ok
Mini Shell
var fs = require('fs')
var wx = 'wx'
if (process.version.match(/^v0\.[0-6]/)) {
var c = require('constants')
wx = c.O_TRUNC | c.O_CREAT | c.O_WRONLY | c.O_EXCL
}
var os = require('os')
exports.filetime = 'ctime'
if (os.platform() == "win32") {
exports.filetime = 'mtime'
}
var debug
var util = require('util')
if (util.debuglog)
debug = util.debuglog('LOCKFILE')
else if (/\blockfile\b/i.test(process.env.NODE_DEBUG))
debug = function() {
var msg = util.format.apply(util, arguments)
console.error('LOCKFILE %d %s', process.pid, msg)
}
else
debug = function() {}
var locks = {}
function hasOwnProperty (obj, prop) {
return Object.prototype.hasOwnProperty.call(obj, prop)
}
var onExit = require('signal-exit')
onExit(function () {
debug('exit listener')
// cleanup
Object.keys(locks).forEach(exports.unlockSync)
})
// XXX https://github.com/joyent/node/issues/3555
// Remove when node 0.8 is deprecated.
if (/^v0\.[0-8]\./.test(process.version)) {
debug('uncaughtException, version = %s', process.version)
process.on('uncaughtException', function H (er) {
debug('uncaughtException')
var l = process.listeners('uncaughtException').filter(function (h) {
return h !== H
})
if (!l.length) {
// cleanup
try { Object.keys(locks).forEach(exports.unlockSync) } catch (e) {}
process.removeListener('uncaughtException', H)
throw er
}
})
}
exports.unlock = function (path, cb) {
debug('unlock', path)
// best-effort. unlocking an already-unlocked lock is a noop
delete locks[path]
fs.unlink(path, function (unlinkEr) { cb && cb() })
}
exports.unlockSync = function (path) {
debug('unlockSync', path)
// best-effort. unlocking an already-unlocked lock is a noop
try { fs.unlinkSync(path) } catch (er) {}
delete locks[path]
}
// if the file can be opened in readonly mode, then it's there.
// if the error is something other than ENOENT, then it's not.
exports.check = function (path, opts, cb) {
if (typeof opts === 'function') cb = opts, opts = {}
debug('check', path, opts)
fs.open(path, 'r', function (er, fd) {
if (er) {
if (er.code !== 'ENOENT') return cb(er)
return cb(null, false)
}
if (!opts.stale) {
return fs.close(fd, function (er) {
return cb(er, true)
})
}
fs.fstat(fd, function (er, st) {
if (er) return fs.close(fd, function (er2) {
return cb(er)
})
fs.close(fd, function (er) {
var age = Date.now() - st[exports.filetime].getTime()
return cb(er, age <= opts.stale)
})
})
})
}
exports.checkSync = function (path, opts) {
opts = opts || {}
debug('checkSync', path, opts)
if (opts.wait) {
throw new Error('opts.wait not supported sync for obvious reasons')
}
try {
var fd = fs.openSync(path, 'r')
} catch (er) {
if (er.code !== 'ENOENT') throw er
return false
}
if (!opts.stale) {
try { fs.closeSync(fd) } catch (er) {}
return true
}
// file exists. however, might be stale
if (opts.stale) {
try {
var st = fs.fstatSync(fd)
} finally {
fs.closeSync(fd)
}
var age = Date.now() - st[exports.filetime].getTime()
return (age <= opts.stale)
}
}
var req = 1
exports.lock = function (path, opts, cb) {
if (typeof opts === 'function') cb = opts, opts = {}
opts.req = opts.req || req++
debug('lock', path, opts)
opts.start = opts.start || Date.now()
if (typeof opts.retries === 'number' && opts.retries > 0) {
debug('has retries', opts.retries)
var retries = opts.retries
opts.retries = 0
cb = (function (orig) { return function cb (er, fd) {
debug('retry-mutated callback')
retries -= 1
if (!er || retries < 0) return orig(er, fd)
debug('lock retry', path, opts)
if (opts.retryWait) setTimeout(retry, opts.retryWait)
else retry()
function retry () {
opts.start = Date.now()
debug('retrying', opts.start)
exports.lock(path, opts, cb)
}
}})(cb)
}
// try to engage the lock.
// if this succeeds, then we're in business.
fs.open(path, wx, function (er, fd) {
if (!er) {
debug('locked', path, fd)
locks[path] = fd
return fs.close(fd, function () {
return cb()
})
}
debug('failed to acquire lock', er)
// something other than "currently locked"
// maybe eperm or something.
if (er.code !== 'EEXIST') {
debug('not EEXIST error', er)
return cb(er)
}
// someone's got this one. see if it's valid.
if (!opts.stale) return notStale(er, path, opts, cb)
return maybeStale(er, path, opts, false, cb)
})
debug('lock return')
}
// Staleness checking algorithm
// 1. acquire $lock, fail
// 2. stat $lock, find that it is stale
// 3. acquire $lock.STALE
// 4. stat $lock, assert that it is still stale
// 5. unlink $lock
// 6. link $lock.STALE $lock
// 7. unlink $lock.STALE
// On any failure, clean up whatever we've done, and raise the error.
function maybeStale (originalEr, path, opts, hasStaleLock, cb) {
fs.stat(path, function (statEr, st) {
if (statEr) {
if (statEr.code === 'ENOENT') {
// expired already!
opts.stale = false
debug('lock stale enoent retry', path, opts)
exports.lock(path, opts, cb)
return
}
return cb(statEr)
}
var age = Date.now() - st[exports.filetime].getTime()
if (age <= opts.stale) return notStale(originalEr, path, opts, cb)
debug('lock stale', path, opts)
if (hasStaleLock) {
exports.unlock(path, function (er) {
if (er) return cb(er)
debug('lock stale retry', path, opts)
fs.link(path + '.STALE', path, function (er) {
fs.unlink(path + '.STALE', function () {
// best effort. if the unlink fails, oh well.
cb(er)
})
})
})
} else {
debug('acquire .STALE file lock', opts)
exports.lock(path + '.STALE', opts, function (er) {
if (er) return cb(er)
maybeStale(originalEr, path, opts, true, cb)
})
}
})
}
function notStale (er, path, opts, cb) {
debug('notStale', path, opts)
// if we can't wait, then just call it a failure
if (typeof opts.wait !== 'number' || opts.wait <= 0) {
debug('notStale, wait is not a number')
return cb(er)
}
// poll for some ms for the lock to clear
var now = Date.now()
var start = opts.start || now
var end = start + opts.wait
if (end <= now)
return cb(er)
debug('now=%d, wait until %d (delta=%d)', start, end, end-start)
var wait = Math.min(end - start, opts.pollPeriod || 100)
var timer = setTimeout(poll, wait)
function poll () {
debug('notStale, polling', path, opts)
exports.lock(path, opts, cb)
}
}
exports.lockSync = function (path, opts) {
opts = opts || {}
opts.req = opts.req || req++
debug('lockSync', path, opts)
if (opts.wait || opts.retryWait) {
throw new Error('opts.wait not supported sync for obvious reasons')
}
try {
var fd = fs.openSync(path, wx)
locks[path] = fd
try { fs.closeSync(fd) } catch (er) {}
debug('locked sync!', path, fd)
return
} catch (er) {
if (er.code !== 'EEXIST') return retryThrow(path, opts, er)
if (opts.stale) {
var st = fs.statSync(path)
var ct = st[exports.filetime].getTime()
if (!(ct % 1000) && (opts.stale % 1000)) {
// probably don't have subsecond resolution.
// round up the staleness indicator.
// Yes, this will be wrong 1/1000 times on platforms
// with subsecond stat precision, but that's acceptable
// in exchange for not mistakenly removing locks on
// most other systems.
opts.stale = 1000 * Math.ceil(opts.stale / 1000)
}
var age = Date.now() - ct
if (age > opts.stale) {
debug('lockSync stale', path, opts, age)
exports.unlockSync(path)
return exports.lockSync(path, opts)
}
}
// failed to lock!
debug('failed to lock', path, opts, er)
return retryThrow(path, opts, er)
}
}
function retryThrow (path, opts, er) {
if (typeof opts.retries === 'number' && opts.retries > 0) {
var newRT = opts.retries - 1
debug('retryThrow', path, opts, newRT)
opts.retries = newRT
return exports.lockSync(path, opts)
}
throw er
}
Zerion Mini Shell 1.0