prohibit opening Query cache for SP cursors (BUG#9715)

mysql-test/r/query_cache.result:
  testing cursors in SP with QC
  testing suspicious but working using selects in function with QC
mysql-test/t/query_cache.test:
  testing cursors in SP with QC
  testing suspicious but working using selects in function with QC
sql/sp_head.h:
  method for prohibiting of QC using SP query
sql/sp_rcontext.cc:
  prohibit opening Query cache for SP cursors
sql/sp_rcontext.h:
  constructor moved to .cc file to be able to use methods from lex_keeper

mysql-test/t/query_cache.test

@@ -756,4 +756,36 @@ flush query cache;
 
 drop table t1, t2;
 
+#
+# SP cursors and selects with query cache (BUG#9715)
+#
+create table t1 (a int);
+insert into t1 values (1),(2);
+
+delimiter //;
+CREATE PROCEDURE `p1`()
+begin
+Declare c1 cursor for select a from t1;
+open c1;
+select * from t1;
+end//
+call p1()//
+drop procedure p1;
+
+create function f1() returns int
+begin
+Declare var1 int;
+select max(a) from t1 into var1;
+return var1;
+end//
+create procedure `p1`()
+begin
+ select a, f1() from t1;
+end//
+call p1()//
+drop procedure p1//
+
+drop table t1//
+delimiter ;//
+
 set GLOBAL query_cache_size=0;

sql/sp_head.h

@@ -377,6 +377,10 @@ class sp_lex_keeper
     return (uint)m_lex->sql_command;
   }
 
+  void disable_query_cache()
+  {
+    m_lex->safe_to_cache_query= 0;
+  }
 private:
 
   LEX *m_lex;

sql/sp_rcontext.cc

@@ -169,6 +169,17 @@ sp_rcontext::pop_cursors(uint count)
  *
  */
 
+sp_cursor::sp_cursor(sp_lex_keeper *lex_keeper)
+  :m_lex_keeper(lex_keeper), m_prot(NULL), m_isopen(0), m_current_row(NULL)
+{
+  /*
+    currsor can't be stored in QC, so we should prevent opening QC for
+    try to write results which are absent.
+  */
+  lex_keeper->disable_query_cache();
+}
+
+
 /*
   pre_open cursor
 

sql/sp_rcontext.h

@@ -203,11 +203,7 @@ class sp_cursor : public Sql_alloc
 {
 public:
 
-  sp_cursor(sp_lex_keeper *lex_keeper)
-    : m_lex_keeper(lex_keeper), m_prot(NULL), m_isopen(0), m_current_row(NULL)
-  {
-    /* Empty */
-  }
+  sp_cursor(sp_lex_keeper *lex_keeper);
 
   virtual ~sp_cursor()
   {