path: root/ethchain/filter.go

package ethchain

import (
    "bytes"
    "fmt"

    "github.com/ethereum/eth-go/ethstate"
    "github.com/ethereum/eth-go/ethutil"
    "gopkg.in/qml.v1"
)

type data struct {
    id, address []byte
}

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

    altered []data
}

// 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 NewFilterFromMap(object map[string]interface{}, eth EthManager) *Filter {
    filter := NewFilter(eth)

    if object["earliest"] != nil {
        earliest := object["earliest"]
        if e, ok := earliest.(string); ok {
            filter.SetEarliestBlock(ethutil.Hex2Bytes(e))
        } else {
            filter.SetEarliestBlock(earliest)
        }
    }

    if object["latest"] != nil {
        latest := object["latest"]
        if l, ok := latest.(string); ok {
            filter.SetLatestBlock(ethutil.Hex2Bytes(l))
        } else {
            filter.SetLatestBlock(latest)
        }
    }

    if object["to"] != nil {
        filter.AddTo(ethutil.Hex2Bytes(object["to"].(string)))
    }

    if object["from"] != nil {
        filter.AddFrom(ethutil.Hex2Bytes(object["from"].(string)))
    }

    if object["max"] != nil {
        filter.SetMax(object["max"].(int))
    }

    if object["skip"] != nil {
        filter.SetSkip(object["skip"].(int))
    }

    if object["altered"] != nil {
        filter.altered = makeAltered(object["altered"])
    }

    return filter
}

func (self *Filter) AddAltered(id, address []byte) {
    self.altered = append(self.altered, data{id, address})
}

// 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 interface{}) {
    e := ethutil.NewValue(earliest)

    // Check for -1 (latest) otherwise assume bytes
    if e.Int() == -1 {
        self.earliest = self.eth.BlockChain().CurrentBlock.Hash()
    } else if e.Len() > 0 {
        self.earliest = e.Bytes()
    } else {
        panic(fmt.Sprintf("earliest has to be either -1 or a valid hash: %v (%T)", e, e.Val))
    }
}

func (self *Filter) SetLatestBlock(latest interface{}) {
    l := ethutil.NewValue(latest)

    // Check for -1 (latest) otherwise assume bytes
    if l.Int() == -1 {
        self.latest = self.eth.BlockChain().CurrentBlock.Hash()
    } else if l.Len() > 0 {
        self.latest = l.Bytes()
    } else {
        panic(fmt.Sprintf("latest has to be either -1 or a valid hash: %v", l))
    }
}

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() []*ethstate.Message {
    var messages []*ethstate.Message

    block := self.eth.BlockChain().GetBlock(self.latest)

    // skip N blocks (useful for pagination)
    if self.skip > 0 {
        for i := 0; i < i; i++ {
            block = self.eth.BlockChain().GetBlock(block.PrevHash)
        }
    }

    // Start block filtering
    quit := false
    for i := 1; !quit && block != nil; i++ {
        // Mark last check
        if self.max == i || (len(self.earliest) > 0 && bytes.Compare(block.Hash(), self.earliest) == 0) {
            quit = true
        }

        // 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.StateManager().GetMessages(block)
            if err != nil {
                chainlogger.Warnln("err: filter get messages ", err)

                break
            }

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

        block = self.eth.BlockChain().GetBlock(block.PrevHash)
    }

    return messages
}

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 []*ethstate.Message) []*ethstate.Message {
    var messages []*ethstate.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 _, item := range self.altered {
            if len(item.id) > 0 && bytes.Compare(message.To, item.id) != 0 {
                continue
            }

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

            match = true
            break
        }

        if !match {
            continue
        }

        messages = append(messages, message)
    }

    return messages
}

func (self *Filter) bloomFilter(block *Block) bool {
    fk := append([]byte("bloom"), block.Hash()...)
    bin, err := self.eth.Db().Get(fk)
    if err != nil {
        panic(err)
    }

    bloom := NewBloomFilter(bin)

    var fromIncluded, toIncluded bool
    if len(self.from) > 0 {
        for _, from := range self.from {
            if bloom.Search(from) {
                fromIncluded = true
                break
            }
        }
    } else {
        fromIncluded = true
    }

    if len(self.to) > 0 {
        for _, to := range self.to {
            if bloom.Search(to) {
                toIncluded = true
                break
            }
        }
    } else {
        toIncluded = true
    }

    return fromIncluded && toIncluded
}

// Conversion methodn
func mapToData(m map[string]interface{}) (d data) {
    if str, ok := m["id"].(string); ok {
        d.id = ethutil.Hex2Bytes(str)
    }

    if str, ok := m["at"].(string); ok {
        d.address = ethutil.Hex2Bytes(str)
    }

    return
}

// data can come in in the following formats:
// ["aabbccdd", {id: "ccddee", at: "11223344"}], "aabbcc", {id: "ccddee", at: "1122"}
func makeAltered(v interface{}) (d []data) {
    if str, ok := v.(string); ok {
        d = append(d, data{ethutil.Hex2Bytes(str), nil})
    } else if obj, ok := v.(map[string]interface{}); ok {
        d = append(d, mapToData(obj))
    } else if slice, ok := v.([]interface{}); ok {
        for _, item := range slice {
            d = append(d, makeAltered(item)...)
        }
    } else if qList, ok := v.(*qml.List); ok {
        var s []interface{}
        qList.Convert(&s)

        fmt.Println(s)

        d = makeAltered(s)
    } else if qMap, ok := v.(*qml.Map); ok {
        var m map[string]interface{}
        qMap.Convert(&m)
        fmt.Println(m)

        d = makeAltered(m)
    } else {
        panic(fmt.Sprintf("makeAltered err (unknown conversion): %T\n", v))
    }

    return
}