var pathModule = require('path'); 
var isWindows = process.platform === 'win32'; 
var fs = require('fs'); 
var DEBUG = process.env.NODE_DEBUG && /fs/.test(process.env.NODE_DEBUG); 
function rethrow(){ 
var callback; 
if (DEBUG) { 
var backtrace = new Error(); 
callback = debugCallback; 
} 
 else callback = missingCallback; 
return callback; 
function debugCallback(err){ 
if (err) { 
backtrace.message = err.message; 
err = backtrace; 
missingCallback(err); 
} 
} 
function missingCallback(err){ 
if (err) { 
if (process.throwDeprecation) throw err
 else if (!process.noDeprecation) { 
var msg = 'fs: missing callback ' + (err.stack || err.message); 
if (process.traceDeprecation) console.trace(msg); 
 else console.error(msg); 
} 
} 
} 
} 
function maybeCallback(cb){ 
return typeof cb === 'function'? cb: rethrow(); 
} 
var normalize = pathModule.normalize; 
if (isWindows) { 
var nextPartRe = /(.*?)(?:[\/\\]+|$)/g; 
} 
 else { 
var nextPartRe = /(.*?)(?:[\/]+|$)/g; 
} 
if (isWindows) { 
var splitRootRe = /^(?:[a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/][^\\\/]+)?[\\\/]*/; 
} 
 else { 
var splitRootRe = /^[\/]*/; 
} 
exports.realpathSync = function realpathSync(p, cache){ 
p = pathModule.resolve(p); 
if (cache && Object.prototype.hasOwnProperty.call(cache, p)) { 
return cache[p]; 
} 
var original = p, seenLinks = { 
}
, knownHard = { 
}
; 
var pos; 
var current; 
var base; 
var previous; 
start(); 
function start(){ 
var m = splitRootRe.exec(p); 
pos = _AN_Read_length('length', m[0]); 
current = m[0]; 
base = m[0]; 
previous = ''; 
if (isWindows && !knownHard[base]) { 
fs.lstatSync(base); 
knownHard[base] = true ; 
} 
} 
while (pos < _AN_Read_length('length', p)){ 
nextPartRe.lastIndex = pos; 
var result = nextPartRe.exec(p); 
previous = current; 
current += result[0]; 
base = previous + result[1]; 
pos = nextPartRe.lastIndex; 
if (knownHard[base] || (cache && cache[base] === base)) { 
continue ; 
} 
var resolvedLink; 
if (cache && Object.prototype.hasOwnProperty.call(cache, base)) { 
resolvedLink = cache[base]; 
} 
 else { 
var stat = fs.lstatSync(base); 
if (!stat.isSymbolicLink()) { 
knownHard[base] = true ; 
if (cache) cache[base] = base; 
continue ; 
} 
var linkTarget = null ; 
if (!isWindows) { 
var id = stat.dev.toString(32) + ':' + stat.ino.toString(32); 
if (seenLinks.hasOwnProperty(id)) { 
linkTarget = seenLinks[id]; 
} 
} 
if (linkTarget === null ) { 
fs.statSync(base); 
linkTarget = fs.readlinkSync(base); 
} 
resolvedLink = pathModule.resolve(previous, linkTarget); 
if (cache) cache[base] = resolvedLink; 
if (!isWindows) seenLinks[id] = linkTarget; 
} 
p = pathModule.resolve(resolvedLink, p.slice(pos)); 
start(); 
} 
if (cache) cache[original] = p; 
return p; 
} 
; 
exports.realpath = function realpath(p, cache, cb){ 
if (typeof cb !== 'function') { 
cb = maybeCallback(cache); 
cache = null ; 
} 
p = pathModule.resolve(p); 
if (cache && Object.prototype.hasOwnProperty.call(cache, p)) { 
return process.nextTick(cb.bind(null , null , cache[p])); 
} 
var original = p, seenLinks = { 
}
, knownHard = { 
}
; 
var pos; 
var current; 
var base; 
var previous; 
start(); 
function start(){ 
var m = splitRootRe.exec(p); 
pos = _AN_Read_length('length', m[0]); 
current = m[0]; 
base = m[0]; 
previous = ''; 
if (isWindows && !knownHard[base]) { 
fs.lstat(base, function (err){ 
if (err) return cb(err); 
knownHard[base] = true ; 
LOOP(); 
} 
); 
} 
 else { 
process.nextTick(LOOP); 
} 
} 
function LOOP(){ 
if (pos >= _AN_Read_length('length', p)) { 
if (cache) cache[original] = p; 
return cb(null , p); 
} 
nextPartRe.lastIndex = pos; 
var result = nextPartRe.exec(p); 
previous = current; 
current += result[0]; 
base = previous + result[1]; 
pos = nextPartRe.lastIndex; 
if (knownHard[base] || (cache && cache[base] === base)) { 
return process.nextTick(LOOP); 
} 
if (cache && Object.prototype.hasOwnProperty.call(cache, base)) { 
return gotResolvedLink(cache[base]); 
} 
return fs.lstat(base, gotStat); 
} 
function gotStat(err, stat){ 
if (err) return cb(err); 
if (!stat.isSymbolicLink()) { 
knownHard[base] = true ; 
if (cache) cache[base] = base; 
return process.nextTick(LOOP); 
} 
if (!isWindows) { 
var id = stat.dev.toString(32) + ':' + stat.ino.toString(32); 
if (seenLinks.hasOwnProperty(id)) { 
return gotTarget(null , seenLinks[id], base); 
} 
} 
fs.stat(base, function (err){ 
if (err) return cb(err); 
fs.readlink(base, function (err, target){ 
if (!isWindows) seenLinks[id] = target; 
gotTarget(err, target); 
} 
); 
} 
); 
} 
function gotTarget(err, target, base){ 
if (err) return cb(err); 
var resolvedLink = pathModule.resolve(previous, target); 
if (cache) cache[base] = resolvedLink; 
gotResolvedLink(resolvedLink); 
} 
function gotResolvedLink(resolvedLink){ 
p = pathModule.resolve(resolvedLink, p.slice(pos)); 
start(); 
} 
} 
;