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/*
Copyright (C) 2005 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifndef INJECTOR_H
#define INJECTOR_H
/* Pull in 'byte', 'my_off_t', and 'uint32' */
#include <my_global.h>
#ifdef HAVE_ROW_BASED_REPLICATION
#include <my_bitmap.h>
/* Forward declarations */
class handler;
class MYSQL_LOG;
class st_table;
typedef st_table TABLE;
/*
Injector to inject rows into the MySQL server.
The injector class is used to notify the MySQL server of new rows that have
appeared outside of MySQL control.
The original purpose of this is to allow clusters---which handle replication
inside the cluster through other means---to insert new rows into binary log.
Note, however, that the injector should be used whenever rows are altered in
any manner that is outside of MySQL server visibility and which therefore
are not seen by the MySQL server.
*/
class injector
{
public:
/*
Get an instance of the injector.
DESCRIPTION
The injector is a Singleton, so this static function return the
available instance of the injector.
RETURN VALUE
A pointer to the available injector object.
*/
static injector *instance();
/*
A transaction where rows can be added.
DESCRIPTION
The transaction class satisfy the **CopyConstructible** and
**Assignable** requirements. Note that the transaction is *not*
default constructible.
*/
class transaction {
friend class injector;
public:
/* Convenience definitions */
typedef byte* record_type;
typedef uint32 server_id_type;
/*
Table reference.
RESPONSIBILITY
The class contains constructors to handle several forms of
references to tables. The constructors can implicitly be used to
construct references from, e.g., strings containing table names.
EXAMPLE
The class is intended to be used *by value*. Please, do not try to
construct objects of this type using 'new'; instead construct an
object, possibly a temporary object. For example:
injector::transaction::table tbl(share->table, true);
MY_BITMAP cols;
bitmap_init(&cols, NULL, (i + 7) / 8, false);
inj->write_row(::server_id, tbl, &cols, row_data);
or
MY_BITMAP cols;
bitmap_init(&cols, NULL, (i + 7) / 8, false);
inj->write_row(::server_id,
injector::transaction::table(share->table, true),
&cols, row_data);
This will work, be more efficient, and have greater chance of
inlining, not run the risk of losing pointers.
COLLABORATION
injector::transaction
Provide a flexible interface to the representation of tables.
*/
class table
{
public:
table(TABLE *table, bool is_transactional)
: m_table(table), m_is_transactional(is_transactional)
{
}
char const *db_name() const { return m_table->s->db.str; }
char const *table_name() const { return m_table->s->table_name.str; }
TABLE *get_table() const { return m_table; }
bool is_transactional() const { return m_is_transactional; }
private:
TABLE *m_table;
bool m_is_transactional;
};
/*
Binlog position as a structure.
*/
class binlog_pos {
friend class transaction;
public:
char const *file_name() const { return m_file_name; }
my_off_t file_pos() const { return m_file_pos; }
private:
char const *m_file_name;
my_off_t m_file_pos;
};
transaction() : m_thd(NULL) { }
transaction(transaction const&);
~transaction();
/* Clear transaction, i.e., make calls to 'good()' return false. */
void clear() { m_thd= NULL; }
/* Is the transaction in a good state? */
bool good() const { return m_thd != NULL; }
/* Default assignment operator: standard implementation */
transaction& operator=(transaction t) {
swap(t);
return *this;
}
/*
Add a 'write row' entry to the transaction.
*/
int write_row (server_id_type sid, table tbl,
MY_BITMAP const *cols, size_t colcnt,
record_type record);
/*
Add a 'delete row' entry to the transaction.
*/
int delete_row(server_id_type sid, table tbl,
MY_BITMAP const *cols, size_t colcnt,
record_type record);
/*
Add an 'update row' entry to the transaction.
*/
int update_row(server_id_type sid, table tbl,
MY_BITMAP const *cols, size_t colcnt,
record_type before, record_type after);
/*
Commit a transaction.
This member function will clean up after a sequence of *_row calls by,
for example, releasing resource and unlocking files.
*/
int commit();
/*
Get the position for the start of the transaction.
Returns the position in the binary log of the first event in this
transaction. If no event is yet written, the position where the event
*will* be written is returned. This position is known, since a
new_transaction() will lock the binary log and prevent any other
writes to the binary log.
*/
binlog_pos start_pos() const;
private:
/* Only the injector may construct these object */
transaction(MYSQL_LOG *, THD *);
void swap(transaction& o) {
/* std::swap(m_start_pos, o.m_start_pos); */
{
binlog_pos const tmp= m_start_pos;
m_start_pos= o.m_start_pos;
o.m_start_pos= tmp;
}
/* std::swap(m_thd, o.m_thd); */
{
THD* const tmp= m_thd;
m_thd= o.m_thd;
o.m_thd= tmp;
}
}
binlog_pos m_start_pos;
THD *m_thd;
};
/*
Create a new transaction. This member function will prepare for a
sequence of *_row calls by, for example, reserving resources and
locking files. There are two overloaded alternatives: one returning a
transaction by value and one using placement semantics. The following
two calls are equivalent, with the exception that the latter will
overwrite the transaction.
injector::transaction trans1= inj->new_trans(thd);
injector::transaction trans2;
inj->new_trans(thd, &trans);
*/
transaction new_trans(THD *);
void new_trans(THD *, transaction *);
private:
explicit injector();
~injector() { } /* Nothing needs to be done */
injector(injector const&); /* You're not allowed to copy injector
instances.
*/
};
#endif /* HAVE_ROW_BASED_REPLICATION */
#endif /* INJECTOR_H */
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