Common C++ classes and routines used by my applications such as argument parser, IO and conversion utilities
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#include "./nativefilestream.h"
#ifdef CPP_UTILITIES_USE_NATIVE_FILE_BUFFER
#include "./catchiofailure.h"
#ifdef PLATFORM_WINDOWS
#include "../conversion/stringconversion.h"
#endif
// include header files for file buffer implementation
#if defined(CPP_UTILITIES_USE_GNU_CXX_STDIO_FILEBUF)
#include <ext/stdio_filebuf.h>
#elif defined(CPP_UTILITIES_USE_BOOST_IOSTREAMS)
#include <boost/iostreams/device/file_descriptor.hpp>
#include <boost/iostreams/stream.hpp>
#else
#error "Configuration for NativeFileStream backend insufficient."
#endif
// include platform specific header
#if defined(PLATFORM_UNIX)
#include <cstdio>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#elif defined(PLATFORM_WINDOWS)
#include <fcntl.h>
#include <io.h>
#include <sys/stat.h> // yes, this is needed under Windows (https://msdn.microsoft.com/en-US/library/5yhhz3y7.aspx)
#include <windows.h>
#endif
#endif
using namespace std;
namespace IoUtilities {
#ifdef CPP_UTILITIES_USE_NATIVE_FILE_BUFFER
#ifdef CPP_UTILITIES_USE_GNU_CXX_STDIO_FILEBUF
using StreamBuffer = __gnu_cxx::stdio_filebuf<char>;
#else // CPP_UTILITIES_USE_BOOST_IOSTREAMS
using StreamBuffer = boost::iostreams::stream_buffer<boost::iostreams::file_descriptor>;
#endif
struct NativeFileParams {
#ifdef PLATFORM_WINDOWS
NativeFileParams(ios_base::openmode cppOpenMode)
: openMode(cppOpenMode & ios_base::binary ? _O_BINARY : 0)
, flags(cppOpenMode & ios_base::binary ? 0 : _O_TEXT)
, permissions(0)
, access(0)
, shareMode(0)
, creation(0)
{
if ((cppOpenMode & ios_base::out) && (cppOpenMode & ios_base::in)) {
openMode |= _O_RDWR;
access = GENERIC_READ | GENERIC_WRITE;
shareMode = FILE_SHARE_READ;
creation = OPEN_EXISTING;
} else if (cppOpenMode & ios_base::out) {
openMode |= _O_WRONLY | _O_CREAT;
permissions = _S_IREAD | _S_IWRITE;
access = GENERIC_WRITE;
creation = OPEN_ALWAYS;
} else if (cppOpenMode & ios_base::in) {
openMode |= _O_RDONLY;
flags |= _O_RDONLY;
access = GENERIC_READ;
shareMode = FILE_SHARE_READ;
creation = OPEN_EXISTING;
}
if (cppOpenMode & ios_base::app) {
openMode |= _O_APPEND;
flags |= _O_APPEND;
}
if (cppOpenMode & ios_base::trunc) {
openMode |= _O_TRUNC;
creation = (cppOpenMode & ios_base::in) ? TRUNCATE_EXISTING : CREATE_ALWAYS;
}
}
int openMode;
int flags;
int permissions;
DWORD access;
DWORD shareMode;
DWORD creation;
#else
NativeFileParams(ios_base::openmode cppOpenMode)
: openFlags(0)
{
if ((cppOpenMode & ios_base::in) && (cppOpenMode & ios_base::out)) {
if (cppOpenMode & ios_base::app) {
openMode = "a+";
openFlags = O_RDWR | O_APPEND;
} else if (cppOpenMode & ios_base::trunc) {
openMode = "w+";
openFlags = O_RDWR | O_TRUNC;
} else {
openMode = "r+";
openFlags = O_RDWR;
}
} else if (cppOpenMode & ios_base::in) {
openMode = 'r';
openFlags = O_RDONLY;
} else if (cppOpenMode & ios_base::out) {
if (cppOpenMode & ios_base::app) {
openMode = 'a';
openFlags = O_WRONLY | O_APPEND;
} else if (cppOpenMode & ios_base::trunc) {
openMode = 'w';
openFlags = O_WRONLY | O_TRUNC | O_CREAT;
} else {
openMode = "r+";
openFlags = O_WRONLY | O_CREAT;
}
}
if (cppOpenMode & ios_base::binary) {
openMode += 'b';
}
}
std::string openMode;
int openFlags;
#endif
};
/*!
* \brief Constructs a new NativeFileStream which is initially closed.
*/
NativeFileStream::NativeFileStream()
: iostream(new StreamBuffer)
, m_filebuf(rdbuf())
{
}
/*!
* \brief Moves the NativeFileStream.
*/
NativeFileStream::NativeFileStream(NativeFileStream &&other)
: iostream(other.m_filebuf.release())
, m_filebuf(rdbuf())
, m_fileHandle(other.m_fileHandle)
{
}
/*!
* \brief Destroys the NativeFileStream releasing all underlying resources.
*/
NativeFileStream::~NativeFileStream()
{
}
/*!
* \brief Returns whether the file is open.
*/
bool NativeFileStream::is_open() const
{
return m_filebuf && static_cast<const StreamBuffer *>(m_filebuf.get())->is_open();
}
/*!
* \brief Opens the file referenced by \a path with the specified \a openMode.
* \remarks
* Under Windows \a path is expected to be UTF-8 encoded. It is automatically converted so non-ASCII
* characters are treated correctly under Windows (in contrast to std::fstream::open() where only the
* current code page is supported).
*
* Under other platforms the \a path is just passed through so there are no assumptions made about its
* encoding.
* \throws Throws std::ios_base::failure in the error case.
* \todo Maybe use setstate() instead of throwing exceptions directly for consistent error handling
* with std::fstream::open(). However, that makes passing specific error messages difficult.
*/
void NativeFileStream::open(const string &path, ios_base::openmode openMode)
{
setFileBuffer(makeFileBuffer(path, openMode));
}
/*!
* \brief Opens the file from the specified \a fileDescriptor with the specified \a openMode.
* \throws Throws std::ios_base::failure in the error case.
* \todo
* - Maybe use setstate() instead of throwing exceptions directly for consistent error handling
* with std::fstream::open(). However, that makes passing specific error messages difficult.
* - Rename to open() in v5.
*/
void NativeFileStream::openFromFileDescriptor(int fileDescriptor, ios_base::openmode openMode)
{
setFileBuffer(makeFileBuffer(fileDescriptor, openMode));
}
/*!
* \brief Closes the file if opened; otherwise does nothing.
*/
void NativeFileStream::close()
{
if (m_filebuf) {
static_cast<StreamBuffer *>(m_filebuf.get())->close();
}
}
/*!
* \brief Internally called to assign the \a buffer taking. Takes ownership over \a buffer.
*/
void NativeFileStream::setFileBuffer(std::unique_ptr<std::basic_streambuf<char>> buffer)
{
rdbuf(buffer.get());
m_filebuf = std::move(buffer);
}
/*!
* \brief \brief Internally called by open().
*/
std::unique_ptr<std::basic_streambuf<char>> NativeFileStream::makeFileBuffer(const string &path, ios_base::openmode openMode)
{
#ifdef PLATFORM_WINDOWS
// convert path to UTF-16
const auto widePath(makeWidePath(path));
#endif
// compute native params
const NativeFileParams nativeParams(openMode);
#ifdef CPP_UTILITIES_USE_GNU_CXX_STDIO_FILEBUF
// open file handle to initialize stdio_filebuf
#ifdef PLATFORM_WINDOWS
const int fileHandle = _wopen(widePath.get(), nativeParams.openMode, nativeParams.permissions);
if (fileHandle == -1) {
::IoUtilities::throwIoFailure("_wopen failed");
}
#else
const auto fileHandle = fopen(path.data(), nativeParams.openMode.data());
if (!fileHandle) {
::IoUtilities::throwIoFailure("fopen failed");
}
#endif
return make_unique<StreamBuffer>(fileHandle, openMode);
#else // CPP_UTILITIES_USE_BOOST_IOSTREAMS
// create raw file descriptor to initialize boost::iostreams::file_descriptor
#ifdef PLATFORM_WINDOWS
const auto fileDescriptor
= CreateFileW(widePath.get(), nativeParams.access, nativeParams.shareMode, nullptr, nativeParams.creation, FILE_ATTRIBUTE_NORMAL);
if (fileDescriptor == INVALID_HANDLE_VALUE) {
::IoUtilities::throwIoFailure("CreateFileW failed");
}
#else
const auto fileDescriptor = ::open(path.data(), nativeParams.openFlags, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (fileDescriptor == -1) {
::IoUtilities::throwIoFailure("open failed");
}
#endif
return make_unique<StreamBuffer>(fileDescriptor, boost::iostreams::close_handle);
#endif
}
/*!
* \brief Internally called by openFromFileDescriptor().
*/
std::unique_ptr<std::basic_streambuf<char>> NativeFileStream::makeFileBuffer(int fileDescriptor, ios_base::openmode openMode)
{
// compute native params
const NativeFileParams nativeParams(openMode);
#ifdef CPP_UTILITIES_USE_GNU_CXX_STDIO_FILEBUF
// open file handle to initialize stdio_filebuf
#ifdef PLATFORM_WINDOWS
const auto fileHandle = _get_osfhandle(fileDescriptor);
if (fileHandle == -1) {
::IoUtilities::throwIoFailure("_get_osfhandle failed");
}
const auto osFileHandle = _open_osfhandle(fileHandle, nativeParams.flags);
if (osFileHandle == -1) {
::IoUtilities::throwIoFailure("_open_osfhandle failed");
}
#else
const auto fileHandle = fdopen(fileDescriptor, nativeParams.openMode.data());
if (!fileHandle) {
::IoUtilities::throwIoFailure("fdopen failed");
}
#endif
return make_unique<StreamBuffer>(fileDescriptor, openMode);
#else // CPP_UTILITIES_USE_BOOST_IOSTREAMS
// initialize boost::iostreams::file_descriptor from the specified fileDescriptor
return make_unique<StreamBuffer>(fileDescriptor, boost::iostreams::close_handle);
#endif
}
#ifdef PLATFORM_WINDOWS
/*!
* \brief Converts the specified UTF-8 encoded \a path to UTF-16 for passing it to WinAPI functions.
* \throws Throws std::ios_base::failure when an encoding error occurs.
*/
std::unique_ptr<wchar_t[]> NativeFileStream::makeWidePath(const std::string &path)
{
auto widePath = ::ConversionUtilities::convertMultiByteToWide(path);
if (!widePath.first) {
::IoUtilities::throwIoFailure("Unable to convert path to UTF-16");
}
return std::move(widePath.first);
}
#endif
#else
// std::fstream is used
#endif
} // namespace IoUtilities