webpack/lib/FlagDependencyUsagePlugin.js

122 lines
3.3 KiB
JavaScript

/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const { STAGE_DEFAULT } = require("./OptimizationStages");
const Queue = require("./util/Queue");
/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./DependenciesBlock")} DependenciesBlock */
/** @typedef {import("./Dependency")} Dependency */
/** @typedef {import("./Module")} Module */
class FlagDependencyUsagePlugin {
/**
* @param {Compiler} compiler the compiler instance
* @returns {void}
*/
apply(compiler) {
compiler.hooks.compilation.tap("FlagDependencyUsagePlugin", compilation => {
const moduleGraph = compilation.moduleGraph;
compilation.hooks.optimizeDependencies.tap(
{
name: "FlagDependencyUsagePlugin",
stage: STAGE_DEFAULT
},
modules => {
/**
*
* @param {Module} module module to process
* @param {boolean | string[]} usedExports list of used exports
* @returns {void}
*/
const processModule = (module, usedExports) => {
const exportsInfo = moduleGraph.getExportsInfo(module);
let changed = false;
if (usedExports === true) {
changed = exportsInfo.setUsedInUnknownWay();
} else if (usedExports) {
for (const exportName of usedExports) {
if (
exportName === "default" &&
module.buildMeta.exportsType === "named"
) {
if (exportsInfo.setUsedAsNamedExportType()) {
changed = true;
}
} else {
const exportInfo = exportsInfo.getExportInfo(exportName);
if (exportInfo.used !== true) {
exportInfo.used = true;
changed = true;
}
}
}
} else {
// 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) return;
changed = exportsInfo.setUsedForSideEffectsOnly();
}
if (changed) {
queue.enqueue(module);
}
};
/**
* @param {DependenciesBlock} depBlock the dependencies block
* @returns {void}
*/
const processDependenciesBlock = depBlock => {
for (const dep of depBlock.dependencies) {
processDependency(dep);
}
for (const block of depBlock.blocks) {
queue.enqueue(block);
}
};
/**
* @param {Dependency} dep the dependency
* @returns {void}
*/
const processDependency = dep => {
const reference = compilation.getDependencyReference(dep);
if (!reference) return;
const referenceModule = reference.module;
const importedNames = reference.importedNames;
processModule(referenceModule, importedNames);
};
for (const module of modules) {
moduleGraph.getExportsInfo(module).setHasUseInfo();
}
/** @type {Queue<DependenciesBlock>} */
const queue = new Queue();
for (const deps of compilation.entryDependencies.values()) {
for (const dep of deps) {
const module = moduleGraph.getModule(dep);
if (module) {
processModule(module, true);
}
}
}
while (queue.length) {
const depBlock = queue.dequeue();
processDependenciesBlock(depBlock);
}
}
);
});
}
}
module.exports = FlagDependencyUsagePlugin;