// Copyright (C) 2003-2008 Dolphin Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#include <string.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <dlfcn.h>
#include <stdio.h>
#endif

#include "Common.h"
#include "StringUtil.h"
#include "DynamicLibrary.h"
#include "../../Core/Src/PowerPC/PowerPC.h"

DynamicLibrary::DynamicLibrary()
{
	library = 0;
}


std::string GetLastErrorAsString()
{
#ifdef _WIN32
        LPVOID lpMsgBuf = 0;
	DWORD error = GetLastError();
	FormatMessage( 
		FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
		NULL,
		error,
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
		(LPTSTR) &lpMsgBuf,
		0, NULL);
	std::string s;
	if (lpMsgBuf)
	{
		s = ((char *)lpMsgBuf);
		LocalFree(lpMsgBuf);
	} else {
		s = StringFromFormat("(unknown error %08x)", error);
	}
	return s;
#else
        static std::string errstr;
        char *tmp = dlerror();
        if (tmp)
            errstr = tmp;
        
        return errstr;
#endif
}


// ------------------------------------------------------------------
/* Loading means loading the dll with LoadLibrary() to get an instance to the dll.
   This is done when Dolphin is started to determine which dlls are good, and
   before opening the Config and Debugging windows from Plugin.cpp and
   before opening the dll for running the emulation in Video_...cpp in Core. */
// -----------------------
int DynamicLibrary::Load(const char* filename)
{
	if (!filename || strlen(filename) == 0)
	{
		LOG(MASTER_LOG, "Missing filename of dynamic library to load");
                PanicAlert("Missing filename of dynamic library to load");
		return 0;
	}
	LOG(MASTER_LOG, "Trying to load library %s", filename);

	if (IsLoaded())
	{
		LOG(MASTER_LOG, "Trying to load already loaded library %s", filename);
		return 2;
	}

#ifdef _WIN32
	library = LoadLibrary(filename);
#else
	library = dlopen(filename, RTLD_NOW | RTLD_LOCAL);
#endif
        
	if (!library) {
		LOG(MASTER_LOG, "Error loading DLL %s: %s", filename, GetLastErrorAsString().c_str());
		PanicAlert("Error loading DLL %s: %s\n", filename, GetLastErrorAsString().c_str());
		return 0;
	}

	library_file = filename;
	return 1;
}


int DynamicLibrary::Unload()
{
    int retval;
    if (!IsLoaded()) {
        LOG(MASTER_LOG, "Error unloading DLL %s: not loaded", library_file.c_str());
        PanicAlert("Error unloading DLL %s: not loaded", library_file.c_str());
        return 0;
    }

        
#ifdef _WIN32
	/* TEMPORARY SOLUTION: To prevent that Dolphin hangs when a game is stopped
	   or when we try to close Dolphin. It's possible that it only occur when we render
	   to the main window. And sometimes FreeLibrary works without any problem, so
	   don't remove this just because it doesn't hang once. I could not find the
	   actual cause of it. */
    if( ! (library_file.find("OGL.") != std::string::npos) && !PowerPC::CPU_POWERDOWN)
        retval = FreeLibrary(library);
#else
    retval = dlclose(library);
#endif
    if (!retval) {
        LOG(MASTER_LOG, "Error unloading DLL %s: %s", library_file.c_str(),
            GetLastErrorAsString().c_str());
        PanicAlert("Error unloading DLL %s: %s", library_file.c_str(),
                   GetLastErrorAsString().c_str());
    }
    library = 0;
    return retval;
}


void* DynamicLibrary::Get(const char* funcname) const
{
	void* retval;
	if (!library)
	{
            LOG(MASTER_LOG, "Can't find function %s - Library not loaded.");
            PanicAlert("Can't find function %s - Library not loaded.");
	}
#ifdef _WIN32
	retval = GetProcAddress(library, funcname);
#else
	retval = dlsym(library, funcname);
#endif

	if (!retval) {
            LOG(MASTER_LOG, "Symbol %s missing in %s (error: %s)\n", funcname, library_file.c_str(), GetLastErrorAsString().c_str());
            PanicAlert("Symbol %s missing in %s (error: %s)\n", funcname, library_file.c_str(), GetLastErrorAsString().c_str());
	}

	return retval;
}