diff -r 000000000000 -r 6474c204b198 content/base/src/nsDOMBlobBuilder.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/base/src/nsDOMBlobBuilder.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,187 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDOMBlobBuilder_h
+#define nsDOMBlobBuilder_h
+
+#include "nsDOMFile.h"
+
+#include "mozilla/CheckedInt.h"
+#include "mozilla/Attributes.h"
+#include <algorithm>
+
+#define NS_DOMMULTIPARTBLOB_CID { 0x47bf0b43, 0xf37e, 0x49ef, \
+  { 0x81, 0xa0, 0x18, 0xba, 0xc0, 0x57, 0xb5, 0xcc } }
+#define NS_DOMMULTIPARTBLOB_CONTRACTID "@mozilla.org/dom/multipart-blob;1"
+
+#define NS_DOMMULTIPARTFILE_CID { 0xc3361f77, 0x60d1, 0x4ea9, \
+  { 0x94, 0x96, 0xdf, 0x5d, 0x6f, 0xcd, 0xd7, 0x8f } }
+#define NS_DOMMULTIPARTFILE_CONTRACTID "@mozilla.org/dom/multipart-file;1"
+
+class nsDOMMultipartFile : public nsDOMFile,
+                           public nsIJSNativeInitializer
+{
+public:
+  // Create as a file
+  nsDOMMultipartFile(nsTArray<nsCOMPtr<nsIDOMBlob> > aBlobs,
+                     const nsAString& aName,
+                     const nsAString& aContentType)
+    : nsDOMFile(aName, aContentType, UINT64_MAX),
+      mBlobs(aBlobs),
+      mIsFromNsiFile(false)
+  {
+  }
+
+  // Create as a blob
+  nsDOMMultipartFile(nsTArray<nsCOMPtr<nsIDOMBlob> >& aBlobs,
+                     const nsAString& aContentType)
+    : nsDOMFile(aContentType, UINT64_MAX),
+      mBlobs(aBlobs),
+      mIsFromNsiFile(false)
+  {
+  }
+
+  // Create as a file to be later initialized
+  nsDOMMultipartFile(const nsAString& aName)
+    : nsDOMFile(aName, EmptyString(), UINT64_MAX),
+      mIsFromNsiFile(false)
+  {
+  }
+
+  // Create as a blob to be later initialized
+  nsDOMMultipartFile()
+    : nsDOMFile(EmptyString(), UINT64_MAX),
+      mIsFromNsiFile(false)
+  {
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // nsIJSNativeInitializer
+  NS_IMETHOD Initialize(nsISupports* aOwner,
+                        JSContext* aCx,
+                        JSObject* aObj,
+                        const JS::CallArgs& aArgs) MOZ_OVERRIDE;
+
+  typedef nsIDOMBlob* (*UnwrapFuncPtr)(JSContext*, JSObject*);
+  nsresult InitBlob(JSContext* aCx,
+                    uint32_t aArgc,
+                    JS::Value* aArgv,
+                    UnwrapFuncPtr aUnwrapFunc);
+  nsresult InitFile(JSContext* aCx,
+                    uint32_t aArgc,
+                    JS::Value* aArgv);
+  nsresult InitChromeFile(JSContext* aCx,
+                          uint32_t aArgc,
+                          JS::Value* aArgv);
+
+  already_AddRefed<nsIDOMBlob>
+  CreateSlice(uint64_t aStart, uint64_t aLength, const nsAString& aContentType) MOZ_OVERRIDE;
+
+  NS_IMETHOD GetSize(uint64_t*) MOZ_OVERRIDE;
+  NS_IMETHOD GetInternalStream(nsIInputStream**) MOZ_OVERRIDE;
+
+  static nsresult
+  NewFile(const nsAString& aName, nsISupports* *aNewObject);
+
+  // DOMClassInfo constructor (for Blob([b1, "foo"], { type: "image/png" }))
+  static nsresult
+  NewBlob(nsISupports* *aNewObject);
+
+  // DOMClassInfo constructor (for File([b1, "foo"], { type: "image/png",
+  //                                                   name: "foo.png" }))
+  inline static nsresult
+  NewFile(nsISupports* *aNewObject)
+  {
+    // Initialization will set the filename, so we can pass in an empty string
+    // for now.
+    return NewFile(EmptyString(), aNewObject);
+  }
+
+  virtual const nsTArray<nsCOMPtr<nsIDOMBlob> >*
+  GetSubBlobs() const MOZ_OVERRIDE { return &mBlobs; }
+
+  NS_IMETHOD GetMozFullPathInternal(nsAString& aFullPath) MOZ_OVERRIDE;
+
+protected:
+  nsresult ParseBlobArrayArgument(JSContext* aCx, JS::Value& aValue,
+                                  bool aNativeEOL, UnwrapFuncPtr aUnwrapFunc);
+
+  nsTArray<nsCOMPtr<nsIDOMBlob> > mBlobs;
+  bool mIsFromNsiFile;
+};
+
+class BlobSet {
+public:
+  BlobSet()
+    : mData(nullptr), mDataLen(0), mDataBufferLen(0)
+  {}
+
+  nsresult AppendVoidPtr(const void* aData, uint32_t aLength);
+  nsresult AppendString(JSString* aString, bool nativeEOL, JSContext* aCx);
+  nsresult AppendBlob(nsIDOMBlob* aBlob);
+  nsresult AppendArrayBuffer(JSObject* aBuffer);
+  nsresult AppendBlobs(const nsTArray<nsCOMPtr<nsIDOMBlob> >& aBlob);
+
+  nsTArray<nsCOMPtr<nsIDOMBlob> >& GetBlobs() { Flush(); return mBlobs; }
+
+  already_AddRefed<nsIDOMBlob>
+  GetBlobInternal(const nsACString& aContentType)
+  {
+    nsCOMPtr<nsIDOMBlob> blob =
+      new nsDOMMultipartFile(GetBlobs(), NS_ConvertASCIItoUTF16(aContentType));
+    return blob.forget();
+  }
+
+protected:
+  bool ExpandBufferSize(uint64_t aSize)
+  {
+    using mozilla::CheckedUint32;
+
+    if (mDataBufferLen >= mDataLen + aSize) {
+      mDataLen += aSize;
+      return true;
+    }
+
+    // Start at 1 or we'll loop forever.
+    CheckedUint32 bufferLen =
+      std::max<uint32_t>(static_cast<uint32_t>(mDataBufferLen), 1);
+    while (bufferLen.isValid() && bufferLen.value() < mDataLen + aSize)
+      bufferLen *= 2;
+
+    if (!bufferLen.isValid())
+      return false;
+
+    void* data = moz_realloc(mData, bufferLen.value());
+    if (!data)
+      return false;
+
+    mData = data;
+    mDataBufferLen = bufferLen.value();
+    mDataLen += aSize;
+    return true;
+  }
+
+  void Flush() {
+    if (mData) {
+      // If we have some data, create a blob for it
+      // and put it on the stack
+
+      nsCOMPtr<nsIDOMBlob> blob =
+        new nsDOMMemoryFile(mData, mDataLen, EmptyString(), EmptyString());
+      mBlobs.AppendElement(blob);
+      mData = nullptr; // The nsDOMMemoryFile takes ownership of the buffer
+      mDataLen = 0;
+      mDataBufferLen = 0;
+    }
+  }
+
+  nsTArray<nsCOMPtr<nsIDOMBlob> > mBlobs;
+  void* mData;
+  uint64_t mDataLen;
+  uint64_t mDataBufferLen;
+};
+
+#endif