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/* Copyright (C) 2011 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* emulate POSIX asynchronous I/O on Windows.
*/
#ifndef INCLUDED_WAIO
#define INCLUDED_WAIO
#include "lib/status.h"
#include "lib/os_path.h"
#include "lib/posix/posix_time.h" // timespec
#include "lib/sysdep/os/win/wposix/wposix_types.h"
// Note: transfer buffers, offsets, and lengths must be sector-aligned
// (we don't bother copying to an align buffer because our block cache
// already requires splitting IOs into naturally-aligned blocks)
//
// <signal.h>
//
union sigval // unused
{
int sival_int; // Integer signal value.
void* sival_ptr; // Pointer signal value.
};
struct sigevent // unused
{
int sigev_notify; // notification mode
int sigev_signo; // signal number
union sigval sigev_value; // signal value
void (*sigev_notify_function)(union sigval);
};
//
// <aio.h>
//
struct aiocb
{
int aio_fildes; // File descriptor.
off_t aio_offset; // File offset.
volatile void* aio_buf; // Location of buffer.
size_t aio_nbytes; // Length of transfer.
int aio_reqprio; // Request priority offset. (unused)
struct sigevent aio_sigevent; // Signal number and value. (unused)
int aio_lio_opcode; // Operation to be performed.
// internal use only; must be zero-initialized before
// calling the first aio_read/aio_write/lio_listio
// (aio_return resets it to 0)
void* ovl;
};
enum
{
// aio_cancel return
AIO_ALLDONE, // None of the requested operations could be canceled since they are already complete.
AIO_CANCELED, // All requested operations have been canceled.
AIO_NOTCANCELED, // Some of the requested operations could not be canceled since they are in progress.
// lio_listio mode
LIO_WAIT, // wait until all I/O is complete
LIO_NOWAIT,
// lio_listio ops
LIO_NOP,
LIO_READ,
LIO_WRITE
};
extern int aio_read(struct aiocb*);
extern int aio_write(struct aiocb*);
extern int lio_listio(int, struct aiocb* const[], int, struct sigevent*);
// (if never called, IOCP notifications will pile up.)
extern int aio_suspend(const struct aiocb* const[], int, const struct timespec*);
// @return status of transfer (0 or an errno)
extern int aio_error(const struct aiocb*);
// @return bytes transferred or -1 on error.
// frees internal storage related to the request and MUST be called
// exactly once for each aiocb after aio_error != EINPROGRESS.
extern ssize_t aio_return(struct aiocb*);
extern int aio_cancel(int, struct aiocb*);
extern int aio_fsync(int, struct aiocb*);
// open the file for aio (not possible via _wsopen_s since it cannot
// set FILE_FLAG_NO_BUFFERING).
//
// @return the smallest available file descriptor. NB: these numbers
// are not 0-based to avoid confusion with lowio descriptors and
// must only be used with waio functions.
extern Status waio_open(const OsPath& pathname, int oflag, ...);
extern Status waio_close(int fd);
// call this before writing a large file to preallocate clusters, thus
// reducing fragmentation.
//
// @param fd file descriptor from _wsopen_s OR waio_open
// @param size is rounded up to a multiple of maxSectorSize (required by
// SetEndOfFile; this could be avoided by using the undocumented
// NtSetInformationFile or SetFileInformationByHandle on Vista and later).
// use wtruncate after I/O is complete to chop off the excess padding.
//
// NB: writes that extend a file (i.e. ALL WRITES when creating new files)
// are synchronous, which prevents overlapping I/O and other work.
// (http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B156932)
// if Windows XP and the SE_MANAGE_VOLUME_NAME privileges are available,
// this function sets the valid data length to avoid the synchronous zero-fill.
// to avoid exposing the previous disk contents until the application
// successfully writes to the file, deny sharing when opening the file.
LIB_API Status waio_Preallocate(int fd, off_t size);
#endif // #ifndef INCLUDED_WAIO
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