check disco feature on entity

src/main/java/im/conversations/android/database/dao/DiscoDao.java

@@ -126,6 +126,12 @@ public abstract class DiscoDao {
     @Query("SELECT id FROM disco WHERE accountId=:accountId AND capsHash=:capsHash")
     protected abstract Long getDiscoIdByCapsHash(final long accountId, final byte[] capsHash);
 
+    @Query(
+            "SELECT EXISTS (SELECT disco_item.id FROM disco_item JOIN disco_feature on"
+                    + " disco_item.discoId=disco_feature.discoId WHERE accountId=:account AND"
+                    + " address=:entity AND feature=:feature)")
+    public abstract boolean hasFeature(final long account, final Jid entity, final String feature);
+
     public static class DiscoItemWithParent {
         public long accountId;
         public Jid address;

src/main/java/im/conversations/android/xmpp/XmppConnection.java

@@ -1986,7 +1986,7 @@ public class XmppConnection implements Runnable {
 
     private void enableAdvancedStreamFeatures() {
         if (getManager(DiscoManager.class)
-                        .isFeature(connectionAddress.getDomain(), Namespace.CARBONS)
+                        .hasFeature(connectionAddress.getDomain(), Namespace.CARBONS)
                 && !this.carbonsEnabled) {
             sendEnableCarbons();
         }

src/main/java/im/conversations/android/xmpp/manager/DiscoManager.java

@@ -102,7 +102,7 @@ public class DiscoManager extends AbstractManager {
                 MoreExecutors.directExecutor());
     }
 
-    public boolean isFeature(final Jid entity, final String feature) {
-        return true;
+    public boolean hasFeature(final Jid entity, final String feature) {
+        return getDatabase().discoDao().hasFeature(getAccount().id, entity, feature);
     }
 }

src/main/java/im/conversations/android/xmpp/processor/BindProcessor.java

@@ -1,10 +1,12 @@
 package im.conversations.android.xmpp.processor;
 
 import android.content.Context;
+import eu.siacs.conversations.xml.Namespace;
 import eu.siacs.conversations.xmpp.Jid;
 import im.conversations.android.xmpp.XmppConnection;
 import im.conversations.android.xmpp.manager.BlockingManager;
 import im.conversations.android.xmpp.manager.BookmarkManager;
+import im.conversations.android.xmpp.manager.DiscoManager;
 import im.conversations.android.xmpp.manager.RosterManager;
 import java.util.function.Consumer;
 
@@ -31,8 +33,10 @@ public class BindProcessor extends XmppConnection.Delegate implements Consumer<J
 
         getManager(RosterManager.class).fetch();
 
-        // TODO check feature before fetching
-        getManager(BlockingManager.class).fetch();
+        if (getManager(DiscoManager.class)
+                .hasFeature(account.address.getDomain(), Namespace.BLOCKING)) {
+            getManager(BlockingManager.class).fetch();
+        }
 
         getManager(BookmarkManager.class).fetch();