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any-sync/acl/acltree/treebuilder.go
2022-07-13 19:17:50 +03:00

295 lines
7.1 KiB
Go

package acltree
import (
"errors"
"fmt"
"github.com/anytypeio/go-anytype-infrastructure-experiments/acl/thread"
"github.com/anytypeio/go-anytype-infrastructure-experiments/util/keys"
//"github.com/anytypeio/go-anytype-infrastructure-experiments/pkg/lib/logging"
"github.com/anytypeio/go-anytype-infrastructure-experiments/util/slice"
"github.com/prometheus/common/log"
)
var (
//log = logging.Logger("anytype-data")
ErrEmpty = errors.New("logs empty")
)
type treeBuilder struct {
cache map[string]*Change
identityKeys map[string]keys.SigningPubKey
signingPubKeyDecoder keys.SigningPubKeyDecoder
tree *Tree
thread thread.Thread
*changeLoader
}
func newTreeBuilder(t thread.Thread, decoder keys.SigningPubKeyDecoder) *treeBuilder {
return &treeBuilder{
signingPubKeyDecoder: decoder,
thread: t,
changeLoader: newChangeLoader(
t,
decoder,
NewChange),
}
}
func (tb *treeBuilder) Init() {
tb.cache = make(map[string]*Change)
tb.identityKeys = make(map[string]keys.SigningPubKey)
tb.tree = &Tree{}
tb.changeLoader.Init(tb.cache, tb.identityKeys)
}
func (tb *treeBuilder) Build(fromStart bool) (*Tree, error) {
var headsAndOrphans []string
headsAndOrphans = append(headsAndOrphans, tb.thread.Orphans()...)
headsAndOrphans = append(headsAndOrphans, tb.thread.Heads()...)
if fromStart {
if err := tb.buildTreeFromStart(headsAndOrphans); err != nil {
return nil, fmt.Errorf("buildTree error: %v", err)
}
} else {
breakpoint, err := tb.findBreakpoint(headsAndOrphans)
if err != nil {
return nil, fmt.Errorf("findBreakpoint error: %v", err)
}
if err = tb.buildTree(headsAndOrphans, breakpoint); err != nil {
return nil, fmt.Errorf("buildTree error: %v", err)
}
}
tb.cache = nil
return tb.tree, nil
}
func (tb *treeBuilder) buildTreeFromStart(heads []string) (err error) {
changes, root, err := tb.dfsFromStart(heads)
if err != nil {
return err
}
tb.tree.AddFast(root)
tb.tree.AddFast(changes...)
return
}
func (tb *treeBuilder) dfsFromStart(heads []string) (buf []*Change, root *Change, err error) {
var possibleRoots []*Change
stack := make([]string, len(heads), len(heads)*2)
copy(stack, heads)
buf = make([]*Change, 0, len(stack)*2)
uniqMap := make(map[string]struct{})
for len(stack) > 0 {
id := stack[len(stack)-1]
stack = stack[:len(stack)-1]
if _, exists := uniqMap[id]; exists {
continue
}
ch, err := tb.loadChange(id)
if err != nil {
continue
}
uniqMap[id] = struct{}{}
buf = append(buf, ch)
for _, prev := range ch.PreviousIds {
stack = append(stack, prev)
}
if len(ch.PreviousIds) == 0 {
possibleRoots = append(possibleRoots, ch)
}
}
header := tb.thread.Header()
for _, r := range possibleRoots {
if r.Id == header.FirstChangeId {
return buf, r, nil
}
}
return nil, nil, fmt.Errorf("could not find root change")
}
func (tb *treeBuilder) buildTree(heads []string, breakpoint string) (err error) {
ch, err := tb.loadChange(breakpoint)
if err != nil {
return
}
tb.tree.AddFast(ch)
changes, err := tb.dfs(heads, breakpoint)
tb.tree.AddFast(changes...)
return
}
func (tb *treeBuilder) dfs(heads []string, breakpoint string) (buf []*Change, err error) {
stack := make([]string, len(heads), len(heads)*2)
copy(stack, heads)
buf = make([]*Change, 0, len(stack)*2)
uniqMap := map[string]struct{}{breakpoint: {}}
for len(stack) > 0 {
id := stack[len(stack)-1]
stack = stack[:len(stack)-1]
if _, exists := uniqMap[id]; exists {
continue
}
ch, err := tb.loadChange(id)
if err != nil {
continue
}
uniqMap[id] = struct{}{}
buf = append(buf, ch)
for _, prev := range ch.PreviousIds {
stack = append(stack, prev)
}
}
return buf, nil
}
func (tb *treeBuilder) findBreakpoint(heads []string) (breakpoint string, err error) {
var (
ch *Change
snapshotIds []string
)
for _, head := range heads {
if ch, err = tb.loadChange(head); err != nil {
return
}
shId := ch.SnapshotId
if ch.IsSnapshot {
shId = ch.Id
}
if slice.FindPos(snapshotIds, shId) == -1 {
snapshotIds = append(snapshotIds, shId)
}
}
return tb.findCommonSnapshot(snapshotIds)
}
func (tb *treeBuilder) findCommonSnapshot(snapshotIds []string) (snapshotId string, err error) {
if len(snapshotIds) == 1 {
return snapshotIds[0], nil
} else if len(snapshotIds) == 0 {
return "", fmt.Errorf("snapshots not found")
}
for len(snapshotIds) > 1 {
l := len(snapshotIds)
shId, e := tb.findCommonForTwoSnapshots(snapshotIds[l-2], snapshotIds[l-1])
if e != nil {
return "", e
}
snapshotIds[l-2] = shId
snapshotIds = snapshotIds[:l-1]
}
return snapshotIds[0], nil
}
func (tb *treeBuilder) findCommonForTwoSnapshots(s1, s2 string) (s string, err error) {
// fast cases
if s1 == s2 {
return s1, nil
}
ch1, err := tb.loadChange(s1)
if err != nil {
return "", err
}
if ch1.SnapshotId == s2 {
return s2, nil
}
ch2, err := tb.loadChange(s2)
if err != nil {
return "", err
}
if ch2.SnapshotId == s1 {
return s1, nil
}
if ch1.SnapshotId == ch2.SnapshotId && ch1.SnapshotId != "" {
return ch1.SnapshotId, nil
}
// traverse
var t1 = make([]string, 0, 5)
var t2 = make([]string, 0, 5)
t1 = append(t1, ch1.Id, ch1.SnapshotId)
t2 = append(t2, ch2.Id, ch2.SnapshotId)
for {
lid1 := t1[len(t1)-1]
if lid1 != "" {
l1, e := tb.loadChange(lid1)
if e != nil {
return "", e
}
if l1.SnapshotId != "" {
if slice.FindPos(t2, l1.SnapshotId) != -1 {
return l1.SnapshotId, nil
}
}
t1 = append(t1, l1.SnapshotId)
}
lid2 := t2[len(t2)-1]
if lid2 != "" {
l2, e := tb.loadChange(t2[len(t2)-1])
if e != nil {
return "", e
}
if l2.SnapshotId != "" {
if slice.FindPos(t1, l2.SnapshotId) != -1 {
return l2.SnapshotId, nil
}
}
t2 = append(t2, l2.SnapshotId)
}
if lid1 == "" && lid2 == "" {
break
}
}
log.Warnf("changes build Tree: possible versions split")
// prefer not first snapshot
if len(ch1.PreviousIds) == 0 && len(ch2.PreviousIds) > 0 {
log.Warnf("changes build Tree: prefer %s(%d prevIds) over %s(%d prevIds)", s2, len(ch2.PreviousIds), s1, len(ch1.PreviousIds))
return s2, nil
} else if len(ch1.PreviousIds) > 0 && len(ch2.PreviousIds) == 0 {
log.Warnf("changes build Tree: prefer %s(%d prevIds) over %s(%d prevIds)", s1, len(ch1.PreviousIds), s2, len(ch2.PreviousIds))
return s1, nil
}
isEmptySnapshot := func(ch *Change) bool {
// TODO: add more sophisticated checks in Change for snapshots
return !ch.IsSnapshot
}
// TODO: can we even have empty snapshots?
// prefer not empty snapshot
if isEmptySnapshot(ch1) && !isEmptySnapshot(ch2) {
log.Warnf("changes build Tree: prefer %s(not empty) over %s(empty)", s2, s1)
return s2, nil
} else if isEmptySnapshot(ch2) && !isEmptySnapshot(ch1) {
log.Warnf("changes build Tree: prefer %s(not empty) over %s(empty)", s1, s2)
return s1, nil
}
// TODO: add virtual change mechanics
// unexpected behavior - just return lesser id
if s1 < s2 {
log.Warnf("changes build Tree: prefer %s (%s<%s)", s1, s1, s2)
return s1, nil
}
log.Warnf("changes build Tree: prefer %s (%s<%s)", s2, s2, s1)
return s2, nil
}