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- // Copyright 2015 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 trie
- import (
- "errors"
- "fmt"
- "github.com/ethereum/go-ethereum/common"
- "github.com/ethereum/go-ethereum/ethdb"
- "gopkg.in/karalabe/cookiejar.v2/collections/prque"
- )
- // ErrNotRequested is returned by the trie sync when it's requested to process a
- // node it did not request.
- var ErrNotRequested = errors.New("not requested")
- // ErrAlreadyProcessed is returned by the trie sync when it's requested to process a
- // node it already processed previously.
- var ErrAlreadyProcessed = errors.New("already processed")
- // request represents a scheduled or already in-flight state retrieval request.
- type request struct {
- hash common.Hash // Hash of the node data content to retrieve
- data []byte // Data content of the node, cached until all subtrees complete
- raw bool // Whether this is a raw entry (code) or a trie node
- parents []*request // Parent state nodes referencing this entry (notify all upon completion)
- depth int // Depth level within the trie the node is located to prioritise DFS
- deps int // Number of dependencies before allowed to commit this node
- callback LeafCallback // Callback to invoke if a leaf node it reached on this branch
- }
- // SyncResult is a simple list to return missing nodes along with their request
- // hashes.
- type SyncResult struct {
- Hash common.Hash // Hash of the originally unknown trie node
- Data []byte // Data content of the retrieved node
- }
- // syncMemBatch is an in-memory buffer of successfully downloaded but not yet
- // persisted data items.
- type syncMemBatch struct {
- batch map[common.Hash][]byte // In-memory membatch of recently completed items
- order []common.Hash // Order of completion to prevent out-of-order data loss
- }
- // newSyncMemBatch allocates a new memory-buffer for not-yet persisted trie nodes.
- func newSyncMemBatch() *syncMemBatch {
- return &syncMemBatch{
- batch: make(map[common.Hash][]byte),
- order: make([]common.Hash, 0, 256),
- }
- }
- // Sync is the main state trie synchronisation scheduler, which provides yet
- // unknown trie hashes to retrieve, accepts node data associated with said hashes
- // and reconstructs the trie step by step until all is done.
- type Sync struct {
- database DatabaseReader // Persistent database to check for existing entries
- membatch *syncMemBatch // Memory buffer to avoid frequest database writes
- requests map[common.Hash]*request // Pending requests pertaining to a key hash
- queue *prque.Prque // Priority queue with the pending requests
- }
- // NewSync creates a new trie data download scheduler.
- func NewSync(root common.Hash, database DatabaseReader, callback LeafCallback) *Sync {
- ts := &Sync{
- database: database,
- membatch: newSyncMemBatch(),
- requests: make(map[common.Hash]*request),
- queue: prque.New(),
- }
- ts.AddSubTrie(root, 0, common.Hash{}, callback)
- return ts
- }
- // AddSubTrie registers a new trie to the sync code, rooted at the designated parent.
- func (s *Sync) AddSubTrie(root common.Hash, depth int, parent common.Hash, callback LeafCallback) {
- // Short circuit if the trie is empty or already known
- if root == emptyRoot {
- return
- }
- if _, ok := s.membatch.batch[root]; ok {
- return
- }
- key := root.Bytes()
- blob, _ := s.database.Get(key)
- if local, err := decodeNode(key, blob, 0); local != nil && err == nil {
- return
- }
- // Assemble the new sub-trie sync request
- req := &request{
- hash: root,
- depth: depth,
- callback: callback,
- }
- // If this sub-trie has a designated parent, link them together
- if parent != (common.Hash{}) {
- ancestor := s.requests[parent]
- if ancestor == nil {
- panic(fmt.Sprintf("sub-trie ancestor not found: %x", parent))
- }
- ancestor.deps++
- req.parents = append(req.parents, ancestor)
- }
- s.schedule(req)
- }
- // AddRawEntry schedules the direct retrieval of a state entry that should not be
- // interpreted as a trie node, but rather accepted and stored into the database
- // as is. This method's goal is to support misc state metadata retrievals (e.g.
- // contract code).
- func (s *Sync) AddRawEntry(hash common.Hash, depth int, parent common.Hash) {
- // Short circuit if the entry is empty or already known
- if hash == emptyState {
- return
- }
- if _, ok := s.membatch.batch[hash]; ok {
- return
- }
- if ok, _ := s.database.Has(hash.Bytes()); ok {
- return
- }
- // Assemble the new sub-trie sync request
- req := &request{
- hash: hash,
- raw: true,
- depth: depth,
- }
- // If this sub-trie has a designated parent, link them together
- if parent != (common.Hash{}) {
- ancestor := s.requests[parent]
- if ancestor == nil {
- panic(fmt.Sprintf("raw-entry ancestor not found: %x", parent))
- }
- ancestor.deps++
- req.parents = append(req.parents, ancestor)
- }
- s.schedule(req)
- }
- // Missing retrieves the known missing nodes from the trie for retrieval.
- func (s *Sync) Missing(max int) []common.Hash {
- requests := []common.Hash{}
- for !s.queue.Empty() && (max == 0 || len(requests) < max) {
- requests = append(requests, s.queue.PopItem().(common.Hash))
- }
- return requests
- }
- // Process injects a batch of retrieved trie nodes data, returning if something
- // was committed to the database and also the index of an entry if processing of
- // it failed.
- func (s *Sync) Process(results []SyncResult) (bool, int, error) {
- committed := false
- for i, item := range results {
- // If the item was not requested, bail out
- request := s.requests[item.Hash]
- if request == nil {
- return committed, i, ErrNotRequested
- }
- if request.data != nil {
- return committed, i, ErrAlreadyProcessed
- }
- // If the item is a raw entry request, commit directly
- if request.raw {
- request.data = item.Data
- s.commit(request)
- committed = true
- continue
- }
- // Decode the node data content and update the request
- node, err := decodeNode(item.Hash[:], item.Data, 0)
- if err != nil {
- return committed, i, err
- }
- request.data = item.Data
- // Create and schedule a request for all the children nodes
- requests, err := s.children(request, node)
- if err != nil {
- return committed, i, err
- }
- if len(requests) == 0 && request.deps == 0 {
- s.commit(request)
- committed = true
- continue
- }
- request.deps += len(requests)
- for _, child := range requests {
- s.schedule(child)
- }
- }
- return committed, 0, nil
- }
- // Commit flushes the data stored in the internal membatch out to persistent
- // storage, returning the number of items written and any occurred error.
- func (s *Sync) Commit(dbw ethdb.Putter) (int, error) {
- // Dump the membatch into a database dbw
- for i, key := range s.membatch.order {
- if err := dbw.Put(key[:], s.membatch.batch[key]); err != nil {
- return i, err
- }
- }
- written := len(s.membatch.order)
- // Drop the membatch data and return
- s.membatch = newSyncMemBatch()
- return written, nil
- }
- // Pending returns the number of state entries currently pending for download.
- func (s *Sync) Pending() int {
- return len(s.requests)
- }
- // schedule inserts a new state retrieval request into the fetch queue. If there
- // is already a pending request for this node, the new request will be discarded
- // and only a parent reference added to the old one.
- func (s *Sync) schedule(req *request) {
- // If we're already requesting this node, add a new reference and stop
- if old, ok := s.requests[req.hash]; ok {
- old.parents = append(old.parents, req.parents...)
- return
- }
- // Schedule the request for future retrieval
- s.queue.Push(req.hash, float32(req.depth))
- s.requests[req.hash] = req
- }
- // children retrieves all the missing children of a state trie entry for future
- // retrieval scheduling.
- func (s *Sync) children(req *request, object node) ([]*request, error) {
- // Gather all the children of the node, irrelevant whether known or not
- type child struct {
- node node
- depth int
- }
- children := []child{}
- switch node := (object).(type) {
- case *shortNode:
- children = []child{{
- node: node.Val,
- depth: req.depth + len(node.Key),
- }}
- case *fullNode:
- for i := 0; i < 17; i++ {
- if node.Children[i] != nil {
- children = append(children, child{
- node: node.Children[i],
- depth: req.depth + 1,
- })
- }
- }
- default:
- panic(fmt.Sprintf("unknown node: %+v", node))
- }
- // Iterate over the children, and request all unknown ones
- requests := make([]*request, 0, len(children))
- for _, child := range children {
- // Notify any external watcher of a new key/value node
- if req.callback != nil {
- if node, ok := (child.node).(valueNode); ok {
- if err := req.callback(node, req.hash); err != nil {
- return nil, err
- }
- }
- }
- // If the child references another node, resolve or schedule
- if node, ok := (child.node).(hashNode); ok {
- // Try to resolve the node from the local database
- hash := common.BytesToHash(node)
- if _, ok := s.membatch.batch[hash]; ok {
- continue
- }
- if ok, _ := s.database.Has(node); ok {
- continue
- }
- // Locally unknown node, schedule for retrieval
- requests = append(requests, &request{
- hash: hash,
- parents: []*request{req},
- depth: child.depth,
- callback: req.callback,
- })
- }
- }
- return requests, nil
- }
- // commit finalizes a retrieval request and stores it into the membatch. If any
- // of the referencing parent requests complete due to this commit, they are also
- // committed themselves.
- func (s *Sync) commit(req *request) (err error) {
- // Write the node content to the membatch
- s.membatch.batch[req.hash] = req.data
- s.membatch.order = append(s.membatch.order, req.hash)
- delete(s.requests, req.hash)
- // Check all parents for completion
- for _, parent := range req.parents {
- parent.deps--
- if parent.deps == 0 {
- if err := s.commit(parent); err != nil {
- return err
- }
- }
- }
- return nil
- }
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