tra-analysis/website/functions/node_modules/@mrmlnc/readdir-enhanced/lib/directory-reader.js
2019-01-06 13:14:45 -06:00

381 lines
12 KiB
JavaScript

'use strict';
const Readable = require('stream').Readable;
const EventEmitter = require('events').EventEmitter;
const path = require('path');
const normalizeOptions = require('./normalize-options');
const stat = require('./stat');
const call = require('./call');
/**
* Asynchronously reads the contents of a directory and streams the results
* via a {@link stream.Readable}.
*/
class DirectoryReader {
/**
* @param {string} dir - The absolute or relative directory path to read
* @param {object} [options] - User-specified options, if any (see {@link normalizeOptions})
* @param {object} internalOptions - Internal options that aren't part of the public API
* @class
*/
constructor (dir, options, internalOptions) {
this.options = options = normalizeOptions(options, internalOptions);
// Indicates whether we should keep reading
// This is set false if stream.Readable.push() returns false.
this.shouldRead = true;
// The directories to read
// (initialized with the top-level directory)
this.queue = [{
path: dir,
basePath: options.basePath,
posixBasePath: options.posixBasePath,
depth: 0
}];
// The number of directories that are currently being processed
this.pending = 0;
// The data that has been read, but not yet emitted
this.buffer = [];
this.stream = new Readable({ objectMode: true });
this.stream._read = () => {
// Start (or resume) reading
this.shouldRead = true;
// If we have data in the buffer, then send the next chunk
if (this.buffer.length > 0) {
this.pushFromBuffer();
}
// If we have directories queued, then start processing the next one
if (this.queue.length > 0) {
if (this.options.facade.sync) {
while (this.queue.length > 0) {
this.readNextDirectory();
}
}
else {
this.readNextDirectory();
}
}
this.checkForEOF();
};
}
/**
* Reads the next directory in the queue
*/
readNextDirectory () {
let facade = this.options.facade;
let dir = this.queue.shift();
this.pending++;
// Read the directory listing
call.safe(facade.fs.readdir, dir.path, (err, items) => {
if (err) {
// fs.readdir threw an error
this.emit('error', err);
return this.finishedReadingDirectory();
}
try {
// Process each item in the directory (simultaneously, if async)
facade.forEach(
items,
this.processItem.bind(this, dir),
this.finishedReadingDirectory.bind(this, dir)
);
}
catch (err2) {
// facade.forEach threw an error
// (probably because fs.readdir returned an invalid result)
this.emit('error', err2);
this.finishedReadingDirectory();
}
});
}
/**
* This method is called after all items in a directory have been processed.
*
* NOTE: This does not necessarily mean that the reader is finished, since there may still
* be other directories queued or pending.
*/
finishedReadingDirectory () {
this.pending--;
if (this.shouldRead) {
// If we have directories queued, then start processing the next one
if (this.queue.length > 0 && this.options.facade.async) {
this.readNextDirectory();
}
this.checkForEOF();
}
}
/**
* Determines whether the reader has finished processing all items in all directories.
* If so, then the "end" event is fired (via {@Readable#push})
*/
checkForEOF () {
if (this.buffer.length === 0 && // The stuff we've already read
this.pending === 0 && // The stuff we're currently reading
this.queue.length === 0) { // The stuff we haven't read yet
// There's no more stuff!
this.stream.push(null);
}
}
/**
* Processes a single item in a directory.
*
* If the item is a directory, and `option.deep` is enabled, then the item will be added
* to the directory queue.
*
* If the item meets the filter criteria, then it will be emitted to the reader's stream.
*
* @param {object} dir - A directory object from the queue
* @param {string} item - The name of the item (name only, no path)
* @param {function} done - A callback function that is called after the item has been processed
*/
processItem (dir, item, done) {
let stream = this.stream;
let options = this.options;
let itemPath = dir.basePath + item;
let posixPath = dir.posixBasePath + item;
let fullPath = path.join(dir.path, item);
// If `options.deep` is a number, and we've already recursed to the max depth,
// then there's no need to check fs.Stats to know if it's a directory.
// If `options.deep` is a function, then we'll need fs.Stats
let maxDepthReached = dir.depth >= options.recurseDepth;
// Do we need to call `fs.stat`?
let needStats =
!maxDepthReached || // we need the fs.Stats to know if it's a directory
options.stats || // the user wants fs.Stats objects returned
options.recurseFn || // we need fs.Stats for the recurse function
options.filterFn || // we need fs.Stats for the filter function
EventEmitter.listenerCount(stream, 'file') || // we need the fs.Stats to know if it's a file
EventEmitter.listenerCount(stream, 'directory') || // we need the fs.Stats to know if it's a directory
EventEmitter.listenerCount(stream, 'symlink'); // we need the fs.Stats to know if it's a symlink
// If we don't need stats, then exit early
if (!needStats) {
if (this.filter(itemPath, posixPath)) {
this.pushOrBuffer({ data: itemPath });
}
return done();
}
// Get the fs.Stats object for this path
stat(options.facade.fs, fullPath, (err, stats) => {
if (err) {
// fs.stat threw an error
this.emit('error', err);
return done();
}
try {
// Add the item's path to the fs.Stats object
// The base of this path, and its separators are determined by the options
// (i.e. options.basePath and options.sep)
stats.path = itemPath;
// Add depth of the path to the fs.Stats object for use this in the filter function
stats.depth = dir.depth;
if (this.shouldRecurse(stats, posixPath, maxDepthReached)) {
// Add this subdirectory to the queue
this.queue.push({
path: fullPath,
basePath: itemPath + options.sep,
posixBasePath: posixPath + '/',
depth: dir.depth + 1,
});
}
// Determine whether this item matches the filter criteria
if (this.filter(stats, posixPath)) {
this.pushOrBuffer({
data: options.stats ? stats : itemPath,
file: stats.isFile(),
directory: stats.isDirectory(),
symlink: stats.isSymbolicLink(),
});
}
done();
}
catch (err2) {
// An error occurred while processing the item
// (probably during a user-specified function, such as options.deep, options.filter, etc.)
this.emit('error', err2);
done();
}
});
}
/**
* Pushes the given chunk of data to the stream, or adds it to the buffer,
* depending on the state of the stream.
*
* @param {object} chunk
*/
pushOrBuffer (chunk) {
// Add the chunk to the buffer
this.buffer.push(chunk);
// If we're still reading, then immediately emit the next chunk in the buffer
// (which may or may not be the chunk that we just added)
if (this.shouldRead) {
this.pushFromBuffer();
}
}
/**
* Immediately pushes the next chunk in the buffer to the reader's stream.
* The "data" event will always be fired (via {@link Readable#push}).
* In addition, the "file", "directory", and/or "symlink" events may be fired,
* depending on the type of properties of the chunk.
*/
pushFromBuffer () {
let stream = this.stream;
let chunk = this.buffer.shift();
// Stream the data
try {
this.shouldRead = stream.push(chunk.data);
}
catch (err) {
this.emit('error', err);
}
// Also emit specific events, based on the type of chunk
chunk.file && this.emit('file', chunk.data);
chunk.symlink && this.emit('symlink', chunk.data);
chunk.directory && this.emit('directory', chunk.data);
}
/**
* Determines whether the given directory meets the user-specified recursion criteria.
* If the user didn't specify recursion criteria, then this function will default to true.
*
* @param {fs.Stats} stats - The directory's {@link fs.Stats} object
* @param {string} posixPath - The item's POSIX path (used for glob matching)
* @param {boolean} maxDepthReached - Whether we've already crawled the user-specified depth
* @returns {boolean}
*/
shouldRecurse (stats, posixPath, maxDepthReached) {
let options = this.options;
if (maxDepthReached) {
// We've already crawled to the maximum depth. So no more recursion.
return false;
}
else if (!stats.isDirectory()) {
// It's not a directory. So don't try to crawl it.
return false;
}
else if (options.recurseGlob) {
// Glob patterns are always tested against the POSIX path, even on Windows
// https://github.com/isaacs/node-glob#windows
return options.recurseGlob.test(posixPath);
}
else if (options.recurseRegExp) {
// Regular expressions are tested against the normal path
// (based on the OS or options.sep)
return options.recurseRegExp.test(stats.path);
}
else if (options.recurseFn) {
try {
// Run the user-specified recursion criteria
return options.recurseFn.call(null, stats);
}
catch (err) {
// An error occurred in the user's code.
// In Sync and Async modes, this will return an error.
// In Streaming mode, we emit an "error" event, but continue processing
this.emit('error', err);
}
}
else {
// No recursion function was specified, and we're within the maximum depth.
// So crawl this directory.
return true;
}
}
/**
* Determines whether the given item meets the user-specified filter criteria.
* If the user didn't specify a filter, then this function will always return true.
*
* @param {string|fs.Stats} value - Either the item's path, or the item's {@link fs.Stats} object
* @param {string} posixPath - The item's POSIX path (used for glob matching)
* @returns {boolean}
*/
filter (value, posixPath) {
let options = this.options;
if (options.filterGlob) {
// Glob patterns are always tested against the POSIX path, even on Windows
// https://github.com/isaacs/node-glob#windows
return options.filterGlob.test(posixPath);
}
else if (options.filterRegExp) {
// Regular expressions are tested against the normal path
// (based on the OS or options.sep)
return options.filterRegExp.test(value.path || value);
}
else if (options.filterFn) {
try {
// Run the user-specified filter function
return options.filterFn.call(null, value);
}
catch (err) {
// An error occurred in the user's code.
// In Sync and Async modes, this will return an error.
// In Streaming mode, we emit an "error" event, but continue processing
this.emit('error', err);
}
}
else {
// No filter was specified, so match everything
return true;
}
}
/**
* Emits an event. If one of the event listeners throws an error,
* then an "error" event is emitted.
*
* @param {string} eventName
* @param {*} data
*/
emit (eventName, data) {
let stream = this.stream;
try {
stream.emit(eventName, data);
}
catch (err) {
if (eventName === 'error') {
// Don't recursively emit "error" events.
// If the first one fails, then just throw
throw err;
}
else {
stream.emit('error', err);
}
}
}
}
module.exports = DirectoryReader;