Class AsyncMirror

AsyncMirrorFS mirrors a synchronous filesystem into an asynchronous filesystem by:

Performing operations over the in-memory copy, while asynchronously pipelining them to the backing store.
During application loading, the contents of the async file system can be reloaded into the synchronous store, if desired.

The two stores will be kept in sync. The most common use-case is to pair a synchronous in-memory filesystem with an asynchronous backing store.

Example: Mirroring an IndexedDB file system to an in memory file system. Now, you can use IndexedDB synchronously.

BrowserFS.configure({
  fs: "AsyncMirror",
  options: {
    sync: { fs: "InMemory" },
    async: { fs: "IndexedDB" }
  }
}, function(e) {
  // BrowserFS is initialized and ready-to-use!
});

Or, alternatively:

BrowserFS.Backend.IndexedDB.Create(function(e, idbfs) {
  BrowserFS.Backend.InMemory.Create(function(e, inMemory) {
    BrowserFS.Backend.AsyncMirror({
      sync: inMemory, async: idbfs
    }, function(e, mirrored) {
      BrowserFS.initialize(mirrored);
    });
  });
});

Hierarchy

SynchronousFileSystem
- AsyncMirror

Constructors

constructor

new AsyncMirror(__namedParameters): AsyncMirror
Mirrors the synchronous file system into the asynchronous file system.
Parameters
- __namedParameters: AsyncMirror.Options
Returns AsyncMirror
Overrides SynchronousFileSystem.constructor
- Defined in src/backends/AsyncMirror.ts:136

Properties

`Private` _async

_async: FileSystem

`Private` _initializeCallbacks

_initializeCallbacks: ((e?) => void)[] = []

Type declaration

- (e?): void
- Parameters
  - Optional e: ApiError
  Returns void

`Private` _isInitialized

_isInitialized: boolean = false

`Private` _queue

_queue: AsyncOperation[] = []

Queue of pending asynchronous operations.

`Private` _queueRunning

_queueRunning: boolean = false

`Protected` _ready

_ready: Promise<AsyncMirror> = ...

`Private` _sync

_sync: FileSystem

`Static` Create

Create: any = ...

`Static` `Readonly` Name

Name: "AsyncMirror" = 'AsyncMirror'

Accessors

metadata

get metadata(): FileSystemMetadata
Returns FileSystemMetadata
Overrides SynchronousFileSystem.metadata
- Defined in src/backends/AsyncMirror.ts:143

Methods

`Private` _initialize

_initialize(): Promise<AsyncMirror>
Called once to load up files from async storage into sync storage.

Returns Promise<AsyncMirror>
- Defined in src/backends/AsyncMirror.ts:239

_syncSync

_syncSync(fd): void
Parameters
- fd: PreloadFile<AsyncMirror>
Returns void
- Defined in src/backends/AsyncMirror.ts:152

access

access(p, mode, cred): Promise<void>
Asynchronous access.
Parameters
- p: string
- mode: number
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.access
- Defined in src/filesystem.ts:676

accessSync

accessSync(p, mode, cred): void
Synchronous access.
Parameters
- p: string
- mode: number
- cred: Cred
Returns void
Inherited from SynchronousFileSystem.accessSync
- Defined in src/filesystem.ts:384

appendFile

appendFile(fname, data, flag, mode, cred): Promise<void>
Asynchronously append data to a file, creating the file if it not yet exists.
Parameters
- fname: string
- data: Uint8Array
- flag: FileFlag
- mode: number
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.appendFile
- Defined in src/filesystem.ts:608

appendFileSync

appendFileSync(fname, data, flag, mode, cred): void
Synchronously append data to a file, creating the file if it not yet exists.
Parameters
- fname: string
- data: Uint8Array
- flag: FileFlag
- mode: number
- cred: Cred
Returns void
Inherited from SynchronousFileSystem.appendFileSync
- Defined in src/filesystem.ts:619

chmod

chmod(p, mode, cred): Promise<void>
Asynchronous chmod.
Parameters
- p: string
- mode: number
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.chmod
- Defined in src/filesystem.ts:708

chmodSync

chmodSync(p, mode, cred): void
Synchronous chmod.
Parameters
- p: string
- mode: number
- cred: Cred
Returns void
Overrides SynchronousFileSystem.chmodSync
- Defined in src/backends/AsyncMirror.ts:212

chown

chown(p, new_uid, new_gid, cred): Promise<void>
Asynchronous chown.
Parameters
- p: string
- new_uid: number
- new_gid: number
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.chown
- Defined in src/filesystem.ts:712

chownSync

chownSync(p, new_uid, new_gid, cred): void
Synchronous chown.
Parameters
- p: string
- new_uid: number
- new_gid: number
- cred: Cred
Returns void
Overrides SynchronousFileSystem.chownSync
- Defined in src/backends/AsyncMirror.ts:220

createFile

createFile(p, flag, mode, cred): Promise<File>
Create the file at path p with the given mode. Then, open it with the given flag.
Parameters
- p: string
- flag: FileFlag
- mode: number
- cred: Cred
Returns Promise<File>
Inherited from SynchronousFileSystem.createFile
- Defined in src/filesystem.ts:338

createFileSync

createFileSync(p, flag, mode, cred): File
Create the file at path p with the given mode. Then, open it with the given flag.
Parameters
- p: string
- flag: FileFlag
- mode: number
- cred: Cred
Returns File
Inherited from SynchronousFileSystem.createFileSync
- Defined in src/filesystem.ts:412

`Private` enqueueOp

enqueueOp(op): void
Parameters
- op: AsyncOperation
Returns void
- Defined in src/backends/AsyncMirror.ts:275

exists

exists(p, cred): Promise<boolean>
Test whether or not the given path exists by checking with the file system. Then call the callback argument with either true or false.
Parameters
- p: string
- cred: Cred
Returns Promise<boolean>
Inherited from SynchronousFileSystem.exists
- Defined in src/filesystem.ts:482

existsSync

existsSync(p, cred): boolean
Test whether or not the given path exists by checking with the file system.
Parameters
- p: string
- cred: Cred
Returns boolean
Overrides SynchronousFileSystem.existsSync
- Defined in src/backends/AsyncMirror.ts:208

link

link(srcpath, dstpath, cred): Promise<void>
Asynchronous link.
Parameters
- srcpath: string
- dstpath: string
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.link
- Defined in src/filesystem.ts:720

linkSync

linkSync(srcpath, dstpath, cred): void
Synchronous link.
Parameters
- srcpath: string
- dstpath: string
- cred: Cred
Returns void
Inherited from SynchronousFileSystem.linkSync
- Defined in src/filesystem.ts:651

mkdir

mkdir(p, mode, cred): Promise<void>
Asynchronous mkdir.
Parameters
- p: string
- mode: number
  
  Mode to make the directory using. Can be ignored if the filesystem doesn't support permissions.
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.mkdir
- Defined in src/filesystem.ts:700

mkdirSync

mkdirSync(p, mode, cred): void
Synchronous mkdir.
Parameters
- p: string
- mode: number
  
  Mode to make the directory using. Can be ignored if the filesystem doesn't support permissions.
- cred: Cred
Returns void
Overrides SynchronousFileSystem.mkdirSync
- Defined in src/backends/AsyncMirror.ts:196

open

open(p, flags, mode, cred): Promise<File>
Asynchronous file open.
Parameters
- p: string
- flags: FileFlag
- mode: number
  
  Mode to use to open the file. Can be ignored if the filesystem doesn't support permissions.
- cred: Cred
Returns Promise<File>

See
http://www.manpagez.com/man/2/open/
Inherited from SynchronousFileSystem.open
- Defined in src/filesystem.ts:688

openFile

openFile(p, flag, cred): Promise<File>
Opens the file at path p with the given flag. The file must exist.
Parameters
- p: string
  
  The path to open.
- flag: FileFlag
  
  The flag to use when opening the file.
- cred: Cred
Returns Promise<File>
Inherited from SynchronousFileSystem.openFile
- Defined in src/filesystem.ts:331

openFileSync

openFileSync(p, flag, cred): File
Opens the file at path p with the given flag. The file must exist.
Parameters
- p: string
  
  The path to open.
- flag: FileFlag
  
  The flag to use when opening the file.
- cred: Cred
Returns File
A File object corresponding to the opened file.
Inherited from SynchronousFileSystem.openFileSync
- Defined in src/filesystem.ts:405

openSync

openSync(p, flag, mode, cred): File
Synchronous file open.
Parameters
- p: string
- flag: FileFlag
- mode: number
  
  Mode to use to open the file. Can be ignored if the filesystem doesn't support permissions.
- cred: Cred
Returns File

See
http://www.manpagez.com/man/2/open/
Overrides SynchronousFileSystem.openSync
- Defined in src/backends/AsyncMirror.ts:173

readFile

readFile(fname, flag, cred): Promise<Uint8Array>
Asynchronously reads the entire contents of a file.
Parameters
- fname: string
- flag: FileFlag
- cred: Cred
Returns Promise<Uint8Array>
Inherited from SynchronousFileSystem.readFile
- Defined in src/filesystem.ts:554

readFileSync

readFileSync(fname, flag, cred): Uint8Array
Synchronously reads the entire contents of a file.
Parameters
- fname: string
- flag: FileFlag
- cred: Cred
Returns Uint8Array
Inherited from SynchronousFileSystem.readFileSync
- Defined in src/filesystem.ts:568

readdir

readdir(p, cred): Promise<string[]>
Asynchronous readdir. Reads the contents of a directory.

The callback gets two arguments (err, files) where files is an array of the names of the files in the directory excluding '.' and '..'.
Parameters
- p: string
- cred: Cred
Returns Promise<string[]>
Inherited from SynchronousFileSystem.readdir
- Defined in src/filesystem.ts:704

readdirSync

readdirSync(p, cred): string[]
Synchronous readdir. Reads the contents of a directory.
Parameters
- p: string
- cred: Cred
Returns string[]
Overrides SynchronousFileSystem.readdirSync
- Defined in src/backends/AsyncMirror.ts:204

readlink

readlink(p, cred): Promise<string>
Asynchronous readlink.
Parameters
- p: string
- cred: Cred
Returns Promise<string>
Inherited from SynchronousFileSystem.readlink
- Defined in src/filesystem.ts:728

readlinkSync

readlinkSync(p, cred): string
Synchronous readlink.
Parameters
- p: string
- cred: Cred
Returns string
Inherited from SynchronousFileSystem.readlinkSync
- Defined in src/filesystem.ts:663

realpath

realpath(p, cred): Promise<string>
Asynchronous realpath. The callback gets two arguments (err, resolvedPath).

Note that the Node API will resolve path to an absolute path.
Parameters
- p: string
- cred: Cred
Returns Promise<string>
Inherited from SynchronousFileSystem.realpath
- Defined in src/filesystem.ts:498

realpathSync

realpathSync(p, cred): string
Synchronous realpath.

Note that the Node API will resolve path to an absolute path.
Parameters
- p: string
- cred: Cred
Returns string
Inherited from SynchronousFileSystem.realpathSync
- Defined in src/filesystem.ts:517

rename

rename(oldPath, newPath, cred): Promise<void>
Asynchronous rename. No arguments other than a possible exception are given to the completion callback.
Parameters
- oldPath: string
- newPath: string
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.rename
- Defined in src/filesystem.ts:680

renameSync

renameSync(oldPath, newPath, cred): void
Synchronous rename.
Parameters
- oldPath: string
- newPath: string
- cred: Cred
Returns void
Overrides SynchronousFileSystem.renameSync
- Defined in src/backends/AsyncMirror.ts:161

rmdir

rmdir(p, cred): Promise<void>
Asynchronous rmdir.
Parameters
- p: string
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.rmdir
- Defined in src/filesystem.ts:696

rmdirSync

rmdirSync(p, cred): void
Synchronous rmdir.
Parameters
- p: string
- cred: Cred
Returns void
Overrides SynchronousFileSystem.rmdirSync
- Defined in src/backends/AsyncMirror.ts:188

stat

stat(p, cred): Promise<Stats>
Asynchronous stat.
Parameters
- p: string
- cred: Cred
Returns Promise<Stats>
Inherited from SynchronousFileSystem.stat
- Defined in src/filesystem.ts:684

statSync

statSync(p, cred): Stats
Synchronous stat.
Parameters
- p: string
- cred: Cred
Returns Stats
Overrides SynchronousFileSystem.statSync
- Defined in src/backends/AsyncMirror.ts:169

symlink

symlink(srcpath, dstpath, type, cred): Promise<void>
Asynchronous symlink.
Parameters
- srcpath: string
- dstpath: string
- type: string
  
  can be either 'dir' or 'file'
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.symlink
- Defined in src/filesystem.ts:724

symlinkSync

symlinkSync(srcpath, dstpath, type, cred): void
Synchronous symlink.
Parameters
- srcpath: string
- dstpath: string
- type: string
  
  can be either 'dir' or 'file'
- cred: Cred
Returns void
Inherited from SynchronousFileSystem.symlinkSync
- Defined in src/filesystem.ts:657

truncate

truncate(p, len, cred): Promise<void>
Asynchronous truncate.
Parameters
- p: string
- len: number
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.truncate
- Defined in src/filesystem.ts:537

truncateSync

truncateSync(p, len, cred): void
Synchronous truncate.
Parameters
- p: string
- len: number
- cred: Cred
Returns void
Inherited from SynchronousFileSystem.truncateSync
- Defined in src/filesystem.ts:545

unlink

unlink(p, cred): Promise<void>
Asynchronous unlink.
Parameters
- p: string
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.unlink
- Defined in src/filesystem.ts:692

unlinkSync

unlinkSync(p, cred): void
Synchronous unlink.
Parameters
- p: string
- cred: Cred
Returns void
Overrides SynchronousFileSystem.unlinkSync
- Defined in src/backends/AsyncMirror.ts:180

utimes

utimes(p, atime, mtime, cred): Promise<void>
Change file timestamps of the file referenced by the supplied path.
Parameters
- p: string
- atime: Date
- mtime: Date
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.utimes
- Defined in src/filesystem.ts:716

utimesSync

utimesSync(p, atime, mtime, cred): void
Change file timestamps of the file referenced by the supplied path.
Parameters
- p: string
- atime: Date
- mtime: Date
- cred: Cred
Returns void
Overrides SynchronousFileSystem.utimesSync
- Defined in src/backends/AsyncMirror.ts:228

whenReady

whenReady(): Promise<AsyncMirror>
Returns Promise<AsyncMirror>
Inherited from SynchronousFileSystem.whenReady
- Defined in src/filesystem.ts:322

writeFile

writeFile(fname, data, flag, mode, cred): Promise<void>
Asynchronously writes data to a file, replacing the file if it already exists.

The encoding option is ignored if data is a buffer.
Parameters
- fname: string
- data: Uint8Array
- flag: FileFlag
- mode: number
- cred: Cred
Returns Promise<void>
Inherited from SynchronousFileSystem.writeFile
- Defined in src/filesystem.ts:582

writeFileSync

writeFileSync(fname, data, flag, mode, cred): void
Synchronously writes data to a file, replacing the file if it already exists.

The encoding option is ignored if data is a buffer.
Parameters
- fname: string
- data: Uint8Array
- flag: FileFlag
- mode: number
- cred: Cred
Returns void
Inherited from SynchronousFileSystem.writeFileSync
- Defined in src/filesystem.ts:595

`Static` isAvailable

isAvailable(): boolean
Returns boolean
- Defined in src/backends/AsyncMirror.ts:115

Class AsyncMirror

Hierarchy

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Parameters

__namedParameters: AsyncMirror.Options

Returns AsyncMirror

Properties

Private _async

Private _initializeCallbacks

Type declaration

Parameters

Optional e: ApiError

Returns void

Private _isInitialized

Private _queue

Private _queueRunning

Protected _ready

Private _sync

Static Create

Static Readonly Name

Accessors

metadata

Returns FileSystemMetadata

Methods

Private _initialize

Returns Promise<AsyncMirror>

_syncSync

Parameters

fd: PreloadFile<AsyncMirror>

Returns void

access

Parameters

p: string

mode: number

cred: Cred

Returns Promise<void>

accessSync

Parameters

p: string

mode: number

cred: Cred

Returns void

appendFile

Parameters

fname: string

data: Uint8Array

flag: FileFlag

mode: number

cred: Cred

Returns Promise<void>

appendFileSync

Parameters

fname: string

data: Uint8Array

flag: FileFlag

mode: number

cred: Cred

Returns void

chmod

Parameters

p: string

mode: number

cred: Cred

Returns Promise<void>

chmodSync

Parameters

p: string

mode: number

cred: Cred

Returns void

chown

Parameters

p: string

new_uid: number

`Private` _async

`Private` _initializeCallbacks

`Optional` e: ApiError

`Private` _isInitialized

`Private` _queue

`Private` _queueRunning

`Protected` _ready

`Private` _sync

`Static` Create

`Static` `Readonly` Name

`Private` _initialize

`Private` enqueueOp