Struct DiskCache 

pub struct DiskCache { /* private fields */ }

A disk cache is “perferably” a sparse file that allows snapshot blocks to be writen to disk and is checked before trying to downloading a block. The cache uses a i32 (data type that AWS uses to store a block index) index to determine if a give block has already been downloaded. This index is commited to disk every n number of writes (see .with_commit_frequency()).

Implementations

impl DiskCache

pub fn from_path(path: impl AsRef<Path>) -> Result<Self, Error>

pub fn with_commit_frequency(self, commit_frequency: u32) -> Self

pub fn read_block( &mut self, index: i32, block_size: usize, ) -> Result<Option<Vec<u8>>, Error>

Given an index and the block size, read a block from the cache

pub fn write_block(&mut self, index: i32, block: &[u8]) -> Result<bool, Error>

Write a block to the cache. If we have seen this block, ignore it. Return false if it has not been seen before, true if it has

pub fn index_file_location(&self) -> PathBuf

Get the index location for this cache

pub fn size(&self) -> Result<u64, Error>

Get size of the cache file

pub fn set_size(&mut self, length: i64) -> Result<(), Error>

Set the size of the cache file

pub fn commit(&self) -> Result<(), Error>

Commit the index mapping to disk