dynamiclibrary.cpp

Pegasus is an open-source implementationof the DMTF CIM and WBEM standards. It is designed to be por

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#include <Pegasus/Common/PegasusAssert.h>
#include "DynamicLibrary.h"

#if defined(PEGASUS_OS_TYPE_WINDOWS)
# include "DynamicLibraryWindows.cpp"
#elif defined(PEGASUS_OS_HPUX) && !defined(PEGASUS_HPUX_USE_DLOPEN)
# include "DynamicLibraryHPUX.cpp"
#elif defined(PEGASUS_OS_TYPE_UNIX) || defined(PEGASUS_OS_VMS)
# include "DynamicLibraryPOSIX.cpp"
#else
# error "Unsupported platform"
#endif

PEGASUS_NAMESPACE_BEGIN

DynamicLibrary::DynamicLibrary()
    : _handle(0),
      _referenceCount(0)
{
}

DynamicLibrary::DynamicLibrary(const DynamicLibrary& library)
    : _fileName(library._fileName),
      _handle(0),
      _referenceCount(0)
{
    // load the module again, if necessary. this effectively increments the
    // operating system's reference count for the module.
    if (library.isLoaded())
    {
        if (load())
        {
            _referenceCount = library._referenceCount;
        }
    }
}

DynamicLibrary::DynamicLibrary(const String& fileName)
    : _fileName(fileName),
      _handle(0),
      _referenceCount(0)
{
}

DynamicLibrary::~DynamicLibrary()
{
    // Unload the module, if necessary, to keep the operating system's
    // reference count accurate.  One call to _unload() takes care of it
    // no matter how high _referenceCount is.

    if (_referenceCount > 0)
    {
        PEGASUS_ASSERT(_handle != 0);
        _unload();
    }
}

DynamicLibrary& DynamicLibrary::operator=(const DynamicLibrary& library)
{
    if (this == &library)
    {
        return *this;
    }

    while (isLoaded())
    {
        unload();
    }

    _fileName = library._fileName;

    // load the module again, if necessary. this effectively increments the
    // operating system's reference count for the module.
    if (library.isLoaded())
    {
        if (load())
        {
            _referenceCount = library._referenceCount;
        }
    }

    return *this;
}

Boolean DynamicLibrary::isLoaded() const
{
    return _handle != 0;
}

Boolean DynamicLibrary::load()
{
    AutoMutex lock(_loadMutex);

    Boolean loaded = true;

    if (_referenceCount == 0)
    {
        PEGASUS_ASSERT(_handle == 0);
        loaded = _load();
    }

    if (loaded)
    {
        PEGASUS_ASSERT(_handle != 0);
        _referenceCount++;
    }

    return loaded;
}

const String& DynamicLibrary::getLoadErrorMessage() const
{
    return _loadErrorMessage;
}

void DynamicLibrary::unload()
{
    AutoMutex lock(_loadMutex);

    PEGASUS_ASSERT(_referenceCount > 0);
    PEGASUS_ASSERT(_handle != 0);

    _referenceCount--;

    if (_referenceCount == 0)
    {
        _unload();
        _handle = 0;
        _loadErrorMessage.clear();
    }
}

const String& DynamicLibrary::getFileName() const
{
    return _fileName;
}

PEGASUS_NAMESPACE_END