any-sync/pkg/acl/acltree/acltree.go
2022-08-02 19:28:32 +02:00

508 lines
12 KiB
Go

package acltree
import (
"context"
"errors"
"github.com/anytypeio/go-anytype-infrastructure-experiments/pkg/acl/account"
"github.com/anytypeio/go-anytype-infrastructure-experiments/pkg/acl/aclchanges/aclpb"
"github.com/anytypeio/go-anytype-infrastructure-experiments/pkg/acl/treestorage"
"github.com/anytypeio/go-anytype-infrastructure-experiments/pkg/acl/treestorage/treepb"
"sync"
)
type AddResultSummary int
const (
AddResultSummaryNothing AddResultSummary = iota
AddResultSummaryAppend
AddResultSummaryRebuild
)
type AddResult struct {
OldHeads []string
Heads []string
Added []*aclpb.RawChange
// TODO: add summary for changes
Summary AddResultSummary
}
type TreeUpdateListener interface {
Update(tree ACLTree)
Rebuild(tree ACLTree)
}
type NoOpListener struct{}
func (n NoOpListener) Update(tree ACLTree) {}
func (n NoOpListener) Rebuild(tree ACLTree) {}
type RWLocker interface {
sync.Locker
RLock()
RUnlock()
}
var ErrNoCommonSnapshot = errors.New("trees doesn't have a common snapshot")
type ACLTree interface {
RWLocker
ID() string
Header() *treepb.TreeHeader
ACLState() *ACLState
AddContent(ctx context.Context, f func(builder ChangeBuilder) error) (*aclpb.RawChange, error)
AddRawChanges(ctx context.Context, changes ...*aclpb.RawChange) (AddResult, error)
Heads() []string
Root() *Change
Iterate(func(change *Change) bool)
IterateFrom(string, func(change *Change) bool)
HasChange(string) bool
SnapshotPath() []string
ChangesAfterCommonSnapshot(snapshotPath []string) ([]*aclpb.RawChange, error)
Storage() treestorage.TreeStorage
DebugDump() (string, error)
Close() error
}
type aclTree struct {
treeStorage treestorage.TreeStorage
accountData *account.AccountData
updateListener TreeUpdateListener
id string
header *treepb.TreeHeader
fullTree *Tree
aclTreeFromStart *Tree // TODO: right now we don't use it, we can probably have only local var for now. This tree is built from start of the document
aclState *ACLState
treeBuilder *treeBuilder
aclTreeBuilder *aclTreeBuilder
aclStateBuilder *aclStateBuilder
snapshotValidator *snapshotValidator
changeBuilder *changeBuilder
sync.RWMutex
}
func BuildACLTree(
t treestorage.TreeStorage,
acc *account.AccountData,
listener TreeUpdateListener) (ACLTree, error) {
aclTreeBuilder := newACLTreeBuilder(t, acc.Decoder)
treeBuilder := newTreeBuilder(t, acc.Decoder)
snapshotValidator := newSnapshotValidator(acc.Decoder, acc) // TODO: this looks weird, change it
aclStateBuilder := newACLStateBuilder(acc.Decoder, acc)
changeBuilder := newChangeBuilder()
aclTree := &aclTree{
treeStorage: t,
accountData: acc,
fullTree: nil,
aclState: nil,
treeBuilder: treeBuilder,
aclTreeBuilder: aclTreeBuilder,
aclStateBuilder: aclStateBuilder,
snapshotValidator: snapshotValidator,
changeBuilder: changeBuilder,
updateListener: listener,
}
err := aclTree.rebuildFromStorage(false)
if err != nil {
return nil, err
}
err = aclTree.removeOrphans()
if err != nil {
return nil, err
}
err = t.SetHeads(aclTree.Heads())
if err != nil {
return nil, err
}
aclTree.id, err = t.TreeID()
if err != nil {
return nil, err
}
aclTree.header, err = t.Header()
if err != nil {
return nil, err
}
listener.Rebuild(aclTree)
return aclTree, nil
}
// TODO: this is not used for now, in future we should think about not making full tree rebuild
//func (a *aclTree) rebuildFromTree(validateSnapshot bool) (err error) {
// if validateSnapshot {
// err = a.snapshotValidator.Init(a.aclTreeFromStart)
// if err != nil {
// return err
// }
//
// valid, err := a.snapshotValidator.ValidateSnapshot(a.fullTree.root)
// if err != nil {
// return err
// }
// if !valid {
// return a.rebuildFromStorage(true)
// }
// }
//
// err = a.aclStateBuilder.Init(a.fullTree)
// if err != nil {
// return err
// }
//
// a.aclState, err = a.aclStateBuilder.Build()
// if err != nil {
// return err
// }
//
// return nil
//}
func (a *aclTree) removeOrphans() error {
// removing attached or invalid orphans
var toRemove []string
orphans, err := a.treeStorage.Orphans()
if err != nil {
return err
}
for _, orphan := range orphans {
if _, exists := a.fullTree.attached[orphan]; exists {
toRemove = append(toRemove, orphan)
}
if _, exists := a.fullTree.invalidChanges[orphan]; exists {
toRemove = append(toRemove, orphan)
}
}
return a.treeStorage.RemoveOrphans(toRemove...)
}
func (a *aclTree) rebuildFromStorage(fromStart bool) error {
a.treeBuilder.Init()
a.aclTreeBuilder.Init()
var err error
a.fullTree, err = a.treeBuilder.Build(fromStart)
if err != nil {
return err
}
// TODO: remove this from context as this is used only to validate snapshot
a.aclTreeFromStart, err = a.aclTreeBuilder.Build()
if err != nil {
return err
}
if !fromStart {
err = a.snapshotValidator.Init(a.aclTreeFromStart)
if err != nil {
return err
}
valid, err := a.snapshotValidator.ValidateSnapshot(a.fullTree.root)
if err != nil {
return err
}
if !valid {
return a.rebuildFromStorage(true)
}
}
// TODO: there is a question how we can validate not only that the full tree is built correctly
// but also that the ACL prev ids are not messed up. I think we should probably compare the resulting
// acl state with the acl state which is built in aclTreeFromStart
err = a.aclStateBuilder.Init(a.fullTree)
if err != nil {
return err
}
a.aclState, err = a.aclStateBuilder.Build()
if err != nil {
return err
}
return nil
}
func (a *aclTree) ID() string {
return a.id
}
func (a *aclTree) Header() *treepb.TreeHeader {
return a.header
}
func (a *aclTree) ACLState() *ACLState {
return a.aclState
}
func (a *aclTree) Storage() treestorage.TreeStorage {
return a.treeStorage
}
func (a *aclTree) AddContent(ctx context.Context, build func(builder ChangeBuilder) error) (*aclpb.RawChange, error) {
// TODO: add snapshot creation logic
defer func() {
// TODO: should this be called in a separate goroutine to prevent accidental cycles (tree->updater->tree)
a.updateListener.Update(a)
}()
a.changeBuilder.Init(a.aclState, a.fullTree, a.accountData)
err := build(a.changeBuilder)
if err != nil {
return nil, err
}
ch, marshalled, err := a.changeBuilder.BuildAndApply()
if err != nil {
return nil, err
}
a.fullTree.AddFast(ch)
rawCh := &aclpb.RawChange{
Payload: marshalled,
Signature: ch.Signature(),
Id: ch.Id,
}
err = a.treeStorage.AddRawChange(rawCh)
if err != nil {
return nil, err
}
err = a.treeStorage.SetHeads([]string{ch.Id})
if err != nil {
return nil, err
}
return rawCh, nil
}
func (a *aclTree) AddRawChanges(ctx context.Context, rawChanges ...*aclpb.RawChange) (AddResult, error) {
// TODO: make proper error handling, because there are a lot of corner cases where this will break
var err error
var mode Mode
var changes []*Change // TODO: = addChangesBuf[:0] ...
for _, ch := range rawChanges {
change, err := NewFromRawChange(ch)
// TODO: think what if we will have incorrect signatures on rawChanges, how everything will work
if err != nil {
continue
}
changes = append(changes, change)
}
defer func() {
if err != nil {
return
}
err = a.removeOrphans()
if err != nil {
return
}
err = a.treeStorage.SetHeads(a.fullTree.Heads())
if err != nil {
return
}
switch mode {
case Append:
a.updateListener.Update(a)
case Rebuild:
a.updateListener.Rebuild(a)
default:
break
}
}()
getAddedChanges := func() []*aclpb.RawChange {
var added []*aclpb.RawChange
for _, ch := range rawChanges {
if _, exists := a.fullTree.attached[ch.Id]; exists {
added = append(added, ch)
}
}
return added
}
for _, ch := range changes {
err = a.treeStorage.AddChange(ch)
if err != nil {
return AddResult{}, err
}
err = a.treeStorage.AddOrphans(ch.Id)
if err != nil {
return AddResult{}, err
}
}
prevHeads := a.fullTree.Heads()
mode = a.fullTree.Add(changes...)
switch mode {
case Nothing:
return AddResult{
OldHeads: prevHeads,
Heads: prevHeads,
Summary: AddResultSummaryNothing,
}, nil
case Rebuild:
err = a.rebuildFromStorage(false)
if err != nil {
return AddResult{}, err
}
return AddResult{
OldHeads: prevHeads,
Heads: a.fullTree.Heads(),
Added: getAddedChanges(),
Summary: AddResultSummaryRebuild,
}, nil
default:
// just rebuilding the state from start without reloading everything from tree storage
// as an optimization we could've started from current heads, but I didn't implement that
a.aclState, err = a.aclStateBuilder.Build()
if err != nil {
return AddResult{}, err
}
return AddResult{
OldHeads: prevHeads,
Heads: a.fullTree.Heads(),
Added: getAddedChanges(),
Summary: AddResultSummaryAppend,
}, nil
}
}
func (a *aclTree) Iterate(f func(change *Change) bool) {
a.fullTree.Iterate(a.fullTree.RootId(), f)
}
func (a *aclTree) IterateFrom(s string, f func(change *Change) bool) {
a.fullTree.Iterate(s, f)
}
func (a *aclTree) HasChange(s string) bool {
_, attachedExists := a.fullTree.attached[s]
_, unattachedExists := a.fullTree.unAttached[s]
_, invalidExists := a.fullTree.invalidChanges[s]
return attachedExists || unattachedExists || invalidExists
}
func (a *aclTree) Heads() []string {
return a.fullTree.Heads()
}
func (a *aclTree) Root() *Change {
return a.fullTree.Root()
}
func (a *aclTree) Close() error {
return nil
}
func (a *aclTree) SnapshotPath() []string {
// TODO: think about caching this
var path []string
// TODO: think that the user may have not all of the snapshots locally
currentSnapshotId := a.fullTree.RootId()
for currentSnapshotId != "" {
sn, err := a.treeBuilder.loadChange(currentSnapshotId)
if err != nil {
break
}
path = append(path, currentSnapshotId)
currentSnapshotId = sn.SnapshotId
}
return path
}
func (a *aclTree) ChangesAfterCommonSnapshot(theirPath []string) ([]*aclpb.RawChange, error) {
// TODO: think about when the clients will have their full acl tree and thus full snapshots
// but no changes after some of the snapshots
var (
isNewDocument = len(theirPath) != 0
ourPath = a.SnapshotPath()
// by default returning everything we have
commonSnapshot = ourPath[len(ourPath)-1] // TODO: root snapshot, probably it is better to have a specific method in treestorage
err error
)
// if this is non-empty request
if !isNewDocument {
commonSnapshot, err = a.commonSnapshotForTwoPaths(ourPath, theirPath)
if err != nil {
return nil, err
}
}
var rawChanges []*aclpb.RawChange
// using custom load function to skip verification step and save raw changes
load := func(id string) (*Change, error) {
raw, err := a.treeStorage.GetChange(context.Background(), id)
if err != nil {
return nil, err
}
aclChange, err := a.treeBuilder.makeUnverifiedACLChange(raw)
if err != nil {
return nil, err
}
ch := NewChange(id, aclChange)
rawChanges = append(rawChanges, raw)
return ch, nil
}
// we presume that we have everything after the common snapshot, though this may not be the case in case of clients and only ACL tree changes
_, err = a.treeBuilder.dfs(a.fullTree.Heads(), commonSnapshot, load)
if err != nil {
return nil, err
}
if isNewDocument {
_, err = load(commonSnapshot)
if err != nil {
return nil, err
}
}
return rawChanges, nil
}
func (a *aclTree) DebugDump() (string, error) {
return a.fullTree.Graph()
}
func (a *aclTree) commonSnapshotForTwoPaths(ourPath []string, theirPath []string) (string, error) {
var i int
var j int
OuterLoop:
// find starting point from the right
for i = len(ourPath) - 1; i >= 0; i-- {
for j = len(theirPath) - 1; j >= 0; j-- {
// most likely there would be only one comparison, because mostly the snapshot path will start from the root for nodes
if ourPath[i] == theirPath[j] {
break OuterLoop
}
}
}
if i < 0 || j < 0 {
return "", ErrNoCommonSnapshot
}
// find last common element of the sequence moving from right to left
for i >= 0 && j >= 0 {
if ourPath[i] == theirPath[j] {
i--
j--
}
}
return ourPath[i+1], nil
}