ekuiper-new/internal/topo/planner/watermark_plan.go

// Copyright 2023 EMQ Technologies Co., Ltd.
//
// 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 planner

import "github.com/lf-edge/ekuiper/pkg/ast"

type WatermarkPlan struct {
	baseLogicalPlan
	Emitters []string
}

func (p WatermarkPlan) Init() *WatermarkPlan {
	p.baseLogicalPlan.self = &p
	return &p
}

// PushDownPredicate Push down all the conditions to the data source.
// The condition here must be safe to push down or it will be catched by above planner, such as countWindow planner.
func (p *WatermarkPlan) PushDownPredicate(condition ast.Expr) (ast.Expr, LogicalPlan) {
	if len(p.children) == 0 {
		return condition, p.self
	}
	rest := condition
	for i, child := range p.children {
		if _, ok := child.(*DataSourcePlan); ok {
			var newChild LogicalPlan
			rest, newChild = child.PushDownPredicate(rest)
			p.children[i] = newChild
		}
	}
	return rest, p.self
}