forked from cerc-io/plugeth
60c858a529
Previously, NewManifest was asynchronous so subsequent code which tried to use the returned manifest could error as the manifest was not yet persisted.
471 lines
12 KiB
Go
471 lines
12 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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"errors"
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"fmt"
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"io"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/log"
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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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// Manifest represents a swarm manifest
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type Manifest struct {
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Entries []ManifestEntry `json:"entries,omitempty"`
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}
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// ManifestEntry represents an entry in a swarm manifest
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type ManifestEntry struct {
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Hash string `json:"hash,omitempty"`
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Path string `json:"path,omitempty"`
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ContentType string `json:"contentType,omitempty"`
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Mode int64 `json:"mode,omitempty"`
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Size int64 `json:"size,omitempty"`
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ModTime time.Time `json:"mod_time,omitempty"`
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Status int `json:"status,omitempty"`
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}
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// ManifestList represents the result of listing files in a manifest
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type ManifestList struct {
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CommonPrefixes []string `json:"common_prefixes,omitempty"`
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Entries []*ManifestEntry `json:"entries,omitempty"`
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}
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// NewManifest creates and stores a new, empty manifest
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func (a *Api) NewManifest() (storage.Key, error) {
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var manifest Manifest
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data, err := json.Marshal(&manifest)
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if err != nil {
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return nil, err
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}
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return a.Store(bytes.NewReader(data), int64(len(data)), &sync.WaitGroup{})
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}
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// ManifestWriter is used to add and remove entries from an underlying manifest
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type ManifestWriter struct {
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api *Api
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trie *manifestTrie
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quitC chan bool
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}
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func (a *Api) NewManifestWriter(key storage.Key, quitC chan bool) (*ManifestWriter, error) {
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trie, err := loadManifest(a.dpa, key, quitC)
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if err != nil {
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return nil, fmt.Errorf("error loading manifest %s: %s", key, err)
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}
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return &ManifestWriter{a, trie, quitC}, nil
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}
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// AddEntry stores the given data and adds the resulting key to the manifest
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func (m *ManifestWriter) AddEntry(data io.Reader, e *ManifestEntry) (storage.Key, error) {
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key, err := m.api.Store(data, e.Size, nil)
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if err != nil {
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return nil, err
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}
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entry := newManifestTrieEntry(e, nil)
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entry.Hash = key.String()
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m.trie.addEntry(entry, m.quitC)
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return key, nil
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}
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// RemoveEntry removes the given path from the manifest
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func (m *ManifestWriter) RemoveEntry(path string) error {
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m.trie.deleteEntry(path, m.quitC)
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return nil
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}
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// Store stores the manifest, returning the resulting storage key
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func (m *ManifestWriter) Store() (storage.Key, error) {
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return m.trie.hash, m.trie.recalcAndStore()
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}
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// ManifestWalker is used to recursively walk the entries in the manifest and
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// all of its submanifests
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type ManifestWalker struct {
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api *Api
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trie *manifestTrie
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quitC chan bool
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}
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func (a *Api) NewManifestWalker(key storage.Key, quitC chan bool) (*ManifestWalker, error) {
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trie, err := loadManifest(a.dpa, key, quitC)
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if err != nil {
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return nil, fmt.Errorf("error loading manifest %s: %s", key, err)
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}
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return &ManifestWalker{a, trie, quitC}, nil
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}
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// SkipManifest is used as a return value from WalkFn to indicate that the
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// manifest should be skipped
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var SkipManifest = errors.New("skip this manifest")
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// WalkFn is the type of function called for each entry visited by a recursive
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// manifest walk
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type WalkFn func(entry *ManifestEntry) error
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// Walk recursively walks the manifest calling walkFn for each entry in the
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// manifest, including submanifests
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func (m *ManifestWalker) Walk(walkFn WalkFn) error {
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return m.walk(m.trie, "", walkFn)
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}
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func (m *ManifestWalker) walk(trie *manifestTrie, prefix string, walkFn WalkFn) error {
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for _, entry := range trie.entries {
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if entry == nil {
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continue
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}
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entry.Path = prefix + entry.Path
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err := walkFn(&entry.ManifestEntry)
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if err != nil {
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if entry.ContentType == ManifestType && err == SkipManifest {
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continue
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}
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return err
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}
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if entry.ContentType != ManifestType {
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continue
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}
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if err := trie.loadSubTrie(entry, nil); err != nil {
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return err
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}
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if err := m.walk(entry.subtrie, entry.Path, walkFn); err != nil {
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return err
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}
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}
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return nil
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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 basePath, entries[256] is the empty basePath entry
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hash storage.Key // if hash != nil, it is stored
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}
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func newManifestTrieEntry(entry *ManifestEntry, subtrie *manifestTrie) *manifestTrieEntry {
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return &manifestTrieEntry{
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ManifestEntry: *entry,
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subtrie: subtrie,
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}
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}
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type manifestTrieEntry struct {
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ManifestEntry
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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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log.Trace(fmt.Sprintf("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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log.Trace(fmt.Sprintf("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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log.Trace(fmt.Sprintf("Manifest %v retrieved", hash.Log()))
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var man struct {
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Entries []*manifestTrieEntry `json:"entries"`
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}
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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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log.Trace(fmt.Sprintf("%v", err))
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return
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}
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log.Trace(fmt.Sprintf("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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oldentry := self.entries[b]
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if (oldentry == nil) || (oldentry.Path == entry.Path && oldentry.ContentType != ManifestType) {
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self.entries[b] = entry
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return
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}
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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] = newManifestTrieEntry(&ManifestEntry{
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Path: commonPrefix,
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ContentType: ManifestType,
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}, subtrie)
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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 := &Manifest{}
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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.ManifestEntry)
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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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log.Trace(fmt.Sprintf("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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log.Trace(fmt.Sprintf("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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log.Trace(fmt.Sprintf("entry.ContentType = %v", entry.ContentType))
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if entry.ContentType == ManifestType {
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err := self.loadSubTrie(entry, quitC)
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if err != 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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}
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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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