//%2005////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
// Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
// Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation, The Open Group.
// Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.
// Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.;
// EMC Corporation; VERITAS Software Corporation; The Open Group.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//==============================================================================
//
// Author: Chip Vincent (cvincent@us.ibm.com)
//
// Modified By:
//
//%/////////////////////////////////////////////////////////////////////////////

#include "DynamicLibrary.h"

#include <Pegasus/Common/IPC.h>
#include <Pegasus/Common/ArrayInternal.h>
#include <Pegasus/Common/Pair.h>

#include <dl.h>

PEGASUS_NAMESPACE_BEGIN

// the HPUX dynamic library load and unload routines do not keep a reference count.
// this implies that if a library were loaded multiple times, a single unload will
// release the library from the process thereby potentially leaving dangling
// references behind. this is a tenative implementation that encapsulates this
// behavior from users of the DynamicLibrary object. the goal release the library
// only after an equal number of loads and unloads have occured.

static Array<Pair<DynamicLibrary::LIBRARY_HANDLE, AtomicInt> > _references;

Uint32 _increment_handle(DynamicLibrary::LIBRARY_HANDLE handle)
{
    // scoped mutex

    // seek and increment
    for(Uint32 i = 0, n = _references.size(); i < n; i++)
    {
        if(handle == _references[i].first)
        {
            Uint32 n = (_references[i].second+=1).value();

            return(n);
        }
    }

    // not found, append and set at 1
    _references.append(Pair<DynamicLibrary::LIBRARY_HANDLE, AtomicInt>(handle, 1));

    return(1);
}

Uint32 _decrement_handle(DynamicLibrary::LIBRARY_HANDLE handle)
{
    // scoped mutex

    // seek and decrement
    for(Uint32 i = 0, n = _references.size(); i < n; i++)
    {
        if(handle == _references[i].first)
        {
            Uint32 n = (_references[i].second-=1).value();

            if(n == 0)
            {
                _references.remove(i);
            }

            return(n);
        }
    }

    // not found, must be 0
    return(0);
}

Boolean DynamicLibrary::load(void)
{
    // ensure the module is not already loaded
    PEGASUS_ASSERT(isLoaded() == false);

    CString cstr = _fileName.getCString();

    //_handle = shl_load(cstr, BIND_IMMEDIATE | DYNAMIC_PATH | BIND_VERBOSE, 0L);
    _handle = shl_load(cstr, BIND_IMMEDIATE | DYNAMIC_PATH, 0L);

    // increment handle if valid
    if(_handle == 0)
    {
        _increment_handle(_handle);
    }

    return(isLoaded());
}

Boolean DynamicLibrary::unload(void)
{
    // ensure the module is loaded
    PEGASUS_ASSERT(isLoaded() == true);

    // decrement handle is valid and release the library only if the handle reference count is 0
    if((_handle != 0) && (_decrement_handle(_handle) == 0))
    {
        shl_unload(reinterpret_cast<shl_t>(_handle));
    }

    _handle = 0;

    return(isLoaded());
}

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

DynamicLibrary::LIBRARY_SYMBOL DynamicLibrary::getSymbol(const String & symbolName)
{
    LIBRARY_SYMBOL func = 0;

    if(isLoaded())
    {
        CString cstr = symbolName.getCString();

        if(shl_findsym((shl_t *)&_handle, cstr, TYPE_UNDEFINED, &func) == 0)
        {
            return(func);
        }

        // NOTE: should the underscore be prepended by the caller or should
        // this be a compile time option?

        cstr = String(String("_") + symbolName).getCString();

        if(shl_findsym((shl_t *)_handle, cstr, TYPE_UNDEFINED, &func) == 0)
        {
            return(func);
        }
    }

    return(0);
}

PEGASUS_NAMESPACE_END