Bug 1399466 - IPCBlobInputStream should not use STS to read from the remote Stream, but DOMFile thread instead, r=smaug

dom/file/ipc/IPCBlobInputStream.cpp

@@ -8,10 +8,11 @@
 #include "IPCBlobInputStreamChild.h"
 #include "IPCBlobInputStreamStorage.h"
 #include "mozilla/ipc/InputStreamParams.h"
+#include "IPCBlobInputStreamThread.h"
 #include "nsIAsyncInputStream.h"
-#include "nsIStreamTransportService.h"
-#include "nsITransport.h"
-#include "nsNetCID.h"
+#include "nsIAsyncOutputStream.h"
+#include "nsIPipe.h"
+#include "nsStreamUtils.h"
 #include "nsStringStream.h"
 #include "SlicedInputStream.h"
 
@@ -20,8 +21,6 @@ namespace dom {
 
 namespace {
 
-static NS_DEFINE_CID(kStreamTransportServiceCID, NS_STREAMTRANSPORTSERVICE_CID);
-
 class InputStreamCallbackRunnable final : public CancelableRunnable
 {
 public:
@@ -651,32 +650,25 @@ IPCBlobInputStream::EnsureAsyncRemoteStream()
 
   nsCOMPtr<nsIAsyncInputStream> asyncStream = do_QueryInterface(mRemoteStream);
   if (!asyncStream || !nonBlocking) {
-    nsCOMPtr<nsIStreamTransportService> sts =
-      do_GetService(kStreamTransportServiceCID, &rv);
+    // Let's make the stream async using the DOMFile thread.
+    nsCOMPtr<nsIAsyncInputStream> pipeIn;
+    nsCOMPtr<nsIAsyncOutputStream> pipeOut;
+    rv = NS_NewPipe2(getter_AddRefs(pipeIn),
+                     getter_AddRefs(pipeOut),
+                     true, true);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
 
-    nsCOMPtr<nsITransport> transport;
-    rv = sts->CreateInputTransport(mRemoteStream,
-                                   /* aStartOffset */ 0,
-                                   /* aReadLimit */ -1,
-                                   /* aCloseWhenDone */ true,
-                                   getter_AddRefs(transport));
+    nsCOMPtr<nsIEventTarget> target =
+      IPCBlobInputStreamThread::GetOrCreate()->EventTarget();
+    rv = NS_AsyncCopy(mRemoteStream, pipeOut, target,
+                      NS_ASYNCCOPY_VIA_WRITESEGMENTS);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
 
-    nsCOMPtr<nsIInputStream> wrapper;
-    rv = transport->OpenInputStream(/* aFlags */ 0,
-                                    /* aSegmentSize */ 0,
-                                    /* aSegmentCount */ 0,
-                                    getter_AddRefs(wrapper));
-    if (NS_WARN_IF(NS_FAILED(rv))) {
-      return rv;
-    }
-
-    asyncStream = do_QueryInterface(wrapper);
+    asyncStream = pipeIn;
   }
 
   MOZ_ASSERT(asyncStream);

dom/file/ipc/IPCBlobInputStreamThread.cpp

@@ -158,6 +158,12 @@ IPCBlobInputStreamThread::Initialize()
   }
 }
 
+nsIEventTarget*
+IPCBlobInputStreamThread::EventTarget() const
+{
+  return mThread;
+}
+
 NS_IMETHODIMP
 IPCBlobInputStreamThread::Observe(nsISupports* aSubject,
                                   const char* aTopic,

dom/file/ipc/IPCBlobInputStreamThread.h

@@ -34,6 +34,9 @@ public:
   void
   Initialize();
 
+  nsIEventTarget*
+  EventTarget() const;
+
 private:
   ~IPCBlobInputStreamThread() = default;