bzr commit into mysql-5.1 branch (holyfoot:2655) Bug#41481

[Alexey Botchkov]

#At file:///home/hf/work/mysql_common/wrk41481/

 2655 Alexey Botchkov	2008-12-24
      Bug#41481 Buffer function never returns, cpu 100%, system locks up 
          some cases were inproperly handled in the 'slicescan' alorithm
      
      modified:
        sql/gcalc_slicescan.cc
        sql/item_geofunc.cc
modified:
  sql/gcalc_slicescan.cc
  sql/item_geofunc.cc

=== modified file 'sql/gcalc_slicescan.cc'
--- a/sql/gcalc_slicescan.cc	2007-11-22 16:17:17 +0000
+++ b/sql/gcalc_slicescan.cc	2008-12-24 16:54:44 +0000
@@ -538,7 +538,7 @@ int gcalc_scan_iterator::handle_intersec
 
   m_sav_slice= m_slice1;
   m_sav_y= m_y1;
-  m_slice1= new_slice(m_slice0);
+  m_slice1= new_slice(m_sav_slice);
   
   m_cur_intersection= m_intersections;
   m_pre_intersection_hook= NULL;
@@ -632,7 +632,7 @@ redo_loop:
       if (next_s0->thread != m_cur_intersection->thread_b)
       {
 	/* It's really rare case - sometimes happen when
-	   there's two intersection with the same Y
+	   there's two intersections with the same Y
 	   Move suitable one to the beginning of the list
 	*/
 	pop_suitable_intersection();
@@ -661,6 +661,12 @@ redo_loop:
     psp1= (point **)&sp1->next;
   }
 
+  if (*psp1)
+  {
+    free_list(*psp1);
+    *psp1= NULL;
+  }
+
   return 0;
 }
 

=== modified file 'sql/item_geofunc.cc'
--- a/sql/item_geofunc.cc	2008-01-28 15:32:34 +0000
+++ b/sql/item_geofunc.cc	2008-12-24 16:54:44 +0000
@@ -698,7 +698,6 @@ String *Item_func_spatial_operation::val
   String *res2= args[1]->val_str(&tmp_value2);
   Geometry_buffer buffer1, buffer2;
   Geometry *g1, *g2;
-  int result;
   uint32 srid= 0;
 
   if (func.reserve_op_buffer(1))
@@ -1029,7 +1028,7 @@ int Item_func_buffer::add_line_buffer(gc
     return 0;
   }
 
-  if (!p_next->left) /* Line consists of two points */
+  if (p_next->left == p1) /* Line consists of two points */
   {
     if (add_edge_buffer(p_cur, p_next, p_next->left, d, true, true))
       return 1;
@@ -1044,7 +1043,7 @@ int Item_func_buffer::add_line_buffer(gc
 
   p_cur= p_next;
   p_next= p_next->left;
-  while (p_next->left)
+  while (p_next->left != p_cur)
   {
     if (add_edge_buffer(p_cur, p_next, p_next->left, d, false, false))
       return 1;