Smash key-gen out of processor

Resolves some bad assumptions made regarding keys being unique or not.

processor/key-gen/src/generators.rs

@@ -0,0 +1,38 @@
+use core::any::{TypeId, Any};
+use std::{
+  sync::{LazyLock, Mutex},
+  collections::HashMap,
+};
+
+use dkg::evrf::*;
+
+use serai_validator_sets_primitives::MAX_KEY_SHARES_PER_SET;
+
+/// A cache of the generators used by the eVRF DKG.
+///
+/// This performs a lookup of the Ciphersuite to its generators. Since the Ciphersuite is a
+/// generic, this takes advantage of `Any`. This static is isolated in a module to ensure
+/// correctness can be evaluated solely by reviewing these few lines of code.
+///
+/// This is arguably over-engineered as of right now, as we only need generators for Ristretto
+/// and N::Curve. By having this HashMap, we enable de-duplication of the Ristretto == N::Curve
+/// case, and we automatically support the n-curve case (rather than hard-coding to the 2-curve
+/// case).
+static GENERATORS: LazyLock<Mutex<HashMap<TypeId, &'static (dyn Send + Sync + Any)>>> =
+  LazyLock::new(|| Mutex::new(HashMap::new()));
+
+pub(crate) fn generators<C: EvrfCurve>() -> &'static EvrfGenerators<C> {
+  GENERATORS
+    .lock()
+    .unwrap()
+    .entry(TypeId::of::<C>())
+    .or_insert_with(|| {
+      // If we haven't prior needed generators for this Ciphersuite, generate new ones
+      Box::leak(Box::new(EvrfGenerators::<C>::new(
+        ((MAX_KEY_SHARES_PER_SET * 2 / 3) + 1).try_into().unwrap(),
+        MAX_KEY_SHARES_PER_SET.try_into().unwrap(),
+      )))
+    })
+    .downcast_ref()
+    .unwrap()
+}