forked from cosmos/iavl
-
Notifications
You must be signed in to change notification settings - Fork 0
/
versioned_tree.go
233 lines (196 loc) · 7.09 KB
/
versioned_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
package iavl
import (
"bytes"
"fmt"
"github.com/pkg/errors"
dbm "github.com/tendermint/tmlibs/db"
)
var ErrVersionDoesNotExist = fmt.Errorf("version does not exist")
// VersionedTree is a persistent tree which keeps track of versions.
type VersionedTree struct {
*orphaningTree // The current, working tree.
versions map[int64]*Tree // The previous, saved versions of the tree.
ndb *nodeDB
}
// NewVersionedTree returns a new tree with the specified cache size and datastore.
func NewVersionedTree(db dbm.DB, cacheSize int) *VersionedTree {
ndb := newNodeDB(db, cacheSize)
head := &Tree{ndb: ndb}
return &VersionedTree{
orphaningTree: newOrphaningTree(head),
versions: map[int64]*Tree{},
ndb: ndb,
}
}
// IsEmpty returns whether or not the tree has any keys. Only trees that are
// not empty can be saved.
func (tree *VersionedTree) IsEmpty() bool {
return tree.orphaningTree.Size() == 0
}
// VersionExists returns whether or not a version exists.
func (tree *VersionedTree) VersionExists(version int64) bool {
_, ok := tree.versions[version]
return ok
}
// Tree returns the current working tree.
func (tree *VersionedTree) Tree() *Tree {
return tree.orphaningTree.Tree
}
// 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 *VersionedTree) Hash() []byte {
if tree.version > 0 {
return tree.versions[tree.version].Hash()
}
return nil
}
// String returns a string representation of the tree.
func (tree *VersionedTree) String() string {
return tree.ndb.String()
}
// Set sets a key in the working tree. Nil values are not supported.
func (tree *VersionedTree) Set(key, val []byte) bool {
return tree.orphaningTree.Set(key, val)
}
// Remove removes a key from the working tree.
func (tree *VersionedTree) Remove(key []byte) ([]byte, bool) {
return tree.orphaningTree.Remove(key)
}
// Load the latest versioned tree from disk. All tree versions are loaded automatically.
func (tree *VersionedTree) Load() error {
return tree.LoadVersion(0)
}
// Load a versioned tree from disk. All tree versions are loaded automatically.
// If version is 0, the latest version is loaded.
// NOTE: This function exists for the ABCI handshake.
// TODO: Optimize this, why are we loading all the versions?!
func (tree *VersionedTree) LoadVersion(targetVersion int64) error {
roots, err := tree.ndb.getRoots()
if err != nil {
return err
}
if len(roots) == 0 {
return nil
}
// Load all roots from the database.
latestVersion := int64(0)
for version, root := range roots {
fmt.Printf("ROOTS %d %x\n", version, root)
// Construct a tree manually.
t := &Tree{}
t.ndb = tree.ndb
t.version = version
if len(root) != 0 {
t.root = tree.ndb.GetNode(root)
}
tree.versions[version] = t
if version > latestVersion &&
(targetVersion == 0 || version <= targetVersion) {
latestVersion = version
}
}
// Validate latestVersion
if !(targetVersion == 0 || latestVersion == targetVersion) {
return fmt.Errorf("Wanted to load target %v but only found up to %v",
targetVersion, latestVersion)
}
// Set the working tree to a copy of the latest.
tree.orphaningTree = newOrphaningTree(
tree.versions[latestVersion].clone(),
)
return nil
}
// Rollback resets the working tree to the latest saved version, discarding
// any unsaved modifications.
func (tree *VersionedTree) Rollback() {
if tree.version > 0 {
tree.orphaningTree = newOrphaningTree(
tree.versions[tree.version].clone(),
)
} else {
tree.orphaningTree = newOrphaningTree(&Tree{ndb: tree.ndb, version: 0})
}
}
// GetVersioned gets the value at the specified key and version.
func (tree *VersionedTree) GetVersioned(key []byte, version int64) (
index int, value []byte,
) {
if t, ok := tree.versions[version]; ok {
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 *VersionedTree) SaveVersion() ([]byte, int64, error) {
version := tree.version + 1
if _, ok := tree.versions[version]; ok {
// Same hash means idempotent. Return success.
var existingHash = tree.versions[version].Hash()
var newHash = tree.orphaningTree.Hash()
if bytes.Equal(existingHash, newHash) {
tree.orphaningTree = newOrphaningTree(tree.versions[version].clone())
return existingHash, version, nil
}
return nil, version, errors.Errorf("version %d was already saved to different hash %X (existing hash %X)",
version, newHash, existingHash)
}
// Persist version and stash to .versions.
tree.orphaningTree.SaveAs(version)
tree.versions[version] = tree.orphaningTree.Tree
// Set new working tree.
tree.orphaningTree = newOrphaningTree(tree.orphaningTree.clone())
return tree.Hash(), version, nil
}
// DeleteVersion deletes a tree version from disk. The version can then no
// longer be accessed.
func (tree *VersionedTree) 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 _, ok := tree.versions[version]; !ok {
return errors.WithStack(ErrVersionDoesNotExist)
}
tree.ndb.DeleteVersion(version)
tree.ndb.Commit()
delete(tree.versions, version)
return nil
}
// GetVersionedWithProof gets the value under the key at the specified version
// if it exists, or returns nil. A proof of existence or absence is returned
// alongside the value.
func (tree *VersionedTree) GetVersionedWithProof(key []byte, version int64) ([]byte, KeyProof, error) {
if t, ok := tree.versions[version]; ok {
return t.GetWithProof(key)
}
return nil, nil, errors.WithStack(ErrVersionDoesNotExist)
}
// GetVersionedRangeWithProof gets key/value pairs within the specified range
// and limit. To specify a descending range, swap the start and end keys.
//
// Returns a list of keys, a list of values and a proof.
func (tree *VersionedTree) GetVersionedRangeWithProof(startKey, endKey []byte, limit int, version int64) ([][]byte, [][]byte, *KeyRangeProof, error) {
if t, ok := tree.versions[version]; ok {
return t.GetRangeWithProof(startKey, endKey, limit)
}
return nil, nil, nil, errors.WithStack(ErrVersionDoesNotExist)
}
// GetVersionedFirstInRangeWithProof gets the first key/value pair in the
// specified range, with a proof.
func (tree *VersionedTree) GetVersionedFirstInRangeWithProof(startKey, endKey []byte, version int64) ([]byte, []byte, *KeyFirstInRangeProof, error) {
if t, ok := tree.versions[version]; ok {
return t.GetFirstInRangeWithProof(startKey, endKey)
}
return nil, nil, nil, errors.WithStack(ErrVersionDoesNotExist)
}
// GetVersionedLastInRangeWithProof gets the last key/value pair in the
// specified range, with a proof.
func (tree *VersionedTree) GetVersionedLastInRangeWithProof(startKey, endKey []byte, version int64) ([]byte, []byte, *KeyLastInRangeProof, error) {
if t, ok := tree.versions[version]; ok {
return t.GetLastInRangeWithProof(startKey, endKey)
}
return nil, nil, nil, errors.WithStack(ErrVersionDoesNotExist)
}