text: /*
  	MIT License http://www.opensource.org/licenses/mit-license.php
  	Author Tobias Koppers @sokra
  */
  "use strict";
  
  const addToSet = (a, b) => {
  	for (const item of b) {
  		if (!a.includes(item)) a.push(item);
  	}
  	return a;
  };
  
  const isSubset = (biggerSet, subset) => {
  	if (biggerSet === true) return true;
  	if (subset === true) return false;
  	return subset.every(item => biggerSet.indexOf(item) >= 0);
  };
  
  class FlagDependencyUsagePlugin {
  	apply(compiler) {
  		compiler.hooks.compilation.tap("FlagDependencyUsagePlugin", compilation => {
  			compilation.hooks.optimizeDependencies.tap(
  				"FlagDependencyUsagePlugin",
  				modules => {
  					const processModule = (module, usedExports) => {
  						module.used = true;
  						if (module.usedExports === true) return;
  						if (usedExports === true) {
  							module.usedExports = true;
  						} else if (Array.isArray(usedExports)) {
  							const old = module.usedExports ? module.usedExports.length : -1;
  							module.usedExports = addToSet(
  								module.usedExports || [],
  								usedExports
  							);
  							if (module.usedExports.length === old) {
  								return;
  							}
  						} else if (Array.isArray(module.usedExports)) {
  							return;
  						} else {
  							module.usedExports = false;
  						}
  
  						// for a module without side effects we stop tracking usage here when no export is used
  						// This module won't be evaluated in this case
  						if (module.factoryMeta.sideEffectFree) {
  							if (module.usedExports === false) return;
  							if (
  								Array.isArray(module.usedExports) &&
  								module.usedExports.length === 0
  							)
  								return;
  						}
  
  						queue.push([module, module.usedExports]);
  					};
  
  					const processDependenciesBlock = (depBlock, usedExports) => {
  						for (const dep of depBlock.dependencies) {
  							processDependency(dep);
  						}
  						for (const variable of depBlock.variables) {
  							for (const dep of variable.dependencies) {
  								processDependency(dep);
  							}
  						}
  						for (const block of depBlock.blocks) {
  							queue.push([block, usedExports]);
  						}
  					};
  
  					const processDependency = dep => {
  						// TODO remove dep.getReference existance check in webpack 5
  						const reference = dep.getReference && dep.getReference();
  						if (!reference) return;
  						const module = reference.module;
  						const importedNames = reference.importedNames;
  						const oldUsed = module.used;
  						const oldUsedExports = module.usedExports;
  						if (
  							!oldUsed ||
  							(importedNames &&
  								(!oldUsedExports || !isSubset(oldUsedExports, importedNames)))
  						) {
  							processModule(module, importedNames);
  						}
  					};
  
  					for (const module of modules) {
  						module.used = false;
  					}
  
  					const queue = [];
  					for (const preparedEntrypoint of compilation._preparedEntrypoints) {
  						if (preparedEntrypoint.module) {
  							processModule(preparedEntrypoint.module, true);
  						}
  					}
  
  					while (queue.length) {
  						const queueItem = queue.pop();
  						processDependenciesBlock(queueItem[0], queueItem[1]);
  					}
  				}
  			);
  		});
  	}
  }
  module.exports = FlagDependencyUsagePlugin;
  