Struct FileWriters 

pub struct FileWriters { /* private fields */ }

Open write handles keyed by file id.

Handles are opened on the first chunk that arrives for a file rather than up front: a manifest may name a million files, and a million open descriptors is not a thing we can ask the OS for.

Implementations

impl FileWriters

pub fn new() -> Self

pub fn get_or_open<F>(&self, file_id: u32, make: F) -> Result<Arc<WriteHandle>>

where F: FnOnce() -> Result<WriteHandle>,

Fetch the handle for file_id, opening it with make if absent.

make runs at most once per file, even when every worker hits the same file’s first chunk simultaneously. That is not just an efficiency point: opening a destination preallocates it, so letting several racing callers each open the same file reserved the file’s full size several times over and could exhaust the disk on a large transfer.

The lock taken during make is per file, so opening one file never blocks writers on another.

pub fn take(&self, file_id: u32) -> Option<Arc<WriteHandle>>

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn discard_all(&self)

Drop every handle, deleting partial files. Used on unrecoverable abort.

Trait Implementations

impl Default for FileWriters

fn default() -> Self

Returns the “default value” for a type.