memphis

package module
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 Go to latest Published: Sep 2, 2023 License: Apache-2.0 Imports: 14 Imported by: 0

README

Memphis

Status: Minimum Viable

Memphis is a virtual (memory) file system for golang. It provides the same functionality (and is meant to be used as) a backing store for billy, rio, and others.

Memphis stores can also be generated from on-disk directory trees. File contents of unmodified files will be read from disk, while write requests to a file will transition them to in-memory content buffers.

License

SPDX-License-Identifier: Apache-2.0

Documentation

Index

Constants

View Source 
const Separator = "/"

Separator provides a stable path separator the memphis FS expects.

Variables

View Source 
var ErrExists = errors.New("EExists")

ErrExists indicates a file already exists at a location

View Source 
var ErrNotDir = errors.New("ENotDir")

ErrNotDir indicates the proposed location is not a directory

Functions

This section is empty.

Types

type Billy 

type Billy struct {
	// contains filtered or unexported fields
}

Billy wraps a filesystem subtree in the billy filesystem interface

func (*Billy) Capabilities 

func (b *Billy) Capabilities() billy.Capability

Capabilities tells billy what this FS can do

func (*Billy) Chmod 

func (b *Billy) Chmod(name string, mode os.FileMode) error

Chmod changes file permissions

func (*Billy) Chown 

func (b *Billy) Chown(name string, uid, gid int) error

Chown changes file ownership

func (*Billy) Chroot 

func (b *Billy) Chroot(path string) (billy.Filesystem, error)

Chroot returns a subtree of the filesystem

func (*Billy) Chtimes 

func (b *Billy) Chtimes(name string, atime time.Time, mtime time.Time) error

Chtimes changes file access time

func (*Billy) Create 

func (b *Billy) Create(filename string) (billy.File, error)

Create makes a new empty file

func (*Billy) Join 

func (b *Billy) Join(elem ...string) string

Join constructs a path

func (*Billy) Lchown 

func (b *Billy) Lchown(name string, uid, gid int) error

Lchown changes symlink ownership

func (*Billy) Lstat 

func (b *Billy) Lstat(filename string) (os.FileInfo, error)

Lstat provides symlink info

func (*Billy) MkdirAll 

func (b *Billy) MkdirAll(filename string, perm os.FileMode) error

MkdirAll creates a new directory

func (*Billy) Open 

func (b *Billy) Open(filename string) (billy.File, error)

Open is a shortcut to openfile

func (*Billy) OpenFile 

func (b *Billy) OpenFile(filename string, flag int, perm os.FileMode) (billy.File, error)

OpenFile opens a file for access

func (*Billy) ReadDir 

func (b *Billy) ReadDir(path string) ([]os.FileInfo, error)

ReadDir lists directory contents 

func (b *Billy) Readlink(link string) (string, error)

Readlink returns symlink contents

func (*Billy) Remove 

func (b *Billy) Remove(filename string) error

Remove deletes a file

func (*Billy) Rename 

func (b *Billy) Rename(oldpath, newpath string) error

Rename a file

func (*Billy) Root 

func (b *Billy) Root() string

Root prints the path of the current fs root

func (*Billy) Stat 

func (b *Billy) Stat(filename string) (os.FileInfo, error)

Stat returns file metadata 

func (b *Billy) Symlink(target, link string) error

Symlink creates a symbolic link

func (*Billy) TempFile 

func (b *Billy) TempFile(dir, prefix string) (billy.File, error)

TempFile create an empty tempfile

type BillyFile 

type BillyFile struct {
	*File
	// contains filtered or unexported fields
}

BillyFile is a wrapper to file contents implementing the implicit position cursor for read/write

func (*BillyFile) Close 

func (bf *BillyFile) Close() error

Close closes the file - not relevant in this implementation.

func (*BillyFile) Lock 

func (bf *BillyFile) Lock() error

Lock is not used in this implementation

func (*BillyFile) Read 

func (bf *BillyFile) Read(buf []byte) (n int, err error)

Read is a more common implementation implemented by ReadAt

func (*BillyFile) ReadAt 

func (bf *BillyFile) ReadAt(buf []byte, offset int64) (n int, err error)

ReadAt is a passthrough.

func (*BillyFile) Seek 

func (bf *BillyFile) Seek(offset int64, whence int) (int64, error)

Seek changes file position

func (*BillyFile) Truncate 

func (bf *BillyFile) Truncate(size int64) error

Truncate changes the size of the file contents

func (*BillyFile) Unlock 

func (bf *BillyFile) Unlock() error

Unlock is not used in this implementation

func (*BillyFile) Write 

func (bf *BillyFile) Write(buf []byte) (n int, err error)

Write modifies file contents

func (*BillyFile) WriteAt 

func (bf *BillyFile) WriteAt(buf []byte, offset int64) (n int, err error)

WriteAt is a passthrough.

type DirMeta 

type DirMeta struct {
	*Tree
	// contains filtered or unexported fields
}

DirMeta is a struct of metadata about a directory

func (*DirMeta) IsDir 

func (d *DirMeta) IsDir() bool

IsDir is true for directories

func (*DirMeta) ModTime 

func (d *DirMeta) ModTime() time.Time

ModTime is when the directory was last modified

func (*DirMeta) Mode 

func (d *DirMeta) Mode() os.FileMode

Mode is the os.FileMode (permissions) for the directory

func (*DirMeta) Name 

func (d *DirMeta) Name() string

Name of the directory

func (*DirMeta) Size 

func (d *DirMeta) Size() int64

Size of the directory

func (*DirMeta) Sys 

func (d *DirMeta) Sys() interface{}

Sys provides os.FileInfo trapdoor down to undefined behavior

type File 

type File struct {
	// contains filtered or unexported fields
}

File holds the metadata of a FS object

func FileFromOS 

func FileFromOS(path string, uid, gid uint32, info os.FileInfo) *File

FileFromOS creates a file representing an underlying OS file. writes will transition the file contents to a memory buffer.

func (*File) Bytes 

func (f *File) Bytes() []byte

Bytes returns a direct buffer of the contents of the file

func (*File) IsDir 

func (f *File) IsDir() bool

IsDir returns if the file is a directory (no)

func (*File) ModTime 

func (f *File) ModTime() time.Time

ModTime returns when the file was modified

func (*File) Mode 

func (f *File) Mode() os.FileMode

Mode returns the file's mode

func (*File) Name 

func (f *File) Name() string

Name returns the file name

func (*File) Size 

func (f *File) Size() int64

Size returns the file's size

func (*File) Sys 

func (f *File) Sys() interface{}

Sys is a wildcard in the OS interface

type FileContent 

type FileContent interface {
	Size() int64
	io.ReaderAt
	io.WriterAt
}

FileContent represents the actual data of a file.

func MemBufferFrom 

func MemBufferFrom(fc FileContent) FileContent

MemBufferFrom copies a file contents into a memoryContents format where it can be truncated

func NewEmptyFileContents 

func NewEmptyFileContents() FileContent

NewEmptyFileContents creates a new memoryContents buffer

type Placer 

type Placer struct {
	// contains filtered or unexported fields
}

Placer conforms a memphis directory tree to the rio FS interface

func (*Placer) BasePath 

func (p *Placer) BasePath() fs.AbsolutePath

BasePath is the root of this FS - always '/'

func (*Placer) Chmod 

func (p *Placer) Chmod(path fs.RelPath, perms fs.Perms) error

Chmod sets permissions of path

func (*Placer) LStat 

func (p *Placer) LStat(path fs.RelPath) (*fs.Metadata, error)

LStat returns file metadata not following symlinks

func (*Placer) Lchown 

func (p *Placer) Lchown(path fs.RelPath, uid uint32, gid uint32) error

Lchown sets ownership of path w/o following symlinks

func (*Placer) MkdevBlock 

func (p *Placer) MkdevBlock(path fs.RelPath, major int64, minor int64, perms fs.Perms) error

MkdevBlock makes a block device at path

func (*Placer) MkdevChar 

func (p *Placer) MkdevChar(path fs.RelPath, major int64, minor int64, perms fs.Perms) error

MkdevChar makes a character device at path

func (*Placer) Mkdir 

func (p *Placer) Mkdir(path fs.RelPath, perms fs.Perms) error

Mkdir makes a directory at path

func (*Placer) Mkfifo 

func (p *Placer) Mkfifo(path fs.RelPath, perms fs.Perms) error

Mkfifo makes a fifo node at path 

func (p *Placer) Mklink(path fs.RelPath, target string) error

Mklink makes a symlink at path

func (*Placer) OpenFile 

func (p *Placer) OpenFile(path fs.RelPath, flag int, perms fs.Perms) (fs.File, error)

OpenFile attempts to open a file

func (*Placer) ReadDirNames 

func (p *Placer) ReadDirNames(path fs.RelPath) ([]string, error)

ReadDirNames lists files in a directory 

func (p *Placer) Readlink(path fs.RelPath) (target string, isSymlink bool, err error)

Readlink reads a symlink 

func (p *Placer) ResolveLink(symlink string, startingAt fs.RelPath) (fs.RelPath, error)

ResolveLink resolves a symlink

func (*Placer) SetTimesLNano 

func (p *Placer) SetTimesLNano(path fs.RelPath, mtime time.Time, atime time.Time) error

SetTimesLNano sets modification/access times of path

func (*Placer) SetTimesNano 

func (p *Placer) SetTimesNano(path fs.RelPath, mtime time.Time, atime time.Time) error

SetTimesNano sets modification/access times of path

func (*Placer) Stat 

func (p *Placer) Stat(path fs.RelPath) (*fs.Metadata, error)

Stat returns file metadata

type Tree 

type Tree struct {
	// contains filtered or unexported fields
}

Tree represents a directory

func FromOS 

func FromOS(osPath string) *Tree

FromOS creates a memphis instance overlayed on an OS subtree

func New 

func New() *Tree

New creates a new, empty memphis instance

func (*Tree) AsBillyFS 

func (t *Tree) AsBillyFS(euid, egid uint32) *Billy

AsBillyFS provides a billy-comptatible view of the current memphis directory tree

func (*Tree) Create 

func (t *Tree) Create(name string, euid, egid uint32, perm os.FileMode) *File

Create makes a new file in the directory

func (*Tree) CreateDir 

func (t *Tree) CreateDir(name string, euid, egid uint32, perm os.FileMode) *Tree

CreateDir makes a new directory in the directory

func (*Tree) Get 

func (t *Tree) Get(p []string, followSymlinks bool) (*File, *Tree, error)

Get attempts to get a file at a given path.

func (*Tree) WalkDir 

func (t *Tree) WalkDir(p []string) *Tree

WalkDir descends to a given sub directory

type TruncatableContents 

type TruncatableContents interface {
	Truncate(size int64) error
}

TruncatableContents is an optional FileContent interface for efficiency

Source Files

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