lib: update js side of blob (#21)

Author: flakey5

lib/internal/blob.js

@@ -6,9 +6,7 @@ const {
   MathMin,
   ObjectDefineProperties,
   ObjectDefineProperty,
-  PromiseResolve,
   PromiseReject,
-  SafePromisePrototypeFinally,
   ReflectConstruct,
   RegExpPrototypeExec,
   RegExpPrototypeSymbolReplace,
@@ -22,7 +20,7 @@ const {
 
 const {
   createBlob: _createBlob,
-  FixedSizeBlobCopyJob,
+  concat,
   getDataObject,
 } = internalBinding('blob');
 
@@ -51,7 +49,6 @@ const {
 const { inspect } = require('internal/util/inspect');
 
 const {
-  AbortError,
   codes: {
     ERR_INVALID_ARG_TYPE,
     ERR_INVALID_ARG_VALUE,
@@ -66,13 +63,8 @@ const {
 } = require('internal/validators');
 
 const kHandle = Symbol('kHandle');
-const kState = Symbol('kState');
-const kIndex = Symbol('kIndex');
 const kType = Symbol('kType');
 const kLength = Symbol('kLength');
-const kArrayBufferPromise = Symbol('kArrayBufferPromise');
-
-const kMaxChunkSize = 65536;
 
 const disallowedTypeCharacters = /[^\u{0020}-\u{007E}]/u;
 
@@ -271,40 +263,23 @@ class Blob {
     if (!isBlob(this))
       return PromiseReject(new ERR_INVALID_THIS('Blob'));
 
-    // If there's already a promise in flight for the content,
-    // reuse it, but only while it's in flight. After the cached
-    // promise resolves it will be cleared, allowing it to be
-    // garbage collected as soon as possible.
-    if (this[kArrayBufferPromise])
-      return this[kArrayBufferPromise];
-
-    const job = new FixedSizeBlobCopyJob(this[kHandle]);
-
-    const ret = job.run();
-
-    // If the job returns a value immediately, the ArrayBuffer
-    // was generated synchronously and should just be returned
-    // directly.
-    if (ret !== undefined)
-      return PromiseResolve(ret);
-
-    const {
-      promise,
-      resolve,
-      reject,
-    } = createDeferredPromise();
-
-    job.ondone = (err, ab) => {
-      if (err !== undefined)
-        return reject(new AbortError(undefined, { cause: err }));
-      resolve(ab);
+    const { promise, resolve } = createDeferredPromise();
+    const reader = this[kHandle].getReader();
+    const buffers = [];
+    const readNext = () => {
+      const result = reader.pull((status, buffer) => {
+        if (status === -1) {
+          // EOS, concat & resolve
+          // buffer should be undefined here
+          resolve(concat(buffers));
+          return;
+        }
+        buffers.push(buffer);
+        readNext();
+      });
     };
-    this[kArrayBufferPromise] =
-    SafePromisePrototypeFinally(
-      promise,
-      () => this[kArrayBufferPromise] = undefined);
-
-    return this[kArrayBufferPromise];
+    readNext();
+    return promise;
   }
 
   /**
@@ -326,22 +301,22 @@ class Blob {
     if (!isBlob(this))
       throw new ERR_INVALID_THIS('Blob');
 
-    const self = this;
+    const reader = this[kHandle].getReader();
     return new lazyReadableStream({
-      async start() {
-        this[kState] = await self.arrayBuffer();
-        this[kIndex] = 0;
-      },
-
-      pull(controller) {
-        if (this[kState].byteLength - this[kIndex] <= kMaxChunkSize) {
-          controller.enqueue(new Uint8Array(this[kState], this[kIndex]));
-          controller.close();
-          this[kState] = undefined;
-        } else {
-          controller.enqueue(new Uint8Array(this[kState], this[kIndex], kMaxChunkSize));
-          this[kIndex] += kMaxChunkSize;
-        }
+      #reader: reader,
+      pull(c) {
+        const { promise, resolve } = createDeferredPromise();
+        reader.pull((status, buffer) => {
+          if (status === 1) {
+            // EOS
+            c.close();
+            resolve();
+            return;
+          }
+          c.enqueue(new Uint8Array(buffer));
+          resolve();
+        });
+        return promise;
       }
     });
   }

lib/internal/fs/promises.js

@@ -25,6 +25,8 @@ const {
   S_IFREG
 } = constants;
 
+const { createBlobFromFileHandle } = internalBinding('blob');
+
 const binding = internalBinding('fs');
 const { Buffer } = require('buffer');
 
@@ -310,6 +312,14 @@ class FileHandle extends EventEmitterMixin(JSTransferable) {
     return new WriteStream(undefined, { ...options, fd: this });
   }
 
+  /**
+   * @typedef {import('../blob').Blob} Blob
+   * @returns {Blob}
+   */
+  blob() {
+    return createBlobFromFileHandle(this);
+  }
+
   [kTransfer]() {
     if (this[kClosePromise] || this[kRefs] > 1) {
       throw lazyDOMException('Cannot transfer FileHandle while in use',

src/node_blob.cc

@@ -37,56 +37,6 @@ using v8::Value;
 
 namespace {
 
-// TODO(@flakey5, @jasnell): Update the JavaScript side of blob...
-//
-// Within the JavaScript Blob object, the arrayBuffer() method will change significantly.
-// the pattern will be something like:
-//
-// const { createDeferredPromise } = require('internal/util');
-// const { concat, ...} = internalBinding('blob');
-//
-// function arrayBuffer() {
-//   const { promise, resolve } = createDeferredPromise();
-//   const reader = this.#buffer.getReader();
-//   const buffers = [];
-//   const readNext = () => {
-//     const result = reader.pull((status, buffer) => {
-//       if (status == -1) {
-//         // EOS, concat and resolve.
-//         // buffer should be undefined here.
-//         resolve(concat(buffers));
-//         return;
-//       }
-//       buffers.push(buffer);
-//       readNext();
-//     });
-//   };
-//   readNext();  // Starts the read loop
-//   return promise;
-// }
-//
-// For the stream() method, the pattern will be something like:
-//
-// function stream() {
-//   const reader = this.#buffer.getReader();
-//   return new ReadableStream({
-//     #reader = reader;
-//     pull(c) {
-//       const { promise, resolve } = createDeferredPromise();
-//       reader.pull((status, buffer) => {
-//         if (status === -1) {  // EOS
-//           c.close();
-//           resolve();
-//           return;
-//         }
-//         c.enqueue(new Uint8Array(buffer));
-//         resolve();
-//       });
-//       return promise;
-//     }
-//   });
-// }
-
 // Concatenate multiple ArrayBufferView/ArrayBuffers into a single ArrayBuffer.
 // This method treats all ArrayBufferView types the same.
 void Concat(const FunctionCallbackInfo<Value>& args) {