/*-
 * Copyright (c) 2014-2016 MongoDB, Inc.
 * Copyright (c) 2008-2014 WiredTiger, Inc.
 *	All rights reserved.
 *
 * See the file LICENSE for redistribution information.
 */

/*
 * Number of directory entries can grow dynamically.
 */
#define	WT_DIR_ENTRY	32

#define	WT_DIRLIST_EXCLUDE	0x1	/* Exclude files matching prefix */
#define	WT_DIRLIST_INCLUDE	0x2	/* Include files matching prefix */

#define	WT_SYSCALL_RETRY(call, ret) do {				\
	int __retry;							\
	for (__retry = 0; __retry < 10; ++__retry) {			\
		if ((call) == 0) {					\
			(ret) = 0;					\
			break;						\
		}							\
		switch ((ret) = __wt_errno()) {				\
		case 0:							\
			/* The call failed but didn't set errno. */	\
			(ret) = WT_ERROR;				\
			break;						\
		case EAGAIN:						\
		case EBUSY:						\
		case EINTR:						\
		case EIO:						\
		case EMFILE:						\
		case ENFILE:						\
		case ENOSPC:						\
			__wt_sleep(0L, 50000L);				\
			continue;					\
		default:						\
			break;						\
		}							\
		break;							\
	}								\
} while (0)

#define	WT_TIMEDIFF_NS(end, begin)					\
	(WT_BILLION * (uint64_t)((end).tv_sec - (begin).tv_sec) +	\
	    (uint64_t)(end).tv_nsec - (uint64_t)(begin).tv_nsec)
#define	WT_TIMEDIFF_US(end, begin)					\
	(WT_TIMEDIFF_NS((end), (begin)) / WT_THOUSAND)
#define	WT_TIMEDIFF_MS(end, begin)					\
	(WT_TIMEDIFF_NS((end), (begin)) / WT_MILLION)
#define	WT_TIMEDIFF_SEC(end, begin)					\
	(WT_TIMEDIFF_NS((end), (begin)) / WT_BILLION)

#define	WT_TIMECMP(t1, t2)						\
	((t1).tv_sec < (t2).tv_sec ? -1 :				\
	     (t1).tv_sec == (t2.tv_sec) ?				\
	     (t1).tv_nsec < (t2).tv_nsec ? -1 :				\
	     (t1).tv_nsec == (t2).tv_nsec ? 0 : 1 : 1)

/*
 * The underlying OS calls return ENOTSUP if posix_fadvise functionality isn't
 * available, but WiredTiger uses the POSIX flag names in the API. Use distinct
 * values so the underlying code can distinguish.
 */
#ifndef	POSIX_FADV_DONTNEED
#define	POSIX_FADV_DONTNEED	0x01
#endif
#ifndef	POSIX_FADV_WILLNEED
#define	POSIX_FADV_WILLNEED	0x02
#endif

#define	WT_OPEN_CREATE		0x001	/* Create is OK */
#define	WT_OPEN_EXCLUSIVE	0x002	/* Exclusive open */
#define	WT_OPEN_FIXED		0x004	/* Path isn't relative to home */
#define	WT_OPEN_READONLY	0x008	/* Readonly open */
#define	WT_STREAM_APPEND	0x010	/* Open a stream: append */
#define	WT_STREAM_LINE_BUFFER	0x020	/* Line buffer the stream */
#define	WT_STREAM_READ		0x040	/* Open a stream: read */
#define	WT_STREAM_WRITE		0x080	/* Open a stream: write */

struct __wt_fh {
	const char *name;			/* File name */
	uint64_t name_hash;			/* Hash of name */
	TAILQ_ENTRY(__wt_fh) q;			/* List of open handles */
	TAILQ_ENTRY(__wt_fh) hashq;		/* Hashed list of handles */

	u_int	ref;				/* Reference count */

	/*
	 * Underlying file system handle support.
	 */
#ifdef _WIN32
	HANDLE filehandle;			/* Windows file handle */
	HANDLE filehandle_secondary;		/* Windows file handle
						   for file size changes */
#else
	int	 fd;				/* POSIX file handle */
#endif
	FILE	*fp;				/* ANSI C stdio handle */

	/*
	 * Underlying in-memory handle support.
	 */
	size_t	 off;				/* Read/write offset */
	WT_ITEM  buf;				/* Data */

	bool	 direct_io;			/* O_DIRECT configured */

	enum {					/* file extend configuration */
	    WT_FALLOCATE_AVAILABLE,
	    WT_FALLOCATE_NOT_AVAILABLE,
	    WT_FALLOCATE_POSIX,
	    WT_FALLOCATE_STD,
	    WT_FALLOCATE_SYS } fallocate_available;
	bool fallocate_requires_locking;

#define	WT_FH_FLUSH_ON_CLOSE	0x01		/* Flush when closing */
#define	WT_FH_IN_MEMORY		0x02		/* In-memory, don't remove */
	uint32_t flags;

	int (*fh_advise)(WT_SESSION_IMPL *, WT_FH *, wt_off_t, wt_off_t, int);
	int (*fh_allocate)(WT_SESSION_IMPL *, WT_FH *, wt_off_t, wt_off_t);
	int (*fh_close)(WT_SESSION_IMPL *, WT_FH *);
	int (*fh_getc)(WT_SESSION_IMPL *, WT_FH *, int *);
	int (*fh_lock)(WT_SESSION_IMPL *, WT_FH *, bool);
	int (*fh_map)(WT_SESSION_IMPL *, WT_FH *, void *, size_t *, void **);
	int (*fh_map_discard)(WT_SESSION_IMPL *, WT_FH *, void *, size_t);
	int (*fh_map_preload)(WT_SESSION_IMPL *, WT_FH *, const void *, size_t);
	int (*fh_map_unmap)(
	    WT_SESSION_IMPL *, WT_FH *, void *, size_t, void **);
	int (*fh_printf)(WT_SESSION_IMPL *, WT_FH *, const char *, va_list);
	int (*fh_read)(WT_SESSION_IMPL *, WT_FH *, wt_off_t, size_t, void *);
	int (*fh_size)(WT_SESSION_IMPL *, WT_FH *, wt_off_t *);
	int (*fh_sync)(WT_SESSION_IMPL *, WT_FH *, bool);
	int (*fh_truncate)(WT_SESSION_IMPL *, WT_FH *, wt_off_t);
	int (*fh_write)(
	    WT_SESSION_IMPL *, WT_FH *, wt_off_t, size_t, const void *);
};