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, 66 insertions, 0 deletions

diff --git a/sql/sp_head.h b/sql/sp_head.h
index fd6ecfd7320..1622d197d81 100644
--- a/sql/sp_head.h
+++ b/sql/sp_head.h
@@ -28,6 +28,7 @@
 // in the CREATE TABLE command.
 #define TYPE_ENUM_FUNCTION  1
 #define TYPE_ENUM_PROCEDURE 2
+#define TYPE_ENUM_TRIGGER   3
 
 Item_result
 sp_map_result_type(enum enum_field_types type);
@@ -342,6 +343,71 @@ private:
 }; // class sp_instr_set : public sp_instr
 
 
+/*
+  Set user variable instruction.
+  Used in functions and triggers to set user variables because we don't
+  want use sp_instr_stmt + "SET @a:=..." statement in this case since
+  latter will close all tables and thus will ruin execution of statement
+  calling/invoking this function/trigger.
+*/
+class sp_instr_set_user_var : public sp_instr
+{
+  sp_instr_set_user_var(const sp_instr_set_user_var &);
+  void operator=(sp_instr_set_user_var &);
+
+public:
+
+  sp_instr_set_user_var(uint ip, LEX_STRING var, Item *val)
+    : sp_instr(ip), m_set_var_item(var, val)
+  {}
+
+  virtual ~sp_instr_set_user_var()
+  {}
+
+  virtual int execute(THD *thd, uint *nextp);
+
+  virtual void print(String *str);
+
+private:
+
+  Item_func_set_user_var m_set_var_item;
+}; // class sp_instr_set_user_var : public sp_instr
+
+
+/*
+  Set NEW/OLD row field value instruction. Used in triggers.
+*/
+class sp_instr_set_trigger_field : public sp_instr
+{
+  sp_instr_set_trigger_field(const sp_instr_set_trigger_field &);
+  void operator=(sp_instr_set_trigger_field &);
+
+public:
+
+  sp_instr_set_trigger_field(uint ip, LEX_STRING field_name, Item *val)
+    : sp_instr(ip),
+      trigger_field(Item_trigger_field::NEW_ROW, field_name.str),
+      value(val)
+  {}
+
+  virtual ~sp_instr_set_trigger_field()
+  {}
+
+  virtual int execute(THD *thd, uint *nextp);
+
+  virtual void print(String *str);
+
+  bool setup_field(THD *thd, TABLE *table, enum trg_event_type event)
+  {
+    return trigger_field.setup_field(thd, table, event);
+  }
+private:
+
+  Item_trigger_field trigger_field;
+  Item *value;
+}; // class sp_instr_trigger_field : public sp_instr
+
+
 class sp_instr_jump : public sp_instr
 {
   sp_instr_jump(const sp_instr_jump &);	/* Prevent use of these */