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/*
* Copyright 2019 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.modules;
import static com.google.common.base.Preconditions.checkState;
import static com.google.javascript.jscomp.modules.ModuleMapCreator.DOES_NOT_HAVE_EXPORT_WITH_DETAILS;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.javascript.jscomp.AbstractCompiler;
import com.google.javascript.jscomp.JSError;
import com.google.javascript.jscomp.NodeTraversal;
import com.google.javascript.jscomp.NodeTraversal.AbstractPreOrderCallback;
import com.google.javascript.jscomp.deps.ModuleLoader.ModulePath;
import com.google.javascript.jscomp.modules.ClosureRequireProcessor.Require;
import com.google.javascript.jscomp.modules.ModuleMapCreator.ModuleProcessor;
import com.google.javascript.jscomp.modules.ModuleMetadataMap.ModuleMetadata;
import com.google.javascript.rhino.Node;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Processor for goog.module
*
* The namespace of a goog.module contains all named exports, e.g. {@code exports.x = 0}, and any
* 'default export's that assign directly to the `exports` object, e.g. {@code exports = class {}}).
*
*
The bound names include any names imported through a goog.require(Type)/forwardDeclare.
*/
final class ClosureModuleProcessor implements ModuleProcessor {
private static class UnresolvedGoogModule extends UnresolvedModule {
private final ModuleMetadata metadata;
private final String srcFileName;
@Nullable private final ModulePath path;
private final ImmutableMap namespace;
private final ImmutableMap requiresByLocalName;
private final AbstractCompiler compiler;
private Module resolved = null;
UnresolvedGoogModule(
ModuleMetadata metadata,
String srcFileName,
ModulePath path,
ImmutableMap namespace,
ImmutableMap requires,
AbstractCompiler compiler) {
this.metadata = metadata;
this.srcFileName = srcFileName;
this.path = path;
this.namespace = namespace;
this.requiresByLocalName = requires;
this.compiler = compiler;
}
@Nullable
@Override
public ResolveExportResult resolveExport(
ModuleRequestResolver moduleRequestResolver, String exportName) {
if (namespace.containsKey(exportName)) {
return ResolveExportResult.of(namespace.get(exportName));
}
return ResolveExportResult.NOT_FOUND;
}
@Nullable
@Override
public ResolveExportResult resolveExport(
ModuleRequestResolver moduleRequestResolver,
@Nullable String moduleSpecifier,
String exportName,
Set resolveSet,
Set exportStarSet) {
return resolveExport(moduleRequestResolver, exportName);
}
@Override
public Module resolve(
ModuleRequestResolver moduleRequestResolver, @Nullable String moduleSpecifier) {
if (resolved == null) {
// Every import creates a locally bound name.
Map boundNames =
new LinkedHashMap<>(getAllResolvedImports(moduleRequestResolver));
resolved =
Module.builder()
.path(path)
.metadata(metadata)
.namespace(namespace)
.boundNames(ImmutableMap.copyOf(boundNames))
.localNameToLocalExport(ImmutableMap.of())
.closureNamespace(Iterables.getOnlyElement(metadata.googNamespaces()))
.unresolvedModule(this)
.build();
}
return resolved;
}
/** A map from import bound name to binding. */
Map getAllResolvedImports(ModuleRequestResolver moduleRequestResolver) {
Map imports = new HashMap<>();
for (String name : requiresByLocalName.keySet()) {
ResolveExportResult b = resolveImport(moduleRequestResolver, name);
if (b.resolved()) {
imports.put(name, b.getBinding());
}
}
return imports;
}
ResolveExportResult resolveImport(ModuleRequestResolver moduleRequestResolver, String name) {
Require require = requiresByLocalName.get(name);
Import importRecord = require.importRecord();
UnresolvedModule requested = moduleRequestResolver.resolve(importRecord);
if (requested == null) {
return ResolveExportResult.ERROR;
} else if (importRecord.importName().equals(Export.NAMESPACE)) {
// Return a binding based on the other module's metadata.
return ResolveExportResult.of(
Binding.from(
requested.metadata(),
importRecord.nameNode(),
importRecord.moduleRequest(),
require.createdBy()));
} else {
ResolveExportResult result =
requested.resolveExport(
moduleRequestResolver,
importRecord.moduleRequest(),
importRecord.importName(),
new HashSet<>(),
new HashSet<>());
if (!result.found() && !result.hadError()) {
reportInvalidDestructuringRequire(requested, importRecord);
return ResolveExportResult.ERROR;
}
Node forSourceInfo =
importRecord.nameNode() == null ? importRecord.importNode() : importRecord.nameNode();
return result.copy(forSourceInfo, require.createdBy());
}
}
@Override
ModuleMetadata metadata() {
return metadata;
}
@Override
public ImmutableSet getExportedNames(ModuleRequestResolver moduleRequestResolver) {
// Unsupported until such time as it becomes useful
throw new UnsupportedOperationException();
}
@Override
public ImmutableSet getExportedNames(
ModuleRequestResolver moduleRequestResolver, Set visited) {
throw new UnsupportedOperationException();
}
@Override
void reset() {
resolved = null;
}
/** Reports an error given an invalid destructuring require. */
private void reportInvalidDestructuringRequire(
UnresolvedModule requested, Import importRecord) {
String additionalInfo = "";
if (requested instanceof UnresolvedGoogModule) {
// Detect some edge cases and given more helpful error messages.
Map exports = ((UnresolvedGoogModule) requested).namespace;
if (exports.containsKey(Export.NAMESPACE)) {
// Can't use destructuring imports on a goog.module with a default export like
// exports = class {
// (even if there is an assignment like `exports.Bar = 0;` later)
additionalInfo =
Strings.lenientFormat( // Use Strings.lenientFormat for GWT/J2CL compatability
"\n"
+ "The goog.module \"%s\" cannot be destructured as it contains a default"
+ " export, not named exports. See %s.",
importRecord.moduleRequest(),
"https://github.com/google/closure-library/wiki/goog.module%3A-an-ES6-module-like-alternative-to-goog.provide#destructuring-imports");
if (mayBeAccidentalDefaultExport(importRecord.importName(), exports)) {
// Give the user a more detailed error message, since this is a tricky edge case.
additionalInfo +=
Strings.lenientFormat(
"\n"
+ "Either use a non-destructuring require or rewrite the goog.module"
+ " \"%s\" to support destructuring requires. For example, consider"
+ " replacing\n"
+ " exports = {%s: [, ...]};\n"
+ "with individual named export assignments like\n"
+ " exports.%s = ;\n",
importRecord.moduleRequest(),
importRecord.importName(),
importRecord.importName());
}
}
}
compiler.report(
JSError.make(
srcFileName,
importRecord.importNode().getLineno(),
importRecord.importNode().getCharno(),
DOES_NOT_HAVE_EXPORT_WITH_DETAILS,
importRecord.importName(),
additionalInfo));
}
}
/**
* Returns whether the user appears to have confused a default export of an object literal with
* the named export object literal shorthand.
*
* Basically, `exports = {foo: 0};`, does /not/ create a 'named export' of 'foo' because 0 is
* not a name. So users cannot destructuring-require `const {foo} = goog.require('the.module');`.
* However, if instead of `0` the user exported a name like `bar`, the user could use a
* destructuring require.
*/
private static boolean mayBeAccidentalDefaultExport(
String importName, Map exports) {
Node defaultExport = exports.get(Export.NAMESPACE).originatingExport().exportNode();
checkState(
defaultExport.matchesName("exports") && defaultExport.getParent().isAssign(),
defaultExport);
Node exportedValue = defaultExport.getNext();
if (!exportedValue.isObjectLit()) {
return false;
}
// Look for `importName` in the exported object literal.
for (Node key : exportedValue.children()) {
if (key.isStringKey() && key.getString().equals(importName)) {
return true;
}
}
return false;
}
private final AbstractCompiler compiler;
public ClosureModuleProcessor(AbstractCompiler compiler) {
this.compiler = compiler;
}
@Override
public UnresolvedModule process(ModuleMetadata metadata, ModulePath path, Node script) {
Preconditions.checkArgument(
script.isScript() || script.isCall(), "Unexpected module root %s", script);
Preconditions.checkArgument(
script.isCall() || path != null, "Non goog.loadModules must have a path");
ModuleProcessingCallback moduleProcessingCallback = new ModuleProcessingCallback(metadata);
NodeTraversal.traverse(compiler, script, moduleProcessingCallback);
return new UnresolvedGoogModule(
metadata,
script.getSourceFileName(),
path,
ImmutableMap.copyOf(moduleProcessingCallback.namespace),
ImmutableMap.copyOf(moduleProcessingCallback.requiresByLocalName),
compiler);
}
/** Traverses a subtree rooted at a module, gathering all exports and requires */
private static class ModuleProcessingCallback extends AbstractPreOrderCallback {
private final ModuleMetadata metadata;
/** The Closure namespace 'a.b.c' from the `goog.module('a.b.c');` statement */
private final String closureNamespace;
// Note: the following two maps are mutable because in some cases, we need to check if a key has
// already been added before trying to add a second.
/** All named exports and explicit assignments of the `exports` object */
private final Map namespace;
/** All required/forwardDeclared local names */
private final Map requiresByLocalName;
/** Whether we've come across an "exports = ..." assignment */
private boolean seenExportsAssignment;
ModuleProcessingCallback(ModuleMetadata metadata) {
this.metadata = metadata;
this.namespace = new LinkedHashMap<>();
this.requiresByLocalName = new LinkedHashMap<>();
this.closureNamespace = Iterables.getOnlyElement(metadata.googNamespaces());
this.seenExportsAssignment = false;
}
@Override
public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
switch (n.getToken()) {
case MODULE_BODY:
case SCRIPT:
case CALL: // Traverse into goog.loadModule calls.
case BLOCK:
return true;
case FUNCTION:
// Only traverse into functions that are the argument of a goog.loadModule call, which is
// the module root. Avoid traversing function declarations like:
// goog.module('a.b'); function (exports) { exports.x = 0; }
return parent.isCall() && parent == metadata.rootNode();
case EXPR_RESULT:
Node expr = n.getFirstChild();
if (expr.isAssign()) {
maybeInitializeExports(expr);
} else if (expr.isGetProp()) {
maybeInitializeExportsStub(expr);
}
return false;
case CONST:
case VAR:
case LET:
// Note that `let` is valid only for `goog.forwardDeclare`.
maybeInitializeRequire(n);
return false;
default:
return false;
}
}
/** If an assignment is to 'exports', adds it to the list of Exports */
private void maybeInitializeExports(Node assignment) {
Node lhs = assignment.getFirstChild();
Node rhs = assignment.getSecondChild();
if (lhs.isName() && lhs.getString().equals("exports")) {
// This may be a 'named exports' or may be a default export.
// It is a 'named export' if and only if it is assigned an object literal w/ string keys,
// whose values are all names.
if (isNamedExportsLiteral(rhs)) {
initializeNamedExportsLiteral(rhs);
} else {
seenExportsAssignment = true;
}
markExportsAssignmentInNamespace(lhs);
} else if (lhs.isGetProp()
&& lhs.getFirstChild().isName()
&& lhs.getFirstChild().getString().equals("exports")) {
String exportedId = lhs.getSecondChild().getString();
addPropertyExport(exportedId, lhs);
}
}
/** Adds stub export declarations `exports.Foo;` to the list of Exports */
private void maybeInitializeExportsStub(Node qname) {
Node owner = qname.getFirstChild();
if (owner.isName() && owner.getString().equals("exports")) {
Node prop = qname.getSecondChild();
String exportedId = prop.getString();
addPropertyExport(exportedId, qname);
}
}
/**
* Adds an explicit namespace export.
*
* Note that all goog.modules create an 'exports' object, but this object is only added to
* the Module namespace if there is an explicit' exports = ...' assignment
*/
private void markExportsAssignmentInNamespace(Node exportsNode) {
namespace.put(
Export.NAMESPACE,
Binding.from(
Export.builder()
.exportName(Export.NAMESPACE)
.exportNode(exportsNode)
.moduleMetadata(metadata)
.closureNamespace(closureNamespace)
.modulePath(metadata.path())
.build(),
exportsNode));
}
private void initializeNamedExportsLiteral(Node objectLit) {
for (Node key : objectLit.children()) {
addPropertyExport(key.getString(), key);
}
}
/** Adds a named export to the list of Exports */
private void addPropertyExport(String exportedId, Node propNode) {
if (seenExportsAssignment) {
// We've seen an assignment "exports = ...", so this is not a named export.
return;
} else if (namespace.containsKey(exportedId)) {
// Ignore duplicate exports - this is an error but checked elsewhere.
return;
}
namespace.put(
exportedId,
Binding.from(
Export.builder()
.exportName(exportedId)
.exportNode(propNode)
.moduleMetadata(metadata)
.closureNamespace(closureNamespace)
.modulePath(metadata.path())
.build(),
propNode));
}
/** Adds a goog.require(Type) or forwardDeclare to the list of {@code requiresByLocalName} */
private void maybeInitializeRequire(Node nameDeclaration) {
for (Require require : ClosureRequireProcessor.getAllRequires(nameDeclaration)) {
requiresByLocalName.putIfAbsent(require.localName(), require);
}
}
}
/**
* Whether this is an assignment to 'exports' that creates named exports.
*
*
* - exports = {a, b}; // named exports
*
- exports = 0; // namespace export
*
- exports = {a: 0, b}; // namespace export
*
*/
private static boolean isNamedExportsLiteral(Node objLit) {
if (!objLit.isObjectLit() || !objLit.hasChildren()) {
return false;
}
for (Node key : objLit.children()) {
if (!key.isStringKey() || key.isQuotedString()) {
return false;
}
if (!key.getFirstChild().isName()) {
return false;
}
}
return true;
}
}