code_device/twain/sane_helper.cpp

#include "sane_helper.h"
#include "huagao/brand.h"
#include "utils.h"


#include <string.h>



//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// win util

#if OS_WIN

#define LoadLibraryExA	win_util::load_dll

namespace win_util
{
	std::string get_registry_string(HKEY root, const char* path, const char* name)
	{
		HKEY	key = NULL;

		RegOpenKeyA(root, path, &key);
		if (!key)
			return "";

		char* buf = NULL;
		DWORD	len = 0;
		DWORD	type = REG_SZ;
		std::string ret("");

		RegQueryValueExA(key, name, NULL, &type, (LPBYTE)buf, &len);
		if (len)
		{
			buf = new char[len + 4];
			memset(buf, 0, (len + 4) * sizeof(*buf));
			RegQueryValueExA(key, name, NULL, &type, (LPBYTE)buf, &len);
			ret = buf;
			delete[] buf;
		}
		RegCloseKey(key);

		return ret;
	}
	HMODULE load_dll(const char* path_dll, int flag, int* err)
	{
		HMODULE h = LoadLibraryA(path_dll);
		int		ret = GetLastError();
		
		utils::to_log(1, "[TWAIN]Load: LoadLibraryA(%s) = %d\r\n", path_dll, ret);
		if (!h && (ret == ERROR_MOD_NOT_FOUND || ret == ERROR_BAD_EXE_FORMAT))
		{
			std::string	dir(path_dll);
			size_t		pos = dir.rfind('\\');
			char		path[MAX_PATH] = { 0 };

			GetDllDirectoryA(_countof(path) - 1, path);
			if (pos != std::wstring::npos)
				dir.erase(pos);
			utils::to_log(LOG_LEVEL_FATAL, "[TWAIN]Load: change directory to '%s' and retry LoadLibraryA(%s) ...\r\n", dir.c_str(), path_dll);
			SetDllDirectoryA(dir.c_str());
			h = LoadLibraryA(path_dll);
			// h = LoadLibraryExW(path_dll, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
			ret = GetLastError();
			utils::to_log(1, "[TWAIN]Load: trying LoadLibraryA(%s) = %d, restore directory to '%s'\r\n", path_dll, ret, path);
			SetDllDirectoryA(path);
		}

		if (err)
			*err = ret;

		return h;
	}
};
#else
#include <dlfcn.h>
#endif


//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// sane_helper
sane_helper::sane_helper()
{
	// find sane root directory ...
#if OS_WIN
	std::string	path(win_util::get_registry_string(HKEY_LOCAL_MACHINE, (std::string("Software\\") + PRODUCT_VENDOR + "Scan").c_str(), sizeof(void*) == 4 ? "DriverPath" : "DriverPath64"));
	dll_root_ = path + PATH_SEPARATOR;
#else
	std::string path(utils::get_module_full_path("libc"));
	size_t		pos = path.rfind(PATH_SEPARATOR[0]);

	if(pos++ != std::string::npos)
	{
		path.erase(pos);
		dll_root_ = std::move(path);
		dll_root_ += "sane/";
	}
#endif

	utils::to_log(1, "sane path is: %s\n", dll_root_.c_str());
}
sane_helper::~sane_helper()
{
	clear();
}

void sane_helper::clear(void)
{
	invoke_sane_init = nullptr;
	invoke_sane_exit = nullptr;
	invoke_sane_get_devices = nullptr;
	invoke_sane_open = nullptr;
	invoke_sane_close = nullptr;
	invoke_sane_get_option_descriptor = nullptr;
	invoke_sane_control_option = nullptr;
	invoke_sane_get_parameters = nullptr;
	invoke_sane_start = nullptr;
	invoke_sane_read = nullptr;
	invoke_sane_cancel = nullptr;
	invoke_sane_set_io_mode = nullptr;
	invoke_sane_get_select_fd = nullptr;
	invoke_sane_strstatus = nullptr;

	if(dll_handle_)
	{
		FreeLibrary(dll_handle_);
		dll_handle_ = nullptr;
	}
}

bool sane_helper::load_sane(const char* vendor)	// libsane_hgsane.so.1, and vendor is 'hgsane'
{
#if OS_WIN
	std::string	file(dll_root_ + "sane.dll"), func("sane_");
#else
	std::string	file(dll_root_ + "libsane-" + vendor + ".so.1"), func("sane_");
#endif
	bool		ok = true;

	clear();
	dll_handle_ = LoadLibraryExA(file.c_str(), 0, RTLD_NOW);
	if(!dll_handle_)
	{
		utils::to_log(7, "load sane library(%s) = %s\n", file.c_str(), strerror(errno));
		return false;
	}

	func += vendor;
	func += "_";

	#define GET_PROC_ADDR(api)	\
		*(void**)&invoke_sane_##api = GetProcAddress(dll_handle_, (func + #api).c_str());	\
		ok &= invoke_sane_##api != nullptr;

	GET_PROC_ADDR(init);
	GET_PROC_ADDR(init_ex);
	GET_PROC_ADDR(exit);
	GET_PROC_ADDR(get_devices);
	GET_PROC_ADDR(open);
	GET_PROC_ADDR(close);
	GET_PROC_ADDR(get_option_descriptor);
	GET_PROC_ADDR(control_option);
	GET_PROC_ADDR(get_parameters);
	GET_PROC_ADDR(start);
	GET_PROC_ADDR(read);
	GET_PROC_ADDR(cancel);
	GET_PROC_ADDR(set_io_mode);
	GET_PROC_ADDR(get_select_fd);
	GET_PROC_ADDR(strstatus);
	if(!ok)
		clear();

	return ok;
}