flash-kv 0.2.1

A simple k/v store API inspired by bitcask
Documentation 
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pub mod bptree;
pub mod btree;
pub mod skiplist;

use std::path::PathBuf;

use bytes::Bytes;

use crate::{
  data::log_record::LogRecordPos,
  errors::Result,
  option::{IndexType, IteratorOptions},
};

// Abstract interface specifies methods for interchangeable indexing data structures
pub trait Indexer: Sync + Send {
  /// Store key's position into indexer
  fn put(&self, key: Vec<u8>, pos: LogRecordPos) -> Option<LogRecordPos>;

  /// Retrieve key's position
  fn get(&self, key: Vec<u8>) -> Option<LogRecordPos>;

  /// Delete the position in indexer by key
  fn delete(&self, key: Vec<u8>) -> Option<LogRecordPos>;

  /// List all keys in the indexer
  fn list_keys(&self) -> Result<Vec<Bytes>>;

  /// Create an iterator for the indexer
  fn iterator(&self, options: IteratorOptions) -> Box<dyn IndexIterator>;
}

pub fn new_indexer(index_type: &IndexType, dir_path: &PathBuf) -> Box<dyn Indexer> {
  match *index_type {
    IndexType::BTree => Box::new(btree::BTree::new()),
    IndexType::SkipList => Box::new(skiplist::SkipList::new()),
    IndexType::BPlusTree => Box::new(bptree::BPlusTree::new(dir_path)),
  }
}

// Abstract interface specifies methods for interchangeable index iterators
pub trait IndexIterator: Sync + Send {
  // `Rewind` go back to the beginning of the iterator
  fn rewind(&mut self);

  // `Seek` search for the first entry with a key greater than or equal to the given key
  fn seek(&mut self, key: Vec<u8>);

  // `Next` move to the next entry, when the iterator is exhausted, return None
  fn next(&mut self) -> Option<(&Vec<u8>, &LogRecordPos)>;
}