scummvm/backends/fs/stdiostream.cpp

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#if !defined(DISABLE_STDIO_FILESTREAM)

// Disable symbol overrides so that we can use FILE, fopen etc.
#define FORBIDDEN_SYMBOL_ALLOW_ALL

// for Windows unicode fopen(): _wfopen() and for Win32::moveFile()
#if defined(WIN32)
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include "backends/platform/sdl/win32/win32_wrapper.h"
#endif

// Include this after windows.h so we don't get a warning for redefining ARRAYSIZE
#include "backends/fs/stdiostream.h"
#include "common/textconsole.h"

#if defined(__DC__)
// libronin doesn't support rename
#define STDIOSTREAM_NO_ATOMIC_SUPPORT
#endif
#if defined(ATARI)
// Atari file names must have a 8.3 format, atomic breaks this
#define STDIOSTREAM_NO_ATOMIC_SUPPORT
#endif
#if defined(RISCOS)
// RISC OS file names are expected to be 10 characters or less, atomic makes this hard to guarantee
#define STDIOSTREAM_NO_ATOMIC_SUPPORT
#endif

StdioStream::StdioStream(void *handle) : _handle(handle), _path(nullptr) {
	assert(handle);
}

StdioStream::~StdioStream() {
	fclose((FILE *)_handle);

	if (!_path) {
		return;
	}

	// _path is set: recreate the temporary file name and rename the file to
	// its real name
	Common::String tmpPath(*_path);
	tmpPath += ".tmp";

	if (!moveFile(tmpPath, *_path)) {
		warning("Couldn't save file %s", _path->c_str());
	}

	delete _path;
}

bool StdioStream::moveFile(const Common::String &src, const Common::String &dst) {
#ifndef STDIOSTREAM_NO_ATOMIC_SUPPORT
	// This piece of code can't be in a subclass override, as moveFile is called from the destructor.
	// In this case, the vtable is reset to the StdioStream one before calling moveFile.
#if defined(WIN32)
	return Win32::moveFile(src, dst);
#else
	if (!rename(src.c_str(), dst.c_str())) {
		return true;
	}

	// Error: try to delete the file first
	(void)remove(dst.c_str());
	return !rename(src.c_str(), dst.c_str());
#endif
#else // STDIOSTREAM_NO_ATOMIC_SUPPORT
	return false;
#endif
}

bool StdioStream::err() const {
	return ferror((FILE *)_handle) != 0;
}

void StdioStream::clearErr() {
	clearerr((FILE *)_handle);
}

bool StdioStream::eos() const {
	return feof((FILE *)_handle) != 0;
}

int64 StdioStream::pos() const {
#if defined(WIN32)
	return _ftelli64((FILE *)_handle);
#elif defined(HAS_FSEEKO_OFFT_64)
	return ftello((FILE *)_handle);
#elif defined(HAS_FSEEKO64)
	return ftello64((FILE *)_handle);
#else
	return ftell((FILE *)_handle);
#endif
}

int64 StdioStream::size() const {
#if defined(WIN32)
	int64 oldPos = _ftelli64((FILE *)_handle);
	_fseeki64((FILE *)_handle, 0, SEEK_END);
	int64 length = _ftelli64((FILE *)_handle);
	_fseeki64((FILE *)_handle, oldPos, SEEK_SET);
#elif defined(HAS_FSEEKO_OFFT_64)
	int64 oldPos = ftello((FILE *)_handle);
	fseeko((FILE *)_handle, 0, SEEK_END);
	int64 length = ftello((FILE *)_handle);
	fseeko((FILE *)_handle, oldPos, SEEK_SET);
#elif defined(HAS_FSEEKO64)
	int64 oldPos = ftello64((FILE *)_handle);
	fseeko64((FILE *)_handle, 0, SEEK_END);
	int64 length = ftello64((FILE *)_handle);
	fseeko64((FILE *)_handle, oldPos, SEEK_SET);
#else
	int64 oldPos = ftell((FILE *)_handle);
	fseek((FILE *)_handle, 0, SEEK_END);
	int64 length = ftell((FILE *)_handle);
	fseek((FILE *)_handle, oldPos, SEEK_SET);
#endif

	return length;
}

bool StdioStream::seek(int64 offs, int whence) {
#if defined(WIN32)
	return _fseeki64((FILE *)_handle, offs, whence) == 0;
#elif defined(HAS_FSEEKO_OFFT_64)
	return fseeko((FILE *)_handle, offs, whence) == 0;
#elif defined(HAS_FSEEKO64)
	return fseeko64((FILE *)_handle, offs, whence) == 0;
#else
	return fseek((FILE *)_handle, offs, whence) == 0;
#endif
}

uint32 StdioStream::read(void *ptr, uint32 len) {
	return fread((byte *)ptr, 1, len, (FILE *)_handle);
}

bool StdioStream::setBufferSize(uint32 bufferSize) {
	if (bufferSize != 0) {
		return setvbuf((FILE *)_handle, nullptr, _IOFBF, bufferSize) == 0;
	} else {
		return setvbuf((FILE *)_handle, nullptr, _IONBF, 0) == 0;
	}
}

uint32 StdioStream::write(const void *ptr, uint32 len) {
	return fwrite(ptr, 1, len, (FILE *)_handle);
}

bool StdioStream::flush() {
	return fflush((FILE *)_handle) == 0;
}

StdioStream *StdioStream::makeFromPathHelper(const Common::String &path, WriteMode writeMode,
		StdioStream *(*factory)(void *handle)) {
	Common::String tmpPath(path);

	// If no atmoic support is compiled in, WriteMode_WriteAtomic must behave like WriteMode_Write
#ifndef STDIOSTREAM_NO_ATOMIC_SUPPORT
	// In atomic mode we create a temporary file and rename it when closing the file descriptor
	if (writeMode == WriteMode_WriteAtomic) {
		tmpPath += ".tmp";
	}
#endif

#if defined(WIN32) && defined(UNICODE)
	wchar_t *wPath = Win32::stringToTchar(tmpPath);
	FILE *handle = _wfopen(wPath, writeMode == WriteMode_Read ? L"rb" : L"wb");
	free(wPath);
#elif defined(HAS_FOPEN64)
	FILE *handle = fopen64(tmpPath.c_str(), writeMode == WriteMode_Read ? "rb" : "wb");
#else
	FILE *handle = fopen(tmpPath.c_str(), writeMode == WriteMode_Read ? "rb" : "wb");
#endif

	if (!handle) {
		return nullptr;
	}

	StdioStream *stream = factory(handle);

#ifndef STDIOSTREAM_NO_ATOMIC_SUPPORT
	// Store the final path alongside the stream
	// If _path is not nullptr, it will be used to rename the file
	// when closing it
	if (writeMode == WriteMode_WriteAtomic) {
		stream->_path = new Common::String(path);
	}
#endif

	return stream;
}

#endif