/*
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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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#ifndef AG_CYPHER_TRANSFORM_ENTITY_H
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#define AG_CYPHER_TRANSFORM_ENTITY_H
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#include "nodes/primnodes.h"
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#include "parser/parse_node.h"
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#include "nodes/cypher_nodes.h"
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#include "nodes/makefuncs.h"
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#include "parser/cypher_parse_node.h"
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enum transform_entity_type
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{
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ENT_VERTEX = 0x0,
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ENT_EDGE,
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ENT_VLE_EDGE,
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ENT_PATH
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};
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enum transform_entity_join_side
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{
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JOIN_SIDE_LEFT = 0x0,
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JOIN_SIDE_RIGHT
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};
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/*
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* In the transformation stage, we need to track
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* where a variable came from. When moving between
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* clauses, Postgres parsestate and Query data structures
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* are insufficient for some of the information we
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* need.
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*/
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typedef struct
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{
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// denotes whether this entity is a vertex or edge
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enum transform_entity_type type;
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/*
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* MATCH clauses are transformed into a select * FROM ... JOIN, etc
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* We need to know whether the table that this entity represents is
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* part of the join tree. If a cypher_node does not meet the conditions
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* set in INCLUDE_NODE_IN_JOIN_TREE. Then we can skip the node when
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* constructing our join tree. The entities around this particular entity
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* need to know this for the join to get properly constructed.
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*/
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bool in_join_tree;
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/*
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* The parse data structure will be transformed into an Expr that represents
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* the entity. When constructing the join tree, we need to know what it was
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* turned into. If the entity was originally created in a previous clause,
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* this will be a Var that we need to reference to extract the id, startid,
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* endid for the join. If the entity was created in the current clause, then
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* this will be a FuncExpr that we can reference to get the id, startid, and
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* endid.
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*/
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Expr *expr;
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/*
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* tells each clause whether this variable was
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* declared by itself or a previous clause.
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*/
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bool declared_in_current_clause;
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// The parse data structure that we transformed
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union
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{
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cypher_node *node;
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cypher_relationship *rel;
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cypher_path *path;
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} entity;
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} transform_entity;
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transform_entity *find_variable(cypher_parsestate *cpstate, char *name);
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transform_entity *find_transform_entity(cypher_parsestate *cpstate,
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char *name,
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enum transform_entity_type type);
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transform_entity *make_transform_entity(cypher_parsestate *cpstate,
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enum transform_entity_type type,
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Node *node, Expr *expr);
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char *get_entity_name(transform_entity *entity);
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Expr *get_relative_expr(transform_entity *entity, Index levelsup);
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#endif
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