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path: root/ethchain/filter.go
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package ethchain

import (
    "bytes"
    "fmt"

    "github.com/ethereum/eth-go/ethstate"
    "github.com/ethereum/eth-go/ethutil"
)

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

// 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}
}

// 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) SetTo(addr []byte) {
    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
            }

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

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

                messages = append(messages, message)
            }
        }

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

    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)

    if len(self.from) > 0 {
        if !bloom.Search(self.from) {
            return false
        }
    }

    if len(self.to) > 0 {
        if !bloom.Search(self.to) {
            return false
        }
    }

    return true
}