fusefs

package
v0.2.2 Latest Latest
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 Go to latest Published: Apr 13, 2026 License: MIT Imports: 7 Imported by: 0

Documentation

Overview

Package fusefs provides a read-only filesystem interface over pxar archives, compatible with hanwen/go-fuse's InodeEmbedder and Inode interfaces.

This package does NOT import go-fuse. It defines compatible interfaces (FileSystem, Attr, DirEntry) so callers can wrap them into a go-fuse FileSystem without the library requiring the dependency.

Basic Usage

Open a pxar archive and create a Session: 

f, err := os.Open("backup.pxar")
defer f.Close()
fi, _ := f.Stat()

sess, err := fusefs.NewSession(f, fi.Size())
if err != nil {
    log.Fatal(err)
}
defer sess.Close()

Filesystem Operations

Session implements the FileSystem interface: 

// Look up a file in a directory
inode, attr, err := sess.Lookup(fusefs.RootInode, "example.txt")

// Read file data
sess.Open(inode, 0)
buf := make([]byte, attr.Size)
n, err := sess.Read(inode, buf, 0)

// List directory
entries, err := sess.Readdir(fusefs.RootInode, 0)

// Read symlink target
target, err := sess.Readlink(symlinkInode)

Inode Model

The root directory uses inode 1 (RootInode). Non-directory inodes have the NonDirBit (bit 63) set. Use IsDirInode to distinguish: 

fusefs.IsDirInode(inode) // true if directory

Nodes track entry ranges and optional content ranges for file data access. Reference counting is handled automatically via Ref/Unref/Forget.

Package fusefs provides a read-only filesystem interface over pxar archives, compatible with hanwen/go-fuse's InodeEmbedder and Inode interfaces.

This package does NOT import go-fuse — it defines compatible interfaces so callers can wrap them into a go-fuse FileSystem without the library needing the dependency.

Index

Constants

View Source 
const (
	// RootInode is the inode number for the root directory.
	RootInode = 1

	// NonDirBit is set in the high bit of inodes for non-directory entries.
	NonDirBit uint64 = 1 << 63
)

Variables

This section is empty.

Functions

func IsDirInode 

func IsDirInode(inode uint64) bool

IsDirInode returns true if the inode represents a directory.

Types

type Attr 

type Attr struct {
	Ino       uint64
	Size      uint64
	Blocks    uint64
	Atime     uint64
	Mtime     uint64
	Ctime     uint64
	Atimensec uint32
	Mtimensec uint32
	Ctimensec uint32
	Mode      uint32
	Nlink     uint32
	Uid       uint32
	Gid       uint32
	Rdev      uint32
	Blksize   uint32
}

Attr represents file metadata, compatible with go-fuse's fuse.Attr.

func StatToAttr 

func StatToAttr(inode uint64, stat format.Stat, fileSize uint64) Attr

StatToAttr converts pxar metadata to FUSE Attr.

type ContentRange 

type ContentRange struct {
	Offset uint64
	Size   uint64
}

ContentRange describes where file content lives in the archive.

type DirEntry 

type DirEntry struct {
	Ino  uint64
	Mode uint32
	Name string
}

DirEntry is a directory entry, compatible with go-fuse's fuse.DirEntry.

type DirEntryIndex 

type DirEntryIndex struct {
	DirEntry
	Offset uint64
}

DirEntryIndex adds an offset to DirEntry for readdir pagination.

type EntryRangeInfo 

type EntryRangeInfo struct {
	Start uint64
	End   uint64
}

EntryRangeInfo describes where an entry lives in the archive.

type FileSystem 

type FileSystem interface {
	// Lookup finds a child entry by name in the given parent directory inode.
	Lookup(parentInode uint64, name string) (inode uint64, attr Attr, err error)

	// Getattr returns the attributes for the given inode.
	Getattr(inode uint64) (Attr, error)

	// Readdir returns directory entries starting at the given offset.
	// Returns entries and the next offset. An empty slice signals end-of-directory.
	Readdir(inode uint64, offset uint64) ([]DirEntryIndex, error)

	// Open informs the kernel that the file is being opened.
	Open(inode uint64, flags uint32) error

	// Read reads data from a file inode at the given offset.
	// FUSE requires no short reads (except at EOF).
	Read(inode uint64, dest []byte, offset int64) (int, error)

	// Readlink returns the symlink target for the given inode.
	Readlink(inode uint64) (string, error)

	// ListXAttr returns all extended attribute names for the given inode.
	ListXAttr(inode uint64) ([]string, error)

	// GetXAttr returns the value of a specific extended attribute.
	GetXAttr(inode uint64, attr string) ([]byte, error)

	// Forget decrements the reference count for an inode.
	Forget(inode uint64, count uint64)

	// Statfs returns filesystem statistics.
	Statfs() (syscall.Statfs_t, error)

	// Access checks file accessibility.
	Access(inode uint64, mask uint32) error

	// Release is called when a file is closed.
	Release(inode uint64)
}

FileSystem is the interface that maps pxar archive entries to FUSE operations. It is compatible with hanwen/go-fuse's InodeEmbedder and RawFileSystem patterns.

type Node 

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

Node holds cached metadata for a filesystem entry.

func (*Node) Cache 

func (n *Node) Cache() (format.Stat, uint64, bool)

Cache returns cached stat metadata.

func (*Node) Content 

func (n *Node) Content() (offset, size uint64, ok bool)

Content returns the content offset and size.

func (*Node) EntryRange 

func (n *Node) EntryRange() (start, end uint64)

EntryRange returns the entry's byte range in the archive.

func (*Node) Inode 

func (n *Node) Inode() uint64

Inode returns the node's inode number.

func (*Node) Parent 

func (n *Node) Parent() uint64

Parent returns the parent inode.

func (*Node) Ref 

func (n *Node) Ref() bool

Ref increments the reference count. Returns false if the node is already dead.

func (*Node) SetCache 

func (n *Node) SetCache(stat format.Stat, fileSize uint64)

SetCache stores cached stat metadata.

func (*Node) SetContent 

func (n *Node) SetContent(offset, size uint64)

SetContent sets the file content location in the archive.

func (*Node) Unref 

func (n *Node) Unref(count uint64) bool

Unref decrements the reference count. Returns true if the node should be removed.

type ReaderAt 

type ReaderAt interface {
	ReadAt(p []byte, off int64) (n int, err error)
}

ReaderAt is a minimal read interface (io.ReaderAt subset).

type Session 

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

Session implements FileSystem over a pxar archive, providing FUSE-compatible operations without importing go-fuse directly.

func NewSession 

func NewSession(r io.ReadSeeker, size int64) (*Session, error)

NewSession creates a new FUSE filesystem session over a pxar archive.

func (*Session) Access 

func (s *Session) Access(inode uint64, mask uint32) error

Access checks file accessibility (always allowed for read-only).

func (*Session) Close 

func (s *Session) Close() error

Close releases resources held by the session.

func (*Session) Forget 

func (s *Session) Forget(inode uint64, count uint64)

Forget decrements the reference count for an inode.

func (*Session) GetXAttr 

func (s *Session) GetXAttr(inode uint64, attr string) ([]byte, error)

GetXAttr returns the value of a specific extended attribute.

func (*Session) Getattr 

func (s *Session) Getattr(inode uint64) (Attr, error)

Getattr returns attributes for the given inode.

func (*Session) ListXAttr 

func (s *Session) ListXAttr(inode uint64) ([]string, error)

ListXAttr returns extended attribute names.

func (*Session) Lookup 

func (s *Session) Lookup(parentInode uint64, name string) (uint64, Attr, error)

Lookup finds a child entry by name in the given parent directory.

func (*Session) Open 

func (s *Session) Open(inode uint64, flags uint32) error

Open is a no-op for read-only archives.

func (*Session) Read 

func (s *Session) Read(inode uint64, dest []byte, offset int64) (int, error)

Read reads data from a file. FUSE requires no short reads except at EOF.

func (*Session) Readdir 

func (s *Session) Readdir(inode uint64, offset uint64) ([]DirEntryIndex, error)

Readdir returns directory entries starting at the given offset. 

func (s *Session) Readlink(inode uint64) (string, error)

Readlink returns the symlink target.

func (*Session) Release 

func (s *Session) Release(inode uint64)

Release is a no-op.

func (*Session) Statfs 

func (s *Session) Statfs() (syscall.Statfs_t, error)

Statfs returns filesystem statistics.

type XAttr 

type XAttr struct {
	Name  string
	Value []byte
}

XAttr represents an extended attribute.

Source Files

View all Source files

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