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".

event/filter/eth_filter.go

@@ -1,127 +0,0 @@
-// Copyright 2014 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// 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
-
-import (
-	"sync"
-
-	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/state"
-	"github.com/ethereum/go-ethereum/event"
-)
-
-type FilterManager struct {
-	eventMux *event.TypeMux
-
-	filterMu sync.RWMutex
-	filterId int
-	filters  map[int]*core.Filter
-
-	quit chan struct{}
-}
-
-func NewFilterManager(mux *event.TypeMux) *FilterManager {
-	return &FilterManager{
-		eventMux: mux,
-		filters:  make(map[int]*core.Filter),
-	}
-}
-
-func (self *FilterManager) Start() {
-	go self.filterLoop()
-}
-
-func (self *FilterManager) Stop() {
-	close(self.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++
-
-	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)
-	}
-}
-
-// 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]
-}
-
-func (self *FilterManager) filterLoop() {
-	// Subscribe to events
-	events := self.eventMux.Subscribe(
-		//core.PendingBlockEvent{},
-		core.ChainEvent{},
-		core.TxPreEvent{},
-		state.Logs(nil))
-
-out:
-	for {
-		select {
-		case <-self.quit:
-			break out
-		case event := <-events.Chan():
-			switch event := event.(type) {
-			case core.ChainEvent:
-				self.filterMu.RLock()
-				for _, filter := range self.filters {
-					if filter.BlockCallback != nil {
-						filter.BlockCallback(event.Block, event.Logs)
-					}
-				}
-				self.filterMu.RUnlock()
-
-			case core.TxPreEvent:
-				self.filterMu.RLock()
-				for _, filter := range self.filters {
-					if filter.TransactionCallback != nil {
-						filter.TransactionCallback(event.Tx)
-					}
-				}
-				self.filterMu.RUnlock()
-
-			case state.Logs:
-				self.filterMu.RLock()
-				for _, filter := range self.filters {
-					if filter.LogsCallback != nil {
-						msgs := filter.FilterLogs(event)
-						if len(msgs) > 0 {
-							filter.LogsCallback(msgs)
-						}
-					}
-				}
-				self.filterMu.RUnlock()
-			}
-		}
-	}
-}