plugeth/swarm/api/manifest.go

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// Copyright 2016 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 api
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"strings"
"time"
"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/swarm/log"
"github.com/ethereum/go-ethereum/swarm/storage"
)
const (
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ManifestType = "application/bzz-manifest+json"
ResourceContentType = "application/bzz-resource"
manifestSizeLimit = 5 * 1024 * 1024
)
// Manifest represents a swarm manifest
type Manifest struct {
Entries []ManifestEntry `json:"entries,omitempty"`
}
// ManifestEntry represents an entry in a swarm manifest
type ManifestEntry struct {
Hash string `json:"hash,omitempty"`
Path string `json:"path,omitempty"`
ContentType string `json:"contentType,omitempty"`
Mode int64 `json:"mode,omitempty"`
Size int64 `json:"size,omitempty"`
ModTime time.Time `json:"mod_time,omitempty"`
Status int `json:"status,omitempty"`
}
// ManifestList represents the result of listing files in a manifest
type ManifestList struct {
CommonPrefixes []string `json:"common_prefixes,omitempty"`
Entries []*ManifestEntry `json:"entries,omitempty"`
}
// NewManifest creates and stores a new, empty manifest
func (a *API) NewManifest(ctx context.Context, toEncrypt bool) (storage.Address, error) {
var manifest Manifest
data, err := json.Marshal(&manifest)
if err != nil {
return nil, err
}
key, wait, err := a.Store(ctx, bytes.NewReader(data), int64(len(data)), toEncrypt)
wait(ctx)
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return key, err
}
// Manifest hack for supporting Mutable Resource Updates from the bzz: scheme
// see swarm/api/api.go:API.Get() for more information
func (a *API) NewResourceManifest(ctx context.Context, resourceAddr string) (storage.Address, error) {
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var manifest Manifest
entry := ManifestEntry{
Hash: resourceAddr,
ContentType: ResourceContentType,
}
manifest.Entries = append(manifest.Entries, entry)
data, err := json.Marshal(&manifest)
if err != nil {
return nil, err
}
key, _, err := a.Store(ctx, bytes.NewReader(data), int64(len(data)), false)
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return key, err
}
// ManifestWriter is used to add and remove entries from an underlying manifest
type ManifestWriter struct {
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api *API
trie *manifestTrie
quitC chan bool
}
func (a *API) NewManifestWriter(ctx context.Context, addr storage.Address, quitC chan bool) (*ManifestWriter, error) {
trie, err := loadManifest(ctx, a.fileStore, addr, quitC)
if err != nil {
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return nil, fmt.Errorf("error loading manifest %s: %s", addr, err)
}
return &ManifestWriter{a, trie, quitC}, nil
}
// AddEntry stores the given data and adds the resulting key to the manifest
func (m *ManifestWriter) AddEntry(ctx context.Context, data io.Reader, e *ManifestEntry) (key storage.Address, err error) {
entry := newManifestTrieEntry(e, nil)
if data != nil {
key, _, err = m.api.Store(ctx, data, e.Size, m.trie.encrypted)
if err != nil {
return nil, err
}
entry.Hash = key.Hex()
}
if entry.Hash == "" {
return key, errors.New("missing entry hash")
}
m.trie.addEntry(entry, m.quitC)
return key, nil
}
// RemoveEntry removes the given path from the manifest
func (m *ManifestWriter) RemoveEntry(path string) error {
m.trie.deleteEntry(path, m.quitC)
return nil
}
// Store stores the manifest, returning the resulting storage key
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func (m *ManifestWriter) Store() (storage.Address, error) {
return m.trie.ref, m.trie.recalcAndStore()
}
// ManifestWalker is used to recursively walk the entries in the manifest and
// all of its submanifests
type ManifestWalker struct {
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api *API
trie *manifestTrie
quitC chan bool
}
func (a *API) NewManifestWalker(ctx context.Context, addr storage.Address, quitC chan bool) (*ManifestWalker, error) {
trie, err := loadManifest(ctx, a.fileStore, addr, quitC)
if err != nil {
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return nil, fmt.Errorf("error loading manifest %s: %s", addr, err)
}
return &ManifestWalker{a, trie, quitC}, nil
}
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// ErrSkipManifest is used as a return value from WalkFn to indicate that the
// manifest should be skipped
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var ErrSkipManifest = errors.New("skip this manifest")
// WalkFn is the type of function called for each entry visited by a recursive
// manifest walk
type WalkFn func(entry *ManifestEntry) error
// Walk recursively walks the manifest calling walkFn for each entry in the
// manifest, including submanifests
func (m *ManifestWalker) Walk(walkFn WalkFn) error {
return m.walk(m.trie, "", walkFn)
}
func (m *ManifestWalker) walk(trie *manifestTrie, prefix string, walkFn WalkFn) error {
for _, entry := range &trie.entries {
if entry == nil {
continue
}
entry.Path = prefix + entry.Path
err := walkFn(&entry.ManifestEntry)
if err != nil {
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if entry.ContentType == ManifestType && err == ErrSkipManifest {
continue
}
return err
}
if entry.ContentType != ManifestType {
continue
}
if err := trie.loadSubTrie(entry, nil); err != nil {
return err
}
if err := m.walk(entry.subtrie, entry.Path, walkFn); err != nil {
return err
}
}
return nil
}
type manifestTrie struct {
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fileStore *storage.FileStore
entries [257]*manifestTrieEntry // indexed by first character of basePath, entries[256] is the empty basePath entry
ref storage.Address // if ref != nil, it is stored
encrypted bool
}
func newManifestTrieEntry(entry *ManifestEntry, subtrie *manifestTrie) *manifestTrieEntry {
return &manifestTrieEntry{
ManifestEntry: *entry,
subtrie: subtrie,
}
}
type manifestTrieEntry struct {
ManifestEntry
subtrie *manifestTrie
}
func loadManifest(ctx context.Context, fileStore *storage.FileStore, hash storage.Address, quitC chan bool) (trie *manifestTrie, err error) { // non-recursive, subtrees are downloaded on-demand
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log.Trace("manifest lookup", "key", hash)
// retrieve manifest via FileStore
manifestReader, isEncrypted := fileStore.Retrieve(ctx, hash)
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log.Trace("reader retrieved", "key", hash)
return readManifest(manifestReader, hash, fileStore, isEncrypted, quitC)
}
func readManifest(mr storage.LazySectionReader, hash storage.Address, fileStore *storage.FileStore, isEncrypted bool, quitC chan bool) (trie *manifestTrie, err error) { // non-recursive, subtrees are downloaded on-demand
// TODO check size for oversized manifests
size, err := mr.Size(mr.Context(), quitC)
if err != nil { // size == 0
// can't determine size means we don't have the root chunk
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log.Trace("manifest not found", "key", hash)
err = fmt.Errorf("Manifest not Found")
return
}
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if size > manifestSizeLimit {
log.Warn("manifest exceeds size limit", "key", hash, "size", size, "limit", manifestSizeLimit)
err = fmt.Errorf("Manifest size of %v bytes exceeds the %v byte limit", size, manifestSizeLimit)
return
}
manifestData := make([]byte, size)
read, err := mr.Read(manifestData)
if int64(read) < size {
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log.Trace("manifest not found", "key", hash)
if err == nil {
err = fmt.Errorf("Manifest retrieval cut short: read %v, expect %v", read, size)
}
return
}
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log.Debug("manifest retrieved", "key", hash)
var man struct {
Entries []*manifestTrieEntry `json:"entries"`
}
err = json.Unmarshal(manifestData, &man)
if err != nil {
err = fmt.Errorf("Manifest %v is malformed: %v", hash.Log(), err)
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log.Trace("malformed manifest", "key", hash)
return
}
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log.Trace("manifest entries", "key", hash, "len", len(man.Entries))
trie = &manifestTrie{
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fileStore: fileStore,
encrypted: isEncrypted,
}
for _, entry := range man.Entries {
trie.addEntry(entry, quitC)
}
return
}
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func (mt *manifestTrie) addEntry(entry *manifestTrieEntry, quitC chan bool) {
mt.ref = nil // trie modified, hash needs to be re-calculated on demand
if len(entry.Path) == 0 {
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mt.entries[256] = entry
return
}
b := entry.Path[0]
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oldentry := mt.entries[b]
if (oldentry == nil) || (oldentry.Path == entry.Path && oldentry.ContentType != ManifestType) {
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mt.entries[b] = entry
return
}
cpl := 0
for (len(entry.Path) > cpl) && (len(oldentry.Path) > cpl) && (entry.Path[cpl] == oldentry.Path[cpl]) {
cpl++
}
if (oldentry.ContentType == ManifestType) && (cpl == len(oldentry.Path)) {
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if mt.loadSubTrie(oldentry, quitC) != nil {
return
}
entry.Path = entry.Path[cpl:]
oldentry.subtrie.addEntry(entry, quitC)
oldentry.Hash = ""
return
}
commonPrefix := entry.Path[:cpl]
subtrie := &manifestTrie{
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fileStore: mt.fileStore,
encrypted: mt.encrypted,
}
entry.Path = entry.Path[cpl:]
oldentry.Path = oldentry.Path[cpl:]
subtrie.addEntry(entry, quitC)
subtrie.addEntry(oldentry, quitC)
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mt.entries[b] = newManifestTrieEntry(&ManifestEntry{
Path: commonPrefix,
ContentType: ManifestType,
}, subtrie)
}
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func (mt *manifestTrie) getCountLast() (cnt int, entry *manifestTrieEntry) {
for _, e := range &mt.entries {
if e != nil {
cnt++
entry = e
}
}
return
}
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func (mt *manifestTrie) deleteEntry(path string, quitC chan bool) {
mt.ref = nil // trie modified, hash needs to be re-calculated on demand
if len(path) == 0 {
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mt.entries[256] = nil
return
}
b := path[0]
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entry := mt.entries[b]
if entry == nil {
return
}
if entry.Path == path {
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mt.entries[b] = nil
return
}
epl := len(entry.Path)
if (entry.ContentType == ManifestType) && (len(path) >= epl) && (path[:epl] == entry.Path) {
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if mt.loadSubTrie(entry, quitC) != nil {
return
}
entry.subtrie.deleteEntry(path[epl:], quitC)
entry.Hash = ""
// remove subtree if it has less than 2 elements
cnt, lastentry := entry.subtrie.getCountLast()
if cnt < 2 {
if lastentry != nil {
lastentry.Path = entry.Path + lastentry.Path
}
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mt.entries[b] = lastentry
}
}
}
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func (mt *manifestTrie) recalcAndStore() error {
if mt.ref != nil {
return nil
}
var buffer bytes.Buffer
buffer.WriteString(`{"entries":[`)
list := &Manifest{}
for _, entry := range &mt.entries {
if entry != nil {
if entry.Hash == "" { // TODO: paralellize
err := entry.subtrie.recalcAndStore()
if err != nil {
return err
}
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entry.Hash = entry.subtrie.ref.Hex()
}
list.Entries = append(list.Entries, entry.ManifestEntry)
}
}
manifest, err := json.Marshal(list)
if err != nil {
return err
}
sr := bytes.NewReader(manifest)
ctx := context.TODO()
key, wait, err2 := mt.fileStore.Store(ctx, sr, int64(len(manifest)), mt.encrypted)
if err2 != nil {
return err2
}
err2 = wait(ctx)
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mt.ref = key
return err2
}
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func (mt *manifestTrie) loadSubTrie(entry *manifestTrieEntry, quitC chan bool) (err error) {
if entry.subtrie == nil {
hash := common.Hex2Bytes(entry.Hash)
entry.subtrie, err = loadManifest(context.TODO(), mt.fileStore, hash, quitC)
entry.Hash = "" // might not match, should be recalculated
}
return
}
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func (mt *manifestTrie) listWithPrefixInt(prefix, rp string, quitC chan bool, cb func(entry *manifestTrieEntry, suffix string)) error {
plen := len(prefix)
var start, stop int
if plen == 0 {
start = 0
stop = 256
} else {
start = int(prefix[0])
stop = start
}
for i := start; i <= stop; i++ {
select {
case <-quitC:
return fmt.Errorf("aborted")
default:
}
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entry := mt.entries[i]
if entry != nil {
epl := len(entry.Path)
if entry.ContentType == ManifestType {
l := plen
if epl < l {
l = epl
}
if prefix[:l] == entry.Path[:l] {
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err := mt.loadSubTrie(entry, quitC)
if err != nil {
return err
}
err = entry.subtrie.listWithPrefixInt(prefix[l:], rp+entry.Path[l:], quitC, cb)
if err != nil {
return err
}
}
} else {
if (epl >= plen) && (prefix == entry.Path[:plen]) {
cb(entry, rp+entry.Path[plen:])
}
}
}
}
return nil
}
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func (mt *manifestTrie) listWithPrefix(prefix string, quitC chan bool, cb func(entry *manifestTrieEntry, suffix string)) (err error) {
return mt.listWithPrefixInt(prefix, "", quitC, cb)
}
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func (mt *manifestTrie) findPrefixOf(path string, quitC chan bool) (entry *manifestTrieEntry, pos int) {
log.Trace(fmt.Sprintf("findPrefixOf(%s)", path))
if len(path) == 0 {
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return mt.entries[256], 0
}
//see if first char is in manifest entries
b := path[0]
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entry = mt.entries[b]
if entry == nil {
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return mt.entries[256], 0
}
epl := len(entry.Path)
log.Trace(fmt.Sprintf("path = %v entry.Path = %v epl = %v", path, entry.Path, epl))
if len(path) <= epl {
if entry.Path[:len(path)] == path {
if entry.ContentType == ManifestType {
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err := mt.loadSubTrie(entry, quitC)
if err == nil && entry.subtrie != nil {
subentries := entry.subtrie.entries
for i := 0; i < len(subentries); i++ {
sub := subentries[i]
if sub != nil && sub.Path == "" {
return sub, len(path)
}
}
}
entry.Status = http.StatusMultipleChoices
}
pos = len(path)
return
}
return nil, 0
}
if path[:epl] == entry.Path {
log.Trace(fmt.Sprintf("entry.ContentType = %v", entry.ContentType))
//the subentry is a manifest, load subtrie
if entry.ContentType == ManifestType && (strings.Contains(entry.Path, path) || strings.Contains(path, entry.Path)) {
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err := mt.loadSubTrie(entry, quitC)
if err != nil {
return nil, 0
}
sub, pos := entry.subtrie.findPrefixOf(path[epl:], quitC)
if sub != nil {
entry = sub
pos += epl
return sub, pos
} else if path == entry.Path {
entry.Status = http.StatusMultipleChoices
}
} else {
//entry is not a manifest, return it
if path != entry.Path {
return nil, 0
}
pos = epl
}
}
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return nil, 0
}
// file system manifest always contains regularized paths
// no leading or trailing slashes, only single slashes inside
func RegularSlashes(path string) (res string) {
for i := 0; i < len(path); i++ {
if (path[i] != '/') || ((i > 0) && (path[i-1] != '/')) {
res = res + path[i:i+1]
}
}
if (len(res) > 0) && (res[len(res)-1] == '/') {
res = res[:len(res)-1]
}
return
}
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func (mt *manifestTrie) getEntry(spath string) (entry *manifestTrieEntry, fullpath string) {
path := RegularSlashes(spath)
var pos int
quitC := make(chan bool)
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entry, pos = mt.findPrefixOf(path, quitC)
return entry, path[:pos]
}