/**
 * =========================================================================
 * File        : file.cpp
 * Project     : 0 A.D.
 * Description : simple POSIX file wrapper.
 * =========================================================================
 */

#include "precompiled.h"
#include "file.h"

#include "lib/file/common/file_stats.h"
#include "lib/file/path.h"


ERROR_ASSOCIATE(ERR::FILE_ACCESS, "Insufficient access rights to open file", EACCES);
ERROR_ASSOCIATE(ERR::IO, "Error during IO", EIO);


File::File()
{
}


File::~File()
{
	Close();
}


LibError File::Open(const Path& pathname, char mode)
{
	debug_assert(mode == 'w' || mode == 'r');

	m_pathname = pathname;
	m_mode = mode;

	int oflag = (mode == 'r')? O_RDONLY : O_WRONLY|O_CREAT|O_TRUNC;
#if OS_WIN
	oflag |= O_BINARY_NP;
#endif
	m_fd = open(m_pathname.external_file_string().c_str(), oflag, S_IRWXO|S_IRWXU|S_IRWXG);
	if(m_fd < 0)
		WARN_RETURN(ERR::FILE_ACCESS);

	stats_open();
	return INFO::OK;
}


void File::Close()
{
	m_mode = '\0';

	close(m_fd);
	m_fd = 0;
}


LibError File::Issue(aiocb& req, off_t alignedOfs, u8* alignedBuf, size_t alignedSize) const
{
	memset(&req, 0, sizeof(req));
	req.aio_lio_opcode = (m_mode == 'w')? LIO_WRITE : LIO_READ;
	req.aio_buf        = (volatile void*)alignedBuf;
	req.aio_fildes     = m_fd;
	req.aio_offset     = alignedOfs;
	req.aio_nbytes     = alignedSize;
	struct sigevent* sig = 0;	// no notification signal
	aiocb* const reqs = &req;
	if(lio_listio(LIO_NOWAIT, &reqs, 1, sig) != 0)
		return LibError_from_errno();
	return INFO::OK;
}


/*static*/ LibError File::WaitUntilComplete(aiocb& req, u8*& alignedBuf, size_t& alignedSize)
{
	// wait for transfer to complete.
	while(aio_error(&req) == EINPROGRESS)
	{
		aiocb* const reqs = &req;
		aio_suspend(&reqs, 1, (timespec*)0);	// wait indefinitely
	}

	const ssize_t bytesTransferred = aio_return(&req);
	if(bytesTransferred == -1)	// transfer failed
		WARN_RETURN(ERR::IO);

	alignedBuf = (u8*)req.aio_buf;	// cast from volatile void*
	alignedSize = bytesTransferred;
	return INFO::OK;
}


LibError File::IO(off_t ofs, u8* buf, size_t size) const
{
	ScopedIoMonitor monitor;

	lseek(m_fd, ofs, SEEK_SET);

	errno = 0;
	const ssize_t ret = (m_mode == 'w')? write(m_fd, buf, size) : read(m_fd, buf, size);
	if(ret < 0)
		return LibError_from_errno();

	const size_t totalTransferred = (size_t)ret;
	if(totalTransferred != size)
		WARN_RETURN(ERR::IO);

	monitor.NotifyOfSuccess(FI_LOWIO, m_mode, totalTransferred);
	return INFO::OK;
}


LibError File::Write(off_t ofs, const u8* buf, size_t size) const
{
	return IO(ofs, const_cast<u8*>(buf), size);
}


LibError File::Read(off_t ofs, u8* buf, size_t size) const
{
	return IO(ofs, buf, size);
}