webpack/lib/DependenciesBlock.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

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

"use strict";

const makeSerializable = require("./util/makeSerializable");

/** @typedef {import("./AsyncDependenciesBlock")} AsyncDependenciesBlock */
/** @typedef {import("./Dependency")} Dependency */
/** @typedef {import("./Dependency").UpdateHashContext} UpdateHashContext */
/** @typedef {import("./serialization/ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
/** @typedef {import("./serialization/ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
/** @typedef {import("./util/Hash")} Hash */

/** @typedef {(d: Dependency) => boolean} DependencyFilterFunction */

/**
 * DependenciesBlock is the base class for all Module classes in webpack. It describes a
 * "block" of dependencies which are pointers to other DependenciesBlock instances. For example
 * when a Module has a CommonJs require statement, the DependencyBlock for the CommonJs module
 * would be added as a dependency to the Module. DependenciesBlock is inherited by two types of classes:
 * Module subclasses and AsyncDependenciesBlock subclasses. The only difference between the two is that
 * AsyncDependenciesBlock subclasses are used for code-splitting (async boundary) and Module subclasses are not.
 */
class DependenciesBlock {
	constructor() {
		/** @type {Dependency[]} */
		this.dependencies = [];
		/** @type {AsyncDependenciesBlock[]} */
		this.blocks = [];
		/** @type {DependenciesBlock | undefined} */
		this.parent = undefined;
	}

	getRootBlock() {
		/** @type {DependenciesBlock} */
		let current = this;
		while (current.parent) current = current.parent;
		return current;
	}

	/**
	 * Adds a DependencyBlock to DependencyBlock relationship.
	 * This is used for when a Module has a AsyncDependencyBlock tie (for code-splitting)
	 * @param {AsyncDependenciesBlock} block block being added
	 * @returns {void}
	 */
	addBlock(block) {
		this.blocks.push(block);
		block.parent = this;
	}

	/**
	 * Adds the provided dependency to the dependencies block.
	 * @param {Dependency} dependency dependency being tied to block.
	 * This is an "edge" pointing to another "node" on module graph.
	 * @returns {void}
	 */
	addDependency(dependency) {
		this.dependencies.push(dependency);
	}

	/**
	 * Removes dependency.
	 * @param {Dependency} dependency dependency being removed
	 * @returns {void}
	 */
	removeDependency(dependency) {
		const idx = this.dependencies.indexOf(dependency);
		if (idx >= 0) {
			this.dependencies.splice(idx, 1);
		}
	}

	/**
	 * Clear dependencies and blocks.
	 * @returns {void}
	 */
	clearDependenciesAndBlocks() {
		this.dependencies.length = 0;
		this.blocks.length = 0;
	}

	/**
	 * Updates the hash with the data contributed by this instance.
	 * @param {Hash} hash the hash used to track dependencies
	 * @param {UpdateHashContext} context context
	 * @returns {void}
	 */
	updateHash(hash, context) {
		for (const dep of this.dependencies) {
			dep.updateHash(hash, context);
		}
		for (const block of this.blocks) {
			block.updateHash(hash, context);
		}
	}

	/**
	 * Serializes this instance into the provided serializer context.
	 * @param {ObjectSerializerContext} context context
	 */
	serialize({ write }) {
		write(this.dependencies);
		write(this.blocks);
	}

	/**
	 * Restores this instance from the provided deserializer context.
	 * @param {ObjectDeserializerContext} context context
	 */
	deserialize({ read }) {
		this.dependencies = read();
		this.blocks = read();
		for (const block of this.blocks) {
			block.parent = this;
		}
	}
}

makeSerializable(DependenciesBlock, "webpack/lib/DependenciesBlock");

module.exports = DependenciesBlock;