Struct BlockReader 

pub struct BlockReader { /* private fields */ }

A builder for a fixed block size file reader.

Implementations

impl BlockReader

pub fn new<P>(fname: P, block_size: usize) -> Self

where P: AsRef<Path>,

Construct a new BlockReader builder.

Defaults to a queue limit of 2 blocks.

Panics

The block_size must be greater than zero.

pub fn queue_size(self, len: usize) -> Self

Set the queue size, in number of blocks.

This configures how many blocks can be “in-flight”.

Panics

The len parameter mus be greater than zero.

impl BlockReader

pub fn proc<F, E>(self, f: F) -> Result<(), E>

where F: FnMut(&[u8]) -> ControlFlow<E>, E: From<Error>,

Read file block-by-block and call a closure to process each block.

There’s an assumption that the file’s size will not change: Once the end of the file has been reached, the function will return.

Internals

This function does not carry any blocks in-flight apart from the block currently being processed. It is intended to be used when the closure returns quickly.

Errors

pub fn proc_thrd<F, E>(self, f: F) -> Result<(), E>

where F: FnMut(Vec<u8>) -> ControlFlow<E>, E: From<Error> + Send + 'static,

Read file block-by-block on a background thread and pass each block via a channel to a closure.

This method should be preferred over BlockReader::proc() if the closure needs ownership of the blocks and its processing is non-trivial (i.e. the background thread can pre-load the next block).

Errors

Returns a caller-defined error E which must be convertible from a std::io::Error. If the

pub fn channel( self, ) -> Result<(Receiver<Result<Vec<u8>, Error>>, JoinHandle<()>), Error>

Open a file and return a channel receiver end-point that will return the file’s contents block-by-block.

Once the file’s end-of-file has been reached, the transmitting end-point will be dropped, which will cause the receiver end-point to fail once the remaining blocks have been read.

Errors

pub fn try_iter(self) -> Result<BlockIter, Error>

Return an Iterator which yields the file’s blocks.

Errors