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-rw-r--r--entity/dag/common_test.go137
-rw-r--r--entity/dag/entity.go389
-rw-r--r--entity/dag/entity_actions.go227
-rw-r--r--entity/dag/entity_test.go117
-rw-r--r--entity/dag/operation.go31
-rw-r--r--entity/dag/operation_pack.go294
-rw-r--r--entity/dag/operation_pack_test.go44
7 files changed, 1239 insertions, 0 deletions
diff --git a/entity/dag/common_test.go b/entity/dag/common_test.go
new file mode 100644
index 00000000..29f1279e
--- /dev/null
+++ b/entity/dag/common_test.go
@@ -0,0 +1,137 @@
+package dag
+
+import (
+ "encoding/json"
+ "fmt"
+
+ "github.com/MichaelMure/git-bug/entity"
+ "github.com/MichaelMure/git-bug/identity"
+ "github.com/MichaelMure/git-bug/repository"
+)
+
+// This file contains an example dummy entity to be used in the tests
+
+/*
+ Operations
+*/
+
+type op1 struct {
+ author identity.Interface
+
+ OperationType int `json:"type"`
+ Field1 string `json:"field_1"`
+}
+
+func newOp1(author identity.Interface, field1 string) *op1 {
+ return &op1{author: author, OperationType: 1, Field1: field1}
+}
+
+func (o op1) Id() entity.Id {
+ data, _ := json.Marshal(o)
+ return entity.DeriveId(data)
+}
+
+func (o op1) Author() identity.Interface {
+ return o.author
+}
+
+func (o op1) Validate() error { return nil }
+
+type op2 struct {
+ author identity.Interface
+
+ OperationType int `json:"type"`
+ Field2 string `json:"field_2"`
+}
+
+func newOp2(author identity.Interface, field2 string) *op2 {
+ return &op2{author: author, OperationType: 2, Field2: field2}
+}
+
+func (o op2) Id() entity.Id {
+ data, _ := json.Marshal(o)
+ return entity.DeriveId(data)
+}
+
+func (o op2) Author() identity.Interface {
+ return o.author
+}
+
+func (o op2) Validate() error { return nil }
+
+func unmarshaler(author identity.Interface, raw json.RawMessage) (Operation, error) {
+ var t struct {
+ OperationType int `json:"type"`
+ }
+
+ if err := json.Unmarshal(raw, &t); err != nil {
+ return nil, err
+ }
+
+ switch t.OperationType {
+ case 1:
+ op := &op1{}
+ err := json.Unmarshal(raw, &op)
+ op.author = author
+ return op, err
+ case 2:
+ op := &op2{}
+ err := json.Unmarshal(raw, &op)
+ op.author = author
+ return op, err
+ default:
+ return nil, fmt.Errorf("unknown operation type %v", t.OperationType)
+ }
+}
+
+/*
+ Identities + repo + definition
+*/
+
+func makeTestContext() (repository.ClockedRepo, identity.Interface, identity.Interface, Definition) {
+ repo := repository.NewMockRepo()
+
+ id1, err := identity.NewIdentity(repo, "name1", "email1")
+ if err != nil {
+ panic(err)
+ }
+ err = id1.Commit(repo)
+ if err != nil {
+ panic(err)
+ }
+ id2, err := identity.NewIdentity(repo, "name2", "email2")
+ if err != nil {
+ panic(err)
+ }
+ err = id2.Commit(repo)
+ if err != nil {
+ panic(err)
+ }
+
+ resolver := identityResolverFunc(func(id entity.Id) (identity.Interface, error) {
+ switch id {
+ case id1.Id():
+ return id1, nil
+ case id2.Id():
+ return id2, nil
+ default:
+ return nil, identity.ErrIdentityNotExist
+ }
+ })
+
+ def := Definition{
+ typename: "foo",
+ namespace: "foos",
+ operationUnmarshaler: unmarshaler,
+ identityResolver: resolver,
+ formatVersion: 1,
+ }
+
+ return repo, id1, id2, def
+}
+
+type identityResolverFunc func(id entity.Id) (identity.Interface, error)
+
+func (fn identityResolverFunc) ResolveIdentity(id entity.Id) (identity.Interface, error) {
+ return fn(id)
+}
diff --git a/entity/dag/entity.go b/entity/dag/entity.go
new file mode 100644
index 00000000..78347fa0
--- /dev/null
+++ b/entity/dag/entity.go
@@ -0,0 +1,389 @@
+// Package dag contains the base common code to define an entity stored
+// in a chain of git objects, supporting actions like Push, Pull and Merge.
+package dag
+
+import (
+ "encoding/json"
+ "fmt"
+ "sort"
+
+ "github.com/pkg/errors"
+
+ "github.com/MichaelMure/git-bug/entity"
+ "github.com/MichaelMure/git-bug/identity"
+ "github.com/MichaelMure/git-bug/repository"
+ "github.com/MichaelMure/git-bug/util/lamport"
+)
+
+const refsPattern = "refs/%s/%s"
+const creationClockPattern = "%s-create"
+const editClockPattern = "%s-edit"
+
+// Definition hold the details defining one specialization of an Entity.
+type Definition struct {
+ // the name of the entity (bug, pull-request, ...)
+ typename string
+ // the namespace in git (bugs, prs, ...)
+ namespace string
+ // a function decoding a JSON message into an Operation
+ operationUnmarshaler func(author identity.Interface, raw json.RawMessage) (Operation, error)
+ // a function loading an identity.Identity from its Id
+ identityResolver identity.Resolver
+ // the expected format version number, that can be used for data migration/upgrade
+ formatVersion uint
+}
+
+// Entity is a data structure stored in a chain of git objects, supporting actions like Push, Pull and Merge.
+type Entity struct {
+ Definition
+
+ // operations that are already stored in the repository
+ ops []Operation
+ // operations not yet stored in the repository
+ staging []Operation
+
+ // TODO: add here createTime and editTime
+
+ // // TODO: doesn't seems to actually be useful over the topological sort ? Timestamp can be generated from graph depth
+ // // TODO: maybe EditTime is better because it could spread ops in consecutive groups on the logical timeline --> avoid interleaving
+ // packClock lamport.Clock
+ lastCommit repository.Hash
+}
+
+// New create an empty Entity
+func New(definition Definition) *Entity {
+ return &Entity{
+ Definition: definition,
+ // packClock: lamport.NewMemClock(),
+ }
+}
+
+// Read will read and decode a stored Entity from a repository
+func Read(def Definition, repo repository.ClockedRepo, id entity.Id) (*Entity, error) {
+ if err := id.Validate(); err != nil {
+ return nil, errors.Wrap(err, "invalid id")
+ }
+
+ ref := fmt.Sprintf("refs/%s/%s", def.namespace, id.String())
+
+ return read(def, repo, ref)
+}
+
+// read fetch from git and decode an Entity at an arbitrary git reference.
+func read(def Definition, repo repository.ClockedRepo, ref string) (*Entity, error) {
+ rootHash, err := repo.ResolveRef(ref)
+ if err != nil {
+ return nil, err
+ }
+
+ // Perform a depth-first search to get a topological order of the DAG where we discover the
+ // parents commit and go back in time up to the chronological root
+
+ stack := make([]repository.Hash, 0, 32)
+ visited := make(map[repository.Hash]struct{})
+ DFSOrder := make([]repository.Commit, 0, 32)
+
+ stack = append(stack, rootHash)
+
+ for len(stack) > 0 {
+ // pop
+ hash := stack[len(stack)-1]
+ stack = stack[:len(stack)-1]
+
+ if _, ok := visited[hash]; ok {
+ continue
+ }
+
+ // mark as visited
+ visited[hash] = struct{}{}
+
+ commit, err := repo.ReadCommit(hash)
+ if err != nil {
+ return nil, err
+ }
+
+ DFSOrder = append(DFSOrder, commit)
+
+ for _, parent := range commit.Parents {
+ stack = append(stack, parent)
+ }
+ }
+
+ // Now, we can reverse this topological order and read the commits in an order where
+ // we are sure to have read all the chronological ancestors when we read a commit.
+
+ // Next step is to:
+ // 1) read the operationPacks
+ // 2) make sure that the clocks causality respect the DAG topology.
+
+ oppMap := make(map[repository.Hash]*operationPack)
+ var opsCount int
+ // var packClock = lamport.NewMemClock()
+
+ for i := len(DFSOrder) - 1; i >= 0; i-- {
+ commit := DFSOrder[i]
+ isFirstCommit := i == len(DFSOrder)-1
+ isMerge := len(commit.Parents) > 1
+
+ // Verify DAG structure: single chronological root, so only the root
+ // can have no parents. Said otherwise, the DAG need to have exactly
+ // one leaf.
+ if !isFirstCommit && len(commit.Parents) == 0 {
+ return nil, fmt.Errorf("multiple leafs in the entity DAG")
+ }
+
+ opp, err := readOperationPack(def, repo, commit)
+ if err != nil {
+ return nil, err
+ }
+
+ err = opp.Validate()
+ if err != nil {
+ return nil, err
+ }
+
+ // Check that the create lamport clock is set (not checked in Validate() as it's optional)
+ if isFirstCommit && opp.CreateTime <= 0 {
+ return nil, fmt.Errorf("creation lamport time not set")
+ }
+
+ // make sure that the lamport clocks causality match the DAG topology
+ for _, parentHash := range commit.Parents {
+ parentPack, ok := oppMap[parentHash]
+ if !ok {
+ panic("DFS failed")
+ }
+
+ if parentPack.EditTime >= opp.EditTime {
+ return nil, fmt.Errorf("lamport clock ordering doesn't match the DAG")
+ }
+
+ // to avoid an attack where clocks are pushed toward the uint64 rollover, make sure
+ // that the clocks don't jump too far in the future
+ // we ignore merge commits here to allow merging after a loooong time without breaking anything,
+ // as long as there is one valid chain of small hops, it's fine.
+ if !isMerge && opp.EditTime-parentPack.EditTime > 1_000_000 {
+ return nil, fmt.Errorf("lamport clock jumping too far in the future, likely an attack")
+ }
+
+ // TODO: PackTime is not checked
+ }
+
+ oppMap[commit.Hash] = opp
+ opsCount += len(opp.Operations)
+ }
+
+ // The clocks are fine, we witness them
+ for _, opp := range oppMap {
+ err = repo.Witness(fmt.Sprintf(creationClockPattern, def.namespace), opp.CreateTime)
+ if err != nil {
+ return nil, err
+ }
+ err = repo.Witness(fmt.Sprintf(editClockPattern, def.namespace), opp.EditTime)
+ if err != nil {
+ return nil, err
+ }
+ // err = packClock.Witness(opp.PackTime)
+ // if err != nil {
+ // return nil, err
+ // }
+ }
+
+ // Now that we know that the topological order and clocks are fine, we order the operationPacks
+ // based on the logical clocks, entirely ignoring the DAG topology
+
+ oppSlice := make([]*operationPack, 0, len(oppMap))
+ for _, pack := range oppMap {
+ oppSlice = append(oppSlice, pack)
+ }
+ sort.Slice(oppSlice, func(i, j int) bool {
+ // Primary ordering with the dedicated "pack" Lamport time that encode causality
+ // within the entity
+ // if oppSlice[i].PackTime != oppSlice[j].PackTime {
+ // return oppSlice[i].PackTime < oppSlice[i].PackTime
+ // }
+ // We have equal PackTime, which means we had a concurrent edition. We can't tell which exactly
+ // came first. As a secondary arbitrary ordering, we can use the EditTime. It's unlikely to be
+ // enough but it can give us an edge to approach what really happened.
+ if oppSlice[i].EditTime != oppSlice[j].EditTime {
+ return oppSlice[i].EditTime < oppSlice[j].EditTime
+ }
+ // Well, what now? We still need a total ordering and the most stable possible.
+ // As a last resort, we can order based on a hash of the serialized Operations in the
+ // operationPack. It doesn't carry much meaning but it's unbiased and hard to abuse.
+ // This is a lexicographic ordering on the stringified ID.
+ return oppSlice[i].Id() < oppSlice[j].Id()
+ })
+
+ // Now that we ordered the operationPacks, we have the order of the Operations
+
+ ops := make([]Operation, 0, opsCount)
+ for _, pack := range oppSlice {
+ for _, operation := range pack.Operations {
+ ops = append(ops, operation)
+ }
+ }
+
+ return &Entity{
+ Definition: def,
+ ops: ops,
+ // packClock: packClock,
+ lastCommit: rootHash,
+ }, nil
+}
+
+// Id return the Entity identifier
+func (e *Entity) Id() entity.Id {
+ // id is the id of the first operation
+ return e.FirstOp().Id()
+}
+
+// Validate check if the Entity data is valid
+func (e *Entity) Validate() error {
+ // non-empty
+ if len(e.ops) == 0 && len(e.staging) == 0 {
+ return fmt.Errorf("entity has no operations")
+ }
+
+ // check if each operations are valid
+ for _, op := range e.ops {
+ if err := op.Validate(); err != nil {
+ return err
+ }
+ }
+
+ // check if staging is valid if needed
+ for _, op := range e.staging {
+ if err := op.Validate(); err != nil {
+ return err
+ }
+ }
+
+ // Check that there is no colliding operation's ID
+ ids := make(map[entity.Id]struct{})
+ for _, op := range e.Operations() {
+ if _, ok := ids[op.Id()]; ok {
+ return fmt.Errorf("id collision: %s", op.Id())
+ }
+ ids[op.Id()] = struct{}{}
+ }
+
+ return nil
+}
+
+// Operations return the ordered operations
+func (e *Entity) Operations() []Operation {
+ return append(e.ops, e.staging...)
+}
+
+// FirstOp lookup for the very first operation of the Entity
+func (e *Entity) FirstOp() Operation {
+ for _, op := range e.ops {
+ return op
+ }
+ for _, op := range e.staging {
+ return op
+ }
+ return nil
+}
+
+// LastOp lookup for the very last operation of the Entity
+func (e *Entity) LastOp() Operation {
+ if len(e.staging) > 0 {
+ return e.staging[len(e.staging)-1]
+ }
+ if len(e.ops) > 0 {
+ return e.ops[len(e.ops)-1]
+ }
+ return nil
+}
+
+// Append add a new Operation to the Entity
+func (e *Entity) Append(op Operation) {
+ e.staging = append(e.staging, op)
+}
+
+// NeedCommit indicate if the in-memory state changed and need to be commit in the repository
+func (e *Entity) NeedCommit() bool {
+ return len(e.staging) > 0
+}
+
+// CommitAdNeeded execute a Commit only if necessary. This function is useful to avoid getting an error if the Entity
+// is already in sync with the repository.
+func (e *Entity) CommitAdNeeded(repo repository.ClockedRepo) error {
+ if e.NeedCommit() {
+ return e.Commit(repo)
+ }
+ return nil
+}
+
+// Commit write the appended operations in the repository
+// TODO: support commit signature
+func (e *Entity) Commit(repo repository.ClockedRepo) error {
+ if !e.NeedCommit() {
+ return fmt.Errorf("can't commit an entity with no pending operation")
+ }
+
+ if err := e.Validate(); err != nil {
+ return errors.Wrapf(err, "can't commit a %s with invalid data", e.Definition.typename)
+ }
+
+ var author identity.Interface
+ for _, op := range e.staging {
+ if author != nil && op.Author() != author {
+ return fmt.Errorf("operations with different author")
+ }
+ author = op.Author()
+ }
+
+ // increment the various clocks for this new operationPack
+ // packTime, err := e.packClock.Increment()
+ // if err != nil {
+ // return err
+ // }
+ editTime, err := repo.Increment(fmt.Sprintf(editClockPattern, e.namespace))
+ if err != nil {
+ return err
+ }
+ var creationTime lamport.Time
+ if e.lastCommit == "" {
+ creationTime, err = repo.Increment(fmt.Sprintf(creationClockPattern, e.namespace))
+ if err != nil {
+ return err
+ }
+ }
+
+ opp := &operationPack{
+ Author: author,
+ Operations: e.staging,
+ CreateTime: creationTime,
+ EditTime: editTime,
+ // PackTime: packTime,
+ }
+
+ treeHash, err := opp.Write(e.Definition, repo)
+ if err != nil {
+ return err
+ }
+
+ // Write a Git commit referencing the tree, with the previous commit as parent
+ var commitHash repository.Hash
+ if e.lastCommit != "" {
+ commitHash, err = repo.StoreCommit(treeHash, e.lastCommit)
+ } else {
+ commitHash, err = repo.StoreCommit(treeHash)
+ }
+ if err != nil {
+ return err
+ }
+
+ e.lastCommit = commitHash
+ e.ops = append(e.ops, e.staging...)
+ e.staging = nil
+
+ // Create or update the Git reference for this entity
+ // When pushing later, the remote will ensure that this ref update
+ // is fast-forward, that is no data has been overwritten.
+ ref := fmt.Sprintf(refsPattern, e.namespace, e.Id().String())
+ return repo.UpdateRef(ref, commitHash)
+}
diff --git a/entity/dag/entity_actions.go b/entity/dag/entity_actions.go
new file mode 100644
index 00000000..8dcf91e6
--- /dev/null
+++ b/entity/dag/entity_actions.go
@@ -0,0 +1,227 @@
+package dag
+
+import (
+ "fmt"
+
+ "github.com/pkg/errors"
+
+ "github.com/MichaelMure/git-bug/entity"
+ "github.com/MichaelMure/git-bug/repository"
+)
+
+func ListLocalIds(typename string, repo repository.RepoData) ([]entity.Id, error) {
+ refs, err := repo.ListRefs(fmt.Sprintf("refs/%s/", typename))
+ if err != nil {
+ return nil, err
+ }
+ return entity.RefsToIds(refs), nil
+}
+
+// Fetch retrieve updates from a remote
+// This does not change the local entity state
+func Fetch(def Definition, repo repository.Repo, remote string) (string, error) {
+ // "refs/<entity>/*:refs/remotes/<remote>/<entity>/*"
+ fetchRefSpec := fmt.Sprintf("refs/%s/*:refs/remotes/%s/%s/*",
+ def.namespace, remote, def.namespace)
+
+ return repo.FetchRefs(remote, fetchRefSpec)
+}
+
+// Push update a remote with the local changes
+func Push(def Definition, repo repository.Repo, remote string) (string, error) {
+ // "refs/<entity>/*:refs/<entity>/*"
+ refspec := fmt.Sprintf("refs/%s/*:refs/%s/*",
+ def.namespace, def.namespace)
+
+ return repo.PushRefs(remote, refspec)
+}
+
+// Pull will do a Fetch + MergeAll
+// Contrary to MergeAll, this function will return an error if a merge fail.
+func Pull(def Definition, repo repository.ClockedRepo, remote string) error {
+ _, err := Fetch(def, repo, remote)
+ if err != nil {
+ return err
+ }
+
+ for merge := range MergeAll(def, repo, remote) {
+ if merge.Err != nil {
+ return merge.Err
+ }
+ if merge.Status == entity.MergeStatusInvalid {
+ return errors.Errorf("merge failure: %s", merge.Reason)
+ }
+ }
+
+ return nil
+}
+
+func MergeAll(def Definition, repo repository.ClockedRepo, remote string) <-chan entity.MergeResult {
+ out := make(chan entity.MergeResult)
+
+ // no caching for the merge, we load everything from git even if that means multiple
+ // copy of the same entity in memory. The cache layer will intercept the results to
+ // invalidate entities if necessary.
+
+ go func() {
+ defer close(out)
+
+ remoteRefSpec := fmt.Sprintf("refs/remotes/%s/%s/", remote, def.namespace)
+ remoteRefs, err := repo.ListRefs(remoteRefSpec)
+ if err != nil {
+ out <- entity.MergeResult{Err: err}
+ return
+ }
+
+ for _, remoteRef := range remoteRefs {
+ out <- merge(def, repo, remoteRef)
+ }
+ }()
+
+ return out
+}
+
+func merge(def Definition, repo repository.ClockedRepo, remoteRef string) entity.MergeResult {
+ id := entity.RefToId(remoteRef)
+
+ if err := id.Validate(); err != nil {
+ return entity.NewMergeInvalidStatus(id, errors.Wrap(err, "invalid ref").Error())
+ }
+
+ remoteEntity, err := read(def, repo, remoteRef)
+ if err != nil {
+ return entity.NewMergeInvalidStatus(id,
+ errors.Wrapf(err, "remote %s is not readable", def.typename).Error())
+ }
+
+ // Check for error in remote data
+ if err := remoteEntity.Validate(); err != nil {
+ return entity.NewMergeInvalidStatus(id,
+ errors.Wrapf(err, "remote %s data is invalid", def.typename).Error())
+ }
+
+ localRef := fmt.Sprintf("refs/%s/%s", def.namespace, id.String())
+
+ localExist, err := repo.RefExist(localRef)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ // the bug is not local yet, simply create the reference
+ if !localExist {
+ err := repo.CopyRef(remoteRef, localRef)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ return entity.NewMergeStatus(entity.MergeStatusNew, id, remoteEntity)
+ }
+
+ // var updated bool
+ // err = repo.MergeRef(localRef, remoteRef, func() repository.Hash {
+ // updated = true
+ //
+ // })
+ // if err != nil {
+ // return entity.NewMergeError(err, id)
+ // }
+ //
+ // if updated {
+ // return entity.NewMergeStatus(entity.MergeStatusUpdated, id, )
+ // } else {
+ // return entity.NewMergeStatus(entity.MergeStatusNothing, id, )
+ // }
+
+ localCommit, err := repo.ResolveRef(localRef)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ remoteCommit, err := repo.ResolveRef(remoteRef)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ if localCommit == remoteCommit {
+ // nothing to merge
+ return entity.NewMergeStatus(entity.MergeStatusNothing, id, remoteEntity)
+ }
+
+ // fast-forward is possible if otherRef include ref
+
+ remoteCommits, err := repo.ListCommits(remoteRef)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ fastForwardPossible := false
+ for _, hash := range remoteCommits {
+ if hash == localCommit {
+ fastForwardPossible = true
+ break
+ }
+ }
+
+ if fastForwardPossible {
+ err = repo.UpdateRef(localRef, remoteCommit)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+ return entity.NewMergeStatus(entity.MergeStatusUpdated, id, remoteEntity)
+ }
+
+ // fast-forward is not possible, we need to create a merge commit
+ // For simplicity when reading and to have clocks that record this change, we store
+ // an empty operationPack.
+ // First step is to collect those clocks.
+
+ localEntity, err := read(def, repo, localRef)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ // err = localEntity.packClock.Witness(remoteEntity.packClock.Time())
+ // if err != nil {
+ // return entity.NewMergeError(err, id)
+ // }
+ //
+ // packTime, err := localEntity.packClock.Increment()
+ // if err != nil {
+ // return entity.NewMergeError(err, id)
+ // }
+
+ editTime, err := repo.Increment(fmt.Sprintf(editClockPattern, def.namespace))
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ opp := &operationPack{
+ Operations: nil,
+ CreateTime: 0,
+ EditTime: editTime,
+ // PackTime: packTime,
+ }
+
+ treeHash, err := opp.Write(def, repo)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ // Create the merge commit with two parents
+ newHash, err := repo.StoreCommit(treeHash, localCommit, remoteCommit)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ // finally update the ref
+ err = repo.UpdateRef(localRef, newHash)
+ if err != nil {
+ return entity.NewMergeError(err, id)
+ }
+
+ return entity.NewMergeStatus(entity.MergeStatusUpdated, id, localEntity)
+}
+
+func Remove() error {
+ panic("")
+}
diff --git a/entity/dag/entity_test.go b/entity/dag/entity_test.go
new file mode 100644
index 00000000..c5c83567
--- /dev/null
+++ b/entity/dag/entity_test.go
@@ -0,0 +1,117 @@
+package dag
+
+import (
+ "testing"
+
+ "github.com/stretchr/testify/require"
+)
+
+func TestWriteRead(t *testing.T) {
+ repo, id1, id2, def := makeTestContext()
+
+ entity := New(def)
+ require.False(t, entity.NeedCommit())
+
+ entity.Append(newOp1(id1, "foo"))
+ entity.Append(newOp2(id1, "bar"))
+
+ require.True(t, entity.NeedCommit())
+ require.NoError(t, entity.CommitAdNeeded(repo))
+ require.False(t, entity.NeedCommit())
+
+ entity.Append(newOp2(id2, "foobar"))
+ require.True(t, entity.NeedCommit())
+ require.NoError(t, entity.CommitAdNeeded(repo))
+ require.False(t, entity.NeedCommit())
+
+ read, err := Read(def, repo, entity.Id())
+ require.NoError(t, err)
+
+ assertEqualEntities(t, entity, read)
+}
+
+func assertEqualEntities(t *testing.T, a, b *Entity) {
+ // testify doesn't support comparing functions and systematically fail if they are not nil
+ // so we have to set them to nil temporarily
+
+ backOpUnA := a.Definition.operationUnmarshaler
+ backOpUnB := b.Definition.operationUnmarshaler
+
+ a.Definition.operationUnmarshaler = nil
+ b.Definition.operationUnmarshaler = nil
+
+ backIdResA := a.Definition.identityResolver
+ backIdResB := b.Definition.identityResolver
+
+ a.Definition.identityResolver = nil
+ b.Definition.identityResolver = nil
+
+ defer func() {
+ a.Definition.operationUnmarshaler = backOpUnA
+ b.Definition.operationUnmarshaler = backOpUnB
+ a.Definition.identityResolver = backIdResA
+ b.Definition.identityResolver = backIdResB
+ }()
+
+ require.Equal(t, a, b)
+}
+
+// // Merge
+//
+// merge1 := makeCommit(t, repo)
+// merge1 = makeCommit(t, repo, merge1)
+// err = repo.UpdateRef("merge1", merge1)
+// require.NoError(t, err)
+//
+// err = repo.UpdateRef("merge2", merge1)
+// require.NoError(t, err)
+//
+// // identical merge
+// err = repo.MergeRef("merge1", "merge2")
+// require.NoError(t, err)
+//
+// refMerge1, err := repo.ResolveRef("merge1")
+// require.NoError(t, err)
+// require.Equal(t, merge1, refMerge1)
+// refMerge2, err := repo.ResolveRef("merge2")
+// require.NoError(t, err)
+// require.Equal(t, merge1, refMerge2)
+//
+// // fast-forward merge
+// merge2 := makeCommit(t, repo, merge1)
+// merge2 = makeCommit(t, repo, merge2)
+//
+// err = repo.UpdateRef("merge2", merge2)
+// require.NoError(t, err)
+//
+// err = repo.MergeRef("merge1", "merge2")
+// require.NoError(t, err)
+//
+// refMerge1, err = repo.ResolveRef("merge1")
+// require.NoError(t, err)
+// require.Equal(t, merge2, refMerge1)
+// refMerge2, err = repo.ResolveRef("merge2")
+// require.NoError(t, err)
+// require.Equal(t, merge2, refMerge2)
+//
+// // merge commit
+// merge1 = makeCommit(t, repo, merge1)
+// err = repo.UpdateRef("merge1", merge1)
+// require.NoError(t, err)
+//
+// merge2 = makeCommit(t, repo, merge2)
+// err = repo.UpdateRef("merge2", merge2)
+// require.NoError(t, err)
+//
+// err = repo.MergeRef("merge1", "merge2")
+// require.NoError(t, err)
+//
+// refMerge1, err = repo.ResolveRef("merge1")
+// require.NoError(t, err)
+// require.NotEqual(t, merge1, refMerge1)
+// commitRefMerge1, err := repo.ReadCommit(refMerge1)
+// require.NoError(t, err)
+// require.ElementsMatch(t, commitRefMerge1.Parents, []Hash{merge1, merge2})
+// refMerge2, err = repo.ResolveRef("merge2")
+// require.NoError(t, err)
+// require.Equal(t, merge2, refMerge2)
diff --git a/entity/dag/operation.go b/entity/dag/operation.go
new file mode 100644
index 00000000..9fcc055b
--- /dev/null
+++ b/entity/dag/operation.go
@@ -0,0 +1,31 @@
+package dag
+
+import (
+ "github.com/MichaelMure/git-bug/entity"
+ "github.com/MichaelMure/git-bug/identity"
+)
+
+// Operation is a piece of data defining a change to reflect on the state of an Entity.
+// What this Operation or Entity's state looks like is not of the resort of this package as it only deals with the
+// data structure and storage.
+type Operation interface {
+ // Id return the Operation identifier
+ // Some care need to be taken to define a correct Id derivation and enough entropy in the data used to avoid
+ // collisions. Notably:
+ // - the Id of the first Operation will be used as the Id of the Entity. Collision need to be avoided across Entities.
+ // - collisions can also happen within the set of Operations of an Entity. Simple Operation might not have enough
+ // entropy to yield unique Ids.
+ // A common way to derive an Id will be to use the DeriveId function on the serialized operation data.
+ Id() entity.Id
+ // Validate check if the Operation data is valid
+ Validate() error
+
+ Author() identity.Interface
+}
+
+type operationBase struct {
+ author identity.Interface
+
+ // Not serialized. Store the op's id in memory.
+ id entity.Id
+}
diff --git a/entity/dag/operation_pack.go b/entity/dag/operation_pack.go
new file mode 100644
index 00000000..7cf4ee58
--- /dev/null
+++ b/entity/dag/operation_pack.go
@@ -0,0 +1,294 @@
+package dag
+
+import (
+ "encoding/json"
+ "fmt"
+ "strconv"
+ "strings"
+
+ "github.com/pkg/errors"
+ "golang.org/x/crypto/openpgp"
+
+ "github.com/MichaelMure/git-bug/entity"
+ "github.com/MichaelMure/git-bug/identity"
+ "github.com/MichaelMure/git-bug/repository"
+ "github.com/MichaelMure/git-bug/util/lamport"
+)
+
+// TODO: extra data tree
+const extraEntryName = "extra"
+
+const opsEntryName = "ops"
+const versionEntryPrefix = "version-"
+const createClockEntryPrefix = "create-clock-"
+const editClockEntryPrefix = "edit-clock-"
+const packClockEntryPrefix = "pack-clock-"
+
+// operationPack is a wrapper structure to store multiple operations in a single git blob.
+// Additionally, it holds and store the metadata for those operations.
+type operationPack struct {
+ // An identifier, taken from a hash of the serialized Operations.
+ id entity.Id
+
+ // The author of the Operations. Must be the same author for all the Operations.
+ Author identity.Interface
+ // The list of Operation stored in the operationPack
+ Operations []Operation
+ // Encode the entity's logical time of creation across all entities of the same type.
+ // Only exist on the root operationPack
+ CreateTime lamport.Time
+ // Encode the entity's logical time of last edition across all entities of the same type.
+ // Exist on all operationPack
+ EditTime lamport.Time
+ // // Encode the operationPack's logical time of creation withing this entity.
+ // // Exist on all operationPack
+ // PackTime lamport.Time
+}
+
+func (opp *operationPack) Id() entity.Id {
+ if opp.id == "" || opp.id == entity.UnsetId {
+ // This means we are trying to get the opp's Id *before* it has been stored.
+ // As the Id is computed based on the actual bytes written on the disk, we are going to predict
+ // those and then get the Id. This is safe as it will be the exact same code writing on disk later.
+
+ data, err := json.Marshal(opp)
+ if err != nil {
+ panic(err)
+ }
+ opp.id = entity.DeriveId(data)
+ }
+
+ return opp.id
+}
+
+func (opp *operationPack) MarshalJSON() ([]byte, error) {
+ return json.Marshal(struct {
+ Author identity.Interface `json:"author"`
+ Operations []Operation `json:"ops"`
+ }{
+ Author: opp.Author,
+ Operations: opp.Operations,
+ })
+}
+
+func (opp *operationPack) Validate() error {
+ if opp.Author == nil {
+ return fmt.Errorf("missing author")
+ }
+ for _, op := range opp.Operations {
+ if op.Author() != opp.Author {
+ return fmt.Errorf("operation has different author than the operationPack's")
+ }
+ }
+ if opp.EditTime == 0 {
+ return fmt.Errorf("lamport edit time is zero")
+ }
+ return nil
+}
+
+func (opp *operationPack) Write(def Definition, repo repository.RepoData, parentCommit ...repository.Hash) (repository.Hash, error) {
+ if err := opp.Validate(); err != nil {
+ return "", err
+ }
+
+ // For different reason, we store the clocks and format version directly in the git tree.
+ // Version has to be accessible before any attempt to decode to return early with a unique error.
+ // Clocks could possibly be stored in the git blob but it's nice to separate data and metadata, and
+ // we are storing something directly in the tree already so why not.
+ //
+ // To have a valid Tree, we point the "fake" entries to always the same value, the empty blob.
+ emptyBlobHash, err := repo.StoreData([]byte{})
+ if err != nil {
+ return "", err
+ }
+
+ // Write the Ops as a Git blob containing the serialized array of operations
+ data, err := json.Marshal(opp)
+ if err != nil {
+ return "", err
+ }
+
+ // compute the Id while we have the serialized data
+ opp.id = entity.DeriveId(data)
+
+ hash, err := repo.StoreData(data)
+ if err != nil {
+ return "", err
+ }
+
+ // Make a Git tree referencing this blob and encoding the other values:
+ // - format version
+ // - clocks
+ tree := []repository.TreeEntry{
+ {ObjectType: repository.Blob, Hash: emptyBlobHash,
+ Name: fmt.Sprintf(versionEntryPrefix+"%d", def.formatVersion)},
+ {ObjectType: repository.Blob, Hash: hash,
+ Name: opsEntryName},
+ {ObjectType: repository.Blob, Hash: emptyBlobHash,
+ Name: fmt.Sprintf(editClockEntryPrefix+"%d", opp.EditTime)},
+ // {ObjectType: repository.Blob, Hash: emptyBlobHash,
+ // Name: fmt.Sprintf(packClockEntryPrefix+"%d", opp.PackTime)},
+ }
+ if opp.CreateTime > 0 {
+ tree = append(tree, repository.TreeEntry{
+ ObjectType: repository.Blob,
+ Hash: emptyBlobHash,
+ Name: fmt.Sprintf(createClockEntryPrefix+"%d", opp.CreateTime),
+ })
+ }
+
+ // Store the tree
+ treeHash, err := repo.StoreTree(tree)
+ if err != nil {
+ return "", err
+ }
+
+ // Write a Git commit referencing the tree, with the previous commit as parent
+ // If we have keys, sign.
+ var commitHash repository.Hash
+
+ // Sign the commit if we have a key
+ if opp.Author.SigningKey() != nil {
+ commitHash, err = repo.StoreSignedCommit(treeHash, opp.Author.SigningKey().PGPEntity(), parentCommit...)
+ } else {
+ commitHash, err = repo.StoreCommit(treeHash, parentCommit...)
+ }
+
+ if err != nil {
+ return "", err
+ }
+
+ return commitHash, nil
+}
+
+// readOperationPack read the operationPack encoded in git at the given Tree hash.
+//
+// Validity of the Lamport clocks is left for the caller to decide.
+func readOperationPack(def Definition, repo repository.RepoData, commit repository.Commit) (*operationPack, error) {
+ entries, err := repo.ReadTree(commit.TreeHash)
+ if err != nil {
+ return nil, err
+ }
+
+ // check the format version first, fail early instead of trying to read something
+ var version uint
+ for _, entry := range entries {
+ if strings.HasPrefix(entry.Name, versionEntryPrefix) {
+ v, err := strconv.ParseUint(strings.TrimPrefix(entry.Name, versionEntryPrefix), 10, 64)
+ if err != nil {
+ return nil, errors.Wrap(err, "can't read format version")
+ }
+ if v > 1<<12 {
+ return nil, fmt.Errorf("format version too big")
+ }
+ version = uint(v)
+ break
+ }
+ }
+ if version == 0 {
+ return nil, entity.NewErrUnknowFormat(def.formatVersion)
+ }
+ if version != def.formatVersion {
+ return nil, entity.NewErrInvalidFormat(version, def.formatVersion)
+ }
+
+ var id entity.Id
+ var author identity.Interface
+ var ops []Operation
+ var createTime lamport.Time
+ var editTime lamport.Time
+ // var packTime lamport.Time
+
+ for _, entry := range entries {
+ switch {
+ case entry.Name == opsEntryName:
+ data, err := repo.ReadData(entry.Hash)
+ if err != nil {
+ return nil, errors.Wrap(err, "failed to read git blob data")
+ }
+ ops, author, err = unmarshallPack(def, data)
+ if err != nil {
+ return nil, err
+ }
+ id = entity.DeriveId(data)
+
+ case strings.HasPrefix(entry.Name, createClockEntryPrefix):
+ v, err := strconv.ParseUint(strings.TrimPrefix(entry.Name, createClockEntryPrefix), 10, 64)
+ if err != nil {
+ return nil, errors.Wrap(err, "can't read creation lamport time")
+ }
+ createTime = lamport.Time(v)
+
+ case strings.HasPrefix(entry.Name, editClockEntryPrefix):
+ v, err := strconv.ParseUint(strings.TrimPrefix(entry.Name, editClockEntryPrefix), 10, 64)
+ if err != nil {
+ return nil, errors.Wrap(err, "can't read edit lamport time")
+ }
+ editTime = lamport.Time(v)
+
+ // case strings.HasPrefix(entry.Name, packClockEntryPrefix):
+ // found &= 1 << 3
+ //
+ // v, err := strconv.ParseUint(strings.TrimPrefix(entry.Name, packClockEntryPrefix), 10, 64)
+ // if err != nil {
+ // return nil, errors.Wrap(err, "can't read pack lamport time")
+ // }
+ // packTime = lamport.Time(v)
+ }
+ }
+
+ // Verify signature if we expect one
+ keys := author.ValidKeysAtTime(fmt.Sprintf(editClockPattern, def.namespace), editTime)
+ if len(keys) > 0 {
+ keyring := identity.PGPKeyring(keys)
+ _, err = openpgp.CheckDetachedSignature(keyring, commit.SignedData, commit.Signature)
+ if err != nil {
+ return nil, fmt.Errorf("signature failure: %v", err)
+ }
+ }
+
+ return &operationPack{
+ id: id,
+ Author: author,
+ Operations: ops,
+ CreateTime: createTime,
+ EditTime: editTime,
+ // PackTime: packTime,
+ }, nil
+}
+
+// unmarshallPack delegate the unmarshalling of the Operation's JSON to the decoding
+// function provided by the concrete entity. This gives access to the concrete type of each
+// Operation.
+func unmarshallPack(def Definition, data []byte) ([]Operation, identity.Interface, error) {
+ aux := struct {
+ Author identity.IdentityStub `json:"author"`
+ Operations []json.RawMessage `json:"ops"`
+ }{}
+
+ if err := json.Unmarshal(data, &aux); err != nil {
+ return nil, nil, err
+ }
+
+ if aux.Author.Id() == "" || aux.Author.Id() == entity.UnsetId {
+ return nil, nil, fmt.Errorf("missing author")
+ }
+
+ author, err := def.identityResolver.ResolveIdentity(aux.Author.Id())
+ if err != nil {
+ return nil, nil, err
+ }
+
+ ops := make([]Operation, 0, len(aux.Operations))
+
+ for _, raw := range aux.Operations {
+ // delegate to specialized unmarshal function
+ op, err := def.operationUnmarshaler(author, raw)
+ if err != nil {
+ return nil, nil, err
+ }
+ ops = append(ops, op)
+ }
+
+ return ops, author, nil
+}
diff --git a/entity/dag/operation_pack_test.go b/entity/dag/operation_pack_test.go
new file mode 100644
index 00000000..ad2a9859
--- /dev/null
+++ b/entity/dag/operation_pack_test.go
@@ -0,0 +1,44 @@
+package dag
+
+import (
+ "testing"
+
+ "github.com/stretchr/testify/require"
+)
+
+func TestOperationPackReadWrite(t *testing.T) {
+ repo, id1, _, def := makeTestContext()
+
+ opp := &operationPack{
+ Author: id1,
+ Operations: []Operation{
+ newOp1(id1, "foo"),
+ newOp2(id1, "bar"),
+ },
+ CreateTime: 123,
+ EditTime: 456,
+ }
+
+ commitHash, err := opp.Write(def, repo)
+ require.NoError(t, err)
+
+ commit, err := repo.ReadCommit(commitHash)
+ require.NoError(t, err)
+
+ opp2, err := readOperationPack(def, repo, commit)
+ require.NoError(t, err)
+
+ require.Equal(t, opp, opp2)
+
+ // make sure we get the same Id with the same data
+ opp3 := &operationPack{
+ Author: id1,
+ Operations: []Operation{
+ newOp1(id1, "foo"),
+ newOp2(id1, "bar"),
+ },
+ CreateTime: 123,
+ EditTime: 456,
+ }
+ require.Equal(t, opp.Id(), opp3.Id())
+}
generated by cgit (git 2.34.1) at 2024-11-10 04:57:43 +0000