source: frontend/node_modules/webpack/lib/CodeGenerationResults.js

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

"use strict";

const { DEFAULTS } = require("./config/defaults");
const { getOrInsert } = require("./util/MapHelpers");
const { first } = require("./util/SetHelpers");
const createHash = require("./util/createHash");
const { RuntimeSpecMap, runtimeToString } = require("./util/runtime");

/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("./Module")} Module */
/** @typedef {import("./Module").SourceType} SourceType */
/** @typedef {import("./Module").CodeGenerationResult} CodeGenerationResult */
/** @typedef {import("./Module").CodeGenerationResultData} CodeGenerationResultData */
/** @typedef {import("./Module").ReadOnlyRuntimeRequirements} ReadOnlyRuntimeRequirements */
/** @typedef {import("./util/Hash").HashFunction} HashFunction */
/** @typedef {import("./util/runtime").RuntimeSpec} RuntimeSpec */

/**
 * Stores code generation results keyed by module and runtime so later stages
 * can retrieve emitted sources, metadata, and derived hashes.
 */
class CodeGenerationResults {
        /**
         * Initializes an empty result store and remembers which hash function should
         * be used when a result hash needs to be derived lazily.
         * @param {HashFunction} hashFunction the hash function to use
         */
        constructor(hashFunction = DEFAULTS.HASH_FUNCTION) {
                /** @type {Map<Module, RuntimeSpecMap<CodeGenerationResult>>} */
                this.map = new Map();
                /** @type {HashFunction} */
                this._hashFunction = hashFunction;
        }

        /**
         * Returns the code generation result for a module/runtime pair, rejecting
         * ambiguous lookups where no unique runtime-independent result exists.
         * @param {Module} module the module
         * @param {RuntimeSpec} runtime runtime(s)
         * @returns {CodeGenerationResult} the CodeGenerationResult
         */
        get(module, runtime) {
                const entry = this.map.get(module);
                if (entry === undefined) {
                        throw new Error(
                                `No code generation entry for ${module.identifier()} (existing entries: ${Array.from(
                                        this.map.keys(),
                                        (m) => m.identifier()
                                ).join(", ")})`
                        );
                }
                if (runtime === undefined) {
                        if (entry.size > 1) {
                                const results = new Set(entry.values());
                                if (results.size !== 1) {
                                        throw new Error(
                                                `No unique code generation entry for unspecified runtime for ${module.identifier()} (existing runtimes: ${Array.from(
                                                        entry.keys(),
                                                        (r) => runtimeToString(r)
                                                ).join(", ")}).
Caller might not support runtime-dependent code generation (opt-out via optimization.usedExports: "global").`
                                        );
                                }
                                return /** @type {CodeGenerationResult} */ (first(results));
                        }
                        return /** @type {CodeGenerationResult} */ (entry.values().next().value);
                }
                const result = entry.get(runtime);
                if (result === undefined) {
                        throw new Error(
                                `No code generation entry for runtime ${runtimeToString(
                                        runtime
                                )} for ${module.identifier()} (existing runtimes: ${Array.from(
                                        entry.keys(),
                                        (r) => runtimeToString(r)
                                ).join(", ")})`
                        );
                }
                return result;
        }

        /**
         * Reports whether a module has a stored result for the requested runtime, or
         * a single unambiguous result when no runtime is specified.
         * @param {Module} module the module
         * @param {RuntimeSpec} runtime runtime(s)
         * @returns {boolean} true, when we have data for this
         */
        has(module, runtime) {
                const entry = this.map.get(module);
                if (entry === undefined) {
                        return false;
                }
                if (runtime !== undefined) {
                        return entry.has(runtime);
                } else if (entry.size > 1) {
                        const results = new Set(entry.values());
                        return results.size === 1;
                }
                return entry.size === 1;
        }

        /**
         * Returns a generated source of the requested source type from a stored code
         * generation result.
         * @param {Module} module the module
         * @param {RuntimeSpec} runtime runtime(s)
         * @param {SourceType} sourceType the source type
         * @returns {Source} a source
         */
        getSource(module, runtime, sourceType) {
                return /** @type {Source} */ (
                        this.get(module, runtime).sources.get(sourceType)
                );
        }

        /**
         * Returns the runtime requirements captured during code generation for the
         * requested module/runtime pair.
         * @param {Module} module the module
         * @param {RuntimeSpec} runtime runtime(s)
         * @returns {ReadOnlyRuntimeRequirements | null} runtime requirements
         */
        getRuntimeRequirements(module, runtime) {
                return this.get(module, runtime).runtimeRequirements;
        }

        /**
         * Returns an arbitrary metadata entry recorded during code generation.
         * @param {Module} module the module
         * @param {RuntimeSpec} runtime runtime(s)
         * @param {string} key data key
         * @returns {ReturnType<CodeGenerationResultData["get"]>} data generated by code generation
         */
        getData(module, runtime, key) {
                const data = this.get(module, runtime).data;
                return data === undefined ? undefined : data.get(key);
        }

        /**
         * Returns a stable hash for the generated sources and runtime requirements,
         * computing and caching it on first access.
         * @param {Module} module the module
         * @param {RuntimeSpec} runtime runtime(s)
         * @returns {string} hash of the code generation
         */
        getHash(module, runtime) {
                const info = this.get(module, runtime);
                if (info.hash !== undefined) return info.hash;
                const hash = createHash(this._hashFunction);
                for (const [type, source] of info.sources) {
                        hash.update(type);
                        source.updateHash(hash);
                }
                if (info.runtimeRequirements) {
                        for (const rr of info.runtimeRequirements) hash.update(rr);
                }
                return (info.hash = hash.digest("hex"));
        }

        /**
         * Stores a code generation result for a module/runtime pair, creating the
         * per-module runtime map when needed.
         * @param {Module} module the module
         * @param {RuntimeSpec} runtime runtime(s)
         * @param {CodeGenerationResult} result result from module
         * @returns {void}
         */
        add(module, runtime, result) {
                const map = getOrInsert(
                        this.map,
                        module,
                        () =>
                                /** @type {RuntimeSpecMap<CodeGenerationResult>} */
                                new RuntimeSpecMap()
                );
                map.set(runtime, result);
        }
}

module.exports = CodeGenerationResults;