- Main Page
- Related Pages
- Modules
- Classes
- Files

# Semaphore.h

Go to the documentation of this file.

    00001 #ifndef FDO_SEMAPHORE
    00002 #define FDO_SEMAPHORE
    00003 //
    00004
    00005 //
    00006 // Copyright (C) 2004-2006  Autodesk, Inc.
    00007 //
    00008 // This library is free software; you can redistribute it and/or
    00009 // modify it under the terms of version 2.1 of the GNU Lesser
    00010 // General Public License as published by the Free Software Foundation.
    00011 //
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    00015 // Lesser General Public License for more details.
    00016 //
    00017 // You should have received a copy of the GNU Lesser General Public
    00018 // License along with this library; if not, write to the Free Software
    00019 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    00020 //
    00021
    00022 /// \cond DOXYGEN-IGNORE
    00023
    00024 /// \brief
    00025 /// FdoSemaphore is a semaphore class. It is used to prevent operations
    00026 /// from happening concurrently or re-entrantly. FdoSemaphore is not currently part
    00027 /// of the FDO API but can be added if there is a demand. It is a wrapper class around
    00028 /// a boolean semaphore.
    00029 ///
    00030 /// FdoSemaphore can be used to prevent a member function on another class from
    00031 /// being called re-entrantly for the same object (see FdoXmlReaderXrcs::Parse())
    00032 /// for an example. This can be done by declaring a FdoSemaphoreP, at the start of the
    00033 /// function, that takes a boolean member and an exception. The boolean member must initially
    00034 /// be false. When the FdoSemaphoreP is created, the boolean member is set to true. When
    00035 /// the function exits, FdoSemaphoreP goes out of scope and sets the boolean member back
    00036 /// to false. However, if the function is called a second time before the first
    00037 /// invokation finishes, the second FdoSemaphoreP created will detect that the boolean member
    00038 /// is true, and it will throw the given exception, thus rejecting the re-entrant
    00039 /// function call.
    00040 class FdoSemaphore : public FdoIDisposable
    00041 {
    00042 public:
    00043     /// \brief
    00044     /// Constructs a new semaphore.
    00045     /// \param semaphore
    00046     /// Input the semaphore switch. If true, then the
    00047     /// given exception is thrown. If false, then semaphore is set to true.
    00048     /// semaphore is set back to false when this object is deleted.
    00049     /// \param ex
    00050     /// Input the exception to throw when semaphore is true.
    00051     ///
    00052     /// \return
    00053     /// Returns FdoSemaphore
    00054     ///
    00055     static FdoSemaphore* Create( FdoBoolean& semaphore, FdoException* ex )
    00056     {
    00057         return new FdoSemaphore( semaphore, ex );
    00058     }
    00059
    00060 protected:
    00061     FdoSemaphore() {}
    00062     FdoSemaphore( bool& semaphore, FdoException* ex );
    00063     virtual ~FdoSemaphore();
    00064
    00065     virtual void Dispose()
    00066     {
    00067         delete this;
    00068     }
    00069
    00070 private:
    00071     /// Pointer to the bool semaphore, so that it can be reset on destruction
    00072     /// of this object.
    00073     FdoBoolean* mSemaphore;
    00074
    00075 };
    00076
    00077 /// \brief
    00078 /// FdoSemaphoreP is a FdoPtr on FdoSemaphore, provided for convenience.
    00079 typedef FdoPtr<FdoSemaphore> FdoSemaphoreP;
    00080
    00081 /// \endcond
    00082
    00083 #endif
    00084
    00085

Please send us your comment about this page