Struct LocalDatabase 

pub struct LocalDatabase<T> { /* private fields */ }

A local database for storing key-value pairs.

The database is stored in a JSON file, which is updated every time a key-value pair is added, updated, or removed. Writes are atomic (write to temporary file, then rename) to prevent corruption.

Example

use blueprint_store_local_database::LocalDatabase;

let db = LocalDatabase::<u64>::open("data.json")?;

db.set("key", 42)?;
assert_eq!(db.get("key")?, Some(42));

Implementations

impl<T> LocalDatabase<T>

where T: Serialize + DeserializeOwned + Clone,

pub fn open<P: AsRef<Path>>(path: P) -> Result<Self, Error>

Reads a LocalDatabase from the given path.

If the file does not exist, an empty database is created.

Examples

use blueprint_store_local_database::LocalDatabase;

let db = LocalDatabase::<u64>::open("data.json")?;
assert!(db.is_empty()?);

Errors

• The parent of path is not a directory
• Unable to write to path

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

Returns the number of key-value pairs in the database.

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

Checks if the database is empty.

pub fn set(&self, key: &str, value: T) -> Result<(), Error>

Adds or updates a key-value pair in the database.

Errors

• Unable to serialize the data
• Unable to write to disk

pub fn get(&self, key: &str) -> Result<Option<T>, Error>

Retrieves a value associated with the given key.

pub fn remove(&self, key: &str) -> Result<Option<T>, Error>

Removes a key-value pair from the database.

Returns the removed value if the key existed.

pub fn values(&self) -> Result<Vec<T>, Error>

Returns a clone of all values in the database.

pub fn entries(&self) -> Result<Vec<(String, T)>, Error>

Returns a clone of all key-value pairs in the database.

pub fn find<F>(&self, predicate: F) -> Result<Option<T>, Error>

where F: Fn(&T) -> bool,

Finds the first value matching a predicate.

pub fn update<F>(&self, key: &str, f: F) -> Result<bool, Error>

where F: FnOnce(&mut T),

Atomically gets a value by key, applies a mutation, and flushes.

Returns true if the key was found and updated.

pub fn replace(&self, new_data: HashMap<String, T>) -> Result<(), Error>

Replaces the entire database contents with a new map.

pub fn contains_key(&self, key: &str) -> Result<bool, Error>

Checks if a key exists in the database.

Trait Implementations

impl<T: Debug> Debug for LocalDatabase<T>

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

Formats the value using the given formatter.