1 files changed, 204 insertions, 0 deletions
diff --git a/core/filter.go b/core/filter.go
new file mode 100644
index 000000000..487e82902
--- /dev/null
+++ b/core/filter.go
@@ -0,0 +1,204 @@
+package core
+
+import (
+	"bytes"
+	"math"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/state"
+)
+
+type AccountChange struct {
+	Address, StateAddress []byte
+}
+
+type FilterOptions struct {
+	Earliest int64
+	Latest   int64
+
+	Address [][]byte
+	Topics  [][][]byte
+
+	Skip int
+	Max  int
+}
+
+// Filtering interface
+type Filter struct {
+	eth      Backend
+	earliest int64
+	latest   int64
+	skip     int
+	address  [][]byte
+	max      int
+	topics   [][][]byte
+
+	BlockCallback   func(*types.Block, state.Logs)
+	PendingCallback func(*types.Block, state.Logs)
+	LogsCallback    func(state.Logs)
+}
+
+// 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 Backend) *Filter {
+	return &Filter{eth: eth}
+}
+
+// SetOptions copies the filter options to the filter it self. The reason for this "silly" copy
+// is simply because named arguments in this case is extremely nice and readable.
+func (self *Filter) SetOptions(options FilterOptions) {
+	self.earliest = options.Earliest
+	self.latest = options.Latest
+	self.skip = options.Skip
+	self.max = options.Max
+	self.address = options.Address
+	self.topics = options.Topics
+
+}
+
+// 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) SetAddress(addr [][]byte) {
+	self.address = addr
+}
+
+func (self *Filter) SetTopics(topics [][][]byte) {
+	self.topics = topics
+}
+
+func (self *Filter) SetMax(max int) {
+	self.max = max
+}
+
+func (self *Filter) SetSkip(skip int) {
+	self.skip = skip
+}
+
+// Run filters logs with the current parameters set
+func (self *Filter) Find() state.Logs {
+	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 (
+		logs  state.Logs
+		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(logs):
+			break
+		}
+
+		// Use bloom filtering to see if this block is interesting given the
+		// current parameters
+		if self.bloomFilter(block) {
+			// Get the logs of the block
+			unfiltered, err := self.eth.BlockProcessor().GetLogs(block)
+			if err != nil {
+				chainlogger.Warnln("err: filter get logs ", err)
+
+				break
+			}
+
+			logs = append(logs, self.FilterLogs(unfiltered)...)
+		}
+
+		block = self.eth.ChainManager().GetBlock(block.ParentHash())
+	}
+
+	skip := int(math.Min(float64(len(logs)), float64(self.skip)))
+
+	return logs[skip:]
+}
+
+func includes(addresses [][]byte, a []byte) bool {
+	for _, addr := range addresses {
+		if !bytes.Equal(addr, a) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (self *Filter) FilterLogs(logs state.Logs) state.Logs {
+	var ret state.Logs
+
+	// Filter the logs for interesting stuff
+Logs:
+	for _, log := range logs {
+		if len(self.address) > 0 && !includes(self.address, log.Address()) {
+			continue
+		}
+
+		logTopics := make([][]byte, len(self.topics))
+		copy(logTopics, log.Topics())
+
+		for i, topics := range self.topics {
+			for _, topic := range topics {
+				var match bool
+				if bytes.Equal(log.Topics()[i], topic) {
+					match = true
+				}
+				if !match {
+					continue Logs
+				}
+			}
+		}
+
+		ret = append(ret, log)
+	}
+
+	return ret
+}
+
+func (self *Filter) bloomFilter(block *types.Block) bool {
+	if len(self.address) > 0 {
+		var included bool
+		for _, addr := range self.address {
+			if types.BloomLookup(block.Bloom(), addr) {
+				included = true
+				break
+			}
+		}
+
+		if !included {
+			return false
+		}
+	}
+
+	for _, sub := range self.topics {
+		var included bool
+		for _, topic := range sub {
+			if types.BloomLookup(block.Bloom(), topic) {
+				included = true
+				break
+			}
+		}
+		if !included {
+			return false
+		}
+	}
+
+	return true
+}