michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef mozilla_plugins_MiniShmBase_h
michael@0: #define mozilla_plugins_MiniShmBase_h
michael@0: 
michael@0: #include "base/basictypes.h"
michael@0: 
michael@0: #include "nsDebug.h"
michael@0: 
michael@0: #include <windows.h>
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace plugins {
michael@0: 
michael@0: /**
michael@0:  * This class is used to provide RAII semantics for mapped views.
michael@0:  * @see ScopedHandle
michael@0:  */
michael@0: class ScopedMappedFileView
michael@0: {
michael@0: public:
michael@0:   explicit
michael@0:   ScopedMappedFileView(LPVOID aView)
michael@0:     : mView(aView)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   ~ScopedMappedFileView()
michael@0:   {
michael@0:     Close();
michael@0:   }
michael@0: 
michael@0:   void
michael@0:   Close()
michael@0:   {
michael@0:     if (mView) {
michael@0:       ::UnmapViewOfFile(mView);
michael@0:       mView = nullptr;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   void
michael@0:   Set(LPVOID aView)
michael@0:   {
michael@0:     Close();
michael@0:     mView = aView;
michael@0:   }
michael@0: 
michael@0:   LPVOID
michael@0:   Get() const
michael@0:   {
michael@0:     return mView;
michael@0:   }
michael@0: 
michael@0:   LPVOID
michael@0:   Take()
michael@0:   {
michael@0:     LPVOID result = mView;
michael@0:     mView = nullptr;
michael@0:     return result;
michael@0:   }
michael@0: 
michael@0:   operator LPVOID()
michael@0:   {
michael@0:     return mView;
michael@0:   }
michael@0: 
michael@0:   bool
michael@0:   IsValid() const
michael@0:   {
michael@0:     return (mView);
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   DISALLOW_COPY_AND_ASSIGN(ScopedMappedFileView);
michael@0: 
michael@0:   LPVOID mView;
michael@0: };
michael@0: 
michael@0: class MiniShmBase;
michael@0: 
michael@0: class MiniShmObserver
michael@0: {
michael@0: public:
michael@0:   /**
michael@0:    * This function is called whenever there is a new shared memory request.
michael@0:    * @param aMiniShmObj MiniShmBase object that may be used to read and 
michael@0:    *                    write from shared memory.
michael@0:    */
michael@0:   virtual void OnMiniShmEvent(MiniShmBase *aMiniShmObj) = 0;
michael@0:   /**
michael@0:    * This function is called once when a MiniShmParent and a MiniShmChild
michael@0:    * object have successfully negotiated a connection.
michael@0:    *
michael@0:    * @param aMiniShmObj MiniShmBase object that may be used to read and 
michael@0:    *                    write from shared memory.
michael@0:    */
michael@0:   virtual void OnMiniShmConnect(MiniShmBase *aMiniShmObj) { }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Base class for MiniShm connections. This class defines the common 
michael@0:  * interfaces and code between parent and child.
michael@0:  */
michael@0: class MiniShmBase
michael@0: {
michael@0: public:
michael@0:   /**
michael@0:    * Obtains a writable pointer into shared memory of type T.
michael@0:    * typename T must be plain-old-data and contain an unsigned integral 
michael@0:    * member T::identifier that uniquely identifies T with respect to 
michael@0:    * other types used by the protocol being implemented.
michael@0:    *
michael@0:    * @param aPtr Pointer to receive the shared memory address.
michael@0:    *             This value is set if and only if the function 
michael@0:    *             succeeded.
michael@0:    * @return NS_OK if and only if aPtr was successfully obtained.
michael@0:    *         NS_ERROR_ILLEGAL_VALUE if type T is not valid for MiniShm.
michael@0:    *         NS_ERROR_NOT_INITIALIZED if there is no valid MiniShm connection.
michael@0:    *         NS_ERROR_NOT_AVAILABLE if the memory is not safe to write.
michael@0:    */
michael@0:   template<typename T> nsresult
michael@0:   GetWritePtr(T*& aPtr)
michael@0:   {
michael@0:     if (!mWriteHeader || !mGuard) {
michael@0:       return NS_ERROR_NOT_INITIALIZED;
michael@0:     }
michael@0:     if (sizeof(T) > mPayloadMaxLen ||
michael@0:         T::identifier <= RESERVED_CODE_LAST) {
michael@0:       return NS_ERROR_ILLEGAL_VALUE;
michael@0:     }
michael@0:     if (::WaitForSingleObject(mGuard, mTimeout) != WAIT_OBJECT_0) {
michael@0:       return NS_ERROR_NOT_AVAILABLE;
michael@0:     }
michael@0:     mWriteHeader->mId = T::identifier;
michael@0:     mWriteHeader->mPayloadLen = sizeof(T);
michael@0:     aPtr = reinterpret_cast<T*>(mWriteHeader + 1);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Obtains a readable pointer into shared memory of type T.
michael@0:    * typename T must be plain-old-data and contain an unsigned integral 
michael@0:    * member T::identifier that uniquely identifies T with respect to 
michael@0:    * other types used by the protocol being implemented.
michael@0:    *
michael@0:    * @param aPtr Pointer to receive the shared memory address.
michael@0:    *             This value is set if and only if the function 
michael@0:    *             succeeded.
michael@0:    * @return NS_OK if and only if aPtr was successfully obtained.
michael@0:    *         NS_ERROR_ILLEGAL_VALUE if type T is not valid for MiniShm or if
michael@0:    *                                type T does not match the type of the data
michael@0:    *                                stored in shared memory.
michael@0:    *         NS_ERROR_NOT_INITIALIZED if there is no valid MiniShm connection.
michael@0:    */
michael@0:   template<typename T> nsresult
michael@0:   GetReadPtr(const T*& aPtr)
michael@0:   {
michael@0:     if (!mReadHeader) {
michael@0:       return NS_ERROR_NOT_INITIALIZED;
michael@0:     }
michael@0:     if (mReadHeader->mId != T::identifier ||
michael@0:         sizeof(T) != mReadHeader->mPayloadLen) {
michael@0:       return NS_ERROR_ILLEGAL_VALUE;
michael@0:     }
michael@0:     aPtr = reinterpret_cast<const T*>(mReadHeader + 1);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Fires the peer's event causing its request handler to execute.
michael@0:    *
michael@0:    * @return Should return NS_OK if the send was successful.
michael@0:    */
michael@0:   virtual nsresult
michael@0:   Send() = 0;
michael@0: 
michael@0: protected:
michael@0:   /**
michael@0:    * MiniShm reserves some identifier codes for its own use. Any 
michael@0:    * identifiers used by MiniShm protocol implementations must be 
michael@0:    * greater than RESERVED_CODE_LAST.
michael@0:    */
michael@0:   enum ReservedCodes
michael@0:   {
michael@0:     RESERVED_CODE_INIT = 0,
michael@0:     RESERVED_CODE_INIT_COMPLETE = 1,
michael@0:     RESERVED_CODE_LAST = RESERVED_CODE_INIT_COMPLETE
michael@0:   };
michael@0: 
michael@0:   struct MiniShmHeader
michael@0:   {
michael@0:     unsigned int  mId;
michael@0:     unsigned int  mPayloadLen;
michael@0:   };
michael@0: 
michael@0:   struct MiniShmInit
michael@0:   {
michael@0:     enum identifier_t
michael@0:     {
michael@0:       identifier = RESERVED_CODE_INIT
michael@0:     };
michael@0:     HANDLE    mParentEvent;
michael@0:     HANDLE    mParentGuard;
michael@0:     HANDLE    mChildEvent;
michael@0:     HANDLE    mChildGuard;
michael@0:   };
michael@0: 
michael@0:   struct MiniShmInitComplete
michael@0:   {
michael@0:     enum identifier_t
michael@0:     {
michael@0:       identifier = RESERVED_CODE_INIT_COMPLETE
michael@0:     };
michael@0:     bool      mSucceeded;
michael@0:   };
michael@0: 
michael@0:   MiniShmBase()
michael@0:     : mObserver(nullptr),
michael@0:       mWriteHeader(nullptr),
michael@0:       mReadHeader(nullptr),
michael@0:       mPayloadMaxLen(0),
michael@0:       mGuard(nullptr),
michael@0:       mTimeout(INFINITE)
michael@0:   {
michael@0:   }
michael@0:   virtual ~MiniShmBase()
michael@0:   { }
michael@0: 
michael@0:   virtual void
michael@0:   OnEvent()
michael@0:   {
michael@0:     if (mObserver) {
michael@0:       mObserver->OnMiniShmEvent(this);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   virtual void
michael@0:   OnConnect()
michael@0:   {
michael@0:     if (mObserver) {
michael@0:       mObserver->OnMiniShmConnect(this);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   nsresult
michael@0:   SetView(LPVOID aView, const unsigned int aSize, bool aIsChild)
michael@0:   {
michael@0:     if (!aView || aSize <= 2 * sizeof(MiniShmHeader)) {
michael@0:       return NS_ERROR_ILLEGAL_VALUE;
michael@0:     }
michael@0:     // Divide the region into halves for parent and child
michael@0:     if (aIsChild) {
michael@0:       mReadHeader = static_cast<MiniShmHeader*>(aView);
michael@0:       mWriteHeader = reinterpret_cast<MiniShmHeader*>(static_cast<char*>(aView)
michael@0:                                                       + aSize / 2U);
michael@0:     } else {
michael@0:       mWriteHeader = static_cast<MiniShmHeader*>(aView);
michael@0:       mReadHeader = reinterpret_cast<MiniShmHeader*>(static_cast<char*>(aView)
michael@0:                                                      + aSize / 2U);
michael@0:     }
michael@0:     mPayloadMaxLen = aSize / 2U - sizeof(MiniShmHeader);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   nsresult
michael@0:   SetGuard(HANDLE aGuard, DWORD aTimeout)
michael@0:   {
michael@0:     if (!aGuard || !aTimeout) {
michael@0:       return NS_ERROR_ILLEGAL_VALUE;
michael@0:     }
michael@0:     mGuard = aGuard;
michael@0:     mTimeout = aTimeout;
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   inline void
michael@0:   SetObserver(MiniShmObserver *aObserver) { mObserver = aObserver; }
michael@0: 
michael@0:   /**
michael@0:    * Obtains a writable pointer into shared memory of type T. This version 
michael@0:    * differs from GetWritePtr in that it allows typename T to be one of 
michael@0:    * the private data structures declared in MiniShmBase.
michael@0:    *
michael@0:    * @param aPtr Pointer to receive the shared memory address.
michael@0:    *             This value is set if and only if the function 
michael@0:    *             succeeded.
michael@0:    * @return NS_OK if and only if aPtr was successfully obtained.
michael@0:    *         NS_ERROR_ILLEGAL_VALUE if type T not an internal MiniShm struct.
michael@0:    *         NS_ERROR_NOT_INITIALIZED if there is no valid MiniShm connection.
michael@0:    */
michael@0:   template<typename T> nsresult
michael@0:   GetWritePtrInternal(T*& aPtr)
michael@0:   {
michael@0:     if (!mWriteHeader) {
michael@0:       return NS_ERROR_NOT_INITIALIZED;
michael@0:     }
michael@0:     if (sizeof(T) > mPayloadMaxLen ||
michael@0:         T::identifier > RESERVED_CODE_LAST) {
michael@0:       return NS_ERROR_ILLEGAL_VALUE;
michael@0:     }
michael@0:     mWriteHeader->mId = T::identifier;
michael@0:     mWriteHeader->mPayloadLen = sizeof(T);
michael@0:     aPtr = reinterpret_cast<T*>(mWriteHeader + 1);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   static VOID CALLBACK
michael@0:   SOnEvent(PVOID aContext, BOOLEAN aIsTimer)
michael@0:   {
michael@0:     MiniShmBase* object = static_cast<MiniShmBase*>(aContext);
michael@0:     object->OnEvent();
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   MiniShmObserver*  mObserver;
michael@0:   MiniShmHeader*    mWriteHeader;
michael@0:   MiniShmHeader*    mReadHeader;
michael@0:   unsigned int      mPayloadMaxLen;
michael@0:   HANDLE            mGuard;
michael@0:   DWORD             mTimeout;
michael@0: 
michael@0:   DISALLOW_COPY_AND_ASSIGN(MiniShmBase);
michael@0: };
michael@0: 
michael@0: } // namespace plugins
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // mozilla_plugins_MiniShmBase_h
michael@0: