Struct CacheReader 

pub struct CacheReader { /* private fields */ }

Reads events from a binary columnar cache file.

The reader validates magic bytes, version, and CRC on open, then decodes columns using the ColumnCodec traits to reconstruct Event structs.

Example

use bones_core::cache::reader::CacheReader;

let reader = CacheReader::open("path/to/events.bin").unwrap();
println!("cache contains {} events", reader.event_count());
let events = reader.read_all().unwrap();

Implementations

impl CacheReader

pub fn open(path: impl AsRef<Path>) -> Result<Self, CacheReaderError>

Open and validate a cache file.

Reads the file into memory, validates the magic bytes, format version, and CRC-64 checksum. Returns an error if any validation step fails.

Errors

Returns CacheError if the file cannot be read, or if magic, version, or CRC validation fails.

pub fn from_bytes(data: Vec<u8>) -> Result<Self, CacheReaderError>

Create a reader from raw bytes (useful for testing).

Errors

Returns CacheError if validation fails.

pub fn event_count(&self) -> usize

Return the number of events (rows) in the cache file without decoding.

pub const fn header(&self) -> &CacheHeader

Return a reference to the cache header.

pub fn read_all(&self) -> Result<Vec<Event>, CacheReaderError>

Decode all events from the cache.

Note: The event_hash field will be empty on reconstructed events. Callers needing hashes must recompute them.

Errors

Returns CacheReaderError if column decoding fails.

pub fn read_range( &self, start: usize, count: usize, ) -> Result<Vec<Event>, CacheReaderError>

Decode a range of events from the cache.

Returns events [start .. start + count], clamped to the actual row count. If start >= event_count(), returns an empty Vec.

Implementation note: The current columnar format requires decoding all rows and then slicing. A future optimisation could add per-column offset tables for truly random access.

Errors

Returns CacheReaderError if column decoding fails.

pub const fn created_at_us(&self) -> u64

Return the creation timestamp of the cache file (µs since epoch).

pub const fn data_crc64(&self) -> u64

Return the stored CRC-64 checksum of the column data.

pub const fn file_size(&self) -> usize

Return the total size of the raw cache data in bytes.

Trait Implementations

impl Clone for CacheReader

fn clone(&self) -> CacheReader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CacheReader

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

Formats the value using the given formatter.