Merge pull request #844 from MichaelMure/resolvers

WIP resolvers

1 files changed, 81 insertions, 9 deletions

diff --git a/entity/dag/entity.go b/entity/dag/entity.go
index 4ccf0e0e..09f37246 100644
--- a/entity/dag/entity.go
+++ b/entity/dag/entity.go
@@ -26,7 +26,7 @@ type Definition struct {
 	// the Namespace in git references (bugs, prs, ...)
 	Namespace string
 	// a function decoding a JSON message into an Operation
-	OperationUnmarshaler func(raw json.RawMessage, resolver identity.Resolver) (Operation, error)
+	OperationUnmarshaler func(raw json.RawMessage, resolver entity.Resolvers) (Operation, error)
 	// the expected format version number, that can be used for data migration/upgrade
 	FormatVersion uint
 }
@@ -57,29 +57,29 @@ func New(definition Definition) *Entity {
 }
 
 // Read will read and decode a stored local Entity from a repository
-func Read(def Definition, repo repository.ClockedRepo, resolver identity.Resolver, id entity.Id) (*Entity, error) {
+func Read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, 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, resolver, ref)
+	return read(def, repo, resolvers, ref)
 }
 
 // readRemote will read and decode a stored remote Entity from a repository
-func readRemote(def Definition, repo repository.ClockedRepo, resolver identity.Resolver, remote string, id entity.Id) (*Entity, error) {
+func readRemote(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, remote string, id entity.Id) (*Entity, error) {
 	if err := id.Validate(); err != nil {
 		return nil, errors.Wrap(err, "invalid id")
 	}
 
 	ref := fmt.Sprintf("refs/remotes/%s/%s/%s", def.Namespace, remote, id.String())
 
-	return read(def, repo, resolver, ref)
+	return read(def, repo, resolvers, ref)
 }
 
 // read fetch from git and decode an Entity at an arbitrary git reference.
-func read(def Definition, repo repository.ClockedRepo, resolver identity.Resolver, ref string) (*Entity, error) {
+func read(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers, ref string) (*Entity, error) {
 	rootHash, err := repo.ResolveRef(ref)
 	if err != nil {
 		return nil, err
@@ -138,7 +138,7 @@ func read(def Definition, repo repository.ClockedRepo, resolver identity.Resolve
 			return nil, fmt.Errorf("multiple leafs in the entity DAG")
 		}
 
-		opp, err := readOperationPack(def, repo, resolver, commit)
+		opp, err := readOperationPack(def, repo, resolvers, commit)
 		if err != nil {
 			return nil, err
 		}
@@ -239,13 +239,65 @@ func read(def Definition, repo repository.ClockedRepo, resolver identity.Resolve
 	}, nil
 }
 
+// readClockNoCheck fetch from git, read and witness the clocks of an Entity at an arbitrary git reference.
+// Note: readClockNoCheck does not verify the integrity of the Entity and could witness incorrect or incomplete
+// clocks if so. If data integrity check is a requirement, a flow similar to read without actually reading/decoding
+// operation blobs can be implemented instead.
+func readClockNoCheck(def Definition, repo repository.ClockedRepo, ref string) error {
+	rootHash, err := repo.ResolveRef(ref)
+	if err != nil {
+		return err
+	}
+
+	commit, err := repo.ReadCommit(rootHash)
+	if err != nil {
+		return err
+	}
+
+	createTime, editTime, err := readOperationPackClock(repo, commit)
+	if err != nil {
+		return err
+	}
+
+	// if we have more than one commit, we need to find the root to have the create time
+	if len(commit.Parents) > 0 {
+		for len(commit.Parents) > 0 {
+			// The path to the root is irrelevant.
+			commit, err = repo.ReadCommit(commit.Parents[0])
+			if err != nil {
+				return err
+			}
+		}
+		createTime, _, err = readOperationPackClock(repo, commit)
+		if err != nil {
+			return err
+		}
+	}
+
+	if createTime <= 0 {
+		return fmt.Errorf("creation lamport time not set")
+	}
+	if editTime <= 0 {
+		return fmt.Errorf("creation lamport time not set")
+	}
+	err = repo.Witness(fmt.Sprintf(creationClockPattern, def.Namespace), createTime)
+	if err != nil {
+		return err
+	}
+	err = repo.Witness(fmt.Sprintf(editClockPattern, def.Namespace), editTime)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 type StreamedEntity struct {
 	Entity *Entity
 	Err    error
 }
 
 // ReadAll read and parse all local Entity
-func ReadAll(def Definition, repo repository.ClockedRepo, resolver identity.Resolver) <-chan StreamedEntity {
+func ReadAll(def Definition, repo repository.ClockedRepo, resolvers entity.Resolvers) <-chan StreamedEntity {
 	out := make(chan StreamedEntity)
 
 	go func() {
@@ -260,7 +312,7 @@ func ReadAll(def Definition, repo repository.ClockedRepo, resolver identity.Reso
 		}
 
 		for _, ref := range refs {
-			e, err := read(def, repo, resolver, ref)
+			e, err := read(def, repo, resolvers, ref)
 
 			if err != nil {
 				out <- StreamedEntity{Err: err}
@@ -274,6 +326,26 @@ func ReadAll(def Definition, repo repository.ClockedRepo, resolver identity.Reso
 	return out
 }
 
+// ReadAllClocksNoCheck goes over all entities matching Definition and read/witness the corresponding clocks so that the
+// repo end up with correct clocks for the next write.
+func ReadAllClocksNoCheck(def Definition, repo repository.ClockedRepo) error {
+	refPrefix := fmt.Sprintf("refs/%s/", def.Namespace)
+
+	refs, err := repo.ListRefs(refPrefix)
+	if err != nil {
+		return err
+	}
+
+	for _, ref := range refs {
+		err = readClockNoCheck(def, repo, ref)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // Id return the Entity identifier
 func (e *Entity) Id() entity.Id {
 	// id is the id of the first operation