core, event/filter, xeth: refactored filter system

Moved the filtering system from `event` to `eth/filters` package and
removed the `core.Filter` object. The `filters.Filter` object now
requires a `common.Database` rather than a `eth.Backend` and invokes the
`core.GetBlockByX` directly rather than thru a "manager".

core/filter.go → eth/filters/filter.go

@@ -14,16 +14,15 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-package core
+package filters
 
 import (
 	"math"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/logger"
-	"github.com/ethereum/go-ethereum/logger/glog"
 )
 
 type AccountChange struct {
@@ -32,7 +31,7 @@ type AccountChange struct {
 
 // Filtering interface
 type Filter struct {
-	eth      Backend
+	db       common.Database
 	earliest int64
 	latest   int64
 	skip     int
@@ -47,8 +46,8 @@ type Filter struct {
 
 // 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}
+func New(db common.Database) *Filter {
+	return &Filter{db: db}
 }
 
 // Set the earliest and latest block for filtering.
@@ -80,7 +79,7 @@ func (self *Filter) SetSkip(skip int) {
 
 // Run filters logs with the current parameters set
 func (self *Filter) Find() state.Logs {
-	earliestBlock := self.eth.ChainManager().CurrentBlock()
+	earliestBlock := core.GetCurrentBlock(self.db)
 	var earliestBlockNo uint64 = uint64(self.earliest)
 	if self.earliest == -1 {
 		earliestBlockNo = earliestBlock.NumberU64()
@@ -92,7 +91,7 @@ func (self *Filter) Find() state.Logs {
 
 	var (
 		logs  state.Logs
-		block = self.eth.ChainManager().GetBlockByNumber(latestBlockNo)
+		block = core.GetBlockByNumber(self.db, latestBlockNo)
 	)
 
 done:
@@ -111,17 +110,17 @@ done:
 		// current parameters
 		if self.bloomFilter(block) {
 			// Get the logs of the block
-			unfiltered, err := self.eth.BlockProcessor().GetLogs(block)
-			if err != nil {
-				glog.V(logger.Warn).Infoln("err: filter get logs ", err)
-
-				break
+			var (
+				receipts   = core.GetBlockReceipts(self.db, block.Hash())
+				unfiltered state.Logs
+			)
+			for _, receipt := range receipts {
+				unfiltered = append(unfiltered, receipt.Logs()...)
 			}
-
 			logs = append(logs, self.FilterLogs(unfiltered)...)
 		}
 
-		block = self.eth.ChainManager().GetBlock(block.ParentHash())
+		block = core.GetBlockByHash(self.db, block.ParentHash())
 	}
 
 	skip := int(math.Min(float64(len(logs)), float64(self.skip)))

event/filter/eth_filter.go → eth/filters/filter_system.go

@@ -14,9 +14,9 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-package filter
-
-// TODO make use of the generic filtering system
+// package filters implements an ethereum filtering system for block,
+// transactions and log events.
+package filters
 
 import (
 	"sync"
@@ -26,60 +26,66 @@ import (
 	"github.com/ethereum/go-ethereum/event"
 )
 
-type FilterManager struct {
+// FilterSystem manages filters that filter specific events such as
+// block, transaction and log events. The Filtering system can be used to listen
+// for specific LOG events fires by the EVM (Ethereum Virtual Machine).
+type FilterSystem struct {
 	eventMux *event.TypeMux
 
 	filterMu sync.RWMutex
 	filterId int
-	filters  map[int]*core.Filter
+	filters  map[int]*Filter
 
 	quit chan struct{}
 }
 
-func NewFilterManager(mux *event.TypeMux) *FilterManager {
-	return &FilterManager{
+// NewFilterSystem returns a newly allocated filter manager
+func NewFilterSystem(mux *event.TypeMux) *FilterSystem {
+	fs := &FilterSystem{
 		eventMux: mux,
-		filters:  make(map[int]*core.Filter),
+		filters:  make(map[int]*Filter),
 	}
+	go fs.filterLoop()
+	return fs
 }
 
-func (self *FilterManager) Start() {
-	go self.filterLoop()
-}
-
-func (self *FilterManager) Stop() {
-	close(self.quit)
+// Stop quits the filter loop required for polling events
+func (fs *FilterSystem) Stop() {
+	close(fs.quit)
 }
 
-func (self *FilterManager) InstallFilter(filter *core.Filter) (id int) {
-	self.filterMu.Lock()
-	defer self.filterMu.Unlock()
-	id = self.filterId
-	self.filters[id] = filter
-	self.filterId++
+// Add adds a filter to the filter manager
+func (fs *FilterSystem) Add(filter *Filter) (id int) {
+	fs.filterMu.Lock()
+	defer fs.filterMu.Unlock()
+	id = fs.filterId
+	fs.filters[id] = filter
+	fs.filterId++
 
 	return id
 }
 
-func (self *FilterManager) UninstallFilter(id int) {
-	self.filterMu.Lock()
-	defer self.filterMu.Unlock()
-	if _, ok := self.filters[id]; ok {
-		delete(self.filters, id)
+// Remove removes a filter by filter id
+func (fs *FilterSystem) Remove(id int) {
+	fs.filterMu.Lock()
+	defer fs.filterMu.Unlock()
+	if _, ok := fs.filters[id]; ok {
+		delete(fs.filters, id)
 	}
 }
 
-// GetFilter retrieves a filter installed using InstallFilter.
-// The filter may not be modified.
-func (self *FilterManager) GetFilter(id int) *core.Filter {
-	self.filterMu.RLock()
-	defer self.filterMu.RUnlock()
-	return self.filters[id]
+// Get retrieves a filter installed using Add The filter may not be modified.
+func (fs *FilterSystem) Get(id int) *Filter {
+	fs.filterMu.RLock()
+	defer fs.filterMu.RUnlock()
+	return fs.filters[id]
 }
 
-func (self *FilterManager) filterLoop() {
+// filterLoop waits for specific events from ethereum and fires their handlers
+// when the filter matches the requirements.
+func (fs *FilterSystem) filterLoop() {
 	// Subscribe to events
-	events := self.eventMux.Subscribe(
+	events := fs.eventMux.Subscribe(
 		//core.PendingBlockEvent{},
 		core.ChainEvent{},
 		core.TxPreEvent{},
@@ -88,31 +94,31 @@ func (self *FilterManager) filterLoop() {
 out:
 	for {
 		select {
-		case <-self.quit:
+		case <-fs.quit:
 			break out
 		case event := <-events.Chan():
 			switch event := event.(type) {
 			case core.ChainEvent:
-				self.filterMu.RLock()
-				for _, filter := range self.filters {
+				fs.filterMu.RLock()
+				for _, filter := range fs.filters {
 					if filter.BlockCallback != nil {
 						filter.BlockCallback(event.Block, event.Logs)
 					}
 				}
-				self.filterMu.RUnlock()
+				fs.filterMu.RUnlock()
 
 			case core.TxPreEvent:
-				self.filterMu.RLock()
-				for _, filter := range self.filters {
+				fs.filterMu.RLock()
+				for _, filter := range fs.filters {
 					if filter.TransactionCallback != nil {
 						filter.TransactionCallback(event.Tx)
 					}
 				}
-				self.filterMu.RUnlock()
+				fs.filterMu.RUnlock()
 
 			case state.Logs:
-				self.filterMu.RLock()
-				for _, filter := range self.filters {
+				fs.filterMu.RLock()
+				for _, filter := range fs.filters {
 					if filter.LogsCallback != nil {
 						msgs := filter.FilterLogs(event)
 						if len(msgs) > 0 {
@@ -120,7 +126,7 @@ out:
 						}
 					}
 				}
-				self.filterMu.RUnlock()
+				fs.filterMu.RUnlock()
 			}
 		}
 	}

xeth/xeth.go

@@ -35,7 +35,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/eth"
-	"github.com/ethereum/go-ethereum/event/filter"
+	"github.com/ethereum/go-ethereum/eth/filters"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/miner"
@@ -75,7 +75,7 @@ type XEth struct {
 	whisper *Whisper
 
 	quit          chan struct{}
-	filterManager *filter.FilterManager
+	filterManager *filters.FilterSystem
 
 	logMu    sync.RWMutex
 	logQueue map[int]*logQueue
@@ -111,7 +111,7 @@ func New(ethereum *eth.Ethereum, frontend Frontend) *XEth {
 		backend:          ethereum,
 		frontend:         frontend,
 		quit:             make(chan struct{}),
-		filterManager:    filter.NewFilterManager(ethereum.EventMux()),
+		filterManager:    filters.NewFilterSystem(ethereum.EventMux()),
 		logQueue:         make(map[int]*logQueue),
 		blockQueue:       make(map[int]*hashQueue),
 		transactionQueue: make(map[int]*hashQueue),
@@ -128,7 +128,6 @@ func New(ethereum *eth.Ethereum, frontend Frontend) *XEth {
 	xeth.state = NewState(xeth, xeth.backend.ChainManager().State())
 
 	go xeth.start()
-	go xeth.filterManager.Start()
 
 	return xeth
 }
@@ -142,7 +141,7 @@ done:
 			self.logMu.Lock()
 			for id, filter := range self.logQueue {
 				if time.Since(filter.timeout) > filterTickerTime {
-					self.filterManager.UninstallFilter(id)
+					self.filterManager.Remove(id)
 					delete(self.logQueue, id)
 				}
 			}
@@ -151,7 +150,7 @@ done:
 			self.blockMu.Lock()
 			for id, filter := range self.blockQueue {
 				if time.Since(filter.timeout) > filterTickerTime {
-					self.filterManager.UninstallFilter(id)
+					self.filterManager.Remove(id)
 					delete(self.blockQueue, id)
 				}
 			}
@@ -160,7 +159,7 @@ done:
 			self.transactionMu.Lock()
 			for id, filter := range self.transactionQueue {
 				if time.Since(filter.timeout) > filterTickerTime {
-					self.filterManager.UninstallFilter(id)
+					self.filterManager.Remove(id)
 					delete(self.transactionQueue, id)
 				}
 			}
@@ -504,7 +503,7 @@ func (self *XEth) IsContract(address string) bool {
 }
 
 func (self *XEth) UninstallFilter(id int) bool {
-	defer self.filterManager.UninstallFilter(id)
+	defer self.filterManager.Remove(id)
 
 	if _, ok := self.logQueue[id]; ok {
 		self.logMu.Lock()
@@ -532,8 +531,8 @@ func (self *XEth) NewLogFilter(earliest, latest int64, skip, max int, address []
 	self.logMu.Lock()
 	defer self.logMu.Unlock()
 
-	filter := core.NewFilter(self.backend)
-	id := self.filterManager.InstallFilter(filter)
+	filter := filters.New(self.backend.ChainDb())
+	id := self.filterManager.Add(filter)
 	self.logQueue[id] = &logQueue{timeout: time.Now()}
 
 	filter.SetEarliestBlock(earliest)
@@ -558,8 +557,8 @@ func (self *XEth) NewTransactionFilter() int {
 	self.transactionMu.Lock()
 	defer self.transactionMu.Unlock()
 
-	filter := core.NewFilter(self.backend)
-	id := self.filterManager.InstallFilter(filter)
+	filter := filters.New(self.backend.ChainDb())
+	id := self.filterManager.Add(filter)
 	self.transactionQueue[id] = &hashQueue{timeout: time.Now()}
 
 	filter.TransactionCallback = func(tx *types.Transaction) {
@@ -577,8 +576,8 @@ func (self *XEth) NewBlockFilter() int {
 	self.blockMu.Lock()
 	defer self.blockMu.Unlock()
 
-	filter := core.NewFilter(self.backend)
-	id := self.filterManager.InstallFilter(filter)
+	filter := filters.New(self.backend.ChainDb())
+	id := self.filterManager.Add(filter)
 	self.blockQueue[id] = &hashQueue{timeout: time.Now()}
 
 	filter.BlockCallback = func(block *types.Block, logs state.Logs) {
@@ -635,7 +634,7 @@ func (self *XEth) TransactionFilterChanged(id int) []common.Hash {
 }
 
 func (self *XEth) Logs(id int) state.Logs {
-	filter := self.filterManager.GetFilter(id)
+	filter := self.filterManager.Get(id)
 	if filter != nil {
 		return filter.Find()
 	}
@@ -644,7 +643,7 @@ func (self *XEth) Logs(id int) state.Logs {
 }
 
 func (self *XEth) AllLogs(earliest, latest int64, skip, max int, address []string, topics [][]string) state.Logs {
-	filter := core.NewFilter(self.backend)
+	filter := filters.New(self.backend.ChainDb())
 	filter.SetEarliestBlock(earliest)
 	filter.SetLatestBlock(latest)
 	filter.SetSkip(skip)