WL#1012: All changes as one single changeset.

This includes both code and test cases.

1 files changed, 109 insertions, 0 deletions

diff --git a/sql/rpl_tblmap.h b/sql/rpl_tblmap.h
new file mode 100644
index 00000000000..cfc2d7c2c6c
--- /dev/null
+++ b/sql/rpl_tblmap.h
@@ -0,0 +1,109 @@
+/* Copyright (C) 2005 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#ifndef TABLE_MAPPING_H
+#define TABLE_MAPPING_H
+
+/* Forward declarations */
+struct st_table;
+typedef st_table TABLE;
+
+/*
+  CLASS table_mapping
+
+  RESPONSIBILITIES
+    The table mapping is used to map table id's to table pointers
+
+  COLLABORATION
+    RELAY_LOG    For mapping table id:s to tables when receiving events.
+ */
+
+/*
+  Guilhem to Mats:
+  in the table_mapping class, the memory is allocated and never freed (until
+  destruction). So this is a good candidate for allocating inside a MEM_ROOT:
+  it gives the efficient allocation in chunks (like in expand()). So I have
+  introduced a MEM_ROOT.
+
+  Note that inheriting from Sql_alloc had no effect: it has effects only when
+  "ptr= new table_mapping" is called, and this is never called. And it would
+  then allocate from thd->mem_root which is a highly volatile object (reset
+  from example after executing each query, see dispatch_command(), it has a
+  free_root() at end); as the table_mapping object is supposed to live longer
+  than a query, it was dangerous.
+  A dedicated MEM_ROOT needs to be used, see below.
+*/
+
+class table_mapping {
+
+private:
+  MEM_ROOT m_mem_root;
+
+public:
+
+  enum {
+    NO_TABLE = ULONG_MAX
+  };
+
+  enum enum_error {
+      ERR_NO_ERROR = 0,
+      ERR_LIMIT_EXCEEDED,
+      ERR_MEMORY_ALLOCATION
+  };
+
+  table_mapping();
+  ~table_mapping();
+
+  TABLE* get_table(ulong table_id);
+
+  int       set_table(ulong table_id, TABLE* table);
+  int       remove_table(ulong table_id);
+  void      clear_tables();
+  ulong     count() const { return m_table_ids.records; }
+
+private:
+  /*
+    This is a POD (Plain Old Data).  Keep it that way (we apply offsetof() to
+    it, which only works for PODs)
+  */
+  struct entry { 
+    ulong table_id;
+    union {
+      TABLE *table;
+      entry *next;
+    };
+  };
+
+  entry *find_entry(ulong table_id)
+  {
+    return (entry *)hash_search(&m_table_ids,
+				(byte*)&table_id,
+				sizeof(table_id));
+  }
+  int expand();
+
+  /*
+    Head of the list of free entries; "free" in the sense that it's an
+    allocated entry free for use, NOT in the sense that it's freed
+    memory.
+  */
+  entry *m_free;
+
+  /* Correspondance between an id (a number) and a TABLE object */
+  HASH m_table_ids;
+};
+
+#endif