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0ad/source/ps/DllLoader.h

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C++

/* Copyright (C) 2011 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_DLLLOADER
#define INCLUDED_DLLLOADER
#include "ps/Errors.h"
ERROR_GROUP(DllLoader);
ERROR_TYPE(DllLoader, DllNotLoaded);
ERROR_TYPE(DllLoader, SymbolNotFound);
class DllLoader
{
public:
/**
* Prepare the DLL loader. Does no actual work.
*
* @param name base name of the library (from which we'll derive
* "name.dll", "libname_dbg.so", etc). Pointer must remain valid for
* this object's lifetime (which is fine if you just use a string literal).
*/
DllLoader(const char* name);
~DllLoader();
/**
* Attempt to load and initialise the library, if not already. Can be harmlessly
* called multiple times. Returns false if unsuccessful.
*/
bool LoadDLL();
/**
* Check whether the library has been loaded successfully. Returns false
* before {@link #LoadDLL} has been called; otherwise returns the same as
* LoadDLL did.
*/
bool IsLoaded() const;
/**
* Unload the library, if it has been loaded already. (Usually not needed,
* since the destructor will unload it.)
*/
void Unload();
/**
* Attempt to load a named symbol from the library. If {@link #IsLoaded} is
* false, throws PSERROR_DllLoader_DllNotLoaded. If it cannot load the
* symbol, throws PSERROR_DllLoader_SymbolNotFound. In both cases, sets fptr
* to NULL. Otherwise, fptr is set to point to the loaded function.
*
* @throws PSERROR_DllLoader
*/
template <typename T>
void LoadSymbol(const char* name, T& fptr) const;
/**
* Override the build-time setting of the directory to search for libraries.
*/
static void OverrideLibdir(const char* libdir);
private:
// Typeless version - the public LoadSymbol hides the slightly ugly
// casting from users.
void LoadSymbolInternal(const char* name, void** fptr) const;
const char* m_Name;
void* m_Handle;
};
template <typename T>
void DllLoader::LoadSymbol(const char* name, T& fptr) const
{
LoadSymbolInternal(name, (void**)&fptr);
}
#endif // INCLUDED_DLLLOADER