Nested Filesystem Implementation (vfs_nested)

A virtual filesystem implementation that allows mounting multiple VFS implementations at different path prefixes, creating a unified filesystem view.

Features

• Mount multiple VFS implementations
• Path-based routing to appropriate implementations
• Transparent operation across mounted filesystems
• Hierarchical organization
• Cross-implementation file operations
• Virtual root directory showing mount points

Implementation Details

Structure

vfs_nested/
├── vfsnested.v          # Core implementation
└── nested_test.v        # Implementation tests

Key Components

• NestedVFS: Main implementation struct that manages mounted filesystems
• RootEntry: Special entry type representing the root directory
• MountEntry: Special entry type representing mounted filesystem points

Usage

import vfs
import vfs_nested

fn main() ! {
    mut nested := vfs_nested.new()
    mut local_fs := vfs.new_vfs('local', '/tmp/local')!
    nested.add_vfs('/local', local_fs)!
    nested.file_create('/local/test.txt')!
}

Limitations

• Cannot rename/move files across different implementations
• Symlinks must be contained within a single implementation
• No atomic operations across implementations
• Mount points are fixed after creation

fn new() &NestedVFS

new creates a new NestedVFS instance

fn (self &RootEntry) is_dir() bool

is_dir returns true if the entry is a directory

fn (self &RootEntry) is_file() bool

is_file returns true if the entry is a file

fn (self &RootEntry) is_symlink() bool

is_symlink returns true if the entry is a symlink

struct MountEntry {
pub mut:
	metadata vfs.Metadata
	impl     vfs.VFSImplementation
}

fn (self &MountEntry) is_dir() bool

is_dir returns true if the entry is a directory

fn (self &MountEntry) is_file() bool

is_file returns true if the entry is a file

fn (self &MountEntry) is_symlink() bool

is_symlink returns true if the entry is a symlink

struct NestedEntry {
pub mut:
	original vfs.FSEntry
	prefix   string
}

NestedEntry wraps an FSEntry from a sub VFS and prefixes its path

fn (self &NestedEntry) is_dir() bool

is_dir returns true if the entry is a directory

fn (self &NestedEntry) is_file() bool

is_file returns true if the entry is a file

fn (self &NestedEntry) is_symlink() bool

is_symlink returns true if the entry is a symlink

struct NestedVFS {
mut:
	vfs_map map[string]vfs.VFSImplementation @[skip] // Map of path prefixes to VFS implementations
}

NestedVFS represents a VFS that can contain multiple nested VFS instances

fn (mut self NestedVFS) add_vfs(prefix string, impl vfs.VFSImplementation) !

add_vfs adds a new VFS implementation at the specified path prefix

fn (mut self NestedVFS) root_get() !vfs.FSEntry

Implementation of VFSImplementation interface

fn (mut self NestedVFS) delete(path string) !

fn (mut self NestedVFS) link_delete(path string) !

fn (mut self NestedVFS) file_create(path string) !vfs.FSEntry

fn (mut self NestedVFS) file_read(path string) ![]u8

fn (mut self NestedVFS) file_write(path string, data []u8) !

fn (mut self NestedVFS) file_delete(path string) !

fn (mut self NestedVFS) dir_create(path string) !vfs.FSEntry

fn (mut self NestedVFS) dir_list(path string) ![]vfs.FSEntry

fn (mut self NestedVFS) dir_delete(path string) !

fn (mut self NestedVFS) exists(path string) bool

fn (mut self NestedVFS) get(path string) !vfs.FSEntry

fn (mut self NestedVFS) rename(old_path string, new_path string) !vfs.FSEntry

fn (mut self NestedVFS) copy(src_path string, dst_path string) !vfs.FSEntry

fn (mut self NestedVFS) move(src_path string, dst_path string) !vfs.FSEntry

fn (mut self NestedVFS) link_create(target_path string, link_path string) !vfs.FSEntry

fn (mut self NestedVFS) link_read(path string) !string

fn (mut self NestedVFS) destroy() !