1 files changed, 125 insertions, 0 deletions
diff --git a/sql/sql_plist.h b/sql/sql_plist.h
new file mode 100644
index 00000000000..af2ed227ea1
--- /dev/null
+++ b/sql/sql_plist.h
@@ -0,0 +1,125 @@
+#ifndef SQL_PLIST_H
+#define SQL_PLIST_H
+/* Copyright (C) 2008 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; version 2 of the License.
+
+   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 */
+
+
+#include <my_global.h>
+
+template <typename T, typename B> class I_P_List_iterator;
+
+
+/**
+   Intrusive parameterized list.
+
+   Unlike I_List does not require its elements to be descendant of ilink
+   class and therefore allows them to participate in several such lists
+   simultaneously.
+
+   Unlike List is doubly-linked list and thus supports efficient deletion
+   of element without iterator.
+
+   @param T  Type of elements which will belong to list.
+   @param B  Class which via its methods specifies which members
+             of T should be used for participating in this list.
+             Here is typical layout of such class:
+
+             struct B
+             {
+               static inline T **next_ptr(T *el)
+               {
+                 return &el->next;
+               }
+               static inline T ***prev_ptr(T *el)
+               {
+                 return &el->prev;
+               }
+             };
+*/
+
+template <typename T, typename B>
+class I_P_List
+{
+  T *first;
+
+  /*
+    Do not prohibit copying of I_P_List object to simplify their usage in
+    backup/restore scenarios. Note that performing any operations on such
+    is a bad idea.
+  */
+public:
+  I_P_List() : first(NULL) { };
+  inline void empty()      { first= NULL; }
+  inline bool is_empty()   { return (first == NULL); }
+  inline void push_front(T* a)
+  {
+    *B::next_ptr(a)= first;
+    if (first)
+      *B::prev_ptr(first)= B::next_ptr(a);
+    first= a;
+    *B::prev_ptr(a)= &first;
+  }
+  inline void remove(T *a)
+  {
+    T *next= *B::next_ptr(a);
+    if (next)
+      *B::prev_ptr(next)= *B::prev_ptr(a);
+    **B::prev_ptr(a)= next;
+  }
+  inline T* head() { return first; }
+  void swap(I_P_List<T,B> &rhs)
+  {
+    swap_variables(T *, first, rhs.first);
+    if (first)
+      *B::prev_ptr(first)= &first;
+    if (rhs.first)
+      *B::prev_ptr(rhs.first)= &rhs.first;
+  }
+#ifndef _lint
+  friend class I_P_List_iterator<T, B>;
+#endif
+};
+
+
+/**
+   Iterator for I_P_List.
+*/
+
+template <typename T, typename B>
+class I_P_List_iterator
+{
+  I_P_List<T, B> *list;
+  T *current;
+public:
+  I_P_List_iterator(I_P_List<T, B> &a) : list(&a), current(a.first) {}
+  inline void init(I_P_List<T, B> &a)
+  {
+    list= &a;
+    current= a.first;
+  }
+  inline T* operator++(int)
+  {
+    T *result= current;
+    if (result)
+      current= *B::next_ptr(current);
+    return result;
+  }
+  inline void rewind()
+  {
+    current= list->first;
+  }
+};
+
+#endif