make omemo default when all resources support it

src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java

@@ -53,6 +53,7 @@ public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
 
 	public static final String PEP_PREFIX = "eu.siacs.conversations.axolotl";
 	public static final String PEP_DEVICE_LIST = PEP_PREFIX + ".devicelist";
+	public static final String PEP_DEVICE_LIST_NOTIFY = PEP_DEVICE_LIST + "+notify";
 	public static final String PEP_BUNDLES = PEP_PREFIX + ".bundles";
 	public static final String PEP_VERIFICATION = PEP_PREFIX + ".verification";
 

src/main/java/eu/siacs/conversations/entities/Conversation.java

@@ -27,6 +27,7 @@ import eu.siacs.conversations.xmpp.chatstate.ChatState;
 import eu.siacs.conversations.xmpp.jid.InvalidJidException;
 import eu.siacs.conversations.xmpp.jid.Jid;
 
+
 public class Conversation extends AbstractEntity implements Blockable {
 	public static final String TABLENAME = "conversations";
 
@@ -678,12 +679,12 @@ public class Conversation extends AbstractEntity implements Blockable {
 		final AxolotlService axolotlService = getAccount().getAxolotlService();
 		int next = this.getIntAttribute(ATTRIBUTE_NEXT_ENCRYPTION, -1);
 		if (next == -1) {
-			if (Config.X509_VERIFICATION) {
-				if (axolotlService != null && axolotlService.isConversationAxolotlCapable(this)) {
-					return Message.ENCRYPTION_AXOLOTL;
-				} else {
-					return Message.ENCRYPTION_NONE;
-				}
+			if (Config.supportOmemo()
+					&& axolotlService != null
+					&& mode == MODE_SINGLE
+					&& axolotlService.isConversationAxolotlCapable(this)
+					&& getContact().getPresences().allOrNonSupport(AxolotlService.PEP_DEVICE_LIST_NOTIFY)) {
+				return Message.ENCRYPTION_AXOLOTL;
 			}
 			int outgoing = this.getMostRecentlyUsedOutgoingEncryption();
 			if (outgoing == Message.ENCRYPTION_NONE) {
@@ -695,7 +696,7 @@ public class Conversation extends AbstractEntity implements Blockable {
 
 		if (!Config.supportUnencrypted() && next <= 0) {
 			if (Config.supportOmemo()
-					&& (axolotlService != null && axolotlService.isConversationAxolotlCapable(this) || !Config.multipleEncryptionChoices())) {
+					&& ((axolotlService != null && axolotlService.isConversationAxolotlCapable(this)) || !Config.multipleEncryptionChoices())) {
 				return Message.ENCRYPTION_AXOLOTL;
 			} else if (Config.supportOtr() && mode == MODE_SINGLE) {
 				return Message.ENCRYPTION_OTR;

src/main/java/eu/siacs/conversations/entities/Presence.java

@@ -40,11 +40,11 @@ public class Presence implements Comparable {
 		}
 	}
 
-	protected final Status status;
-	protected ServiceDiscoveryResult disco;
-	protected final String ver;
-	protected final String hash;
-	protected final String message;
+	private final Status status;
+	private ServiceDiscoveryResult disco;
+	private final String ver;
+	private final String hash;
+	private final String message;
 
 	private Presence(Status status, String ver, String hash, String message) {
 		this.status = status;
@@ -79,7 +79,15 @@ public class Presence implements Comparable {
 		return this.hash;
 	}
 
+	public String getMessage() {
+		return this.message;
+	}
+
 	public void setServiceDiscoveryResult(ServiceDiscoveryResult disco) {
 		this.disco = disco;
 	}
+
+	public ServiceDiscoveryResult getServiceDiscoveryResult() {
+		return disco;
+	}
 }

src/main/java/eu/siacs/conversations/entities/Presences.java

@@ -64,11 +64,24 @@ public class Presences {
 		ArrayList<String> messages = new ArrayList<>();
 		synchronized (this.presences) {
 			for(Presence presence : this.presences.values()) {
-				if (presence.message != null && !presence.message.trim().isEmpty()) {
-					messages.add(presence.message.trim());
+				String message = presence.getMessage();
+				if (message != null && !message.trim().isEmpty()) {
+					messages.add(message.trim());
 				}
 			}
 		}
 		return messages;
 	}
+
+	public boolean allOrNonSupport(String namespace) {
+		synchronized (this.presences) {
+			for(Presence presence : this.presences.values()) {
+				ServiceDiscoveryResult disco = presence.getServiceDiscoveryResult();
+				if (disco == null || !disco.getFeatures().contains(namespace)) {
+					return false;
+				}
+			}
+		}
+		return true;
+	}
 }

src/main/java/eu/siacs/conversations/generator/AbstractGenerator.java

@@ -33,7 +33,7 @@ public abstract class AbstractGenerator {
 			"urn:xmpp:ping",
 			"jabber:iq:version",
 			"http://jabber.org/protocol/chatstates",
-			AxolotlService.PEP_DEVICE_LIST+"+notify"};
+			AxolotlService.PEP_DEVICE_LIST_NOTIFY};
 	private final String[] MESSAGE_CONFIRMATION_FEATURES = {
 			"urn:xmpp:chat-markers:0",
 			"urn:xmpp:receipts"