path: root/core/types/block.go

// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus-core library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus-core library. If not, see
// <http://www.gnu.org/licenses/>.

// TODO(jimmy-dexon): remove comments of NotaryAck before open source.

package types

import (
    "bytes"
    "fmt"
    "sync"
    "time"

    "github.com/dexon-foundation/dexon-consensus-core/common"
    "github.com/dexon-foundation/dexon-consensus-core/crypto"
)

var (
    // blockPool is the blocks cache to reuse allocated blocks.
    blockPool = sync.Pool{
        New: func() interface{} {
            return &Block{}
        },
    }
)

// RecycleBlock put unused block into cache, which might be reused if
// not garbage collected.
func RecycleBlock(b *Block) {
    blockPool.Put(b)
}

// NewBlock initiate a block.
func NewBlock() (b *Block) {
    b = blockPool.Get().(*Block)
    if b.Acks != nil {
        for k := range b.Acks {
            delete(b.Acks, k)
        }
    }
    if b.Timestamps != nil {
        for k := range b.Timestamps {
            delete(b.Timestamps, k)
        }
    }
    return
}

// Block represents a single event broadcasted on the network.
type Block struct {
    ProposerID ValidatorID               `json:"proposer_id"`
    ParentHash common.Hash               `json:"parent_hash"`
    Hash       common.Hash               `json:"hash"`
    ShardID    uint64                    `json:"shard_id"`
    ChainID    uint64                    `json:"chain_id"`
    Height     uint64                    `json:"height"`
    Timestamps map[ValidatorID]time.Time `json:"timestamps"`
    Acks       map[common.Hash]struct{}  `json:"acks"`
    Signature  crypto.Signature          `json:"signature"`

    CRSSignature crypto.Signature `json:"crs_signature"`

    Notary Notary `json:"notary"`
}

// Block implements BlockConverter interface.
func (b *Block) Block() *Block {
    return b
}

// Payloads impelmemnts BlockConverter interface.
func (b *Block) Payloads() [][]byte {
    return [][]byte{}
}

// SetBlock implments BlockConverter interface.
func (b *Block) SetBlock(block *Block) {
    *b = *block
}

// BlockConverter interface define the interface for extracting block
// information from an existing object.
type BlockConverter interface {
    Block() *Block
    Payloads() [][]byte
    SetBlock(block *Block)
}

func (b *Block) String() string {
    return fmt.Sprintf("Block(%v)", b.Hash.String()[:6])
}

// Clone returns a deep copy of a block.
func (b *Block) Clone() (bcopy *Block) {
    bcopy = NewBlock()
    bcopy.ProposerID = b.ProposerID
    bcopy.ParentHash = b.ParentHash
    bcopy.Hash = b.Hash
    bcopy.Height = b.Height
    bcopy.Signature = b.Signature.Clone()
    bcopy.CRSSignature = b.CRSSignature.Clone()
    bcopy.Notary.Timestamp = b.Notary.Timestamp
    bcopy.Notary.Height = b.Notary.Height
    if bcopy.Timestamps == nil {
        bcopy.Timestamps = make(
            map[ValidatorID]time.Time, len(b.Timestamps))
    }
    for k, v := range b.Timestamps {
        bcopy.Timestamps[k] = v
    }
    if bcopy.Acks == nil {
        bcopy.Acks = make(map[common.Hash]struct{}, len(b.Acks))
    }
    for k, v := range b.Acks {
        bcopy.Acks[k] = v
    }
    return
}

// IsGenesis checks if the block is a genesisBlock
func (b *Block) IsGenesis() bool {
    return b.Height == 0 && b.ParentHash == common.Hash{}
}

// ByHash is the helper type for sorting slice of blocks by hash.
type ByHash []*Block

func (b ByHash) Len() int {
    return len(b)
}

func (b ByHash) Less(i int, j int) bool {
    return bytes.Compare([]byte(b[i].Hash[:]), []byte(b[j].Hash[:])) == -1
}

func (b ByHash) Swap(i int, j int) {
    b[i], b[j] = b[j], b[i]
}

// ByHeight is the helper type for sorting slice of blocks by height.
type ByHeight []*Block

func (b ByHeight) Len() int {
    return len(b)
}

func (b ByHeight) Less(i int, j int) bool {
    return b[i].Height < b[j].Height
}

func (b ByHeight) Swap(i int, j int) {
    b[i], b[j] = b[j], b[i]
}