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Mini Shell
Mini Shell
'use strict';
const Module = require('module');
const crypto = require('crypto');
const fs = require('fs');
const path = require('path');
const vm = require('vm');
const os = require('os');
const hasOwnProperty = Object.prototype.hasOwnProperty;
//------------------------------------------------------------------------------
// FileSystemBlobStore
//------------------------------------------------------------------------------
class FileSystemBlobStore {
constructor(directory, prefix) {
const name = prefix ? slashEscape(prefix + '.') : '';
this._blobFilename = path.join(directory, name + 'BLOB');
this._mapFilename = path.join(directory, name + 'MAP');
this._lockFilename = path.join(directory, name + 'LOCK');
this._directory = directory;
this._load();
}
has(key, invalidationKey) {
if (hasOwnProperty.call(this._memoryBlobs, key)) {
return this._invalidationKeys[key] === invalidationKey;
} else if (hasOwnProperty.call(this._storedMap, key)) {
return this._storedMap[key][0] === invalidationKey;
}
return false;
}
get(key, invalidationKey) {
if (hasOwnProperty.call(this._memoryBlobs, key)) {
if (this._invalidationKeys[key] === invalidationKey) {
return this._memoryBlobs[key];
}
} else if (hasOwnProperty.call(this._storedMap, key)) {
const mapping = this._storedMap[key];
if (mapping[0] === invalidationKey) {
return this._storedBlob.slice(mapping[1], mapping[2]);
}
}
}
set(key, invalidationKey, buffer) {
this._invalidationKeys[key] = invalidationKey;
this._memoryBlobs[key] = buffer;
this._dirty = true;
}
delete(key) {
if (hasOwnProperty.call(this._memoryBlobs, key)) {
this._dirty = true;
delete this._memoryBlobs[key];
}
if (hasOwnProperty.call(this._invalidationKeys, key)) {
this._dirty = true;
delete this._invalidationKeys[key];
}
if (hasOwnProperty.call(this._storedMap, key)) {
this._dirty = true;
delete this._storedMap[key];
}
}
isDirty() {
return this._dirty;
}
save() {
const dump = this._getDump();
const blobToStore = Buffer.concat(dump[0]);
const mapToStore = JSON.stringify(dump[1]);
try {
mkdirpSync(this._directory);
fs.writeFileSync(this._lockFilename, 'LOCK', {flag: 'wx'});
} catch (error) {
// Swallow the exception if we fail to acquire the lock.
return false;
}
try {
fs.writeFileSync(this._blobFilename, blobToStore);
fs.writeFileSync(this._mapFilename, mapToStore);
} finally {
fs.unlinkSync(this._lockFilename);
}
return true;
}
_load() {
try {
this._storedBlob = fs.readFileSync(this._blobFilename);
this._storedMap = JSON.parse(fs.readFileSync(this._mapFilename));
} catch (e) {
this._storedBlob = Buffer.alloc(0);
this._storedMap = {};
}
this._dirty = false;
this._memoryBlobs = {};
this._invalidationKeys = {};
}
_getDump() {
const buffers = [];
const newMap = {};
let offset = 0;
function push(key, invalidationKey, buffer) {
buffers.push(buffer);
newMap[key] = [invalidationKey, offset, offset + buffer.length];
offset += buffer.length;
}
for (const key of Object.keys(this._memoryBlobs)) {
const buffer = this._memoryBlobs[key];
const invalidationKey = this._invalidationKeys[key];
push(key, invalidationKey, buffer);
}
for (const key of Object.keys(this._storedMap)) {
if (hasOwnProperty.call(newMap, key)) continue;
const mapping = this._storedMap[key];
const buffer = this._storedBlob.slice(mapping[1], mapping[2]);
push(key, mapping[0], buffer);
}
return [buffers, newMap];
}
}
//------------------------------------------------------------------------------
// NativeCompileCache
//------------------------------------------------------------------------------
class NativeCompileCache {
constructor() {
this._cacheStore = null;
this._previousModuleCompile = null;
}
setCacheStore(cacheStore) {
this._cacheStore = cacheStore;
}
install() {
const self = this;
const hasRequireResolvePaths = typeof require.resolve.paths === 'function';
this._previousModuleCompile = Module.prototype._compile;
Module.prototype._compile = function(content, filename) {
const mod = this;
function require(id) {
return mod.require(id);
}
// https://github.com/nodejs/node/blob/v10.15.3/lib/internal/modules/cjs/helpers.js#L28
function resolve(request, options) {
return Module._resolveFilename(request, mod, false, options);
}
require.resolve = resolve;
// https://github.com/nodejs/node/blob/v10.15.3/lib/internal/modules/cjs/helpers.js#L37
// resolve.resolve.paths was added in v8.9.0
if (hasRequireResolvePaths) {
resolve.paths = function paths(request) {
return Module._resolveLookupPaths(request, mod, true);
};
}
require.main = process.mainModule;
// Enable support to add extra extension types
require.extensions = Module._extensions;
require.cache = Module._cache;
const dirname = path.dirname(filename);
const compiledWrapper = self._moduleCompile(filename, content);
// We skip the debugger setup because by the time we run, node has already
// done that itself.
// `Buffer` is included for Electron.
// See https://github.com/zertosh/v8-compile-cache/pull/10#issuecomment-518042543
const args = [mod.exports, require, mod, filename, dirname, process, global, Buffer];
return compiledWrapper.apply(mod.exports, args);
};
}
uninstall() {
Module.prototype._compile = this._previousModuleCompile;
}
_moduleCompile(filename, content) {
// https://github.com/nodejs/node/blob/v7.5.0/lib/module.js#L511
// Remove shebang
var contLen = content.length;
if (contLen >= 2) {
if (content.charCodeAt(0) === 35/*#*/ &&
content.charCodeAt(1) === 33/*!*/) {
if (contLen === 2) {
// Exact match
content = '';
} else {
// Find end of shebang line and slice it off
var i = 2;
for (; i < contLen; ++i) {
var code = content.charCodeAt(i);
if (code === 10/*\n*/ || code === 13/*\r*/) break;
}
if (i === contLen) {
content = '';
} else {
// Note that this actually includes the newline character(s) in the
// new output. This duplicates the behavior of the regular
// expression that was previously used to replace the shebang line
content = content.slice(i);
}
}
}
}
// create wrapper function
var wrapper = Module.wrap(content);
var invalidationKey = crypto
.createHash('sha1')
.update(content, 'utf8')
.digest('hex');
var buffer = this._cacheStore.get(filename, invalidationKey);
var script = new vm.Script(wrapper, {
filename: filename,
lineOffset: 0,
displayErrors: true,
cachedData: buffer,
produceCachedData: true,
});
if (script.cachedDataProduced) {
this._cacheStore.set(filename, invalidationKey, script.cachedData);
} else if (script.cachedDataRejected) {
this._cacheStore.delete(filename);
}
var compiledWrapper = script.runInThisContext({
filename: filename,
lineOffset: 0,
columnOffset: 0,
displayErrors: true,
});
return compiledWrapper;
}
}
//------------------------------------------------------------------------------
// utilities
//
// https://github.com/substack/node-mkdirp/blob/f2003bb/index.js#L55-L98
// https://github.com/zertosh/slash-escape/blob/e7ebb99/slash-escape.js
//------------------------------------------------------------------------------
function mkdirpSync(p_) {
_mkdirpSync(path.resolve(p_), 0o777);
}
function _mkdirpSync(p, mode) {
try {
fs.mkdirSync(p, mode);
} catch (err0) {
if (err0.code === 'ENOENT') {
_mkdirpSync(path.dirname(p));
_mkdirpSync(p);
} else {
try {
const stat = fs.statSync(p);
if (!stat.isDirectory()) { throw err0; }
} catch (err1) {
throw err0;
}
}
}
}
function slashEscape(str) {
const ESCAPE_LOOKUP = {
'\\': 'zB',
':': 'zC',
'/': 'zS',
'\x00': 'z0',
'z': 'zZ',
};
const ESCAPE_REGEX = /[\\:/\x00z]/g; // eslint-disable-line no-control-regex
return str.replace(ESCAPE_REGEX, match => ESCAPE_LOOKUP[match]);
}
function supportsCachedData() {
const script = new vm.Script('""', {produceCachedData: true});
// chakracore, as of v1.7.1.0, returns `false`.
return script.cachedDataProduced === true;
}
function getCacheDir() {
const v8_compile_cache_cache_dir = process.env.V8_COMPILE_CACHE_CACHE_DIR;
if (v8_compile_cache_cache_dir) {
return v8_compile_cache_cache_dir;
}
// Avoid cache ownership issues on POSIX systems.
const dirname = typeof process.getuid === 'function'
? 'v8-compile-cache-' + process.getuid()
: 'v8-compile-cache';
const version = typeof process.versions.v8 === 'string'
? process.versions.v8
: typeof process.versions.chakracore === 'string'
? 'chakracore-' + process.versions.chakracore
: 'node-' + process.version;
const cacheDir = path.join(os.tmpdir(), dirname, version);
return cacheDir;
}
function getMainName() {
// `require.main.filename` is undefined or null when:
// * node -e 'require("v8-compile-cache")'
// * node -r 'v8-compile-cache'
// * Or, requiring from the REPL.
const mainName = require.main && typeof require.main.filename === 'string'
? require.main.filename
: process.cwd();
return mainName;
}
//------------------------------------------------------------------------------
// main
//------------------------------------------------------------------------------
if (!process.env.DISABLE_V8_COMPILE_CACHE && supportsCachedData()) {
const cacheDir = getCacheDir();
const prefix = getMainName();
const blobStore = new FileSystemBlobStore(cacheDir, prefix);
const nativeCompileCache = new NativeCompileCache();
nativeCompileCache.setCacheStore(blobStore);
nativeCompileCache.install();
process.once('exit', () => {
if (blobStore.isDirty()) {
blobStore.save();
}
nativeCompileCache.uninstall();
});
}
module.exports.__TEST__ = {
FileSystemBlobStore,
NativeCompileCache,
mkdirpSync,
slashEscape,
supportsCachedData,
getCacheDir,
getMainName,
};
Zerion Mini Shell 1.0