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##########################################################################
#
# pgAdmin 4 - PostgreSQL Tools
#
# Copyright (C) 2013 - 2024, The pgAdmin Development Team
# This software is released under the PostgreSQL Licence
#
##########################################################################
def _get_keyword(query):
"""
Calculate word len, used internally by is_begin_required
:param query: query
:return: keyword len, keyword
"""
query_len = len(query)
word_len = 0
while (word_len < query_len) and query[word_len].isalpha():
word_len += 1
keyword = query[0:word_len]
return word_len, keyword
def _check_next_keyword(query, word_len, keyword_list):
"""
Check if the next keyword is from the keyword list
:param query: query
:param word_len: current keyword len
:param keyword_list: next keyword list
:return: boolean
"""
if keyword_list is None:
return True
query_len = len(query)
query = query[word_len:query_len]
query = query.strip()
word_len, keyword = _get_keyword(query)
if keyword.lower() in keyword_list:
return False
return True
def is_begin_required(query):
"""Check if requires BEGIN in the current query."""
query = query.strip()
query_len = len(query)
# Check word length (since "beginx" is not "begin").
word_len, keyword = _get_keyword(query)
# Transaction control commands. These should include every keyword that
# gives rise to a TransactionStmt in the backend grammar, except for the
# savepoint-related commands.
#
# (We assume that START must be START TRANSACTION, since there is
# presently no other "START foo" command.)
# Commands not allowed within transactions. The statements checked for
# here should be exactly those that call PreventTransactionChain() in the
# backend.
if keyword.lower() in ["abort", "begin", "start", "commit", "vacuum",
"end", "rollback"]:
return False
if keyword.lower() == "cluster":
# CLUSTER with any arguments is allowed in transactions
query = query[word_len:query_len]
query = query.strip()
if query[0].isalpha():
return True # has additional words
return False # it's CLUSTER without arguments
if keyword.lower() == "create":
query = query[word_len:query_len]
query = query.strip()
query_len = len(query)
word_len, keyword = _get_keyword(query)
if keyword.lower() in ["database", "tablespace"]:
return False
# CREATE [UNIQUE] INDEX CONCURRENTLY isn't allowed in xacts
if keyword.lower() == "cluster":
query = query[word_len:query_len]
query = query.strip()
query_len = len(query)
word_len, keyword = _get_keyword(query)
if keyword.lower() == "index":
query = query[word_len:query_len]
query = query.strip()
word_len, keyword = _get_keyword(query)
if keyword.lower() == "concurrently":
return False
return True
next_keyword_map = {
# PREPARE TRANSACTION is a TC command, PREPARE foo is not
"prepare": ["transaction"],
# ALTER SYSTEM isn't allowed in xacts
"alter": ["system"],
# Note: these tests will match DROP SYSTEM and REINDEX TABLESPACE,
# which aren't really valid commands so we don't care much. The other
# four possible matches are correct.
"drop": ["database", "system", "tablespace"],
"reindex": ["database", "system", "tablespace"],
# DISCARD ALL isn't allowed in xacts, but other variants are allowed.
"discard": ["all"],
}
return _check_next_keyword(
query, word_len, next_keyword_map.get(keyword.lower(), None))