Class ZipFS

Zip file-backed filesystem Implemented according to the standard: http://pkware.com/documents/casestudies/APPNOTE.TXT

While there are a few zip libraries for JavaScript (e.g. JSZip and zip.js), they are not a good match for ZenFS. In particular, these libraries perform a lot of unneeded data copying, and eagerly decompress every file in the zip file upon loading to check the CRC32. They also eagerly decode strings. Furthermore, these libraries duplicate functionality already present in ZenFS (e.g. UTF-8 decoding and binary data manipulation).

When the filesystem is instantiated, we determine the directory structure of the zip file as quickly as possible. We lazily decompress and check the CRC32 of files. We do not cache decompressed files; if this is a desired feature, it is best implemented as a generic file system wrapper that can cache data from arbitrary file systems.

Current limitations:

  • No encryption.
  • No ZIP64 support.
  • Read-only. Write support would require that we:
    • Keep track of changed/new files.
    • Compress changed files, and generate appropriate metadata for each.
    • Update file offsets for other files in the zip file.
    • Stream it out to a location. This isn't that bad, so we might do this at a later date.

Hierarchy

  • ReadonlyMixin & AsyncFSMethods & FileSystem<this>
    • ZipFS

Constructors

constructor

Properties

_mountPoint? _time attributes data directories eocd files id label name

Accessors

endOfCentralDirectory numberOfCentralDirectoryEntries

Methods

createFile createFileSync exists existsSync link linkSync metadata mkdir mkdirSync openFile openFileSync read readdir readdirSync readSync ready rename renameSync rmdir rmdirSync stat statSync sync syncSync toString unlink unlinkSync usage write writeSync computeEOCD

Constructors

constructor

  • new ZipFS(label: string, data: ArrayBufferLike): ZipFS

  • Parameters

    • label: string
    • data: ArrayBufferLike

    Returns ZipFS

Properties

Protected Optional Internal_mountPoint

_mountPoint?: string

The last place this file system was mounted

Protected_time

_time: number = ...

Readonlyattributes

attributes: ConstMap<FileSystemAttributes, keyof FileSystemAttributes, void>

See

FileSystemAttributes

Protecteddata

data: ArrayBufferLike

Protecteddirectories

directories: Map<string, Set<string>> = ...

Readonlyeocd

eocd: Header

Protectedfiles

files: Map<string, FileEntry> = ...

Readonlyid

id: number

A unique ID for this kind of file system. Currently unused internally, but could be used for partition tables or something

label

label: string

Readonlyname

name: string

The name for this file system. For example, tmpfs for an in memory one

Accessors

endOfCentralDirectory

numberOfCentralDirectoryEntries

  • get numberOfCentralDirectoryEntries(): number

  • Returns number

Methods

createFile

  • createFile(path: string, flag: string, mode: number): Promise<never>

  • Parameters

    • path: string
    • flag: string
    • mode: number

    Returns Promise<never>

  • createFile(
        path: string,
        flag: string,
        mode: number,
        options: CreationOptions,
    ): Promise<File>

  • Create the file at path with the given options. Then, open it with flag.

    Parameters

    • path: string
    • flag: string
    • mode: number
    • options: CreationOptions

    Returns Promise<File>

createFileSync

  • createFileSync(path: string, flag: string, mode: number): never

  • Parameters

    • path: string
    • flag: string
    • mode: number

    Returns never

  • createFileSync(
        path: string,
        flag: string,
        mode: number,
        options: CreationOptions,
    ): File

  • Create the file at path with the given options. Then, open it with flag.

    Parameters

    • path: string
    • flag: string
    • mode: number
    • options: CreationOptions

    Returns File

exists

  • exists(path: string): Promise<boolean>

  • Test whether or not path exists.

    Parameters

    • path: string

    Returns Promise<boolean>

existsSync

  • existsSync(path: string): boolean

  • Test whether or not path exists.

    Parameters

    • path: string

    Returns boolean

link

  • link(srcpath: string, dstpath: string): Promise<never>

  • Parameters

    • srcpath: string
    • dstpath: string

    Returns Promise<never>

  • link(target: string, link: string): Promise<void>

  • Parameters

    • target: string
    • link: string

    Returns Promise<void>

linkSync

  • linkSync(srcpath: string, dstpath: string): never

  • Parameters

    • srcpath: string
    • dstpath: string

    Returns never

  • linkSync(target: string, link: string): void

  • Parameters

    • target: string
    • link: string

    Returns void

metadata

  • metadata(): FileSystemMetadata

  • Returns FileSystemMetadata

mkdir

  • mkdir(path: string, mode: number): Promise<never>

  • Parameters

    • path: string
    • mode: number

    Returns Promise<never>

  • mkdir(path: string, mode: number, options: CreationOptions): Promise<void>

  • Parameters

    • path: string
    • mode: number
    • options: CreationOptions

    Returns Promise<void>

mkdirSync

  • mkdirSync(path: string, mode: number): never

  • Parameters

    • path: string
    • mode: number

    Returns never

  • mkdirSync(path: string, mode: number, options: CreationOptions): void

  • Parameters

    • path: string
    • mode: number
    • options: CreationOptions

    Returns void

AbstractopenFile

  • openFile(path: string, flag: string): Promise<File>

  • Opens the file at path with flag. The file must exist.

    Parameters

    • path: string

      The path to open.

    • flag: string

      The flag to use when opening the file.

    Returns Promise<File>

openFileSync

  • openFileSync(path: string, flag: string): File

  • Opens the file at path with flag. The file must exist.

    Parameters

    • path: string

      The path to open.

    • flag: string

      The flag to use when opening the file.

    Returns File

Abstractread

  • read(
        path: string,
        buffer: Uint8Array,
        offset: number,
        end: number,
    ): Promise<void>

  • Reads into a buffer

    Parameters

    • path: string
    • buffer: Uint8Array

      The buffer to read into. You must set the byteOffset and byteLength appropriately!

    • offset: number

      The offset into the file to start reading from

    • end: number

      The position in the file to stop reading

    Returns Promise<void>

Abstractreaddir

  • readdir(path: string): Promise<string[]>

  • Parameters

    • path: string

    Returns Promise<string[]>

readdirSync

  • readdirSync(path: string): string[]

  • Parameters

    • path: string

    Returns string[]

readSync

  • readSync(path: string, buffer: Uint8Array, offset: number, end: number): void

  • Reads into a buffer

    Parameters

    • path: string
    • buffer: Uint8Array

      The buffer to read into. You must set the byteOffset and byteLength appropriately!

    • offset: number

      The offset into the file to start reading from

    • end: number

      The position in the file to stop reading

    Returns void

ready

  • ready(): Promise<void>

  • Returns Promise<void>

rename

  • rename(oldPath: string, newPath: string): Promise<never>

  • Parameters

    • oldPath: string
    • newPath: string

    Returns Promise<never>

  • rename(oldPath: string, newPath: string): Promise<void>

  • Parameters

    • oldPath: string
    • newPath: string

    Returns Promise<void>

renameSync

  • renameSync(oldPath: string, newPath: string): never

  • Parameters

    • oldPath: string
    • newPath: string

    Returns never

  • renameSync(oldPath: string, newPath: string): void

  • Parameters

    • oldPath: string
    • newPath: string

    Returns void

rmdir

  • rmdir(path: string): Promise<never>

  • Parameters

    • path: string

    Returns Promise<never>

  • rmdir(path: string): Promise<void>

  • Parameters

    • path: string

    Returns Promise<void>

rmdirSync

  • rmdirSync(path: string): never

  • Parameters

    • path: string

    Returns never

  • rmdirSync(path: string): void

  • Parameters

    • path: string

    Returns void

Abstractstat

  • stat(path: string): Promise<Stats>

  • Parameters

    • path: string

    Returns Promise<Stats>

statSync

  • statSync(path: string): Stats

  • Parameters

    • path: string

    Returns Stats

sync

  • sync(
        path: string,
        data: Uint8Array,
        stats: Readonly<StatsLike<number>>,
    ): Promise<never>

  • Parameters

    • path: string
    • data: Uint8Array
    • stats: Readonly<StatsLike<number>>

    Returns Promise<never>

  • sync(
        path: string,
        data?: Uint8Array,
        stats?: Readonly<Partial<StatsLike>>,
    ): Promise<void>

  • Parameters

    • path: string
    • Optionaldata: Uint8Array
    • Optionalstats: Readonly<Partial<StatsLike>>

    Returns Promise<void>

syncSync

  • syncSync(
        path: string,
        data: Uint8Array,
        stats: Readonly<StatsLike<number>>,
    ): never

  • Parameters

    • path: string
    • data: Uint8Array
    • stats: Readonly<StatsLike<number>>

    Returns never

  • syncSync(
        path: string,
        data?: Uint8Array,
        stats?: Readonly<Partial<StatsLike>>,
    ): void

  • Parameters

    • path: string
    • Optionaldata: Uint8Array
    • Optionalstats: Readonly<Partial<StatsLike>>

    Returns void

toString

  • toString(): string

  • Returns string

unlink

  • unlink(path: string): Promise<never>

  • Parameters

    • path: string

    Returns Promise<never>

  • unlink(path: string): Promise<void>

  • Parameters

    • path: string

    Returns Promise<void>

unlinkSync

  • unlinkSync(path: string): never

  • Parameters

    • path: string

    Returns never

  • unlinkSync(path: string): void

  • Parameters

    • path: string

    Returns void

usage

  • usage(): UsageInfo
  • Experimental

    Default implementation.

    Returns UsageInfo

    Todo

    Implement

write

  • write(path: string, buffer: Uint8Array, offset: number): Promise<never>

  • Parameters

    • path: string
    • buffer: Uint8Array
    • offset: number

    Returns Promise<never>

  • write(path: string, buffer: Uint8Array, offset: number): Promise<void>

  • Writes a buffer to a file

    Parameters

    • path: string
    • buffer: Uint8Array

      The buffer to write. You must set the byteOffset and byteLength appropriately!

    • offset: number

      The offset in the file to start writing

    Returns Promise<void>

writeSync

  • writeSync(path: string, buffer: Uint8Array, offset: number): Promise<never>

  • Parameters

    • path: string
    • buffer: Uint8Array
    • offset: number

    Returns Promise<never>

  • writeSync(path: string, buffer: Uint8Array, offset: number): void

  • Writes a buffer to a file

    Parameters

    • path: string
    • buffer: Uint8Array

      The buffer to write. You must set the byteOffset and byteLength appropriately!

    • offset: number

      The offset in the file to start writing

    Returns void

Protected StaticcomputeEOCD

  • computeEOCD(data: ArrayBufferLike): Header

  • Locates the end of central directory record at the end of the file. Throws an exception if it cannot be found.

    Parameters

    • data: ArrayBufferLike

    Returns Header

    Remarks

    Unfortunately, the comment is variable size and up to 64K in size. We assume that the magic signature does not appear in the comment, and in the bytes between the comment and the signature. Other ZIP implementations make this same assumption, since the alternative is to read thread every entry in the file.

    Offsets in this function are negative (i.e. from the end of the file).

    There is no byte alignment on the comment

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