Struct rocket_file_cache::CacheBuilder

pub struct CacheBuilder { /* fields omitted */ }

A builder for Caches.

Methods

impl CacheBuilder

fn new(size_limit: usize) -> CacheBuilder

Create a new CacheBuilder.

fn concurrency<'a>(&'a mut self, concurrency: u16) -> &mut Self

Sets the concurrency setting of the concurrent hashmap backing the cache. A higher concurrency setting allows more threads to access the hashmap at the expense of more memory use. The default is 16.

fn priority_function<'a>(
    &'a mut self,
    priority_function: fn(_: usize, _: usize) -> usize
) -> &mut Self

Override the default priority function used for determining if the cache should hold a file. By default a score is calculated using the square root of the size of a file, times the number of times it was accessed. Files with higher priority scores will be kept in the cache when files with lower scores are added. If there isn't room in the cache for two files, the one with the lower score will be removed / won't be added.

The priority function should be kept simple, as it is calculated on every file in the cache every time a new file is attempted to be added.

use rocket_file_cache::Cache;
use rocket_file_cache::CacheBuilder;
let cache: Cache = CacheBuilder::new(1024 * 1024 * 50) // 50 MB cache
    .priority_function(|access_count, size| {
        access_count * access_count * size
    })
    .build()
    .unwrap();

fn min_file_size<'a>(&'a mut self, min_size: usize) -> &mut Self

Set the minimum size in bytes for files that can be stored in the cache

fn max_file_size<'a>(&'a mut self, max_size: usize) -> &mut Self

Set the maximum size in bytes for files that can be stored in the cache

fn build(&self) -> Result<Cache, CacheBuildError>

Finalize the cache.

Example

use rocket_file_cache::Cache;
use rocket_file_cache::CacheBuilder;

let cache: Cache = CacheBuilder::new(1024 * 1024 * 50) // 50 MB cache
    .min_file_size(1024 * 4) // Don't store files smaller than 4 KB
    .max_file_size(1024 * 1024 * 6) // Don't store files larger than 6 MB
    .build()
    .unwrap();

Trait Implementations

impl Debug for CacheBuilder

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.