mirror of https://github.com/webpack/webpack.git
415 lines
13 KiB
JavaScript
415 lines
13 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const {
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harmonySpecifierTag
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} = require("../dependencies/HarmonyImportDependencyParserPlugin");
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const PureExpressionDependency = require("../dependencies/PureExpressionDependency");
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const InnerGraph = require("./InnerGraph");
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/** @typedef {import("estree").ClassDeclaration} ClassDeclarationNode */
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/** @typedef {import("estree").ClassExpression} ClassExpressionNode */
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/** @typedef {import("estree").Node} Node */
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/** @typedef {import("estree").VariableDeclarator} VariableDeclaratorNode */
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/** @typedef {import("../Compiler")} Compiler */
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/** @typedef {import("../Dependency")} Dependency */
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/** @typedef {import("../dependencies/HarmonyImportSpecifierDependency")} HarmonyImportSpecifierDependency */
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/** @typedef {import("../javascript/JavascriptParser")} JavascriptParser */
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/** @typedef {import("./InnerGraph").InnerGraph} InnerGraph */
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/** @typedef {import("./InnerGraph").TopLevelSymbol} TopLevelSymbol */
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const { topLevelSymbolTag } = InnerGraph;
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/**
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* @param {any} expr an expression
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* @param {JavascriptParser} parser the parser
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* @param {number} commentsStartPos source position from which annotation comments are checked
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* @returns {boolean} true, when the expression is pure
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*/
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const isPure = (expr, parser, commentsStartPos) => {
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switch (expr.type) {
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case "Identifier":
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return (
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parser.isVariableDefined(expr.name) ||
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parser.getTagData(expr.name, harmonySpecifierTag)
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);
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case "ClassDeclaration":
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case "ClassExpression":
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if (expr.body.type !== "ClassBody") return false;
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if (expr.superClass && !isPure(expr.superClass, parser, expr.range[0])) {
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return false;
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}
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return expr.body.body.every(item => {
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switch (item.type) {
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case "ClassProperty":
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// TODO add test case once acorn supports it
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// Currently this is not parsable
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if (item.static) return isPure(item.value, parser, item.range[0]);
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break;
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}
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return true;
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});
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case "FunctionDeclaration":
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case "FunctionExpression":
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case "ArrowFunctionExpression":
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case "Literal":
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return true;
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case "ConditionalExpression":
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return (
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isPure(expr.test, parser, commentsStartPos) &&
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isPure(expr.consequent, parser, expr.test.range[1]) &&
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isPure(expr.alternate, parser, expr.consequent.range[1])
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);
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case "SequenceExpression":
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return expr.expressions.every(expr => {
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const pureFlag = isPure(expr, parser, commentsStartPos);
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commentsStartPos = expr.range[1];
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return pureFlag;
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});
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case "CallExpression": {
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const pureFlag =
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expr.range[0] - commentsStartPos > 12 &&
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parser
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.getComments([commentsStartPos, expr.range[0]])
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.some(
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comment =>
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comment.type === "Block" &&
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/^\s*(#|@)__PURE__\s*$/.test(comment.value)
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);
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if (!pureFlag) return false;
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commentsStartPos = expr.callee.range[1];
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return expr.arguments.every(arg => {
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if (arg.type === "SpreadElement") return false;
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const pureFlag = isPure(arg, parser, commentsStartPos);
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commentsStartPos = arg.range[1];
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return pureFlag;
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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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class InnerGraphPlugin {
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/**
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* Apply the plugin
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* @param {Compiler} compiler the compiler instance
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* @returns {void}
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*/
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apply(compiler) {
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compiler.hooks.compilation.tap(
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"InnerGraphPlugin",
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(compilation, { normalModuleFactory }) => {
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const logger = compilation.getLogger("webpack.InnerGraphPlugin");
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compilation.dependencyTemplates.set(
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PureExpressionDependency,
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new PureExpressionDependency.Template()
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);
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/**
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* @param {JavascriptParser} parser the parser
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* @param {Object} parserOptions options
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* @returns {void}
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*/
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const handler = (parser, parserOptions) => {
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const onUsageSuper = sup => {
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InnerGraph.onUsage(parser.state, usedByExports => {
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switch (usedByExports) {
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case undefined:
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case true:
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return;
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default: {
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const dep = new PureExpressionDependency(sup.range);
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dep.loc = sup.loc;
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dep.usedByExports = usedByExports;
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parser.state.module.addDependency(dep);
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break;
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}
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}
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});
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};
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parser.hooks.program.tap("InnerGraphPlugin", () => {
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InnerGraph.enable(parser.state);
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});
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parser.hooks.finish.tap("InnerGraphPlugin", () => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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logger.time("infer dependency usage");
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InnerGraph.inferDependencyUsage(parser.state);
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logger.timeAggregate("infer dependency usage");
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});
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// During prewalking the following datastructures are filled with
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// nodes that have a TopLevelSymbol assigned and
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// variables are tagged with the assigned TopLevelSymbol
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// We differ 3 types of nodes:
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// 1. full statements (export default, function declaration)
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// 2. classes (class declaration, class expression)
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// 3. variable declarators (const x = ...)
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/** @type {WeakMap<Node, TopLevelSymbol>} */
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const statementWithTopLevelSymbol = new WeakMap();
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/** @type {WeakMap<Node, Node>} */
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const statementPurePart = new WeakMap();
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/** @type {WeakMap<ClassExpressionNode | ClassDeclarationNode, TopLevelSymbol>} */
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const classWithTopLevelSymbol = new WeakMap();
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/** @type {WeakMap<VariableDeclaratorNode, TopLevelSymbol>} */
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const declWithTopLevelSymbol = new WeakMap();
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/** @type {WeakSet<VariableDeclaratorNode>} */
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const pureDeclarators = new WeakSet();
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// The following hooks are used during prewalking:
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parser.hooks.preStatement.tap("InnerGraphPlugin", statement => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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if (parser.scope.topLevelScope === true) {
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if (statement.type === "FunctionDeclaration") {
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const name = statement.id ? statement.id.name : "*default*";
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const fn = InnerGraph.tagTopLevelSymbol(parser, name);
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statementWithTopLevelSymbol.set(statement, fn);
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return true;
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}
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}
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});
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parser.hooks.blockPreStatement.tap("InnerGraphPlugin", statement => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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if (parser.scope.topLevelScope === true) {
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if (statement.type === "ClassDeclaration") {
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const name = statement.id ? statement.id.name : "*default*";
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const fn = InnerGraph.tagTopLevelSymbol(parser, name);
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classWithTopLevelSymbol.set(statement, fn);
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return true;
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}
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if (statement.type === "ExportDefaultDeclaration") {
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const name = "*default*";
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const fn = InnerGraph.tagTopLevelSymbol(parser, name);
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const decl = statement.declaration;
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if (
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decl.type === "ClassExpression" ||
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decl.type === "ClassDeclaration"
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) {
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classWithTopLevelSymbol.set(decl, fn);
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} else if (isPure(decl, parser, decl.range[1])) {
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statementWithTopLevelSymbol.set(statement, fn);
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if (
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!decl.type.endsWith("FunctionExpression") &&
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!decl.type.endsWith("Declaration") &&
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decl.type !== "Literal"
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) {
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statementPurePart.set(statement, decl);
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}
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}
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}
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}
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});
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parser.hooks.preDeclarator.tap(
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"InnerGraphPlugin",
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(decl, statement) => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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if (
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parser.scope.topLevelScope === true &&
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decl.init &&
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decl.id.type === "Identifier"
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) {
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const name = decl.id.name;
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if (decl.init.type === "ClassExpression") {
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const fn = InnerGraph.tagTopLevelSymbol(parser, name);
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classWithTopLevelSymbol.set(decl.init, fn);
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} else if (isPure(decl.init, parser, decl.id.range[1])) {
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const fn = InnerGraph.tagTopLevelSymbol(parser, name);
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declWithTopLevelSymbol.set(decl, fn);
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if (
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!decl.init.type.endsWith("FunctionExpression") &&
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decl.init.type !== "Literal"
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) {
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pureDeclarators.add(decl);
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}
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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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// During real walking we set the TopLevelSymbol state to the assigned
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// TopLevelSymbol by using the fill datastructures.
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// In addition to tracking TopLevelSymbols, we sometimes need to
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// add a PureExpressionDependency. This is needed to skip execution
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// of pure expressions, even when they are not dropped due to
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// minimizing. Otherwise symbols used there might not exist anymore
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// as they are removed as unused by this optimization
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// When we find a reference to a TopLevelSymbol, we register a
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// TopLevelSymbol dependency from TopLevelSymbol in state to the
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// referenced TopLevelSymbol. This way we get a graph of all
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// TopLevelSymbols.
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// The following hooks are called during walking:
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parser.hooks.statement.tap("InnerGraphPlugin", statement => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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if (parser.scope.topLevelScope === true) {
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InnerGraph.setTopLevelSymbol(parser.state, undefined);
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const fn = statementWithTopLevelSymbol.get(statement);
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if (fn) {
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InnerGraph.setTopLevelSymbol(parser.state, fn);
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const purePart = statementPurePart.get(statement);
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if (purePart) {
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InnerGraph.onUsage(parser.state, usedByExports => {
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switch (usedByExports) {
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case undefined:
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case true:
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return;
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default: {
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const dep = new PureExpressionDependency(
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purePart.range
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);
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dep.loc = statement.loc;
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dep.usedByExports = usedByExports;
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parser.state.module.addDependency(dep);
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break;
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}
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}
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});
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}
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}
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}
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});
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parser.hooks.classExtendsExpression.tap(
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"InnerGraphPlugin",
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(expr, statement) => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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if (parser.scope.topLevelScope === true) {
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const fn = classWithTopLevelSymbol.get(statement);
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if (
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fn &&
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isPure(
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expr,
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parser,
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statement.id ? statement.id.range[1] : statement.range[0]
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)
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) {
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InnerGraph.setTopLevelSymbol(parser.state, fn);
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onUsageSuper(expr);
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}
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}
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}
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);
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parser.hooks.classBodyElement.tap(
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"InnerGraphPlugin",
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(element, statement) => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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if (parser.scope.topLevelScope === true) {
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const fn = classWithTopLevelSymbol.get(statement);
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if (fn) {
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if (element.type === "MethodDefinition") {
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InnerGraph.setTopLevelSymbol(parser.state, fn);
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} else if (
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element.type === "ClassProperty" &&
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!element.static
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) {
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// TODO add test case once acorn supports it
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// Currently this is not parsable
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InnerGraph.setTopLevelSymbol(parser.state, fn);
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} else {
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InnerGraph.setTopLevelSymbol(parser.state, undefined);
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}
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}
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}
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}
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);
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parser.hooks.declarator.tap("InnerGraphPlugin", (decl, statement) => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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const fn = declWithTopLevelSymbol.get(decl);
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if (fn) {
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InnerGraph.setTopLevelSymbol(parser.state, fn);
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if (pureDeclarators.has(decl)) {
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if (decl.init.type === "ClassExpression") {
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if (decl.init.superClass) {
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onUsageSuper(decl.init.superClass);
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}
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} else {
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InnerGraph.onUsage(parser.state, usedByExports => {
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switch (usedByExports) {
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case undefined:
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case true:
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return;
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default: {
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const dep = new PureExpressionDependency(
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decl.init.range
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);
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dep.loc = decl.loc;
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dep.usedByExports = usedByExports;
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parser.state.module.addDependency(dep);
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break;
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}
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}
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});
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}
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}
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parser.walkExpression(decl.init);
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InnerGraph.setTopLevelSymbol(parser.state, undefined);
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return true;
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}
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});
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parser.hooks.expression
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.for(topLevelSymbolTag)
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.tap("InnerGraphPlugin", () => {
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const topLevelSymbol = /** @type {TopLevelSymbol} */ (parser.currentTagData);
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const currentTopLevelSymbol = InnerGraph.getTopLevelSymbol(
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parser.state
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);
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InnerGraph.addUsage(
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parser.state,
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topLevelSymbol,
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currentTopLevelSymbol || true
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);
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});
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parser.hooks.assign
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.for(topLevelSymbolTag)
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.tap("InnerGraphPlugin", expr => {
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if (!InnerGraph.isEnabled(parser.state)) return;
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if (expr.operator === "=") return true;
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});
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};
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normalModuleFactory.hooks.parser
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.for("javascript/auto")
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.tap("InnerGraphPlugin", handler);
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normalModuleFactory.hooks.parser
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.for("javascript/esm")
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.tap("InnerGraphPlugin", handler);
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compilation.hooks.finishModules.tap("InnerGraphPlugin", () => {
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logger.timeAggregateEnd("infer dependency usage");
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});
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}
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);
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}
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}
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module.exports = InnerGraphPlugin;
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