boost/beast/core/impl/file_win32.ipp
//
// Copyright (c) 2015-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/beast
//
#ifndef BOOST_BEAST_CORE_IMPL_FILE_WIN32_IPP
#define BOOST_BEAST_CORE_IMPL_FILE_WIN32_IPP
#include <boost/beast/core/file_win32.hpp>
#if BOOST_BEAST_USE_WIN32_FILE
#include <boost/beast/core/detail/win32_unicode_path.hpp>
#include <boost/core/exchange.hpp>
#include <boost/winapi/access_rights.hpp>
#include <boost/winapi/error_codes.hpp>
#include <boost/winapi/get_last_error.hpp>
#include <limits>
#include <utility>
namespace boost {
namespace beast {
namespace detail {
// VFALCO Can't seem to get boost/detail/winapi to work with
// this so use the non-Ex version for now.
BOOST_BEAST_DECL
boost::winapi::BOOL_
set_file_pointer_ex(
boost::winapi::HANDLE_ hFile,
boost::winapi::LARGE_INTEGER_ lpDistanceToMove,
boost::winapi::PLARGE_INTEGER_ lpNewFilePointer,
boost::winapi::DWORD_ dwMoveMethod)
{
auto dwHighPart = lpDistanceToMove.u.HighPart;
auto dwLowPart = boost::winapi::SetFilePointer(
hFile,
lpDistanceToMove.u.LowPart,
&dwHighPart,
dwMoveMethod);
if(dwLowPart == boost::winapi::INVALID_SET_FILE_POINTER_)
return 0;
if(lpNewFilePointer)
{
lpNewFilePointer->u.LowPart = dwLowPart;
lpNewFilePointer->u.HighPart = dwHighPart;
}
return 1;
}
} // detail
file_win32::
~file_win32()
{
if(h_ != boost::winapi::INVALID_HANDLE_VALUE_)
boost::winapi::CloseHandle(h_);
}
file_win32::
file_win32(file_win32&& other)
: h_(boost::exchange(other.h_,
boost::winapi::INVALID_HANDLE_VALUE_))
{
}
file_win32&
file_win32::
operator=(file_win32&& other)
{
if(&other == this)
return *this;
if(h_)
boost::winapi::CloseHandle(h_);
h_ = other.h_;
other.h_ = boost::winapi::INVALID_HANDLE_VALUE_;
return *this;
}
void
file_win32::
native_handle(native_handle_type h)
{
if(h_ != boost::winapi::INVALID_HANDLE_VALUE_)
boost::winapi::CloseHandle(h_);
h_ = h;
}
void
file_win32::
close(error_code& ec)
{
if(h_ != boost::winapi::INVALID_HANDLE_VALUE_)
{
if(! boost::winapi::CloseHandle(h_))
ec.assign(boost::winapi::GetLastError(),
system_category());
else
ec = {};
h_ = boost::winapi::INVALID_HANDLE_VALUE_;
}
else
{
ec = {};
}
}
void
file_win32::
open(char const* path, file_mode mode, error_code& ec)
{
if(h_ != boost::winapi::INVALID_HANDLE_VALUE_)
{
boost::winapi::CloseHandle(h_);
h_ = boost::winapi::INVALID_HANDLE_VALUE_;
}
boost::winapi::DWORD_ share_mode = 0;
boost::winapi::DWORD_ desired_access = 0;
boost::winapi::DWORD_ creation_disposition = 0;
boost::winapi::DWORD_ flags_and_attributes = 0;
/*
| When the file...
This argument: | Exists Does not exist
-------------------------+------------------------------------------------------
CREATE_ALWAYS | Truncates Creates
CREATE_NEW +-----------+ Fails Creates
OPEN_ALWAYS ===| does this |===> Opens Creates
OPEN_EXISTING +-----------+ Opens Fails
TRUNCATE_EXISTING | Truncates Fails
*/
switch(mode)
{
default:
case file_mode::read:
desired_access = boost::winapi::GENERIC_READ_;
share_mode = boost::winapi::FILE_SHARE_READ_;
creation_disposition = boost::winapi::OPEN_EXISTING_;
flags_and_attributes = 0x10000000; // FILE_FLAG_RANDOM_ACCESS
break;
case file_mode::scan:
desired_access = boost::winapi::GENERIC_READ_;
share_mode = boost::winapi::FILE_SHARE_READ_;
creation_disposition = boost::winapi::OPEN_EXISTING_;
flags_and_attributes = 0x08000000; // FILE_FLAG_SEQUENTIAL_SCAN
break;
case file_mode::write:
desired_access = boost::winapi::GENERIC_READ_ |
boost::winapi::GENERIC_WRITE_;
creation_disposition = boost::winapi::CREATE_ALWAYS_;
flags_and_attributes = 0x10000000; // FILE_FLAG_RANDOM_ACCESS
break;
case file_mode::write_new:
desired_access = boost::winapi::GENERIC_READ_ |
boost::winapi::GENERIC_WRITE_;
creation_disposition = boost::winapi::CREATE_NEW_;
flags_and_attributes = 0x10000000; // FILE_FLAG_RANDOM_ACCESS
break;
case file_mode::write_existing:
desired_access = boost::winapi::GENERIC_READ_ |
boost::winapi::GENERIC_WRITE_;
creation_disposition = boost::winapi::OPEN_EXISTING_;
flags_and_attributes = 0x10000000; // FILE_FLAG_RANDOM_ACCESS
break;
case file_mode::append:
desired_access = boost::winapi::GENERIC_READ_ |
boost::winapi::GENERIC_WRITE_;
creation_disposition = boost::winapi::OPEN_ALWAYS_;
flags_and_attributes = 0x08000000; // FILE_FLAG_SEQUENTIAL_SCAN
break;
case file_mode::append_existing:
desired_access = boost::winapi::GENERIC_READ_ |
boost::winapi::GENERIC_WRITE_;
creation_disposition = boost::winapi::OPEN_EXISTING_;
flags_and_attributes = 0x08000000; // FILE_FLAG_SEQUENTIAL_SCAN
break;
}
detail::win32_unicode_path unicode_path(path, ec);
if (ec)
return;
h_ = ::CreateFileW(
unicode_path.c_str(),
desired_access,
share_mode,
NULL,
creation_disposition,
flags_and_attributes,
NULL);
if (h_ == boost::winapi::INVALID_HANDLE_VALUE_)
{
ec.assign(boost::winapi::GetLastError(),
system_category());
return;
}
if (mode == file_mode::append ||
mode == file_mode::append_existing)
{
boost::winapi::LARGE_INTEGER_ in;
in.QuadPart = 0;
if (!detail::set_file_pointer_ex(h_, in, 0,
boost::winapi::FILE_END_))
{
ec.assign(boost::winapi::GetLastError(),
system_category());
boost::winapi::CloseHandle(h_);
h_ = boost::winapi::INVALID_HANDLE_VALUE_;
return;
}
}
ec = {};
}
std::uint64_t
file_win32::
size(error_code& ec) const
{
if(h_ == boost::winapi::INVALID_HANDLE_VALUE_)
{
ec = make_error_code(errc::bad_file_descriptor);
return 0;
}
boost::winapi::LARGE_INTEGER_ fileSize;
if(! boost::winapi::GetFileSizeEx(h_, &fileSize))
{
ec.assign(boost::winapi::GetLastError(),
system_category());
return 0;
}
ec = {};
return fileSize.QuadPart;
}
std::uint64_t
file_win32::
pos(error_code& ec)
{
if(h_ == boost::winapi::INVALID_HANDLE_VALUE_)
{
ec = make_error_code(errc::bad_file_descriptor);
return 0;
}
boost::winapi::LARGE_INTEGER_ in;
boost::winapi::LARGE_INTEGER_ out;
in.QuadPart = 0;
if(! detail::set_file_pointer_ex(h_, in, &out,
boost::winapi::FILE_CURRENT_))
{
ec.assign(boost::winapi::GetLastError(),
system_category());
return 0;
}
ec = {};
return out.QuadPart;
}
void
file_win32::
seek(std::uint64_t offset, error_code& ec)
{
if(h_ == boost::winapi::INVALID_HANDLE_VALUE_)
{
ec = make_error_code(errc::bad_file_descriptor);
return;
}
boost::winapi::LARGE_INTEGER_ in;
in.QuadPart = offset;
if(! detail::set_file_pointer_ex(h_, in, 0,
boost::winapi::FILE_BEGIN_))
{
ec.assign(boost::winapi::GetLastError(),
system_category());
return;
}
ec = {};
}
std::size_t
file_win32::
read(void* buffer, std::size_t n, error_code& ec)
{
if(h_ == boost::winapi::INVALID_HANDLE_VALUE_)
{
ec = make_error_code(errc::bad_file_descriptor);
return 0;
}
std::size_t nread = 0;
while(n > 0)
{
boost::winapi::DWORD_ amount;
if(n > (std::numeric_limits<
boost::winapi::DWORD_>::max)())
amount = (std::numeric_limits<
boost::winapi::DWORD_>::max)();
else
amount = static_cast<
boost::winapi::DWORD_>(n);
boost::winapi::DWORD_ bytesRead;
if(! ::ReadFile(h_, buffer, amount, &bytesRead, 0))
{
auto const dwError = boost::winapi::GetLastError();
if(dwError != boost::winapi::ERROR_HANDLE_EOF_)
ec.assign(dwError, system_category());
else
ec = {};
return nread;
}
if(bytesRead == 0)
return nread;
n -= bytesRead;
nread += bytesRead;
buffer = static_cast<char*>(buffer) + bytesRead;
}
ec = {};
return nread;
}
std::size_t
file_win32::
write(void const* buffer, std::size_t n, error_code& ec)
{
if(h_ == boost::winapi::INVALID_HANDLE_VALUE_)
{
ec = make_error_code(errc::bad_file_descriptor);
return 0;
}
std::size_t nwritten = 0;
while(n > 0)
{
boost::winapi::DWORD_ amount;
if(n > (std::numeric_limits<
boost::winapi::DWORD_>::max)())
amount = (std::numeric_limits<
boost::winapi::DWORD_>::max)();
else
amount = static_cast<
boost::winapi::DWORD_>(n);
boost::winapi::DWORD_ bytesWritten;
if(! ::WriteFile(h_, buffer, amount, &bytesWritten, 0))
{
auto const dwError = boost::winapi::GetLastError();
if(dwError != boost::winapi::ERROR_HANDLE_EOF_)
ec.assign(dwError, system_category());
else
ec = {};
return nwritten;
}
if(bytesWritten == 0)
return nwritten;
n -= bytesWritten;
nwritten += bytesWritten;
buffer = static_cast<char const*>(buffer) + bytesWritten;
}
ec = {};
return nwritten;
}
} // beast
} // boost
#endif
#endif