librados.hpp

#ifndef __LIBRADOS_HPP
#define __LIBRADOS_HPP

#include <stdbool.h>
#include <string>
#include <list>
#include <map>
#include <set>
#include <vector>
#include <utility>
#include "memory.h"
#include "buffer.h"

#include "librados.h"
#include "rados_types.hpp"

namespace librados
{
  using ceph::bufferlist;

  struct AioCompletionImpl;
  class IoCtx;
  struct IoCtxImpl;
  class ObjectOperationImpl;
  struct ObjListCtx;
  struct PoolAsyncCompletionImpl;
  class RadosClient;

  typedef void *list_ctx_t;
  typedef uint64_t auid_t;
  typedef void *config_t;

  struct cluster_stat_t {
    uint64_t kb, kb_used, kb_avail;
    uint64_t num_objects;
  };

  struct pool_stat_t {
    uint64_t num_bytes;    // in bytes
    uint64_t num_kb;       // in KB
    uint64_t num_objects;
    uint64_t num_object_clones;
    uint64_t num_object_copies;  // num_objects * num_replicas
    uint64_t num_objects_missing_on_primary;
    uint64_t num_objects_unfound;
    uint64_t num_objects_degraded;
    uint64_t num_rd, num_rd_kb, num_wr, num_wr_kb;
  };

  typedef struct {
    std::string client;
    std::string cookie;
    std::string address;
  } locker_t;

  typedef std::map<std::string, pool_stat_t> stats_map;

  typedef void *completion_t;
  typedef void (*callback_t)(completion_t cb, void *arg);

  class ObjectIterator : public std::iterator <std::forward_iterator_tag, std::string> {
  public:
    static const ObjectIterator __EndObjectIterator;
    ObjectIterator() {}
    ObjectIterator(ObjListCtx *ctx_);
    ~ObjectIterator();
    ObjectIterator(const ObjectIterator &rhs);
    ObjectIterator& operator=(const ObjectIterator& rhs);

    bool operator==(const ObjectIterator& rhs) const;
    bool operator!=(const ObjectIterator& rhs) const;
    const std::pair<std::string, std::string>& operator*() const;
    const std::pair<std::string, std::string>* operator->() const;
    ObjectIterator &operator++(); // Preincrement
    ObjectIterator operator++(int); // Postincrement
    friend class IoCtx;

    /// get current hash position of the iterator, rounded to the current pg
    uint32_t get_pg_hash_position() const;

    /// move the iterator to a given hash position.  this may (will!) be rounded to the nearest pg.
    uint32_t seek(uint32_t pos);

  private:
    void get_next();
    ceph::shared_ptr < ObjListCtx > ctx;
    std::pair<std::string, std::string> cur_obj;
  };

  class WatchCtx {
  public:
    virtual ~WatchCtx();
    virtual void notify(uint8_t opcode, uint64_t ver, bufferlist& bl) = 0;
  };

  struct AioCompletion {
    AioCompletion(AioCompletionImpl *pc_) : pc(pc_) {}
    int set_complete_callback(void *cb_arg, callback_t cb);
    int set_safe_callback(void *cb_arg, callback_t cb);
    int wait_for_complete();
    int wait_for_safe();
    int wait_for_complete_and_cb();
    int wait_for_safe_and_cb();
    bool is_complete();
    bool is_safe();
    bool is_complete_and_cb();
    bool is_safe_and_cb();
    int get_return_value();
    int get_version() __attribute__ ((deprecated));
    uint64_t get_version64();
    void release();
    AioCompletionImpl *pc;
  };

  struct PoolAsyncCompletion {
    PoolAsyncCompletion(PoolAsyncCompletionImpl *pc_) : pc(pc_) {}
    int set_callback(void *cb_arg, callback_t cb);
    int wait();
    bool is_complete();
    int get_return_value();
    void release();
    PoolAsyncCompletionImpl *pc;
  };

  /**
   * These are per-op flags which may be different among
   * ops added to an ObjectOperation.
   */
  enum ObjectOperationFlags {
    OP_EXCL =   LIBRADOS_OP_FLAG_EXCL,
    OP_FAILOK = LIBRADOS_OP_FLAG_FAILOK,
  };

  class ObjectOperationCompletion {
  public:
    virtual ~ObjectOperationCompletion() {}
    virtual void handle_completion(int r, bufferlist& outbl) = 0;
  };

  /**
   * These flags apply to the ObjectOperation as a whole.
   *
   * BALANCE_READS and LOCALIZE_READS should only be used
   * when reading from data you're certain won't change,
   * like a snapshot, or where eventual consistency is ok.
   *
   * ORDER_READS_WRITES will order reads the same way writes are
   * ordered (e.g., waiting for degraded objects).  In particular, it
   * will make a write followed by a read sequence be preserved.
   *
   * IGNORE_CACHE will skip the caching logic on the OSD that normally
   * handles promotion of objects between tiers.  This allows an operation
   * to operate (or read) the cached (or uncached) object, even if it is
   * not coherent.
   *
   * IGNORE_OVERLAY will ignore the pool overlay tiering metadata and
   * process the op directly on the destination pool.  This is useful
   * for CACHE_FLUSH and CACHE_EVICT operations.
   */
  enum ObjectOperationGlobalFlags {
    OPERATION_NOFLAG         = 0,
    OPERATION_BALANCE_READS  = 1,
    OPERATION_LOCALIZE_READS = 2,
    OPERATION_ORDER_READS_WRITES = 4,
    OPERATION_IGNORE_CACHE = 8,
    OPERATION_SKIPRWLOCKS = 16,
    OPERATION_IGNORE_OVERLAY = 32,
  };

  /*
   * ObjectOperation : compound object operation
   * Batch multiple object operations into a single request, to be applied
   * atomically.
   */
  class ObjectOperation
  {
  public:
    ObjectOperation();
    virtual ~ObjectOperation();

    size_t size();
    void set_op_flags(ObjectOperationFlags flags);

    void cmpxattr(const char *name, uint8_t op, const bufferlist& val);
    void cmpxattr(const char *name, uint8_t op, uint64_t v);
    void src_cmpxattr(const std::string& src_oid,
		      const char *name, int op, const bufferlist& val);
    void src_cmpxattr(const std::string& src_oid,
		      const char *name, int op, uint64_t v);
    void exec(const char *cls, const char *method, bufferlist& inbl);
    void exec(const char *cls, const char *method, bufferlist& inbl, bufferlist *obl, int *prval);
    void exec(const char *cls, const char *method, bufferlist& inbl, ObjectOperationCompletion *completion);
    /**
     * Guard operation with a check that object version == ver
     *
     * @param ver [in] version to check
     */
    void assert_version(uint64_t ver);

    /**
     * Guard operatation with a check that the object already exists
     */
    void assert_exists();

    /**
     * get key/value pairs for specified keys
     *
     * @param assertions [in] comparison assertions
     * @param prval [out] place error code in prval upon completion
     *
     * assertions has the form of mappings from keys to (comparison rval, assertion)
     * The assertion field may be CEPH_OSD_CMPXATTR_OP_[GT|LT|EQ].
     *
     * That is, to assert that the value at key 'foo' is greater than 'bar':
     *
     * ObjectReadOperation op;
     * int r;
     * map<string, pair<bufferlist, int> > assertions;
     * bufferlist bar(string('bar'));
     * assertions['foo'] = make_pair(bar, CEPH_OSD_CMP_XATTR_OP_GT);
     * op.omap_cmp(assertions, &r);
     */
    void omap_cmp(
      const std::map<std::string, std::pair<bufferlist, int> > &assertions,
      int *prval);

  protected:
    ObjectOperationImpl *impl;
    ObjectOperation(const ObjectOperation& rhs);
    ObjectOperation& operator=(const ObjectOperation& rhs);
    friend class IoCtx;
    friend class Rados;
  };

  /*
   * ObjectWriteOperation : compound object write operation
   * Batch multiple object operations into a single request, to be applied
   * atomically.
   */
  class ObjectWriteOperation : public ObjectOperation
  {
  protected:
    time_t *pmtime;
  public:
    ObjectWriteOperation() : pmtime(NULL) {}
    ~ObjectWriteOperation() {}

    void mtime(time_t *pt) {
      pmtime = pt;
    }

    void create(bool exclusive);
    void create(bool exclusive, const std::string& category);
    void write(uint64_t off, const bufferlist& bl);
    void write_full(const bufferlist& bl);
    void append(const bufferlist& bl);
    void remove();
    void truncate(uint64_t off);
    void zero(uint64_t off, uint64_t len);
    void rmxattr(const char *name);
    void setxattr(const char *name, const bufferlist& bl);
    void tmap_update(const bufferlist& cmdbl);
    void tmap_put(const bufferlist& bl);
    void clone_range(uint64_t dst_off,
                     const std::string& src_oid, uint64_t src_off,
                     size_t len);
    void selfmanaged_snap_rollback(uint64_t snapid);

    /**
     * Rollback an object to the specified snapshot id
     *
     * Used with pool snapshots
     *
     * @param snapid [in] snopshot id specified
     */
    void snap_rollback(uint64_t snapid);

    /**
     * set keys and values according to map
     *
     * @param map [in] keys and values to set
     */
    void omap_set(const std::map<std::string, bufferlist> &map);

    /**
     * set header
     *
     * @param bl [in] header to set
     */
    void omap_set_header(const bufferlist &bl);

    /**
     * Clears omap contents
     */
    void omap_clear();

    /**
     * Clears keys in to_rm
     *
     * @param to_rm [in] keys to remove
     */
    void omap_rm_keys(const std::set<std::string> &to_rm);

    /**
     * Copy an object
     *
     * Copies an object from another location.  The operation is atomic in that
     * the copy either succeeds in its entirety or fails (e.g., because the
     * source object was modified while the copy was in progress).
     *
     * @param src source object name
     * @param src_ioctx ioctx for the source object
     * @param version current version of the source object
     */
    void copy_from(const std::string& src, const IoCtx& src_ioctx,
		   uint64_t src_version);

    /**
     * undirty an object
     *
     * Clear an objects dirty flag
     */
    void undirty();

    /**
     * Set allocation hint for an object
     *
     * @param expected_object_size expected size of the object, in bytes
     * @param expected_write_size expected size of writes to the object, in bytes
     */
    void set_alloc_hint(uint64_t expected_object_size,
                        uint64_t expected_write_size);

    friend class IoCtx;
  };

  /*
   * ObjectReadOperation : compound object operation that return value
   * Batch multiple object operations into a single request, to be applied
   * atomically.
   */
  class ObjectReadOperation : public ObjectOperation
  {
  public:
    ObjectReadOperation() {}
    ~ObjectReadOperation() {}

    void stat(uint64_t *psize, time_t *pmtime, int *prval);
    void getxattr(const char *name, bufferlist *pbl, int *prval);
    void getxattrs(std::map<std::string, bufferlist> *pattrs, int *prval);
    void read(size_t off, uint64_t len, bufferlist *pbl, int *prval);
    /**
     * see aio_sparse_read()
     */
    void sparse_read(uint64_t off, uint64_t len, std::map<uint64_t,uint64_t> *m,
                    bufferlist *data_bl, int *prval);
    void tmap_get(bufferlist *pbl, int *prval);

    /**
     * omap_get_vals: keys and values from the object omap
     *
     * Get up to max_return keys and values beginning after start_after
     *
     * @param start_after [in] list no keys smaller than start_after
     * @parem max_return [in] list no more than max_return key/value pairs
     * @param out_vals [out] place returned values in out_vals on completion
     * @param prval [out] place error code in prval upon completion
     */
    void omap_get_vals(
      const std::string &start_after,
      uint64_t max_return,
      std::map<std::string, bufferlist> *out_vals,
      int *prval);

    /**
     * omap_get_vals: keys and values from the object omap
     *
     * Get up to max_return keys and values beginning after start_after
     *
     * @param start_after [in] list keys starting after start_after
     * @param filter_prefix [in] list only keys beginning with filter_prefix
     * @parem max_return [in] list no more than max_return key/value pairs
     * @param out_vals [out] place returned values in out_vals on completion
     * @param prval [out] place error code in prval upon completion
     */
    void omap_get_vals(
      const std::string &start_after,
      const std::string &filter_prefix,
      uint64_t max_return,
      std::map<std::string, bufferlist> *out_vals,
      int *prval);


    /**
     * omap_get_keys: keys from the object omap
     *
     * Get up to max_return keys beginning after start_after
     *
     * @param start_after [in] list keys starting after start_after
     * @parem max_return [in] list no more than max_return keys
     * @param out_keys [out] place returned values in out_keys on completion
     * @param prval [out] place error code in prval upon completion
     */
    void omap_get_keys(const std::string &start_after,
                       uint64_t max_return,
                       std::set<std::string> *out_keys,
                       int *prval);

    /**
     * omap_get_header: get header from object omap
     *
     * @param header [out] place header here upon completion
     * @param prval [out] place error code in prval upon completion
     */
    void omap_get_header(bufferlist *header, int *prval);

    /**
     * get key/value pairs for specified keys
     *
     * @param to_get [in] keys to get
     * @param out_vals [out] place key/value pairs found here on completion
     * @param prval [out] place error code in prval upon completion
     */
    void omap_get_vals_by_keys(const std::set<std::string> &keys,
			       std::map<std::string, bufferlist> *map,
			       int *prval);

    /**
     * list_watchers: Get list watchers of object
     *
     * @param out_watchers [out] place returned values in out_watchers on completion
     * @param prval [out] place error code in prval upon completion
     */
    void list_watchers(std::list<obj_watch_t> *out_watchers, int *prval);

    /**
     * list snapshot clones associated with a logical object
     *
     * This will include a record for each version of the object,
     * include the "HEAD" (which will have a cloneid of SNAP_HEAD).
     * Each clone includes a vector of snap ids for which it is
     * defined to exist.
     *
     * NOTE: this operation must be submitted from an IoCtx with a
     * read snapid of SNAP_DIR for reliable results.
     *
     * @param out_snaps [out] pointer to resulting snap_set_t
     * @param prval [out] place error code in prval upon completion
     */
    void list_snaps(snap_set_t *out_snaps, int *prval);

    /**
     * query dirty state of an object
     *
     * @param out_dirty [out] pointer to resulting bool
     * @param prval [out] place error code in prval upon completion
     */
    void is_dirty(bool *isdirty, int *prval);

    /**
     * flush a cache tier object to backing tier; will block racing
     * updates.
     *
     * This should be used in concert with OPERATION_IGNORE_CACHE to avoid
     * triggering a promotion.
     */
    void cache_flush();

    /**
     * Flush a cache tier object to backing tier; will EAGAIN if we race
     * with an update.  Must be used with the SKIPRWLOCKS flag.
     *
     * This should be used in concert with OPERATION_IGNORE_CACHE to avoid
     * triggering a promotion.
     */
    void cache_try_flush();

    /**
     * evict a clean cache tier object
     *
     * This should be used in concert with OPERATION_IGNORE_CACHE to avoid
     * triggering a promote on the OSD (that is then evicted).
     */
    void cache_evict();
  };

  /* IoCtx : This is a context in which we can perform I/O.
   * It includes a Pool,
   *
   * Typical use (error checking omitted):
   *
   * IoCtx p;
   * rados.ioctx_create("my_pool", p);
   * p->stat(&stats);
   * ... etc ...
   */
  class IoCtx
  {
  public:
    IoCtx();
    static void from_rados_ioctx_t(rados_ioctx_t p, IoCtx &pool);
    IoCtx(const IoCtx& rhs);
    IoCtx& operator=(const IoCtx& rhs);

    ~IoCtx();

    // Close our pool handle
    void close();

    // deep copy
    void dup(const IoCtx& rhs);

    // set pool auid
    int set_auid(uint64_t auid_);

    // set pool auid
    int set_auid_async(uint64_t auid_, PoolAsyncCompletion *c);

    // get pool auid
    int get_auid(uint64_t *auid_);

    std::string get_pool_name();

    bool pool_requires_alignment();
    uint64_t pool_required_alignment();

    // create an object
    int create(const std::string& oid, bool exclusive);
    int create(const std::string& oid, bool exclusive, const std::string& category);

    /**
     * write bytes to an object at a specified offset
     *
     * NOTE: this call steals the contents of @param bl.
     */
    int write(const std::string& oid, bufferlist& bl, size_t len, uint64_t off);
    /**
     * append bytes to an object
     *
     * NOTE: this call steals the contents of @param bl.
     */
    int append(const std::string& oid, bufferlist& bl, size_t len);
    /**
     * replace object contents with provided data
     *
     * NOTE: this call steals the contents of @param bl.
     */
    int write_full(const std::string& oid, bufferlist& bl);
    int clone_range(const std::string& dst_oid, uint64_t dst_off,
                   const std::string& src_oid, uint64_t src_off,
                   size_t len);
    int read(const std::string& oid, bufferlist& bl, size_t len, uint64_t off);
    int remove(const std::string& oid);
    int trunc(const std::string& oid, uint64_t size);
    int mapext(const std::string& o, uint64_t off, size_t len, std::map<uint64_t,uint64_t>& m);
    int sparse_read(const std::string& o, std::map<uint64_t,uint64_t>& m, bufferlist& bl, size_t len, uint64_t off);
    int getxattr(const std::string& oid, const char *name, bufferlist& bl);
    int getxattrs(const std::string& oid, std::map<std::string, bufferlist>& attrset);
    int setxattr(const std::string& oid, const char *name, bufferlist& bl);
    int rmxattr(const std::string& oid, const char *name);
    int stat(const std::string& oid, uint64_t *psize, time_t *pmtime);
    int exec(const std::string& oid, const char *cls, const char *method,
	     bufferlist& inbl, bufferlist& outbl);
    /**
     * modify object tmap based on encoded update sequence
     *
     * NOTE: this call steals the contents of @param bl
     */
    int tmap_update(const std::string& oid, bufferlist& cmdbl);
    /**
     * replace object contents with provided encoded tmap data
     *
     * NOTE: this call steals the contents of @param bl
     */
    int tmap_put(const std::string& oid, bufferlist& bl);
    int tmap_get(const std::string& oid, bufferlist& bl);
    int tmap_to_omap(const std::string& oid, bool nullok=false);

    int omap_get_vals(const std::string& oid,
                      const std::string& start_after,
                      uint64_t max_return,
                      std::map<std::string, bufferlist> *out_vals);
    int omap_get_vals(const std::string& oid,
                      const std::string& start_after,
                      const std::string& filter_prefix,
                      uint64_t max_return,
                      std::map<std::string, bufferlist> *out_vals);
    int omap_get_keys(const std::string& oid,
                      const std::string& start_after,
                      uint64_t max_return,
                      std::set<std::string> *out_keys);
    int omap_get_header(const std::string& oid,
                        bufferlist *bl);
    int omap_get_vals_by_keys(const std::string& oid,
                              const std::set<std::string>& keys,
                              std::map<std::string, bufferlist> *vals);
    int omap_set(const std::string& oid,
                 const std::map<std::string, bufferlist>& map);
    int omap_set_header(const std::string& oid,
                        const bufferlist& bl);
    int omap_clear(const std::string& oid);
    int omap_rm_keys(const std::string& oid,
                     const std::set<std::string>& keys);

    void snap_set_read(snap_t seq);
    int selfmanaged_snap_set_write_ctx(snap_t seq, std::vector<snap_t>& snaps);

    // Create a snapshot with a given name
    int snap_create(const char *snapname);

    // Look up a snapshot by name.
    // Returns 0 on success; error code otherwise
    int snap_lookup(const char *snapname, snap_t *snap);

    // Gets a timestamp for a snap
    int snap_get_stamp(snap_t snapid, time_t *t);

    // Gets the name of a snap
    int snap_get_name(snap_t snapid, std::string *s);

    // Remove a snapshot from this pool
    int snap_remove(const char *snapname);

    int snap_list(std::vector<snap_t> *snaps);

    int snap_rollback(const std::string& oid, const char *snapname);
    // Deprecated name kept for backward compatibility - same as snap_rollback()
    int rollback(const std::string& oid, const char *snapname);

    int selfmanaged_snap_create(uint64_t *snapid);

    int selfmanaged_snap_remove(uint64_t snapid);

    int selfmanaged_snap_rollback(const std::string& oid, uint64_t snapid);

    // Advisory locking on rados objects.
    int lock_exclusive(const std::string &oid, const std::string &name,
		       const std::string &cookie,
		       const std::string &description,
		       struct timeval * duration, uint8_t flags);

    int lock_shared(const std::string &oid, const std::string &name,
		    const std::string &cookie, const std::string &tag,
		    const std::string &description,
		    struct timeval * duration, uint8_t flags);

    int unlock(const std::string &oid, const std::string &name,
	       const std::string &cookie);

    int break_lock(const std::string &oid, const std::string &name,
		   const std::string &client, const std::string &cookie);

    int list_lockers(const std::string &oid, const std::string &name,
		     int *exclusive,
		     std::string *tag,
		     std::list<librados::locker_t> *lockers);


    /// Start enumerating objects for a pool
    ObjectIterator objects_begin();
    /// Start enumerating objects for a pool starting from a hash position
    ObjectIterator objects_begin(uint32_t start_hash_position);
    /// Iterator indicating the end of a pool
    const ObjectIterator& objects_end() const;

    /**
     * List available hit set objects
     *
     * @param uint32_t [in] hash position to query
     * @param c [in] completion
     * @param pls [out] list of available intervals
     */
    int hit_set_list(uint32_t hash, AioCompletion *c,
		     std::list< std::pair<time_t, time_t> > *pls);

    /**
     * Retrieve hit set for a given hash, and time
     *
     * @param uint32_t [in] hash position
     * @param c [in] completion
     * @param stamp [in] time interval that falls within the hit set's interval
     * @param pbl [out] buffer to store the result in
     */
    int hit_set_get(uint32_t hash, AioCompletion *c, time_t stamp,
		    bufferlist *pbl);

    uint64_t get_last_version();

    int aio_read(const std::string& oid, AioCompletion *c,
		 bufferlist *pbl, size_t len, uint64_t off);
    /**
     * Asynchronously read from an object at a particular snapshot
     *
     * This is the same as normal aio_read, except that it chooses
     * the snapshot to read from from its arguments instead of the
     * internal IoCtx state.
     *
     * The return value of the completion will be number of bytes read on
     * success, negative error code on failure.
     *
     * @param oid the name of the object to read from
     * @param c what to do when the read is complete
     * @param pbl where to store the results
     * @param len the number of bytes to read
     * @param off the offset to start reading from in the object
     * @param snapid the id of the snapshot to read from
     * @returns 0 on success, negative error code on failure
     */
    int aio_read(const std::string& oid, AioCompletion *c,
		 bufferlist *pbl, size_t len, uint64_t off, uint64_t snapid);
    int aio_sparse_read(const std::string& oid, AioCompletion *c,
			std::map<uint64_t,uint64_t> *m, bufferlist *data_bl,
			size_t len, uint64_t off);
    /**
     * Asynchronously read existing extents from an object at a
     * particular snapshot
     *
     * This is the same as normal aio_sparse_read, except that it chooses
     * the snapshot to read from from its arguments instead of the
     * internal IoCtx state.
     *
     * m will be filled in with a map of extents in the object,
     * mapping offsets to lengths (in bytes) within the range
     * requested. The data for all of the extents are stored
     * back-to-back in offset order in data_bl.
     *
     * @param oid the name of the object to read from
     * @param c what to do when the read is complete
     * @param m where to store the map of extents
     * @param data_bl where to store the data
     * @param len the number of bytes to read
     * @param off the offset to start reading from in the object
     * @param snapid the id of the snapshot to read from
     * @returns 0 on success, negative error code on failure
     */
    int aio_sparse_read(const std::string& oid, AioCompletion *c,
			std::map<uint64_t,uint64_t> *m, bufferlist *data_bl,
			size_t len, uint64_t off, uint64_t snapid);
    int aio_write(const std::string& oid, AioCompletion *c, const bufferlist& bl,
		  size_t len, uint64_t off);
    int aio_append(const std::string& oid, AioCompletion *c, const bufferlist& bl,
		  size_t len);
    int aio_write_full(const std::string& oid, AioCompletion *c, const bufferlist& bl);

    /**
     * Asychronously remove an object
     *
     * Queues the remove and returns.
     *
     * The return value of the completion will be 0 on success, negative
     * error code on failure.
     *
     * @param io the context to operate in
     * @param oid the name of the object
     * @param completion what to do when the remove is safe and complete
     * @returns 0 on success, -EROFS if the io context specifies a snap_seq
     * other than SNAP_HEAD
     */
    int aio_remove(const std::string& oid, AioCompletion *c);

    /**
     * Wait for all currently pending aio writes to be safe.
     *
     * @returns 0 on success, negative error code on failure
     */
    int aio_flush();

    /**
     * Schedule a callback for when all currently pending
     * aio writes are safe. This is a non-blocking version of
     * aio_flush().
     *
     * @param c what to do when the writes are safe
     * @returns 0 on success, negative error code on failure
     */
    int aio_flush_async(AioCompletion *c);

    int aio_stat(const std::string& oid, AioCompletion *c, uint64_t *psize, time_t *pmtime);

    int aio_exec(const std::string& oid, AioCompletion *c, const char *cls, const char *method,
	         bufferlist& inbl, bufferlist *outbl);

    // compound object operations
    int operate(const std::string& oid, ObjectWriteOperation *op);
    int operate(const std::string& oid, ObjectReadOperation *op, bufferlist *pbl);
    int aio_operate(const std::string& oid, AioCompletion *c, ObjectWriteOperation *op);
    int aio_operate(const std::string& oid, AioCompletion *c, ObjectWriteOperation *op, int flags);
    /**
     * Schedule an async write operation with explicit snapshot parameters
     *
     * This is the same as the first aio_operate(), except that it
     * gets the snapshot context from its arguments instead of the
     * IoCtx internal state.
     *
     * @param oid the object to operate on
     * @param c what to do when the operation is complete and safe
     * @param op which operations to perform
     * @param seq latest selfmanaged snapshot sequence number for this object
     * @param snaps currently existing selfmanaged snapshot ids for this object
     * @returns 0 on success, negative error code on failure
     */
    int aio_operate(const std::string& oid, AioCompletion *c,
		    ObjectWriteOperation *op, snap_t seq,
		    std::vector<snap_t>& snaps);
    int aio_operate(const std::string& oid, AioCompletion *c,
		    ObjectReadOperation *op, bufferlist *pbl);

    int aio_operate(const std::string& oid, AioCompletion *c,
		    ObjectReadOperation *op, snap_t snapid, int flags,
		    bufferlist *pbl)
      __attribute__ ((deprecated));

    int aio_operate(const std::string& oid, AioCompletion *c,
		    ObjectReadOperation *op, int flags,
		    bufferlist *pbl);

    // watch/notify
    int watch(const std::string& o, uint64_t ver, uint64_t *handle,
	      librados::WatchCtx *ctx);
    int unwatch(const std::string& o, uint64_t handle);
    int notify(const std::string& o, uint64_t ver, bufferlist& bl);
    int list_watchers(const std::string& o, std::list<obj_watch_t> *out_watchers);
    int list_snaps(const std::string& o, snap_set_t *out_snaps);
    void set_notify_timeout(uint32_t timeout);

    /**
     * Set allocation hint for an object
     *
     * This is an advisory operation, it will always succeed (as if it
     * was submitted with a OP_FAILOK flag set) and is not guaranteed
     * to do anything on the backend.
     *
     * @param o the name of the object
     * @param expected_object_size expected size of the object, in bytes
     * @param expected_write_size expected size of writes to the object, in bytes
     * @returns 0 on success, negative error code on failure
     */
    int set_alloc_hint(const std::string& o,
                       uint64_t expected_object_size,
                       uint64_t expected_write_size);

    // assert version for next sync operations
    void set_assert_version(uint64_t ver);
    void set_assert_src_version(const std::string& o, uint64_t ver);

    const std::string& get_pool_name() const;

    void locator_set_key(const std::string& key);
    void set_namespace(const std::string& nspace);

    int64_t get_id();

    uint32_t get_object_hash_position(const std::string& oid);
    uint32_t get_object_pg_hash_position(const std::string& oid);

    config_t cct();

  private:
    /* You can only get IoCtx instances from Rados */
    IoCtx(IoCtxImpl *io_ctx_impl_);

    friend class Rados; // Only Rados can use our private constructor to create IoCtxes.
    friend class ObjectWriteOperation;  // copy_from needs to see our IoCtxImpl

    IoCtxImpl *io_ctx_impl;
  };

  class Rados
  {
  public:
    static void version(int *major, int *minor, int *extra);

    Rados();
    explicit Rados(IoCtx& ioctx);
    ~Rados();

    int init(const char * const id);
    int init2(const char * const name, const char * const clustername,
	      uint64_t flags);
    int init_with_context(config_t cct_);
    config_t cct();
    int connect();
    void shutdown();
    int conf_read_file(const char * const path) const;
    int conf_parse_argv(int argc, const char ** argv) const;
    int conf_parse_argv_remainder(int argc, const char ** argv,
				  const char ** remargv) const;
    int conf_parse_env(const char *env) const;
    int conf_set(const char *option, const char *value);
    int conf_get(const char *option, std::string &val);

    int pool_create(const char *name);
    int pool_create(const char *name, uint64_t auid);
    int pool_create(const char *name, uint64_t auid, uint8_t crush_rule);
    int pool_create_async(const char *name, PoolAsyncCompletion *c);
    int pool_create_async(const char *name, uint64_t auid, PoolAsyncCompletion *c);
    int pool_create_async(const char *name, uint64_t auid, uint8_t crush_rule, PoolAsyncCompletion *c);
    int pool_delete(const char *name);
    int pool_delete_async(const char *name, PoolAsyncCompletion *c);
    int64_t pool_lookup(const char *name);
    int pool_reverse_lookup(int64_t id, std::string *name);

    uint64_t get_instance_id();

    int mon_command(std::string cmd, const bufferlist& inbl,
		    bufferlist *outbl, std::string *outs);

    int ioctx_create(const char *name, IoCtx &pioctx);

    // Features useful for test cases
    void test_blacklist_self(bool set);

    /* listing objects */
    int pool_list(std::list<std::string>& v);
    int get_pool_stats(std::list<std::string>& v,
		       std::map<std::string, stats_map>& stats);
    int get_pool_stats(std::list<std::string>& v,
                       std::string& category,
		       std::map<std::string, stats_map>& stats);
    int cluster_stat(cluster_stat_t& result);
    int cluster_fsid(std::string *fsid);

    /// get/wait for the most recent osdmap
    int wait_for_latest_osdmap();

    /*
     * pool aio
     *
     * It is up to the caller to release the completion handler, even if the pool_create_async()
     * and/or pool_delete_async() fails and does not send the async request
     */
    static PoolAsyncCompletion *pool_async_create_completion();

   // -- aio --
    static AioCompletion *aio_create_completion();
    static AioCompletion *aio_create_completion(void *cb_arg, callback_t cb_complete,
						callback_t cb_safe);

    friend std::ostream& operator<<(std::ostream &oss, const Rados& r);
  private:
    // We don't allow assignment or copying
    Rados(const Rados& rhs);
    const Rados& operator=(const Rados& rhs);
    RadosClient *client;
  };
}

#endif