dijkstra-backend-cloudron/node_modules/v8flags/index.js

163 lines
5.4 KiB
JavaScript

// this entire module is depressing. i should have spent my time learning
// how to patch v8 so that these options would just be available on the
// process object.
var os = require('os');
var fs = require('fs');
var path = require('path');
var crypto = require('crypto');
var execFile = require('child_process').execFile;
var configPath = require('./config-path.js')(process.platform);
var version = require('./package.json').version;
var env = process.env;
var user = env.LOGNAME || env.USER || env.LNAME || env.USERNAME || '';
var exclusions = ['--help'];
// This number must be incremented whenever the generated cache file changes.
var CACHE_VERSION = 1;
var configfile = '.v8flags-' + CACHE_VERSION + '-' + process.versions.v8 + '.' + crypto.createHash('md5').update(user).digest('hex') + '.json';
var failureMessage = [
'Unable to cache a config file for v8flags to your home directory',
'or a temporary folder. To fix this problem, please correct your',
'environment by setting HOME=/path/to/home or TEMP=/path/to/temp.',
'NOTE: the user running this must be able to access provided path.',
'If all else fails, please open an issue here:',
'http://github.com/tkellen/js-v8flags',
].join('\n');
function fail(err) {
err.message += '\n\n' + failureMessage;
return err;
}
function openConfig(cb) {
fs.mkdir(configPath, function() {
tryOpenConfig(path.join(configPath, configfile), function(err, fd) {
if (err) {
return tryOpenConfig(path.join(os.tmpdir(), configfile), cb);
}
return cb(null, fd);
});
});
}
function tryOpenConfig(configpath, cb) {
try {
// if the config file is valid, it should be json and therefore
// node should be able to require it directly. if this doesn't
// throw, we're done!
var content = require(configpath);
process.nextTick(function() {
cb(null, content);
});
} catch (e) {
// if requiring the config file failed, maybe it doesn't exist, or
// perhaps it has become corrupted. instead of calling back with the
// content of the file, call back with a file descriptor that we can
// write the cached data to
fs.open(configpath, 'w+', function(err, fd) {
if (err) {
return cb(err);
}
return cb(null, fd);
});
}
}
// Node <= 9 outputs _ in flags with multiple words, while node 10
// uses -. Both ways are accepted anyway, so always use `_` for better
// compatibility.
// We must not replace the first two --.
function normalizeFlagName(flag) {
return '--' + flag.slice(4).replace(/-/g, '_');
}
// i can't wait for the day this whole module is obsolete because these
// options are available on the process object. this executes node with
// `--v8-options` and parses the result, returning an array of command
// line flags.
function getFlags(cb) {
execFile(process.execPath, ['--v8-options'], function(execErr, result) {
if (execErr) {
return cb(execErr);
}
// If the binary doesn't return flags in the way we expect, default to an empty array
// Reference https://github.com/gulpjs/v8flags/issues/53
var matchedFlags = result.match(/\s\s--[\w-]+/gm) || [];
var flags = matchedFlags
.map(normalizeFlagName)
.filter(function(name) {
return exclusions.indexOf(name) === -1;
});
return cb(null, flags);
});
}
// write some json to a file descriptor. if this fails, call back
// with both the error and the data that was meant to be written.
function writeConfig(fd, flags, cb) {
var json = JSON.stringify(flags);
var buf;
if (Buffer.from && Buffer.from !== Uint8Array.from) {
// Node.js 4.5.0 or newer
buf = Buffer.from(json);
} else {
// Old Node.js versions
// The typeof safeguard below is mostly against accidental copy-pasting
// and code rewrite, it never happens as json is always a string here.
if (typeof json === 'number') {
throw new Error('Unexpected type number');
}
buf = new Buffer(json);
}
return fs.write(fd, buf, 0, buf.length, 0 , function(writeErr) {
fs.close(fd, function(closeErr) {
var err = writeErr || closeErr;
if (err) {
return cb(fail(err), flags);
}
return cb(null, flags);
});
});
}
module.exports = function(cb) {
// bail early if this is not node
var isElectron = process.versions && process.versions.electron;
if (isElectron) {
return process.nextTick(function() {
cb(null, []);
});
}
// attempt to open/read cache file
openConfig(function(openErr, result) {
if (!openErr && typeof result !== 'number') {
return cb(null, result);
}
// if the result is not an array, we need to go fetch
// the flags by invoking node with `--v8-options`
getFlags(function(flagsErr, flags) {
// if there was an error fetching the flags, bail immediately
if (flagsErr) {
return cb(flagsErr);
}
// if there was a problem opening the config file for writing
// throw an error but include the flags anyway so that users
// can continue to execute (at the expense of having to fetch
// flags on every run until they fix the underyling problem).
if (openErr) {
return cb(fail(openErr), flags);
}
// write the config file to disk so subsequent runs can read
// flags out of a cache file.
return writeConfig(result, flags, cb);
});
});
};
module.exports.configfile = configfile;
module.exports.configPath = configPath;