dom/cache/ReadStream.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_cache_ReadStream_h
   8 #define mozilla_dom_cache_ReadStream_h
   9
  10 #include "mozilla/dom/SafeRefPtr.h"
  11 #include "mozilla/ipc/FileDescriptor.h"
  12 #include "mozilla/RefPtr.h"
  13 #include "nsCOMPtr.h"
  14 #include "nsID.h"
  15 #include "nsIInputStream.h"
  16 #include "nsISupportsImpl.h"
  17 #include "nsTArrayForwardDeclare.h"
  18
  19 namespace mozilla {
  20 class ErrorResult;
  21
  22 namespace dom::cache {
  23
  24 class CacheReadStream;
  25 class PCacheStreamControlParent;
  26
  27 // IID for the dom::cache::ReadStream interface
  28 #define NS_DOM_CACHE_READSTREAM_IID                  \
  29   {                                                  \
  30     0x8e5da7c9, 0x0940, 0x4f1d, {                    \
  31       0x97, 0x25, 0x5c, 0x59, 0x38, 0xdd, 0xb9, 0x9f \
  32     }                                                \
  33   }
  34
  35 // Custom stream class for Request and Response bodies being read from
  36 // a Cache.  The main purpose of this class is to report back to the
  37 // Cache's Manager when the stream is closed.  This allows the Cache to
  38 // accurately determine when the underlying body file can be deleted,
  39 // etc.
  40 //
  41 // The ReadStream class also provides us with a convenient QI'able
  42 // interface that we can use to pass additional meta-data with the
  43 // stream channel.  For example, Cache.put() can detect that the content
  44 // script is passing a Cache-originated-stream back into the Cache
  45 // again.  This enables certain optimizations.
  46 class ReadStream final : public nsIInputStream {
  47  public:
  48   // Interface that lets the StreamControl classes interact with
  49   // our private inner stream.
  50   class Controllable : public AtomicSafeRefCounted<Controllable> {
  51    public:
  52     virtual ~Controllable() = default;
  53
  54     // Closes the stream, notifies the stream control, and then forgets
  55     // the stream control.
  56     virtual void CloseStream() = 0;
  57
  58     // Closes the stream and then forgets the stream control.  Does not
  59     // notify.
  60     virtual void CloseStreamWithoutReporting() = 0;
  61
  62     virtual bool HasEverBeenRead() const = 0;
  63
  64     MOZ_DECLARE_REFCOUNTED_TYPENAME(ReadStream::Controllable);
  65   };
  66
  67   static already_AddRefed<ReadStream> Create(
  68       const Maybe<CacheReadStream>& aMaybeReadStream);
  69
  70   static already_AddRefed<ReadStream> Create(
  71       const CacheReadStream& aReadStream);
  72
  73   static already_AddRefed<ReadStream> Create(
  74       PCacheStreamControlParent* aControl, const nsID& aId,
  75       nsIInputStream* aStream);
  76
  77   void Serialize(Maybe<CacheReadStream>* aReadStreamOut, ErrorResult& aRv);
  78   void Serialize(CacheReadStream* aReadStreamOut, ErrorResult& aRv);
  79
  80  private:
  81   class Inner;
  82
  83   ~ReadStream();
  84
  85   // Hold a strong ref to an inner class that actually implements the
  86   // majority of the stream logic.  Before releasing this ref the outer
  87   // ReadStream guarantees it will call Close() on the inner stream.
  88   // This is essential for the inner stream to avoid dealing with the
  89   // implicit close that can happen when a stream is destroyed.
  90   SafeRefPtr<ReadStream::Inner> mInner;
  91
  92  public:
  93   explicit ReadStream(SafeRefPtr<ReadStream::Inner> aInner);
  94
  95   NS_DECLARE_STATIC_IID_ACCESSOR(NS_DOM_CACHE_READSTREAM_IID);
  96   NS_DECL_THREADSAFE_ISUPPORTS
  97   NS_DECL_NSIINPUTSTREAM
  98 };
  99
 100 NS_DEFINE_STATIC_IID_ACCESSOR(ReadStream, NS_DOM_CACHE_READSTREAM_IID);
 101
 102 }  // namespace dom::cache
 103 }  // namespace mozilla
 104
 105 #endif  // mozilla_dom_cache_ReadStream_h