validator.go

// Copyright 2016-2018 Stratumn SAS. All rights reserved.
//
// 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 validators

import (
	"context"

	"github.com/stratumn/go-chainscript"
	"github.com/stratumn/go-core/store"
)

// Validator defines a validator that has an internal state, identified by
// its hash.
type Validator interface {
	// Validate runs validations on a link and returns an error
	// if the link is invalid.
	Validate(context.Context, store.SegmentReader, *chainscript.Link) error

	// ShouldValidate returns a boolean whether the link should be checked
	ShouldValidate(*chainscript.Link) bool

	// Hash returns the hash of the validator's state.
	// It can be used to know which set of validations were applied
	// to a block.
	Hash() ([]byte, error)
}

// Validators is an array of Validator.
type Validators []Validator

// ProcessesValidators maps a process name to a list of validators.
type ProcessesValidators map[string]Validators

// Flatten processes validators to a single slice.
func (pv ProcessesValidators) Flatten() Validators {
	var vs Validators
	for _, v := range pv {
		vs = append(vs, v...)
	}

	return vs
}