base.go

// Copyright (c) 2018 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package linear

import (
	"fmt"

	"github.com/m3db/m3/src/query/block"
	"github.com/m3db/m3/src/query/executor/transform"
	"github.com/m3db/m3/src/query/models"
	"github.com/m3db/m3/src/query/parser"
)

var emptyOp = BaseOp{}

// BaseOp stores required properties for logical operations.
type BaseOp struct {
	operatorType string
	processorFn  makeProcessor
}

func (o BaseOp) OpType() string {
	return o.operatorType
}

func (o BaseOp) String() string {
	return fmt.Sprintf("type: %s", o.OpType())
}

func (o BaseOp) Node(
	controller *transform.Controller,
	_ transform.Options,
) transform.OpNode {
	return &baseNode{
		controller: controller,
		op:         o,
		processor:  o.processorFn(o, controller),
	}
}

type baseNode struct {
	op         BaseOp
	controller *transform.Controller
	processor  Processor
}

func (c *baseNode) Params() parser.Params {
	return c.op
}

func (c *baseNode) Process(
	queryCtx *models.QueryContext,
	ID parser.NodeID,
	b block.Block,
) error {
	return transform.ProcessSimpleBlock(c, c.controller, queryCtx, ID, b)
}

func (c *baseNode) ProcessBlock(
	queryCtx *models.QueryContext,
	ID parser.NodeID,
	b block.Block,
) (block.Block, error) {
	stepIter, err := b.StepIter()
	if err != nil {
		return nil, err
	}

	builder, err := c.controller.BlockBuilder(queryCtx,
		b.Meta(), stepIter.SeriesMeta())
	if err != nil {
		return nil, err
	}

	if err := builder.AddCols(stepIter.StepCount()); err != nil {
		return nil, err
	}

	for index := 0; stepIter.Next(); index++ {
		step := stepIter.Current()
		values := c.processor.Process(step.Values())
		for _, value := range values {
			if err := builder.AppendValue(index, value); err != nil {
				return nil, err
			}
		}
	}

	if err = stepIter.Err(); err != nil {
		return nil, err
	}

	return builder.Build(), nil
}

func (c *baseNode) Meta(meta block.Metadata) block.Metadata {
	return meta
}

func (c *baseNode) SeriesMeta(metas []block.SeriesMeta) []block.SeriesMeta {
	return metas
}

// makeProcessor is a way to create a transform.
type makeProcessor func(op BaseOp, controller *transform.Controller) Processor

// Processor is implemented by the underlying transforms.
// todo: remove public visibility
type Processor interface {
	Process(values []float64) []float64
}