Bug 1312412 - Introducing BlobImplString, r=smaug

dom/base/File.cpp

@@ -188,6 +188,16 @@ Blob::Create(nsISupports* aParent, const nsAString& aContentType,
   return blob.forget();
 }
 
+/* static */ already_AddRefed<Blob>
+Blob::CreateStringBlob(nsISupports* aParent, const nsACString& aData,
+                       const nsAString& aContentType)
+{
+  RefPtr<Blob> blob = Blob::Create(aParent,
+    new BlobImplString(aData, aContentType));
+  MOZ_ASSERT(!blob->mImpl->IsFile());
+  return blob.forget();
+}
+
 /* static */ already_AddRefed<Blob>
 Blob::CreateMemoryBlob(nsISupports* aParent, void* aMemoryBuffer,
                        uint64_t aLength, const nsAString& aContentType)
@@ -1038,6 +1048,28 @@ EmptyBlobImpl::GetInternalStream(nsIInputStream** aStream,
   }
 }
 
+////////////////////////////////////////////////////////////////////////////
+// BlobImplString implementation
+
+NS_IMPL_ISUPPORTS_INHERITED0(BlobImplString, BlobImpl)
+
+already_AddRefed<BlobImpl>
+BlobImplString::CreateSlice(uint64_t aStart, uint64_t aLength,
+                            const nsAString& aContentType,
+                            ErrorResult& aRv)
+{
+  RefPtr<BlobImpl> impl =
+    new BlobImplString(Substring(mData, aStart, aLength),
+                       aContentType);
+  return impl.forget();
+}
+
+void
+BlobImplString::GetInternalStream(nsIInputStream** aStream, ErrorResult& aRv)
+{
+  aRv = NS_NewCStringInputStream(aStream, mData);
+}
+
 ////////////////////////////////////////////////////////////////////////////
 // BlobImplMemory implementation
 

dom/base/File.h

@@ -71,6 +71,10 @@ public:
   Create(nsISupports* aParent, const nsAString& aContentType, uint64_t aStart,
          uint64_t aLength);
 
+  static already_AddRefed<Blob>
+  CreateStringBlob(nsISupports* aParent, const nsACString& aData,
+                   const nsAString& aContentType);
+
   // The returned Blob takes ownership of aMemoryBuffer. aMemoryBuffer will be
   // freed by free so it must be allocated by malloc or something
   // compatible with it.
@@ -520,6 +524,28 @@ protected:
   const uint64_t mSerialNumber;
 };
 
+class BlobImplString final : public BlobImplBase
+{
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  BlobImplString(const nsACString& aData, const nsAString& aContentType)
+    : BlobImplBase(aContentType, aData.Length())
+    , mData(aData)
+  {}
+
+  virtual void GetInternalStream(nsIInputStream** aStream,
+                                 ErrorResult& aRv) override;
+
+  virtual already_AddRefed<BlobImpl>
+  CreateSlice(uint64_t aStart, uint64_t aLength,
+              const nsAString& aContentType, ErrorResult& aRv) override;
+
+private:
+  ~BlobImplString() {}
+
+  nsCString mData;
+};
 /**
  * This class may be used off the main thread, and in particular, its
  * constructor and destructor may not run on the same thread.  Be careful!

dom/base/WebSocket.cpp

@@ -1973,9 +1973,14 @@ WebSocket::CreateAndDispatchMessageEvent(const nsACString& aData,
     if (mBinaryType == dom::BinaryType::Blob) {
       messageType = nsIWebSocketEventListener::TYPE_BLOB;
 
-      nsresult rv = nsContentUtils::CreateBlobBuffer(cx, GetOwner(), aData,
-                                                     &jsData);
-      NS_ENSURE_SUCCESS(rv, rv);
+      RefPtr<Blob> blob =
+        Blob::CreateStringBlob(GetOwner(), aData, EmptyString());
+      MOZ_ASSERT(blob);
+
+      if (!ToJSValue(cx, blob, &jsData)) {
+        return NS_ERROR_FAILURE;
+      }
+
     } else if (mBinaryType == dom::BinaryType::Arraybuffer) {
       messageType = nsIWebSocketEventListener::TYPE_ARRAYBUFFER;
 

dom/base/nsContentUtils.cpp

@@ -6248,32 +6248,6 @@ nsContentUtils::CreateArrayBuffer(JSContext *aCx, const nsACString& aData,
   return NS_OK;
 }
 
-// Initial implementation: only stores to RAM, not file
-// TODO: bug 704447: large file support
-nsresult
-nsContentUtils::CreateBlobBuffer(JSContext* aCx,
-                                 nsISupports* aParent,
-                                 const nsACString& aData,
-                                 JS::MutableHandle<JS::Value> aBlob)
-{
-  uint32_t blobLen = aData.Length();
-  void* blobData = malloc(blobLen);
-  RefPtr<Blob> blob;
-  if (blobData) {
-    memcpy(blobData, aData.BeginReading(), blobLen);
-    blob = mozilla::dom::Blob::CreateMemoryBlob(aParent, blobData, blobLen,
-                                                EmptyString());
-  } else {
-    return NS_ERROR_OUT_OF_MEMORY;
-  }
-
-  if (!ToJSValue(aCx, blob, aBlob)) {
-    return NS_ERROR_FAILURE;
-  }
-
-  return NS_OK;
-}
-
 void
 nsContentUtils::StripNullChars(const nsAString& aInStr, nsAString& aOutStr)
 {

dom/base/nsContentUtils.h

@@ -1863,11 +1863,6 @@ public:
   static nsresult CreateArrayBuffer(JSContext *aCx, const nsACString& aData,
                                     JSObject** aResult);
 
-  static nsresult CreateBlobBuffer(JSContext* aCx,
-                                   nsISupports* aParent,
-                                   const nsACString& aData,
-                                   JS::MutableHandle<JS::Value> aBlob);
-
   static void StripNullChars(const nsAString& aInStr, nsAString& aOutStr);
 
   /**

dom/base/nsDOMDataChannel.cpp

@@ -395,8 +395,13 @@ nsDOMDataChannel::DoOnMessageAvailable(const nsACString& aData,
 
   if (aBinary) {
     if (mBinaryType == DC_BINARY_TYPE_BLOB) {
-      rv = nsContentUtils::CreateBlobBuffer(cx, GetOwner(), aData, &jsData);
-      NS_ENSURE_SUCCESS(rv, rv);
+      RefPtr<Blob> blob =
+        Blob::CreateStringBlob(GetOwner(), aData, EmptyString());
+      MOZ_ASSERT(blob);
+
+      if (!ToJSValue(cx, blob, &jsData)) {
+        return NS_ERROR_FAILURE;
+      }
     } else if (mBinaryType == DC_BINARY_TYPE_ARRAYBUFFER) {
       JS::Rooted<JSObject*> arrayBuf(cx);
       rv = nsContentUtils::CreateArrayBuffer(cx, aData, arrayBuf.address());

dom/presentation/PresentationConnection.cpp

@@ -504,9 +504,12 @@ PresentationConnection::DoReceiveMessage(const nsACString& aData, bool aIsBinary
   nsresult rv;
   if (aIsBinary) {
     if (mBinaryType == PresentationConnectionBinaryType::Blob) {
-      rv = nsContentUtils::CreateBlobBuffer(cx, GetOwner(), aData, &jsData);
-      if (NS_WARN_IF(NS_FAILED(rv))) {
-        return rv;
+      RefPtr<Blob> blob =
+        Blob::CreateStringBlob(GetOwner(), aData, EmptyString());
+      MOZ_ASSERT(blob);
+
+      if (!ToJSValue(cx, blob, &jsData)) {
+        return NS_ERROR_FAILURE;
       }
     } else if (mBinaryType == PresentationConnectionBinaryType::Arraybuffer) {
       JS::Rooted<JSObject*> arrayBuf(cx);