DynamicLibrary.h

#pragma once

#include <string>
#include <vector>
#include <memory>

#if defined(WIN32)
const char* const MODULE_FILE_EXTENSION = ".dll";
#elif defined(POSIX)
const char* const MODULE_FILE_EXTENSION = ".so";
#endif

/** greebo: This file declares the classes encapsulating a dynamically linked library.
 *          Each DL class must define a FunctionPointer typedef and a findSymbol() method.
 *
 *  		The declaration is platform-specific, currently Win32 and POSIX are declared.
 */

/**
 * =============================== WIN32 ======================================
 */
#if defined(WIN32)

#include <windows.h>

namespace module
{

/** greebo: WIN32 DynamicLibrary. Loads a DLL given in the constructor.
 */
class DynamicLibrary
{
	// The full filename of this library
	std::wstring _name;

	// The library handle
	HMODULE _library;

public:
	// The win32 function pointer typedef for calling symbols
	typedef FARPROC FunctionPointer;

	// Constructor, pass the full filename to load this DLL
	DynamicLibrary(const std::string& filename);

	~DynamicLibrary();

	// Returns TRUE if the library load failed. (TODO: greebo: Remove this in favour of exceptions?)
	bool failed();

	/** greebo: The lookup method for symbols. Returns a platform-specific function
	 *          pointer that can be used to call the symbol.
	 */
	FunctionPointer findSymbol(const std::string& symbol);

	// Returns the filename of this module
	std::string getName() const;
};

} // namespace module

/**
 * =============================== POSIX ======================================
 */
#elif defined(POSIX)

#include <dlfcn.h>

namespace module
{

class DynamicLibrary
{
	// The full filename of this library
	std::string _name;

	// The handle for accessing the dynamic library
	void* _dlHandle;

public:
	// The posix function pointer typedef for calling symbols
	typedef int (* FunctionPointer)();

	// Constructor, pass the full filename to load this DLL
	DynamicLibrary(const std::string& filename);

	~DynamicLibrary();

	// Returns TRUE if the library load failed. (TODO: greebo: Remove this in favour of exceptions?)
	bool failed();

	/** greebo: The lookup method for symbols. Returns a platform-specific function
	 *          pointer that can be used to call the symbol.
	 */
	FunctionPointer findSymbol(const std::string& symbol);

	// Returns the filename of this module
	std::string getName() const;
};

} // namespace module

#else
#error "unsupported platform"
#endif

namespace module
{

// Shared ptr typedef
typedef std::shared_ptr<DynamicLibrary> DynamicLibraryPtr;

// A list of allocated libraries
typedef std::vector<DynamicLibraryPtr> DynamicLibraryList;

}