Manual merge for WL#1622 code, will need fixes

sql/item.cc:
  Auto merged
sql/item.h:
  Auto merged
sql/mysqld.cc:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_prepare.cc:
  Manual merge, will need fixes

mysql-test/r/ps.result

+drop table if exists t1,t2;
+create table t1
+(
+a int primary key,
+b char(10),
+);
+insert into t1 values (1,'one');
+insert into t1 values (2,'two');
+insert into t1 values (3,'three');
+insert into t1 values (4,'four');
+set @a=2;
+prepare stmt1 from 'select * from t1 where a <= ?';
+execute stmt1 using @a;
+a	b
+1	one
+2	two
+set @a=3;
+execute stmt1 using @a;
+a	b
+1	one
+2	two
+3	three
+deallocate prepare no_such_statement;
+ERROR HY000: Undefined prepared statement
+execute stmt1;
+ERROR HY000: Wrong arguments to mysql_execute
+prepare stmt2 from 'prepare nested_stmt from "select 1"';
+ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near '"select 1"' at line 1
+prepare stmt2 from 'execute stmt1';
+ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near 'stmt1' at line 1
+prepare stmt2 from 'deallocate prepare z';
+ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near 'z' at line 1
+prepare stmt3 from 'insert into t1 values (?,?)';
+set @arg1=5, @arg2='five';
+execute stmt3 using @arg1, @arg2;
+select * from t1 where a>3;
+a	b
+4	four
+5	five
+prepare stmt4 from 'update t1 set a=? where b=?';
+set @arg1=55, @arg2='five';
+execute stmt4 using @arg1, @arg2;
+select * from t1 where a>3;
+a	b
+4	four
+55	five
+prepare stmt4 from 'create table t2 (a int)';
+execute stmt4;
+prepare stmt4 from 'drop table t2';
+execute stmt4;
+execute stmt4;
+ERROR 42S02: Unknown table 't2'
+prepare stmt5 from 'select ? + a from t1';
+set @a=1;
+execute stmt5 using @a;
+? + a
+2
+3
+4
+5
+56
+execute stmt5 using @no_such_var;
+? + a
+NULL
+NULL
+NULL
+NULL
+NULL
+set @nullvar=1;
+set @nullvar=NULL;
+execute stmt5 using @nullvar;
+? + a
+NULL
+NULL
+NULL
+NULL
+NULL
+set @nullvar2=NULL;
+execute stmt5 using @nullvar2;
+? + a
+NULL
+NULL
+NULL
+NULL
+NULL
+prepare stmt6 from 'select 1; select2';
+ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near '; select2' at line 1
+prepare stmt6 from 'insert into t1 values (5,"five"); select2';
+ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near '; select2' at line 1
+explain prepare stmt6 from 'insert into t1 values (5,"five"); select2';
+ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near 'from 'insert into t1 values (5,"five"); select2'' at line 1
+drop table t1;

mysql-test/t/ps.test

+#
+# SQL Syntax for Prepared Statements test
+#
+--disable_warnings
+drop table if exists t1,t2;
+--enable_warnings
+
+create table t1
+(
+  a int primary key,
+  b char(10),
+);
+insert into t1 values (1,'one');
+insert into t1 values (2,'two');
+insert into t1 values (3,'three');
+insert into t1 values (4,'four');
+
+# basic functionality
+set @a=2;
+prepare stmt1 from 'select * from t1 where a <= ?';
+execute stmt1 using @a;
+set @a=3;
+execute stmt1 using @a;
+
+# non-existant statement
+--error 1243
+deallocate prepare no_such_statement;
+
+--error 1210
+execute stmt1;
+
+# Nesting ps commands is not allowed: 
+--error 1064
+prepare stmt2 from 'prepare nested_stmt from "select 1"';
+
+--error 1064
+prepare stmt2 from 'execute stmt1';
+
+--error 1064
+prepare stmt2 from 'deallocate prepare z';
+
+# PS insert 
+prepare stmt3 from 'insert into t1 values (?,?)';
+set @arg1=5, @arg2='five';
+execute stmt3 using @arg1, @arg2;
+select * from t1 where a>3;
+
+# PS update 
+prepare stmt4 from 'update t1 set a=? where b=?';
+set @arg1=55, @arg2='five';
+execute stmt4 using @arg1, @arg2;
+select * from t1 where a>3;
+
+# PS create/delete
+prepare stmt4 from 'create table t2 (a int)';
+execute stmt4;
+prepare stmt4 from 'drop table t2';
+execute stmt4;
+
+# Do something that will cause error
+--error 1051
+execute stmt4;
+
+# placeholders in result field names.
+prepare stmt5 from 'select ? + a from t1';
+set @a=1;
+execute stmt5 using @a;
+
+execute stmt5 using @no_such_var;
+
+set @nullvar=1;
+set @nullvar=NULL;
+execute stmt5 using @nullvar;
+
+set @nullvar2=NULL;
+execute stmt5 using @nullvar2;
+
+# Check that multiple SQL statements are disabled inside PREPARE
+--error 1064
+prepare stmt6 from 'select 1; select2';
+
+--error 1064
+prepare stmt6 from 'insert into t1 values (5,"five"); select2';
+
+# This shouldn't parse
+--error 1064
+explain prepare stmt6 from 'insert into t1 values (5,"five"); select2';
+
+drop table t1;
+

sql/item.cc

@@ -644,10 +644,10 @@ void Item_param::set_double(double value)
 }
 
 
-void Item_param::set_value(const char *str, uint length)
+void Item_param::set_value(const char *str, uint length, CHARSET_INFO *ci)
 {
   DBUG_ENTER("Item_param::set_value");
-  str_value.copy(str,length,default_charset());
+  str_value.copy(str,length,ci);
   item_type= STRING_ITEM;
   value_is_set= 1;
   maybe_null= 0;
@@ -655,6 +655,11 @@ void Item_param::set_value(const char *str, uint length)
   DBUG_VOID_RETURN;
 }
 
+void Item_param::set_value(const char *str, uint length)
+{
+  set_value(str, length, default_charset());
+}
+
 
 void Item_param::set_time(TIME *tm, timestamp_type type)
 { 
@@ -1528,7 +1533,7 @@ bool Item::send(Protocol *protocol, String *buffer)
   }
   case MYSQL_TYPE_TINY:
   {
-    longlong nr;
+    longlong nr;  
     nr= val_int();
     if (!null_value)
       result= protocol->store_tiny(nr);

sql/item.h

@@ -413,6 +413,7 @@ public:
   void set_int(longlong i);
   void set_double(double i);
   void set_value(const char *str, uint length);
+  void set_value(const char *str, uint length, CHARSET_INFO *ci);
   void set_long_str(const char *str, ulong length);
   void set_long_binary(const char *str, ulong length);
   void set_longdata(const char *str, ulong length);

sql/lex.h

@@ -133,6 +133,7 @@ static SYMBOL symbols[] = {
   { "DAY_MICROSECOND",	SYM(DAY_MICROSECOND_SYM)},
   { "DAY_MINUTE",	SYM(DAY_MINUTE_SYM)},
   { "DAY_SECOND",	SYM(DAY_SECOND_SYM)},
+  { "DEALLOCATE",       SYM(DEALLOCATE_SYM)},     
   { "DEC",		SYM(DECIMAL_SYM)},
   { "DECIMAL",		SYM(DECIMAL_SYM)},
   { "DEFAULT",		SYM(DEFAULT)},
@@ -324,6 +325,7 @@ static SYMBOL symbols[] = {
   { "POINT",		SYM(POINT_SYM)},
   { "POLYGON",		SYM(POLYGON)},
   { "PRECISION",	SYM(PRECISION)},
+  { "PREPARE",          SYM(PREPARE_SYM)},
   { "PREV",		SYM(PREV_SYM)},
   { "PRIMARY",		SYM(PRIMARY_SYM)},
   { "PRIVILEGES",	SYM(PRIVILEGES)},

sql/mysql_priv.h

@@ -634,8 +634,10 @@ int mysqld_show_column_types(THD *thd);
 int mysqld_help (THD *thd, const char *text);
 
 /* sql_prepare.cc */
-void mysql_stmt_prepare(THD *thd, char *packet, uint packet_length);
+int mysql_stmt_prepare(THD *thd, char *packet, uint packet_length, 
+                       LEX_STRING *name=NULL);
 void mysql_stmt_execute(THD *thd, char *packet, uint packet_length);
+void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name);
 void mysql_stmt_free(THD *thd, char *packet);
 void mysql_stmt_reset(THD *thd, char *packet);
 void mysql_stmt_get_longdata(THD *thd, char *pos, ulong packet_length);

sql/mysqld.cc

@@ -4822,6 +4822,9 @@ struct show_var_st status_vars[]= {
   {"Com_unlock_tables",	       (char*) (com_stat+(uint) SQLCOM_UNLOCK_TABLES),SHOW_LONG},
   {"Com_update",	       (char*) (com_stat+(uint) SQLCOM_UPDATE),SHOW_LONG},
   {"Com_update_multi",	       (char*) (com_stat+(uint) SQLCOM_UPDATE_MULTI),SHOW_LONG},
+  {"Com_prepare_sql",          (char*) (com_stat+(uint) SQLCOM_PREPARE), SHOW_LONG}, 
+  {"Com_execute_sql",          (char*) (com_stat+(uint) SQLCOM_EXECUTE), SHOW_LONG},
+  {"Com_dealloc_sql",          (char*) (com_stat+(uint) SQLCOM_DEALLOCATE_PREPARE), SHOW_LONG},
   {"Connections",              (char*) &thread_id,              SHOW_LONG_CONST},
   {"Created_tmp_disk_tables",  (char*) &created_tmp_disk_tables,SHOW_LONG},
   {"Created_tmp_files",	       (char*) &my_tmp_file_created,	SHOW_LONG},

sql/sql_class.cc

@@ -78,7 +78,6 @@ extern "C" void free_user_var(user_var_entry *entry)
   my_free((char*) entry,MYF(0));
 }
 
-
 /****************************************************************************
 ** Thread specific functions
 ****************************************************************************/
@@ -160,7 +159,7 @@ THD::THD():user_time(0), current_statement(0), is_fatal_error(0),
 			  16);
   else
     bzero((char*) &user_var_events, sizeof(user_var_events));
-
+  
   /* Protocol */
   protocol= &protocol_simple;			// Default protocol
   protocol_simple.init(this);
@@ -1199,6 +1198,7 @@ Statement::Statement(THD *thd)
   query_length(0),
   free_list(0)
 {
+  name.str= NULL;
   init_sql_alloc(&mem_root,
                  thd->variables.query_alloc_block_size,
                  thd->variables.query_prealloc_size);
@@ -1282,17 +1282,52 @@ static void delete_statement_as_hash_key(void *key)
   delete (Statement *) key;
 }
 
+static byte *get_stmt_name_hash_key(Statement *entry, uint *length,
+                                    my_bool not_used __attribute__((unused)))
+{
+  *length=(uint) entry->name.length;
+  return (byte*) entry->name.str;
+}
+
 C_MODE_END
 
 Statement_map::Statement_map() :
   last_found_statement(0)
 {
-  enum { START_HASH_SIZE = 16 };
-  hash_init(&st_hash, default_charset_info, START_HASH_SIZE, 0, 0,
+  enum
+  {
+    START_STMT_HASH_SIZE = 16,
+    START_NAME_HASH_SIZE = 16
+  };
+  hash_init(&st_hash, default_charset_info, START_STMT_HASH_SIZE, 0, 0,
             get_statement_id_as_hash_key,
             delete_statement_as_hash_key, MYF(0));
+  hash_init(&names_hash, &my_charset_bin, START_NAME_HASH_SIZE, 0, 0,
+            (hash_get_key) get_stmt_name_hash_key,
+            NULL,MYF(0));
 }
 
+int Statement_map::insert(Statement *statement)
+{
+  int rc= my_hash_insert(&st_hash, (byte *) statement);
+  if (rc == 0)
+    last_found_statement= statement;
+  if (statement->name.str)
+  {
+    /*
+      If there is a statement with the same name, remove it. It is ok to 
+      remove old and fail to insert new one at the same time.
+    */
+    Statement *old_stmt;
+    if ((old_stmt= find_by_name(&statement->name)))
+      erase(old_stmt); 
+    if ((rc= my_hash_insert(&names_hash, (byte*)statement)))
+      hash_delete(&st_hash, (byte*)statement);
+  }
+  return rc;
+}
+
+
 bool select_dumpvar::send_data(List<Item> &items)
 {
   List_iterator_fast<Item_func_set_user_var> li(vars);

sql/sql_class.h

@@ -456,6 +456,7 @@ public:
   */
   bool allow_sum_func;
 
+  LEX_STRING name; /* name for named prepared statements */
   LEX *lex;                                     // parse tree descriptor
   /*
     Points to the query associated with this statement. It's const, but
@@ -522,8 +523,14 @@ public:
 
 
 /*
-  Used to seek all existing statements in the connection
-  Deletes all statements in destructor.
+  Container for all statements created/used in a connection.
+  Statements in Statement_map have unique Statement::id (guaranteed by id
+  assignment in Statement::Statement)
+  Non-empty statement names are unique too: attempt to insert a new statement
+  with duplicate name causes older statement to be deleted
+  
+  Statements are auto-deleted when they are removed from the map and when the
+  map is deleted.
 */
 
 class Statement_map
@@ -531,12 +538,14 @@ class Statement_map
 public:
   Statement_map();
   
-  int insert(Statement *statement)
+  int insert(Statement *statement);
+
+  Statement *find_by_name(LEX_STRING *name)
   {
-    int rc= my_hash_insert(&st_hash, (byte *) statement);
-    if (rc == 0)
-      last_found_statement= statement;
-    return rc;
+    Statement *stmt;
+    stmt= (Statement*)hash_search(&names_hash, (byte*)name->str,
+                                  name->length);
+    return stmt;
   }
 
   Statement *find(ulong id)
@@ -550,15 +559,21 @@ public:
   {
     if (statement == last_found_statement)
       last_found_statement= 0;
+    if (statement->name.str)
+    {
+      hash_delete(&names_hash, (byte *) statement);  
+    }
     hash_delete(&st_hash, (byte *) statement);
   }
 
   ~Statement_map()
   {
     hash_free(&st_hash);
+    hash_free(&names_hash);
   }
 private:
   HASH st_hash;
+  HASH names_hash;
   Statement *last_found_statement;
 };
 

sql/sql_lex.h

@@ -76,6 +76,7 @@ enum enum_sql_command {
   SQLCOM_SHOW_COLUMN_TYPES, SQLCOM_SHOW_STORAGE_ENGINES, SQLCOM_SHOW_PRIVILEGES,
   SQLCOM_HELP, SQLCOM_DROP_USER, SQLCOM_REVOKE_ALL, SQLCOM_CHECKSUM,
 
+  SQLCOM_PREPARE, SQLCOM_EXECUTE, SQLCOM_DEALLOCATE_PREPARE,
   /* This should be the last !!! */
   SQLCOM_END
 };
@@ -592,6 +593,11 @@ typedef struct st_lex
   bool in_comment, ignore_space, verbose, simple_alter, no_write_to_binlog;
   bool derived_tables;
   bool safe_to_cache_query;
+  /* Prepared statements SQL syntax:*/
+  LEX_STRING prepared_stmt_name; /* Statement name (in all queries) */
+  LEX_STRING prepared_stmt_code; /* Statement query (in PREPARE )*/
+  /* Names of user variables holding parameters (in EXECUTE) */
+  List<LEX_STRING> prepared_stmt_params; 
   st_lex() {}
   inline void uncacheable(uint8 cause)
   {

sql/sql_parse.cc

@@ -1964,7 +1964,44 @@ mysql_execute_command(THD *thd)
     }
     break;
   }
-
+  case SQLCOM_PREPARE:
+  {   
+    DBUG_PRINT("info", ("PREPARE: %.*s FROM '%.*s' \n", 
+                        lex->prepared_stmt_name.length,
+                        lex->prepared_stmt_name.str,
+                        lex->prepared_stmt_code.length,
+                        lex->prepared_stmt_code.str));
+    thd->command= COM_PREPARE;
+    if (!mysql_stmt_prepare(thd, lex->prepared_stmt_code.str,
+                            lex->prepared_stmt_code.length + 1, 
+                            &lex->prepared_stmt_name))    
+      send_ok(thd, 0L, 0L, "Statement prepared");
+    break;
+  }
+  case SQLCOM_EXECUTE:
+  {
+    DBUG_PRINT("info", ("EXECUTE: %.*s\n", 
+                        lex->prepared_stmt_name.length,
+                        lex->prepared_stmt_name.str));
+    mysql_sql_stmt_execute(thd, &lex->prepared_stmt_name);
+    lex->prepared_stmt_params.empty();
+    break;
+  }
+  case SQLCOM_DEALLOCATE_PREPARE:
+  {
+    Statement* stmt;
+    DBUG_PRINT("info", ("DEALLOCATE PREPARE: %.*s\n", 
+                        lex->prepared_stmt_name.length,
+                        lex->prepared_stmt_name.str));
+    if ((stmt= thd->stmt_map.find_by_name(&lex->prepared_stmt_name)))
+    {
+      thd->stmt_map.erase(stmt);
+      send_ok(thd);
+    }
+    else
+      send_error(thd,ER_UNKNOWN_STMT_HANDLER,"Undefined prepared statement");
+    break;
+  }
   case SQLCOM_DO:
     if (tables && ((res= check_table_access(thd, SELECT_ACL, tables,0)) ||
 		   (res= open_and_lock_tables(thd,tables))))

sql/sql_yacc.yy

@@ -432,6 +432,8 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 %token	MEDIUMTEXT
 %token	NUMERIC_SYM
 %token	PRECISION
+%token  PREPARE_SYM
+%token  DEALLOCATE_SYM
 %token	QUICK
 %token	REAL
 %token	SIGNED_SYM
@@ -724,6 +726,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 	precision subselect_start opt_and charset
 	subselect_end select_var_list select_var_list_init help opt_len
 	opt_extended_describe
+        prepare execute deallocate 
 END_OF_INPUT
 
 %type <NONE>
@@ -760,10 +763,12 @@ verb_clause:
 	| checksum
 	| commit
 	| create
+        | deallocate 
 	| delete
 	| describe
 	| do
 	| drop
+        | execute 
 	| flush
 	| grant
 	| handler
@@ -775,6 +780,7 @@ verb_clause:
 	| optimize
         | keycache
 	| preload
+        | prepare 
 	| purge
 	| rename
 	| repair
@@ -795,6 +801,71 @@ verb_clause:
 	| use
         ;
 
+deallocate:
+        DEALLOCATE_SYM PREPARE_SYM ident 
+        {
+          THD *thd=YYTHD;
+          LEX *lex= thd->lex;
+          if (thd->command == COM_PREPARE)
+          {
+            yyerror(ER(ER_SYNTAX_ERROR));
+            YYABORT;
+          }
+          lex->sql_command= SQLCOM_DEALLOCATE_PREPARE;
+          lex->prepared_stmt_name= $3;
+        };
+
+prepare:
+        PREPARE_SYM ident FROM TEXT_STRING_sys
+        {
+          THD *thd=YYTHD;
+          LEX *lex= thd->lex;
+          if (thd->command == COM_PREPARE)
+          {
+            yyerror(ER(ER_SYNTAX_ERROR));
+            YYABORT;
+          }
+          lex->sql_command= SQLCOM_PREPARE;
+          lex->prepared_stmt_name= $2;
+          lex->prepared_stmt_code= $4;
+        };
+
+execute:
+        EXECUTE_SYM ident
+        {
+          THD *thd=YYTHD;
+          LEX *lex= thd->lex;
+          if (thd->command == COM_PREPARE)
+          {
+            yyerror(ER(ER_SYNTAX_ERROR));
+            YYABORT;
+          }
+          lex->sql_command= SQLCOM_EXECUTE;
+          lex->prepared_stmt_name= $2;
+        }
+        execute_using
+        {}
+        ;
+
+execute_using:
+        /* nothing */
+        | USING execute_var_list
+        ;
+
+execute_var_list:
+        execute_var_list ',' execute_var_ident
+        | execute_var_ident
+        ;
+
+execute_var_ident: '@' ident_or_text
+        {
+          LEX *lex=Lex;
+          LEX_STRING *lexstr= (LEX_STRING*)sql_memdup(&$2, sizeof(LEX_STRING));
+          if (!lexstr || lex->prepared_stmt_params.push_back(lexstr))
+              YYABORT;
+        }
+        ;
+
 /* help */
 
 help:
@@ -4900,6 +4971,7 @@ keyword:
 	| DATETIME		{}
 	| DATE_SYM		{}
 	| DAY_SYM		{}
+        | DEALLOCATE_SYM        {}
 	| DELAY_KEY_WRITE_SYM	{}
 	| DES_KEY_FILE		{}
 	| DIRECTORY_SYM		{}
@@ -4998,6 +5070,7 @@ keyword:
 	| PASSWORD		{}
 	| POINT_SYM		{}
 	| POLYGON		{}
+        | PREPARE_SYM           {}
 	| PREV_SYM		{}
 	| PROCESS		{}
 	| PROCESSLIST_SYM	{}