[PERF] model: avoid useless finalize on initialization

Currently, finalize will be called after each replay of a
`stateUpdateMessage` during the Model instanciation. Depending on the
type of revisions and on the number of cells to evaluate, this can end
up having a devastating effect on the performance at first load.

2 examples:
- on a spreadsheet on 450*26 cells (all filled) with 300 random but
  simple revisions, we spend 2.8 seconds in the evaluaion
- A client spreadsheet in 16.0 with 1100 revisions cannot load due to a
  crash of the broweer tab

This revision adds a "loading state" where the finalize is disabled and
only used once after the replay of all stateUpdateMessages.

closes #4969

Task: 4176216
X-original-commit: 512617b
Signed-off-by: Lucas Lefèvre (lul) <[email protected]>
Signed-off-by: Rémi Rahir (rar) <[email protected]>

src/model.ts

@@ -114,6 +114,7 @@ export class Model extends EventBus<any> implements CommandDispatcher {
    */
   private renderers: [UIPlugin, LAYERS][] = [];
 
+  private isLoading: boolean;
   /**
    * Internal status of the model. Important for command handling coordination
    */
@@ -219,6 +220,11 @@ export class Model extends EventBus<any> implements CommandDispatcher {
     this.selection.observe(this, {
       handleEvent: () => this.trigger("update"),
     });
+
+    // move in "Loading" mode where we ignore redundant calls to finalize triggered by the
+    // replay of stateUpdateMessages in the session
+    this.isLoading = true;
+
     // This should be done after construction of LocalHistory due to order of
     // events
     this.setupSessionEvents();
@@ -233,6 +239,10 @@ export class Model extends EventBus<any> implements CommandDispatcher {
     // mark all models as "raw", so they will not be turned into reactive objects
     // by owl, since we do not rely on reactivity
     markRaw(this);
+
+    this.isLoading = false;
+    // ensure propre recomputation of plugin states after the message replays
+    this.finalize();
   }
 
   joinSession() {
@@ -368,6 +378,9 @@ export class Model extends EventBus<any> implements CommandDispatcher {
   }
 
   private finalize() {
+    if (this.isLoading) {
+      return;
+    }
     this.status = Status.Finalizing;
     for (const h of this.handlers) {
       h.finalize();