Rewrote the bundle reading and writing code to eliminate copying. Signatures and digests are now calculated on the fly as the data is read or written. This is a little bit tricky in the case of reading because ReaderImpl uses a lookahead byte, so the signature and message digest need to lag one byte behind.

api/net/sf/briar/api/protocol/Batch.java

@@ -8,12 +8,6 @@ public interface Batch {
 	/** Returns the batch's unique identifier. */
 	BatchId getId();
 
-	/** Returns the size of the serialised batch in bytes. */
-	long getSize();
-
 	/** Returns the messages contained in the batch. */
 	Iterable<Message> getMessages();
-
-	/** Returns the sender's signature over the contents of the batch. */
-	byte[] getSignature();
 }

api/net/sf/briar/api/protocol/BatchBuilder.java

@@ -1,16 +0,0 @@
-package net.sf.briar.api.protocol;
-
-import java.io.IOException;
-import java.security.GeneralSecurityException;
-
-public interface BatchBuilder {
-
-	/** Adds a message to the batch. */
-	void addMessage(Message m);
-
-	/** Sets the sender's signature over the contents of the batch. */
-	void setSignature(byte[] sig);
-
-	/** Builds and returns the batch. */
-	Batch build() throws IOException, GeneralSecurityException;
-}

api/net/sf/briar/api/protocol/BundleReader.java

@@ -9,9 +9,6 @@ import java.security.GeneralSecurityException;
  */
 public interface BundleReader {
 
-	/** Returns the size of the serialised bundle in bytes. */
-	long getSize() throws IOException;
-
 	/** Returns the bundle's header. */
 	Header getHeader() throws IOException, GeneralSecurityException;
 
@@ -21,5 +18,5 @@ public interface BundleReader {
 	Batch getNextBatch() throws IOException, GeneralSecurityException;
 
 	/** Finishes reading the bundle. */
-	void close() throws IOException;
+	void finish() throws IOException;
 }

api/net/sf/briar/api/protocol/BundleWriter.java

@@ -1,6 +1,8 @@
 package net.sf.briar.api.protocol;
 
 import java.io.IOException;
+import java.security.GeneralSecurityException;
+import java.util.Map;
 
 /**
  * An interface for writing a bundle of acknowledgements, subscriptions,
@@ -8,15 +10,18 @@ import java.io.IOException;
  */
 public interface BundleWriter {
 
-	/** Returns the bundle's capacity in bytes. */
-	long getCapacity() throws IOException;
+	/** Returns the bundle's remaining capacity in bytes. */
+	long getRemainingCapacity() throws IOException;
 
-	/** Adds a header to the bundle. */
-	void addHeader(Header h) throws IOException;
+	/** Adds a header to the bundle and returns its identifier. */
+	BundleId addHeader(Iterable<BatchId> acks, Iterable<GroupId> subs,
+			Map<String, String> transports) throws IOException,
+			GeneralSecurityException;
 
-	/** Adds a batch of messages to the bundle. */
-	void addBatch(Batch b) throws IOException;
+	/** Adds a batch to the bundle and returns its identifier. */
+	BatchId addBatch(Iterable<Message> messages) throws IOException,
+	GeneralSecurityException;
 
 	/** Finishes writing the bundle. */
-	void close() throws IOException;
+	void finish() throws IOException;
 }

api/net/sf/briar/api/protocol/Header.java

@@ -11,9 +11,6 @@ public interface Header {
 	// FIXME: Remove BundleId when refactoring is complete
 	BundleId getId();
 
-	/** Returns the size of the serialised header in bytes. */
-	long getSize();
-
 	/** Returns the acknowledgements contained in the header. */
 	Set<BatchId> getAcks();
 
@@ -22,7 +19,4 @@ public interface Header {
 
 	/** Returns the transport details contained in the header. */
 	Map<String, String> getTransports();
-
-	/** Returns the sender's signature over the contents of the header. */
-	byte[] getSignature();
 }

api/net/sf/briar/api/protocol/HeaderBuilder.java

@@ -1,23 +0,0 @@
-package net.sf.briar.api.protocol;
-
-import java.io.IOException;
-import java.security.GeneralSecurityException;
-import java.util.Map;
-
-public interface HeaderBuilder {
-
-	/** Adds acknowledgements to the header. */
-	void addAcks(Iterable<BatchId> acks);
-
-	/** Adds subscriptions to the header. */
-	void addSubscriptions(Iterable<GroupId> subs);
-
-	/** Adds transport details to the header. */
-	void addTransports(Map<String, String> transports);
-
-	/** Sets the sender's signature over the contents of the header. */
-	void setSignature(byte[] sig);
-
-	/** Builds and returns the header. */
-	Header build() throws IOException, GeneralSecurityException;
-}

api/net/sf/briar/api/protocol/MessageFactory.java

@@ -3,5 +3,5 @@ package net.sf.briar.api.protocol;
 public interface MessageFactory {
 
 	Message createMessage(MessageId id, MessageId parent, GroupId group,
-			AuthorId author, long timestamp, byte[] body);
+			AuthorId author, long timestamp, byte[] raw);
 }

api/net/sf/briar/api/serial/Raw.java

@@ -1,5 +1,9 @@
 package net.sf.briar.api.serial;
 
+/**
+ * Generic interface for any object that knows how to serialise itself as a
+ * raw byte array.
+ */
 public interface Raw {
 
 	byte[] getBytes();