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

#include "include/Context.h"
#include "include/types.h"
#include "osd/osd_types.h"

class WritebackHandler {
 public:
  WritebackHandler() {}
  virtual ~WritebackHandler() {}

  virtual void read(const object_t& oid, uint64_t object_no,
		    const object_locator_t& oloc, uint64_t off, uint64_t len,
		    snapid_t snapid, bufferlist *pbl, uint64_t trunc_size,
		    __u32 trunc_seq, int op_flags,
                    const ZTracer::Trace &parent_trace, Context *onfinish) = 0;
  /**
   * check if a given extent read result may change due to a write
   *
   * Check if the content we see at the given read offset may change
   * due to a write to this object.
   *
   * @param oid object
   * @param read_off read offset
   * @param read_len read length
   * @param snapid read snapid
   */
  virtual bool may_copy_on_write(const object_t& oid, uint64_t read_off,
				 uint64_t read_len, snapid_t snapid) = 0;
  virtual ceph_tid_t write(const object_t& oid, const object_locator_t& oloc,
			   uint64_t off, uint64_t len,
			   const SnapContext& snapc,
			   const bufferlist &bl, ceph::real_time mtime,
			   uint64_t trunc_size, __u32 trunc_seq,
                           ceph_tid_t journal_tid,
                           const ZTracer::Trace &parent_trace,
                           Context *oncommit) = 0;

  virtual void overwrite_extent(const object_t& oid, uint64_t off, uint64_t len,
                                ceph_tid_t original_journal_tid,
                                ceph_tid_t new_journal_tid) {}

  virtual bool can_scattered_write() { return false; }
  virtual ceph_tid_t write(const object_t& oid, const object_locator_t& oloc,
			   vector<pair<uint64_t, bufferlist> >& io_vec,
			   const SnapContext& snapc, ceph::real_time mtime,
			   uint64_t trunc_size, __u32 trunc_seq,
			   Context *oncommit) {
    return 0;
  }
};

#endif