Table definition cache, part 2

The table opening process now works the following way:
- Create common TABLE_SHARE object
- Read the .frm file and unpack it into the TABLE_SHARE object
- Create a TABLE object based on the information in the TABLE_SHARE
  object and open a handler to the table object

Other noteworthy changes:
- In TABLE_SHARE the most common strings are now LEX_STRING's
- Better error message when table is not found
- Variable table_cache is now renamed 'table_open_cache'
- New variable 'table_definition_cache' that is the number of table defintions that will be cached
- strxnmov() calls are now fixed to avoid overflows
- strxnmov() will now always add one end \0 to result
- engine objects are now created with a TABLE_SHARE object instead of a TABLE object.
- After creating a field object one must call field->init(table) before using it

- For a busy system this change will give you:
 - Less memory usage for table object
 - Faster opening of tables (if it's has been in use or is in table definition cache)
 - Allow you to cache many table definitions objects
 - Faster drop of table

1 files changed, 19 insertions, 7 deletions

diff --git a/mysys/mf_tempdir.c b/mysys/mf_tempdir.c
index 4d244aa7d74..f7c6fbb29a6 100644
--- a/mysys/mf_tempdir.c
+++ b/mysys/mf_tempdir.c
@@ -28,9 +28,12 @@ my_bool init_tmpdir(MY_TMPDIR *tmpdir, const char *pathlist)
   char *end, *copy;
   char buff[FN_REFLEN];
   DYNAMIC_ARRAY t_arr;
+  DBUG_ENTER("init_tmpdir");
+  DBUG_PRINT("enter", ("pathlist: %s", pathlist ? pathlist : "NULL"));
+
   pthread_mutex_init(&tmpdir->mutex, MY_MUTEX_INIT_FAST);
   if (my_init_dynamic_array(&t_arr, sizeof(char*), 1, 5))
-    return TRUE;
+    goto err;
   if (!pathlist || !pathlist[0])
   {
     /* Get default temporary directory */
@@ -46,12 +49,13 @@ my_bool init_tmpdir(MY_TMPDIR *tmpdir, const char *pathlist)
   }
   do
   {
+    uint length;
     end=strcend(pathlist, DELIM);
-    convert_dirname(buff, pathlist, end);
-    if (!(copy=my_strdup(buff, MYF(MY_WME))))
-      return TRUE;
-    if (insert_dynamic(&t_arr, (gptr)&copy))
-      return TRUE;
+    strmake(buff, pathlist, (uint) (end-pathlist));
+    length= cleanup_dirname(buff, buff);
+    if (!(copy= my_strdup_with_length(buff, length, MYF(MY_WME))) ||
+        insert_dynamic(&t_arr, (gptr) &copy))
+      DBUG_RETURN(TRUE)
     pathlist=end+1;
   }
   while (*end);
@@ -59,12 +63,20 @@ my_bool init_tmpdir(MY_TMPDIR *tmpdir, const char *pathlist)
   tmpdir->list=(char **)t_arr.buffer;
   tmpdir->max=t_arr.elements-1;
   tmpdir->cur=0;
-  return FALSE;
+  DBUG_RETURN(FALSE);
+
+err:
+  delete_dynamic(&t_arr);                       /* Safe to free */
+  pthread_mutex_destroy(&tmpdir->mutex);
+  DBUG_RETURN(TRUE);
 }
 
+
 char *my_tmpdir(MY_TMPDIR *tmpdir)
 {
   char *dir;
+  if (!tmpdir->max)
+    return tmpdir->list[0];
   pthread_mutex_lock(&tmpdir->mutex);
   dir=tmpdir->list[tmpdir->cur];
   tmpdir->cur= (tmpdir->cur == tmpdir->max) ? 0 : tmpdir->cur+1;