"Self updating structs" API improvements (#467)

This PR slightly improves the ergonomics of working with self-updating
structs, by making the changes as documented in #466.

src/gateway/handle.rs

@@ -40,10 +40,19 @@ impl GatewayHandle {
             .unwrap();
     }
 
+    /// Recursively observes a [`Shared`] object, by making sure all [`Composite `] fields within
+    /// that object and its children are being watched.
+    ///
+    /// Observing means, that if new information arrives about the observed object or its children,
+    /// the object automatically gets updated, without you needing to request new information about
+    /// the object in question from the API, which is expensive and can lead to rate limiting.
+    ///
+    /// The [`Shared`] object returned by this method points to a different object than the one
+    /// being supplied as a &self function argument.
     pub async fn observe<T: Updateable + Clone + Debug + Composite<T>>(
         &self,
-        object: Arc<RwLock<T>>,
+        object: Shared<T>,
-    ) -> Arc<RwLock<T>> {
+    ) -> Shared<T> {
         let mut store = self.store.lock().await;
         let id = object.read().unwrap().id();
         if let Some(channel) = store.get(&id) {
@@ -84,7 +93,7 @@ impl GatewayHandle {
     /// with all of its observable fields being observed.
     pub async fn observe_and_into_inner<T: Updateable + Clone + Debug + Composite<T>>(
         &self,
-        object: Arc<RwLock<T>>,
+        object: Shared<T>,
     ) -> T {
         let channel = self.observe(object.clone()).await;
         let object = channel.read().unwrap().clone();

src/gateway/mod.rs

@@ -122,3 +122,11 @@ impl<T: WebSocketEvent> GatewayEvent<T> {
         }
     }
 }
+
+/// A type alias for [`Arc<RwLock<T>>`], used to make the public facing API concerned with
+/// Composite structs more ergonomic.
+/// ## Note
+///
+/// While `T` does not have to implement `Composite` to be used with `Shared`,
+/// the primary use of `Shared` is with types that implement `Composite`.
+pub type Shared<T> = Arc<RwLock<T>>;

src/types/entities/mod.rs

@@ -23,6 +23,8 @@ pub use user_settings::*;
 pub use voice_state::*;
 pub use webhook::*;
 
+use crate::gateway::Shared;
+
 #[cfg(feature = "client")]
 use crate::gateway::Updateable;
 
@@ -69,9 +71,9 @@ pub trait Composite<T: Updateable + Clone + Debug> {
     async fn watch_whole(self, gateway: &GatewayHandle) -> Self;
 
     async fn option_observe_fn(
-        value: Option<Arc<RwLock<T>>>,
+        value: Option<Shared<T>>,
         gateway: &GatewayHandle,
-    ) -> Option<Arc<RwLock<T>>>
+    ) -> Option<Shared<T>>
     where
         T: Composite<T> + Debug,
     {
@@ -84,9 +86,9 @@ pub trait Composite<T: Updateable + Clone + Debug> {
     }
 
     async fn option_vec_observe_fn(
-        value: Option<Vec<Arc<RwLock<T>>>>,
+        value: Option<Vec<Shared<T>>>,
         gateway: &GatewayHandle,
-    ) -> Option<Vec<Arc<RwLock<T>>>>
+    ) -> Option<Vec<Shared<T>>>
     where
         T: Composite<T>,
     {
@@ -101,17 +103,14 @@ pub trait Composite<T: Updateable + Clone + Debug> {
         }
     }
 
-    async fn value_observe_fn(value: Arc<RwLock<T>>, gateway: &GatewayHandle) -> Arc<RwLock<T>>
+    async fn value_observe_fn(value: Shared<T>, gateway: &GatewayHandle) -> Shared<T>
     where
         T: Composite<T>,
     {
         gateway.observe(value).await
     }
 
-    async fn vec_observe_fn(
+    async fn vec_observe_fn(value: Vec<Shared<T>>, gateway: &GatewayHandle) -> Vec<Shared<T>>
-        value: Vec<Arc<RwLock<T>>>,
-        gateway: &GatewayHandle,
-    ) -> Vec<Arc<RwLock<T>>>
     where
         T: Composite<T>,
     {
@@ -122,3 +121,19 @@ pub trait Composite<T: Updateable + Clone + Debug> {
         vec
     }
 }
+
+pub trait IntoShared {
+    /// Uses [`Shared`] to provide an ergonomic alternative to `Arc::new(RwLock::new(obj))`.
+    ///
+    /// [`Shared<Self>`] can then be observed using the [`Gateway`], turning the underlying
+    /// `dyn Composite<Self>` into a self-updating struct, which is a tracked variant of a chorus
+    /// entity struct, updating its' held information when new information concerning itself arrives
+    /// over the [`Gateway`] connection, reducing the need for expensive network-API calls.
+    fn into_shared(self) -> Shared<Self>;
+}
+
+impl<T: Sized> IntoShared for T {
+    fn into_shared(self) -> Shared<Self> {
+        Arc::new(RwLock::new(self))
+    }
+}

tests/common/mod.rs

@@ -1,6 +1,5 @@
-use std::sync::{Arc, RwLock};
+use chorus::gateway::{Gateway, Shared};
-
+use chorus::types::IntoShared;
-use chorus::gateway::Gateway;
 use chorus::{
     instance::{ChorusUser, Instance},
     types::{
@@ -16,9 +15,9 @@ pub(crate) struct TestBundle {
     pub urls: UrlBundle,
     pub user: ChorusUser,
     pub instance: Instance,
-    pub guild: Arc<RwLock<Guild>>,
+    pub guild: Shared<Guild>,
-    pub role: Arc<RwLock<RoleObject>>,
+    pub role: Shared<RoleObject>,
-    pub channel: Arc<RwLock<Channel>>,
+    pub channel: Shared<Channel>,
 }
 
 #[allow(unused)]
@@ -119,9 +118,9 @@ pub(crate) async fn setup() -> TestBundle {
         urls,
         user,
         instance,
-        guild: Arc::new(RwLock::new(guild)),
+        guild: guild.into_shared(),
-        role: Arc::new(RwLock::new(role)),
+        role: role.into_shared(),
-        channel: Arc::new(RwLock::new(channel)),
+        channel: channel.into_shared(),
     }
 }
 

tests/gateway.rs

@@ -1,10 +1,8 @@
 mod common;
 
-use std::sync::{Arc, RwLock};
-
 use chorus::errors::GatewayError;
 use chorus::gateway::*;
-use chorus::types::{self, ChannelModifySchema, RoleCreateModifySchema, RoleObject};
+use chorus::types::{self, ChannelModifySchema, IntoShared, RoleCreateModifySchema, RoleObject};
 #[cfg(target_arch = "wasm32")]
 use wasm_bindgen_test::*;
 #[cfg(target_arch = "wasm32")]
@@ -100,7 +98,7 @@ async fn test_recursive_self_updating_structs() {
     bundle
         .user
         .gateway
-        .observe(Arc::new(RwLock::new(role.clone())))
+        .observe(role.clone().into_shared())
         .await;
     // Update Guild and check for Guild
     let inner_guild = guild.read().unwrap().clone();
@@ -113,7 +111,7 @@ async fn test_recursive_self_updating_structs() {
     let role_inner = bundle
         .user
         .gateway
-        .observe_and_into_inner(Arc::new(RwLock::new(role.clone())))
+        .observe_and_into_inner(role.clone().into_shared())
         .await;
     assert_eq!(role_inner.name, "yippieee");
     // Check if the change propagated