Bug#25411 (trigger code truncated), PART I

The issue found with bug 25411 is due to the function skip_rear_comments()
which damages the source code while implementing a work around.
The root cause of the problem is in the lexical analyser, which does not
process special comments properly.
For special comments like :
[1] aaa /*!50000 bbb */ ccc
since 5.0 is a version older that the current code, the parser is in lining
the content of the special comment, so that the query to process is
[2] aaa bbb ccc
However, the text of the query captured when processing a stored procedure,
stored function or trigger (or event in 5.1), can be after rebuilding it:
[3] aaa bbb */ ccc
which is wrong.

To fix bug 25411 properly, the lexical analyser needs to return [2] when
in lining special comments.
In order to implement this, some preliminary cleanup is required in the code,
which is implemented by this patch.

Before this change, the structure named LEX (or st_lex) contains attributes
that belong to lexical analysis, as well as attributes that represents the
abstract syntax tree (AST) of a statement.
Creating a new LEX structure for each statements (which makes sense for the
AST part) also re-initialized the lexical analysis phase each time, which
is conceptually wrong.

With this patch, the previous st_lex structure has been split in two:
- st_lex represents the Abstract Syntax Tree for a statement. The name "lex"
has not been changed to avoid a bigger impact in the code base.
- class lex_input_stream represents the internal state of the lexical
  analyser, which by definition should *not* be reinitialized when parsing
  multiple statements from the same input stream.

This change is a pre-requisite for bug 25411, since the implementation of
lex_input_stream will later improve to deal properly with special comments,
and this processing can not be done with the current implementation of
sp_head::reset_lex and sp_head::restore_lex, which interfere with the lexer.

This change set alone does not fix bug 25411.


sql/item_func.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/log_event.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/mysql_priv.h:
  Refactoring, separate lex_input_stream from st_lex.
sql/slave.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sp.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sp_head.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sp_head.h:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_class.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_class.h:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_lex.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_lex.h:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_parse.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_prepare.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_trigger.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_view.cc:
  Refactoring, separate lex_input_stream from st_lex.
sql/sql_yacc.yy:
  Refactoring, separate lex_input_stream from st_lex.

1 files changed, 4 insertions, 2 deletions

diff --git a/sql/sp_head.h b/sql/sp_head.h
index cce400d6a14..4632f6808fd 100644
--- a/sql/sp_head.h
+++ b/sql/sp_head.h
@@ -125,7 +125,7 @@ public:
 
   create_field m_return_field_def; /* This is used for FUNCTIONs only. */
 
-  uchar *m_tmp_query;		// Temporary pointer to sub query string
+  const char *m_tmp_query;	// Temporary pointer to sub query string
   uint m_old_cmq;		// Old CLIENT_MULTI_QUERIES value
   st_sp_chistics *m_chistics;
   ulong m_sql_mode;		// For SHOW CREATE and execution
@@ -174,7 +174,9 @@ public:
   */
   HASH m_sroutines;
   // Pointers set during parsing
-  uchar *m_param_begin, *m_param_end, *m_body_begin;
+  const char *m_param_begin;
+  const char *m_param_end;
+  const char *m_body_begin;
 
   /*
     Security context for stored routine which should be run under