Encoding and decoding for returned social backups

briar-core/src/main/java/org/briarproject/briar/socialbackup/BackupPayloadEncoderImpl.java

@@ -30,13 +30,14 @@ class BackupPayloadEncoderImpl implements BackupPayloadEncoder {
 	private final ClientHelper clientHelper;
 	private final Provider<AuthenticatedCipher> cipherProvider;
 	private final SecureRandom secureRandom;
-	private final MessageEncoder messageEncoder;
+	private final org.briarproject.briar.api.socialbackup.MessageEncoder
+			messageEncoder;
 
 	@Inject
 	BackupPayloadEncoderImpl(ClientHelper clientHelper,
 			Provider<AuthenticatedCipher> cipherProvider,
 			SecureRandom secureRandom,
-			MessageEncoder messageEncoder) {
+			org.briarproject.briar.api.socialbackup.MessageEncoder messageEncoder) {
 		this.clientHelper = clientHelper;
 		this.cipherProvider = cipherProvider;
 		this.secureRandom = secureRandom;

briar-core/src/main/java/org/briarproject/briar/socialbackup/MessageEncoderImpl.java

@@ -4,17 +4,22 @@ import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.api.socialbackup.BackupPayload;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
 import org.briarproject.briar.api.socialbackup.Shard;
 
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import dagger.Reusable;
+
 import static org.briarproject.briar.socialbackup.MessageType.BACKUP;
 import static org.briarproject.briar.socialbackup.MessageType.SHARD;
 
 @Immutable
 @NotNullByDefault
-class MessageEncoderImpl implements MessageEncoder {
+class MessageEncoderImpl implements
+		org.briarproject.briar.api.socialbackup.MessageEncoder {
 
 	private final ClientHelper clientHelper;
 
@@ -43,6 +48,23 @@ class MessageEncoderImpl implements MessageEncoder {
 		return encodeBody(body);
 	}
 
+	public byte[] encodeReturnShardPayload(ReturnShardPayload returnShardPayload) {
+		Shard shard = returnShardPayload.getShard();
+		BdfList shardList = BdfList.of(
+				SHARD.getValue(),
+				shard.getSecretId(),
+				shard.getShard()
+		);
+		org.briarproject.briar.api.socialbackup.BackupPayload backupPayload = returnShardPayload.getBackupPayload();
+
+		BdfList body = BdfList.of(
+			shardList,
+			returnShardPayload.getBackupPayload().getBytes()
+		);
+
+		return encodeBody(body);
+	}
+
 	private byte[] encodeBody(BdfList body) {
 		try {
 			return clientHelper.toByteArray(body);

briar-core/src/main/java/org/briarproject/briar/socialbackup/MessageParserImpl.java

@@ -3,14 +3,19 @@ package org.briarproject.briar.socialbackup;
 import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.api.socialbackup.BackupPayload;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
 import org.briarproject.briar.api.socialbackup.Shard;
 
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.util.ValidationUtils.checkSize;
+
 @Immutable
 @NotNullByDefault
-class MessageParserImpl implements MessageParser {
+class MessageParserImpl implements
+		org.briarproject.briar.api.socialbackup.MessageParser {
 
 	@Inject
 	MessageParserImpl() {
@@ -30,4 +35,13 @@ class MessageParserImpl implements MessageParser {
 		// Message type, backup payload
 		return new org.briarproject.briar.api.socialbackup.BackupPayload(body.getRaw(1));
 	}
+
+	@Override
+	public ReturnShardPayload parseReturnShardPayload(BdfList body)
+			throws FormatException {
+		checkSize(body, 2);
+		Shard shard = parseShardMessage(body.getList(0));
+		org.briarproject.briar.api.socialbackup.BackupPayload backupPayload = new BackupPayload(body.getRaw(1));
+		return new ReturnShardPayload(shard, backupPayload);
+	}
 }

briar-core/src/main/java/org/briarproject/briar/socialbackup/SocialBackupExchangeManagerImpl.java

@@ -115,7 +115,7 @@ class SocialBackupExchangeManagerImpl implements SocialBackupExchangeManager {
 	@Override
 	public void sendReturnShard(DuplexTransportConnection conn,
 			SecretKey masterKey,
-			boolean verified) throws IOException, DbException {
+			boolean verified, ReturnShardPayload returnShardPayload) throws IOException, DbException {
 		boolean alice = true;
 		// Get the transport connection's input and output streams
 		InputStream in = conn.getReader().getInputStream();
@@ -243,7 +243,7 @@ class SocialBackupExchangeManagerImpl implements SocialBackupExchangeManager {
 			ReturnShardPayload returnShardPayload,
 			long timestamp) throws IOException {
 //		BdfList authorList = clientHelper.toList(author);
-		BdfDictionary props = clientHelper.toDictionary(properties);
+//		BdfDictionary props = clientHelper.toDictionary(properties);
 		Shard shard = returnShardPayload.getShard();
 		BdfList shardList = BdfList.of(shard.getSecretId(), shard.getShard());
 		BdfList payload = BdfList.of(shardList,

briar-core/src/main/java/org/briarproject/briar/socialbackup/SocialBackupManagerImpl.java

@@ -45,6 +45,7 @@ import org.briarproject.briar.api.conversation.DeletionResult;
 import org.briarproject.briar.api.socialbackup.BackupExistsException;
 import org.briarproject.briar.api.socialbackup.BackupMetadata;
 import org.briarproject.briar.api.socialbackup.DarkCrystal;
+import org.briarproject.briar.api.socialbackup.ReturnShardPayload;
 import org.briarproject.briar.api.socialbackup.Shard;
 import org.briarproject.briar.api.socialbackup.BackupPayload;
 import org.briarproject.briar.api.socialbackup.ShardMessageHeader;
@@ -86,8 +87,10 @@ class SocialBackupManagerImpl extends ConversationClientImpl
 	private final BackupMetadataParser backupMetadataParser;
 	private final BackupMetadataEncoder backupMetadataEncoder;
 	private final BackupPayloadEncoder backupPayloadEncoder;
-	private final MessageParser messageParser;
+	private final org.briarproject.briar.api.socialbackup.MessageParser
-	private final MessageEncoder messageEncoder;
+			messageParser;
+	private final org.briarproject.briar.api.socialbackup.MessageEncoder
+			messageEncoder;
 	private final IdentityManager identityManager;
 	private final ContactManager contactManager;
 	private final CryptoComponent crypto;
@@ -106,8 +109,8 @@ class SocialBackupManagerImpl extends ConversationClientImpl
 			BackupMetadataParser backupMetadataParser,
 			BackupMetadataEncoder backupMetadataEncoder,
 			BackupPayloadEncoder backupPayloadEncoder,
-			MessageParser messageParser,
+			org.briarproject.briar.api.socialbackup.MessageParser messageParser,
-			MessageEncoder messageEncoder,
+			org.briarproject.briar.api.socialbackup.MessageEncoder messageEncoder,
 			IdentityManager identityManager,
 			ContactManager contactManager,
 			CryptoComponent crypto,
@@ -231,6 +234,11 @@ class SocialBackupManagerImpl extends ConversationClientImpl
 		return false;
 	}
 
+	public ReturnShardPayload getReturnShardPayload(Transaction txn, ContactId contactId) throws DbException {
+		GroupId groupId = getContactGroup(db.getContact(txn, contactId)).getId();
+		return new ReturnShardPayload(getRemoteShard(txn, groupId), getRemoteBackup(txn, groupId));
+	}
+
 	public boolean amCustodian(Transaction txn, ContactId contactId) {
 		try {
 			GroupId groupId = getContactGroup(db.getContact(txn, contactId)).getId();
@@ -488,6 +496,19 @@ class SocialBackupManagerImpl extends ConversationClientImpl
 		}
 	}
 
+	@Nullable
+	private BackupPayload getRemoteBackup(Transaction txn, GroupId g)
+			throws DbException {
+		try {
+			Pair<MessageId, BdfDictionary> prev =
+					findMessage(txn, g, BACKUP, false);
+			if (prev == null) return null;
+			BdfList body = clientHelper.getMessageAsList(txn, prev.getFirst());
+			return messageParser.parseBackupMessage(body);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
 	private void updateBackup(Transaction txn, List<ContactData> contactData)
 			throws DbException {
 		BackupMetadata backupMetadata = requireNonNull(getBackupMetadata(txn));

briar-core/src/main/java/org/briarproject/briar/socialbackup/SocialBackupModule.java

@@ -82,12 +82,12 @@ public class SocialBackupModule {
 	}
 
 	@Provides
-	MessageEncoder messageEncoder(MessageEncoderImpl messageEncoder) {
+	org.briarproject.briar.api.socialbackup.MessageEncoder messageEncoder(MessageEncoderImpl messageEncoder) {
 		return messageEncoder;
 	}
 
 	@Provides
-	MessageParser messageParser(MessageParserImpl messageParser) {
+	org.briarproject.briar.api.socialbackup.MessageParser messageParser(MessageParserImpl messageParser) {
 		return messageParser;
 	}
 }