-
Notifications
You must be signed in to change notification settings - Fork 268
/
mutable_tree.go
728 lines (621 loc) · 21.7 KB
/
mutable_tree.go
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
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
package iavl
import (
"bytes"
"crypto/sha256"
"fmt"
"sort"
"github.com/pkg/errors"
dbm "github.com/tendermint/tm-db"
)
// ErrVersionDoesNotExist is returned if a requested version does not exist.
var ErrVersionDoesNotExist = errors.New("version does not exist")
// MutableTree is a persistent tree which keeps track of versions. It is not safe for concurrent
// use, and should be guarded by a Mutex or RWLock as appropriate. An immutable tree at a given
// version can be returned via GetImmutable, which is safe for concurrent access.
//
// Given and returned key/value byte slices must not be modified, since they may point to data
// located inside IAVL which would also be modified.
//
// The inner ImmutableTree should not be used directly by callers.
type MutableTree struct {
*ImmutableTree // The current, working tree.
lastSaved *ImmutableTree // The most recently saved tree.
orphans map[string]int64 // Nodes removed by changes to working tree.
versions map[int64]bool // The previous, saved versions of the tree.
allRootLoaded bool // Whether all roots are loaded or not(by LazyLoadVersion)
ndb *nodeDB
}
// NewMutableTree returns a new tree with the specified cache size and datastore.
func NewMutableTree(db dbm.DB, cacheSize int) (*MutableTree, error) {
return NewMutableTreeWithOpts(db, cacheSize, nil)
}
// NewMutableTreeWithOpts returns a new tree with the specified options.
func NewMutableTreeWithOpts(db dbm.DB, cacheSize int, opts *Options) (*MutableTree, error) {
ndb := newNodeDB(db, cacheSize, opts)
head := &ImmutableTree{ndb: ndb}
return &MutableTree{
ImmutableTree: head,
lastSaved: head.clone(),
orphans: map[string]int64{},
versions: map[int64]bool{},
allRootLoaded: false,
ndb: ndb,
}, nil
}
// IsEmpty returns whether or not the tree has any keys. Only trees that are
// not empty can be saved.
func (tree *MutableTree) IsEmpty() bool {
return tree.ImmutableTree.Size() == 0
}
// VersionExists returns whether or not a version exists.
func (tree *MutableTree) VersionExists(version int64) bool {
if tree.allRootLoaded {
return tree.versions[version]
}
has, ok := tree.versions[version]
if ok {
return has
}
has, _ = tree.ndb.HasRoot(version)
tree.versions[version] = has
return has
}
// AvailableVersions returns all available versions in ascending order
func (tree *MutableTree) AvailableVersions() []int {
res := make([]int, 0, len(tree.versions))
for i, v := range tree.versions {
if v {
res = append(res, int(i))
}
}
sort.Ints(res)
return res
}
// Hash returns the hash of the latest saved version of the tree, as returned
// by SaveVersion. If no versions have been saved, Hash returns nil.
func (tree *MutableTree) Hash() []byte {
return tree.lastSaved.Hash()
}
// WorkingHash returns the hash of the current working tree.
func (tree *MutableTree) WorkingHash() []byte {
return tree.ImmutableTree.Hash()
}
// String returns a string representation of the tree.
func (tree *MutableTree) String() string {
return tree.ndb.String()
}
// Set/Remove will orphan at most tree.Height nodes,
// balancing the tree after a Set/Remove will orphan at most 3 nodes.
func (tree *MutableTree) prepareOrphansSlice() []*Node {
return make([]*Node, 0, tree.Height()+3)
}
// Set sets a key in the working tree. Nil values are invalid. The given
// key/value byte slices must not be modified after this call, since they point
// to slices stored within IAVL. It returns true when an existing value was
// updated, while false means it was a new key.
func (tree *MutableTree) Set(key, value []byte) (updated bool) {
var orphaned []*Node
orphaned, updated = tree.set(key, value)
tree.addOrphans(orphaned)
return updated
}
// Import returns an importer for tree nodes previously exported by ImmutableTree.Export(),
// producing an identical IAVL tree. The caller must call Close() on the importer when done.
//
// version should correspond to the version that was initially exported. It must be greater than
// or equal to the highest ExportNode version number given.
//
// Import can only be called on an empty tree. It is the callers responsibility that no other
// modifications are made to the tree while importing.
func (tree *MutableTree) Import(version int64) (*Importer, error) {
return newImporter(tree, version)
}
func (tree *MutableTree) set(key []byte, value []byte) (orphans []*Node, updated bool) {
if value == nil {
panic(fmt.Sprintf("Attempt to store nil value at key '%s'", key))
}
if tree.ImmutableTree.root == nil {
tree.ImmutableTree.root = NewNode(key, value, tree.version+1)
return nil, updated
}
orphans = tree.prepareOrphansSlice()
tree.ImmutableTree.root, updated = tree.recursiveSet(tree.ImmutableTree.root, key, value, &orphans)
return orphans, updated
}
func (tree *MutableTree) recursiveSet(node *Node, key []byte, value []byte, orphans *[]*Node) (
newSelf *Node, updated bool,
) {
version := tree.version + 1
if node.isLeaf() {
switch bytes.Compare(key, node.key) {
case -1:
return &Node{
key: node.key,
height: 1,
size: 2,
leftNode: NewNode(key, value, version),
rightNode: node,
version: version,
}, false
case 1:
return &Node{
key: key,
height: 1,
size: 2,
leftNode: node,
rightNode: NewNode(key, value, version),
version: version,
}, false
default:
*orphans = append(*orphans, node)
return NewNode(key, value, version), true
}
} else {
*orphans = append(*orphans, node)
node = node.clone(version)
if bytes.Compare(key, node.key) < 0 {
node.leftNode, updated = tree.recursiveSet(node.getLeftNode(tree.ImmutableTree), key, value, orphans)
node.leftHash = nil // leftHash is yet unknown
} else {
node.rightNode, updated = tree.recursiveSet(node.getRightNode(tree.ImmutableTree), key, value, orphans)
node.rightHash = nil // rightHash is yet unknown
}
if updated {
return node, updated
}
node.calcHeightAndSize(tree.ImmutableTree)
newNode := tree.balance(node, orphans)
return newNode, updated
}
}
// Remove removes a key from the working tree. The given key byte slice should not be modified
// after this call, since it may point to data stored inside IAVL.
func (tree *MutableTree) Remove(key []byte) ([]byte, bool) {
val, orphaned, removed := tree.remove(key)
tree.addOrphans(orphaned)
return val, removed
}
// remove tries to remove a key from the tree and if removed, returns its
// value, nodes orphaned and 'true'.
func (tree *MutableTree) remove(key []byte) (value []byte, orphaned []*Node, removed bool) {
if tree.root == nil {
return nil, nil, false
}
orphaned = tree.prepareOrphansSlice()
newRootHash, newRoot, _, value := tree.recursiveRemove(tree.root, key, &orphaned)
if len(orphaned) == 0 {
return nil, nil, false
}
if newRoot == nil && newRootHash != nil {
tree.root = tree.ndb.GetNode(newRootHash)
} else {
tree.root = newRoot
}
return value, orphaned, true
}
// removes the node corresponding to the passed key and balances the tree.
// It returns:
// - the hash of the new node (or nil if the node is the one removed)
// - the node that replaces the orig. node after remove
// - new leftmost leaf key for tree after successfully removing 'key' if changed.
// - the removed value
// - the orphaned nodes.
func (tree *MutableTree) recursiveRemove(node *Node, key []byte, orphans *[]*Node) (newHash []byte, newSelf *Node, newKey []byte, newValue []byte) {
version := tree.version + 1
if node.isLeaf() {
if bytes.Equal(key, node.key) {
*orphans = append(*orphans, node)
return nil, nil, nil, node.value
}
return node.hash, node, nil, nil
}
// node.key < key; we go to the left to find the key:
if bytes.Compare(key, node.key) < 0 {
newLeftHash, newLeftNode, newKey, value := tree.recursiveRemove(node.getLeftNode(tree.ImmutableTree), key, orphans) //nolint:govet
if len(*orphans) == 0 {
return node.hash, node, nil, value
}
*orphans = append(*orphans, node)
if newLeftHash == nil && newLeftNode == nil { // left node held value, was removed
return node.rightHash, node.rightNode, node.key, value
}
newNode := node.clone(version)
newNode.leftHash, newNode.leftNode = newLeftHash, newLeftNode
newNode.calcHeightAndSize(tree.ImmutableTree)
newNode = tree.balance(newNode, orphans)
return newNode.hash, newNode, newKey, value
}
// node.key >= key; either found or look to the right:
newRightHash, newRightNode, newKey, value := tree.recursiveRemove(node.getRightNode(tree.ImmutableTree), key, orphans)
if len(*orphans) == 0 {
return node.hash, node, nil, value
}
*orphans = append(*orphans, node)
if newRightHash == nil && newRightNode == nil { // right node held value, was removed
return node.leftHash, node.leftNode, nil, value
}
newNode := node.clone(version)
newNode.rightHash, newNode.rightNode = newRightHash, newRightNode
if newKey != nil {
newNode.key = newKey
}
newNode.calcHeightAndSize(tree.ImmutableTree)
newNode = tree.balance(newNode, orphans)
return newNode.hash, newNode, nil, value
}
// Load the latest versioned tree from disk.
func (tree *MutableTree) Load() (int64, error) {
return tree.LoadVersion(int64(0))
}
// LazyLoadVersion attempts to lazy load only the specified target version
// without loading previous roots/versions. Lazy loading should be used in cases
// where only reads are expected. Any writes to a lazy loaded tree may result in
// unexpected behavior. If the targetVersion is non-positive, the latest version
// will be loaded by default. If the latest version is non-positive, this method
// performs a no-op. Otherwise, if the root does not exist, an error will be
// returned.
func (tree *MutableTree) LazyLoadVersion(targetVersion int64) (int64, error) {
latestVersion := tree.ndb.getLatestVersion()
if latestVersion < targetVersion {
return latestVersion, fmt.Errorf("wanted to load target %d but only found up to %d", targetVersion, latestVersion)
}
// no versions have been saved if the latest version is non-positive
if latestVersion <= 0 {
if targetVersion <= 0 {
return 0, nil
}
return 0, fmt.Errorf("no versions found while trying to load %v", targetVersion)
}
// default to the latest version if the targeted version is non-positive
if targetVersion <= 0 {
targetVersion = latestVersion
}
rootHash, err := tree.ndb.getRoot(targetVersion)
if err != nil {
return 0, err
}
if rootHash == nil {
return latestVersion, ErrVersionDoesNotExist
}
tree.versions[targetVersion] = true
iTree := &ImmutableTree{
ndb: tree.ndb,
version: targetVersion,
}
if len(rootHash) > 0 {
// If rootHash is empty then root of tree should be nil
// This makes `LazyLoadVersion` to do the same thing as `LoadVersion`
iTree.root = tree.ndb.GetNode(rootHash)
}
tree.orphans = map[string]int64{}
tree.ImmutableTree = iTree
tree.lastSaved = iTree.clone()
return targetVersion, nil
}
// Returns the version number of the latest version found
func (tree *MutableTree) LoadVersion(targetVersion int64) (int64, error) {
roots, err := tree.ndb.getRoots()
if err != nil {
return 0, err
}
if len(roots) == 0 {
if targetVersion <= 0 {
return 0, nil
}
return 0, fmt.Errorf("no versions found while trying to load %v", targetVersion)
}
firstVersion := int64(0)
latestVersion := int64(0)
var latestRoot []byte
for version, r := range roots {
tree.versions[version] = true
if version > latestVersion && (targetVersion == 0 || version <= targetVersion) {
latestVersion = version
latestRoot = r
}
if firstVersion == 0 || version < firstVersion {
firstVersion = version
}
}
if !(targetVersion == 0 || latestVersion == targetVersion) {
return latestVersion, fmt.Errorf("wanted to load target %v but only found up to %v",
targetVersion, latestVersion)
}
if firstVersion > 0 && firstVersion < int64(tree.ndb.opts.InitialVersion) {
return latestVersion, fmt.Errorf("initial version set to %v, but found earlier version %v",
tree.ndb.opts.InitialVersion, firstVersion)
}
t := &ImmutableTree{
ndb: tree.ndb,
version: latestVersion,
}
if len(latestRoot) != 0 {
t.root = tree.ndb.GetNode(latestRoot)
}
tree.orphans = map[string]int64{}
tree.ImmutableTree = t
tree.lastSaved = t.clone()
tree.allRootLoaded = true
return latestVersion, nil
}
// LoadVersionForOverwriting attempts to load a tree at a previously committed
// version, or the latest version below it. Any versions greater than targetVersion will be deleted.
func (tree *MutableTree) LoadVersionForOverwriting(targetVersion int64) (int64, error) {
latestVersion, err := tree.LoadVersion(targetVersion)
if err != nil {
return latestVersion, err
}
if err = tree.ndb.DeleteVersionsFrom(targetVersion + 1); err != nil {
return latestVersion, err
}
if err = tree.ndb.Commit(); err != nil {
return latestVersion, err
}
tree.ndb.resetLatestVersion(latestVersion)
for v := range tree.versions {
if v > targetVersion {
delete(tree.versions, v)
}
}
return latestVersion, nil
}
// GetImmutable loads an ImmutableTree at a given version for querying. The returned tree is
// safe for concurrent access, provided the version is not deleted, e.g. via `DeleteVersion()`.
func (tree *MutableTree) GetImmutable(version int64) (*ImmutableTree, error) {
rootHash, err := tree.ndb.getRoot(version)
if err != nil {
return nil, err
}
if rootHash == nil {
return nil, ErrVersionDoesNotExist
} else if len(rootHash) == 0 {
tree.versions[version] = true
return &ImmutableTree{
ndb: tree.ndb,
version: version,
}, nil
}
tree.versions[version] = true
return &ImmutableTree{
root: tree.ndb.GetNode(rootHash),
ndb: tree.ndb,
version: version,
}, nil
}
// Rollback resets the working tree to the latest saved version, discarding
// any unsaved modifications.
func (tree *MutableTree) Rollback() {
if tree.version > 0 {
tree.ImmutableTree = tree.lastSaved.clone()
} else {
tree.ImmutableTree = &ImmutableTree{ndb: tree.ndb, version: 0}
}
tree.orphans = map[string]int64{}
}
// GetVersioned gets the value at the specified key and version. The returned value must not be
// modified, since it may point to data stored within IAVL.
func (tree *MutableTree) GetVersioned(key []byte, version int64) (
index int64, value []byte,
) {
if tree.VersionExists(version) {
t, err := tree.GetImmutable(version)
if err != nil {
return -1, nil
}
return t.Get(key)
}
return -1, nil
}
// SaveVersion saves a new tree version to disk, based on the current state of
// the tree. Returns the hash and new version number.
func (tree *MutableTree) SaveVersion() ([]byte, int64, error) {
version := tree.version + 1
if version == 1 && tree.ndb.opts.InitialVersion > 0 {
version = int64(tree.ndb.opts.InitialVersion)
}
if tree.VersionExists(version) {
// If the version already exists, return an error as we're attempting to overwrite.
// However, the same hash means idempotent (i.e. no-op).
existingHash, err := tree.ndb.getRoot(version)
if err != nil {
return nil, version, err
}
// If the existing root hash is empty (because the tree is empty), then we need to
// compare with the hash of an empty input which is what `WorkingHash()` returns.
if len(existingHash) == 0 {
existingHash = sha256.New().Sum(nil)
}
var newHash = tree.WorkingHash()
if bytes.Equal(existingHash, newHash) {
tree.version = version
tree.ImmutableTree = tree.ImmutableTree.clone()
tree.lastSaved = tree.ImmutableTree.clone()
tree.orphans = map[string]int64{}
return existingHash, version, nil
}
return nil, version, fmt.Errorf("version %d was already saved to different hash %X (existing hash %X)", version, newHash, existingHash)
}
if tree.root == nil {
// There can still be orphans, for example if the root is the node being
// removed.
debug("SAVE EMPTY TREE %v\n", version)
tree.ndb.SaveOrphans(version, tree.orphans)
if err := tree.ndb.SaveEmptyRoot(version); err != nil {
return nil, 0, err
}
} else {
debug("SAVE TREE %v\n", version)
tree.ndb.SaveBranch(tree.root)
tree.ndb.SaveOrphans(version, tree.orphans)
if err := tree.ndb.SaveRoot(tree.root, version); err != nil {
return nil, 0, err
}
}
if err := tree.ndb.Commit(); err != nil {
return nil, version, err
}
tree.version = version
tree.versions[version] = true
// set new working tree
tree.ImmutableTree = tree.ImmutableTree.clone()
tree.lastSaved = tree.ImmutableTree.clone()
tree.orphans = map[string]int64{}
return tree.Hash(), version, nil
}
func (tree *MutableTree) deleteVersion(version int64) error {
if version <= 0 {
return errors.New("version must be greater than 0")
}
if version == tree.version {
return errors.Errorf("cannot delete latest saved version (%d)", version)
}
if !tree.VersionExists(version) {
return errors.Wrap(ErrVersionDoesNotExist, "")
}
if err := tree.ndb.DeleteVersion(version, true); err != nil {
return err
}
return nil
}
// SetInitialVersion sets the initial version of the tree, replacing Options.InitialVersion.
// It is only used during the initial SaveVersion() call for a tree with no other versions,
// and is otherwise ignored.
func (tree *MutableTree) SetInitialVersion(version uint64) {
tree.ndb.opts.InitialVersion = version
}
// DeleteVersions deletes a series of versions from the MutableTree.
// Deprecated: please use DeleteVersionsRange instead.
func (tree *MutableTree) DeleteVersions(versions ...int64) error {
debug("DELETING VERSIONS: %v\n", versions)
if len(versions) == 0 {
return nil
}
sort.Slice(versions, func(i, j int) bool {
return versions[i] < versions[j]
})
// Find ordered data and delete by interval
intervals := map[int64]int64{}
var fromVersion int64
for _, version := range versions {
if version-fromVersion != intervals[fromVersion] {
fromVersion = version
}
intervals[fromVersion]++
}
for fromVersion, sortedBatchSize := range intervals {
if err := tree.DeleteVersionsRange(fromVersion, fromVersion+sortedBatchSize); err != nil {
return err
}
}
return nil
}
// DeleteVersionsRange removes versions from an interval from the MutableTree (not inclusive).
// An error is returned if any single version has active readers.
// All writes happen in a single batch with a single commit.
func (tree *MutableTree) DeleteVersionsRange(fromVersion, toVersion int64) error {
if err := tree.ndb.DeleteVersionsRange(fromVersion, toVersion); err != nil {
return err
}
if err := tree.ndb.Commit(); err != nil {
return err
}
for version := fromVersion; version < toVersion; version++ {
delete(tree.versions, version)
}
return nil
}
// DeleteVersion deletes a tree version from disk. The version can then no
// longer be accessed.
func (tree *MutableTree) DeleteVersion(version int64) error {
debug("DELETE VERSION: %d\n", version)
if err := tree.deleteVersion(version); err != nil {
return err
}
if err := tree.ndb.Commit(); err != nil {
return err
}
delete(tree.versions, version)
return nil
}
// Rotate right and return the new node and orphan.
func (tree *MutableTree) rotateRight(node *Node) (*Node, *Node) {
version := tree.version + 1
// TODO: optimize balance & rotate.
node = node.clone(version)
orphaned := node.getLeftNode(tree.ImmutableTree)
newNode := orphaned.clone(version)
newNoderHash, newNoderCached := newNode.rightHash, newNode.rightNode
newNode.rightHash, newNode.rightNode = node.hash, node
node.leftHash, node.leftNode = newNoderHash, newNoderCached
node.calcHeightAndSize(tree.ImmutableTree)
newNode.calcHeightAndSize(tree.ImmutableTree)
return newNode, orphaned
}
// Rotate left and return the new node and orphan.
func (tree *MutableTree) rotateLeft(node *Node) (*Node, *Node) {
version := tree.version + 1
// TODO: optimize balance & rotate.
node = node.clone(version)
orphaned := node.getRightNode(tree.ImmutableTree)
newNode := orphaned.clone(version)
newNodelHash, newNodelCached := newNode.leftHash, newNode.leftNode
newNode.leftHash, newNode.leftNode = node.hash, node
node.rightHash, node.rightNode = newNodelHash, newNodelCached
node.calcHeightAndSize(tree.ImmutableTree)
newNode.calcHeightAndSize(tree.ImmutableTree)
return newNode, orphaned
}
// NOTE: assumes that node can be modified
// TODO: optimize balance & rotate
func (tree *MutableTree) balance(node *Node, orphans *[]*Node) (newSelf *Node) {
if node.persisted {
panic("Unexpected balance() call on persisted node")
}
balance := node.calcBalance(tree.ImmutableTree)
if balance > 1 {
if node.getLeftNode(tree.ImmutableTree).calcBalance(tree.ImmutableTree) >= 0 {
// Left Left Case
newNode, orphaned := tree.rotateRight(node)
*orphans = append(*orphans, orphaned)
return newNode
}
// Left Right Case
var leftOrphaned *Node
left := node.getLeftNode(tree.ImmutableTree)
node.leftHash = nil
node.leftNode, leftOrphaned = tree.rotateLeft(left)
newNode, rightOrphaned := tree.rotateRight(node)
*orphans = append(*orphans, left, leftOrphaned, rightOrphaned)
return newNode
}
if balance < -1 {
if node.getRightNode(tree.ImmutableTree).calcBalance(tree.ImmutableTree) <= 0 {
// Right Right Case
newNode, orphaned := tree.rotateLeft(node)
*orphans = append(*orphans, orphaned)
return newNode
}
// Right Left Case
var rightOrphaned *Node
right := node.getRightNode(tree.ImmutableTree)
node.rightHash = nil
node.rightNode, rightOrphaned = tree.rotateRight(right)
newNode, leftOrphaned := tree.rotateLeft(node)
*orphans = append(*orphans, right, leftOrphaned, rightOrphaned)
return newNode
}
// Nothing changed
return node
}
func (tree *MutableTree) addOrphans(orphans []*Node) {
for _, node := range orphans {
if !node.persisted {
// We don't need to orphan nodes that were never persisted.
continue
}
if len(node.hash) == 0 {
panic("Expected to find node hash, but was empty")
}
tree.orphans[string(node.hash)] = node.version
}
}