From 781ca741ddc6865fae7d1147062ca8e98c86fa51 Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Sun, 6 Aug 2023 22:21:46 -0500
Subject: [PATCH] Implement the DenoSqliteDriver correctly

---
 lib/kysely-deno-sqlite/deps.ts                |   6 +-
 .../src/deno-sqlite-driver.ts                 | 123 +++++++++++++-----
 2 files changed, 93 insertions(+), 36 deletions(-)

diff --git a/lib/kysely-deno-sqlite/deps.ts b/lib/kysely-deno-sqlite/deps.ts
index ff95c11..71a9fa8 100644
--- a/lib/kysely-deno-sqlite/deps.ts
+++ b/lib/kysely-deno-sqlite/deps.ts
@@ -1,17 +1,17 @@
 export {
+  CompiledQuery,
+  type DatabaseConnection,
   type DatabaseIntrospector,
   type Dialect,
   type DialectAdapter,
   type Driver,
   Kysely,
   type QueryCompiler,
+  type QueryResult,
   SqliteAdapter,
-  type SqliteDatabase,
   type SqliteDialectConfig,
-  SqliteDriver,
   SqliteIntrospector,
   SqliteQueryCompiler,
-  type SqliteStatement,
 } from 'npm:kysely@^0.25.0';
 
 export type { DB as DenoSqlite } from 'https://deno.land/x/sqlite@v3.7.3/mod.ts';
diff --git a/lib/kysely-deno-sqlite/src/deno-sqlite-driver.ts b/lib/kysely-deno-sqlite/src/deno-sqlite-driver.ts
index c68809e..b0d4655 100644
--- a/lib/kysely-deno-sqlite/src/deno-sqlite-driver.ts
+++ b/lib/kysely-deno-sqlite/src/deno-sqlite-driver.ts
@@ -1,50 +1,107 @@
-import { type DenoSqlite, type SqliteDatabase, SqliteDriver, type SqliteStatement } from '../deps.ts';
+import { CompiledQuery, type DatabaseConnection, type DenoSqlite, type Driver, type QueryResult } from '../deps.ts';
 
 import type { DenoSqliteDialectConfig } from './deno-sqlite-dialect-config.ts';
 
-class DenoSqliteDriver extends SqliteDriver {
+class DenoSqliteDriver implements Driver {
+  readonly #config: DenoSqliteDialectConfig;
+  readonly #connectionMutex = new ConnectionMutex();
+
+  #db?: DenoSqlite;
+  #connection?: DatabaseConnection;
+
   constructor(config: DenoSqliteDialectConfig) {
-    super({
-      ...config,
-      database: async () =>
-        new DenoSqliteDatabase(
-          typeof config.database === 'function' ? await config.database() : config.database,
-        ),
-    });
+    this.#config = Object.freeze({ ...config });
+  }
+
+  async init(): Promise<void> {
+    this.#db = typeof this.#config.database === 'function' ? await this.#config.database() : this.#config.database;
+
+    this.#connection = new DenoSqliteConnection(this.#db);
+
+    if (this.#config.onCreateConnection) {
+      await this.#config.onCreateConnection(this.#connection);
+    }
+  }
+
+  async acquireConnection(): Promise<DatabaseConnection> {
+    // SQLite only has one single connection. We use a mutex here to wait
+    // until the single connection has been released.
+    await this.#connectionMutex.lock();
+    return this.#connection!;
+  }
+
+  async beginTransaction(connection: DatabaseConnection): Promise<void> {
+    await connection.executeQuery(CompiledQuery.raw('begin'));
+  }
+
+  async commitTransaction(connection: DatabaseConnection): Promise<void> {
+    await connection.executeQuery(CompiledQuery.raw('commit'));
+  }
+
+  async rollbackTransaction(connection: DatabaseConnection): Promise<void> {
+    await connection.executeQuery(CompiledQuery.raw('rollback'));
+  }
+
+  // deno-lint-ignore require-await
+  async releaseConnection(): Promise<void> {
+    this.#connectionMutex.unlock();
+  }
+
+  // deno-lint-ignore require-await
+  async destroy(): Promise<void> {
+    this.#db?.close();
   }
 }
 
-/** HACK: This is an adapter class. */
-class DenoSqliteDatabase implements SqliteDatabase {
-  #db: DenoSqlite;
+class DenoSqliteConnection implements DatabaseConnection {
+  readonly #db: DenoSqlite;
 
   constructor(db: DenoSqlite) {
     this.#db = db;
   }
 
-  close(): void {
-    this.#db.close();
+  executeQuery<O>({ sql, parameters }: CompiledQuery): Promise<QueryResult<O>> {
+    const query = this.#db.prepareQuery(sql);
+
+    const rows = query.allEntries(parameters as any);
+    const { changes, lastInsertRowId } = this.#db;
+
+    query.finalize();
+
+    return Promise.resolve({
+      rows: rows as O[],
+      numAffectedRows: BigInt(changes),
+      insertId: BigInt(lastInsertRowId),
+    });
   }
 
-  prepare(sql: string): SqliteStatement {
-    const query = this.#db.prepareQuery(sql);
-    return {
-      // HACK: implement an actual driver to fix this.
-      reader: true,
-      all: (parameters: ReadonlyArray<unknown>) => {
-        const result = query.allEntries(parameters as any);
-        query.finalize();
-        return result;
-      },
-      run: (parameters: ReadonlyArray<unknown>) => {
-        query.execute(parameters as any);
-        query.finalize();
-        return {
-          changes: this.#db.changes,
-          lastInsertRowid: this.#db.lastInsertRowId,
-        };
-      },
-    };
+  // deno-lint-ignore require-yield
+  async *streamQuery<R>(): AsyncIterableIterator<QueryResult<R>> {
+    throw new Error('Sqlite driver doesn\'t support streaming');
+  }
+}
+
+class ConnectionMutex {
+  #promise?: Promise<void>;
+  #resolve?: () => void;
+
+  async lock(): Promise<void> {
+    while (this.#promise) {
+      await this.#promise;
+    }
+
+    this.#promise = new Promise((resolve) => {
+      this.#resolve = resolve;
+    });
+  }
+
+  unlock(): void {
+    const resolve = this.#resolve;
+
+    this.#promise = undefined;
+    this.#resolve = undefined;
+
+    resolve?.();
   }
 }