feat: implement storage adapter

Author: openscript

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "typescript.tsdk": "node_modules/typescript/lib"
+}

src/index.ts

@@ -1,21 +1,83 @@
 import { Chunk, StorageAdapter, StorageKey } from '@automerge/automerge-repo';
 
 export class OPFSStorageAdapter extends StorageAdapter {
-  private baseDirectory: string
+  private baseDirectory: string;
+  private baseDirectoryHandle: FileSystemDirectoryHandle;
+  private root: FileSystemDirectoryHandle;
 
-  load(key: StorageKey): Promise<Uint8Array | undefined> {
-    throw new Error('Method not implemented.');
+  constructor(baseDirectory: string = "automerge-repo-data") {
+    super();
+    this.baseDirectory = baseDirectory;
+    this.initialize();
   }
-  save(key: StorageKey, data: Uint8Array): Promise<void> {
-    throw new Error('Method not implemented.');
+
+  async load(key: StorageKey): Promise<Uint8Array | undefined> {
+    const fileName = getKey(key);
+
+    try {
+      const fileHandle = await this.baseDirectoryHandle.getFileHandle(fileName);
+      const file = await fileHandle.getFile();
+      const arrayBuffer = await file.arrayBuffer();
+      return new Uint8Array(arrayBuffer);
+    } catch (error) {
+      // don't throw if file not found
+      if (error.code === "NotFoundError") return undefined
+      throw error;
+    }
+  }
+
+  async save(key: StorageKey, data: Uint8Array): Promise<void> {
+    const fileName = getKey(key);
+
+    const fileHandle = await this.baseDirectoryHandle.getFileHandle(fileName, { create: true });
+    const fileWritable = await fileHandle.createWritable();
+    await fileWritable.write(data);
+    return fileWritable.close();
+  }
+
+  async remove(key: StorageKey): Promise<void> {
+    const fileName = getKey(key);
+
+    try {
+      return this.baseDirectoryHandle.removeEntry(fileName);
+    } catch (error) {
+      // don't throw if file not found
+      if (error.code === "NotFoundError") return undefined
+      throw error;
+    }
   }
-  remove(key: StorageKey): Promise<void> {
-    throw new Error('Method not implemented.');
+
+  async loadRange(keyPrefix: StorageKey): Promise<Chunk[]> {
+    const chunks: Chunk[] = [];
+    const prefix = getKey(keyPrefix);
+
+    for await (const [name] of this.baseDirectoryHandle) {
+        if (name.startsWith(prefix)) {
+            const fileHandle = await this.baseDirectoryHandle.getFileHandle(name);
+            const file = await fileHandle.getFile();
+            const arrayBuffer = await file.arrayBuffer();
+            chunks.push({key: name.split("_"), data: new Uint8Array(arrayBuffer)});
+        }
+    }
+
+    return chunks;
   }
-  loadRange(keyPrefix: StorageKey): Promise<Chunk[]> {
-    throw new Error('Method not implemented.');
+
+  async removeRange(keyPrefix: StorageKey): Promise<void> {
+    const prefix = getKey(keyPrefix);
+
+    for await (const [name] of this.baseDirectoryHandle) {
+        if (name.startsWith(prefix)) {
+            await this.baseDirectoryHandle.removeEntry(name);
+        }
+    }
   }
-  removeRange(keyPrefix: StorageKey): Promise<void> {
-    throw new Error('Method not implemented.');
+
+  private async initialize() {
+    this.root = await navigator.storage.getDirectory();
+    this.baseDirectoryHandle = await this.root.getDirectoryHandle(this.baseDirectory, { create: true });
   }
+
 }
+
+const getKey = (key: StorageKey): string => key.join("_");

src/types.d.ts

@@ -0,0 +1,9 @@
+// dom.asynciterable haven't been released yet
+// see https://github.com/microsoft/TypeScript/pull/56723
+
+interface FileSystemDirectoryHandle {
+  [Symbol.asyncIterator](): AsyncIterableIterator<[string, FileSystemHandle]>;
+  entries(): AsyncIterableIterator<[string, FileSystemHandle]>;
+  keys(): AsyncIterableIterator<string>;
+  values(): AsyncIterableIterator<FileSystemHandle>;
+}

tsconfig.json

@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
     "target": "ESNext",
+    "lib": ["DOM"],
     "jsx": "react",
     "module": "NodeNext",
     "moduleResolution": "Node16",