Add Event to MergeTree and Sequence on Local Segment Op Ack (#5045) (#5054)

Emit a new maintenance event, ACKNOWLEDGED when the op is round tripped from the server and the local segment is ack

Author: anthony-murphy

packages/dds/merge-tree/src/mergeTree.ts

@@ -1300,7 +1300,8 @@ export class MergeTree {
                                 this.mergeTreeMaintenanceCallback({
                                     operation: MergeTreeMaintenanceType.UNLINK,
                                     deltaSegments: [{ segment }],
-                                });
+                                },
+                                undefined);
                             }
 
                             segment.parent = undefined;
@@ -1325,7 +1326,8 @@ export class MergeTree {
                                     this.mergeTreeMaintenanceCallback({
                                         operation: MergeTreeMaintenanceType.APPEND,
                                         deltaSegments: [{ segment: prevSegment! }, { segment }],
-                                    });
+                                    },
+                                    undefined);
                                 }
                                 segment.parent = undefined;
                                 segment.trackingCollection.trackingGroups.forEach((tg) => tg.unlink(segment));
@@ -1881,6 +1883,8 @@ export class MergeTree {
             if (verboseOps) {
                 console.log(`segment group has ${pendingSegmentGroup.segments.length} segments`);
             }
+
+            const deltaSegments: IMergeTreeSegmentDelta[] = [];
             pendingSegmentGroup.segments.map((pendingSegment) => {
                 overwrite = !pendingSegment.ack(pendingSegmentGroup, opArgs, this) || overwrite;
                 if (MergeTree.options.zamboniSegments) {
@@ -1889,7 +1893,19 @@ export class MergeTree {
                 if (!nodesToUpdate.includes(pendingSegment.parent!)) {
                     nodesToUpdate.push(pendingSegment.parent!);
                 }
+                deltaSegments.push({
+                    segment:pendingSegment,
+                });
             });
+            if(this.mergeTreeMaintenanceCallback) {
+                this.mergeTreeMaintenanceCallback(
+                    {
+                        deltaSegments,
+                        operation: MergeTreeMaintenanceType.ACKNOWLEDGED,
+                    },
+                    opArgs,
+                );
+            }
             const clientId = this.collabWindow.clientId;
             for (const node of nodesToUpdate) {
                 this.blockUpdatePathLengths(node, seq, clientId, overwrite);
@@ -2227,7 +2243,8 @@ export class MergeTree {
             this.mergeTreeMaintenanceCallback({
                 operation: MergeTreeMaintenanceType.SPLIT,
                 deltaSegments: [{ segment }, { segment: next }],
-            });
+            },
+            undefined);
         }
 
         return { next };

packages/dds/merge-tree/src/mergeTreeDeltaCallback.ts

@@ -25,6 +25,11 @@ export const enum MergeTreeMaintenanceType {
      *    b) The segment's tracking collection is empty (e.g., not being tracked for undo/redo).
      */
     UNLINK  = -3,
+    /**
+     * Notification that a local change has been acknowledged by the server.
+     * This means that it has made the round trip to the server and has had a sequence number assigned.
+     */
+    ACKNOWLEDGED = -4,
 }
 
 export type MergeTreeDeltaOperationTypes = MergeTreeDeltaOperationType | MergeTreeMaintenanceType;
@@ -70,4 +75,4 @@ export type MergeTreeDeltaCallback =
 export interface IMergeTreeMaintenanceCallbackArgs extends IMergeTreeDeltaCallbackArgs<MergeTreeMaintenanceType> { }
 
 export type MergeTreeMaintenanceCallback =
-    (MaintenanceArgs: IMergeTreeMaintenanceCallbackArgs) => void;
+    (MaintenanceArgs: IMergeTreeMaintenanceCallbackArgs, opArgs: IMergeTreeDeltaOpArgs | undefined) => void;

packages/dds/merge-tree/src/test/mergeTree.markRangeRemoved.deltaCallback.spec.ts

@@ -88,6 +88,7 @@ describe("MergeTree", () => {
                 [MergeTreeDeltaType.REMOVE]: 1,
                 [MergeTreeMaintenanceType.SPLIT]: 2,
                 [MergeTreeMaintenanceType.UNLINK]: 1,
+                [MergeTreeMaintenanceType.ACKNOWLEDGED]: 1,
             });
         });
 

packages/dds/sequence/src/sequence.ts

@@ -144,8 +144,8 @@ export abstract class SharedSegmentSequence<T extends MergeTree.ISegment>
                     break;
                 case "maintenance":
                     if (!this.client.mergeTreeMaintenanceCallback) {
-                        this.client.mergeTreeMaintenanceCallback = (args) => {
-                            this.emit("maintenance", new SequenceMaintenanceEvent(args, this.client), this);
+                        this.client.mergeTreeMaintenanceCallback = (args, opArgs) => {
+                            this.emit("maintenance", new SequenceMaintenanceEvent(opArgs, args, this.client), this);
                         };
                     }
                     break;

packages/dds/sequence/src/sequenceDeltaEvent.ts

@@ -126,6 +126,7 @@ export class SequenceDeltaEvent extends SequenceEvent<MergeTreeDeltaOperationTyp
  */
 export class SequenceMaintenanceEvent extends SequenceEvent<MergeTreeMaintenanceType> {
     constructor(
+        public readonly opArgs: IMergeTreeDeltaOpArgs | undefined,
         deltaArgs: IMergeTreeMaintenanceCallbackArgs,
         mergeTreeClient: Client,
     ) {