Support for TIMESTAMP columns holding NULL values. Unlike all other

column types TIMESTAMP is NOT NULL by default, so in order to have 
TIMESTAMP column holding NULL valaues you have to specify NULL as
one of its attributes (this needed for backward compatibility).

Main changes:
Replaced TABLE::timestamp_default_now/on_update_now members with
TABLE::timestamp_auto_set_type flag which is used everywhere
for determining if we should auto-set value of TIMESTAMP field 
during this operation or not. We are also use Field_timestamp::set_time()
instead of handler::update_timestamp() in handlers.

1 files changed, 30 insertions, 17 deletions

diff --git a/sql/field.cc b/sql/field.cc
index 17a89ad02c1..a508b378544 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -2902,11 +2902,12 @@ void Field_double::sql_type(String &res) const
  */
 
 Field_timestamp::Field_timestamp(char *ptr_arg, uint32 len_arg,
+                                 uchar *null_ptr_arg, uchar null_bit_arg,
 				 enum utype unireg_check_arg,
 				 const char *field_name_arg,
 				 struct st_table *table_arg,
 				 CHARSET_INFO *cs)
-  :Field_str(ptr_arg, 19, (uchar*) 0,0,
+  :Field_str(ptr_arg, 19, null_ptr_arg, null_bit_arg,
 	     unireg_check_arg, field_name_arg, table_arg, cs)
 {
   /* For 4.0 MYD and 4.0 InnoDB compatibility */
@@ -2922,23 +2923,33 @@ Field_timestamp::Field_timestamp(char *ptr_arg, uint32 len_arg,
 
 
 /*
-    Sets TABLE::timestamp_default_now and TABLE::timestamp_on_update_now 
-    members according to unireg type of this TIMESTAMP field.
-  
+  Get auto-set type for TIMESTAMP field.
+
   SYNOPSIS
-    Field_timestamp::set_timestamp_offsets()
-  
+    get_auto_set_type()
+
+  DESCRIPTION
+    Returns value indicating during which operations this TIMESTAMP field
+    should be auto-set to current timestamp.
 */
-void Field_timestamp::set_timestamp_offsets()
+timestamp_auto_set_type Field_timestamp::get_auto_set_type() const
 {
-  ulong timestamp= (ulong) (ptr - (char*) table->record[0]) + 1;
-  
-  DBUG_ASSERT(table->timestamp_field == this && unireg_check != NONE);
-
-  table->timestamp_default_now= 
-    (unireg_check == TIMESTAMP_UN_FIELD)? 0 : timestamp;
-  table->timestamp_on_update_now= 
-    (unireg_check == TIMESTAMP_DN_FIELD)? 0 : timestamp;
+  switch (unireg_check)
+  {
+  case TIMESTAMP_DN_FIELD:
+    return TIMESTAMP_AUTO_SET_ON_INSERT;
+  case TIMESTAMP_UN_FIELD:
+    return TIMESTAMP_AUTO_SET_ON_UPDATE;
+  case TIMESTAMP_DNUN_FIELD:
+    return TIMESTAMP_AUTO_SET_ON_BOTH;
+  default:
+    /*
+      Normally this function should not be called for TIMESTAMPs without
+      auto-set property.
+    */
+    DBUG_ASSERT(0);
+    return TIMESTAMP_NO_AUTO_SET;
+  }
 }
 
 
@@ -3237,6 +3248,7 @@ void Field_timestamp::sql_type(String &res) const
 void Field_timestamp::set_time()
 {
   long tmp= (long) table->in_use->query_start();
+  set_notnull();
 #ifdef WORDS_BIGENDIAN
   if (table->db_low_byte_first)
   {
@@ -5917,8 +5929,9 @@ Field *make_field(char *ptr, uint32 field_length,
 			      f_is_zerofill(pack_flag) != 0,
 			      f_is_dec(pack_flag) == 0);
   case FIELD_TYPE_TIMESTAMP:
-    return new Field_timestamp(ptr,field_length,
-			       unireg_check, field_name, table, field_charset);
+    return new Field_timestamp(ptr,field_length, null_pos, null_bit,
+                               unireg_check, field_name, table,
+                               field_charset);
   case FIELD_TYPE_YEAR:
     return new Field_year(ptr,field_length,null_pos,null_bit,
 			  unireg_check, field_name, table);