#

# Copyright (C) 2009-2020 the sqlparse authors and contributors

# <see AUTHORS file>

#

# This module is part of python-sqlparse and is released under

# the BSD License: https://opensource.org/licenses/BSD-3-Clause

"""filter"""

from sqlparse import filters

from sqlparse import lexer

from sqlparse.engine.statement_splitter import StatementSplitter

class FilterStack:

def __init__(self):

self.preprocess = []

self.stmtprocess = []

self.postprocess = []

self.grouping_filter = None

def enable_grouping(self):

if self.grouping_filter is None:

self.grouping_filter = filters.GroupingFilter(True)

self.stmtprocess.append(self.grouping_filter)

def run(self, sql, encoding=None):

stream = lexer.tokenize(sql, encoding)

# Process token stream

for filter_ in self.preprocess:

stream = filter_.process(stream)

stream = StatementSplitter().process(stream)

# Output: Stream processed Statements

for stmt in stream:

for filter_ in self.stmtprocess:

filter_.process(stmt)

for filter_ in self.postprocess:

stmt = filter_.process(stmt)

yield stmt