/*
 * These are arguments to the load_key_blob method, called
 * when a checkpoint is loaded, either at startup or when
 * a new checkpoint is picked up on a follower.
 *
 * Fields in this structure are set by WiredTiger and should
 * not be changed by the key management extension.
 */
struct WT_KEY_MANAGEMENT_LOAD_ARGS {
    void *blob_data;
    void size_t blob_size;
};

/*
 * These are arguments to the get_key_blob and get_key_complete
 * methods, which are called when WiredTiger is writing a
 * checkpoint.
 *
 * Fields in this structure, except for returned_lsn,
 * are set by the key management extension, and are
 * not changed by WiredTiger. If has_changes is true,
 * blob_data and blob_size must be set by the extension,
 * and define the data that is written by WiredTiger. In
 * that case, when the blob write has completed,
 * get_complete_key is called. If has_changes is false,
 * no write is done by WiredTiger, and get_key_complete
 * is not called as a result.
 */
struct WT_KEY_MANAGEMENT_GET_ARGS {
    void *blob_data;     /* 
    void size_t blob_size;
    boolean has_changes; /* Blob has changed since last call */
    uint64_t returned_lsn; /* Set by WiredTiger for get_key_complete */
};

/*
 * The interface to the key management module, loaded at startup.
 * Each function is a callback made by WiredTiger.
 */
struct WT_KEY_MANAGEMENT {
    /* Called by WiredTiger when a checkpoint is loaded. */
    void load_key_blob(WT_KEY_MANAGEMENT *km, 
                       WT_KEY_MANAGEMENT_LOAD_ARGS *args);

    /* Called by WiredTiger when storing a checkpoint. */
    void get_key_blob(WT_KEY_MANAGEMENT *km,
                       WT_KEY_MANAGEMENT_GET_ARGS *args);

    /* 
     * Called by WiredTiger after the get_key_blob call,
     * when the key blob has been persisted.
     */
    void get_key_complete(WT_KEY_MANAGEMENT *km,
                      WT_KEY_MANAGEMENT_GET_ARGS *args);
};