// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab

#ifndef __CEPH_OSD_CHAIN_XATTR_H
#define __CEPH_OSD_CHAIN_XATTR_H

#include "include/compat.h"
#include <errno.h>
#include <stdio.h>
#include "common/xattr.h"
#include "include/assert.h"
#include "include/buffer_fwd.h"

#if defined(__linux__)
#include <linux/limits.h>
#define CHAIN_XATTR_MAX_NAME_LEN ((XATTR_NAME_MAX + 1) / 2)
#elif defined(__APPLE__)
#include <sys/xattr.h>
#define CHAIN_XATTR_MAX_NAME_LEN ((XATTR_MAXNAMELEN + 1) / 2)
#else
#define CHAIN_XATTR_MAX_NAME_LEN  128
#endif

#define CHAIN_XATTR_MAX_BLOCK_LEN 2048

/*
 * XFS will only inline xattrs < 255 bytes, so for xattrs that are
 * likely to fit in the inode, stripe over short xattrs.
 */
#define CHAIN_XATTR_SHORT_BLOCK_LEN 250
#define CHAIN_XATTR_SHORT_LEN_THRESHOLD 1000

// wrappers to hide annoying errno handling.

static inline int sys_fgetxattr(int fd, const char *name, void *val, size_t size)
{
  int r = ::ceph_os_fgetxattr(fd, name, val, size);
  return (r < 0 ? -errno : r);
}
static inline int sys_getxattr(const char *fn, const char *name, void *val, size_t size)
{
  int r = ::ceph_os_getxattr(fn, name, val, size);
  return (r < 0 ? -errno : r);
}

static inline int sys_setxattr(const char *fn, const char *name, const void *val, size_t size)
{
  int r = ::ceph_os_setxattr(fn, name, val, size);
  return (r < 0 ? -errno : r);
}
static inline int sys_fsetxattr(int fd, const char *name, const void *val, size_t size)
{
  int r = ::ceph_os_fsetxattr(fd, name, val, size);
  return (r < 0 ? -errno : r);
}

static inline int sys_listxattr(const char *fn, char *names, size_t len)
{
  int r = ::ceph_os_listxattr(fn, names, len);
  return (r < 0 ? -errno : r);
}
static inline int sys_flistxattr(int fd, char *names, size_t len)
{
  int r = ::ceph_os_flistxattr(fd, names, len);
  return (r < 0 ? -errno : r);
}

static inline int sys_removexattr(const char *fn, const char *name)
{
  int r = ::ceph_os_removexattr(fn, name);
  return (r < 0 ? -errno : r);
}
static inline int sys_fremovexattr(int fd, const char *name)
{
  int r = ::ceph_os_fremovexattr(fd, name);
  return (r < 0 ? -errno : r);
}


// wrappers to chain large values across multiple xattrs

int chain_getxattr(const char *fn, const char *name, void *val, size_t size);
int chain_getxattr_buf(const char *fn, const char *name, bufferptr *bp);
int chain_fgetxattr(int fd, const char *name, void *val, size_t size);

int get_xattr_block_size(size_t size);
void get_raw_xattr_name(const char *name, int i, char *raw_name, int raw_len);

template <bool skip_chain_cleanup=false, bool ensure_single_attr=false>
int chain_setxattr(
  const char *fn, const char *name, const void *val, size_t size)
{
  int i = 0, pos = 0;
  char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16];
  int ret = 0;
  size_t max_chunk_size =
    ensure_single_attr ? size : get_xattr_block_size(size);

  static_assert(
    !skip_chain_cleanup || ensure_single_attr,
    "skip_chain_cleanup must imply ensure_single_attr");

  do {
    size_t chunk_size = (size < max_chunk_size ? size : max_chunk_size);
    get_raw_xattr_name(name, i, raw_name, sizeof(raw_name));
    size -= chunk_size;

    int r = sys_setxattr(fn, raw_name, (char *)val + pos, chunk_size);
    if (r < 0) {
      ret = r;
      break;
    }
    pos  += chunk_size;
    ret = pos;
    i++;
    assert(size == 0 || !ensure_single_attr);
  } while (size);

  if (ret >= 0 && !skip_chain_cleanup) {
    int r;
    do {
      get_raw_xattr_name(name, i, raw_name, sizeof(raw_name));
      r = sys_removexattr(fn, raw_name);
      if (r < 0 && r != -ENODATA)
	ret = r;
      i++;
    } while (r != -ENODATA);
  }

  return ret;
}

template <bool skip_chain_cleanup=false, bool ensure_single_attr=false>
int chain_fsetxattr(
  int fd, const char *name, const void *val, size_t size)
{
  int i = 0, pos = 0;
  char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16];
  int ret = 0;
  size_t max_chunk_size =
    ensure_single_attr ? size : get_xattr_block_size(size);

  static_assert(
    !skip_chain_cleanup || ensure_single_attr,
    "skip_chain_cleanup must imply ensure_single_attr");

  do {
    size_t chunk_size = (size < max_chunk_size ? size : max_chunk_size);
    get_raw_xattr_name(name, i, raw_name, sizeof(raw_name));
    size -= chunk_size;

    int r = sys_fsetxattr(fd, raw_name, (char *)val + pos, chunk_size);
    if (r < 0) {
      ret = r;
      break;
    }
    pos  += chunk_size;
    ret = pos;
    i++;
    assert(size == 0 || !ensure_single_attr);
  } while (size);

  if (ret >= 0 && !skip_chain_cleanup) {
    int r;
    do {
      get_raw_xattr_name(name, i, raw_name, sizeof(raw_name));
      r = sys_fremovexattr(fd, raw_name);
      if (r < 0 && r != -ENODATA)
	ret = r;
      i++;
    } while (r != -ENODATA);
  }

  return ret;
}

int chain_listxattr(const char *fn, char *names, size_t len);
int chain_flistxattr(int fd, char *names, size_t len);
int chain_removexattr(const char *fn, const char *name);
int chain_fremovexattr(int fd, const char *name);

#endif