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index.js
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index.js
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const debug = require('debug')('powerwalk')
const Duplex = require('readable-stream/duplex')
const eos = require('end-of-stream')
const errno = require('errno')
const extend = require('xtend')
const format = require('util').format
const inherits = require('inherits')
const objectType = require('./object-type')
const path = require('path')
const prr = require('prr')
const defaults = {
symlinks: false,
highWaterMark: 16,
emit: 'file',
fs: require('graceful-fs')
}
module.exports = walk
module.exports.Powerwalk = Powerwalk
function walk(dirname, options, callback) {
var length = arguments.length
for (var i = 0; i < length; i++) {
switch (typeof arguments[i]) {
case 'string':
dirname = arguments[i]
break;
case 'object':
options = arguments[i]
break;
case 'function':
callback = arguments[i]
break;
}
}
options = options || {}
options.dirname = path.resolve(dirname || '')
var stream = new Powerwalk(options)
if (callback) {
var results = []
stream.on('data', push(results))
// PowerWalk is a Duplex Stream, in the callback case we want to know when
// the stream is done writing so the results or error can be returned at
// that time.
eos(stream, { writable: false }, function endofstream(err) {
if (err) return callback(err)
else return callback(err, results)
})
}
// Start the stream if dirname is passed in.
// TODO: Do an fs.exisits to provide a non-mysterious error here.
if (dirname) {
stream.write(dirname)
}
return stream
}
function Powerwalk(options) {
if (! (this instanceof Powerwalk)) {
return new Powerwalk(options)
}
options = extend(defaults, options)
if (!(options.ignore instanceof Array)) {
options.ignore = [ options.ignore ]
}
// TODO: gaurd against invalid object types so options.emit: 'garabage'
// doesn't cause problems
// TODO: assert options.depth is a number
var powerwalk = this
Duplex.call(powerwalk, options)
prr(powerwalk, '_maxDepth', options.depth)
prr(powerwalk, '_fs', options.fs)
prr(powerwalk, '_ignore', options.ignore)
prr(powerwalk, '_emit', options.emit)
prr(powerwalk, '_symlinks', options.symlinks)
prr(powerwalk, '_queue', [])
// TODO: Use an array for the pending items.
prr(powerwalk, '_walking', {})
prr(powerwalk, '_symlinked', []);
// Keep track of symlinks since they can cause recursion cycles.
// TODO: Remove listener on end.
powerwalk.on('symlinked', push( powerwalk._symlinked))
}
inherits(Powerwalk, Duplex)
Powerwalk.prototype._read = function(size) {
var stream = this
stream.dequeue()
}
Powerwalk.prototype._write = function(buffer, encoding, callback) {
var stream = this
var pathname = buffer.toString()
// The first pathname will be treated as the _source to help with subsequent
// path resolution
if (!stream._source) {
prr(stream, '_source', pathname)
}
stream.enqueue(pathname, callback)
}
Powerwalk.prototype.enqueue = function(pathname, callback) {
callback = callback || ifError
var stream = this
stream._queue.push({
pathname: pathname,
callback: callback
})
function ifError(err) {
if (err) stream.emit('error', err)
}
}
Powerwalk.prototype.dequeue = function() {
// It's possible for the queue to be empty at this point but with pending
// async functions.
var stream = this
var entry = stream._queue.shift()
if (!entry) {
if (Object.keys(stream._walking).length === 0) {
stream.push(null)
stream.end()
}
return
}
var pathname = entry.pathname
var callback = entry.callback
stream._walking[pathname] = pathname
stream.walk(pathname, function(err, type, children) {
if (err) return callback(err)
var length = children.length
for (var i = 0; i < length; i++) {
stream.enqueue(children[i])
}
delete stream._walking[pathname]
if (!stream.symlinked(pathname)) {
stream.emit('path', pathname)
}
if (type === stream._emit) {
// If there is a successful push dequeue again, if not the stream is
// paused and dequeue will resume once the consuming stream triggers a
// call to _read.
if (stream.push(pathname)) {
stream.dequeue()
}
} else {
// Nothing to push into the pipeline, kick of another walk.
stream.dequeue()
}
callback()
})
}
Powerwalk.prototype.walk = function(pathname, callback) {
var stream = this
var children = []
// Ignore any items in the ignored array.
if (contains(stream._ignore, pathname)) {
callback(null, 'ignored', children)
return
}
var _fs = stream._fs
_fs.lstat(pathname, function(err, stats) {
if (err) return callback(error(err, 'lstat', pathname))
stream.emit('stat', pathname, stats)
var type = objectType(stats)
switch(type) {
case 'directory':
// NOTE: A relative path of "" or "foo" will both have a depth of one
// giving an incorrect depth. Adding to the depth produces correct
// results for limiting.
var relative = path.relative(stream._source, pathname)
var depth = relative.split(path.sep).length + 1
// Stop recurrion depth has been reached.
if (depth === stream._maxDepth) {
callback(null, type, children)
break
}
if (stream.symlinked(pathname)) {
debug('symlink relationship already walked')
callback(null, type, children)
break
}
_fs.readdir(pathname, function ondir(err, results) {
if (err) return callback(err)
var length = results.length
for (var i = 0; i < length; i++) {
var resolved = path.resolve(pathname, results[i])
children.push(resolved)
}
callback(null, type, children)
})
break
case 'symlink':
// On a symlink there are two properties, the original pathname and
// the resolved path of where the symlink links to (it's origin).
_fs.readlink(pathname, function onlink(err, link) {
if (err) {
return callback(error(err, 'readlink', pathname))
}
var dirname = path.dirname(pathname)
var resolved = path.resolve(dirname, link)
stream.emit('symlinked', resolved)
callback(null, type, [ resolved ])
})
break
default:
callback(null, type, children)
break
}
if (!stream.symlinked(pathname)) {
stream.emit(type, pathname)
}
})
}
Powerwalk.prototype.symlinked = function(resolved) {
return contains(this._symlinked, resolved)
}
function contains(array, item) {
return array.indexOf(item) !== -1
}
function push(array) {
return callback
function callback(buffer) {
array.push(buffer.toString())
}
}
function noop(){}
function error(err, method, pathname) {
var code = err.code || -1
var description = ''
if (errno.code[code]) {
description = errno.code[code].description
} else {
description = 'unknown error'
}
var message = format('%s "%s" failed: %s', method, pathname, description)
err.message = message
err.pathname = pathname
return err
}