diff -r 000000000000 -r 6474c204b198 ipc/glue/InputStreamUtils.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/glue/InputStreamUtils.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,178 @@
+/* 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/. */
+
+#include "InputStreamUtils.h"
+
+#include "nsIIPCSerializableInputStream.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/dom/ipc/Blob.h"
+#include "nsComponentManagerUtils.h"
+#include "nsDebug.h"
+#include "nsID.h"
+#include "nsIDOMFile.h"
+#include "nsIXULRuntime.h"
+#include "nsMIMEInputStream.h"
+#include "nsMultiplexInputStream.h"
+#include "nsNetCID.h"
+#include "nsStringStream.h"
+#include "nsThreadUtils.h"
+#include "nsXULAppAPI.h"
+
+using mozilla::dom::BlobChild;
+using mozilla::dom::BlobParent;
+
+namespace {
+
+NS_DEFINE_CID(kStringInputStreamCID, NS_STRINGINPUTSTREAM_CID);
+NS_DEFINE_CID(kFileInputStreamCID, NS_LOCALFILEINPUTSTREAM_CID);
+NS_DEFINE_CID(kPartialFileInputStreamCID, NS_PARTIALLOCALFILEINPUTSTREAM_CID);
+NS_DEFINE_CID(kBufferedInputStreamCID, NS_BUFFEREDINPUTSTREAM_CID);
+NS_DEFINE_CID(kMIMEInputStreamCID, NS_MIMEINPUTSTREAM_CID);
+NS_DEFINE_CID(kMultiplexInputStreamCID, NS_MULTIPLEXINPUTSTREAM_CID);
+
+} // anonymous namespace
+
+namespace mozilla {
+namespace ipc {
+
+void
+SerializeInputStream(nsIInputStream* aInputStream,
+                     InputStreamParams& aParams,
+                     nsTArray<FileDescriptor>& aFileDescriptors)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aInputStream);
+
+  nsCOMPtr<nsIIPCSerializableInputStream> serializable =
+    do_QueryInterface(aInputStream);
+  if (!serializable) {
+    MOZ_CRASH("Input stream is not serializable!");
+  }
+
+  serializable->Serialize(aParams, aFileDescriptors);
+
+  if (aParams.type() == InputStreamParams::T__None) {
+    MOZ_CRASH("Serialize failed!");
+  }
+}
+
+void
+SerializeInputStream(nsIInputStream* aInputStream,
+                     OptionalInputStreamParams& aParams,
+                     nsTArray<FileDescriptor>& aFileDescriptors)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (aInputStream) {
+    InputStreamParams params;
+    SerializeInputStream(aInputStream, params, aFileDescriptors);
+    aParams = params;
+  }
+  else {
+    aParams = mozilla::void_t();
+  }
+}
+
+already_AddRefed<nsIInputStream>
+DeserializeInputStream(const InputStreamParams& aParams,
+                       const nsTArray<FileDescriptor>& aFileDescriptors)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIIPCSerializableInputStream> serializable;
+
+  switch (aParams.type()) {
+    case InputStreamParams::TStringInputStreamParams:
+      serializable = do_CreateInstance(kStringInputStreamCID);
+      break;
+
+    case InputStreamParams::TFileInputStreamParams:
+      serializable = do_CreateInstance(kFileInputStreamCID);
+      break;
+
+    case InputStreamParams::TPartialFileInputStreamParams:
+      serializable = do_CreateInstance(kPartialFileInputStreamCID);
+      break;
+
+    case InputStreamParams::TBufferedInputStreamParams:
+      serializable = do_CreateInstance(kBufferedInputStreamCID);
+      break;
+
+    case InputStreamParams::TMIMEInputStreamParams:
+      serializable = do_CreateInstance(kMIMEInputStreamCID);
+      break;
+
+    case InputStreamParams::TMultiplexInputStreamParams:
+      serializable = do_CreateInstance(kMultiplexInputStreamCID);
+      break;
+
+    // When the input stream already exists in this process, all we need to do
+    // is retrieve the original instead of sending any data over the wire.
+    case InputStreamParams::TRemoteInputStreamParams: {
+      nsCOMPtr<nsIDOMBlob> domBlob;
+      const RemoteInputStreamParams& params =
+          aParams.get_RemoteInputStreamParams();
+
+      domBlob = params.remoteBlobParent() ?
+          static_cast<BlobParent*>(params.remoteBlobParent())->GetBlob() :
+          static_cast<BlobChild*>(params.remoteBlobChild())->GetBlob();
+
+      MOZ_ASSERT(domBlob, "Invalid blob contents");
+
+      // If fetching the internal stream fails, we ignore it and return a
+      // null stream.
+      nsCOMPtr<nsIInputStream> stream;
+      nsresult rv = domBlob->GetInternalStream(getter_AddRefs(stream));
+      if (NS_FAILED(rv) || !stream) {
+        NS_WARNING("Couldn't obtain a valid stream from the blob");
+      }
+      return stream.forget();
+    }
+
+    default:
+      MOZ_ASSERT(false, "Unknown params!");
+      return nullptr;
+  }
+
+  MOZ_ASSERT(serializable);
+
+  if (!serializable->Deserialize(aParams, aFileDescriptors)) {
+    MOZ_ASSERT(false, "Deserialize failed!");
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIInputStream> stream = do_QueryInterface(serializable);
+  MOZ_ASSERT(stream);
+
+  return stream.forget();
+}
+
+already_AddRefed<nsIInputStream>
+DeserializeInputStream(const OptionalInputStreamParams& aParams,
+                       const nsTArray<FileDescriptor>& aFileDescriptors)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIInputStream> stream;
+
+  switch (aParams.type()) {
+    case OptionalInputStreamParams::Tvoid_t:
+      // Leave stream null.
+      break;
+
+    case OptionalInputStreamParams::TInputStreamParams:
+      stream = DeserializeInputStream(aParams.get_InputStreamParams(),
+                                      aFileDescriptors);
+      break;
+
+    default:
+      MOZ_ASSERT(false, "Unknown params!");
+  }
+
+  return stream.forget();
+}
+
+} // namespace ipc
+} // namespace mozilla