interface for transaction log management added to handlerton

iterators creation interface added to handlerton


sql/ha_berkeley.cc:
  added new methods
sql/ha_federated.cc:
  added new methods
sql/ha_heap.cc:
  added new methods
sql/ha_innodb.cc:
  added new methods
sql/ha_myisam.cc:
  added new methods
sql/ha_myisammrg.cc:
  added new methods
sql/ha_ndbcluster.cc:
  added new methods
sql/ha_partition.cc:
  added new methods
sql/handler.cc:
  added new methods
  spelling fixed
  examples of functions for new interface added
sql/handler.h:
  transaction logs management interface added
  general iterator creatioin interface added
sql/log.cc:
  added new methods
storage/archive/ha_archive.cc:
  added new methods
storage/blackhole/ha_blackhole.cc:
  added new methods
storage/csv/ha_tina.cc:
  added new methods
storage/example/ha_example.cc:
  added new methods

1 files changed, 83 insertions, 0 deletions

diff --git a/sql/handler.h b/sql/handler.h
index afee6bb9f8d..4bc4f8b0c68 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -461,6 +461,72 @@ typedef bool (stat_print_fn)(THD *thd, const char *type, uint type_len,
                              const char *status, uint status_len);
 enum ha_stat_type { HA_ENGINE_STATUS, HA_ENGINE_LOGS, HA_ENGINE_MUTEX };
 
+/* Transaction log maintains type definitions */
+enum log_status
+{
+  HA_LOG_STATUS_FREE= 0,      /* log is free and can be deleted */
+  HA_LOG_STATUS_INUSE= 1,     /* log can't be deleted because it is in use */
+  HA_LOG_STATUS_NOSUCHLOG= 2  /* no such log (can't be returned by
+                                the log iterator status) */
+};
+/*
+  Function for signaling that the log file changed its state from
+  LOG_STATUS_INUSE to LOG_STATUS_FREE
+
+  Now it do nothing, will be implemented as part of new transaction
+  log management for engines.
+  TODO: implement the function.
+*/
+void signal_log_not_needed(struct handlerton, char *log_file);
+/*
+  Data of transaction log iterator.
+*/
+struct handler_log_file_data {
+  LEX_STRING filename;
+  enum log_status status;
+};
+
+
+enum handler_iterator_type
+{
+  /* request of transaction log iterator */
+  HA_TRANSACTLOG_ITERATOR= 1
+};
+enum handler_create_iterator_result
+{
+  HA_ITERATOR_OK,          /* iterator created */
+  HA_ITERATOR_UNSUPPORTED, /* such type of iterator is not supported */
+  HA_ITERATOR_ERROR        /* error during iterator creation */
+};
+
+/*
+  Iterator structure. Can be used by handler/handlerton for different purposes.
+
+  Iterator should be created in the way to point "before" the first object
+  it iterate, so next() call move it to the first object or return !=0 if
+  there is nothing to iterate through.
+*/
+struct handler_iterator {
+  /*
+    Moves iterator to next record and return 0 or return !=0
+    if there is no records.
+    iterator_object will be filled by this function if next() returns 0.
+    Content of the iterator_object depend on iterator type.
+  */
+  int (*next)(struct handler_iterator *, void *iterator_object);
+  /*
+    Free resources allocated by iterator, after this call iterator
+    is not usable.
+  */
+  void (*destroy)(struct handler_iterator *);
+  /*
+    Pointer to buffer for the iterator to use.
+    Should be allocated by function which created the iterator and
+    destroied by freed by above "destroy" call
+  */
+  void *buffer;
+};
+
 /*
   handlerton is a singleton structure - one instance per storage engine -
   to provide access to storage engine functionality that works on the
@@ -585,6 +651,23 @@ struct handlerton
                             const char *query, uint query_length,
                             const char *db, const char *table_name);
    int (*release_temporary_latches)(THD *thd);
+
+   /*
+     Get log status.
+     If log_status is null then the handler do not support transaction
+     log information (i.e. log iterator can't be created).
+     (see example of implementation in handler.cc, TRANS_LOG_MGM_EXAMPLE_CODE)
+
+   */
+   enum log_status (*get_log_status)(char *log);
+
+   /*
+     Iterators creator.
+     Presence of the pointer should be checked before using
+   */
+   enum handler_create_iterator_result
+     (*create_iterator)(enum handler_iterator_type type,
+                        struct handler_iterator *fill_this_in);
 };
 
 extern const handlerton default_hton;