feat: extract common and simplify export opfs

Author: subframe7536

playground/src/index.ts

@@ -59,6 +59,15 @@ document.querySelector('.download')?.addEventListener('click', async () => {
   }
 })
 
+document.querySelector('.downloadW')?.addEventListener('click', async () => {
+  const worker = new OpfsWorker()
+  worker.postMessage('dl')
+  worker.onmessage = (buf: any) => {
+    download(buf)
+    worker.terminate()
+  }
+})
+
 const ee = mitt<{
   data: [any]
   done: []

playground/src/worker.ts

@@ -10,9 +10,13 @@ onmessage = async ({ data }) => {
   }
   const db = await initSQLite(useOpfsStorage(
     'test.db',
-    data ? withExistDB(data, { url }) : { url },
+    (data && data !== 'dl') ? withExistDB(data, { url }) : { url },
     // { url },
   ))
+  if (data === 'dl') {
+    postMessage(await db.dump())
+    return
+  }
   // if (data) {
   //   await db.sync(data)
   // }

src/io/common.ts

@@ -1,4 +1,4 @@
-import type { Promisable } from '../types'
+import type { FacadeVFS, Promisable } from '../types'
 import { SQLITE_OK } from '../constant'
 
 export async function check(code: Promisable<number>): Promise<void> {
@@ -10,3 +10,12 @@ export async function check(code: Promisable<number>): Promise<void> {
 export function ignoredDataView(): DataView {
   return new DataView(new ArrayBuffer(4))
 }
+export async function getHandleFromPath(path: string): Promise<FileSystemFileHandle> {
+  const root = await navigator.storage.getDirectory()
+  const handle = await root.getFileHandle(path, { create: true })
+  return handle
+}
+
+export function isOpfsVFS(vfs: FacadeVFS): boolean {
+  return 'releaser' in vfs
+}

src/io/export.ts

@@ -6,7 +6,7 @@ import {
   SQLITE_OPEN_MAIN_DB,
   SQLITE_OPEN_READONLY,
 } from '../constant'
-import { check, ignoredDataView } from './common'
+import { check, getHandleFromPath, ignoredDataView, isOpfsVFS } from './common'
 
 export function dumpReadableStream(vfs: FacadeVFS, path: string): ReadableStream {
   const source = getExistDataSource(vfs, path)
@@ -111,5 +111,10 @@ export async function streamToUint8Array(stream: ReadableStream): Promise<Uint8A
  * @param path database path
  */
 export async function exportDatabase(vfs: FacadeVFS, path: string): Promise<Uint8Array> {
-  return await streamToUint8Array(dumpReadableStream(vfs, path))
+  return isOpfsVFS(vfs)
+    ? await getHandleFromPath(path)
+      .then(handle => handle.getFile())
+      .then(file => file.arrayBuffer())
+      .then(buf => new Uint8Array(buf))
+    : await streamToUint8Array(dumpReadableStream(vfs, path))
 }

src/io/import.ts

@@ -14,7 +14,7 @@ import {
   SQLITE_OPEN_READWRITE,
   SQLITE_SYNC_NORMAL,
 } from '../constant'
-import { check, ignoredDataView } from './common'
+import { check, getHandleFromPath, ignoredDataView, isOpfsVFS } from './common'
 
 const SQLITE_BINARY_HEADER = new Uint8Array([
   0x53, 0x51, 0x4C, 0x69, 0x74, 0x65, 0x20, 0x66, // SQLite f
@@ -124,8 +124,7 @@ async function importDatabaseToOpfs(
   path: string,
   source: ReadableStream<Uint8Array>,
 ): Promise<void> {
-  const root = await navigator.storage.getDirectory()
-  const handle = await root.getFileHandle(path, { create: true })
+  const handle = await getHandleFromPath(path)
   const [streamForVerify, streamData] = source.tee()
 
   await parseHeaderAndVerify(streamForVerify.getReader())
@@ -148,7 +147,7 @@ export async function importDatabase(
 ): Promise<void> {
   const stream = data instanceof globalThis.File ? data.stream() : data
   // is `OPFSCoopSyncVFS`
-  if ('releaser' in vfs) {
+  if (isOpfsVFS(vfs)) {
     await importDatabaseToOpfs(path, stream)
   } else {
     await importDatabaseToIdb(vfs, path, stream)