1 files changed, 111 insertions, 0 deletions
diff --git a/cache/cached.go b/cache/cached.go
new file mode 100644
index 00000000..9f9e170d
--- /dev/null
+++ b/cache/cached.go
@@ -0,0 +1,111 @@
+package cache
+
+import (
+	"sync"
+
+	"github.com/MichaelMure/git-bug/entity"
+	"github.com/MichaelMure/git-bug/entity/dag"
+	"github.com/MichaelMure/git-bug/repository"
+	"github.com/MichaelMure/git-bug/util/lamport"
+)
+
+var _ CacheEntity = &CachedEntityBase[dag.Snapshot, dag.Operation]{}
+
+// CachedEntityBase provide the base function of an entity managed by the cache.
+type CachedEntityBase[SnapT dag.Snapshot, OpT dag.Operation] struct {
+	repo            repository.ClockedRepo
+	entityUpdated   func(id entity.Id) error
+	getUserIdentity getUserIdentityFunc
+
+	mu     sync.RWMutex
+	entity dag.Interface[SnapT, OpT]
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) Id() entity.Id {
+	return e.entity.Id()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) Snapshot() SnapT {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.entity.Compile()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) notifyUpdated() error {
+	return e.entityUpdated(e.entity.Id())
+}
+
+// ResolveOperationWithMetadata will find an operation that has the matching metadata
+func (e *CachedEntityBase[SnapT, OpT]) ResolveOperationWithMetadata(key string, value string) (entity.Id, error) {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	// preallocate but empty
+	matching := make([]entity.Id, 0, 5)
+
+	for _, op := range e.entity.Operations() {
+		opValue, ok := op.GetMetadata(key)
+		if ok && value == opValue {
+			matching = append(matching, op.Id())
+		}
+	}
+
+	if len(matching) == 0 {
+		return "", ErrNoMatchingOp
+	}
+
+	if len(matching) > 1 {
+		return "", entity.NewErrMultipleMatch("operation", matching)
+	}
+
+	return matching[0], nil
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) Validate() error {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.entity.Validate()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) Commit() error {
+	e.mu.Lock()
+	err := e.entity.Commit(e.repo)
+	if err != nil {
+		e.mu.Unlock()
+		return err
+	}
+	e.mu.Unlock()
+	return e.notifyUpdated()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) CommitAsNeeded() error {
+	e.mu.Lock()
+	err := e.entity.CommitAsNeeded(e.repo)
+	if err != nil {
+		e.mu.Unlock()
+		return err
+	}
+	e.mu.Unlock()
+	return e.notifyUpdated()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) NeedCommit() bool {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.entity.NeedCommit()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) Lock() {
+	e.mu.Lock()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) CreateLamportTime() lamport.Time {
+	return e.entity.CreateLamportTime()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) EditLamportTime() lamport.Time {
+	return e.entity.EditLamportTime()
+}
+
+func (e *CachedEntityBase[SnapT, OpT]) FirstOp() OpT {
+	return e.entity.FirstOp()
+}