love/src/modules/filesystem/wrap_File.cpp

/**
 * Copyright (c) 2006-2021 LOVE Development Team
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 **/

#include "wrap_File.h"

#include "common/Data.h"
#include "common/Exception.h"
#include "common/int.h"

#include "data/wrap_DataModule.h"

namespace love
{
namespace filesystem
{

int luax_ioError(lua_State *L, const char *fmt, ...)
{
	va_list args;
	va_start(args, fmt);

	lua_pushnil(L);
	lua_pushvfstring(L, fmt, args);

	va_end(args);
	return 2;
}

File *luax_checkfile(lua_State *L, int idx)
{
	return luax_checktype<File>(L, idx);
}

int w_File_getSize(lua_State *L)
{
	File *t = luax_checkfile(L, 1);

	int64 size = -1;
	try
	{
		size = t->getSize();
	}
	catch (love::Exception &e)
	{
		return luax_ioError(L, "%s", e.what());
	}

	// Push nil on failure or if size does not fit into a double precision floating-point number.
	if (size == -1)
		return luax_ioError(L, "Could not determine file size.");
	else if (size >= 0x20000000000000LL)
		return luax_ioError(L, "Size is too large.");

	lua_pushnumber(L, (lua_Number) size);
	return 1;
}

int w_File_open(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	const char *str = luaL_checkstring(L, 2);
	File::Mode mode;

	if (!File::getConstant(str, mode))
		return luax_enumerror(L, "file open mode", File::getConstants(mode), str);

	try
	{
		luax_pushboolean(L, file->open(mode));
	}
	catch (love::Exception &e)
	{
		return luax_ioError(L, "%s", e.what());
	}

	return 1;
}

int w_File_close(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	luax_pushboolean(L, file->close());
	return 1;
}

int w_File_isOpen(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	luax_pushboolean(L, file->isOpen());
	return 1;
}

int w_File_read(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	StrongRef<FileData> d = nullptr;

	love::data::ContainerType ctype = love::data::CONTAINER_STRING;

	int startidx = 2;
	if (lua_type(L, 2) == LUA_TSTRING)
	{
		ctype = love::data::luax_checkcontainertype(L, 2);
		startidx = 3;
	}

	int64 size = (int64) luaL_optnumber(L, startidx, (lua_Number) File::ALL);

	try
	{
		d.set(file->read(size), Acquire::NORETAIN);
	}
	catch (love::Exception &e)
	{
		return luax_ioError(L, "%s", e.what());
	}

	if (ctype == love::data::CONTAINER_DATA)
		luax_pushtype(L, d.get());
	else
		lua_pushlstring(L, (const char *) d->getData(), d->getSize());

	lua_pushinteger(L, d->getSize());

	return 2;
}

int w_File_write(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	bool result = false;

	if (lua_isstring(L, 2))
	{
		try
		{
			size_t datasize = 0;
			const char *data = lua_tolstring(L, 2, &datasize);

			if (!lua_isnoneornil(L, 3))
				datasize = luaL_checkinteger(L, 3);

			result = file->write(data, datasize);
		}
		catch (love::Exception &e)
		{
			return luax_ioError(L, "%s", e.what());
		}
	}
	else if (luax_istype(L, 2, love::Data::type))
	{
		try
		{
			love::Data *data = luax_totype<love::Data>(L, 2);
			result = file->write(data, luaL_optinteger(L, 3, data->getSize()));
		}
		catch (love::Exception &e)
		{
			return luax_ioError(L, "%s", e.what());
		}
	}
	else
	{
		return luaL_argerror(L, 2, "string or data expected");
	}

	luax_pushboolean(L, result);
	return 1;
}

int w_File_flush(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	bool success = false;
	try
	{
		success = file->flush();
	}
	catch (love::Exception &e)
	{
		return luax_ioError(L, "%s", e.what());
	}
	luax_pushboolean(L, success);
	return 1;
}

int w_File_isEOF(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	luax_pushboolean(L, file->isEOF());
	return 1;
}

int w_File_tell(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	int64 pos = file->tell();
	// Push nil on failure or if pos does not fit into a double precision floating-point number.
	if (pos == -1)
		return luax_ioError(L, "Invalid position.");
	else if (pos >= 0x20000000000000LL)
		return luax_ioError(L, "Number is too large.");
	else
		lua_pushnumber(L, (lua_Number)pos);
	return 1;
}

int w_File_seek(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	lua_Number pos = luaL_checknumber(L, 2);

	// Push false on negative and precision-problematic numbers.
	// Better fail than seek to an unknown position.
	if (pos < 0.0 || pos >= 9007199254740992.0)
		luax_pushboolean(L, false);
	else
		luax_pushboolean(L, file->seek((uint64)pos));
	return 1;
}

int w_File_lines_i(lua_State *L)
{
	// The upvalues:
	//   - File
	//   - read buffer (string)
	//   - read buffer offset (number)
	//   - file position (number, optional)
	//   - restore userpos (bool, optional)

	File *file = luax_checktype<File>(L, lua_upvalueindex(1));

	// Only accept read mode at this point.
	if (file->getMode() != File::MODE_READ)
		return luaL_error(L, "File needs to stay in read mode.");

	// Get the current (lua-side) buffer info
	size_t len;
	const char *buffer = lua_tolstring(L, lua_upvalueindex(2), &len);
	int offset = lua_tointeger(L, lua_upvalueindex(3));

	// Find our next line
	const char *start = buffer+offset;
	const char *end = reinterpret_cast<const char*>(memchr(start, '\n', len-offset));

	bool seekBack = luax_toboolean(L, lua_upvalueindex(5));

	// If there are no more lines in the buffer, keep adding more data until we
	// found another line or EOF
	if (!end && !file->isEOF())
	{
		const int readbufsize = 1024;
		char readbuf[readbufsize];

		// Build new buffer
		luaL_Buffer storage;
		luaL_buffinit(L, &storage);
		luaL_addlstring(&storage, start, len-offset);

		// If the user has changed the position, we need to seek back first
		int64 pos = file->tell();
		int64 userpos = -1;
		if (seekBack)
		{
			userpos = pos;
			pos = (int64) lua_tonumber(L, lua_upvalueindex(4));
			if (userpos != pos)
				file->seek(pos);
		}

		// Keep reading until newline or EOF
		while (!file->isEOF())
		{
			int read = (int) file->read(readbuf, readbufsize);
			if (read < 0)
				return luaL_error(L, "Could not read from file.");

			luaL_addlstring(&storage, readbuf, read);

			// If we found a newline now, break
			if (memchr(readbuf, '\n', read))
				break;
		}

		// Possibly seek back to the user position
		// But make sure to save our target position too
		if (seekBack)
		{
			lua_pushnumber(L, file->tell());
			lua_replace(L, lua_upvalueindex(4));
			file->seek(userpos);
		}

		// We've now got a new buffer, replace the old one
		luaL_pushresult(&storage);
		lua_replace(L, lua_upvalueindex(2));
		buffer = lua_tolstring(L, lua_upvalueindex(2), &len);
		offset = 0;
		start = buffer;
		end = reinterpret_cast<const char*>(memchr(start, '\n', len));
	}

	if (!end)
		end = buffer+len-1;

	// We've found the next line, update our offset upvalue and return
	offset = end-buffer+1;
	lua_pushinteger(L, offset);
	lua_replace(L, lua_upvalueindex(3));

	// If we're past the end, terminate (as we must be at EOF)
	if (start == buffer+len)
	{
		file->close();
		return 0;
	}

	// Unless we're at EOF, end points at '\n', so let's take that (and an
	// optional '\r') off
	if (end >= start && *end == '\n')
		--end;
	if (end >= start && *end == '\r')
		--end;

	// Note: inclusive because *end contains the last character in the string
	lua_pushlstring(L, start, end-start+1);
	return 1;
}

int w_File_lines(lua_State *L)
{
	File *file = luax_checkfile(L, 1);

	lua_pushstring(L, ""); // buffer
	lua_pushnumber(L, 0); // buffer offset
	lua_pushnumber(L, 0); // File position.
	luax_pushboolean(L, file->getMode() != File::MODE_CLOSED); // Save current file position.

	if (file->getMode() != File::MODE_READ)
	{
		if (file->getMode() != File::MODE_CLOSED)
			file->close();

		bool success = false;
		luax_catchexcept(L, [&](){ success = file->open(File::MODE_READ); });

		if (!success)
			return luaL_error(L, "Could not open file.");
	}

	lua_pushcclosure(L, w_File_lines_i, 5);
	return 1;
}

int w_File_setBuffer(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	const char *str = luaL_checkstring(L, 2);
	int64 size = (int64) luaL_optnumber(L, 3, 0.0);

	File::BufferMode bufmode;
	if (!File::getConstant(str, bufmode))
		return luax_enumerror(L, "file buffer mode", File::getConstants(bufmode), str);

	bool success = false;
	try
	{
		success = file->setBuffer(bufmode, size);
	}
	catch (love::Exception &e)
	{
		return luax_ioError(L, "%s", e.what());
	}

	luax_pushboolean(L, success);
	return 1;
}

int w_File_getBuffer(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	int64 size = 0;
	File::BufferMode bufmode = file->getBuffer(size);
	const char *str = 0;

	if (!File::getConstant(bufmode, str))
		return luax_ioError(L, "Unknown file buffer mode.");

	lua_pushstring(L, str);
	lua_pushnumber(L, (lua_Number) size);
	return 2;
}

int w_File_getMode(lua_State *L)
{
	File *file = luax_checkfile(L, 1);

	File::Mode mode = file->getMode();
	const char *str = 0;

	if (!File::getConstant(mode, str))
		return luax_ioError(L, "Unknown file mode.");

	lua_pushstring(L, str);
	return 1;
}

int w_File_getFilename(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	luax_pushstring(L, file->getFilename());
	return 1;
}

int w_File_getExtension(lua_State *L)
{
	File *file = luax_checkfile(L, 1);
	luax_pushstring(L, file->getExtension());
	return 1;
}

const luaL_Reg w_File_functions[] =
{
	{ "getSize", w_File_getSize },
	{ "open", w_File_open },
	{ "close", w_File_close },
	{ "isOpen", w_File_isOpen },
	{ "read", w_File_read },
	{ "write", w_File_write },
	{ "flush", w_File_flush },
	{ "isEOF", w_File_isEOF },
	{ "tell", w_File_tell },
	{ "seek", w_File_seek },
	{ "lines", w_File_lines },
	{ "setBuffer", w_File_setBuffer },
	{ "getBuffer", w_File_getBuffer },
	{ "getMode", w_File_getMode },
	{ "getFilename", w_File_getFilename },
	{ "getExtension", w_File_getExtension },
	{ 0, 0 }
};

extern "C" int luaopen_file(lua_State *L)
{
	return luax_register_type(L, &File::type, w_File_functions, nullptr);
}

} // filesystem
} // love