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Liferay Frontend JS Minifier
/*
* 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.lint;
import static com.google.common.base.Preconditions.checkArgument;
import com.google.common.collect.ImmutableSet;
import com.google.javascript.jscomp.AbstractCompiler;
import com.google.javascript.jscomp.CompilerPass;
import com.google.javascript.jscomp.DiagnosticType;
import com.google.javascript.jscomp.JSError;
import com.google.javascript.jscomp.NodeTraversal;
import com.google.javascript.jscomp.NodeUtil;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.QualifiedName;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Walks the AST looking for usages of qualified names, and 'goog.require's of those names. Then,
* reconciles the two lists, and reports warning for any unnecessary require statements.
*/
public class CheckExtraRequires extends NodeTraversal.AbstractPostOrderCallback
implements CompilerPass {
private final AbstractCompiler compiler;
// Keys are the local name of a required namespace. Values are the goog.require CALL node.
private final Map requires = new HashMap<>();
// Adding an entry to usages indicates that the name (either a fully qualified or local name)
// is used and can be required. Note that since usages are name-based and not scoped, any usage
// that shadows an unused require in that file will cause the extra require warning to be missed.
private final Set usages = new HashSet<>();
/**
* This is only relevant for the standalone CheckExtraRequires run. This is used to restrict the
* linter rule only for the modules listed in this set
*/
@Nullable private final ImmutableSet requiresToRemove;
public static final DiagnosticType EXTRA_REQUIRE_WARNING =
DiagnosticType.disabled(
"JSC_EXTRA_REQUIRE_WARNING", "extra require: ''{0}'' is never referenced in this file");
// TODO(b/130215517): This should eventually be removed and exceptions supressed
private static final ImmutableSet DEFAULT_EXTRA_NAMESPACES =
ImmutableSet.of(
"goog.testing.asserts", "goog.testing.jsunit", "goog.testing.JsTdTestCaseAdapter");
/**
* @param requiresToRemove providing a non-null set to this parameter will result in only removing
* the goog.requires that are in this set. If this is null, it will attempt to remove all the
* unnecessary requires.
*/
public CheckExtraRequires(
AbstractCompiler compiler, @Nullable ImmutableSet requiresToRemove) {
this.compiler = compiler;
this.requiresToRemove = requiresToRemove;
}
@Override
public void process(Node externs, Node root) {
reset();
NodeTraversal.traverse(compiler, root, this);
}
private String extractNamespace(Node call, String... primitiveNames) {
Node callee = call.getFirstChild();
if (!callee.isGetProp()) {
return null;
}
for (String primitiveName : primitiveNames) {
if (callee.matchesQualifiedName(primitiveName)) {
Node target = callee.getNext();
if (target != null && target.isStringLit()) {
return target.getString();
}
}
}
return null;
}
private String extractNamespaceIfRequire(Node call) {
return extractNamespace(call, "goog.require", "goog.requireType");
}
private String extractNamespaceIfForwardDeclare(Node call) {
return extractNamespace(call, "goog.forwardDeclare");
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
maybeAddJsDocUsages(n);
switch (n.getToken()) {
case NAME:
if (!NodeUtil.isLValue(n) && !parent.isGetProp() && !parent.isImportSpec()) {
visitQualifiedName(n);
}
break;
case GETPROP:
// If parent is a GETPROP, they will handle all the usages.
if (!parent.isGetProp() && n.isQualifiedName()) {
visitQualifiedName(n);
}
break;
case CALL:
visitCallNode(n, parent);
break;
case SCRIPT:
visitScriptNode();
reset();
break;
case IMPORT:
visitImportNode(n);
break;
default:
break;
}
}
private void reset() {
this.usages.clear();
this.requires.clear();
}
private void visitScriptNode() {
// For every goog.require, check that there is a usage and warn if there is not.
for (Map.Entry entry : requires.entrySet()) {
String require = entry.getKey();
Node call = entry.getValue();
if (!usages.contains(require)
&& (requiresToRemove == null || requiresToRemove.contains(require))) {
reportExtraRequireWarning(call, require);
}
}
}
private void reportExtraRequireWarning(Node call, String require) {
if (DEFAULT_EXTRA_NAMESPACES.contains(require)) {
return;
}
JSDocInfo jsDoc = NodeUtil.getBestJSDocInfo(call);
if (jsDoc != null && jsDoc.getSuppressions().contains("extraRequire")) {
// There is a @suppress {extraRequire} on the call node or its enclosing statement.
// This is one of the acceptable places for a @suppress, per
// https://github.com/google/closure-compiler/wiki/@suppress-annotations
return;
}
compiler.report(JSError.make(call, EXTRA_REQUIRE_WARNING, require));
}
/**
* @param localName The name that should be used in this file.
*
* Require style | localName
* -------------------------------------|----------
* goog.require('foo.bar'); | foo.bar
* var bar = goog.require('foo.bar'); | bar
* var {qux} = goog.require('foo.bar'); | qux
* import {qux} from 'foo.bar'; | qux
*
*/
private void visitRequire(String localName, Node node) {
requires.putIfAbsent(localName, node);
}
private void visitImportNode(Node importNode) {
Node defaultImport = importNode.getFirstChild();
if (defaultImport.isName()) {
visitRequire(defaultImport.getString(), importNode);
}
Node namedImports = defaultImport.getNext();
if (namedImports.isImportSpecs()) {
for (Node importSpec = namedImports.getFirstChild();
importSpec != null;
importSpec = importSpec.getNext()) {
visitRequire(importSpec.getLastChild().getString(), importNode);
}
}
}
private void visitForwardDeclare(String namespace, Node forwardDeclareCall, Node parent) {
visitGoogRequire(namespace, forwardDeclareCall, parent);
}
private void visitGoogRequire(String namespace, Node googRequireCall, Node parent) {
if (parent.isName()) {
visitRequire(parent.getString(), googRequireCall);
} else if (parent.isDestructuringLhs() && parent.getFirstChild().isObjectPattern()) {
if (parent.getFirstChild().hasChildren()) {
for (Node stringKey = parent.getFirstFirstChild();
stringKey != null;
stringKey = stringKey.getNext()) {
Node importName = stringKey.getFirstChild();
if (!importName.isName()) {
// invalid reported elsewhere
continue;
}
visitRequire(importName.getString(), importName);
}
} else {
visitRequire(namespace, googRequireCall);
}
} else {
visitRequire(namespace, googRequireCall);
}
}
private static final QualifiedName GOOG_MODULE_GET = QualifiedName.of("goog.module.get");
private void visitCallNode(Node call, Node parent) {
String required = extractNamespaceIfRequire(call);
if (required != null) {
visitGoogRequire(required, call, parent);
return;
}
String declare = extractNamespaceIfForwardDeclare(call);
if (declare != null) {
visitForwardDeclare(declare, call, parent);
return;
}
Node callee = call.getFirstChild();
if (GOOG_MODULE_GET.matches(callee) && call.getSecondChild().isStringLit()) {
usages.add(call.getSecondChild().getString());
}
}
private void addUsagesOfAllPrefixes(QualifiedName qualifiedName) {
usages.add(qualifiedName.join());
// For "foo.bar.baz.qux" add usages for "foo.bar.baz.qux", "foo.bar.baz",
// "foo.bar", and "foo" because any of those might be a require that
// we need to include.
while (!qualifiedName.isSimple()) {
qualifiedName = qualifiedName.getOwner();
usages.add(qualifiedName.join());
}
}
private void visitQualifiedName(Node n) {
checkArgument(n.isQualifiedName(), n);
addUsagesOfAllPrefixes(n.getQualifiedNameObject());
}
private void maybeAddJsDocUsages(Node n) {
JSDocInfo info = n.getJSDocInfo();
if (info == null) {
return;
}
info.getTypeExpressions().stream()
.flatMap(e -> e.getAllTypeNames().stream())
.map(QualifiedName::of)
.forEach(this::addUsagesOfAllPrefixes);
}
}