Struct LruHeaderCache 

pub struct LruHeaderCache { /* private fields */ }

LRU (Least Recently Used) cache for article metadata

Implements a simple LRU cache using a HashMap and access ordering. When the cache is full, the least recently accessed entry is evicted.

Example

use nntp_rs::cache::{HeaderCache, LruHeaderCache};
use nntp_rs::XoverEntry;

let mut cache = LruHeaderCache::new(2); // Max 2 entries

let entry1 = XoverEntry {
    article_number: 1,
    subject: "First".to_string(),
    author: "author1@example.com".to_string(),
    date: "2024-01-01".to_string(),
    message_id: "<1@example.com>".to_string(),
    references: "".to_string(),
    bytes: 100,
    lines: 10,
};

let entry2 = XoverEntry {
    article_number: 2,
    subject: "Second".to_string(),
    author: "author2@example.com".to_string(),
    date: "2024-01-02".to_string(),
    message_id: "<2@example.com>".to_string(),
    references: "".to_string(),
    bytes: 200,
    lines: 20,
    };

cache.put(1, entry1);
cache.put(2, entry2);
assert_eq!(cache.len(), 2);

// Access entry 1 to make it recently used
cache.get(&1);

// Adding a third entry will evict entry 2 (least recently used)
let entry3 = XoverEntry {
    article_number: 3,
    subject: "Third".to_string(),
    author: "author3@example.com".to_string(),
    date: "2024-01-03".to_string(),
    message_id: "<3@example.com>".to_string(),
    references: "".to_string(),
    bytes: 300,
    lines: 30,
};
cache.put(3, entry3);

assert_eq!(cache.len(), 2);
assert!(cache.contains(&1)); // Still cached
assert!(!cache.contains(&2)); // Evicted
assert!(cache.contains(&3)); // Newly added

Implementations

impl LruHeaderCache

pub fn new(max_size: usize) -> Self

Create a new LRU cache with the specified maximum size

Arguments

• max_size - Maximum number of entries to cache (must be > 0)

Panics

Panics if max_size is 0

Example

use nntp_rs::cache::{LruHeaderCache, HeaderCache};

let cache = LruHeaderCache::new(1000);
assert_eq!(cache.capacity(), 1000);
assert!(cache.is_empty());

Trait Implementations

impl Clone for LruHeaderCache

fn clone(&self) -> LruHeaderCache

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LruHeaderCache

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl HeaderCache for LruHeaderCache

fn put(&mut self, article_number: u64, entry: XoverEntry)

Store an article’s overview data

fn get(&mut self, article_number: &u64) -> Option<&XoverEntry>

Retrieve an article’s overview data

fn contains(&self, article_number: &u64) -> bool

Check if an article exists in cache

fn remove(&mut self, article_number: &u64) -> Option<XoverEntry>

Remove an article from cache

fn clear(&mut self)

Clear all cached entries

fn len(&self) -> usize

Get the number of cached entries

fn capacity(&self) -> usize

Get the maximum cache size

fn is_empty(&self) -> bool

Check if cache is empty