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_mscom_FastMarshaler_h
8 #define mozilla_mscom_FastMarshaler_h
9 
10 #include "mozilla/Atomics.h"
11 #include "mozilla/mscom/Aggregation.h"
12 #include "mozilla/RefPtr.h"
13 
14 #include <objidl.h>
15 
16 namespace mozilla {
17 namespace mscom {
18 
19 /**
20  * When we are marshaling to the parent process main thread, we want to turn
21  * off COM's ping functionality. That functionality is designed to free
22  * strong references held by defunct client processes. Since our content
23  * processes cannot outlive our parent process, we turn off pings when we know
24  * that the COM client is going to be our parent process. This provides a
25  * significant performance boost in a11y code due to large numbers of remote
26  * objects being created and destroyed within a short period of time.
27  */
28 class FastMarshaler final : public IMarshal {
29  public:
30   static HRESULT Create(IUnknown* aOuter, IUnknown** aOutMarshalerUnk);
31 
32   // IMarshal
33   STDMETHODIMP GetUnmarshalClass(REFIID riid, void* pv, DWORD dwDestContext,
34                                  void* pvDestContext, DWORD mshlflags,
35                                  CLSID* pCid) override;
36   STDMETHODIMP GetMarshalSizeMax(REFIID riid, void* pv, DWORD dwDestContext,
37                                  void* pvDestContext, DWORD mshlflags,
38                                  DWORD* pSize) override;
39   STDMETHODIMP MarshalInterface(IStream* pStm, REFIID riid, void* pv,
40                                 DWORD dwDestContext, void* pvDestContext,
41                                 DWORD mshlflags) override;
42   STDMETHODIMP UnmarshalInterface(IStream* pStm, REFIID riid,
43                                   void** ppv) override;
44   STDMETHODIMP ReleaseMarshalData(IStream* pStm) override;
45   STDMETHODIMP DisconnectObject(DWORD dwReserved) override;
46 
47  private:
48   FastMarshaler(IUnknown* aOuter, HRESULT* aResult);
49   ~FastMarshaler() = default;
50 
51   static DWORD GetMarshalFlags(DWORD aDestContext, DWORD aMshlFlags);
52 
53   Atomic<ULONG> mRefCnt;
54   IUnknown* mOuter;
55   RefPtr<IUnknown> mStdMarshalUnk;
56   IMarshal* mStdMarshalWeak;
57   DECLARE_AGGREGATABLE(FastMarshaler);
58 };
59 
60 }  // namespace mscom
61 }  // namespace mozilla
62 
63 #endif  // mozilla_mscom_FastMarshaler_h
64