342 lines
8.7 KiB
Go
342 lines
8.7 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package api
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"sync"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/logger"
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"github.com/ethereum/go-ethereum/logger/glog"
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"github.com/ethereum/go-ethereum/swarm/storage"
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)
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const (
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manifestType = "application/bzz-manifest+json"
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)
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type manifestTrie struct {
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dpa *storage.DPA
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entries [257]*manifestTrieEntry // indexed by first character of path, entries[256] is the empty path entry
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hash storage.Key // if hash != nil, it is stored
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}
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type manifestJSON struct {
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Entries []*manifestTrieEntry `json:"entries"`
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}
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type manifestTrieEntry struct {
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Path string `json:"path"`
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Hash string `json:"hash"` // for manifest content type, empty until subtrie is evaluated
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ContentType string `json:"contentType"`
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Status int `json:"status"`
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subtrie *manifestTrie
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}
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func loadManifest(dpa *storage.DPA, hash storage.Key, quitC chan bool) (trie *manifestTrie, err error) { // non-recursive, subtrees are downloaded on-demand
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glog.V(logger.Detail).Infof("manifest lookup key: '%v'.", hash.Log())
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// retrieve manifest via DPA
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manifestReader := dpa.Retrieve(hash)
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return readManifest(manifestReader, hash, dpa, quitC)
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}
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func readManifest(manifestReader storage.LazySectionReader, hash storage.Key, dpa *storage.DPA, quitC chan bool) (trie *manifestTrie, err error) { // non-recursive, subtrees are downloaded on-demand
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// TODO check size for oversized manifests
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size, err := manifestReader.Size(quitC)
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if err != nil { // size == 0
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// can't determine size means we don't have the root chunk
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err = fmt.Errorf("Manifest not Found")
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return
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}
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manifestData := make([]byte, size)
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read, err := manifestReader.Read(manifestData)
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if int64(read) < size {
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glog.V(logger.Detail).Infof("Manifest %v not found.", hash.Log())
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if err == nil {
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err = fmt.Errorf("Manifest retrieval cut short: read %v, expect %v", read, size)
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}
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return
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}
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glog.V(logger.Detail).Infof("Manifest %v retrieved", hash.Log())
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man := manifestJSON{}
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err = json.Unmarshal(manifestData, &man)
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if err != nil {
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err = fmt.Errorf("Manifest %v is malformed: %v", hash.Log(), err)
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glog.V(logger.Detail).Infof("%v", err)
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return
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}
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glog.V(logger.Detail).Infof("Manifest %v has %d entries.", hash.Log(), len(man.Entries))
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trie = &manifestTrie{
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dpa: dpa,
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}
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for _, entry := range man.Entries {
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trie.addEntry(entry, quitC)
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}
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return
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}
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func (self *manifestTrie) addEntry(entry *manifestTrieEntry, quitC chan bool) {
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self.hash = nil // trie modified, hash needs to be re-calculated on demand
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if len(entry.Path) == 0 {
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self.entries[256] = entry
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return
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}
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b := byte(entry.Path[0])
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if (self.entries[b] == nil) || (self.entries[b].Path == entry.Path) {
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self.entries[b] = entry
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return
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}
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oldentry := self.entries[b]
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cpl := 0
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for (len(entry.Path) > cpl) && (len(oldentry.Path) > cpl) && (entry.Path[cpl] == oldentry.Path[cpl]) {
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cpl++
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}
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if (oldentry.ContentType == manifestType) && (cpl == len(oldentry.Path)) {
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if self.loadSubTrie(oldentry, quitC) != nil {
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return
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}
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entry.Path = entry.Path[cpl:]
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oldentry.subtrie.addEntry(entry, quitC)
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oldentry.Hash = ""
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return
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}
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commonPrefix := entry.Path[:cpl]
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subtrie := &manifestTrie{
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dpa: self.dpa,
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}
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entry.Path = entry.Path[cpl:]
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oldentry.Path = oldentry.Path[cpl:]
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subtrie.addEntry(entry, quitC)
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subtrie.addEntry(oldentry, quitC)
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self.entries[b] = &manifestTrieEntry{
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Path: commonPrefix,
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Hash: "",
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ContentType: manifestType,
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subtrie: subtrie,
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}
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}
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func (self *manifestTrie) getCountLast() (cnt int, entry *manifestTrieEntry) {
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for _, e := range self.entries {
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if e != nil {
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cnt++
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entry = e
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}
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}
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return
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}
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func (self *manifestTrie) deleteEntry(path string, quitC chan bool) {
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self.hash = nil // trie modified, hash needs to be re-calculated on demand
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if len(path) == 0 {
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self.entries[256] = nil
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return
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}
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b := byte(path[0])
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entry := self.entries[b]
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if entry == nil {
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return
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}
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if entry.Path == path {
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self.entries[b] = nil
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return
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}
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epl := len(entry.Path)
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if (entry.ContentType == manifestType) && (len(path) >= epl) && (path[:epl] == entry.Path) {
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if self.loadSubTrie(entry, quitC) != nil {
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return
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}
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entry.subtrie.deleteEntry(path[epl:], quitC)
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entry.Hash = ""
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// remove subtree if it has less than 2 elements
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cnt, lastentry := entry.subtrie.getCountLast()
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if cnt < 2 {
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if lastentry != nil {
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lastentry.Path = entry.Path + lastentry.Path
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}
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self.entries[b] = lastentry
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}
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}
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}
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func (self *manifestTrie) recalcAndStore() error {
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if self.hash != nil {
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return nil
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}
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var buffer bytes.Buffer
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buffer.WriteString(`{"entries":[`)
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list := &manifestJSON{}
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for _, entry := range self.entries {
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if entry != nil {
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if entry.Hash == "" { // TODO: paralellize
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err := entry.subtrie.recalcAndStore()
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if err != nil {
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return err
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}
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entry.Hash = entry.subtrie.hash.String()
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}
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list.Entries = append(list.Entries, entry)
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}
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}
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manifest, err := json.Marshal(list)
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if err != nil {
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return err
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}
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sr := bytes.NewReader(manifest)
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wg := &sync.WaitGroup{}
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key, err2 := self.dpa.Store(sr, int64(len(manifest)), wg, nil)
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wg.Wait()
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self.hash = key
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return err2
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}
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func (self *manifestTrie) loadSubTrie(entry *manifestTrieEntry, quitC chan bool) (err error) {
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if entry.subtrie == nil {
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hash := common.Hex2Bytes(entry.Hash)
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entry.subtrie, err = loadManifest(self.dpa, hash, quitC)
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entry.Hash = "" // might not match, should be recalculated
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}
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return
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}
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func (self *manifestTrie) listWithPrefixInt(prefix, rp string, quitC chan bool, cb func(entry *manifestTrieEntry, suffix string)) error {
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plen := len(prefix)
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var start, stop int
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if plen == 0 {
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start = 0
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stop = 256
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} else {
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start = int(prefix[0])
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stop = start
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}
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for i := start; i <= stop; i++ {
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select {
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case <-quitC:
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return fmt.Errorf("aborted")
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default:
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}
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entry := self.entries[i]
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if entry != nil {
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epl := len(entry.Path)
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if entry.ContentType == manifestType {
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l := plen
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if epl < l {
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l = epl
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}
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if prefix[:l] == entry.Path[:l] {
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err := self.loadSubTrie(entry, quitC)
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if err != nil {
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return err
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}
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err = entry.subtrie.listWithPrefixInt(prefix[l:], rp+entry.Path[l:], quitC, cb)
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if err != nil {
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return err
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}
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}
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} else {
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if (epl >= plen) && (prefix == entry.Path[:plen]) {
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cb(entry, rp+entry.Path[plen:])
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}
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}
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}
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}
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return nil
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}
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func (self *manifestTrie) listWithPrefix(prefix string, quitC chan bool, cb func(entry *manifestTrieEntry, suffix string)) (err error) {
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return self.listWithPrefixInt(prefix, "", quitC, cb)
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}
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func (self *manifestTrie) findPrefixOf(path string, quitC chan bool) (entry *manifestTrieEntry, pos int) {
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glog.V(logger.Detail).Infof("findPrefixOf(%s)", path)
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if len(path) == 0 {
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return self.entries[256], 0
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}
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b := byte(path[0])
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entry = self.entries[b]
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if entry == nil {
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return self.entries[256], 0
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}
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epl := len(entry.Path)
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glog.V(logger.Detail).Infof("path = %v entry.Path = %v epl = %v", path, entry.Path, epl)
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if (len(path) >= epl) && (path[:epl] == entry.Path) {
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glog.V(logger.Detail).Infof("entry.ContentType = %v", entry.ContentType)
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if entry.ContentType == manifestType {
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if self.loadSubTrie(entry, quitC) != nil {
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return nil, 0
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}
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entry, pos = entry.subtrie.findPrefixOf(path[epl:], quitC)
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if entry != nil {
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pos += epl
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}
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} else {
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pos = epl
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}
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} else {
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entry = nil
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}
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return
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}
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// file system manifest always contains regularized paths
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// no leading or trailing slashes, only single slashes inside
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func RegularSlashes(path string) (res string) {
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for i := 0; i < len(path); i++ {
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if (path[i] != '/') || ((i > 0) && (path[i-1] != '/')) {
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res = res + path[i:i+1]
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}
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}
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if (len(res) > 0) && (res[len(res)-1] == '/') {
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res = res[:len(res)-1]
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}
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return
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}
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func (self *manifestTrie) getEntry(spath string) (entry *manifestTrieEntry, fullpath string) {
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path := RegularSlashes(spath)
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var pos int
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quitC := make(chan bool)
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entry, pos = self.findPrefixOf(path, quitC)
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return entry, path[:pos]
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}
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