Refactor - move tree initializer to its own module.

src/database/mod.rs

@@ -6,6 +6,7 @@
 
 use std::cmp::Ordering;
 use std::ops::Deref;
+use std::sync::Arc;
 
 use anyhow::{anyhow, Context, Error as ErrReport};
 use sqlx::migrate::{Migrate, MigrateDatabase, Migrator};
@@ -29,6 +30,8 @@ pub struct Database {
     pub pool: Pool<Postgres>,
 }
 
+pub type SharedDatabase = Arc<Database>;
+
 impl Deref for Database {
     type Target = Pool<Postgres>;
 

src/identity/mod.rs

@@ -0,0 +1 @@
+pub mod validator;

src/identity/validator.rs

@@ -0,0 +1,32 @@
+use ruint::uint;
+use semaphore::Field;
+
+use crate::identity_tree::Hash;
+
+// See <https://docs.rs/ark-bn254/latest/ark_bn254>
+pub const MODULUS: Field =
+    uint!(21888242871839275222246405745257275088548364400416034343698204186575808495617_U256);
+
+pub struct IdentityValidator {
+    snark_scalar_field: Hash,
+}
+
+// TODO Export the reduced-ness check that this is enabling from the
+//  `semaphore-rs` library when we bump the version.
+impl IdentityValidator {
+    pub fn new() -> Self {
+        Self {
+            snark_scalar_field: Hash::from(MODULUS),
+        }
+    }
+
+    pub fn identity_is_reduced(&self, commitment: Hash) -> bool {
+        commitment.lt(&self.snark_scalar_field)
+    }
+}
+
+impl Default for IdentityValidator {
+    fn default() -> Self {
+        Self::new()
+    }
+}