From cc7617a302d22e6041d397c3cb033e0c6b9f13e8 Mon Sep 17 00:00:00 2001
From: Greyson Parrelli <greyson@signal.org>
Date: Mon, 22 Feb 2021 11:47:57 -0500
Subject: [PATCH] Throttle conversation list update frequency.

Reduces the load on the database (and UI jankiness) while processing a
large message backlog.
---
 .../ConversationListViewModel.java            | 22 ++++++++++++-------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/app/src/main/java/org/thoughtcrime/securesms/conversationlist/ConversationListViewModel.java b/app/src/main/java/org/thoughtcrime/securesms/conversationlist/ConversationListViewModel.java
index 234133ff7..71f7628ab 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/conversationlist/ConversationListViewModel.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/conversationlist/ConversationListViewModel.java
@@ -24,6 +24,7 @@ import org.thoughtcrime.securesms.megaphone.Megaphones;
 import org.thoughtcrime.securesms.net.PipeConnectivityListener;
 import org.thoughtcrime.securesms.search.SearchRepository;
 import org.thoughtcrime.securesms.util.Debouncer;
+import org.thoughtcrime.securesms.util.ThrottledDebouncer;
 import org.thoughtcrime.securesms.util.Util;
 import org.thoughtcrime.securesms.util.livedata.LiveDataUtil;
 import org.thoughtcrime.securesms.util.paging.Invalidator;
@@ -42,7 +43,8 @@ class ConversationListViewModel extends ViewModel {
   private final LiveData<Boolean>              hasNoConversations;
   private final SearchRepository               searchRepository;
   private final MegaphoneRepository            megaphoneRepository;
-  private final Debouncer                      debouncer;
+  private final Debouncer                      searchDebouncer;
+  private final ThrottledDebouncer             updateDebouncer;
   private final DatabaseObserver.Observer      observer;
   private final Invalidator                    invalidator;
 
@@ -54,7 +56,8 @@ class ConversationListViewModel extends ViewModel {
     this.searchResult        = new MutableLiveData<>();
     this.searchRepository    = searchRepository;
     this.megaphoneRepository = ApplicationDependencies.getMegaphoneRepository();
-    this.debouncer           = new Debouncer(300);
+    this.searchDebouncer     = new Debouncer(300);
+    this.updateDebouncer     = new ThrottledDebouncer(500);
     this.invalidator         = new Invalidator();
     this.pagedData           = PagedData.create(ConversationListDataSource.create(application, isArchived),
                                                 new PagingConfig.Builder()
@@ -62,10 +65,12 @@ class ConversationListViewModel extends ViewModel {
                                                                 .setBufferPages(2)
                                                                 .build());
     this.observer            = () -> {
-      if (!TextUtils.isEmpty(getLastQuery())) {
-        searchRepository.query(getLastQuery(), searchResult::postValue);
-      }
-      pagedData.getController().onDataInvalidated();
+      updateDebouncer.publish(() -> {
+        if (!TextUtils.isEmpty(getLastQuery())) {
+          searchRepository.query(getLastQuery(), searchResult::postValue);
+        }
+        pagedData.getController().onDataInvalidated();
+      });
     };
 
     this.hasNoConversations = LiveDataUtil.mapAsync(pagedData.getData(), conversations -> {
@@ -135,7 +140,7 @@ class ConversationListViewModel extends ViewModel {
 
   void updateQuery(String query) {
     lastQuery = query;
-    debouncer.publish(() -> searchRepository.query(query, result -> {
+    searchDebouncer.publish(() -> searchRepository.query(query, result -> {
       Util.runOnMain(() -> {
         if (query.equals(lastQuery)) {
           searchResult.setValue(result);
@@ -151,7 +156,8 @@ class ConversationListViewModel extends ViewModel {
   @Override
   protected void onCleared() {
     invalidator.invalidate();
-    debouncer.clear();
+    searchDebouncer.clear();
+    updateDebouncer.clear();
     ApplicationDependencies.getDatabaseObserver().unregisterObserver(observer);
   }