WL#1218 "Triggers". Some very preliminary version of patch.

Mostly needed for Monty for him getting notion what needed for triggers 
from new .FRM format. 

Things to be done:
- Right placement of trigger's invocations
- Right handling of errors in triggers (including transaction rollback)
- Support for priviliges
- Right handling of DROP/RENAME table (hope that it will be handled automatically
  with merging of .TRG into .FRM file)
- Saving/restoring some information critical for trigger creation and replication
  with their definitions (e.g. sql_mode, creator, ...)
- Replication

Already has some known bugs so probably not for general review.


include/mysqld_error.h:
  Added trigger related error codes.
sql/Makefile.am:
  Added sql_trigger.* files to list of sources from which mysqld is built.
sql/item.cc:
  Added Item_trigger_field class representing field of new/old version of row which is 
  inserted/updated/deleted and for which trigger is invoked.
sql/item.h:
  Added enums for describing trigger properties. (Here because of dependencies).
  Added Item_trigger_field class representing field of new/old version of row which is 
  inserted/updated/deleted and for which trigger is invoked.
sql/item_func.cc:
  Added Item_func_set_user_var::print_as_stmt() for printing of assignment to ser variable
  from stored procedures.
  Added comment clarifying why we don't need set no_send_ok when calling stored functions.
sql/item_func.h:
  Added Item_func_set_user_var::print_as_stmt() for printing of assignment to ser variable
  from stored procedures.
sql/lex.h:
  Symbols used in statements defining triggers were added.
sql/mysql_priv.h:
  Exported some functions needed for triggers implementation.
sql/parse_file.cc:
  Cleaned up FILE_OPTIONS_STRLIST handling (needed for triggers).
sql/parse_file.h:
  Cleaned up FILE_OPTIONS_STRLIST handling (needed for triggers).
sql/share/czech/errmsg.txt:
  Added trigger related error messages.
sql/share/danish/errmsg.txt:
  Added trigger related error messages.
sql/share/dutch/errmsg.txt:
  Added trigger related error messages.
sql/share/english/errmsg.txt:
  Added trigger related error messages.
sql/share/estonian/errmsg.txt:
  Added trigger related error messages.
sql/share/french/errmsg.txt:
  Added trigger related error messages.
sql/share/german/errmsg.txt:
  Added trigger related error messages.
sql/share/greek/errmsg.txt:
  Added trigger related error messages.
sql/share/hungarian/errmsg.txt:
  Added trigger related error messages.
sql/share/italian/errmsg.txt:
  Added trigger related error messages.
sql/share/japanese/errmsg.txt:
  Added trigger related error messages.
sql/share/korean/errmsg.txt:
  Added trigger related error messages.
sql/share/norwegian-ny/errmsg.txt:
  Added trigger related error messages.
sql/share/norwegian/errmsg.txt:
  Added trigger related error messages.
sql/share/polish/errmsg.txt:
  Added trigger related error messages.
sql/share/portuguese/errmsg.txt:
  Added trigger related error messages.
sql/share/romanian/errmsg.txt:
  Added trigger related error messages.
sql/share/russian/errmsg.txt:
  Added trigger related error messages.
sql/share/serbian/errmsg.txt:
  Added trigger related error messages.
sql/share/slovak/errmsg.txt:
  Added trigger related error messages.
sql/share/spanish/errmsg.txt:
  Added trigger related error messages.
sql/share/swedish/errmsg.txt:
  Added trigger related error messages.
sql/share/ukrainian/errmsg.txt:
  Added trigger related error messages.
sql/sp_head.cc:
  sp_head::init_strings(): added support for triggers 
    (we don't have most of strings for them)
  sp_head::execute_function(): triggers don't require RETURN
  sp_head::reset_lex(): added propagation of trigger properties to LEX used for 
   parsing of statements composing trigger body.
  Added two more SP instructions:
  - sp_instr_set_user_var for setting user variables in stored functions and triggers
    (we can't use sp_instr_stmt and "SET @a:=..." statement since it will close open 
    tables and thus break execution of calling statement.
  - sp_instr_set_trigger_field for assignment to fields of row being updated/inserted in
    triggers
sql/sp_head.h:
  Added new type of sp_head object - TYPE_ENUM_TRIGGER
  Added two more SP instructions:
  - sp_instr_set_user_var for setting user variables in stored functions and triggers
    (we can't use sp_instr_stmt and "SET @a:=..." statement since it will close open 
    tables and thus break execution of calling statement.
  - sp_instr_set_trigger_field for assignment to fields of row being updated/inserted in
    triggers
sql/sql_base.cc:
  Now freeing memory occupied by trigger related structures when closing tables.
  open_unireg_entry(): added loading of triggers for table.
  find_field_in_real_table() is now public since it required by Item_trigger_field in item.cc
sql/sql_delete.cc:
  Added triggers invocation for DELETE (should be fixed for sure :))
sql/sql_insert.cc:
  Added triggers invocation for INSERT (should be fixed for sure :))
sql/sql_lex.cc:
  Added trg_new_row_fake_var variable pointer to which is used for distinguishing between
  assignment to NEW row field (when parsing trigger definition) and structured variable.
  Added initialization of LEX->trg_table to lex_start(). (When triggers are parsed during
  opening of table it points to table object.)
sql/sql_lex.h:
  Added trigger related commands.
  Added st_trg_chistics structure describing properties of trigger being created
  (as struct and as LEX member).
  Added trg_new_row_fake_var variable pointer to which is used for
  distinguishing between assignment to NEW row field (when parsing trigger definition)
  and structured variable.
  Added LEX::trg_table which points to table being opened when we are parsing trigger
  definition while opening table.
sql/sql_parse.cc:
  Added support for CREATE/DROP TRIGGER commands.
sql/sql_table.cc:
  Cleanup. close_cached_table() always returns 0 and its result is not analyzed in most
  places so chenged its return type to void.
sql/sql_update.cc:
  Added triggers invocation for UPDATE (should be fixed for sure :))
sql/sql_yacc.yy:
  Added support for CREATE/DROP TRIGGER statements.
  Added support for OLD/NEW row identifiers in trigger.
  Made assignment to user variables not to break execution of stored function or trigger.
sql/table.h:
  Added TABLE::triggers member representing triggers for this table.

1 files changed, 90 insertions, 19 deletions

diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index 89114e4f62b..44357170ff5 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -242,31 +242,43 @@ sp_head::init_strings(THD *thd, LEX *lex, sp_name *name)
   /* During parsing, we must use thd->mem_root */
   MEM_ROOT *root= &thd->mem_root;
 
-  DBUG_PRINT("info", ("name: %*.s%*s",
-		      name->m_db.length, name->m_db.str,
-		      name->m_name.length, name->m_name.str));
   /* We have to copy strings to get them into the right memroot */
-  if (name->m_db.length == 0)
+  if (name)
+  {
+    DBUG_PRINT("info", ("name: %*.s%*s",
+                        name->m_db.length, name->m_db.str,
+		        name->m_name.length, name->m_name.str));
+    
+    if (name->m_db.length == 0)
+    {
+      m_db.length= (thd->db ? strlen(thd->db) : 0);
+      m_db.str= strmake_root(root, (thd->db ? thd->db : ""), m_db.length);
+    }
+    else
+    {
+      m_db.length= name->m_db.length;
+      m_db.str= strmake_root(root, name->m_db.str, name->m_db.length);
+    }
+    m_name.length= name->m_name.length;
+    m_name.str= strmake_root(root, name->m_name.str, name->m_name.length);
+
+    if (name->m_qname.length == 0)
+      name->init_qname(thd);
+    m_qname.length= name->m_qname.length;
+    m_qname.str= strmake_root(root, name->m_qname.str, m_qname.length);
+  }
+  else
   {
     m_db.length= (thd->db ? strlen(thd->db) : 0);
     m_db.str= strmake_root(root, (thd->db ? thd->db : ""), m_db.length);
   }
-  else
+  
+  if (m_param_begin && m_param_end)
   {
-    m_db.length= name->m_db.length;
-    m_db.str= strmake_root(root, name->m_db.str, name->m_db.length);
+    m_params.length= m_param_end - m_param_begin;
+    m_params.str= strmake_root(root,
+                               (char *)m_param_begin, m_params.length);
   }
-  m_name.length= name->m_name.length;
-  m_name.str= strmake_root(root, name->m_name.str, name->m_name.length);
-
-  if (name->m_qname.length == 0)
-    name->init_qname(thd);
-  m_qname.length= name->m_qname.length;
-  m_qname.str= strmake_root(root, name->m_qname.str, m_qname.length);
-
-  m_params.length= m_param_end- m_param_begin;
-  m_params.str= strmake_root(root,
-			     (char *)m_param_begin, m_params.length);
   if (m_returns_begin && m_returns_end)
   {
     /* QQ KLUDGE: We can't seem to cut out just the type in the parser
@@ -508,8 +520,10 @@ sp_head::execute_function(THD *thd, Item **argp, uint argcount, Item **resp)
   thd->spcont= nctx;
 
   ret= execute(thd);
-  if (ret == 0)
+
+  if (m_type == TYPE_ENUM_FUNCTION && ret == 0)
   {
+    /* We need result only in function but not in trigger */
     Item *it= nctx->get_result();
 
     if (it)
@@ -683,6 +697,9 @@ sp_head::reset_lex(THD *thd)
   /* And keep the SP stuff too */
   sublex->sphead= oldlex->sphead;
   sublex->spcont= oldlex->spcont;
+  /* And trigger related stuff too */
+  sublex->trg_chistics= oldlex->trg_chistics;
+  sublex->trg_table= oldlex->trg_table;
   mysql_init_query(thd, true);	// Only init lex
   sublex->sp_lex_in_use= FALSE;
   DBUG_VOID_RETURN;
@@ -1041,6 +1058,60 @@ sp_instr_set::print(String *str)
 }
 
 //
+// sp_instr_set_user_var
+//
+int
+sp_instr_set_user_var::execute(THD *thd, uint *nextp)
+{
+  int res= 0;
+
+  DBUG_ENTER("sp_instr_set_user_var::execute");
+  /*
+    It is ok to pass 0 as 3rd argument to fix_fields() since
+    Item_func_set_user_var::fix_fields() won't use it.
+    QQ: Still unsure what should we return in case of error 1 or -1 ?
+  */
+  if (!m_set_var_item.fixed && m_set_var_item.fix_fields(thd, 0, 0) ||
+      m_set_var_item.check() || m_set_var_item.update())
+    res= -1;
+  *nextp= m_ip + 1;
+  DBUG_RETURN(res);
+}
+
+void
+sp_instr_set_user_var::print(String *str)
+{
+  m_set_var_item.print_as_stmt(str);
+}
+
+//
+// sp_instr_set_trigger_field
+//
+int
+sp_instr_set_trigger_field::execute(THD *thd, uint *nextp)
+{
+  int res= 0;
+
+  DBUG_ENTER("sp_instr_set_trigger_field::execute");
+  /* QQ: Still unsure what should we return in case of error 1 or -1 ? */
+  if (!value->fixed && value->fix_fields(thd, 0, &value) ||
+      trigger_field.fix_fields(thd, 0, 0) ||
+      (value->save_in_field(trigger_field.field, 0) < 0))
+    res= -1;
+  *nextp= m_ip + 1;
+  DBUG_RETURN(res);
+}
+
+void
+sp_instr_set_trigger_field::print(String *str)
+{
+  str->append("set ", 4);
+  trigger_field.print(str);
+  str->append(":=", 2);
+  value->print(str);
+}
+
+//
 // sp_instr_jump
 //
 int