feat: basic db support

2026-07-21 03:56:23 +08:00 · 2022-08-09 18:58:18 +08:00
parent 73d7d4e1a8
commit 0083b7445a
9 changed files with 445 additions and 24 deletions
@@ -0,0 +1,185 @@
+import * as Y from 'yjs';
+import * as idb from 'lib0/indexeddb.js';
+import * as mutex from 'lib0/mutex.js';
+import { Observable } from 'lib0/observable.js';
+
+const customStoreName = 'custom';
+const updatesStoreName = 'updates';
+
+const PREFERRED_TRIM_SIZE = 500;
+
+const fetchUpdates = async (provider: IndexedDBProvider) => {
+    const [updatesStore] = idb.transact(provider.db as IDBDatabase, [
+        updatesStoreName,
+    ]); // , 'readonly')
+    const updates = await idb.getAll(
+        updatesStore,
+        idb.createIDBKeyRangeLowerBound(provider._dbref, false)
+    );
+    Y.transact(
+        provider.doc,
+        () => {
+            updates.forEach(val => Y.applyUpdate(provider.doc, val));
+        },
+        provider,
+        false
+    );
+    const lastKey = await idb.getLastKey(updatesStore);
+    provider._dbref = lastKey + 1;
+    const cnt = await idb.count(updatesStore);
+    provider._dbsize = cnt;
+    return updatesStore;
+};
+
+const storeState = (provider: IndexedDBProvider, forceStore = true) =>
+    fetchUpdates(provider).then(updatesStore => {
+        if (forceStore || provider._dbsize >= PREFERRED_TRIM_SIZE) {
+            idb.addAutoKey(updatesStore, Y.encodeStateAsUpdate(provider.doc))
+                .then(() =>
+                    idb.del(
+                        updatesStore,
+                        idb.createIDBKeyRangeUpperBound(provider._dbref, true)
+                    )
+                )
+                .then(() =>
+                    idb.count(updatesStore).then(cnt => {
+                        provider._dbsize = cnt;
+                    })
+                );
+        }
+    });
+
+export class IndexedDBProvider extends Observable<string> {
+    doc: Y.Doc;
+    name: string;
+    private _mux: mutex.mutex;
+    _dbref: number;
+    _dbsize: number;
+    private _destroyed: boolean;
+    whenSynced: Promise<IndexedDBProvider>;
+    db: IDBDatabase | null;
+    private _db: Promise<IDBDatabase>;
+    private synced: boolean;
+    private _storeTimeout: number;
+    private _storeTimeoutId: NodeJS.Timeout | null;
+    private _storeUpdate: (update: Uint8Array, origin: any) => void;
+
+    constructor(name: string, doc: Y.Doc) {
+        super();
+        this.doc = doc;
+        this.name = name;
+        this._mux = mutex.createMutex();
+        this._dbref = 0;
+        this._dbsize = 0;
+        this._destroyed = false;
+        this.db = null;
+        this.synced = false;
+        this._db = idb.openDB(name, db =>
+            idb.createStores(db, [
+                ['updates', { autoIncrement: true }],
+                ['custom'],
+            ])
+        );
+
+        this.whenSynced = this._db.then(async db => {
+            this.db = db;
+            const currState = Y.encodeStateAsUpdate(doc);
+            const updatesStore = await fetchUpdates(this);
+            await idb.addAutoKey(updatesStore, currState);
+            if (this._destroyed) return this;
+            this.emit('synced', [this]);
+            this.synced = true;
+            return this;
+        });
+
+        // Timeout in ms untill data is merged and persisted in idb.
+        this._storeTimeout = 1000;
+
+        this._storeTimeoutId = null;
+
+        this._storeUpdate = (update: Uint8Array, origin: any) => {
+            if (this.db && origin !== this) {
+                const [updatesStore] = idb.transact(
+                    /** @type {IDBDatabase} */ this.db,
+                    [updatesStoreName]
+                );
+                idb.addAutoKey(updatesStore, update);
+                if (++this._dbsize >= PREFERRED_TRIM_SIZE) {
+                    // debounce store call
+                    if (this._storeTimeoutId !== null) {
+                        clearTimeout(this._storeTimeoutId);
+                    }
+                    this._storeTimeoutId = setTimeout(() => {
+                        storeState(this, false);
+                        this._storeTimeoutId = null;
+                    }, this._storeTimeout);
+                }
+            }
+        };
+        doc.on('update', this._storeUpdate);
+        this.destroy = this.destroy.bind(this);
+        doc.on('destroy', this.destroy);
+    }
+
+    override destroy() {
+        if (this._storeTimeoutId) {
+            clearTimeout(this._storeTimeoutId);
+        }
+        this.doc.off('update', this._storeUpdate);
+        this.doc.off('destroy', this.destroy);
+        this._destroyed = true;
+        return this._db.then(db => {
+            db.close();
+        });
+    }
+
+    /**
+     * Destroys this instance and removes all data from SQLite.
+     *
+     * @return {Promise<void>}
+     */
+    async clearData(): Promise<void> {
+        return this.destroy().then(() => {
+            idb.deleteDB(this.name);
+        });
+    }
+
+    /**
+     * @param {String | number | ArrayBuffer | Date} key
+     * @return {Promise<String | number | ArrayBuffer | Date | any>}
+     */
+    async get(
+        key: string | number | ArrayBuffer | Date
+    ): Promise<string | number | ArrayBuffer | Date | any> {
+        return this._db.then(db => {
+            const [custom] = idb.transact(db, [customStoreName], 'readonly');
+            return idb.get(custom, key);
+        });
+    }
+
+    /**
+     * @param {String | number | ArrayBuffer | Date} key
+     * @param {String | number | ArrayBuffer | Date} value
+     * @return {Promise<String | number | ArrayBuffer | Date>}
+     */
+    async set(
+        key: string | number | ArrayBuffer | Date,
+        value: string | number | ArrayBuffer | Date
+    ): Promise<string | number | ArrayBuffer | Date> {
+        return this._db.then(db => {
+            const [custom] = idb.transact(db, [customStoreName]);
+            return idb.put(custom, value, key);
+        });
+    }
+
+    /**
+     * @param {String | number | ArrayBuffer | Date} key
+     * @return {Promise<undefined>}
+     */
+    async del(key: string | number | ArrayBuffer | Date): Promise<undefined> {
+        return this._db.then(db => {
+            const [custom] = idb.transact(db, [customStoreName]);
+            return idb.del(custom, key);
+        });
+    }
+}