Struct WatchManager 

pub struct WatchManager { /* private fields */ }

Manages watch subscriptions for change polling.

Watches are keyed by a UUID watch ID and owned by a specific user. The manager enforces global and per-user watch limits, per-watch entity ID limits, and provides an entity encoding cache for efficient WebSocket server-push serialization.

Implementations

impl WatchManager

pub fn new() -> Self

Create a new empty WatchManager.

pub fn subscribe( &self, username: &str, ids: Vec<String>, graph_version: u64, ) -> Result<String, String>

Subscribe to changes on a set of entity IDs.

Returns the watch ID, or an error if a growth cap would be exceeded.

pub fn poll( &self, watch_id: &str, username: &str, graph: &SharedGraph, ) -> Option<Vec<HDict>>

Poll for changes since the last poll.

Returns the current state of watched entities that have changed, or None if the watch ID is not found or the caller is not the owner.

pub fn unsubscribe(&self, watch_id: &str, username: &str) -> bool

Unsubscribe a watch by ID.

Returns true if the watch existed, was owned by username, and was removed.

pub fn add_ids(&self, watch_id: &str, username: &str, ids: Vec<String>) -> bool

Add entity IDs to an existing watch.

Returns true if the watch exists, is owned by username, and the addition would not exceed the per-watch entity ID limit.

pub fn remove_ids(&self, watch_id: &str, username: &str, ids: &[String]) -> bool

Remove specific entity IDs from an existing watch.

Returns true if the watch exists and is owned by username. If all IDs are removed, the watch remains but with an empty entity set.

pub fn get_ids(&self, watch_id: &str) -> Option<Vec<String>>

Return the list of entity IDs for a given watch.

Returns None if the watch does not exist.

pub fn len(&self) -> usize

Return the number of active watches.

pub fn is_empty(&self) -> bool

Return whether there are no active watches.

pub fn encode_cached( &self, ref_val: &str, graph_version: u64, entity: &HDict, ) -> Value

Encode an entity using the cache. Returns cached value if the entity version hasn’t changed; otherwise encodes and caches the result.

pub fn all_watched_ids(&self) -> HashSet<String>

Get the IDs of all entities watched by any watch, for server-push change detection.

pub fn watches_affected_by( &self, changed_refs: &HashSet<&str>, ) -> Vec<(String, String, Vec<String>)>

Find watches that contain any of the given changed ref_vals. Returns (watch_id, owner, changed_entity_ids) tuples.

Trait Implementations

impl Default for WatchManager

fn default() -> Self

Returns the “default value” for a type.