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// deno-lint-ignore-file require-awaitimport { DB } from "https://deno.land/x/sqlite@v2.5.0/mod.ts";
import { Adapter, AdapterParams, adapters } from './mod.ts';
const CREATE = 'CREATE TABLE IF NOT EXISTS [kv-storage] (area TEXT, key TEXT, value TEXT, PRIMARY KEY (area, key))';const GET = 'SELECT value FROM [kv-storage] WHERE key=:key AND area=:area';const UPSERT = 'INSERT INTO [kv-storage] (area, key, value) VALUES (:area, :key, :value) ON CONFLICT(area, key) DO UPDATE SET value=:value';const DELETE = 'DELETE FROM [kv-storage] WHERE key=:key AND area=:area';const CLEAR = 'DELETE FROM [kv-storage] WHERE area=:area';const KEYS = 'SELECT key FROM [kv-storage] WHERE area=:area';const VALUES = 'SELECT value FROM [kv-storage] WHERE area=:area';const ENTRIES = 'SELECT key, value FROM [kv-storage] WHERE area=:area';
export class SQLiteAdapter implements Adapter {  private filename: string;  private area: string;  private db?: DB;  private memory: boolean;  private refs = 0
  constructor({ area, url }: AdapterParams) {    this.area = area;
    const filename = url.substring('sqlite://'.length);    const memory = this.memory = ['', 'memory'].includes(filename ?? '');    const db = this.db = new DB(this.filename = memory ? ':memory:' : filename);    [...db.query(CREATE)];    this.keepOpen();  }
  private keepOpen() {    if (!this.memory) queueMicrotask(() => {      if (this.refs === 0) {        this.db?.close()        delete this.db;      }    })  }
  private query(query: string, params?: { key?: string, value?: string }) {    const db = this.db ||= new DB(this.filename);    const rows = db.query(query, { ...params, area: this.area });    return rows;  }
  async get(key: string): Promise<string | undefined> {    const res = this.query(GET, { key }).next().value?.[0];    this.keepOpen()    return res;  }
  async set(key: string, value: string) {    [...this.query(UPSERT, { key, value })];    this.keepOpen()  }
  async delete(key: string) {    [...this.query(DELETE, { key })];    this.keepOpen()  }
  async clear() {    [...this.query(CLEAR)];    this.keepOpen()  }
  async *keys() {    try {      this.refs++      for (const [key] of this.query(KEYS)) {        yield key;      }    } finally {      this.refs--;      this.keepOpen()    }  }
  async *values() {    try {      this.refs++      for (const [value] of this.query(VALUES)) {        yield value;      }    } finally {      this.refs--      this.keepOpen()    }  }
  async *entries() {    try {      this.refs++      for (const [key, value] of this.query(ENTRIES)) {        yield [key, value] as const;      }    } finally {      this.refs--;      this.keepOpen()    }  }
  backingStore() {    return this.db ?? new DB(this.filename);  }}
adapters.set('sqlite:', SQLiteAdapter);