plugeth/triedb/pathdb/difflayer.go

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// Copyright 2022 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 pathdb
import (
"fmt"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/trie/trienode"
"github.com/ethereum/go-ethereum/trie/triestate"
)
// diffLayer represents a collection of modifications made to the in-memory tries
// along with associated state changes after running a block on top.
//
// The goal of a diff layer is to act as a journal, tracking recent modifications
// made to the state, that have not yet graduated into a semi-immutable state.
type diffLayer struct {
// Immutables
root common.Hash // Root hash to which this layer diff belongs to
id uint64 // Corresponding state id
block uint64 // Associated block number
nodes map[common.Hash]map[string]*trienode.Node // Cached trie nodes indexed by owner and path
states *triestate.Set // Associated state change set for building history
memory uint64 // Approximate guess as to how much memory we use
parent layer // Parent layer modified by this one, never nil, **can be changed**
lock sync.RWMutex // Lock used to protect parent
}
// newDiffLayer creates a new diff layer on top of an existing layer.
func newDiffLayer(parent layer, root common.Hash, id uint64, block uint64, nodes map[common.Hash]map[string]*trienode.Node, states *triestate.Set) *diffLayer {
var (
size int64
count int
)
dl := &diffLayer{
root: root,
id: id,
block: block,
nodes: nodes,
states: states,
parent: parent,
}
for _, subset := range nodes {
for path, n := range subset {
dl.memory += uint64(n.Size() + len(path))
size += int64(len(n.Blob) + len(path))
}
count += len(subset)
}
if states != nil {
dl.memory += uint64(states.Size())
}
dirtyWriteMeter.Mark(size)
diffLayerNodesMeter.Mark(int64(count))
diffLayerBytesMeter.Mark(int64(dl.memory))
log.Debug("Created new diff layer", "id", id, "block", block, "nodes", count, "size", common.StorageSize(dl.memory))
return dl
}
// rootHash implements the layer interface, returning the root hash of
// corresponding state.
func (dl *diffLayer) rootHash() common.Hash {
return dl.root
}
// stateID implements the layer interface, returning the state id of the layer.
func (dl *diffLayer) stateID() uint64 {
return dl.id
}
// parentLayer implements the layer interface, returning the subsequent
// layer of the diff layer.
func (dl *diffLayer) parentLayer() layer {
dl.lock.RLock()
defer dl.lock.RUnlock()
return dl.parent
}
// node retrieves the node with provided node information. It's the internal
// version of Node function with additional accessed layer tracked. No error
// will be returned if node is not found.
func (dl *diffLayer) node(owner common.Hash, path []byte, hash common.Hash, depth int) ([]byte, error) {
// Hold the lock, ensure the parent won't be changed during the
// state accessing.
dl.lock.RLock()
defer dl.lock.RUnlock()
// If the trie node is known locally, return it
subset, ok := dl.nodes[owner]
if ok {
n, ok := subset[string(path)]
if ok {
// If the trie node is not hash matched, or marked as removed,
// bubble up an error here. It shouldn't happen at all.
if n.Hash != hash {
dirtyFalseMeter.Mark(1)
log.Error("Unexpected trie node in diff layer", "owner", owner, "path", path, "expect", hash, "got", n.Hash)
return nil, newUnexpectedNodeError("diff", hash, n.Hash, owner, path, n.Blob)
}
dirtyHitMeter.Mark(1)
dirtyNodeHitDepthHist.Update(int64(depth))
dirtyReadMeter.Mark(int64(len(n.Blob)))
return n.Blob, nil
}
}
// Trie node unknown to this layer, resolve from parent
if diff, ok := dl.parent.(*diffLayer); ok {
return diff.node(owner, path, hash, depth+1)
}
// Failed to resolve through diff layers, fallback to disk layer
return dl.parent.Node(owner, path, hash)
}
// Node implements the layer interface, retrieving the trie node blob with the
// provided node information. No error will be returned if the node is not found.
func (dl *diffLayer) Node(owner common.Hash, path []byte, hash common.Hash) ([]byte, error) {
return dl.node(owner, path, hash, 0)
}
// update implements the layer interface, creating a new layer on top of the
// existing layer tree with the specified data items.
func (dl *diffLayer) update(root common.Hash, id uint64, block uint64, nodes map[common.Hash]map[string]*trienode.Node, states *triestate.Set) *diffLayer {
return newDiffLayer(dl, root, id, block, nodes, states)
}
// persist flushes the diff layer and all its parent layers to disk layer.
func (dl *diffLayer) persist(force bool) (layer, error) {
if parent, ok := dl.parentLayer().(*diffLayer); ok {
// Hold the lock to prevent any read operation until the new
// parent is linked correctly.
dl.lock.Lock()
// The merging of diff layers starts at the bottom-most layer,
// therefore we recurse down here, flattening on the way up
// (diffToDisk).
result, err := parent.persist(force)
if err != nil {
dl.lock.Unlock()
return nil, err
}
dl.parent = result
dl.lock.Unlock()
}
return diffToDisk(dl, force)
}
// diffToDisk merges a bottom-most diff into the persistent disk layer underneath
// it. The method will panic if called onto a non-bottom-most diff layer.
func diffToDisk(layer *diffLayer, force bool) (layer, error) {
disk, ok := layer.parentLayer().(*diskLayer)
if !ok {
panic(fmt.Sprintf("unknown layer type: %T", layer.parentLayer()))
}
return disk.commit(layer, force)
}