1 files changed, 57 insertions, 0 deletions
diff --git a/netwerk/base/nsPreloadedStream.h b/netwerk/base/nsPreloadedStream.h
new file mode 100644
index 0000000000..5c550b43e7
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+++ b/netwerk/base/nsPreloadedStream.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 4; 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/. */
+
+/**
+ * This class allows you to prefix an existing nsIAsyncInputStream
+ * with a preloaded block of data known at construction time by wrapping the
+ * two data sources into a new nsIAsyncInputStream. Readers of the new
+ * stream initially see the preloaded data and when that has been exhausted
+ * they automatically read from the wrapped stream.
+ *
+ * It is used by nsHttpConnection when it has over buffered while reading from
+ * the HTTP input socket and accidentally consumed data that belongs to
+ * a different protocol via the HTTP Upgrade mechanism. That over-buffered
+ * data is preloaded together with the input socket to form the new input socket
+ * given to the new protocol handler.
+ */
+
+#ifndef nsPreloadedStream_h__
+#define nsPreloadedStream_h__
+
+#include "nsIAsyncInputStream.h"
+#include "nsCOMPtr.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DataMutex.h"
+
+namespace mozilla {
+namespace net {
+
+class nsPreloadedStream final : public nsIAsyncInputStream,
+                                public nsIInputStreamCallback {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIINPUTSTREAM
+  NS_DECL_NSIASYNCINPUTSTREAM
+  NS_DECL_NSIINPUTSTREAMCALLBACK
+
+  nsPreloadedStream(nsIAsyncInputStream* aStream, const char* data,
+                    uint32_t datalen);
+
+ private:
+  ~nsPreloadedStream();
+
+  nsCOMPtr<nsIAsyncInputStream> mStream;
+
+  char* mBuf;
+  uint32_t mOffset;
+  uint32_t mLen;
+
+  DataMutex<nsCOMPtr<nsIInputStreamCallback>> mCallback;
+};
+
+}  // namespace net
+}  // namespace mozilla
+
+#endif