Coverage Report

Created: 2024-10-13 08:39

/Users/andrewlamb/Software/datafusion/datafusion/physical-plan/src/tree_node.rs
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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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//! This module provides common traits for visiting or rewriting tree nodes easily.
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use std::fmt::{self, Display, Formatter};
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use std::sync::Arc;
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use crate::{displayable, with_new_children_if_necessary, ExecutionPlan};
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use datafusion_common::tree_node::{ConcreteTreeNode, DynTreeNode};
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use datafusion_common::Result;
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impl DynTreeNode for dyn ExecutionPlan {
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    fn arc_children(&self) -> Vec<&Arc<Self>> {
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        self.children()
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    }
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    fn with_new_arc_children(
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        &self,
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        arc_self: Arc<Self>,
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        new_children: Vec<Arc<Self>>,
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    ) -> Result<Arc<Self>> {
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        with_new_children_if_necessary(arc_self, new_children)
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    }
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}
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/// A node object beneficial for writing optimizer rules, encapsulating an [`ExecutionPlan`] node with a payload.
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/// Since there are two ways to access child plans—directly from the plan and through child nodes—it's recommended
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/// to perform mutable operations via [`Self::update_plan_from_children`].
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#[derive(Debug)]
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pub struct PlanContext<T: Sized> {
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    /// The execution plan associated with this context.
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    pub plan: Arc<dyn ExecutionPlan>,
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    /// Custom data payload of the node.
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    pub data: T,
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    /// Child contexts of this node.
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    pub children: Vec<Self>,
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}
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impl<T> PlanContext<T> {
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    pub fn new(plan: Arc<dyn ExecutionPlan>, data: T, children: Vec<Self>) -> Self {
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        Self {
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            plan,
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            data,
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            children,
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        }
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    }
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    pub fn update_plan_from_children(mut self) -> Result<Self> {
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        let children_plans = self.children.iter().map(|c| Arc::clone(&c.plan)).collect();
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        self.plan = with_new_children_if_necessary(self.plan, children_plans)?;
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        Ok(self)
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    }
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}
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impl<T: Default> PlanContext<T> {
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    pub fn new_default(plan: Arc<dyn ExecutionPlan>) -> Self {
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        let children = plan
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            .children()
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            .into_iter()
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            .cloned()
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            .map(Self::new_default)
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            .collect();
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        Self::new(plan, Default::default(), children)
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    }
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}
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impl<T: Display> Display for PlanContext<T> {
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    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
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        let node_string = displayable(self.plan.as_ref()).one_line();
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        write!(f, "Node plan: {}", node_string)?;
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        write!(f, "Node data: {}", self.data)?;
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        write!(f, "")
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    }
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}
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impl<T> ConcreteTreeNode for PlanContext<T> {
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    fn children(&self) -> &[Self] {
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        &self.children
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    }
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    fn take_children(mut self) -> (Self, Vec<Self>) {
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        let children = std::mem::take(&mut self.children);
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        (self, children)
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    }
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    fn with_new_children(mut self, children: Vec<Self>) -> Result<Self> {
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        self.children = children;
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        self.update_plan_from_children()
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    }
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}