Merge MariaDB 10.0-base to MariaDB 10.0

1 files changed, 116 insertions, 97 deletions

diff --git a/sql/field.cc b/sql/field.cc
index e0ecd6ab74f..a18c72119be 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -50,11 +50,6 @@
   Instansiate templates and static variables
 *****************************************************************************/
 
-#ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION
-template class List<Create_field>;
-template class List_iterator<Create_field>;
-#endif
-
 static const char *zero_timestamp="0000-00-00 00:00:00.000000";
 
 /* number of bytes to store second_part part of the TIMESTAMP(N) */
@@ -1817,6 +1812,10 @@ Field *Field::new_field(MEM_ROOT *root, TABLE *new_table,
   tmp->key_start.init(0);
   tmp->part_of_key.init(0);
   tmp->part_of_sortkey.init(0);
+  /*
+    TODO: it is not clear why this method needs to reset unireg_check.
+    Try not to reset it, or explain why it needs to be reset.
+  */
   tmp->unireg_check= Field::NONE;
   tmp->flags&= (NOT_NULL_FLAG | BLOB_FLAG | UNSIGNED_FLAG |
                 ZEROFILL_FLAG | BINARY_FLAG | ENUM_FLAG | SET_FLAG);
@@ -4369,16 +4368,10 @@ void Field_double::sql_type(String &res) const
   2038-01-01 00:00:00 UTC stored as number of seconds since Unix 
   Epoch in UTC.
   
-  Up to one of timestamps columns in the table can be automatically 
-  set on row update and/or have NOW() as default value.
-  TABLE::timestamp_field points to Field object for such timestamp with 
-  auto-set-on-update. TABLE::time_stamp holds offset in record + 1 for this
-  field, and is used by handler code which performs updates required.
-  
   Actually SQL-99 says that we should allow niladic functions (like NOW())
-  as defaults for any field. Current limitations (only NOW() and only 
-  for one TIMESTAMP field) are because of restricted binary .frm format 
-  and should go away in the future.
+  as defaults for any field. The current limitation (only NOW() and only 
+  for TIMESTAMP and DATETIME fields) are because of restricted binary .frm
+  format and should go away in the future.
   
   Also because of this limitation of binary .frm format we use 5 different
   unireg_check values with TIMESTAMP field to distinguish various cases of
@@ -4419,10 +4412,12 @@ Field_timestamp::Field_timestamp(uchar *ptr_arg, uint32 len_arg,
 {
   /* For 4.0 MYD and 4.0 InnoDB compatibility */
   flags|= UNSIGNED_FLAG | BINARY_FLAG;
-  if (unireg_check != NONE && !share->timestamp_field)
+  if (unireg_check != NONE)
   {
-    /* This timestamp has auto-update */
-    share->timestamp_field= this;
+    /*
+      We mark the flag with TIMESTAMP_FLAG to indicate to the client that
+      this field will be automaticly updated on insert.
+    */
     flags|= TIMESTAMP_FLAG;
     if (unireg_check != TIMESTAMP_DN_FIELD)
       flags|= ON_UPDATE_NOW_FLAG;
@@ -4430,40 +4425,6 @@ Field_timestamp::Field_timestamp(uchar *ptr_arg, uint32 len_arg,
 }
 
 
-/**
-  Get auto-set type for TIMESTAMP field.
-
-  Returns value indicating during which operations this TIMESTAMP field
-  should be auto-set to current timestamp.
-*/
-timestamp_auto_set_type Field_timestamp::get_auto_set_type() const
-{
-  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_OLD_FIELD:
-    /*
-      Although we can have several such columns in legacy tables this
-      function should be called only for first of them (i.e. the one
-      having auto-set property).
-    */
-    DBUG_ASSERT(table->timestamp_field == this);
-    /* Fall-through */
-  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;
-  }
-}
-
 my_time_t Field_timestamp::get_timestamp(ulong *sec_part) const
 {
   ASSERT_COLUMN_MARKED_FOR_READ;
@@ -4713,6 +4674,34 @@ int Field_timestamp::set_time()
   return 0;
 }
 
+/**
+  Mark the field as having an explicit default value.
+
+  @param value  if available, the value that the field is being set to
+
+  @note
+    Fields that have an explicit default value should not be updated
+    automatically via the DEFAULT or ON UPDATE functions. The functions
+    that deal with data change functionality (INSERT/UPDATE/LOAD),
+    determine if there is an explicit value for each field before performing
+    the data change, and call this method to mark the field.
+
+    For timestamp columns, the only case where a column is not marked
+    as been given a value are:
+    - It's explicitly assigned with DEFAULT
+    - We assign NULL to a timestamp field that is defined as NOT NULL.
+      This is how MySQL has worked since it's start.
+*/
+
+void Field_timestamp::set_explicit_default(Item *value)
+{
+  if (((value->type() == Item::DEFAULT_VALUE_ITEM &&
+        !((Item_default_value*)value)->arg) ||
+       (!maybe_null() && value->is_null())))
+    return;
+  set_has_explicit_value();
+}
+
 void Field_timestamp_hires::sql_type(String &res) const
 {
   CHARSET_INFO *cs=res.charset();
@@ -5834,6 +5823,20 @@ void Field_datetime::sql_type(String &res) const
   res.set_ascii(STRING_WITH_LEN("datetime"));
 }
 
+
+int Field_datetime::set_time()
+{
+  THD *thd= table->in_use;
+  MYSQL_TIME now_time;
+  thd->variables.time_zone->gmt_sec_to_TIME(&now_time, thd->query_start());
+  now_time.second_part= thd->query_start_sec_part();
+  set_notnull();
+  store_TIME(&now_time);
+  thd->time_zone_used= 1;
+  return 0;
+}
+
+
 void Field_datetime_hires::store_TIME(MYSQL_TIME *ltime)
 {
   ulonglong packed= sec_part_shift(pack_time(ltime), dec);
@@ -8855,16 +8858,37 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type,
 {
   uint sign_len, allowed_type_modifier= 0;
   ulong max_field_charlength= MAX_FIELD_CHARLENGTH;
+  const bool on_update_is_function=
+    (fld_on_update_value != NULL &&
+     fld_on_update_value->type() == Item::FUNC_ITEM);
 
   DBUG_ENTER("Create_field::init()");
 
   field= 0;
   field_name= fld_name;
-  def= fld_default_value;
   flags= fld_type_modifier;
   option_list= create_opt;
-  unireg_check= (fld_type_modifier & AUTO_INCREMENT_FLAG ?
-                 Field::NEXT_NUMBER : Field::NONE);
+
+  if (fld_default_value != NULL && fld_default_value->type() == Item::FUNC_ITEM)
+  {
+    /* There is a function default for insertions. */
+    def= NULL;
+    unireg_check= (on_update_is_function ?
+                   Field::TIMESTAMP_DNUN_FIELD : // for insertions and for updates.
+                   Field::TIMESTAMP_DN_FIELD);   // only for insertions.
+  }
+  else
+  {
+    /* No function default for insertions. Either NULL or a constant. */
+    def= fld_default_value;
+    if (on_update_is_function)
+      unireg_check= Field::TIMESTAMP_UN_FIELD; // function default for updates
+    else
+      unireg_check= ((fld_type_modifier & AUTO_INCREMENT_FLAG) != 0 ?
+                     Field::NEXT_NUMBER : // Automatic increment.
+                     Field::NONE);
+  }
+
   decimals= fld_decimals ? (uint)atoi(fld_decimals) : 0;
   if (decimals >= NOT_FIXED_DEC)
   {
@@ -9085,44 +9109,6 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type,
     }
     length+= MAX_DATETIME_WIDTH + (length ? 1 : 0);
     flags|= UNSIGNED_FLAG;
-
-    if (fld_default_value)
-    {
-      /* Grammar allows only NOW() value for ON UPDATE clause */
-      if (fld_default_value->type() == Item::FUNC_ITEM && 
-          ((Item_func*)fld_default_value)->functype() == Item_func::NOW_FUNC)
-      {
-        unireg_check= (fld_on_update_value ? Field::TIMESTAMP_DNUN_FIELD:
-                                             Field::TIMESTAMP_DN_FIELD);
-        /*
-          We don't need default value any longer moreover it is dangerous.
-          Everything handled by unireg_check further.
-        */
-        def= 0;
-      }
-      else
-        unireg_check= (fld_on_update_value ? Field::TIMESTAMP_UN_FIELD:
-                                             Field::NONE);
-    }
-    else
-    {
-      /*
-        If we have default TIMESTAMP NOT NULL column without explicit DEFAULT
-        or ON UPDATE values then for the sake of compatiblity we should treat
-        this column as having DEFAULT NOW() ON UPDATE NOW() (when we don't
-        have another TIMESTAMP column with auto-set option before this one)
-        or DEFAULT 0 (in other cases).
-        So here we are setting TIMESTAMP_OLD_FIELD only temporary, and will
-        replace this value by TIMESTAMP_DNUN_FIELD or NONE later when
-        information about all TIMESTAMP fields in table will be availiable.
-
-        If we have TIMESTAMP NULL column without explicit DEFAULT value
-        we treat it as having DEFAULT NULL attribute.
-      */
-      unireg_check= (fld_on_update_value ? Field::TIMESTAMP_UN_FIELD :
-                     (flags & NOT_NULL_FLAG ? Field::TIMESTAMP_OLD_FIELD :
-                                              Field::NONE));
-    }
     break;
   case MYSQL_TYPE_DATE:
     /* We don't support creation of MYSQL_TYPE_DATE anymore */
@@ -9588,11 +9574,18 @@ Create_field::Create_field(Field *old_field,Field *orig_field)
   def=0;
   char_length= length;
 
-  if (!(flags & (NO_DEFAULT_VALUE_FLAG | BLOB_FLAG)) &&
-      old_field->ptr && orig_field &&
-      (sql_type != MYSQL_TYPE_TIMESTAMP ||                /* set def only if */
-       old_field->table->timestamp_field != old_field ||  /* timestamp field */ 
-       unireg_check == Field::TIMESTAMP_UN_FIELD))        /* has default val */
+  /*
+    Copy the default value from the column object orig_field, if:
+    1) The column has a constant default value.
+    2) The column type is not a BLOB type.
+    3) The original column (old_field) was properly initialized with a record
+       buffer pointer.
+    4) The original column doesn't have a default function to auto-initialize
+       the column on INSERT
+  */
+  if (!(flags & (NO_DEFAULT_VALUE_FLAG | BLOB_FLAG)) && // 1) 2)
+      old_field->ptr && orig_field &&                   // 3)
+      !old_field->has_insert_default_function())        // 4)
   {
     char buff[MAX_FIELD_WIDTH];
     String tmp(buff,sizeof(buff), charset);
@@ -9776,3 +9769,29 @@ key_map Field::get_possible_keys()
   return (table->pos_in_table_list->is_materialized_derived() ?
           part_of_key : key_start);
 }
+
+
+/**
+  Mark the field as having an explicit default value.
+
+  @param value  if available, the value that the field is being set to
+
+  @note
+    Fields that have an explicit default value should not be updated
+    automatically via the DEFAULT or ON UPDATE functions. The functions
+    that deal with data change functionality (INSERT/UPDATE/LOAD),
+    determine if there is an explicit value for each field before performing
+    the data change, and call this method to mark the field.
+
+    If the 'value' parameter is NULL, then the field is marked unconditionally
+    as having an explicit value. If 'value' is not NULL, then it can be further
+    analyzed to check if it really should count as a value.
+*/
+
+void Field::set_explicit_default(Item *value)
+{
+  if (value->type() == Item::DEFAULT_VALUE_ITEM &&
+      !((Item_default_value*)value)->arg)
+    return;
+  set_has_explicit_value();
+}