mirror of https://github.com/webpack/webpack.git
82 lines
2.3 KiB
JavaScript
82 lines
2.3 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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class FlagDependencyUsagePlugin {
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apply(compiler) {
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compiler.plugin("compilation", compilation => {
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compilation.plugin("optimize-modules-advanced", modules => {
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modules.forEach(module => module.used = false);
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const queue = [];
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compilation.chunks.forEach(chunk => {
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if(chunk.entryModule) {
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processModule(chunk.entryModule, true);
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}
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});
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while(queue.length) {
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const queueItem = queue.pop();
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processDependenciesBlock(queueItem[0], queueItem[1]);
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}
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function processModule(module, usedExports) {
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module.used = true;
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if(module.usedExports === true)
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return;
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else if(usedExports === true)
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module.usedExports = true;
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else if(Array.isArray(usedExports)) {
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const old = module.usedExports ? module.usedExports.length : -1;
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module.usedExports = addToSet(module.usedExports || [], usedExports);
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if(module.usedExports.length === old)
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return;
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} else if(Array.isArray(module.usedExports))
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return;
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else
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module.usedExports = false;
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queue.push([module, module.usedExports]);
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}
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function processDependenciesBlock(depBlock, usedExports) {
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depBlock.dependencies.forEach(dep => processDependency(dep));
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depBlock.variables.forEach(variable => variable.dependencies.forEach(dep => processDependency(dep)));
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depBlock.blocks.forEach(block => queue.push([block, usedExports]));
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}
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function processDependency(dep) {
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const reference = dep.getReference && dep.getReference();
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if(!reference) return;
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const module = reference.module;
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const importedNames = reference.importedNames;
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const oldUsed = module.used;
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const oldUsedExports = module.usedExports;
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if(!oldUsed || (importedNames && (!oldUsedExports || !isSubset(oldUsedExports, importedNames)))) {
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processModule(module, importedNames);
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}
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}
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});
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function addToSet(a, b) {
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b.forEach(item => {
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if(a.indexOf(item) < 0)
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a.push(item);
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});
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return a;
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}
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function isSubset(biggerSet, subset) {
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if(biggerSet === true) return true;
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if(subset === true) return false;
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return subset.every(item => biggerSet.indexOf(item) >= 0);
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}
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});
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}
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}
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module.exports = FlagDependencyUsagePlugin;
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