path: root/core/filter.go

package core

import (
    "bytes"
    "math"
    "math/big"

    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/ethutil"
    "github.com/ethereum/go-ethereum/state"
)

type AccountChange struct {
    Address, StateAddress []byte
}

// Filtering interface
type Filter struct {
    eth      EthManager
    earliest int64
    latest   int64
    skip     int
    from, to [][]byte
    max      int

    Altered []AccountChange

    BlockCallback   func(*types.Block)
    MessageCallback func(state.Messages)
}

// Create a new filter which uses a bloom filter on blocks to figure out whether a particular block
// is interesting or not.
func NewFilter(eth EthManager) *Filter {
    return &Filter{eth: eth}
}

func (self *Filter) AddAltered(address, stateAddress []byte) {
    self.Altered = append(self.Altered, AccountChange{address, stateAddress})
}

// Set the earliest and latest block for filtering.
// -1 = latest block (i.e., the current block)
// hash = particular hash from-to
func (self *Filter) SetEarliestBlock(earliest int64) {
    self.earliest = earliest
}

func (self *Filter) SetLatestBlock(latest int64) {
    self.latest = latest
}

func (self *Filter) SetFrom(addr [][]byte) {
    self.from = addr
}

func (self *Filter) AddFrom(addr []byte) {
    self.from = append(self.from, addr)
}

func (self *Filter) SetTo(addr [][]byte) {
    self.to = addr
}

func (self *Filter) AddTo(addr []byte) {
    self.to = append(self.to, addr)
}

func (self *Filter) SetMax(max int) {
    self.max = max
}

func (self *Filter) SetSkip(skip int) {
    self.skip = skip
}

// Run filters messages with the current parameters set
func (self *Filter) Find() []*state.Message {
    earliestBlock := self.eth.ChainManager().CurrentBlock()
    var earliestBlockNo uint64 = uint64(self.earliest)
    if self.earliest == -1 {
        earliestBlockNo = earliestBlock.NumberU64()
    }
    var latestBlockNo uint64 = uint64(self.latest)
    if self.latest == -1 {
        latestBlockNo = earliestBlock.NumberU64()
    }

    var (
        messages []*state.Message
        block    = self.eth.ChainManager().GetBlockByNumber(latestBlockNo)
        quit     bool
    )
    for i := 0; !quit && block != nil; i++ {
        // Quit on latest
        switch {
        case block.NumberU64() == earliestBlockNo, block.NumberU64() == 0:
            quit = true
        case self.max <= len(messages):
            break
        }

        // Use bloom filtering to see if this block is interesting given the
        // current parameters
        if self.bloomFilter(block) {
            // Get the messages of the block
            msgs, err := self.eth.BlockProcessor().GetMessages(block)
            if err != nil {
                chainlogger.Warnln("err: filter get messages ", err)

                break
            }

            messages = append(messages, self.FilterMessages(msgs)...)
        }

        block = self.eth.ChainManager().GetBlock(block.ParentHash())
    }

    skip := int(math.Min(float64(len(messages)), float64(self.skip)))

    return messages[skip:]
}

func includes(addresses [][]byte, a []byte) (found bool) {
    for _, addr := range addresses {
        if bytes.Compare(addr, a) == 0 {
            return true
        }
    }

    return
}

func (self *Filter) FilterMessages(msgs []*state.Message) []*state.Message {
    var messages []*state.Message

    // Filter the messages for interesting stuff
    for _, message := range msgs {
        if len(self.to) > 0 && !includes(self.to, message.To) {
            continue
        }

        if len(self.from) > 0 && !includes(self.from, message.From) {
            continue
        }

        var match bool
        if len(self.Altered) == 0 {
            match = true
        }

        for _, accountChange := range self.Altered {
            if len(accountChange.Address) > 0 && bytes.Compare(message.To, accountChange.Address) != 0 {
                continue
            }

            if len(accountChange.StateAddress) > 0 && !includes(message.ChangedAddresses, accountChange.StateAddress) {
                continue
            }

            match = true
            break
        }

        if !match {
            continue
        }

        messages = append(messages, message)
    }

    return messages
}

func (self *Filter) bloomFilter(block *types.Block) bool {
    var fromIncluded, toIncluded bool
    if len(self.from) > 0 {
        for _, from := range self.from {
            if types.BloomLookup(block.Bloom(), from) || bytes.Equal(block.Coinbase(), from) {
                fromIncluded = true
                break
            }
        }
    } else {
        fromIncluded = true
    }

    if len(self.to) > 0 {
        for _, to := range self.to {
            if types.BloomLookup(block.Bloom(), ethutil.U256(new(big.Int).Add(ethutil.Big1, ethutil.BigD(to))).Bytes()) || bytes.Equal(block.Coinbase(), to) {
                toIncluded = true
                break
            }
        }
    } else {
        toIncluded = true
    }

    return fromIncluded && toIncluded
}