target_link_libraries(openttd_lib ${CMAKE_DL_LIBS})

    library_loader.h

/*

 * This file is part of OpenTTD.

 * OpenTTD 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.

 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.

 */

/** @file library_loader.h Functions/types related to loading libraries dynamically. */

#ifndef LIBRARY_LOADER_H

#define LIBRARY_LOADER_H

class LibraryLoader {

public:

	/**

	 * A function loaded from a library.

	 *

	 * Will automatically cast to the correct function pointer type on retrieval.

	 */

	class Function {

	public:

		explicit Function(void *p) : p(p) {}

		template <typename T, typename = std::enable_if_t<std::is_function_v<T>>>

		operator T *() const

		{

			return reinterpret_cast<T *>(this->p);

		}

	private:

		void *p;

	};

	/**

	 * Load a library with the given filename.

	 */

	explicit LibraryLoader(const std::string &filename)

	{

		this->handle = this->OpenLibrary(filename);

	}

	/**

	 * Close the library.

	 */

	~LibraryLoader()

	{

		if (this->handle != nullptr) {

			this->CloseLibrary();

		}

	}

	/**

	 * Check whether an error occurred while loading the library or a function.

	 *

	 * @return Whether an error occurred.

	 */

	bool HasError()

	{

		return this->error.has_value();

	}

	/**

	 * Get the last error that occurred while loading the library or a function.

	 *

	 * @return The error message.

	 */

	std::string GetLastError()

	{

		return this->error.value_or("No error");

	}

	/**

	 * Get a function from a loaded library.

	 *

	 * @param symbol_name The name of the function to get.

	 * @return The function. Check HasError() before using.

	 */

	Function GetFunction(const std::string &symbol_name)

	{

		if (this->error.has_value()) return Function(nullptr);

		return Function(this->GetSymbol(symbol_name));

	}

private:

	/**

	 * Open the library with the given filename.

	 *

	 * Should set error if any error occurred.

	 *

	 * @param filename The filename of the library to open.

	 */

	void *OpenLibrary(const std::string &filename);

	/**

	 * Close the library.

	 */

	void CloseLibrary();

	/**

	 * Get a symbol from the library.

	 *

	 * Should set error if any error occurred.

	 *

	 * @param symbol_name The name of the symbol to get.

	 */

	void *GetSymbol(const std::string &symbol_name);

	std::optional<std::string> error = {}; ///< The last error that occurred, if set.

	void *handle = nullptr; ///< Handle to the library.

};

#endif /* LIBRARY_LOADER_H */

    library_loader_unix.cpp

/*

 * This file is part of OpenTTD.

 * OpenTTD 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.

 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.

 */

/** @file library_loader_unix.cpp Implementation of the LibraryLoader for Linux / MacOS */

#include "../../stdafx.h"

#include <dlfcn.h>

#include "../../library_loader.h"

#include "../../safeguards.h"

/* Emscripten cannot dynamically load other files. */

#if defined(__EMSCRIPTEN__)

void *LibraryLoader::OpenLibrary(const std::string &)

{

	this->error = "Dynamic loading is not supported on this platform.";

	return nullptr;

}

void LibraryLoader::CloseLibrary()

{

}

void *LibraryLoader::GetSymbol(const std::string &)

{

	this->error = "Dynamic loading is not supported on this platform.";

	return nullptr;

}

#else

void *LibraryLoader::OpenLibrary(const std::string &filename)

{

	void *h = dlopen(filename.c_str(), RTLD_NOW | RTLD_LOCAL);

	if (h == nullptr) {

		this->error = dlerror();

	}

	return h;

}

void LibraryLoader::CloseLibrary()

{

	dlclose(this->handle);

}

void *LibraryLoader::GetSymbol(const std::string &symbol_name)

{

	void *p = dlsym(this->handle, symbol_name.c_str());

	if (p == nullptr) {

		this->error = dlerror();

	}

	return p;

}

#endif /* __EMSCRIPTEN__ */

    library_loader_win.cpp

#include "../../library_loader.h"

	LibraryLoader dbghelp("dbghelp.dll");

		dbghelp.GetFunction("SymInitialize"),

		dbghelp.GetFunction("SymSetOptions"),

		dbghelp.GetFunction("SymCleanup"),

		dbghelp.GetFunction("StackWalk64"),

		dbghelp.GetFunction("SymFunctionTableAccess64"),

		dbghelp.GetFunction("SymGetModuleBase64"),

		dbghelp.GetFunction("SymGetModuleInfo64"),

		dbghelp.GetFunction("SymGetSymFromAddr64"),

		dbghelp.GetFunction("SymGetLineFromAddr64"),

	if (!dbghelp.HasError()) {

#include "../../fontdetection.h"

#include "../../library_loader.h"

				static LibraryLoader _gdi32("gdi32.dll");

				static PFNGETFONTRESOURCEINFO GetFontResourceInfo = _gdi32.GetFunction("GetFontResourceInfoW");

#include <windows.h>

/*

 * This file is part of OpenTTD.

 * OpenTTD 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.

 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.

 */

/** @file library_loader_win.cpp Implementation of the LibraryLoader for Windows */

#include "../../stdafx.h"

#include <windows.h>

#include "../../library_loader.h"

#include "../../safeguards.h"

static std::string GetLoadError()

{

	auto error_code = GetLastError();

	char buffer[512];

	if (FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr, error_code,

		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, sizeof(buffer), nullptr) == 0) {

		return fmt::format("Unknown error {}", error_code);

	}

	return buffer;

}

void *LibraryLoader::OpenLibrary(const std::string &filename)

{

	void *h = ::LoadLibraryW(OTTD2FS(filename).c_str());

	if (h == nullptr) {

		this->error = GetLoadError();

	}

	return h;

}

void LibraryLoader::CloseLibrary()

{

	HMODULE handle = static_cast<HMODULE>(this->handle);

	::FreeLibrary(handle);

}

void *LibraryLoader::GetSymbol(const std::string &symbol_name)

{

	HMODULE handle = static_cast<HMODULE>(this->handle);

	void *p = reinterpret_cast<void *>(::GetProcAddress(handle, symbol_name.c_str()));

	if (p == nullptr) {

		this->error = GetLoadError();

	}

	return p;

}

#include "../../library_loader.h"

		static LibraryLoader _kernel32("Kernel32.dll");

		_CompareStringEx = _kernel32.GetFunction("CompareStringEx");

		static LibraryLoader _kernel32("Kernel32.dll");

		_FindNLSStringEx = _kernel32.GetFunction("FindNLSStringEx");

#include "../library_loader.h"

		static LibraryLoader _user32("user32.dll");

		static LibraryLoader _shcore("shcore.dll");

		_GetDpiForWindow = _user32.GetFunction("GetDpiForWindow");

		_GetDpiForSystem = _user32.GetFunction("GetDpiForSystem");

		_GetDpiForMonitor = _shcore.GetFunction("GetDpiForMonitor");

#include <windows.h>