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// **************************************************************************
// * This file is part of the FreeFileSync project. It is distributed under *
// * GNU General Public License: http://www.gnu.org/licenses/gpl.html *
// * Copyright (C) 2008-2011 ZenJu (zhnmju123 AT gmx.de) *
// **************************************************************************
//
#include "file_io.h"
#include "last_error.h"
#include "i18n.h"
#ifdef FFS_WIN
#include "long_path_prefix.h"
#elif defined FFS_LINUX
#include <cerrno>
#endif
using namespace zen;
FileInput::FileInput(FileHandle handle, const Zstring& filename) :
eofReached(false),
fileHandle(handle),
filename_(filename) {}
FileInput::FileInput(const Zstring& filename) : //throw (FileError, ErrorNotExisting)
eofReached(false),
filename_(filename)
{
#ifdef FFS_WIN
fileHandle = ::CreateFile(zen::applyLongPathPrefix(filename).c_str(),
GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, //all shared modes are required to read open files that are shared by other applications
NULL,
OPEN_EXISTING,
FILE_FLAG_SEQUENTIAL_SCAN,
/* possible values: (Reference http://msdn.microsoft.com/en-us/library/aa363858(VS.85).aspx#caching_behavior)
FILE_FLAG_NO_BUFFERING
FILE_FLAG_RANDOM_ACCESS
FILE_FLAG_SEQUENTIAL_SCAN
tests on Win7 x64 show that FILE_FLAG_SEQUENTIAL_SCAN provides best performance for binary comparison in all cases:
- comparing different physical disks (DVD <-> HDD and HDD <-> HDD)
- even on same physical disk! (HDD <-> HDD)
- independent from client buffer size!
tests on XP show that FILE_FLAG_SEQUENTIAL_SCAN provides best performance for binary comparison when
- comparing different physical disks (DVD <-> HDD)
while FILE_FLAG_RANDOM_ACCESS offers best performance for
- same physical disk (HDD <-> HDD)
Problem: bad XP implementation of prefetch makes flag FILE_FLAG_SEQUENTIAL_SCAN effectively load two files at once from one drive
swapping every 64 kB (or similar). File access times explode!
=> For XP it is critical to use FILE_FLAG_RANDOM_ACCESS (to disable prefetch) if reading two files on same disk and
FILE_FLAG_SEQUENTIAL_SCAN when reading from different disk (e.g. massive performance improvement compared to random access for DVD <-> HDD!)
=> there is no compromise that satisfies all cases! (on XP)
for FFS most comparisons are probably between different disks => let's use FILE_FLAG_SEQUENTIAL_SCAN
*/
NULL);
if (fileHandle == INVALID_HANDLE_VALUE)
{
const DWORD lastError = ::GetLastError();
std::wstring errorMessage = _("Error opening file:") + "\n\"" + filename_ + "\"" + "\n\n" + zen::getLastErrorFormatted(lastError);
if (lastError == ERROR_FILE_NOT_FOUND ||
lastError == ERROR_PATH_NOT_FOUND)
throw ErrorNotExisting(errorMessage);
throw FileError(errorMessage);
}
#elif defined FFS_LINUX
fileHandle = ::fopen(filename.c_str(), "r,type=record,noseek"); //utilize UTF-8 filename
if (fileHandle == NULL)
{
const int lastError = errno;
std::wstring errorMessage = _("Error opening file:") + "\n\"" + filename_ + "\"" + "\n\n" + zen::getLastErrorFormatted(lastError);
if (lastError == ENOENT)
throw ErrorNotExisting(errorMessage);
throw FileError(errorMessage);
}
#endif
}
FileInput::~FileInput()
{
#ifdef FFS_WIN
::CloseHandle(fileHandle);
#elif defined FFS_LINUX
::fclose(fileHandle); //NEVER allow passing NULL to fclose! -> crash!; fileHandle != NULL in this context!
#endif
}
size_t FileInput::read(void* buffer, size_t bytesToRead) //returns actual number of bytes read; throw (FileError)
{
#ifdef FFS_WIN
DWORD bytesRead = 0;
if (!::ReadFile(fileHandle, //__in HANDLE hFile,
buffer, //__out LPVOID lpBuffer,
static_cast<DWORD>(bytesToRead), //__in DWORD nNumberOfBytesToRead,
&bytesRead, //__out_opt LPDWORD lpNumberOfBytesRead,
NULL)) //__inout_opt LPOVERLAPPED lpOverlapped
#elif defined FFS_LINUX
const size_t bytesRead = ::fread(buffer, 1, bytesToRead, fileHandle);
if (::ferror(fileHandle) != 0)
#endif
throw FileError(_("Error reading file:") + "\n\"" + filename_ + "\"" + "\n\n" + zen::getLastErrorFormatted());
#ifdef FFS_WIN
if (bytesRead < bytesToRead) //falsify only!
#elif defined FFS_LINUX
if (::feof(fileHandle) != 0)
#endif
eofReached = true;
if (bytesRead > bytesToRead)
throw FileError(_("Error reading file:") + "\n\"" + filename_ + "\"" + "\n\n" + "buffer overflow");
return bytesRead;
}
bool FileInput::eof() //end of file reached
{
return eofReached;
}
FileOutput::FileOutput(FileHandle handle, const Zstring& filename) : fileHandle(handle), filename_(filename) {}
FileOutput::FileOutput(const Zstring& filename, AccessFlag access) : //throw (FileError, ErrorTargetPathMissing, ErrorTargetExisting)
filename_(filename)
{
#ifdef FFS_WIN
fileHandle = ::CreateFile(zen::applyLongPathPrefix(filename).c_str(),
GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_DELETE, //note: FILE_SHARE_DELETE is required to rename file while handle is open!
NULL,
access == ACC_OVERWRITE ? CREATE_ALWAYS : CREATE_NEW,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,
NULL);
if (fileHandle == INVALID_HANDLE_VALUE)
{
const DWORD lastError = ::GetLastError();
std::wstring errorMessage = _("Error writing file:") + "\n\"" + filename_ + "\"" + "\n\n" + zen::getLastErrorFormatted(lastError);
if (lastError == ERROR_FILE_EXISTS)
throw ErrorTargetExisting(errorMessage);
if (lastError == ERROR_PATH_NOT_FOUND)
throw ErrorTargetPathMissing(errorMessage);
throw FileError(errorMessage);
}
#elif defined FFS_LINUX
fileHandle = ::fopen(filename.c_str(),
//GNU extension: https://www.securecoding.cert.org/confluence/display/cplusplus/FIO03-CPP.+Do+not+make+assumptions+about+fopen()+and+file+creation
access == ACC_OVERWRITE ? "w,type=record,noseek" : "wx,type=record,noseek");
if (fileHandle == NULL)
{
const int lastError = errno;
std::wstring errorMessage = _("Error writing file:") + "\n\"" + filename_ + "\"" + "\n\n" + zen::getLastErrorFormatted(lastError);
if (lastError == EEXIST)
throw ErrorTargetExisting(errorMessage);
if (lastError == ENOENT)
throw ErrorTargetPathMissing(errorMessage);
throw FileError(errorMessage);
}
#endif
}
FileOutput::~FileOutput()
{
#ifdef FFS_WIN
::CloseHandle(fileHandle);
#elif defined FFS_LINUX
::fclose(fileHandle); //NEVER allow passing NULL to fclose! -> crash!
#endif
}
void FileOutput::write(const void* buffer, size_t bytesToWrite) //throw (FileError)
{
#ifdef FFS_WIN
DWORD bytesWritten = 0;
if (!::WriteFile(fileHandle, //__in HANDLE hFile,
buffer, //__out LPVOID lpBuffer,
static_cast<DWORD>(bytesToWrite), //__in DWORD nNumberOfBytesToWrite,
&bytesWritten, //__out_opt LPDWORD lpNumberOfBytesWritten,
NULL)) //__inout_opt LPOVERLAPPED lpOverlapped
#elif defined FFS_LINUX
const size_t bytesWritten = ::fwrite(buffer, 1, bytesToWrite, fileHandle);
if (::ferror(fileHandle) != 0)
#endif
throw FileError(_("Error writing file:") + "\n\"" + filename_ + "\"" + "\n\n" + zen::getLastErrorFormatted() + " (w)"); //w -> distinguish from fopen error message!
if (bytesWritten != bytesToWrite) //must be fulfilled for synchronous writes!
throw FileError(_("Error writing file:") + "\n\"" + filename_ + "\"" + "\n\n" + "incomplete write");
}
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