feat: fix missing createWritable in safari (#62)

* feat: fix missing createWritable in safari

* make it easier for bundlers

* fix check

example/test.html

@@ -56,7 +56,7 @@
       <caption>Browser storage</caption>
       <thead><tr>
         <td>Test</td>
-        <td>Native</td>
+        <td>Native (Somewhat patched to fix buggy safari impl)</td>
         <td>Sandbox</td>
         <td>Memory</td>
         <td>IndexedDB</td>

src/FileSystemDirectoryHandle.js

@@ -1,4 +1,7 @@
 import FileSystemHandle from './FileSystemHandle.js'
+import { errors } from './util.js'
+
+const { GONE, MOD_ERR } = errors
 
 const kAdapter = Symbol('adapter')
 
@@ -90,6 +93,7 @@ class FileSystemDirectoryHandle extends FileSystemHandle {
 
     while (openSet.length) {
       let { handle: current, path } = openSet.pop()
+
       for await (const entry of current.values()) {
         if (await entry.isSameEntry(possibleDescendant)) {
           return [...path, entry.name]
@@ -132,5 +136,62 @@ Object.defineProperties(FileSystemDirectoryHandle.prototype, {
 	removeEntry: { enumerable: true }
 })
 
+if (globalThis.FileSystemDirectoryHandle) {
+  const proto = globalThis.FileSystemDirectoryHandle.prototype
+
+  proto.resolve = async function resolve (possibleDescendant) {
+    if (await possibleDescendant.isSameEntry(this)) {
+      return []
+    }
+
+    const openSet = [{ handle: this, path: [] }]
+
+    while (openSet.length) {
+      let { handle: current, path } = openSet.pop()
+
+      for await (const entry of current.values()) {
+        if (await entry.isSameEntry(possibleDescendant)) {
+          return [...path, entry.name]
+        }
+        if (entry.kind === 'directory') {
+          openSet.push({ handle: entry, path: [...path, entry.name] })
+        }
+      }
+    }
+
+    return null
+  }
+
+  // Safari allows us operate on deleted files,
+  // so we need to check if they still exist.
+  // Hope to remove this one day.
+  async function ensureDoActuallyStillExist (handle) {
+    const root = await navigator.storage.getDirectory()
+    const path = await root.resolve(handle)
+    if (path === null) { throw new DOMException(...GONE) }
+  }
+
+  const entries = proto.entries
+  proto.entries = async function * () {
+    await ensureDoActuallyStillExist(this)
+    yield * entries.call(this)
+  }
+  proto[Symbol.asyncIterator] = async function * () {
+    yield * this.entries()
+  }
+
+  const removeEntry = proto.removeEntry
+  proto.removeEntry = async function (name, options = {}) {
+    return removeEntry.call(this, name, options).catch(async err => {
+      const unknown = err instanceof DOMException && err.name === 'UnknownError'
+      if (unknown && !options.recursive) {
+        const empty = (await entries.call(this).next()).done
+        if (!empty) { throw new DOMException(...MOD_ERR) }
+      }
+      throw err
+    })
+  }
+}
+
 export default FileSystemDirectoryHandle
 export { FileSystemDirectoryHandle }

src/FileSystemFileHandle.js

@@ -1,5 +1,8 @@
 import FileSystemHandle from './FileSystemHandle.js'
 import FileSystemWritableFileStream from './FileSystemWritableFileStream.js'
+import { errors } from './util.js'
+
+const { INVALID, SYNTAX, GONE } = errors
 
 const kAdapter = Symbol('adapter')
 
@@ -43,5 +46,183 @@ Object.defineProperties(FileSystemFileHandle.prototype, {
   getFile: { enumerable: true }
 })
 
+// Safari doesn't support async createWritable streams yet.
+if (
+  globalThis.FileSystemFileHandle &&
+  !globalThis.FileSystemFileHandle.prototype.createWritable
+) {
+  const wm = new WeakMap()
+
+  let workerUrl
+
+  // Worker code that should be inlined (can't use any external functions)
+  function code () {
+    let fileHandle, handle
+
+    onmessage = async evt => {
+      const port = evt.ports[0]
+      const cmd = evt.data
+      switch (cmd.type) {
+        case 'open':
+          const file = cmd.name
+
+          let dir = await navigator.storage.getDirectory()
+
+          for (const folder of cmd.path) {
+            dir = await dir.getDirectoryHandle(folder)
+          }
+
+          fileHandle = await dir.getFileHandle(file)
+          handle = await fileHandle.createSyncAccessHandle()
+          break
+        case 'write':
+          handle.write(cmd.data, { at: cmd.position })
+          handle.flush()
+          break
+        case 'truncate':
+          handle.truncate(cmd.size)
+          break
+        case 'abort':
+        case 'close':
+          handle.close()
+          break
+      }
+
+      port.postMessage(0)
+    }
+  }
+
+
+  globalThis.FileSystemFileHandle.prototype.createWritable = async function (options) {
+    // Safari only support writing data in a worker with sync access handle.
+    if (!workerUrl) {
+      const blob = new Blob([code.toString() + `;${code.name}();`], {
+        type: 'text/javascript'
+      })
+      workerUrl = URL.createObjectURL(blob)
+    }
+    const worker = new Worker(workerUrl, { type: 'module' })
+
+    let position = 0
+    const textEncoder = new TextEncoder()
+    let size = await this.getFile().then(file => file.size)
+
+    const send = message => new Promise((resolve, reject) => {
+      const mc = new MessageChannel()
+      mc.port1.onmessage = evt => {
+        if (evt.data instanceof Error) reject(evt.data)
+        else resolve(evt.data)
+        mc.port1.close()
+        mc.port2.close()
+        mc.port1.onmessage = null
+      }
+      worker.postMessage(message, [mc.port2])
+    })
+
+    // Safari also don't support transferable file system handles.
+    // So we need to pass the path to the worker. This is a bit hacky and ugly.
+    const root = await navigator.storage.getDirectory()
+    const parent = await wm.get(this)
+    const path = await parent.resolve(root)
+
+    // Should likely never happen, but just in case...
+    if (path === null) throw new DOMException(...GONE)
+
+    let controller
+    await send({ type: 'open', path, name: this.name })
+
+    if (options?.keepExistingData === false) {
+      await send({ type: 'truncate', size: 0 })
+      size = 0
+    }
+
+    const ws = new FileSystemWritableFileStream({
+      start: ctrl => {
+        controller = ctrl
+      },
+      async write(chunk) {
+        const isPlainObject = chunk?.constructor === Object
+
+        if (isPlainObject) {
+          chunk = { ...chunk }
+        } else {
+          chunk = { type: 'write', data: chunk, position }
+        }
+
+        if (chunk.type === 'write') {
+          if (!('data' in chunk)) {
+            await send({ type: 'close' })
+            throw new DOMException(...SYNTAX('write requires a data argument'))
+          }
+
+          chunk.position ??= position
+
+          if (typeof chunk.data === 'string') {
+            chunk.data = textEncoder.encode(chunk.data)
+          }
+
+          else if (chunk.data instanceof ArrayBuffer) {
+            chunk.data = new Uint8Array(chunk.data)
+          }
+
+          else if (!(chunk.data instanceof Uint8Array) && ArrayBuffer.isView(chunk.data)) {
+            chunk.data = new Uint8Array(chunk.data.buffer, chunk.data.byteOffset, chunk.data.byteLength)
+          }
+
+          else if (!(chunk.data instanceof Uint8Array)) {
+            const ab = await new Response(chunk.data).arrayBuffer()
+            chunk.data = new Uint8Array(ab)
+          }
+
+          if (Number.isInteger(chunk.position) && chunk.position >= 0) {
+            position = chunk.position
+          }
+          position += chunk.data.byteLength
+          size += chunk.data.byteLength
+        } else if (chunk.type === 'seek') {
+          if (Number.isInteger(chunk.position) && chunk.position >= 0) {
+            if (size < chunk.position) {
+              throw new DOMException(...INVALID)
+            }
+            console.log('seeking', chunk)
+            position = chunk.position
+            return // Don't need to enqueue seek...
+          } else {
+            await send({ type: 'close' })
+            throw new DOMException(...SYNTAX('seek requires a position argument'))
+          }
+        } else if (chunk.type === 'truncate') {
+          if (Number.isInteger(chunk.size) && chunk.size >= 0) {
+            size = chunk.size
+            if (position > size) { position = size }
+          } else {
+            await send({ type: 'close' })
+            throw new DOMException(...SYNTAX('truncate requires a size argument'))
+          }
+        }
+
+        await send(chunk)
+      },
+      async close () {
+        await send({ type: 'close' })
+        worker.terminate()
+      },
+      async abort (reason) {
+        await send({ type: 'abort', reason })
+        worker.terminate()
+      },
+    })
+
+    return ws
+  }
+
+  const orig = FileSystemDirectoryHandle.prototype.getFileHandle
+  FileSystemDirectoryHandle.prototype.getFileHandle = async function (...args) {
+    const handle = await orig.call(this, ...args)
+    wm.set(handle, this)
+    return handle
+  }
+}
+
 export default FileSystemFileHandle
 export { FileSystemFileHandle }

src/FileSystemHandle.js

@@ -1,5 +1,9 @@
 const kAdapter = Symbol('adapter')
 
+/**
+ * @typedef {Object} FileSystemHandlePermissionDescriptor
+ * @property {('read'|'readwrite')} [mode='read']
+ */
 class FileSystemHandle {
   /** @type {FileSystemHandle} */
   [kAdapter]
@@ -16,7 +20,9 @@ class FileSystemHandle {
     this[kAdapter] = adapter
   }
 
-  async queryPermission ({mode = 'read'} = {}) {
+  /** @param {FileSystemHandlePermissionDescriptor} descriptor */
+  async queryPermission (descriptor = {}) {
+    const { mode = 'read' } = descriptor
     const handle = this[kAdapter]
 
     if (handle.queryPermission) {
@@ -79,5 +85,12 @@ Object.defineProperty(FileSystemHandle.prototype, Symbol.toStringTag, {
   configurable: true
 })
 
+// Safari safari doesn't support writable streams yet.
+if (globalThis.FileSystemHandle) {
+  globalThis.FileSystemHandle.prototype.queryPermission ??= function (descriptor) {
+    return 'granted'
+  }
+}
+
 export default FileSystemHandle
 export { FileSystemHandle }

src/FileSystemWritableFileStream.js

@@ -3,9 +3,10 @@ import config from './config.js'
 const { WritableStream } = config
 
 class FileSystemWritableFileStream extends WritableStream {
-  constructor (...args) {
-    super(...args)
-
+  #writer
+  constructor (writer) {
+    super(writer)
+    this.#writer = writer
     // Stupid Safari hack to extend native classes
     // https://bugs.webkit.org/show_bug.cgi?id=226201
     Object.setPrototypeOf(this, FileSystemWritableFileStream.prototype)
@@ -14,7 +15,7 @@ class FileSystemWritableFileStream extends WritableStream {
     this._closed = false
   }
 
-  close () {
+  async close () {
     this._closed = true
     const w = this.getWriter()
     const p = w.close()
@@ -33,15 +34,23 @@ class FileSystemWritableFileStream extends WritableStream {
     return this.write({ type: 'truncate', size })
   }
 
+  // The write(data) method steps are:
   write (data) {
     if (this._closed) {
       return Promise.reject(new TypeError('Cannot write to a CLOSED writable stream'))
     }
 
+    // 1. Let writer be the result of getting a writer for this.
     const writer = this.getWriter()
-    const p = writer.write(data)
+
+    // 2. Let result be the result of writing a chunk to writer given data.
+    const result = writer.write(data)
+
+    // 3. Release writer.
     writer.releaseLock()
-    return p
+
+    // 4. Return result.
+    return result
   }
 }
 
@@ -59,5 +68,14 @@ Object.defineProperties(FileSystemWritableFileStream.prototype, {
   write: { enumerable: true }
 })
 
+// Safari safari doesn't support writable streams yet.
+if (
+  globalThis.FileSystemFileHandle &&
+  !globalThis.FileSystemFileHandle.prototype.createWritable &&
+  !globalThis.FileSystemWritableFileStream
+) {
+  globalThis.FileSystemWritableFileStream = FileSystemWritableFileStream
+}
+
 export default FileSystemWritableFileStream
 export { FileSystemWritableFileStream }

src/adapters/indexeddb.js

@@ -2,7 +2,16 @@
 
 import { errors } from '../util.js'
 
-const { INVALID, GONE, MISMATCH, MOD_ERR, SYNTAX } = errors
+const { INVALID, GONE, MISMATCH, MOD_ERR, SYNTAX, ABORT } = errors
+
+/**
+ * @param {IDBTransaction} tx
+ * @param {(e) => {}} onerror
+ */
+function setupTxErrorHandler (tx, onerror) {
+  tx.onerror = () => onerror(tx.error)
+  tx.onabort = () => onerror(tx.error || new DOMException(...ABORT))
+}
 
 class Sink {
   /**