Trait Platform 

pub trait Platform {
    // Required methods
    fn filesystem_facts(
        &self,
        path: &Path,
    ) -> Result<(FilesystemKind, u64), PrimitiveError>;
    fn is_subvolume_root(&self, path: &Path) -> Result<bool, PrimitiveError>;
    fn create_subvolume(&self, path: &Path) -> Result<(), PrimitiveError>;
    fn destroy_subvolume(&self, path: &Path) -> Result<(), PrimitiveError>;
    fn removal_allowed(&self, path: &Path) -> bool;
    fn is_mount_point(&self, path: &Path) -> bool;
    fn clone_file(
        &self,
        source: &File,
        destination: &File,
        path: &Path,
    ) -> Result<(), PrimitiveError>;
    fn exchange(
        &self,
        first: &Path,
        second: &Path,
    ) -> Result<(), PrimitiveError>;

    // Provided method
    fn hard_link(&self, existing: &Path, new: &Path) -> Result<()> { ... }
}

What: The operations of the migration that depend on the kind of filesystem. &self borrows the platform read-only so one platform serves a whole run; dyn Platform is how a caller holds “any implementation” (TS interface). Why: See the module description.

In TS you’d write (pseudocode):

interface Platform { ... }

Required Methods

fn filesystem_facts( &self, path: &Path, ) -> Result<(FilesystemKind, u64), PrimitiveError>

The filesystem kind holding path and the bytes free there.

fn is_subvolume_root(&self, path: &Path) -> Result<bool, PrimitiveError>

Whether path is the root of a subvolume.

fn create_subvolume(&self, path: &Path) -> Result<(), PrimitiveError>

Create an empty subvolume at path.

fn destroy_subvolume(&self, path: &Path) -> Result<(), PrimitiveError>

Destroy the subvolume at path with the kernel call (the caller falls back to emptying and rmdir).

fn removal_allowed(&self, path: &Path) -> bool

Whether an unprivileged subvolume destroy is allowed on the mount holding path.

fn is_mount_point(&self, path: &Path) -> bool

Whether path is itself a mount point (a mount point cannot be exchanged).

fn clone_file( &self, source: &File, destination: &File, path: &Path, ) -> Result<(), PrimitiveError>

Clone a whole file’s data blocks.

fn exchange(&self, first: &Path, second: &Path) -> Result<(), PrimitiveError>

Swap two paths atomically.

Provided Methods

fn hard_link(&self, existing: &Path, new: &Path) -> Result<()>

Make new another name of the file existing; fails with EXDEV where the two sit in different subvolumes.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl Platform for LinuxPlatform

The primitives, called as they are.