722 lines
20 KiB
JavaScript
722 lines
20 KiB
JavaScript
/*
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Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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"use strict";
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/* eslint-disable no-underscore-dangle */
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/* eslint-disable no-undefined */
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const Syntax = require("estraverse").Syntax;
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const Reference = require("./reference");
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const Variable = require("./variable");
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const Definition = require("./definition").Definition;
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const assert = require("assert");
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/**
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* Test if scope is struct
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* @param {Scope} scope - scope
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* @param {Block} block - block
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* @param {boolean} isMethodDefinition - is method definiton
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* @param {boolean} useDirective - use directive
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* @returns {boolean} is strict scope
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*/
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function isStrictScope(scope, block, isMethodDefinition, useDirective) {
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let body;
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// When upper scope is exists and strict, inner scope is also strict.
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if (scope.upper && scope.upper.isStrict) {
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return true;
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}
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// ArrowFunctionExpression's scope is always strict scope.
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if (block.type === Syntax.ArrowFunctionExpression) {
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return true;
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}
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if (isMethodDefinition) {
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return true;
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}
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if (scope.type === "class" || scope.type === "module") {
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return true;
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}
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if (scope.type === "block" || scope.type === "switch") {
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return false;
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}
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if (scope.type === "function") {
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if (block.type === Syntax.Program) {
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body = block;
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} else {
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body = block.body;
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}
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if (!body) {
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return false;
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}
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} else if (scope.type === "global") {
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body = block;
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} else {
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return false;
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}
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// Search 'use strict' directive.
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if (useDirective) {
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for (let i = 0, iz = body.body.length; i < iz; ++i) {
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const stmt = body.body[i];
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if (stmt.type !== Syntax.DirectiveStatement) {
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break;
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}
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if (stmt.raw === "\"use strict\"" || stmt.raw === "'use strict'") {
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return true;
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}
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}
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} else {
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for (let i = 0, iz = body.body.length; i < iz; ++i) {
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const stmt = body.body[i];
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if (stmt.type !== Syntax.ExpressionStatement) {
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break;
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}
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const expr = stmt.expression;
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if (expr.type !== Syntax.Literal || typeof expr.value !== "string") {
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break;
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}
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if (expr.raw !== null && expr.raw !== undefined) {
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if (expr.raw === "\"use strict\"" || expr.raw === "'use strict'") {
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return true;
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}
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} else {
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if (expr.value === "use strict") {
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return true;
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}
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}
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}
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}
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return false;
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}
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/**
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* Register scope
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* @param {ScopeManager} scopeManager - scope manager
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* @param {Scope} scope - scope
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* @returns {void}
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*/
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function registerScope(scopeManager, scope) {
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scopeManager.scopes.push(scope);
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const scopes = scopeManager.__nodeToScope.get(scope.block);
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if (scopes) {
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scopes.push(scope);
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} else {
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scopeManager.__nodeToScope.set(scope.block, [scope]);
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}
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}
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/**
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* Should be statically
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* @param {Object} def - def
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* @returns {boolean} should be statically
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*/
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function shouldBeStatically(def) {
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return (
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(def.type === Variable.ClassName) ||
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(def.type === Variable.Variable && def.parent.kind !== "var")
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);
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}
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/**
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* @class Scope
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*/
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class Scope {
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constructor(scopeManager, type, upperScope, block, isMethodDefinition) {
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/**
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* One of 'TDZ', 'module', 'block', 'switch', 'function', 'catch', 'with', 'function', 'class', 'global'.
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* @member {String} Scope#type
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*/
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this.type = type;
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/**
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* The scoped {@link Variable}s of this scope, as <code>{ Variable.name
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* : Variable }</code>.
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* @member {Map} Scope#set
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*/
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this.set = new Map();
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/**
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* The tainted variables of this scope, as <code>{ Variable.name :
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* boolean }</code>.
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* @member {Map} Scope#taints */
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this.taints = new Map();
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/**
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* Generally, through the lexical scoping of JS you can always know
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* which variable an identifier in the source code refers to. There are
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* a few exceptions to this rule. With 'global' and 'with' scopes you
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* can only decide at runtime which variable a reference refers to.
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* Moreover, if 'eval()' is used in a scope, it might introduce new
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* bindings in this or its parent scopes.
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* All those scopes are considered 'dynamic'.
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* @member {boolean} Scope#dynamic
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*/
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this.dynamic = this.type === "global" || this.type === "with";
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/**
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* A reference to the scope-defining syntax node.
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* @member {espree.Node} Scope#block
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*/
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this.block = block;
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/**
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* The {@link Reference|references} that are not resolved with this scope.
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* @member {Reference[]} Scope#through
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*/
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this.through = [];
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/**
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* The scoped {@link Variable}s of this scope. In the case of a
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* 'function' scope this includes the automatic argument <em>arguments</em> as
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* its first element, as well as all further formal arguments.
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* @member {Variable[]} Scope#variables
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*/
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this.variables = [];
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/**
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* Any variable {@link Reference|reference} found in this scope. This
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* includes occurrences of local variables as well as variables from
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* parent scopes (including the global scope). For local variables
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* this also includes defining occurrences (like in a 'var' statement).
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* In a 'function' scope this does not include the occurrences of the
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* formal parameter in the parameter list.
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* @member {Reference[]} Scope#references
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*/
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this.references = [];
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/**
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* For 'global' and 'function' scopes, this is a self-reference. For
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* other scope types this is the <em>variableScope</em> value of the
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* parent scope.
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* @member {Scope} Scope#variableScope
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*/
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this.variableScope =
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(this.type === "global" || this.type === "function" || this.type === "module") ? this : upperScope.variableScope;
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/**
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* Whether this scope is created by a FunctionExpression.
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* @member {boolean} Scope#functionExpressionScope
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*/
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this.functionExpressionScope = false;
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/**
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* Whether this is a scope that contains an 'eval()' invocation.
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* @member {boolean} Scope#directCallToEvalScope
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*/
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this.directCallToEvalScope = false;
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/**
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* @member {boolean} Scope#thisFound
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*/
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this.thisFound = false;
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this.__left = [];
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/**
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* Reference to the parent {@link Scope|scope}.
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* @member {Scope} Scope#upper
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*/
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this.upper = upperScope;
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/**
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* Whether 'use strict' is in effect in this scope.
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* @member {boolean} Scope#isStrict
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*/
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this.isStrict = isStrictScope(this, block, isMethodDefinition, scopeManager.__useDirective());
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/**
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* List of nested {@link Scope}s.
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* @member {Scope[]} Scope#childScopes
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*/
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this.childScopes = [];
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if (this.upper) {
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this.upper.childScopes.push(this);
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}
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this.__declaredVariables = scopeManager.__declaredVariables;
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registerScope(scopeManager, this);
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}
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__shouldStaticallyClose(scopeManager) {
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return (!this.dynamic || scopeManager.__isOptimistic());
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}
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__shouldStaticallyCloseForGlobal(ref) {
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// On global scope, let/const/class declarations should be resolved statically.
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const name = ref.identifier.name;
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if (!this.set.has(name)) {
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return false;
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}
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const variable = this.set.get(name);
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const defs = variable.defs;
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return defs.length > 0 && defs.every(shouldBeStatically);
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}
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__staticCloseRef(ref) {
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if (!this.__resolve(ref)) {
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this.__delegateToUpperScope(ref);
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}
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}
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__dynamicCloseRef(ref) {
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// notify all names are through to global
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let current = this;
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do {
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current.through.push(ref);
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current = current.upper;
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} while (current);
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}
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__globalCloseRef(ref) {
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// let/const/class declarations should be resolved statically.
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// others should be resolved dynamically.
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if (this.__shouldStaticallyCloseForGlobal(ref)) {
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this.__staticCloseRef(ref);
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} else {
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this.__dynamicCloseRef(ref);
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}
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}
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__close(scopeManager) {
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let closeRef;
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if (this.__shouldStaticallyClose(scopeManager)) {
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closeRef = this.__staticCloseRef;
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} else if (this.type !== "global") {
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closeRef = this.__dynamicCloseRef;
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} else {
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closeRef = this.__globalCloseRef;
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}
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// Try Resolving all references in this scope.
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for (let i = 0, iz = this.__left.length; i < iz; ++i) {
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const ref = this.__left[i];
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closeRef.call(this, ref);
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}
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this.__left = null;
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return this.upper;
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}
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__resolve(ref) {
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const name = ref.identifier.name;
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if (this.set.has(name)) {
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const variable = this.set.get(name);
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variable.references.push(ref);
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variable.stack = variable.stack && ref.from.variableScope === this.variableScope;
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if (ref.tainted) {
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variable.tainted = true;
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this.taints.set(variable.name, true);
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}
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ref.resolved = variable;
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return true;
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}
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return false;
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}
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__delegateToUpperScope(ref) {
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if (this.upper) {
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this.upper.__left.push(ref);
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}
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this.through.push(ref);
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}
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__addDeclaredVariablesOfNode(variable, node) {
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if (node === null || node === undefined) {
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return;
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}
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let variables = this.__declaredVariables.get(node);
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if (variables === null || variables === undefined) {
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variables = [];
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this.__declaredVariables.set(node, variables);
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}
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if (variables.indexOf(variable) === -1) {
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variables.push(variable);
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}
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}
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__defineGeneric(name, set, variables, node, def) {
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let variable;
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variable = set.get(name);
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if (!variable) {
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variable = new Variable(name, this);
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set.set(name, variable);
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variables.push(variable);
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}
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if (def) {
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variable.defs.push(def);
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if (def.type !== Variable.TDZ) {
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this.__addDeclaredVariablesOfNode(variable, def.node);
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this.__addDeclaredVariablesOfNode(variable, def.parent);
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}
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}
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if (node) {
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variable.identifiers.push(node);
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}
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}
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__define(node, def) {
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if (node && node.type === Syntax.Identifier) {
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this.__defineGeneric(
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node.name,
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this.set,
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this.variables,
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node,
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def);
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}
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}
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__referencing(node, assign, writeExpr, maybeImplicitGlobal, partial, init) {
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// because Array element may be null
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if (!node || node.type !== Syntax.Identifier) {
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return;
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}
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// Specially handle like `this`.
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if (node.name === "super") {
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return;
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}
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const ref = new Reference(node, this, assign || Reference.READ, writeExpr, maybeImplicitGlobal, !!partial, !!init);
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this.references.push(ref);
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this.__left.push(ref);
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}
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__detectEval() {
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let current = this;
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this.directCallToEvalScope = true;
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do {
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current.dynamic = true;
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current = current.upper;
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} while (current);
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}
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__detectThis() {
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this.thisFound = true;
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}
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__isClosed() {
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return this.__left === null;
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}
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/**
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* returns resolved {Reference}
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* @method Scope#resolve
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* @param {Espree.Identifier} ident - identifier to be resolved.
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* @returns {Reference} reference
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*/
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resolve(ident) {
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let ref, i, iz;
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assert(this.__isClosed(), "Scope should be closed.");
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assert(ident.type === Syntax.Identifier, "Target should be identifier.");
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for (i = 0, iz = this.references.length; i < iz; ++i) {
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ref = this.references[i];
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if (ref.identifier === ident) {
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return ref;
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}
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}
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return null;
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}
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/**
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* returns this scope is static
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* @method Scope#isStatic
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* @returns {boolean} static
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*/
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isStatic() {
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return !this.dynamic;
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}
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/**
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* returns this scope has materialized arguments
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* @method Scope#isArgumentsMaterialized
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* @returns {boolean} arguemnts materialized
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*/
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isArgumentsMaterialized() { // eslint-disable-line class-methods-use-this
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return true;
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}
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/**
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* returns this scope has materialized `this` reference
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* @method Scope#isThisMaterialized
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* @returns {boolean} this materialized
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*/
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isThisMaterialized() { // eslint-disable-line class-methods-use-this
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return true;
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}
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isUsedName(name) {
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if (this.set.has(name)) {
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return true;
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}
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for (let i = 0, iz = this.through.length; i < iz; ++i) {
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if (this.through[i].identifier.name === name) {
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return true;
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}
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}
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return false;
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}
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}
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class GlobalScope extends Scope {
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constructor(scopeManager, block) {
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super(scopeManager, "global", null, block, false);
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this.implicit = {
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set: new Map(),
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variables: [],
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/**
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* List of {@link Reference}s that are left to be resolved (i.e. which
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* need to be linked to the variable they refer to).
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* @member {Reference[]} Scope#implicit#left
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*/
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left: []
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};
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}
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__close(scopeManager) {
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const implicit = [];
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for (let i = 0, iz = this.__left.length; i < iz; ++i) {
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const ref = this.__left[i];
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if (ref.__maybeImplicitGlobal && !this.set.has(ref.identifier.name)) {
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implicit.push(ref.__maybeImplicitGlobal);
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}
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}
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// create an implicit global variable from assignment expression
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for (let i = 0, iz = implicit.length; i < iz; ++i) {
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const info = implicit[i];
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this.__defineImplicit(info.pattern,
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new Definition(
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Variable.ImplicitGlobalVariable,
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info.pattern,
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info.node,
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null,
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null,
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null
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));
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}
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this.implicit.left = this.__left;
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return super.__close(scopeManager);
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}
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__defineImplicit(node, def) {
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if (node && node.type === Syntax.Identifier) {
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this.__defineGeneric(
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node.name,
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this.implicit.set,
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this.implicit.variables,
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node,
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def);
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}
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}
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}
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|
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class ModuleScope extends Scope {
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constructor(scopeManager, upperScope, block) {
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super(scopeManager, "module", upperScope, block, false);
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}
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}
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|
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class FunctionExpressionNameScope extends Scope {
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constructor(scopeManager, upperScope, block) {
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super(scopeManager, "function-expression-name", upperScope, block, false);
|
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this.__define(block.id,
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new Definition(
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Variable.FunctionName,
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block.id,
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block,
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null,
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null,
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null
|
|
));
|
|
this.functionExpressionScope = true;
|
|
}
|
|
}
|
|
|
|
class CatchScope extends Scope {
|
|
constructor(scopeManager, upperScope, block) {
|
|
super(scopeManager, "catch", upperScope, block, false);
|
|
}
|
|
}
|
|
|
|
class WithScope extends Scope {
|
|
constructor(scopeManager, upperScope, block) {
|
|
super(scopeManager, "with", upperScope, block, false);
|
|
}
|
|
|
|
__close(scopeManager) {
|
|
if (this.__shouldStaticallyClose(scopeManager)) {
|
|
return super.__close(scopeManager);
|
|
}
|
|
|
|
for (let i = 0, iz = this.__left.length; i < iz; ++i) {
|
|
const ref = this.__left[i];
|
|
|
|
ref.tainted = true;
|
|
this.__delegateToUpperScope(ref);
|
|
}
|
|
this.__left = null;
|
|
|
|
return this.upper;
|
|
}
|
|
}
|
|
|
|
class TDZScope extends Scope {
|
|
constructor(scopeManager, upperScope, block) {
|
|
super(scopeManager, "TDZ", upperScope, block, false);
|
|
}
|
|
}
|
|
|
|
class BlockScope extends Scope {
|
|
constructor(scopeManager, upperScope, block) {
|
|
super(scopeManager, "block", upperScope, block, false);
|
|
}
|
|
}
|
|
|
|
class SwitchScope extends Scope {
|
|
constructor(scopeManager, upperScope, block) {
|
|
super(scopeManager, "switch", upperScope, block, false);
|
|
}
|
|
}
|
|
|
|
class FunctionScope extends Scope {
|
|
constructor(scopeManager, upperScope, block, isMethodDefinition) {
|
|
super(scopeManager, "function", upperScope, block, isMethodDefinition);
|
|
|
|
// section 9.2.13, FunctionDeclarationInstantiation.
|
|
// NOTE Arrow functions never have an arguments objects.
|
|
if (this.block.type !== Syntax.ArrowFunctionExpression) {
|
|
this.__defineArguments();
|
|
}
|
|
}
|
|
|
|
isArgumentsMaterialized() {
|
|
|
|
// TODO(Constellation)
|
|
// We can more aggressive on this condition like this.
|
|
//
|
|
// function t() {
|
|
// // arguments of t is always hidden.
|
|
// function arguments() {
|
|
// }
|
|
// }
|
|
if (this.block.type === Syntax.ArrowFunctionExpression) {
|
|
return false;
|
|
}
|
|
|
|
if (!this.isStatic()) {
|
|
return true;
|
|
}
|
|
|
|
const variable = this.set.get("arguments");
|
|
|
|
assert(variable, "Always have arguments variable.");
|
|
return variable.tainted || variable.references.length !== 0;
|
|
}
|
|
|
|
isThisMaterialized() {
|
|
if (!this.isStatic()) {
|
|
return true;
|
|
}
|
|
return this.thisFound;
|
|
}
|
|
|
|
__defineArguments() {
|
|
this.__defineGeneric(
|
|
"arguments",
|
|
this.set,
|
|
this.variables,
|
|
null,
|
|
null);
|
|
this.taints.set("arguments", true);
|
|
}
|
|
}
|
|
|
|
class ForScope extends Scope {
|
|
constructor(scopeManager, upperScope, block) {
|
|
super(scopeManager, "for", upperScope, block, false);
|
|
}
|
|
}
|
|
|
|
class ClassScope extends Scope {
|
|
constructor(scopeManager, upperScope, block) {
|
|
super(scopeManager, "class", upperScope, block, false);
|
|
}
|
|
}
|
|
|
|
module.exports = {
|
|
Scope,
|
|
GlobalScope,
|
|
ModuleScope,
|
|
FunctionExpressionNameScope,
|
|
CatchScope,
|
|
WithScope,
|
|
TDZScope,
|
|
BlockScope,
|
|
SwitchScope,
|
|
FunctionScope,
|
|
ForScope,
|
|
ClassScope
|
|
};
|
|
|
|
/* vim: set sw=4 ts=4 et tw=80 : */
|