Struct KvBackend 

pub struct KvBackend { /* private fields */ }

In-memory KV backend, namespaced by plugin name. The outer map is keyed by plugin name; the inner map by user-supplied key.

Four optional caps bound how much a caller (plugin or the /admin/kv endpoint) can store; 0 on any of them means “unlimited”. new() / Default leave them all at 0 so existing callers and tests keep the historical unbounded behaviour; production wires real values via KvBackend::with_limits.

Implementations

impl KvBackend

pub fn new() -> Self

pub fn with_limits( max_value_bytes: usize, max_keys_per_plugin: usize, max_plugins: usize, max_total_bytes: usize, ) -> Self

Construct with explicit caps. 0 on any field = unlimited.

pub fn max_value_bytes(&self) -> usize

The configured single key/value byte cap (0 = unlimited). Lets a caller (e.g. the /admin/kv PUT handler) fast-reject an oversized body before allocating an owned copy of it.

pub fn get(&self, plugin: &str, key: &[u8]) -> Option<Vec<u8>>

Read a value. None if missing.

pub fn set(&self, plugin: &str, key: Vec<u8>, value: Vec<u8>) -> bool

Insert / overwrite. Returns false (and leaves the store untouched) when a configured cap would be exceeded:

• the key OR value length exceeds max_value_bytes, or
• creating a NEW plugin namespace would push the store past max_plugins, or
• inserting a NEW key would push the namespace past max_keys_per_plugin, or
• the resulting total_bytes would exceed max_total_bytes.

Overwriting an existing key (or writing another key into an already-present namespace) never fails the key-count or namespace cap. Every cap is checked BEFORE any mutation, so a rejected write leaves the store and the byte counter unchanged.

pub fn delete(&self, plugin: &str, key: &[u8])

Delete; idempotent. Drops the plugin’s inner map and its outer-map slot once the namespace becomes empty, so a delete-heavy caller actually reclaims memory instead of leaving zombie namespaces behind — this also keeps the max_plugins namespace count honest (a fully-drained namespace frees a slot). The reclaimed key/value/namespace bytes are subtracted from the total_bytes counter so the max_total_bytes cap tracks the live footprint exactly.

pub fn len(&self, plugin: &str) -> usize

Returns the number of keys in the plugin’s namespace. Useful for tests and the admin endpoint.

pub fn list_keys(&self, plugin: &str, prefix: &[u8]) -> Vec<String>

List keys (lossy UTF-8) in a plugin’s namespace, optionally filtered by a byte prefix (pass b"" for all keys). Backs the GET /admin/kv/<plugin>/ list endpoint.

Trait Implementations

impl Clone for KvBackend

fn clone(&self) -> KvBackend

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for KvBackend

fn default() -> KvBackend

Returns the “default value” for a type.