Only notify for actual recipient changes.

app/src/main/java/org/thoughtcrime/securesms/recipients/LiveRecipient.java

@@ -18,6 +18,7 @@ import org.thoughtcrime.securesms.database.GroupDatabase.GroupRecord;
 import org.thoughtcrime.securesms.database.RecipientDatabase;
 import org.thoughtcrime.securesms.database.RecipientDatabase.RecipientSettings;
 import org.thoughtcrime.securesms.util.Util;
+import org.thoughtcrime.securesms.util.livedata.LiveDataUtil;
 import org.whispersystems.libsignal.util.guava.Optional;
 
 import java.util.List;
@@ -32,6 +33,7 @@ public final class LiveRecipient {
 
   private final Context                       context;
   private final MutableLiveData<Recipient>    liveData;
+  private final LiveData<Recipient>           observableLiveData;
   private final Set<RecipientForeverObserver> observers;
   private final Observer<Recipient>           foreverObserver;
   private final AtomicReference<Recipient>    recipient;
@@ -50,6 +52,7 @@ public final class LiveRecipient {
         o.onRecipientChanged(recipient);
       }
     };
+    this.observableLiveData = LiveDataUtil.distinctUntilChanged(liveData, Recipient::hasSameContent);
   }
 
   public @NonNull RecipientId getId() {
@@ -70,14 +73,14 @@ public final class LiveRecipient {
    * use {@link #removeObservers(LifecycleOwner)}.
    */
   public void observe(@NonNull LifecycleOwner owner, @NonNull Observer<Recipient> observer) {
-    Util.postToMain(() -> liveData.observe(owner, observer));
+    Util.postToMain(() -> observableLiveData.observe(owner, observer));
   }
 
   /**
    * Removes all observers of this data registered for the given LifecycleOwner.
    */
   public void removeObservers(@NonNull LifecycleOwner owner) {
-    Util.runOnMain(() -> liveData.removeObservers(owner));
+    Util.runOnMain(() -> observableLiveData.removeObservers(owner));
   }
 
   /**
@@ -88,7 +91,7 @@ public final class LiveRecipient {
   public void observeForever(@NonNull RecipientForeverObserver observer) {
     Util.postToMain(() -> {
       if (observers.isEmpty()) {
-        liveData.observeForever(foreverObserver);
+        observableLiveData.observeForever(foreverObserver);
       }
       observers.add(observer);
     });
@@ -102,7 +105,7 @@ public final class LiveRecipient {
       observers.remove(observer);
 
       if (observers.isEmpty()) {
-        liveData.removeObserver(foreverObserver);
+        observableLiveData.removeObserver(foreverObserver);
       }
     });
   }
@@ -172,7 +175,7 @@ public final class LiveRecipient {
   }
 
   public @NonNull LiveData<Recipient> getLiveData() {
-    return liveData;
+    return observableLiveData;
   }
 
   private @NonNull Recipient fetchAndCacheRecipientFromDisk(@NonNull RecipientId id) {

app/src/main/java/org/thoughtcrime/securesms/recipients/Recipient.java

@@ -47,6 +47,7 @@ import org.whispersystems.signalservice.api.push.SignalServiceAddress;
 import org.whispersystems.signalservice.api.util.UuidUtil;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedList;
@@ -873,6 +874,12 @@ public class Recipient {
     return id.equals(recipient.id);
   }
 
+  @Override
+  public int hashCode() {
+    return Objects.hash(id);
+  }
+
+
   public enum Capability {
     UNKNOWN(0),
     SUPPORTED(1),
@@ -902,11 +909,64 @@ public class Recipient {
     }
   }
 
-  @Override
-  public int hashCode() {
-    return Objects.hash(id);
+  public boolean hasSameContent(@NonNull Recipient other) {
+    return Objects.equals(id, other.id) &&
+           resolving == other.resolving &&
+           isSelf == other.isSelf &&
+           blocked == other.blocked &&
+           muteUntil == other.muteUntil &&
+           expireMessages == other.expireMessages &&
+           hasProfileImage == other.hasProfileImage &&
+           profileSharing == other.profileSharing &&
+           lastProfileFetch == other.lastProfileFetch &&
+           forceSmsSelection == other.forceSmsSelection &&
+           Objects.equals(id, other.id) &&
+           Objects.equals(uuid, other.uuid) &&
+           Objects.equals(username, other.username) &&
+           Objects.equals(e164, other.e164) &&
+           Objects.equals(email, other.email) &&
+           Objects.equals(groupId, other.groupId) &&
+           allContentsAreTheSame(participants, other.participants) &&
+           Objects.equals(groupAvatarId, other.groupAvatarId) &&
+           messageVibrate == other.messageVibrate &&
+           callVibrate == other.callVibrate &&
+           Objects.equals(messageRingtone, other.messageRingtone) &&
+           Objects.equals(callRingtone, other.callRingtone) &&
+           color == other.color &&
+           Objects.equals(defaultSubscriptionId, other.defaultSubscriptionId) &&
+           registered == other.registered &&
+           Arrays.equals(profileKey, other.profileKey) &&
+           Objects.equals(profileKeyCredential, other.profileKeyCredential) &&
+           Objects.equals(name, other.name) &&
+           Objects.equals(systemContactPhoto, other.systemContactPhoto) &&
+           Objects.equals(customLabel, other.customLabel) &&
+           Objects.equals(contactUri, other.contactUri) &&
+           Objects.equals(profileName, other.profileName) &&
+           Objects.equals(profileAvatar, other.profileAvatar) &&
+           Objects.equals(notificationChannel, other.notificationChannel) &&
+           unidentifiedAccessMode == other.unidentifiedAccessMode &&
+           groupsV2Capability == other.groupsV2Capability &&
+           groupsV1MigrationCapability == other.groupsV1MigrationCapability &&
+           insightsBannerTier == other.insightsBannerTier &&
+           Arrays.equals(storageId, other.storageId) &&
+           mentionSetting == other.mentionSetting;
   }
 
+  private static boolean allContentsAreTheSame(@NonNull List<Recipient> a, @NonNull List<Recipient> b) {
+    if (a.size() != b.size()) {
+      return false;
+    }
+
+    for (int i = 0, len = a.size(); i < len; i++) {
+      if (!a.get(i).hasSameContent(b.get(i))) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+
   public static class FallbackPhotoProvider {
     public @NonNull FallbackContactPhoto getPhotoForLocalNumber() {
       return new ResourceContactPhoto(R.drawable.ic_note_34, R.drawable.ic_note_24);

app/src/main/java/org/thoughtcrime/securesms/util/livedata/LiveDataUtil.java

@@ -7,6 +7,7 @@ import androidx.annotation.NonNull;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MediatorLiveData;
 import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.Observer;
 
 import com.annimon.stream.function.Predicate;
 
@@ -169,10 +170,42 @@ public final class LiveDataUtil {
     };
   }
 
+  public static <T> LiveData<T> distinctUntilChanged(@NonNull LiveData<T> source, @NonNull EqualityChecker<T> checker) {
+    final MediatorLiveData<T> outputLiveData = new MediatorLiveData<>();
+    outputLiveData.addSource(source, new Observer<T>() {
+
+      boolean firstChange = true;
+
+      @Override
+      public void onChanged(T nextValue) {
+        T currentValue = outputLiveData.getValue();
+
+        if (currentValue == null && nextValue == null) {
+          return;
+        }
+
+        if (firstChange          ||
+            currentValue == null ||
+            nextValue    == null ||
+            !checker.contentsMatch(currentValue, nextValue))
+        {
+          firstChange = false;
+          outputLiveData.setValue(nextValue);
+        }
+      }
+    });
+
+    return outputLiveData;
+  }
+
   public interface Combine<A, B, R> {
     @NonNull R apply(@NonNull A a, @NonNull B b);
   }
 
+  public interface EqualityChecker<T> {
+    boolean contentsMatch(@NonNull T current, @NonNull T next);
+  }
+
   private static final class CombineLiveData<A, B, R> extends MediatorLiveData<R> {
     private A a;
     private B b;