change to BackendManager

Author: connortsui20

optd-persistent/src/lib.rs

@@ -1,3 +1,5 @@
+use std::sync::atomic::AtomicUsize;
+
 use sea_orm::*;
 use sea_orm_migration::prelude::*;
 
@@ -10,11 +12,43 @@ mod expression;
 
 mod memo;
 pub use memo::interface::Memo;
-pub use memo::orm::MemoTable;
 
 pub const DATABASE_URL: &str = "sqlite:./sqlite.db?mode=rwc";
 pub const DATABASE_FILE: &str = "./sqlite.db";
 
+/// The different kinds of errors that might occur while running operations on a memo table.
+pub enum MemoError {
+    UnknownGroup,
+    UnknownLogicalExpression,
+    UnknownPhysicalExpression,
+    InvalidExpression,
+    Database(DbErr),
+}
+
+impl From<DbErr> for MemoError {
+    fn from(value: DbErr) -> Self {
+        MemoError::Database(value)
+    }
+}
+
+/// A type alias for a result with [`MemoError`] as the error type.
+pub type Result<T> = std::result::Result<T, MemoError>;
+
+pub struct BackendManager {
+    db: DatabaseConnection,
+    latest_epoch_id: AtomicUsize,
+}
+
+impl BackendManager {
+    /// Creates a new `BackendManager`.
+    pub async fn new() -> Result<Self> {
+        Ok(Self {
+            db: Database::connect(DATABASE_URL).await?,
+            latest_epoch_id: AtomicUsize::new(0),
+        })
+    }
+}
+
 pub async fn migrate(db: &DatabaseConnection) -> std::result::Result<(), DbErr> {
     Migrator::refresh(db).await
 }

optd-persistent/src/memo/interface.rs

@@ -1,22 +1,4 @@
-use sea_orm::*;
-
-/// The different kinds of errors that might occur while running operations on a memo table.
-pub enum MemoError {
-    UnknownGroup,
-    UnknownLogicalExpression,
-    UnknownPhysicalExpression,
-    InvalidExpression,
-    Database(DbErr),
-}
-
-impl From<DbErr> for MemoError {
-    fn from(value: DbErr) -> Self {
-        MemoError::Database(value)
-    }
-}
-
-/// A type alias for a result with [`MemoError`] as the error type.
-pub type Result<T> = std::result::Result<T, MemoError>;
+use crate::Result;
 
 /// A trait representing an implementation of a memoization table.
 ///
@@ -114,7 +96,7 @@ pub trait Memo {
     ///
     /// If the group does not exist, returns a [`MemoError::UnknownGroup`] error.
     async fn update_group_winner(
-        &mut self,
+        &self,
         group_id: Self::GroupId,
         physical_expression_id: Self::PhysicalExpressionId,
     ) -> Result<Option<Self::PhysicalExpressionId>>;
@@ -123,7 +105,7 @@ pub trait Memo {
     ///
     /// If the group does not exist, returns a [`MemoError::UnknownGroup`] error.
     async fn add_logical_expression_to_group(
-        &mut self,
+        &self,
         group_id: Self::GroupId,
         logical_expression: Self::LogicalExpression,
     ) -> Result<()>;
@@ -132,7 +114,7 @@ pub trait Memo {
     ///
     /// If the group does not exist, returns a [`MemoError::UnknownGroup`] error.
     async fn add_physical_expression_to_group(
-        &mut self,
+        &self,
         group_id: Self::GroupId,
         physical_expression: Self::PhysicalExpression,
     ) -> Result<()>;
@@ -150,7 +132,7 @@ pub trait Memo {
     /// If the expression does not exist, this function will create a new group and a new
     /// expression, returning brand new IDs for both.
     async fn add_logical_expression(
-        &mut self,
+        &self,
         expression: Self::LogicalExpression,
     ) -> Result<(Self::GroupId, Self::LogicalExpressionId)>;
 }

optd-persistent/src/memo/orm.rs

@@ -1,25 +1,10 @@
 use crate::{
     entities::{prelude::*, *},
-    DATABASE_URL,
+    BackendManager, {Memo, MemoError, Result},
 };
 use sea_orm::*;
 
-use super::interface::{Memo, MemoError, Result};
-
-pub struct MemoTable {
-    db: DatabaseConnection,
-}
-
-impl MemoTable {
-    /// Creates a new `MemoTable`.
-    pub async fn new() -> Result<Self> {
-        Ok(Self {
-            db: Database::connect(DATABASE_URL).await?,
-        })
-    }
-}
-
-impl Memo for MemoTable {
+impl Memo for BackendManager {
     type Group = cascades_group::Model;
     type GroupId = i32;
     type LogicalExpression = logical_expression::Model;
@@ -113,7 +98,7 @@ impl Memo for MemoTable {
     }
 
     async fn update_group_winner(
-        &mut self,
+        &self,
         group_id: Self::GroupId,
         physical_expression_id: Self::PhysicalExpressionId,
     ) -> Result<Option<Self::PhysicalExpressionId>> {
@@ -130,7 +115,7 @@ impl Memo for MemoTable {
     }
 
     async fn add_logical_expression_to_group(
-        &mut self,
+        &self,
         group_id: Self::GroupId,
         logical_expression: Self::LogicalExpression,
     ) -> Result<()> {
@@ -151,7 +136,7 @@ impl Memo for MemoTable {
     }
 
     async fn add_physical_expression_to_group(
-        &mut self,
+        &self,
         group_id: Self::GroupId,
         physical_expression: Self::PhysicalExpression,
     ) -> Result<()> {
@@ -173,7 +158,7 @@ impl Memo for MemoTable {
 
     /// Note that in this function, we ignore the group ID that the logical expression contains.
     async fn add_logical_expression(
-        &mut self,
+        &self,
         expression: Self::LogicalExpression,
     ) -> Result<(Self::GroupId, Self::LogicalExpressionId)> {
         // Lookup all expressions that have the same fingerprint. There may be false positives, but