overleaf/libraries/overleaf-editor-core/lib/file_map.js

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// @ts-check
'use strict'
const _ = require('lodash')
const assert = require('check-types').assert
const OError = require('@overleaf/o-error')
const pMap = require('p-map')
const File = require('./file')
const safePathname = require('./safe_pathname')
/**
* @import { RawFile, RawFileMap } from './types'
*
* @typedef {Record<String, File | null>} FileMapData
*/
class PathnameError extends OError {}
class NonUniquePathnameError extends PathnameError {
/**
* @param {string[]} pathnames
*/
constructor(pathnames) {
super('pathnames are not unique: ' + pathnames, { pathnames })
this.pathnames = pathnames
}
}
class BadPathnameError extends PathnameError {
/**
* @param {string} pathname
*/
constructor(pathname) {
super(pathname + ' is not a valid pathname', { pathname })
this.pathname = pathname
}
}
class PathnameConflictError extends PathnameError {
/**
* @param {string} pathname
*/
constructor(pathname) {
super(`pathname '${pathname}' conflicts with another file`, { pathname })
this.pathname = pathname
}
}
class FileNotFoundError extends PathnameError {
/**
* @param {string} pathname
*/
constructor(pathname) {
super(`file ${pathname} does not exist`, { pathname })
this.pathname = pathname
}
}
/**
* A set of {@link File}s. Several properties are enforced on the pathnames:
*
* 1. File names and paths are case sensitive and can differ by case alone. This
* is consistent with most Linux file systems, but it is not consistent with
* Windows or OS X. Ideally, we would be case-preserving and case insensitive,
* like they are. And we used to be, but it caused too many incompatibilities
* with the old system, which was case sensitive. See
* https://github.com/overleaf/overleaf-ot-prototype/blob/
* 19ed046c09f5a4d14fa12b3ea813ce0d977af88a/editor/core/lib/file_map.js
* for an implementation of this map with those properties.
*
* 2. Uniqueness: No two pathnames are the same.
*
* 3. No type conflicts: A pathname cannot refer to both a file and a directory
* within the same snapshot. That is, you can't have pathnames `a` and `a/b` in
* the same file map; {@see FileMap#wouldConflict}.
*/
class FileMap {
static PathnameError = PathnameError
static NonUniquePathnameError = NonUniquePathnameError
static BadPathnameError = BadPathnameError
static PathnameConflictError = PathnameConflictError
static FileNotFoundError = FileNotFoundError
/**
* @param {Record<String, File | null>} files
*/
constructor(files) {
// create bare object for use as Map
// http://ryanmorr.com/true-hash-maps-in-javascript/
/** @type FileMapData */
this.files = Object.create(null)
_.assign(this.files, files)
checkPathnamesAreUnique(this.files)
checkPathnamesDoNotConflict(this)
}
/**
* @param {RawFileMap} raw
* @returns {FileMap}
*/
static fromRaw(raw) {
assert.object(raw, 'bad raw files')
return new FileMap(_.mapValues(raw, File.fromRaw))
}
/**
* Convert to raw object for serialization.
*
* @return {RawFileMap}
*/
toRaw() {
/**
* @param {File} file
* @return {RawFile}
*/
function fileToRaw(file) {
return file.toRaw()
}
// TODO(das7pad): refine types to enforce no nulls in FileMapData
// @ts-ignore
return _.mapValues(this.files, fileToRaw)
}
/**
* Create the given file.
*
* @param {string} pathname
* @param {File} file
*/
addFile(pathname, file) {
checkPathname(pathname)
assert.object(file, 'bad file')
// TODO(das7pad): make ignoredPathname argument fully optional
// @ts-ignore
checkNewPathnameDoesNotConflict(this, pathname)
addFile(this.files, pathname, file)
}
/**
* Remove the given file.
*
* @param {string} pathname
*/
removeFile(pathname) {
checkPathname(pathname)
const key = findPathnameKey(this.files, pathname)
if (!key) {
throw new FileMap.FileNotFoundError(pathname)
}
delete this.files[key]
}
/**
* Move or remove a file. If the origin file does not exist, or if the old
* and new paths are identical, this has no effect.
*
* @param {string} pathname
* @param {string} newPathname if a blank string, {@link FileMap#removeFile}
*/
moveFile(pathname, newPathname) {
if (pathname === newPathname) return
if (newPathname === '') return this.removeFile(pathname)
checkPathname(pathname)
checkPathname(newPathname)
checkNewPathnameDoesNotConflict(this, newPathname, pathname)
const key = findPathnameKey(this.files, pathname)
if (!key) {
throw new FileMap.FileNotFoundError(pathname)
}
const file = this.files[key]
delete this.files[key]
addFile(this.files, newPathname, file)
}
/**
* The number of files in the file map.
*
* @return {number}
*/
countFiles() {
return _.size(this.files)
}
/**
* Get a file by its pathname.
*
* @param {string} pathname
* @return {File | null | undefined}
*/
getFile(pathname) {
const key = findPathnameKey(this.files, pathname)
if (key) return this.files[key]
}
/**
* Whether the given pathname conflicts with any file in the map.
*
* Paths conflict in type if one path is a strict prefix of the other path. For
* example, 'a/b' conflicts with 'a', because in the former case 'a' is a
* folder, but in the latter case it is a file. Similarly, the pathname 'a/b/c'
* conflicts with 'a' and 'a/b', but it does not conflict with 'a/b/c', 'a/x',
* or 'a/b/x'. (In our case, identical paths don't conflict, because AddFile
* and MoveFile overwrite existing files.)
*
* @param {string} pathname
* @param {string?} ignoredPathname pretend this pathname does not exist
*/
wouldConflict(pathname, ignoredPathname) {
checkPathname(pathname)
assert.maybe.string(ignoredPathname)
const pathnames = this.getPathnames()
const dirname = pathname + '/'
// Check the filemap to see whether the supplied pathname is a
// parent of any entry, or any entry is a parent of the pathname.
for (let i = 0; i < pathnames.length; i++) {
// First check if pathname is a strict prefix of pathnames[i] (and that
// pathnames[i] is not ignored)
if (
pathnames[i].startsWith(dirname) &&
!pathnamesEqual(pathnames[i], ignoredPathname)
) {
return true
}
// Now make the reverse check, whether pathnames[i] is a strict prefix of
// pathname. To avoid expensive string concatenation on each pathname we
// first perform a partial check with a.startsWith(b), and then do the
// full check for a subsequent '/' if this passes. This saves about 25%
// of the runtime. Again only return a conflict if pathnames[i] is not
// ignored.
if (
pathname.startsWith(pathnames[i]) &&
pathname.length > pathnames[i].length &&
pathname[pathnames[i].length] === '/' &&
!pathnamesEqual(pathnames[i], ignoredPathname)
) {
return true
}
}
// No conflicts - after excluding ignoredPathname, there were no entries
// which were a strict prefix of pathname, and pathname was not a strict
// prefix of any entry.
return false
}
/** @see Snapshot#getFilePathnames */
getPathnames() {
return _.keys(this.files)
}
/**
* Map the files in this map to new values.
* @template T
* @param {(file: File | null, path: string) => T} iteratee
* @return {Record<String, T>}
*/
map(iteratee) {
return _.mapValues(this.files, iteratee)
}
/**
* Map the files in this map to new values asynchronously, with an optional
* limit on concurrency.
* @template T
* @param {(file: File | null | undefined, path: string, pathnames: string[]) => T} iteratee
* @param {number} [concurrency]
* @return {Promise<Record<String, T>>}
*/
async mapAsync(iteratee, concurrency) {
assert.maybe.number(concurrency, 'bad concurrency')
const pathnames = this.getPathnames()
const files = await pMap(
pathnames,
file => {
return iteratee(this.getFile(file), file, pathnames)
},
{ concurrency: concurrency || 1 }
)
return _.zipObject(pathnames, files)
}
}
/**
* @param {string} pathname0
* @param {string?} pathname1
* @returns {boolean}
*/
function pathnamesEqual(pathname0, pathname1) {
return pathname0 === pathname1
}
/**
* @param {FileMapData} files
* @returns {boolean}
*/
function pathnamesAreUnique(files) {
const keys = _.keys(files)
return _.uniqWith(keys, pathnamesEqual).length === keys.length
}
/**
* @param {FileMapData} files
*/
function checkPathnamesAreUnique(files) {
if (pathnamesAreUnique(files)) return
throw new FileMap.NonUniquePathnameError(_.keys(files))
}
/**
* @param {string} pathname
*/
function checkPathname(pathname) {
assert.nonEmptyString(pathname, 'bad pathname')
if (safePathname.isClean(pathname)) return
throw new FileMap.BadPathnameError(pathname)
}
/**
* @param {FileMap} fileMap
* @param {string} pathname
* @param {string?} ignoredPathname
*/
function checkNewPathnameDoesNotConflict(fileMap, pathname, ignoredPathname) {
if (fileMap.wouldConflict(pathname, ignoredPathname)) {
throw new FileMap.PathnameConflictError(pathname)
}
}
/**
* @param {FileMap} fileMap
*/
function checkPathnamesDoNotConflict(fileMap) {
const pathnames = fileMap.getPathnames()
// check pathnames for validity first
pathnames.forEach(checkPathname)
// convert pathnames to candidate directory names
const dirnames = []
for (let i = 0; i < pathnames.length; i++) {
dirnames[i] = pathnames[i] + '/'
}
// sort in lexical order and check if one directory contains another
dirnames.sort()
for (let i = 0; i < dirnames.length - 1; i++) {
if (dirnames[i + 1].startsWith(dirnames[i])) {
// strip trailing slash to get original pathname
const conflictPathname = dirnames[i + 1].substr(0, -1)
throw new FileMap.PathnameConflictError(conflictPathname)
}
}
}
/**
* This function is somewhat vestigial: it was used when this map used
* case-insensitive pathname comparison. We could probably simplify some of the
* logic in the callers, but in the hope that we will one day return to
* case-insensitive semantics, we've just left things as-is for now.
*
* TODO(das7pad): In a followup, inline this function and make types stricter.
*
* @param {FileMapData} files
* @param {string} pathname
* @returns {string | undefined}
*/
function findPathnameKey(files, pathname) {
// we can check for the key without worrying about properties
// in the prototype because we are now using a bare object/
if (pathname in files) return pathname
}
/**
* @param {FileMapData} files
* @param {string} pathname
* @param {File?} file
*/
function addFile(files, pathname, file) {
const key = findPathnameKey(files, pathname)
if (key) delete files[key]
files[pathname] = file
}
module.exports = FileMap