webpack/lib/ResolverFactory.js

/*
 MIT License http://www.opensource.org/licenses/mit-license.php
 Author Tobias Koppers @sokra
 */
"use strict";

const Tapable = require("tapable").Tapable;
const HookMap = require("tapable").HookMap;
const SyncHook = require("tapable").SyncHook;
const SyncWaterfallHook = require("tapable").SyncWaterfallHook;
const Factory = require("enhanced-resolve").ResolverFactory;

module.exports = class ResolverFactory extends Tapable {
	constructor() {
		super();
		this.hooks = {
			resolveOptions: new HookMap(() => new SyncWaterfallHook(["resolveOptions"])),
			resolver: new HookMap(() => new SyncHook(["resolver", "resolveOptions"])),
		};
		this._pluginCompat.tap("ResolverFactory", options => {
			let match;
			match = /^resolve-options (.+)$/.exec(options.name);
			if(match) {
				this.hooks.resolveOptions.tap(match[1], options.fn.name || "unnamed compat plugin", options.fn);
				return true;
			}
			match = /^resolver (.+)$/.exec(options.name);
			if(match) {
				this.hooks.resolver.tap(match[1], options.fn.name || "unnamed compat plugin", options.fn);
				return true;
			}
		});
		this.cache1 = new WeakMap();
		this.cache2 = new Map();
	}

	get(type, resolveOptions) {
		const cachedResolver = this.cache1.get(resolveOptions);
		if(cachedResolver) return cachedResolver();
		const ident = `${type}|${JSON.stringify(resolveOptions)}`;
		const resolver = this.cache2.get(ident);
		if(resolver) return resolver;
		const newResolver = this._create(type, resolveOptions);
		this.cache2.set(ident, newResolver);
		return newResolver;
	}

	_create(type, resolveOptions) {
		resolveOptions = this.hooks.resolveOptions.for(type).call(resolveOptions);
		const resolver = Factory.createResolver(resolveOptions);
		if(!resolver) {
			throw new Error("No resolver created");
		}
		this.hooks.resolver.for(type).call(resolver, resolveOptions);
		return resolver;
	}
};