netwerk/base/nsPreloadedStream.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /**
   7  * This class allows you to prefix an existing nsIAsyncInputStream
   8  * with a preloaded block of data known at construction time by wrapping the
   9  * two data sources into a new nsIAsyncInputStream. Readers of the new
  10  * stream initially see the preloaded data and when that has been exhausted
  11  * they automatically read from the wrapped stream.
  12  *
  13  * It is used by nsHttpConnection when it has over buffered while reading from
  14  * the HTTP input socket and accidentally consumed data that belongs to
  15  * a different protocol via the HTTP Upgrade mechanism. That over-buffered
  16  * data is preloaded together with the input socket to form the new input socket
  17  * given to the new protocol handler.
  18  */
  19
  20 #ifndef nsPreloadedStream_h__
  21 #define nsPreloadedStream_h__
  22
  23 #include "nsIAsyncInputStream.h"
  24 #include "nsCOMPtr.h"
  25 #include "mozilla/Attributes.h"
  26 #include "mozilla/DataMutex.h"
  27
  28 namespace mozilla {
  29 namespace net {
  30
  31 class nsPreloadedStream final : public nsIAsyncInputStream,
  32                                 public nsIInputStreamCallback {
  33  public:
  34   NS_DECL_THREADSAFE_ISUPPORTS
  35   NS_DECL_NSIINPUTSTREAM
  36   NS_DECL_NSIASYNCINPUTSTREAM
  37   NS_DECL_NSIINPUTSTREAMCALLBACK
  38
  39   nsPreloadedStream(nsIAsyncInputStream* aStream, const char* data,
  40                     uint32_t datalen);
  41
  42  private:
  43   ~nsPreloadedStream();
  44
  45   nsCOMPtr<nsIAsyncInputStream> mStream;
  46
  47   char* mBuf;
  48   uint32_t mOffset;
  49   uint32_t mLen;
  50
  51   DataMutex<nsCOMPtr<nsIInputStreamCallback>> mCallback;
  52 };
  53
  54 }  // namespace net
  55 }  // namespace mozilla
  56
  57 #endif