libcruft-util/io_win32.cpp

238 lines
5.5 KiB
C++

/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2014 Danny Robson <danny@nerdcruft.net>
*/
#include "io_win32.hpp"
#include "debug.hpp"
#include "win32/except.hpp"
#include "win32/windows.hpp"
#include <winbase.h>
using cruft::detail::win32::mapped_file;
///////////////////////////////////////////////////////////////////////////////
static constexpr
DWORD
fflags_to_generic (int flags) {
switch (flags) {
case O_RDONLY: return GENERIC_READ;
case O_WRONLY: return GENERIC_WRITE;
case O_RDWR: return GENERIC_READ | GENERIC_WRITE;
}
unreachable ();
}
//-----------------------------------------------------------------------------
static constexpr
DWORD
fflags_to_access (int fflags)
{
switch (fflags) {
case O_RDONLY: return FILE_MAP_READ;
case O_WRONLY: return FILE_MAP_WRITE;
case O_RDWR: return FILE_MAP_WRITE;
}
unreachable ();
}
//-----------------------------------------------------------------------------
static constexpr
DWORD
mflags_to_protect (int mflags) {
DWORD res = 0;
if (mflags & PROT_READ) res |= PAGE_READONLY;
if (mflags & PROT_WRITE) res |= PAGE_READWRITE;
if (mflags & PROT_EXEC) res |= PAGE_EXECUTE;
return res;
}
///////////////////////////////////////////////////////////////////////////////
mapped_file::mapped_file (::cruft::win32::file &&src,
int fflags,
int mflags):
m_file (std::forward<::cruft::win32::file> (src)),
m_data (nullptr, UnmapViewOfFile)
{
// I would rather perform checks on filesize after mapping, but mapping
// requires a check for empty files before we perform the mapping to
// detect errors it throws in that specific situation.
DWORD hi_size;
DWORD lo_size = GetFileSize (m_file.native (), &hi_size);
if (lo_size == INVALID_FILE_SIZE)
::cruft::win32::error::throw_code ();
m_size = static_cast<uint64_t> (hi_size) << 32 | lo_size;
m_mapping.reset (
CreateFileMapping (
m_file,
nullptr,
mflags_to_protect (mflags),
0, 0,
nullptr
)
);
// Apparently Windows lacks the ability to map zero length files; fucking
// hell. Try not to collapse, but instead bail with a null mapping and
// pray the user doesn't do something stupid with the result.
if (!m_mapping) {
auto err = ::cruft::win32::error::last_code ();
if (err == ERROR_FILE_INVALID && m_size == 0)
return;
::cruft::win32::error::throw_code (err);
}
auto view = MapViewOfFile (
m_mapping,
fflags_to_access (fflags),
0, 0,
0
);
if (!view)
::cruft::win32::error::throw_code ();
m_data.reset (
static_cast<unsigned char*> (view)
);
}
//-----------------------------------------------------------------------------
mapped_file::mapped_file (
std::filesystem::path const &path,
int fflags,
int mflags
)
: mapped_file (
::cruft::win32::file (
path,
fflags_to_generic (fflags),
fflags == O_RDONLY ? FILE_SHARE_READ : 0,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN
),
fflags,
mflags
)
{ ; }
//-----------------------------------------------------------------------------
mapped_file::mapped_file (cruft::posix::fd const &src,
int fflags,
int mflags):
mapped_file (cruft::win32::file (src.dup ()),
fflags,
mflags)
{ };
static BOOL noop (LPCVOID) { return TRUE; }
//-----------------------------------------------------------------------------
mapped_file::mapped_file (mapped_file &&rhs) noexcept
: m_data (nullptr, noop)
{
std::swap (m_file, rhs.m_file);
std::swap (m_mapping, rhs.m_mapping);
std::swap (m_data, rhs.m_data);
std::swap (m_size, rhs.m_size);
}
///////////////////////////////////////////////////////////////////////////////
size_t
mapped_file::size (void) const
{
return m_size;
}
//-----------------------------------------------------------------------------
bool
mapped_file::empty (void) const
{
return size () == 0;
}
//-----------------------------------------------------------------------------
const uint8_t*
mapped_file::data (void) const &
{
return m_data.get ();
}
//-----------------------------------------------------------------------------
uint8_t*
mapped_file::data (void) &
{
return m_data.get ();
}
//-----------------------------------------------------------------------------
uint8_t*
mapped_file::begin (void) &
{
return data ();
}
//-----------------------------------------------------------------------------
uint8_t*
mapped_file::end (void) &
{
return data () + size ();
}
//-----------------------------------------------------------------------------
const uint8_t*
mapped_file::begin (void) const &
{
return cbegin ();
}
//-----------------------------------------------------------------------------
const uint8_t*
mapped_file::end (void) const &
{
return cend ();
}
//-----------------------------------------------------------------------------
const uint8_t*
mapped_file::cbegin (void) const &
{
return data ();
}
//-----------------------------------------------------------------------------
const uint8_t*
mapped_file::cend (void) const &
{
return data () + size ();
}