aboutsummaryrefslogtreecommitdiffstats
path: root/swarm/api/manifest.go
blob: 28597636eed67dd58cab043b8912a987c23daeb8 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
// 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"
    "encoding/json"
    "errors"
    "fmt"
    "io"
    "net/http"
    "strings"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/swarm/log"
    "github.com/ethereum/go-ethereum/swarm/storage"
)

const (
    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(toEncrypt bool) (storage.Address, error) {
    var manifest Manifest
    data, err := json.Marshal(&manifest)
    if err != nil {
        return nil, err
    }
    key, wait, err := a.Store(bytes.NewReader(data), int64(len(data)), toEncrypt)
    wait()
    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(resourceAddr string) (storage.Address, error) {
    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(bytes.NewReader(data), int64(len(data)), false)
    return key, err
}

// ManifestWriter is used to add and remove entries from an underlying manifest
type ManifestWriter struct {
    api   *API
    trie  *manifestTrie
    quitC chan bool
}

func (a *API) NewManifestWriter(addr storage.Address, quitC chan bool) (*ManifestWriter, error) {
    trie, err := loadManifest(a.fileStore, addr, quitC)
    if err != nil {
        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(data io.Reader, e *ManifestEntry) (storage.Address, error) {

    key, _, err := m.api.Store(data, e.Size, m.trie.encrypted)
    if err != nil {
        return nil, err
    }
    entry := newManifestTrieEntry(e, nil)
    entry.Hash = key.Hex()
    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
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 {
    api   *API
    trie  *manifestTrie
    quitC chan bool
}

func (a *API) NewManifestWalker(addr storage.Address, quitC chan bool) (*ManifestWalker, error) {
    trie, err := loadManifest(a.fileStore, addr, quitC)
    if err != nil {
        return nil, fmt.Errorf("error loading manifest %s: %s", addr, err)
    }
    return &ManifestWalker{a, trie, quitC}, nil
}

// ErrSkipManifest is used as a return value from WalkFn to indicate that the
// manifest should be skipped
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 {
            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 {
    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(fileStore *storage.FileStore, hash storage.Address, quitC chan bool) (trie *manifestTrie, err error) { // non-recursive, subtrees are downloaded on-demand
    log.Trace("manifest lookup", "key", hash)
    // retrieve manifest via FileStore
    manifestReader, isEncrypted := fileStore.Retrieve(hash)
    log.Trace("reader retrieved", "key", hash)
    return readManifest(manifestReader, hash, fileStore, isEncrypted, quitC)
}

func readManifest(manifestReader 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 := manifestReader.Size(quitC)
    if err != nil { // size == 0
        // can't determine size means we don't have the root chunk
        log.Trace("manifest not found", "key", hash)
        err = fmt.Errorf("Manifest not Found")
        return
    }
    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 := manifestReader.Read(manifestData)
    if int64(read) < size {
        log.Trace("manifest not found", "key", hash)
        if err == nil {
            err = fmt.Errorf("Manifest retrieval cut short: read %v, expect %v", read, size)
        }
        return
    }

    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)
        log.Trace("malformed manifest", "key", hash)
        return
    }

    log.Trace("manifest entries", "key", hash, "len", len(man.Entries))

    trie = &manifestTrie{
        fileStore: fileStore,
        encrypted: isEncrypted,
    }
    for _, entry := range man.Entries {
        trie.addEntry(entry, quitC)
    }
    return
}

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 {
        mt.entries[256] = entry
        return
    }

    b := entry.Path[0]
    oldentry := mt.entries[b]
    if (oldentry == nil) || (oldentry.Path == entry.Path && oldentry.ContentType != ManifestType) {
        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)) {
        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{
        fileStore: mt.fileStore,
        encrypted: mt.encrypted,
    }
    entry.Path = entry.Path[cpl:]
    oldentry.Path = oldentry.Path[cpl:]
    subtrie.addEntry(entry, quitC)
    subtrie.addEntry(oldentry, quitC)

    mt.entries[b] = newManifestTrieEntry(&ManifestEntry{
        Path:        commonPrefix,
        ContentType: ManifestType,
    }, subtrie)
}

func (mt *manifestTrie) getCountLast() (cnt int, entry *manifestTrieEntry) {
    for _, e := range mt.entries {
        if e != nil {
            cnt++
            entry = e
        }
    }
    return
}

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 {
        mt.entries[256] = nil
        return
    }

    b := path[0]
    entry := mt.entries[b]
    if entry == nil {
        return
    }
    if entry.Path == path {
        mt.entries[b] = nil
        return
    }

    epl := len(entry.Path)
    if (entry.ContentType == ManifestType) && (len(path) >= epl) && (path[:epl] == entry.Path) {
        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
            }
            mt.entries[b] = lastentry
        }
    }
}

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
                }
                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)
    key, wait, err2 := mt.fileStore.Store(sr, int64(len(manifest)), mt.encrypted)
    wait()
    mt.ref = key
    return err2
}

func (mt *manifestTrie) loadSubTrie(entry *manifestTrieEntry, quitC chan bool) (err error) {
    if entry.subtrie == nil {
        hash := common.Hex2Bytes(entry.Hash)
        entry.subtrie, err = loadManifest(mt.fileStore, hash, quitC)
        entry.Hash = "" // might not match, should be recalculated
    }
    return
}

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:
        }
        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] {
                    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
}

func (mt *manifestTrie) listWithPrefix(prefix string, quitC chan bool, cb func(entry *manifestTrieEntry, suffix string)) (err error) {
    return mt.listWithPrefixInt(prefix, "", quitC, cb)
}

func (mt *manifestTrie) findPrefixOf(path string, quitC chan bool) (entry *manifestTrieEntry, pos int) {
    log.Trace(fmt.Sprintf("findPrefixOf(%s)", path))

    if len(path) == 0 {
        return mt.entries[256], 0
    }

    //see if first char is in manifest entries
    b := path[0]
    entry = mt.entries[b]
    if entry == nil {
        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 {
                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)) {
            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
        }
    }
    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
}

func (mt *manifestTrie) getEntry(spath string) (entry *manifestTrieEntry, fullpath string) {
    path := RegularSlashes(spath)
    var pos int
    quitC := make(chan bool)
    entry, pos = mt.findPrefixOf(path, quitC)
    return entry, path[:pos]
}