mirror of https://github.com/webpack/webpack.git
				
				
				
			
		
			
				
	
	
		
			369 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
			
		
		
	
	
			369 lines
		
	
	
		
			12 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 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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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 (parser.isPure(decl, statement.range[0])) {
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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 (parser.isPure(decl.init, 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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									parser.isPure(
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										expr,
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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, classDefinition) => {
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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(classDefinition);
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								if (fn) {
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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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					parser.hooks.classBodyValue.tap(
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						"InnerGraphPlugin",
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						(expression, element, classDefinition) => {
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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(classDefinition);
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								if (fn) {
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									if (
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										!element.static ||
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										parser.isPure(
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											expression,
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											element.key ? element.key.range[1] : element.range[0]
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										)
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									) {
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										InnerGraph.setTopLevelSymbol(parser.state, fn);
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										if (element.type !== "MethodDefinition" && element.static) {
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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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															expression.range
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														);
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														dep.loc = expression.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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									} 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} */ (
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								parser.currentTagData
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							);
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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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