1 files changed, 206 insertions, 0 deletions
diff --git a/ethchain/filter.go b/ethchain/filter.go
new file mode 100644
index 000000000..4e7fe68a8
--- /dev/null
+++ b/ethchain/filter.go
@@ -0,0 +1,206 @@
+package ethchain
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+
+	"github.com/ethereum/go-ethereum/ethstate"
+)
+
+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(*Block)
+	MessageCallback func(ethstate.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() []*ethstate.Message {
+	var earliestBlockNo uint64 = uint64(self.earliest)
+	if self.earliest == -1 {
+		earliestBlockNo = self.eth.ChainManager().CurrentBlock.Number.Uint64()
+	}
+	var latestBlockNo uint64 = uint64(self.latest)
+	if self.latest == -1 {
+		latestBlockNo = self.eth.ChainManager().CurrentBlock.Number.Uint64()
+	}
+
+	var (
+		messages []*ethstate.Message
+		block    = self.eth.ChainManager().GetBlockByNumber(latestBlockNo)
+		quit     bool
+	)
+	for i := 0; !quit && block != nil; i++ {
+		// Quit on latest
+		switch {
+		case block.Number.Uint64() == earliestBlockNo:
+			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.StateManager().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.PrevHash)
+	}
+
+	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 []*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 _, 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 *Block) bool {
+	fk := append([]byte("bloom"), block.Hash()...)
+	bin, err := self.eth.Db().Get(fk)
+	if err != nil {
+		fmt.Println(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
+}