutAnnotations();
Iterable allPasses =
Iterables.concat(getChecks(), getOptimizations());
String lastPass = null;
String loopStart = null;
for (PassFactory pass : allPasses) {
String passName = pass.getName();
int i = 1;
while (graph.hasNode(passName)) {
passName = pass.getName() + (i++);
}
graph.createNode(passName);
if (loopStart == null && pass.isRunInFixedPointLoop()) {
loopStart = passName;
} else if (loopStart != null && !pass.isRunInFixedPointLoop()) {
graph.connect(lastPass, "loop", loopStart);
loopStart = null;
}
if (lastPass != null) {
graph.connect(lastPass, "", passName);
}
lastPass = passName;
}
return graph;
}
/**
* Create a type-checking pass.
*/
final TypeCheck makeTypeCheck(AbstractCompiler compiler) {
return new TypeCheck(
compiler,
compiler.getReverseAbstractInterpreter(),
compiler.getTypeRegistry(),
topScope,
typedScopeCreator)
.reportUnknownTypes(options.enables(DiagnosticGroup.forType(TypeCheck.UNKNOWN_EXPR_TYPE)))
.reportMissingProperties(
!options.disables(DiagnosticGroup.forType(TypeCheck.INEXISTENT_PROPERTY)));
}
/**
* Insert the given pass factory before the factory of the given name.
*/
static final void addPassFactoryBefore(
List factoryList, PassFactory factory, String passName) {
factoryList.add(
findPassIndexByName(factoryList, passName), factory);
}
/**
* Find a pass factory with the same name as the given one, and replace it.
*/
static final void replacePassFactory(
List factoryList, PassFactory factory) {
factoryList.set(
findPassIndexByName(factoryList, factory.getName()), factory);
}
/**
* Throws an exception if no pass with the given name exists.
*/
private static int findPassIndexByName(
List factoryList, String name) {
for (int i = 0; i < factoryList.size(); i++) {
if (factoryList.get(i).getName().equals(name)) {
return i;
}
}
throw new IllegalArgumentException(
"No factory named '" + name + "' in the factory list");
}
/**
* Find the first pass provider that does not have a delegate.
*/
final PassConfig getBasePassConfig() {
PassConfig current = this;
while (current instanceof PassConfigDelegate) {
current = ((PassConfigDelegate) current).delegate;
}
return current;
}
/** An implementation of PassConfig that just proxies all its method calls into an inner class. */
public static class PassConfigDelegate extends PassConfig {
private final PassConfig delegate;
protected PassConfigDelegate(PassConfig delegate) {
super(delegate.options);
this.delegate = delegate;
}
@Override
protected List getWhitespaceOnlyPasses() {
return delegate.getWhitespaceOnlyPasses();
}
@Override protected List getChecks() {
return delegate.getChecks();
}
@Override protected List getOptimizations() {
return delegate.getOptimizations();
}
@Override protected List getTranspileOnlyPasses() {
return delegate.getTranspileOnlyPasses();
}
@Override TypedScopeCreator getTypedScopeCreator() {
return delegate.getTypedScopeCreator();
}
@Override TypedScope getTopScope() {
return delegate.getTopScope();
}
@Override
void clearTypedScopeCreator() {
delegate.clearTypedScopeCreator();
}
@Override
void clearTopTypedScope() {
delegate.clearTopTypedScope();
}
}
}