aboutsummaryrefslogtreecommitdiff
path: root/eth/filters/api.go
blob: 9ee96af35794cb22ed242505e70a57e8ef32c1c5 (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
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package filters

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"math/big"
	"sync"
	"time"

	"github.com/ava-labs/coreth/core/types"
	"github.com/ava-labs/coreth/rpc"
	ethereum "github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/event"
)

var (
	deadline = 5 * time.Minute // consider a filter inactive if it has not been polled for within deadline
)

// filter is a helper struct that holds meta information over the filter type
// and associated subscription in the event system.
type filter struct {
	typ      Type
	deadline *time.Timer // filter is inactiv when deadline triggers
	hashes   []common.Hash
	crit     FilterCriteria
	logs     []*types.Log
	s        *Subscription // associated subscription in event system
}

// PublicFilterAPI offers support to create and manage filters. This will allow external clients to retrieve various
// information related to the Ethereum protocol such als blocks, transactions and logs.
type PublicFilterAPI struct {
	backend   Backend
	mux       *event.TypeMux
	quit      chan struct{}
	chainDb   ethdb.Database
	events    *EventSystem
	filtersMu sync.Mutex
	filters   map[rpc.ID]*filter
}

// NewPublicFilterAPI returns a new PublicFilterAPI instance.
func NewPublicFilterAPI(backend Backend, lightMode bool) *PublicFilterAPI {
	api := &PublicFilterAPI{
		backend: backend,
		chainDb: backend.ChainDb(),
		events:  NewEventSystem(backend, lightMode),
		filters: make(map[rpc.ID]*filter),
	}
	go api.timeoutLoop()

	return api
}

// timeoutLoop runs every 5 minutes and deletes filters that have not been recently used.
// Tt is started when the api is created.
func (api *PublicFilterAPI) timeoutLoop() {
	ticker := time.NewTicker(5 * time.Minute)
	defer ticker.Stop()
	for {
		<-ticker.C
		api.filtersMu.Lock()
		for id, f := range api.filters {
			select {
			case <-f.deadline.C:
				f.s.Unsubscribe()
				delete(api.filters, id)
			default:
				continue
			}
		}
		api.filtersMu.Unlock()
	}
}

// NewPendingTransactionFilter creates a filter that fetches pending transaction hashes
// as transactions enter the pending state.
//
// It is part of the filter package because this filter can be used through the
// `eth_getFilterChanges` polling method that is also used for log filters.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newpendingtransactionfilter
func (api *PublicFilterAPI) NewPendingTransactionFilter() rpc.ID {
	var (
		pendingTxs   = make(chan []common.Hash)
		pendingTxSub = api.events.SubscribePendingTxs(pendingTxs)
	)

	api.filtersMu.Lock()
	api.filters[pendingTxSub.ID] = &filter{typ: PendingTransactionsSubscription, deadline: time.NewTimer(deadline), hashes: make([]common.Hash, 0), s: pendingTxSub}
	api.filtersMu.Unlock()

	go func() {
		for {
			select {
			case ph := <-pendingTxs:
				api.filtersMu.Lock()
				if f, found := api.filters[pendingTxSub.ID]; found {
					f.hashes = append(f.hashes, ph...)
				}
				api.filtersMu.Unlock()
			case <-pendingTxSub.Err():
				api.filtersMu.Lock()
				delete(api.filters, pendingTxSub.ID)
				api.filtersMu.Unlock()
				return
			}
		}
	}()

	return pendingTxSub.ID
}

// NewPendingTransactions creates a subscription that is triggered each time a transaction
// enters the transaction pool and was signed from one of the transactions this nodes manages.
func (api *PublicFilterAPI) NewPendingTransactions(ctx context.Context) (*rpc.Subscription, error) {
	notifier, supported := rpc.NotifierFromContext(ctx)
	if !supported {
		return &rpc.Subscription{}, rpc.ErrNotificationsUnsupported
	}

	rpcSub := notifier.CreateSubscription()

	go func() {
		txHashes := make(chan []common.Hash, 128)
		pendingTxSub := api.events.SubscribePendingTxs(txHashes)

		for {
			select {
			case hashes := <-txHashes:
				// To keep the original behaviour, send a single tx hash in one notification.
				// TODO(rjl493456442) Send a batch of tx hashes in one notification
				for _, h := range hashes {
					notifier.Notify(rpcSub.ID, h)
				}
			case <-rpcSub.Err():
				pendingTxSub.Unsubscribe()
				return
			case <-notifier.Closed():
				pendingTxSub.Unsubscribe()
				return
			}
		}
	}()

	return rpcSub, nil
}

// NewBlockFilter creates a filter that fetches blocks that are imported into the chain.
// It is part of the filter package since polling goes with eth_getFilterChanges.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newblockfilter
func (api *PublicFilterAPI) NewBlockFilter() rpc.ID {
	var (
		headers   = make(chan *types.Header)
		headerSub = api.events.SubscribeNewHeads(headers)
	)

	api.filtersMu.Lock()
	api.filters[headerSub.ID] = &filter{typ: BlocksSubscription, deadline: time.NewTimer(deadline), hashes: make([]common.Hash, 0), s: headerSub}
	api.filtersMu.Unlock()

	go func() {
		for {
			select {
			case h := <-headers:
				api.filtersMu.Lock()
				if f, found := api.filters[headerSub.ID]; found {
					f.hashes = append(f.hashes, h.Hash())
				}
				api.filtersMu.Unlock()
			case <-headerSub.Err():
				api.filtersMu.Lock()
				delete(api.filters, headerSub.ID)
				api.filtersMu.Unlock()
				return
			}
		}
	}()

	return headerSub.ID
}

// NewHeads send a notification each time a new (header) block is appended to the chain.
func (api *PublicFilterAPI) NewHeads(ctx context.Context) (*rpc.Subscription, error) {
	notifier, supported := rpc.NotifierFromContext(ctx)
	if !supported {
		return &rpc.Subscription{}, rpc.ErrNotificationsUnsupported
	}

	rpcSub := notifier.CreateSubscription()

	go func() {
		headers := make(chan *types.Header)
		headersSub := api.events.SubscribeNewHeads(headers)

		for {
			select {
			case h := <-headers:
				notifier.Notify(rpcSub.ID, h)
			case <-rpcSub.Err():
				headersSub.Unsubscribe()
				return
			case <-notifier.Closed():
				headersSub.Unsubscribe()
				return
			}
		}
	}()

	return rpcSub, nil
}

// Logs creates a subscription that fires for all new log that match the given filter criteria.
func (api *PublicFilterAPI) Logs(ctx context.Context, crit FilterCriteria) (*rpc.Subscription, error) {
	notifier, supported := rpc.NotifierFromContext(ctx)
	if !supported {
		return &rpc.Subscription{}, rpc.ErrNotificationsUnsupported
	}

	var (
		rpcSub      = notifier.CreateSubscription()
		matchedLogs = make(chan []*types.Log)
	)

	logsSub, err := api.events.SubscribeLogs(ethereum.FilterQuery(crit), matchedLogs)
	if err != nil {
		return nil, err
	}

	go func() {

		for {
			select {
			case logs := <-matchedLogs:
				for _, log := range logs {
					notifier.Notify(rpcSub.ID, &log)
				}
			case <-rpcSub.Err(): // client send an unsubscribe request
				logsSub.Unsubscribe()
				return
			case <-notifier.Closed(): // connection dropped
				logsSub.Unsubscribe()
				return
			}
		}
	}()

	return rpcSub, nil
}

// FilterCriteria represents a request to create a new filter.
// Same as ethereum.FilterQuery but with UnmarshalJSON() method.
type FilterCriteria ethereum.FilterQuery

// NewFilter creates a new filter and returns the filter id. It can be
// used to retrieve logs when the state changes. This method cannot be
// used to fetch logs that are already stored in the state.
//
// Default criteria for the from and to block are "latest".
// Using "latest" as block number will return logs for mined blocks.
// Using "pending" as block number returns logs for not yet mined (pending) blocks.
// In case logs are removed (chain reorg) previously returned logs are returned
// again but with the removed property set to true.
//
// In case "fromBlock" > "toBlock" an error is returned.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newfilter
func (api *PublicFilterAPI) NewFilter(crit FilterCriteria) (rpc.ID, error) {
	logs := make(chan []*types.Log)
	logsSub, err := api.events.SubscribeLogs(ethereum.FilterQuery(crit), logs)
	if err != nil {
		return rpc.ID(""), err
	}

	api.filtersMu.Lock()
	api.filters[logsSub.ID] = &filter{typ: LogsSubscription, crit: crit, deadline: time.NewTimer(deadline), logs: make([]*types.Log, 0), s: logsSub}
	api.filtersMu.Unlock()

	go func() {
		for {
			select {
			case l := <-logs:
				api.filtersMu.Lock()
				if f, found := api.filters[logsSub.ID]; found {
					f.logs = append(f.logs, l...)
				}
				api.filtersMu.Unlock()
			case <-logsSub.Err():
				api.filtersMu.Lock()
				delete(api.filters, logsSub.ID)
				api.filtersMu.Unlock()
				return
			}
		}
	}()

	return logsSub.ID, nil
}

// GetLogs returns logs matching the given argument that are stored within the state.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getlogs
func (api *PublicFilterAPI) GetLogs(ctx context.Context, crit FilterCriteria) ([]*types.Log, error) {
	var filter *Filter
	if crit.BlockHash != nil {
		// Block filter requested, construct a single-shot filter
		filter = NewBlockFilter(api.backend, *crit.BlockHash, crit.Addresses, crit.Topics)
	} else {
		// Convert the RPC block numbers into internal representations
		// LatestBlockNumber is left in place here to be handled
		// correctly within NewRangeFilter
		begin := rpc.LatestBlockNumber.Int64()
		if crit.FromBlock != nil {
			begin = crit.FromBlock.Int64()
		}
		end := rpc.LatestBlockNumber.Int64()
		if crit.ToBlock != nil {
			end = crit.ToBlock.Int64()
		}
		// Construct the range filter
		filter = NewRangeFilter(api.backend, begin, end, crit.Addresses, crit.Topics)
	}
	// Run the filter and return all the logs
	logs, err := filter.Logs(ctx)
	if err != nil {
		return nil, err
	}
	return returnLogs(logs), err
}

// UninstallFilter removes the filter with the given filter id.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_uninstallfilter
func (api *PublicFilterAPI) UninstallFilter(id rpc.ID) bool {
	api.filtersMu.Lock()
	f, found := api.filters[id]
	if found {
		delete(api.filters, id)
	}
	api.filtersMu.Unlock()
	if found {
		f.s.Unsubscribe()
	}

	return found
}

// GetFilterLogs returns the logs for the filter with the given id.
// If the filter could not be found an empty array of logs is returned.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getfilterlogs
func (api *PublicFilterAPI) GetFilterLogs(ctx context.Context, id rpc.ID) ([]*types.Log, error) {
	api.filtersMu.Lock()
	f, found := api.filters[id]
	api.filtersMu.Unlock()

	if !found || f.typ != LogsSubscription {
		return nil, fmt.Errorf("filter not found")
	}

	var filter *Filter
	if f.crit.BlockHash != nil {
		// Block filter requested, construct a single-shot filter
		filter = NewBlockFilter(api.backend, *f.crit.BlockHash, f.crit.Addresses, f.crit.Topics)
	} else {
		// Convert the RPC block numbers into internal representations
		// Leave LatestBlockNumber in place here as the defaults
		// Should be handled correctly as request for the last
		// accepted block instead throughout all APIs.
		begin := rpc.LatestBlockNumber.Int64()
		if f.crit.FromBlock != nil {
			begin = f.crit.FromBlock.Int64()
		}
		end := rpc.LatestBlockNumber.Int64()
		if f.crit.ToBlock != nil {
			end = f.crit.ToBlock.Int64()
		}
		// Construct the range filter
		filter = NewRangeFilter(api.backend, begin, end, f.crit.Addresses, f.crit.Topics)
	}
	// Run the filter and return all the logs
	logs, err := filter.Logs(ctx)
	if err != nil {
		return nil, err
	}
	return returnLogs(logs), nil
}

// GetFilterChanges returns the logs for the filter with the given id since
// last time it was called. This can be used for polling.
//
// For pending transaction and block filters the result is []common.Hash.
// (pending)Log filters return []Log.
//
// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getfilterchanges
func (api *PublicFilterAPI) GetFilterChanges(id rpc.ID) (interface{}, error) {
	api.filtersMu.Lock()
	defer api.filtersMu.Unlock()

	if f, found := api.filters[id]; found {
		if !f.deadline.Stop() {
			// timer expired but filter is not yet removed in timeout loop
			// receive timer value and reset timer
			<-f.deadline.C
		}
		f.deadline.Reset(deadline)

		switch f.typ {
		case PendingTransactionsSubscription, BlocksSubscription:
			hashes := f.hashes
			f.hashes = nil
			return returnHashes(hashes), nil
		case LogsSubscription, MinedAndPendingLogsSubscription:
			logs := f.logs
			f.logs = nil
			return returnLogs(logs), nil
		}
	}

	return []interface{}{}, fmt.Errorf("filter not found")
}

// returnHashes is a helper that will return an empty hash array case the given hash array is nil,
// otherwise the given hashes array is returned.
func returnHashes(hashes []common.Hash) []common.Hash {
	if hashes == nil {
		return []common.Hash{}
	}
	return hashes
}

// returnLogs is a helper that will return an empty log array in case the given logs array is nil,
// otherwise the given logs array is returned.
func returnLogs(logs []*types.Log) []*types.Log {
	if logs == nil {
		return []*types.Log{}
	}
	return logs
}

// UnmarshalJSON sets *args fields with given data.
func (args *FilterCriteria) UnmarshalJSON(data []byte) error {
	type input struct {
		BlockHash *common.Hash     `json:"blockHash"`
		FromBlock *rpc.BlockNumber `json:"fromBlock"`
		ToBlock   *rpc.BlockNumber `json:"toBlock"`
		Addresses interface{}      `json:"address"`
		Topics    []interface{}    `json:"topics"`
	}

	var raw input
	if err := json.Unmarshal(data, &raw); err != nil {
		return err
	}

	if raw.BlockHash != nil {
		if raw.FromBlock != nil || raw.ToBlock != nil {
			// BlockHash is mutually exclusive with FromBlock/ToBlock criteria
			return fmt.Errorf("cannot specify both BlockHash and FromBlock/ToBlock, choose one or the other")
		}
		args.BlockHash = raw.BlockHash
	} else {
		if raw.FromBlock != nil {
			args.FromBlock = big.NewInt(raw.FromBlock.Int64())
		}

		if raw.ToBlock != nil {
			args.ToBlock = big.NewInt(raw.ToBlock.Int64())
		}
	}

	args.Addresses = []common.Address{}

	if raw.Addresses != nil {
		// raw.Address can contain a single address or an array of addresses
		switch rawAddr := raw.Addresses.(type) {
		case []interface{}:
			for i, addr := range rawAddr {
				if strAddr, ok := addr.(string); ok {
					addr, err := decodeAddress(strAddr)
					if err != nil {
						return fmt.Errorf("invalid address at index %d: %v", i, err)
					}
					args.Addresses = append(args.Addresses, addr)
				} else {
					return fmt.Errorf("non-string address at index %d", i)
				}
			}
		case string:
			addr, err := decodeAddress(rawAddr)
			if err != nil {
				return fmt.Errorf("invalid address: %v", err)
			}
			args.Addresses = []common.Address{addr}
		default:
			return errors.New("invalid addresses in query")
		}
	}

	// topics is an array consisting of strings and/or arrays of strings.
	// JSON null values are converted to common.Hash{} and ignored by the filter manager.
	if len(raw.Topics) > 0 {
		args.Topics = make([][]common.Hash, len(raw.Topics))
		for i, t := range raw.Topics {
			switch topic := t.(type) {
			case nil:
				// ignore topic when matching logs

			case string:
				// match specific topic
				top, err := decodeTopic(topic)
				if err != nil {
					return err
				}
				args.Topics[i] = []common.Hash{top}

			case []interface{}:
				// or case e.g. [null, "topic0", "topic1"]
				for _, rawTopic := range topic {
					if rawTopic == nil {
						// null component, match all
						args.Topics[i] = nil
						break
					}
					if topic, ok := rawTopic.(string); ok {
						parsed, err := decodeTopic(topic)
						if err != nil {
							return err
						}
						args.Topics[i] = append(args.Topics[i], parsed)
					} else {
						return fmt.Errorf("invalid topic(s)")
					}
				}
			default:
				return fmt.Errorf("invalid topic(s)")
			}
		}
	}

	return nil
}

func decodeAddress(s string) (common.Address, error) {
	b, err := hexutil.Decode(s)
	if err == nil && len(b) != common.AddressLength {
		err = fmt.Errorf("hex has invalid length %d after decoding; expected %d for address", len(b), common.AddressLength)
	}
	return common.BytesToAddress(b), err
}

func decodeTopic(s string) (common.Hash, error) {
	b, err := hexutil.Decode(s)
	if err == nil && len(b) != common.HashLength {
		err = fmt.Errorf("hex has invalid length %d after decoding; expected %d for topic", len(b), common.HashLength)
	}
	return common.BytesToHash(b), err
}