Implementation of mysql_stmt_attr_get and mysql_stmt_attr_set

requested by Monty for Bug#1647 (No way to determine what size 
blob/clob is being returned into bound buffer)

include/mysql.h

@@ -589,8 +589,25 @@ typedef struct st_mysql_stmt
   my_bool        bind_result_done;     /* output buffers were supplied */
   /* mysql_stmt_close() had to cancel this result */
   my_bool       unbuffered_fetch_cancelled;  
+  /*
+    Is set to true if we need to calculate field->max_length for 
+    metadata fields when doing mysql_stmt_store_result.
+  */
+  my_bool       update_max_length;     
 } MYSQL_STMT;
 
+enum enum_stmt_attr_type
+{
+  /*
+    When doing mysql_stmt_store_result calculate max_length attribute
+    of statement metadata. This is to be consistent with the old API, 
+    where this was done automatically.
+    In the new API we do that only by request because it slows down
+    mysql_stmt_store_result sufficiently.
+  */
+  STMT_ATTR_UPDATE_MAX_LENGTH
+};
+
 
 typedef struct st_mysql_methods
 {
@@ -648,6 +665,12 @@ int STDCALL mysql_stmt_fetch_column(MYSQL_STMT *stmt, MYSQL_BIND *bind,
                                     unsigned long offset);
 int STDCALL mysql_stmt_store_result(MYSQL_STMT *stmt);
 unsigned long STDCALL mysql_stmt_param_count(MYSQL_STMT * stmt);
+my_bool STDCALL mysql_stmt_attr_set(MYSQL_STMT *stmt,
+                                    enum enum_stmt_attr_type attr_type,
+                                    const void *attr);
+my_bool STDCALL mysql_stmt_attr_get(MYSQL_STMT *stmt,
+                                    enum enum_stmt_attr_type attr_type,
+                                    void *attr);
 my_bool STDCALL mysql_stmt_bind_param(MYSQL_STMT * stmt, MYSQL_BIND * bnd);
 my_bool STDCALL mysql_stmt_bind_result(MYSQL_STMT * stmt, MYSQL_BIND * bnd);
 my_bool STDCALL mysql_stmt_close(MYSQL_STMT * stmt);

libmysql/libmysql.c

@@ -2514,6 +2514,56 @@ stmt_read_row_no_data(MYSQL_STMT *stmt  __attribute__((unused)),
   return MYSQL_NO_DATA;
 }
 
+
+/*
+  Get/set statement attributes
+
+  SYNOPSIS
+    mysql_stmt_attr_get()
+    mysql_stmt_attr_set()
+
+    attr_type  statemenet attribute
+    value      casted to const void * pointer to value.
+
+  RETURN VALUE
+    0 success
+   !0 wrong attribute type
+*/
+        
+my_bool STDCALL mysql_stmt_attr_set(MYSQL_STMT *stmt,
+                                    enum enum_stmt_attr_type attr_type,
+                                    const void *value)
+{
+  switch (attr_type) {
+  case STMT_ATTR_UPDATE_MAX_LENGTH:
+    /*
+      Do we need a flags variable for all attributes or a bool for each
+      attribute?
+    */
+    stmt->update_max_length= value ? *(const my_bool*) value : 0;
+    break;
+  default: 
+    return TRUE;
+  }
+  return FALSE;
+}
+
+
+my_bool STDCALL mysql_stmt_attr_get(MYSQL_STMT *stmt, 
+                                    enum enum_stmt_attr_type attr_type,
+                                    void *value)
+{
+  switch (attr_type) {
+  case STMT_ATTR_UPDATE_MAX_LENGTH:
+    *(unsigned long *) value= stmt->update_max_length;
+      break;
+  default: 
+    return TRUE;
+  }
+  return FALSE;
+}
+
+
 /*
   Execute the prepared query
 */

libmysql/libmysql.def

@@ -127,3 +127,5 @@ EXPORTS
 	mysql_stmt_prepare
 	mysql_stmt_init
 	mysql_stmt_insert_id
+        mysql_stmt_attr_get
+        mysql_stmt_attr_set