Clean up methods related to presence (yorkie-team#594)

* Return presence to user by retrieving only online clients and making a copy

* Trigger unwatched event instead of presence-changed event during detach

api/converter/to_bytes.go

@@ -29,7 +29,7 @@ import (
 )
 
 // SnapshotToBytes converts the given document to byte array.
-func SnapshotToBytes(obj *crdt.Object, presences *innerpresence.Map) ([]byte, error) {
+func SnapshotToBytes(obj *crdt.Object, presences map[string]innerpresence.Presence) ([]byte, error) {
 	pbElem, err := toJSONElement(obj)
 	if err != nil {
 		return nil, err

api/converter/to_pb.go

@@ -122,12 +122,11 @@ func ToDocumentSummary(summary *types.DocumentSummary) (*api.DocumentSummary, er
 }
 
 // ToPresences converts the given model to Protobuf format.
-func ToPresences(presences *innerpresence.Map) map[string]*api.Presence {
+func ToPresences(presences map[string]innerpresence.Presence) map[string]*api.Presence {
 	pbPresences := make(map[string]*api.Presence)
-	presences.Range(func(k string, v innerpresence.Presence) bool {
+	for k, v := range presences {
 		pbPresences[k] = ToPresence(v)
-		return true
-	})
+	}
 	return pbPresences
 }
 

client/client.go

@@ -432,7 +432,7 @@ func (c *Client) Watch(
 				clientIDs = append(clientIDs, id.String())
 			}
 
-			doc.SetOnlineClientSet(clientIDs...)
+			doc.SetOnlineClients(clientIDs...)
 			return nil, nil
 		case *api.WatchDocumentResponse_Event:
 			eventType, err := converter.FromEventType(resp.Event.Type)
@@ -450,19 +450,22 @@ func (c *Client) Watch(
 				return &WatchResponse{Type: DocumentChanged}, nil
 			case types.DocumentsWatchedEvent:
 				doc.AddOnlineClient(cli.String())
-				if doc.OnlinePresence(cli.String()) == nil {
+				if doc.Presence(cli.String()) == nil {
 					return nil, nil
 				}
 
 				return &WatchResponse{
 					Type: DocumentWatched,
 					Presences: map[string]innerpresence.Presence{
-						cli.String(): doc.OnlinePresence(cli.String()),
+						cli.String(): doc.Presence(cli.String()),
 					},
 				}, nil
 			case types.DocumentsUnwatchedEvent:
-				p := doc.OnlinePresence(cli.String())
+				p := doc.Presence(cli.String())
 				doc.RemoveOnlineClient(cli.String())
+				if p == nil {
+					return nil, nil
+				}
 
 				return &WatchResponse{
 					Type: DocumentUnwatched,
@@ -521,6 +524,8 @@ func (c *Client) Watch(
 				t := PresenceChanged
 				if e.Type == document.WatchedEvent {
 					t = DocumentWatched
+				} else if e.Type == document.UnwatchedEvent {
+					t = DocumentUnwatched
 				}
 				rch <- WatchResponse{Type: t, Presences: e.Presences}
 			case <-ctx.Done():

pkg/document/document.go

@@ -43,6 +43,10 @@ const (
 	// enabling real-time synchronization.
 	WatchedEvent DocEventType = "watched"
 
+	// UnwatchedEvent means that the client has disconnected from the server,
+	// disabling real-time synchronization.
+	UnwatchedEvent DocEventType = "unwatched"
+
 	// PresenceChangedEvent means that the presences of the clients who are editing
 	// the document have changed.
 	PresenceChangedEvent DocEventType = "presence-changed"
@@ -282,48 +286,50 @@ func (d *Document) ensureClone() error {
 	return nil
 }
 
-// Presences returns the presence map of this document.
-func (d *Document) Presences() map[string]innerpresence.Presence {
-	// TODO(hackerwins): We need to use client key instead of actor ID for exposing presence.
-	presences := make(map[string]innerpresence.Presence)
-	d.doc.presences.Range(func(key string, value innerpresence.Presence) bool {
-		presences[key] = value
-		return true
-	})
-	return presences
+// MyPresence returns the presence of the actor.
+func (d *Document) MyPresence() innerpresence.Presence {
+	return d.doc.MyPresence()
 }
 
 // Presence returns the presence of the given client.
+// If the client is not online, it returns nil.
 func (d *Document) Presence(clientID string) innerpresence.Presence {
 	return d.doc.Presence(clientID)
 }
 
-// MyPresence returns the presence of the actor.
-func (d *Document) MyPresence() innerpresence.Presence {
-	return d.doc.MyPresence()
+// PresenceForTest returns the presence of the given client
+// regardless of whether the client is online or not.
+func (d *Document) PresenceForTest(clientID string) innerpresence.Presence {
+	return d.doc.PresenceForTest(clientID)
 }
 
-// SetOnlineClientSet sets the online client set.
-func (d *Document) SetOnlineClientSet(clientIDs ...string) {
-	d.doc.SetOnlineClientSet(clientIDs...)
+// Presences returns the presence map of online clients.
+func (d *Document) Presences() map[string]innerpresence.Presence {
+	// TODO(hackerwins): We need to use client key instead of actor ID for exposing presence.
+	return d.doc.Presences()
+}
+
+// AllPresences returns the presence map of all clients
+// regardless of whether the client is online or not.
+func (d *Document) AllPresences() map[string]innerpresence.Presence {
+	return d.doc.AllPresences()
 }
 
-// AddOnlineClient adds the given client to the online client set.
+// SetOnlineClients sets the online clients.
+func (d *Document) SetOnlineClients(clientIDs ...string) {
+	d.doc.SetOnlineClients(clientIDs...)
+}
+
+// AddOnlineClient adds the given client to the online clients.
 func (d *Document) AddOnlineClient(clientID string) {
 	d.doc.AddOnlineClient(clientID)
 }
 
-// RemoveOnlineClient removes the given client from the online client set.
+// RemoveOnlineClient removes the given client from the online clients.
 func (d *Document) RemoveOnlineClient(clientID string) {
 	d.doc.RemoveOnlineClient(clientID)
 }
 
-// OnlinePresence returns the presence of the given client. If the client is not
-// online, it returns nil.
-func (d *Document) OnlinePresence(clientID string) innerpresence.Presence {
-	return d.doc.OnlinePresence(clientID)
-}
-
 // Events returns the events of this document.
 func (d *Document) Events() <-chan DocEvent {
 	return d.events

pkg/document/innerpresence/presence.go

@@ -50,13 +50,13 @@ func (m *Map) Range(f func(clientID string, presence Presence) bool) {
 }
 
 // Load returns the presence for the given clientID.
-func (m *Map) Load(clientID string) (Presence, bool) {
+func (m *Map) Load(clientID string) Presence {
 	presence, ok := m.presences.Load(clientID)
 	if !ok {
-		return nil, false
+		return nil
 	}
 
-	return presence.(Presence), true
+	return presence.(Presence)
 }
 
 // LoadOrStore returns the existing presence if exists.
@@ -140,6 +140,9 @@ func (p Presence) Clear() {
 
 // DeepCopy copies itself deeply.
 func (p Presence) DeepCopy() Presence {
+	if p == nil {
+		return nil
+	}
 	clone := make(map[string]string)
 	for k, v := range p {
 		clone[k] = v

pkg/document/internal_document.go

@@ -257,17 +257,29 @@ func (d *InternalDocument) ApplyChanges(changes ...*change.Change) ([]DocEvent,
 		if c.PresenceChange() != nil {
 			clientID := c.ID().ActorID().String()
 			if _, ok := d.onlineClients.Load(clientID); ok {
-				event := DocEvent{
-					Type: PresenceChangedEvent,
-					Presences: map[string]innerpresence.Presence{
-						clientID: c.PresenceChange().Presence,
-					},
+				switch c.PresenceChange().ChangeType {
+				case innerpresence.Put:
+					eventType := PresenceChangedEvent
+					if !d.presences.Has(clientID) {
+						eventType = WatchedEvent
+					}
+					event := DocEvent{
+						Type: eventType,
+						Presences: map[string]innerpresence.Presence{
+							clientID: c.PresenceChange().Presence,
+						},
+					}
+					events = append(events, event)
+				case innerpresence.Clear:
+					event := DocEvent{
+						Type: UnwatchedEvent,
+						Presences: map[string]innerpresence.Presence{
+							clientID: d.Presence(clientID),
+						},
+					}
+					events = append(events, event)
+					d.RemoveOnlineClient(clientID)
 				}
-
-				if !d.presences.Has(clientID) {
-					event.Type = WatchedEvent
-				}
-				events = append(events, event)
 			}
 		}
 
@@ -283,34 +295,56 @@ func (d *InternalDocument) ApplyChanges(changes ...*change.Change) ([]DocEvent,
 
 // MyPresence returns the presence of the actor currently editing the document.
 func (d *InternalDocument) MyPresence() innerpresence.Presence {
-	p := d.presences.LoadOrStore(d.changeID.ActorID().String(), innerpresence.NewPresence())
+	if d.status != StatusAttached {
+		return innerpresence.NewPresence()
+	}
+	p := d.presences.Load(d.changeID.ActorID().String())
 	return p.DeepCopy()
 }
 
-// Presences returns the map of presences of the actors currently editing the document.
-func (d *InternalDocument) Presences() *innerpresence.Map {
-	return d.presences
-}
-
-// OnlinePresence returns the presence of the given client. If the client is not
-// online, it returns nil.
-func (d *InternalDocument) OnlinePresence(clientID string) innerpresence.Presence {
+// Presence returns the presence of the given client.
+// If the client is not online, it returns nil.
+func (d *InternalDocument) Presence(clientID string) innerpresence.Presence {
 	if _, ok := d.onlineClients.Load(clientID); !ok {
 		return nil
 	}
 
-	presence, _ := d.presences.Load(clientID)
-	return presence
+	return d.presences.Load(clientID).DeepCopy()
 }
 
-// Presence returns the presence of the given client.
-func (d *InternalDocument) Presence(clientID string) innerpresence.Presence {
-	presence, _ := d.presences.Load(clientID)
-	return presence
+// PresenceForTest returns the presence of the given client
+// regardless of whether the client is online or not.
+func (d *InternalDocument) PresenceForTest(clientID string) innerpresence.Presence {
+	return d.presences.Load(clientID).DeepCopy()
+}
+
+// Presences returns the presence map of online clients.
+func (d *InternalDocument) Presences() map[string]innerpresence.Presence {
+	presences := make(map[string]innerpresence.Presence)
+	d.onlineClients.Range(func(key, value interface{}) bool {
+		p := d.presences.Load(key.(string))
+		if p == nil {
+			return true
+		}
+		presences[key.(string)] = p.DeepCopy()
+		return true
+	})
+	return presences
+}
+
+// AllPresences returns the presence map of all clients
+// regardless of whether the client is online or not.
+func (d *InternalDocument) AllPresences() map[string]innerpresence.Presence {
+	presences := make(map[string]innerpresence.Presence)
+	d.presences.Range(func(key string, value innerpresence.Presence) bool {
+		presences[key] = value.DeepCopy()
+		return true
+	})
+	return presences
 }
 
-// SetOnlineClientSet sets the online client set.
-func (d *InternalDocument) SetOnlineClientSet(ids ...string) {
+// SetOnlineClients sets the online clients.
+func (d *InternalDocument) SetOnlineClients(ids ...string) {
 	d.onlineClients.Range(func(key, value interface{}) bool {
 		d.onlineClients.Delete(key)
 		return true
@@ -321,12 +355,12 @@ func (d *InternalDocument) SetOnlineClientSet(ids ...string) {
 	}
 }
 
-// AddOnlineClient adds the given client to the online client set.
+// AddOnlineClient adds the given client to the online clients.
 func (d *InternalDocument) AddOnlineClient(clientID string) {
 	d.onlineClients.Store(clientID, true)
 }
 
-// RemoveOnlineClient removes the given client from the online client set.
+// RemoveOnlineClient removes the given client from the online clients.
 func (d *InternalDocument) RemoveOnlineClient(clientID string) {
 	d.onlineClients.Delete(clientID)
 }

server/backend/database/memory/database.go

@@ -947,7 +947,7 @@ func (d *DB) CreateSnapshotInfo(
 	docID types.ID,
 	doc *document.InternalDocument,
 ) error {
-	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.Presences())
+	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.AllPresences())
 	if err != nil {
 		return err
 	}

server/backend/database/mongo/client.go

@@ -1031,7 +1031,7 @@ func (c *Client) CreateSnapshotInfo(
 	if err != nil {
 		return err
 	}
-	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.Presences())
+	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.AllPresences())
 	if err != nil {
 		return err
 	}

server/packs/pushpull.go

@@ -157,7 +157,7 @@ func pullSnapshot(
 	}
 	cpAfterPull := cpAfterPush.NextServerSeq(docInfo.ServerSeq)
 
-	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.Presences())
+	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.AllPresences())
 	if err != nil {
 		return nil, err
 	}

server/rpc/admin_server.go

@@ -254,7 +254,7 @@ func (s *adminServer) GetSnapshotMeta(
 		return nil, err
 	}
 
-	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.Presences())
+	snapshot, err := converter.SnapshotToBytes(doc.RootObject(), doc.AllPresences())
 	if err != nil {
 		return nil, err
 	}