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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.

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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;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.javascript.jscomp.ClosurePrimitiveErrors.INVALID_CLOSURE_CALL_SCOPE_ERROR;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Preconditions;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.JSDocInfoBuilder;
import com.google.javascript.rhino.JSTypeExpression;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;

/**
 * Replaces goog.provide calls, removes goog.{require,requireType,forwardDeclare} calls and verifies
 * that each goog.{require,requireType} has a corresponding goog.provide.
 *
 * 

We expect all goog.modules and goog.requires in modules to have been rewritten. This is why * all remaining require/requireType calls must refer to a goog.provide, although the original JS * code may contain goog.requires of a goog.module. * *

This is designed to work during a hotswap pass, under the assumption that no rewriting has * been done of goog.provides and definitions other than this pass. * *

This also annotates all provided namespace definitions `a.b = {};` with {@link * Node#IS_NAMESPACE} so that later passes know they refer to a goog.provide'd namespace. * *

If modules have not been rewritten, this pass also includes legacy Closure module namespaces * in the list of {@link ProvidedName}s. */ class ProcessClosureProvidesAndRequires implements HotSwapCompilerPass { // The root Closure namespace private static final String GOOG = "goog"; private final AbstractCompiler compiler; private final JSModuleGraph moduleGraph; // Use a LinkedHashMap because the goog.provides must be processed in a deterministic order. private final Map providedNames = new LinkedHashMap<>(); private final List unrecognizedRequires = new ArrayList<>(); private final CheckLevel requiresLevel; private final PreprocessorSymbolTable preprocessorSymbolTable; // If this is true, rewriting will not remove any goog.provide or goog.require calls private final boolean preserveGoogProvidesAndRequires; private final List requiresToBeRemoved = new ArrayList<>(); // Whether this instance has already rewritten goog.provides, which can only happen once private boolean hasRewritingOccurred = false; private final Set forwardDeclaresToRemove = new HashSet<>(); private final Set previouslyProvidedDefinitions = new HashSet<>(); ProcessClosureProvidesAndRequires( AbstractCompiler compiler, @Nullable PreprocessorSymbolTable preprocessorSymbolTable, CheckLevel requiresLevel, boolean preserveGoogProvidesAndRequires) { this.compiler = compiler; this.preprocessorSymbolTable = preprocessorSymbolTable; this.moduleGraph = compiler.getModuleGraph(); this.requiresLevel = requiresLevel; this.preserveGoogProvidesAndRequires = preserveGoogProvidesAndRequires; } /** When invoked as compiler pass, we rewrite all provides and requires. */ @Override public void process(Node externs, Node root) { rewriteProvidesAndRequires(externs, root); } @Override public void hotSwapScript(Node scriptRoot, Node originalRoot) { // TODO(bashir): Implement a real hot-swap version instead and make it fully // consistent with the full version. this.compiler.process(this); } /** Collects all goog.provides in the given namespace and warns on invalid code */ Map collectProvidedNames(Node externs, Node root) { if (this.providedNames.isEmpty()) { // goog is special-cased because it is provided in Closure's base library. providedNames.put(GOOG, new ProvidedName(GOOG, null, null, false /* implicit */, false)); NodeTraversal.traverseRoots(compiler, new CollectDefinitions(), externs, root); } return this.providedNames; } /** * Rewrites all provides and requires in the given namespace. * *

Call this instead of {@link #collectProvidedNames(Node, Node)} if you want rewriting. */ void rewriteProvidesAndRequires(Node externs, Node root) { checkState(!hasRewritingOccurred, "Cannot call rewriteProvidesAndRequires twice per instance"); hasRewritingOccurred = true; collectProvidedNames(externs, root); for (ProvidedName pn : providedNames.values()) { pn.replace(); } deleteNamespaceInitializationsFromPreviousProvides(); if (requiresLevel.isOn()) { for (UnrecognizedRequire r : unrecognizedRequires) { checkForLateOrMissingProvide(r); } } for (Node closureRequire : requiresToBeRemoved) { compiler.reportChangeToEnclosingScope(closureRequire); closureRequire.detach(); } for (Node forwardDeclare : forwardDeclaresToRemove) { NodeUtil.deleteNode(forwardDeclare, compiler); } } private void checkForLateOrMissingProvide(UnrecognizedRequire r) { // Both goog.require and goog.requireType must have a matching goog.provide. // However, goog.require must match an earlier goog.provide, while goog.requireType is allowed // to match a later goog.provide. DiagnosticType error; ProvidedName expectedName = providedNames.get(r.namespace); if (expectedName != null && expectedName.firstNode != null) { if (r.isRequireType) { return; } error = ProcessClosurePrimitives.LATE_PROVIDE_ERROR; } else { error = ProcessClosurePrimitives.MISSING_PROVIDE_ERROR; } compiler.report(JSError.make(r.requireNode, requiresLevel, error, r.namespace)); } private class CollectDefinitions implements NodeTraversal.Callback { @Override public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) { // Don't recurse into modules, which cannot have goog.provides. We do need to handle legacy // goog.modules, but we do that quickly here rather than descending all the way into them. // We completely ignore ES modules and CommonJS modules. if ((n.isModuleBody() && n.getParent().getBooleanProp(Node.GOOG_MODULE)) || NodeUtil.isBundledGoogModuleScopeRoot(n)) { Node googModuleCall = n.getFirstChild(); String closureNamespace = googModuleCall.getFirstChild().getSecondChild().getString(); Node maybeLegacyNamespaceCall = googModuleCall.getNext(); if (maybeLegacyNamespaceCall != null && NodeUtil.isGoogModuleDeclareLegacyNamespaceCall(maybeLegacyNamespaceCall)) { processLegacyModuleCall(closureNamespace, googModuleCall, t.getModule()); } return false; } return !n.isModuleBody(); } @Override public void visit(NodeTraversal t, Node n, Node parent) { switch (n.getToken()) { case CALL: Node left = n.getFirstChild(); if (left.isGetProp()) { Node name = left.getFirstChild(); if (name.isName() && GOOG.equals(name.getString())) { // For the sake of simplicity, we report code changes // when we see a provides/requires, and don't worry about // reporting the change when we actually do the replacement. String methodName = name.getNext().getString(); switch (methodName) { case "require": case "requireType": if (validateAliasiablePrimitiveCall(t, n, methodName)) { processRequireCall(t, n, parent); } break; case "provide": if (validateUnaliasablePrimitiveCall(t, n, methodName)) { processProvideCall(t, n, parent); } break; case "forwardDeclare": if (validateAliasiablePrimitiveCall(t, n, methodName)) { processForwardDeclare(n, parent); } break; } } } break; case ASSIGN: case NAME: // If this is an assignment to a provided name, remove the provided object. handleCandidateProvideDefinition(t, n, parent); break; case EXPR_RESULT: handleStubDefinition(t, n); break; case CLASS: if (t.inGlobalHoistScope() && !NodeUtil.isClassExpression(n)) { String name = n.getFirstChild().getString(); ProvidedName pn = providedNames.get(name); if (pn != null) { compiler.report( JSError.make(n, ProcessClosurePrimitives.CLASS_NAMESPACE_ERROR, name)); } } break; case FUNCTION: // If this is a declaration of a provided named function, this is an // error. Hoisted functions will explode if they're provided. if (t.inGlobalHoistScope() && NodeUtil.isFunctionDeclaration(n)) { String name = n.getFirstChild().getString(); ProvidedName pn = providedNames.get(name); if (pn != null) { compiler.report( JSError.make(n, ProcessClosurePrimitives.FUNCTION_NAMESPACE_ERROR, name)); } } break; default: break; } } } /** * Verifies that a) the call is in the global scope and b) the return value is unused * *

This method is for primitives that never return a value. */ private boolean validateUnaliasablePrimitiveCall(NodeTraversal t, Node n, String methodName) { return validatePrimitiveCallWithMessage( t, n, methodName, ProcessClosurePrimitives.CLOSURE_CALL_CANNOT_BE_ALIASED_ERROR); } /** * Verifies that a) the call is in the global scope and b) the return value is unused * *

This method is for primitives that do return a value in modules, but not in scripts/ * goog.provide files */ private boolean validateAliasiablePrimitiveCall(NodeTraversal t, Node n, String methodName) { return validatePrimitiveCallWithMessage( t, n, methodName, ProcessClosurePrimitives.CLOSURE_CALL_CANNOT_BE_ALIASED_OUTSIDE_MODULE_ERROR); } /** * @param methodName list of primitve types classed together with this one * @param invalidAliasingError which DiagnosticType to emit if this call is aliased. this depends * on whether the primitive is sometimes aliasiable in a module or never aliasable. */ private boolean validatePrimitiveCallWithMessage( NodeTraversal t, Node n, String methodName, DiagnosticType invalidAliasingError) { // Ignore invalid primitives if we didn't strip module sugar. if (compiler.getOptions().shouldPreserveGoogModule()) { return true; } if (!t.inGlobalHoistScope()) { compiler.report(JSError.make(n, INVALID_CLOSURE_CALL_SCOPE_ERROR)); return false; } else if (!n.getParent().isExprResult()) { // If the call is in the global hoist scope, but the result is used compiler.report(JSError.make(n, invalidAliasingError, GOOG + "." + methodName)); return false; } return true; } /** Handles a goog.require or goog.requireType call. */ private void processRequireCall(NodeTraversal t, Node n, Node parent) { Node left = n.getFirstChild(); Node arg = left.getNext(); String method = left.getFirstChild().getNext().getString(); if (verifyLastArgumentIsString(left, arg)) { String ns = arg.getString(); ProvidedName provided = providedNames.get(ns); if (provided == null || !provided.isExplicitlyProvided()) { unrecognizedRequires.add(new UnrecognizedRequire(n, ns, method.equals("requireType"))); } else { JSModule providedModule = provided.explicitModule; if (!provided.isFromExterns()) { checkNotNull(providedModule, n); JSModule module = t.getModule(); // A cross-chunk goog.require must match a goog.provide in an earlier chunk. However, a // cross-chunk goog.requireType is allowed to match a goog.provide in a later chunk. if (module != providedModule && !moduleGraph.dependsOn(module, providedModule) && !method.equals("requireType")) { compiler.report( JSError.make( n, ProcessClosurePrimitives.XMODULE_REQUIRE_ERROR, ns, providedModule.getName(), module.getName())); } } } maybeAddNameToSymbolTable(left); maybeAddStringToSymbolTable(arg); // Requires should be removed before further processing. // Some clients run closure pass multiple times, first with // the checks for broken requires turned off. In these cases, we // allow broken requires to be preserved by the first run to // let them be caught in the subsequent run. if (!preserveGoogProvidesAndRequires && (provided != null || requiresLevel.isOn())) { requiresToBeRemoved.add(parent); } } } /** Handles a goog.module that is a legacy namespace. */ private void processLegacyModuleCall(String namespace, Node googModuleCall, JSModule module) { registerAnyProvidedPrefixes(namespace, googModuleCall, module); providedNames.put( namespace, new ProvidedName( namespace, googModuleCall, module, /* explicit= */ true, /* fromPreviousProvide= */ false)); } /** Handles a goog.provide call. */ private void processProvideCall(NodeTraversal t, Node n, Node parent) { checkState(n.isCall()); Node left = n.getFirstChild(); Node arg = left.getNext(); if (verifyProvide(left, arg)) { String ns = arg.getString(); maybeAddNameToSymbolTable(left); maybeAddStringToSymbolTable(arg); if (providedNames.containsKey(ns)) { ProvidedName previouslyProvided = providedNames.get(ns); if (!previouslyProvided.isExplicitlyProvided() || previouslyProvided.isPreviouslyProvided) { previouslyProvided.addProvide(parent, t.getModule(), true); } } else { registerAnyProvidedPrefixes(ns, parent, t.getModule()); providedNames.put( ns, new ProvidedName( ns, parent, t.getModule(), /* explicit= */ true, /* fromPreviousProvide= */ false)); } } } /** * Handles a stub definition for a goog.provided name (e.g. a @typedef or a definition from * externs) * * @param n EXPR_RESULT node. */ private void handleStubDefinition(NodeTraversal t, Node n) { if (!t.inGlobalHoistScope()) { return; } JSDocInfo info = n.getFirstChild().getJSDocInfo(); boolean hasStubDefinition = info != null && (n.isFromExterns() || info.hasTypedefType()); if (hasStubDefinition) { if (n.getFirstChild().isQualifiedName()) { String name = n.getFirstChild().getQualifiedName(); ProvidedName pn = providedNames.get(name); if (pn != null) { n.putBooleanProp(Node.WAS_PREVIOUSLY_PROVIDED, true); pn.addDefinition(n, t.getModule()); } else if (n.getBooleanProp(Node.WAS_PREVIOUSLY_PROVIDED)) { // We didn't find it in the providedNames, but it was previously marked as provided. // This implies we're in hotswap pass and the current typedef is a provided namespace. ProvidedName provided = new ProvidedName(name, n, t.getModule(), true, true); providedNames.put(name, provided); provided.addDefinition(n, t.getModule()); } } } } /** Handles a candidate definition for a goog.provided name. */ private void handleCandidateProvideDefinition(NodeTraversal t, Node n, Node parent) { if (t.inGlobalHoistScope()) { String name = null; if (n.isName() && NodeUtil.isNameDeclaration(parent)) { name = n.getString(); } else if (n.isAssign() && parent.isExprResult()) { name = n.getFirstChild().getQualifiedName(); } if (name != null) { if (parent.getBooleanProp(Node.IS_NAMESPACE)) { // TODO(b/128361464): stop including goog.module exports in this case. processProvideFromPreviousPass(t, name, parent); } else { ProvidedName pn = providedNames.get(name); if (pn != null) { pn.addDefinition(parent, t.getModule()); } } } } } /** * Removes duplicate initializations of goog.provided namespaces created by previous passes * *

Should be called after calling {@link ProvidedName#replace()} on all provided names.. */ private void deleteNamespaceInitializationsFromPreviousProvides() { for (Node name : previouslyProvidedDefinitions) { name.detach(); } } /** * Processes the output of processed-provide from a previous pass. This will update our data * structures in the same manner as if the provide had been processed in this pass. * *

TODO(b/128120127): delete this method */ private void processProvideFromPreviousPass(NodeTraversal t, String name, Node parent) { JSModule module = t.getModule(); if (providedNames.containsKey(name)) { ProvidedName provided = providedNames.get(name); provided.addDefinition(parent, module); if (isNamespacePlaceholder(parent)) { // Remove this later if it is a simple object literal. Replacing the corresponding // ProvidedName will create a new definition. // Don't add this as a 'definition' of the provided name to support pushing provides // into earlier modules. previouslyProvidedDefinitions.add(parent); } } else { // Record this provide created on a previous pass. This can happen if the previous pass had // goog.provide('foo.bar');, but all we have now is the rewritten `foo.bar = {};`. registerAnyProvidedPrefixes(name, parent, module); ProvidedName provided = new ProvidedName(name, parent, module, true, true); providedNames.put(name, provided); provided.addDefinition(parent, module); } } /** * Verifies that a provide method call has exactly one argument, and that it's a string literal * and that the contents of the string are valid JS tokens. Reports a compile error if it doesn't. * * @return Whether the argument checked out okay */ private boolean verifyProvide(Node methodName, Node arg) { if (!verifyLastArgumentIsString(methodName, arg)) { return false; } if (!NodeUtil.isValidQualifiedName( compiler.getOptions().getLanguageIn().toFeatureSet(), arg.getString())) { compiler.report( JSError.make( arg, ProcessClosurePrimitives.INVALID_PROVIDE_ERROR, arg.getString(), compiler.getOptions().getLanguageIn().toString())); return false; } return true; } /** Marks a goog.forwardDeclare call for removal. */ private void processForwardDeclare(Node n, Node parent) { CodingConvention convention = compiler.getCodingConvention(); List typeDeclarations = convention.identifyTypeDeclarationCall(n); if (typeDeclarations != null && typeDeclarations.size() == 1) { // Forward declaration was recorded and we can remove the call. Node toRemove = parent.isExprResult() ? parent : parent.getParent(); forwardDeclaresToRemove.add(toRemove); } } /** * Verifies that a method call has exactly one argument, and that it's a string literal. Reports a * compile error if it doesn't. * * @return Whether the argument checked out okay */ private boolean verifyLastArgumentIsString(Node methodName, Node arg) { return verifyNotNull(methodName, arg) && verifyOfType(methodName, arg, Token.STRING) && verifyIsLast(methodName, arg); } /** @return Whether the argument checked out okay */ private boolean verifyNotNull(Node methodName, Node arg) { if (arg == null) { compiler.report( JSError.make( methodName, ProcessClosurePrimitives.NULL_ARGUMENT_ERROR, methodName.getQualifiedName())); return false; } return true; } /** @return Whether the argument checked out okay */ private boolean verifyOfType(Node methodName, Node arg, Token desiredType) { if (arg.getToken() != desiredType) { compiler.report( JSError.make( methodName, ProcessClosurePrimitives.INVALID_ARGUMENT_ERROR, methodName.getQualifiedName())); return false; } return true; } /** @return Whether the argument checked out okay */ private boolean verifyIsLast(Node methodName, Node arg) { if (arg.getNext() != null) { compiler.report( JSError.make( methodName, ProcessClosurePrimitives.TOO_MANY_ARGUMENTS_ERROR, methodName.getQualifiedName())); return false; } return true; } /** * Registers ProvidedNames for prefix namespaces if they haven't already been defined. The prefix * namespaces must be registered in order from shortest to longest. * * @param ns The namespace whose prefixes may need to be provided. * @param node The EXPR of the provide call. * @param module The current module. */ private void registerAnyProvidedPrefixes(String ns, Node node, JSModule module) { int pos = ns.indexOf('.'); while (pos != -1) { String prefixNs = ns.substring(0, pos); pos = ns.indexOf('.', pos + 1); if (providedNames.containsKey(prefixNs)) { providedNames.get(prefixNs).addProvide(node, module, /* explicit= */ false); } else { providedNames.put( prefixNs, new ProvidedName( prefixNs, node, module, /* explicit= */ false, /* fromPreviousProvide= */ false)); } } } // ------------------------------------------------------------------------- /** * Stores information about a Closure namespace created by a goog.provide * *

There are three ways that we find these namespaces in the AST: * *

    *
  • An explicit goog.provide. `goog.provide('a.b.c');` creates a ProvidedName for 'a.b.c'. *
  • An implicit parent namespace. `goog.provide('a.b.c');` creates a ProvidedName for 'a.b'. *
  • A provide definition processed by an earlier run. `a.b.c = {};` when annotated * IS_NAMESPACE *
*/ class ProvidedName { // The Closure namespace this name represents, e.g. `a.b` for `goog.provide('a.b');` private final String namespace; // The first node in the AST that creates this ProvidedName. // This is always a goog.provide('a.b'), null (for implicit namespaces and 'goog'), or an // assignment or declaration for a 'previously provided' name or parent namespace of such. // This should only be used for source info and a place to hang namespace definitions. private final Node firstNode; // The module where this namespace was first goog.provided, if modules exist. */ private final JSModule firstModule; // The node where the call was explicitly goog.provided. Null if the namespace is implicit. // If this is previously provided, this will instead be the expression or declaration marked // as IS_NAMESPACE. private Node explicitNode = null; // The JSModule of explicitNode, null if this is not explicit or there are no input modules. private JSModule explicitModule = null; // Whether there are child namespaces of this one. private boolean hasAChildNamespace = false; // The candidate definition for this namespace. For example, given // goog.provide('a.b'); // /** @constructor * / // a.b = function() {}; // the 'candidate definition' of 'a.b' is the GETPROP 'a.b' from the constructor declaration. private Node candidateDefinition = null; // The minimum module where the provide namespace definition must appear. If child namespaces of // this provide appear in multiple modules, this module must be earlier than all child // namespace's modules. private JSModule minimumModule = null; // The replacement declaration. Null until replace() has been called. private Node replacementNode = null; // Whether this comes not from a goog.provide, but from a leftover rewritten goog.provide from a // previous pass run. Implies this is during a hotswap pass. private final boolean isPreviouslyProvided; /** * Initializes a ProvidedName with some basic information, potentially to be updated later. * * @param node Can be null (for GOOG or an implicit name), an EXPR_RESULT for a goog.provide, or * an EXPR_RESULT or name declaration for a previously provided name. * @param explicit Whether this came from an actual goog.provide('a.b.c'); call * @param fromPreviousProvide Whether this came from a namespace created by a previous iteration */ ProvidedName( String namespace, Node node, JSModule module, boolean explicit, boolean fromPreviousProvide) { Preconditions.checkArgument( node == null || NodeUtil.isExprCall(node) || ((fromPreviousProvide || !explicit) && (NodeUtil.isExprAssign(node) || NodeUtil.isNameDeclaration(node) || node.isExprResult() && node.getFirstChild().isQualifiedName())), node); this.namespace = namespace; this.firstNode = node; this.firstModule = module; this.isPreviouslyProvided = fromPreviousProvide; addProvide(node, module, explicit); } /** * Adds an implicit or explicit provide. * *

Every provided name can have multiple implicit provides but a maximum of one explicit * provide. * *

We may also consider a namespace definition leftover from a previous pass to be a * 'provide' if in hotswap mode. * * @param node the EXPR_RESULT representing this provide or possible a VAR for a previously * provided name. null if implicit. */ void addProvide(Node node, JSModule module, boolean explicit) { if (explicit) { // goog.provide('name.space'); checkState(explicitNode == null || isPreviouslyProvided); checkArgument( node.isExprResult() || (NodeUtil.isNameDeclaration(node) && isPreviouslyProvided), node); explicitNode = node; explicitModule = module; } else { // goog.provide('name.space.some.child'); hasAChildNamespace = true; } updateMinimumModule(module); } /** Whether there existed a `goog.provide('a.b');` for this name 'a.b' */ boolean isExplicitlyProvided() { return explicitNode != null; } boolean isFromExterns() { return explicitNode.isFromExterns(); } private boolean hasCandidateDefinitionNotFromPreviousPass() { // Exclude 'candidate definitions' that were added by previous pass runs because when // rewriting provides, we can erase definitions that the compiler itself added, but not // definitions that a user added. return candidateDefinition != null && !previouslyProvidedDefinitions.contains(candidateDefinition); } /** * Returns the `goog.provide` or legacy namespace `goog.module` call that created this name, if * any, or otherwise the first 'previous provide' assignment that created this name. */ Node getFirstProvideCall() { return firstNode; } /** * Returns the definition of this provided namespace in the input code, if any, or null. * *

For example, this returns `a.b = class {};` given 'a.b' in * *

     *   goog.provide('a.b');
     *   a.b = class {};
     * 
* * Note: this method will only return candidate definitions that count towards provide * rewriting. If a name is defined, then provided, the candidate definition will not be the * early definition. This doesn't completely mimic uncompiled behavior, but supports some legacy * code. Externs definitions never count. */ Node getCandidateDefinition() { return candidateDefinition; } /** Returns the Closure namespace of this provide, e.g. "a.b" for `goog.provide('a.b');` */ String getNamespace() { return namespace; } /** * Records function declaration, variable declarations, and assignments that refer to this * provided namespace. * *

This pass gives preference to declarations. If no declaration exists, records a reference * to an assignment so it can be repurposed later into a declaration. */ private void addDefinition(Node node, JSModule module) { Preconditions.checkArgument( node.isExprResult() // assign || node.isFunction() || NodeUtil.isNameDeclaration(node)); checkArgument(explicitNode != node || isPreviouslyProvided); if ((candidateDefinition == null) || !node.isExprResult()) { candidateDefinition = node; updateMinimumModule(module); } } private void updateMinimumModule(JSModule newModule) { if (minimumModule == null) { minimumModule = newModule; } else if (moduleGraph.getModuleCount() > 1) { minimumModule = moduleGraph.getDeepestCommonDependencyInclusive(minimumModule, newModule); } else { // If there is no module graph, then there must be exactly one // module in the program. checkState(newModule == minimumModule, "Missing module graph"); } } /** * Replace the provide statement. * *

If we're providing a name with no definition, then create one. If we're providing a name * with a duplicate definition, then make sure that definition becomes a declaration. */ private void replace() { if (firstNode == null) { // Don't touch the base case ('goog'). replacementNode = candidateDefinition; return; } // Handle the case where there is a duplicate definition for an explicitly // provided symbol. if (hasCandidateDefinitionNotFromPreviousPass() && explicitNode != null) { JSDocInfo info; if (candidateDefinition.isExprResult()) { info = candidateDefinition.getFirstChild().getJSDocInfo(); } else { info = candidateDefinition.getJSDocInfo(); } // Validate that the namespace is not declared as a generic object type. if (info != null) { JSTypeExpression expr = info.getType(); if (expr != null) { Node n = expr.getRoot(); if (n.getToken() == Token.BANG) { n = n.getFirstChild(); } if (n.isString() && !n.hasChildren() // templated object types are ok. && n.getString().equals("Object")) { compiler.report( JSError.make(candidateDefinition, ProcessClosurePrimitives.WEAK_NAMESPACE_TYPE)); } } } // Does this need a VAR keyword? replacementNode = candidateDefinition; if (candidateDefinition.isExprResult()) { Node exprNode = candidateDefinition.getOnlyChild(); if (exprNode.isAssign()) { Node nameNode = exprNode.getFirstChild(); if (nameNode.isName()) { // In the case of a simple name, `name = value;`, we need to ensure the name is // actually declared with `var`. convertProvideAssignmentToVarDeclaration(exprNode, nameNode); } else { // `some.provided.namespace = value;` // We don't need to change the definition, but mark it as 'IS_NAMESPACE' so that // future passes know this was originally provided. candidateDefinition.putBooleanProp(Node.IS_NAMESPACE, true); } } else { // /** @typedef {something} */ name.space.Type; checkState(exprNode.isQualifiedName(), exprNode); // If this namespace has child namespaces, we still need to add an object to hang them // on to avoid creating broken code. // We must cast the type of the literal to unknown, because the type checker doesn't // expect the namespace to have a value. if (hasAChildNamespace) { createNamespaceInitialization( createDeclarationNode( IR.cast(IR.objectlit(), createUnknownTypeJsDocInfo(exprNode)))); } } } } else { // Handle the case where there's not an existing definition. createNamespaceInitialization(createDeclarationNode(IR.objectlit())); } // Remove the `goog.provide('a.b.c');` call. if (explicitNode != null && !isPreviouslyProvided) { if (preserveGoogProvidesAndRequires) { return; } compiler.reportChangeToEnclosingScope(explicitNode); explicitNode.detach(); } } private void convertProvideAssignmentToVarDeclaration(Node assignNode, Node nameNode) { // Convert `providedName = value;` into `var providedName = value;`. checkArgument(assignNode.isAssign(), assignNode); checkArgument(nameNode.isName(), nameNode); Node valueNode = nameNode.getNext(); assignNode.removeChild(nameNode); assignNode.removeChild(valueNode); Node varNode = IR.var(nameNode, valueNode).useSourceInfoFrom(candidateDefinition); varNode.setJSDocInfo(assignNode.getJSDocInfo()); varNode.putBooleanProp(Node.IS_NAMESPACE, true); candidateDefinition.replaceWith(varNode); replacementNode = varNode; compiler.reportChangeToEnclosingScope(varNode); } /** Adds an assignment or declaration to this namespace to the AST, using the provided value */ private void createNamespaceInitialization(Node replacement) { replacementNode = replacement; if (firstModule == minimumModule) { firstNode.getParent().addChildBefore(replacementNode, firstNode); } else { // In this case, the name was implicitly provided by two independent // modules. We need to move this code up to a common module. int indexOfDot = namespace.lastIndexOf('.'); if (indexOfDot == -1) { // Any old place is fine. compiler.getNodeForCodeInsertion(minimumModule).addChildToBack(replacementNode); } else { // Add it after the parent namespace. ProvidedName parentName = providedNames.get(namespace.substring(0, indexOfDot)); checkNotNull(parentName); checkNotNull(parentName.replacementNode); parentName .replacementNode .getParent() .addChildAfter(replacementNode, parentName.replacementNode); } } compiler.reportChangeToEnclosingScope(replacementNode); } /** * Create the declaration node for this name, without inserting it into the AST. * * @param value the object literal namespace, possibly in a CAST */ private Node createDeclarationNode(Node value) { checkArgument(value.isObjectLit() || value.isCast(), value); if (namespace.indexOf('.') == -1) { return makeVarDeclNode(value); } else { return makeAssignmentExprNode(value); } } /** Creates a simple namespace variable declaration (e.g. var foo = {};). */ private Node makeVarDeclNode(Node value) { Node name = IR.name(namespace); name.addChildToFront(value); Node decl = IR.var(name); decl.putBooleanProp(Node.IS_NAMESPACE, true); if (compiler.getCodingConvention().isConstant(namespace)) { name.putBooleanProp(Node.IS_CONSTANT_NAME, true); } if (!hasCandidateDefinitionNotFromPreviousPass()) { decl.setJSDocInfo(NodeUtil.createConstantJsDoc()); } checkState(isNamespacePlaceholder(decl)); setSourceInfo(decl); return decl; } /** Creates a dotted namespace assignment expression (e.g. foo.bar = {};). */ private Node makeAssignmentExprNode(Node value) { Node lhs = NodeUtil.newQName( compiler, namespace, firstNode /* real source info will be filled in below */, namespace); Node decl = IR.exprResult(IR.assign(lhs, value)); decl.putBooleanProp(Node.IS_NAMESPACE, true); if (!hasCandidateDefinitionNotFromPreviousPass()) { decl.getFirstChild().setJSDocInfo(NodeUtil.createConstantJsDoc()); } checkState(isNamespacePlaceholder(decl)); setSourceInfo(decl); // This function introduces artifical nodes and we don't need them for indexing. // Marking all but the last one as non-indexable. So if this function adds: // foo.bar.baz = {}; // then we mark foo and bar as non-indexable. lhs.getFirstChild().makeNonIndexableRecursive(); return decl; } /** Copy source info to the new node. */ private void setSourceInfo(Node newNode) { Node provideStringNode = getProvideStringNode(); int offset = provideStringNode == null ? 0 : getSourceInfoOffset(); Node sourceInfoNode = provideStringNode == null ? firstNode : provideStringNode; newNode.useSourceInfoIfMissingFromForTree(sourceInfoNode); if (offset != 0) { newNode.setSourceEncodedPositionForTree(sourceInfoNode.getSourcePosition() + offset); // Given namespace "foo.bar.baz" we create node for "baz" here and need to calculate // length of the last component which is "baz". int lengthOfLastComponent = namespace.length() - (namespace.lastIndexOf(".") + 1); newNode.setLengthForTree(lengthOfLastComponent); } } /** Get the offset into the provide node where the symbol appears. */ private int getSourceInfoOffset() { int indexOfLastDot = namespace.lastIndexOf('.'); // +1 for the opening quote // +1 for the dot // if there's no dot, then the -1 index cancels it out // so elegant! return 2 + indexOfLastDot; } private Node getProvideStringNode() { return (firstNode.getFirstChild() != null && NodeUtil.isExprCall(firstNode)) ? firstNode.getFirstChild().getLastChild() : null; } @Override @GwtIncompatible("Unnecessary") // This is just for debugging in an IDE. public String toString() { String explicitOrImplicit = isExplicitlyProvided() ? "explicit" : "implicit"; return String.format("ProvidedName: %s, %s", namespace, explicitOrImplicit); } } private JSDocInfo createUnknownTypeJsDocInfo(Node sourceNode) { JSDocInfoBuilder castToUnknownBuilder = new JSDocInfoBuilder(true); castToUnknownBuilder.recordType( new JSTypeExpression( new Node(Token.QMARK).srcref(sourceNode), "")); return castToUnknownBuilder.build(); } /** * Returns whether the node initializes a goog.provide'd namespace (e.g. `a.b = {};`) with a * simple namespace object literal (e.g. not `a.b = class {}`;) */ private static boolean isNamespacePlaceholder(Node n) { if (!n.getBooleanProp(Node.IS_NAMESPACE)) { return false; } Node value = null; if (n.isExprResult()) { Node assign = n.getFirstChild(); value = assign.getLastChild(); } else if (n.isVar()) { Node name = n.getFirstChild(); value = name.getFirstChild(); } if (value == null) { return false; } if (value.isCast()) { // There may be a cast to unknown type wrapped around the value. value = value.getOnlyChild(); } return value.isObjectLit() && !value.hasChildren(); } /** Add the given qualified name node to the symbol table. */ private void maybeAddStringToSymbolTable(Node string) { if (preprocessorSymbolTable != null) { preprocessorSymbolTable.addStringNode(string, compiler); } } /** Add the given qualified name node to the symbol table. */ private void maybeAddNameToSymbolTable(Node name) { if (preprocessorSymbolTable != null) { preprocessorSymbolTable.addReference(name); } } // ------------------------------------------------------------------------- /** * Information required to create a {@link ProcessClosurePrimitives#MISSING_PROVIDE_ERROR} * warning. */ private static class UnrecognizedRequire { final Node requireNode; final String namespace; final boolean isRequireType; UnrecognizedRequire(Node requireNode, String namespace, boolean isRequireType) { this.requireNode = requireNode; this.namespace = namespace; this.isRequireType = isRequireType; } } }





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