Patch for the following bugs:

- BUG#11986: Stored routines and triggers can fail if the code
    has a non-ascii symbol
  - BUG#16291: mysqldump corrupts string-constants with non-ascii-chars
  - BUG#19443: INFORMATION_SCHEMA does not support charsets properly
  - BUG#21249: Character set of SP-var can be ignored
  - BUG#25212: Character set of string constant is ignored (stored routines)
  - BUG#25221: Character set of string constant is ignored (triggers)

There were a few general problems that caused these bugs:
1. Character set information of the original (definition) query for views,
   triggers, stored routines and events was lost.
2. mysqldump output query in client character set, which can be
   inappropriate to encode definition-query.
3. INFORMATION_SCHEMA used strings with mixed encodings to display object
   definition;

1. No query-definition-character set.

In order to compile query into execution code, some extra data (such as
environment variables or the database character set) is used. The problem
here was that this context was not preserved. So, on the next load it can
differ from the original one, thus the result will be different.

The context contains the following data:
  - client character set;
  - connection collation (character set and collation);
  - collation of the owner database;

The fix is to store this context and use it each time we parse (compile)
and execute the object (stored routine, trigger, ...).

2. Wrong mysqldump-output.

The original query can contain several encodings (by means of character set
introducers). The problem here was that we tried to convert original query
to the mysqldump-client character set.

Moreover, we stored queries in different character sets for different
objects (views, for one, used UTF8, triggers used original character set).

The solution is
  - to store definition queries in the original character set;
  - to change SHOW CREATE statement to output definition query in the
    binary character set (i.e. without any conversion);
  - introduce SHOW CREATE TRIGGER statement;
  - to dump special statements to switch the context to the original one
    before dumping and restore it afterwards.

Note, in order to preserve the database collation at the creation time,
additional ALTER DATABASE might be used (to temporary switch the database
collation back to the original value). In this case, ALTER DATABASE
privilege will be required. This is a backward-incompatible change.

3. INFORMATION_SCHEMA showed non-UTF8 strings

The fix is to generate UTF8-query during the parsing, store it in the object
and show it in the INFORMATION_SCHEMA.

Basically, the idea is to create a copy of the original query convert it to
UTF8. Character set introducers are removed and all text literals are
converted to UTF8.

This UTF8 query is intended to provide user-readable output. It must not be
used to recreate the object.  Specialized SHOW CREATE statements should be
used for this.

The reason for this limitation is the following: the original query can
contain symbols from several character sets (by means of character set
introducers).

Example:

  - original query:
    CREATE VIEW v1 AS SELECT _cp1251 'Hello' AS c1;

  - UTF8 query (for INFORMATION_SCHEMA):
    CREATE VIEW v1 AS SELECT 'Hello' AS c1;

sql/mysql_priv.h

@@ -150,6 +150,86 @@ extern MY_LOCALE *my_default_lc_time_names;
 MY_LOCALE *my_locale_by_name(const char *name);
 MY_LOCALE *my_locale_by_number(uint number);
 
+/*************************************************************************/
+
+/**
+ Object_creation_ctx -- interface for creation context of database objects
+ (views, stored routines, events, triggers). Creation context -- is a set
+ of attributes, that should be fixed at the creation time and then be used
+ each time the object is parsed or executed.
+*/
+
+class Object_creation_ctx
+{
+public:
+  Object_creation_ctx *set_n_backup(THD *thd);
+
+  void restore_env(THD *thd, Object_creation_ctx *backup_ctx);
+
+protected:
+  virtual Object_creation_ctx *create_backup_ctx(THD *thd) = 0;
+
+  virtual void change_env(THD *thd) const = 0;
+
+public:
+  virtual ~Object_creation_ctx()
+  { }
+};
+
+/*************************************************************************/
+
+/**
+ Default_object_creation_ctx -- default implementation of
+ Object_creation_ctx.
+*/
+
+class Default_object_creation_ctx : public Object_creation_ctx
+{
+public:
+  CHARSET_INFO *get_client_cs()
+  {
+    return m_client_cs;
+  }
+
+  CHARSET_INFO *get_connection_cl()
+  {
+    return m_connection_cl;
+  }
+
+protected:
+  Default_object_creation_ctx(THD *thd);
+
+  Default_object_creation_ctx(CHARSET_INFO *client_cs,
+                              CHARSET_INFO *connection_cl);
+
+protected:
+  virtual Object_creation_ctx *create_backup_ctx(THD *thd);
+
+  virtual void change_env(THD *thd) const;
+
+protected:
+  /**
+    client_cs stores the value of character_set_client session variable.
+    The only character set attribute is used.
+
+    Client character set is included into query context, because we save
+    query in the original character set, which is client character set. So,
+    in order to parse the query properly we have to switch client character
+    set on parsing.
+  */
+  CHARSET_INFO *m_client_cs;
+
+  /**
+    connection_cl stores the value of collation_connection session
+    variable. Both character set and collation attributes are used.
+
+    Connection collation is included into query context, becase it defines
+    the character set and collation of text literals in internal
+    representation of query (item-objects).
+  */
+  CHARSET_INFO *m_connection_cl;
+};
+
 /***************************************************************************
   Configuration parameters
 ****************************************************************************/
@@ -618,7 +698,9 @@ bool check_string_char_length(LEX_STRING *str, const char *err_msg,
                               uint max_char_length, CHARSET_INFO *cs,
                               bool no_error);
 
-bool parse_sql(THD *thd, class Lex_input_stream *lip);
+bool parse_sql(THD *thd,
+               class Lex_input_stream *lip,
+               class Object_creation_ctx *creation_ctx);
 
 enum enum_mysql_completiontype {
   ROLLBACK_RELEASE=-2, ROLLBACK=1,  ROLLBACK_AND_CHAIN=7,
@@ -2156,12 +2238,24 @@ bool schema_table_store_record(THD *thd, TABLE *table);
 int item_create_init();
 void item_create_cleanup();
 
+bool show_create_trigger(THD *thd, const sp_name *trg_name);
+
 inline void lex_string_set(LEX_STRING *lex_str, const char *c_str)
 {
   lex_str->str= (char *) c_str;
   lex_str->length= strlen(c_str);
 }
 
+bool load_charset(MEM_ROOT *mem_root,
+                  Field *field,
+                  CHARSET_INFO *dflt_cs,
+                  CHARSET_INFO **cs);
+
+bool load_collation(MEM_ROOT *mem_root,
+                    Field *field,
+                    CHARSET_INFO *dflt_cl,
+                    CHARSET_INFO **cl);
+
 #endif /* MYSQL_SERVER */
 #endif /* MYSQL_CLIENT */