add proper support for typed arrays in remote (#13055)

lib/common/buffer-utils.js

@@ -0,0 +1,58 @@
+// Note: Don't use destructuring assignment for `Buffer`, or we'll hit a
+// browserify bug that makes the statement invalid, throwing an error in
+// sandboxed renderer.
+const Buffer = require('buffer').Buffer
+
+const typedArrays = {
+  Buffer,
+  ArrayBuffer,
+  Int8Array,
+  Uint8Array,
+  Uint8ClampedArray,
+  Int16Array,
+  Uint16Array,
+  Int32Array,
+  Uint32Array,
+  Float32Array,
+  Float64Array
+}
+
+function getType (value) {
+  for (const type of Object.keys(typedArrays)) {
+    if (value instanceof typedArrays[type]) {
+      return type
+    }
+  }
+  return null
+}
+
+exports.isBuffer = function (value) {
+  return ArrayBuffer.isView(value) || value instanceof ArrayBuffer
+}
+
+exports.bufferToMeta = function (value) {
+  const buffer = (value instanceof ArrayBuffer)
+    ? Buffer.from(value)
+    : Buffer.from(value.buffer, value.byteOffset, value.byteLength)
+
+  return {
+    type: getType(value),
+    data: buffer.toString('base64'),
+    length: value.length
+  }
+}
+
+exports.metaToBuffer = function (value) {
+  const constructor = typedArrays[value.type]
+  const data = Buffer.from(value.data, 'base64')
+
+  if (constructor === Buffer) {
+    return data
+  } else if (constructor === ArrayBuffer) {
+    return data.buffer
+  } else if (constructor) {
+    return new constructor(data.buffer, data.byteOffset, value.length)
+  } else {
+    return data
+  }
+}