85 lines
No EOL
2.4 KiB
JavaScript
85 lines
No EOL
2.4 KiB
JavaScript
"use strict";
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const rename = require('./renamer');
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const t = require('@babel/types');
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const CHARSET = ('abcdefghijklmnopqrstuvwxyz' + 'ABCDEFGHIJKLMNOPQRSTUVWXYZ$_').split('');
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/**
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* This is a very specialized mangler designer to mangle only names in the top-level scope.
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* Mangling of names in other scopes happens at a file level inside workers, but we can't
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* mangle the top-level scope until scope hoisting is complete in the packager.
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*
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* Based on code from babel-minify!
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* https://github.com/babel/minify/blob/master/packages/babel-plugin-minify-mangle-names/src/charset.js
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*/
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function mangleScope(scope) {
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let newNames = new Set(); // Sort bindings so that more frequently referenced bindings get shorter names.
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let sortedBindings = Object.keys(scope.bindings).sort((a, b) => scope.bindings[b].referencePaths.length - scope.bindings[a].referencePaths.length);
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var _iteratorNormalCompletion = true;
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var _didIteratorError = false;
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var _iteratorError = undefined;
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try {
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for (var _iterator = sortedBindings[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
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let oldName = _step.value;
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let i = 0;
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let newName = '';
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do {
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newName = getIdentifier(i++);
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} while (newNames.has(newName) || !canRename(scope, scope.bindings[oldName], newName));
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rename(scope, oldName, newName);
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newNames.add(newName);
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}
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} catch (err) {
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_didIteratorError = true;
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_iteratorError = err;
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} finally {
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try {
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if (!_iteratorNormalCompletion && _iterator.return != null) {
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_iterator.return();
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}
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} finally {
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if (_didIteratorError) {
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throw _iteratorError;
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}
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}
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}
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}
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function getIdentifier(num) {
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let ret = '';
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num++;
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do {
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num--;
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ret += CHARSET[num % CHARSET.length];
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num = Math.floor(num / CHARSET.length);
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} while (num > 0);
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return ret;
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}
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function canRename(scope, binding, newName) {
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if (!t.isValidIdentifier(newName)) {
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return false;
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} // If there are any references where the parent scope has a binding
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// for the new name, we cannot rename to this name.
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for (let i = 0; i < binding.referencePaths.length; i++) {
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const ref = binding.referencePaths[i];
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if (ref.scope.hasBinding(newName) || ref.scope.hasReference(newName)) {
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return false;
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}
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}
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return true;
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}
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module.exports = mangleScope; |