org.neo4j.cypher.internal.rewriting.rewriters.nameAllPatternElements.scala Maven / Gradle / Ivy

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Tree rewriting support, and AST rewriters for the Cypher query language
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/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [https://neo4j.com]
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.neo4j.cypher.internal.rewriting.rewriters

import org.neo4j.cypher.internal.ast.semantics.SemanticState
import org.neo4j.cypher.internal.expressions.NodePattern
import org.neo4j.cypher.internal.expressions.RelationshipPattern
import org.neo4j.cypher.internal.expressions.ShortestPathExpression
import org.neo4j.cypher.internal.expressions.Variable
import org.neo4j.cypher.internal.rewriting.conditions.SemanticInfoAvailable
import org.neo4j.cypher.internal.rewriting.conditions.noUnnamedNodesAndRelationships
import org.neo4j.cypher.internal.rewriting.rewriters.factories.ASTRewriterFactory
import org.neo4j.cypher.internal.util.AnonymousVariableNameGenerator
import org.neo4j.cypher.internal.util.CancellationChecker
import org.neo4j.cypher.internal.util.CypherExceptionFactory
import org.neo4j.cypher.internal.util.Rewriter
import org.neo4j.cypher.internal.util.StepSequencer
import org.neo4j.cypher.internal.util.bottomUp
import org.neo4j.cypher.internal.util.symbols.ParameterTypeInfo

case class nameAllPatternElements(anonymousVariableNameGenerator: AnonymousVariableNameGenerator) extends Rewriter {

  override def apply(that: AnyRef): AnyRef = namingRewriter.apply(that)

  private def namingRewriter: Rewriter = bottomUp(
    Rewriter.lift {
      case pattern: NodePattern if pattern.variable.isEmpty =>
        val syntheticName = anonymousVariableNameGenerator.nextName
        pattern.copy(variable = Some(Variable(syntheticName)(pattern.position, Variable.isIsolatedDefault)))(
          pattern.position
        )

      case pattern: RelationshipPattern if pattern.variable.isEmpty =>
        val syntheticName = anonymousVariableNameGenerator.nextName
        pattern.copy(variable = Some(Variable(syntheticName)(pattern.position, Variable.isIsolatedDefault)))(
          pattern.position
        )
    },
    stopper = {
      case _: ShortestPathExpression => true
      case _                         => false
    }
  )
}

case object nameAllPatternElements extends StepSequencer.Step with ASTRewriterFactory {

  override def getRewriter(
    semanticState: SemanticState,
    parameterTypeMapping: Map[String, ParameterTypeInfo],
    cypherExceptionFactory: CypherExceptionFactory,
    anonymousVariableNameGenerator: AnonymousVariableNameGenerator,
    cancellationChecker: CancellationChecker
  ): Rewriter = nameAllPatternElements(anonymousVariableNameGenerator)

  override def preConditions: Set[StepSequencer.Condition] = Set.empty

  override def postConditions: Set[StepSequencer.Condition] = Set(
    noUnnamedNodesAndRelationships
  )

  override def invalidatedConditions: Set[StepSequencer.Condition] = SemanticInfoAvailable
}