/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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#include "postgres.h"
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#include "funcapi.h"
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#include <unistd.h>
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#include "utils/age_session_info.h"
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#include "pg_fix.h"
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/*
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* static/global session info variables for use with the driver interface.
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*/
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static int session_info_pid = -1;
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static char *session_info_graph_name = NULL;
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static char *session_info_cypher_statement = NULL;
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static bool session_info_prepared = false;
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static void set_session_info(char *graph_name, char *cypher_statement);
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/* function to set the session info. it will clean it, if necessary. */
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static void set_session_info(char *graph_name, char *cypher_statement)
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{
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MemoryContext oldctx = NULL;
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if (is_session_info_prepared())
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{
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reset_session_info();
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}
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/* we need to use a higher memory context for the data pointed to. */
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oldctx = MemoryContextSwitchTo(TopMemoryContext);
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if (graph_name != NULL)
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{
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session_info_graph_name = pstrdup(graph_name);
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}
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else
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{
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session_info_graph_name = NULL;
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}
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if (cypher_statement != NULL)
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{
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session_info_cypher_statement = pstrdup(cypher_statement);
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}
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else
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{
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session_info_cypher_statement = NULL;
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}
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/* switch back to the original context */
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MemoryContextSwitchTo(oldctx);
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session_info_pid = _getpid();
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session_info_prepared = true;
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}
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/*
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* Helper function to return the value of session_info_cypher_statement or NULL
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* if the value isn't set. The value returned is a copy, so please free it when
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* done.
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*/
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char *get_session_info_graph_name(void)
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{
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if (is_session_info_prepared() &&
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session_info_graph_name != NULL)
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{
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return pstrdup(session_info_graph_name);
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}
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return NULL;
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}
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/*
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* Helper function to return the value of session_info_cypher_statement or NULL
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* if the value isn't set. The value returned is a copy, so please free it when
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* done.
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*/
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char *get_session_info_cypher_statement(void)
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{
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if (is_session_info_prepared() &&
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session_info_cypher_statement != NULL)
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{
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return pstrdup(session_info_cypher_statement);
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}
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return NULL;
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}
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/* function to return the state of the session info data */
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bool is_session_info_prepared(void)
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{
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/* is the session info prepared AND is the pid the same pid */
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if (session_info_prepared == true &&
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session_info_pid == _getpid())
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{
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return true;
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}
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return false;
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}
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/* function to clean and reset the session info back to default values */
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void reset_session_info(void)
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{
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/* if the session info is prepared, free the strings */
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if (session_info_prepared == true)
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{
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if (session_info_graph_name != NULL)
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{
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pfree(session_info_graph_name);
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}
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if (session_info_cypher_statement != NULL)
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{
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pfree(session_info_cypher_statement);
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}
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}
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/* reset the session info back to default unused values */
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session_info_graph_name = NULL;
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session_info_cypher_statement = NULL;
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session_info_prepared = false;
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session_info_pid = -1;
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}
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/* AGE SQL function to prepare session info */
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PG_FUNCTION_INFO_V1(age_prepare_cypher);
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Datum age_prepare_cypher(PG_FUNCTION_ARGS)
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{
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char *graph_name_str = NULL;
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char *cypher_statement_str = NULL;
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/* both arguments must be non-NULL */
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if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
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{
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PG_RETURN_BOOL(false);
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}
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graph_name_str = PG_GETARG_CSTRING(0);
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cypher_statement_str = PG_GETARG_CSTRING(1);
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/* both strings must be non-NULL */
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if (graph_name_str == NULL || cypher_statement_str == NULL)
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{
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PG_RETURN_BOOL(false);
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}
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set_session_info(graph_name_str, cypher_statement_str);
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PG_RETURN_BOOL(true);
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}
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