# Mimic the sqlite3 console shell's .dump command
# Author: Paul Kippes <kippesp@gmail.com>

def _iterdump(connection):
 """
 Returns an iterator to the dump of the database in an SQL text format.

 Used to produce an SQL dump of the database. Useful to save an in-memory
 database for later restoration. This function should not be called
 directly but instead called from the Connection method, iterdump().
 """

 cu = connection.cursor()
 yield('BEGIN TRANSACTION;')

 # sqlite_master table contains the SQL CREATE statements for the database.
 q = """
 SELECT name, type, sql
 FROM sqlite_master
 WHERE sql NOT NULL AND
 type == 'table'
 """
 schema_res = cu.execute(q)
 for table_name, type, sql in schema_res.fetchall():
 if table_name == 'sqlite_sequence':
 yield('DELETE FROM sqlite_sequence;')
 elif table_name == 'sqlite_stat1':
 yield('ANALYZE sqlite_master;')
 elif table_name.startswith('sqlite_'):
 continue
 # NOTE: Virtual table support not implemented
 #elif sql.startswith('CREATE VIRTUAL TABLE'):
 # qtable = table_name.replace("'", "''")
 # yield("INSERT INTO sqlite_master(type,name,tbl_name,rootpage,sql)"\
 # "VALUES('table','%s','%s',0,'%s');" %
 # qtable,
 # qtable,
 # sql.replace("''"))
 else:
 yield('%s;' % sql)

 # Build the insert statement for each row of the current table
 res = cu.execute("PRAGMA table_info('%s')" % table_name)
 column_names = [str(table_info[1]) for table_info in res.fetchall()]
 q = "SELECT 'INSERT INTO \"%(tbl_name)s\" VALUES("
 q += ",".join(["'||quote(" + col + ")||'" for col in column_names])
 q += ")' FROM '%(tbl_name)s'"
 query_res = cu.execute(q % {'tbl_name': table_name})
 for row in query_res:
 yield("%s;" % row[0])

 # Now when the type is 'index', 'trigger', or 'view'
 q = """
 SELECT name, type, sql
 FROM sqlite_master
 WHERE sql NOT NULL AND
 type IN ('index', 'trigger', 'view')
 """
 schema_res = cu.execute(q)
 for name, type, sql in schema_res.fetchall():
 yield('%s;' % sql)

 yield('COMMIT;')