Separated Android code and core code into distinct Eclipse projects.

This should make it possible to develop the core in Eclipse without the ADT.

briar-core/.classpath

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/J2SE-1.5"/>
+	<classpathentry kind="lib" path="libs/activation.jar"/>
+	<classpathentry kind="lib" path="libs/bluecove-2.1.0-briar.jar"/>
+	<classpathentry kind="lib" path="libs/bluecove-gpl-2.1.0.jar"/>
+	<classpathentry kind="lib" path="libs/commons-io-2.0.1.jar"/>
+	<classpathentry kind="lib" path="libs/guice-3.0-no_aop.jar"/>
+	<classpathentry kind="lib" path="libs/h2small-1.3.161.jar"/>
+	<classpathentry kind="lib" path="libs/javax.inject.jar"/>
+	<classpathentry kind="lib" path="libs/jna-3.5.1.jar"/>
+	<classpathentry kind="lib" path="libs/jnotify-0.93.jar"/>
+	<classpathentry kind="lib" path="libs/jssc-0.9-briar.jar"/>
+	<classpathentry kind="lib" path="libs/platform-3.5.1.jar"/>
+	<classpathentry kind="lib" path="libs/sc-light-jdk15on-1.47.0.3-SNAPSHOT.jar"/>
+	<classpathentry kind="lib" path="libs/scpkix-jdk15on-1.47.0.3-SNAPSHOT.jar"/>
+	<classpathentry kind="lib" path="libs/scprov-jdk15on-1.47.0.3-SNAPSHOT.jar"/>
+	<classpathentry kind="lib" path="libs/silvertunnel.org-netlib-0.14-briar.jar"/>
+	<classpathentry kind="lib" path="libs/weupnp-0.1.1.jar"/>
+	<classpathentry kind="lib" path="android.jar"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

briar-core/.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>briar-core</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

briar-core/src/build.xml

@@ -0,0 +1,25 @@
+<project name='prototype' default='compile'>
+	<fileset id='prototype-jars' dir='../libs'>
+		<include name='*.jar'/>
+	</fileset>
+	<path id='android-jar'>
+		<pathelement location='../android.jar'/>
+	</path>
+	<path id='prototype-classes'>
+		<pathelement location='../build'/>
+	</path>
+	<target name='clean'>
+		<delete dir='../build'/>
+	</target>
+	<target name='compile'>
+		<mkdir dir='../build'/>
+		<javac srcdir='.' destdir='../build' source='1.5'
+			includeantruntime='false' debug='off'>
+			<classpath>
+				<fileset refid='prototype-jars'/>
+				<path refid='android-jar'/>
+				<path refid='prototype-classes'/>
+			</classpath>
+		</javac>
+	</target>
+</project>

briar-core/src/net/sf/briar/api/Bytes.java

@@ -0,0 +1,34 @@
+package net.sf.briar.api;
+
+import java.util.Arrays;
+
+/** A wrapper around a byte array, to allow it to be stored in maps etc. */
+public class Bytes {
+
+	private final byte[] bytes;
+
+	private int hashCode = -1;
+
+	public Bytes(byte[] bytes) {
+		this.bytes = bytes;
+	}
+
+	public byte[] getBytes() {
+		return bytes;
+	}
+
+	@Override
+	public int hashCode() {
+		// Thread-safe because if two or more threads check and update the
+		// value, they'll calculate the same value
+		if(hashCode == -1) hashCode = Arrays.hashCode(bytes);
+		return hashCode;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if(o instanceof Bytes)
+			return Arrays.equals(bytes, ((Bytes) o).bytes);
+		return false;
+	}
+}

briar-core/src/net/sf/briar/api/ContactId.java

@@ -0,0 +1,29 @@
+package net.sf.briar.api;
+
+/**
+ * Type-safe wrapper for an integer that uniquely identifies a contact within
+ * the scope of a single node.
+ */
+public class ContactId {
+
+	private final int id;
+
+	public ContactId(int id) {
+		this.id = id;
+	}
+
+	public int getInt() {
+		return id;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if(o instanceof ContactId) return id == ((ContactId) o).id;
+		return false;
+	}
+
+	@Override
+	public int hashCode() {
+		return id;
+	}
+}

briar-core/src/net/sf/briar/api/FormatException.java

@@ -0,0 +1,9 @@
+package net.sf.briar.api;
+
+import java.io.IOException;
+
+/** An exception that indicates an unrecoverable formatting error. */
+public class FormatException extends IOException {
+
+	private static final long serialVersionUID = 2274966775687766337L;
+}

briar-core/src/net/sf/briar/api/Rating.java

@@ -0,0 +1,6 @@
+package net.sf.briar.api;
+
+/** The ratings that may be applied to an author in peer moderation. */
+public enum Rating {
+	BAD, UNRATED, GOOD
+}

briar-core/src/net/sf/briar/api/TransportConfig.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api;
+
+import java.util.Hashtable;
+import java.util.Map;
+
+public class TransportConfig extends Hashtable<String, String> {
+
+	private static final long serialVersionUID = 2330384620787778596L;
+
+	public TransportConfig(Map<String, String> c) {
+		super(c);
+	}
+
+	public TransportConfig() {
+		super();
+	}
+}

briar-core/src/net/sf/briar/api/TransportProperties.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api;
+
+import java.util.Hashtable;
+import java.util.Map;
+
+public class TransportProperties extends Hashtable<String, String> {
+
+	private static final long serialVersionUID = 7533739534204953625L;
+
+	public TransportProperties(Map<String, String> p) {
+		super(p);
+	}
+
+	public TransportProperties() {
+		super();
+	}
+}

briar-core/src/net/sf/briar/api/android/AndroidExecutor.java

@@ -0,0 +1,16 @@
+package net.sf.briar.api.android;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+
+/**
+ * Enables background threads to make Android API calls that must be made from
+ * a thread with a message queue.
+ */
+public interface AndroidExecutor {
+
+	/** Runs the given task on a thread with a message queue. */
+	<V> V run(Callable<V> c) throws InterruptedException, ExecutionException;
+
+	void shutdown();
+}

briar-core/src/net/sf/briar/api/clock/Clock.java

@@ -0,0 +1,11 @@
+package net.sf.briar.api.clock;
+
+/**
+ * An interface for time-related system functions that allows them to be
+ * replaced for testing.
+ */
+public interface Clock {
+
+	/** @see {@link java.lang.System#currentTimeMillis()} */
+	long currentTimeMillis();
+}

briar-core/src/net/sf/briar/api/clock/SystemClock.java

@@ -0,0 +1,9 @@
+package net.sf.briar.api.clock;
+
+/** Default clock implementation. */
+public class SystemClock implements Clock {
+
+	public long currentTimeMillis() {
+		return System.currentTimeMillis();
+	}
+}

briar-core/src/net/sf/briar/api/clock/SystemTimer.java

@@ -0,0 +1,29 @@
+package net.sf.briar.api.clock;
+
+import java.util.TimerTask;
+
+/** Default timer implementation. */
+public class SystemTimer implements Timer {
+
+	private final java.util.Timer timer = new java.util.Timer();
+
+	public void cancel() {
+		timer.cancel();
+	}
+
+	public int purge() {
+		return timer.purge();
+	}
+
+	public void schedule(TimerTask task, long delay) {
+		timer.schedule(task, delay);
+	}
+
+	public void schedule(TimerTask task, long delay, long period) {
+		timer.schedule(task, delay, period);
+	}
+
+	public void scheduleAtFixedRate(TimerTask task, long delay, long period) {
+		timer.scheduleAtFixedRate(task, delay, period);
+	}
+}

briar-core/src/net/sf/briar/api/clock/Timer.java

@@ -0,0 +1,27 @@
+package net.sf.briar.api.clock;
+
+import java.util.TimerTask;
+
+/**
+ * A wrapper around a {@link java.util.Timer} that allows it to be replaced for
+ * testing.
+ */
+public interface Timer {
+
+	/** @see {@link java.util.Timer#cancel()} */
+	void cancel();
+
+	/** @see {@link java.util.Timer#purge()} */
+	int purge();
+
+	/** @see {@link java.util.Timer#schedule(TimerTask, long)} */
+	void schedule(TimerTask task, long delay);
+
+	/** @see {@link java.util.Timer#schedule(TimerTask, long, long)} */
+	void schedule(TimerTask task, long delay, long period);
+
+	/**
+	 * @see {@link java.util.Timer#scheduleAtFixedRate(TimerTask, long, long)}
+	 */
+	void scheduleAtFixedRate(TimerTask task, long delay, long period);
+}

briar-core/src/net/sf/briar/api/crypto/AuthenticatedCipher.java

@@ -0,0 +1,29 @@
+package net.sf.briar.api.crypto;
+
+import java.security.InvalidKeyException;
+import java.security.Key;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.IllegalBlockSizeException;
+
+/**
+ * A wrapper for a provider-dependent cipher class, since javax.crypto.Cipher
+ * doesn't support additional authenticated data until Java 7.
+ */
+public interface AuthenticatedCipher {
+
+	/**
+	 * Initializes this cipher with a key, an initialisation vector (IV) and
+	 * additional authenticated data (AAD).
+	 */
+	void init(int opmode, Key key, byte[] iv, byte[] aad)
+			throws InvalidKeyException;
+
+	/** Encrypts or decrypts data in a single-part operation. */
+	int doFinal(byte[] input, int inputOff, int len, byte[] output,
+			int outputOff) throws IllegalBlockSizeException,
+			BadPaddingException;
+
+	/** Returns the length of the message authenticated code (MAC) in bytes. */
+	int getMacLength();
+}

briar-core/src/net/sf/briar/api/crypto/CryptoComponent.java

@@ -0,0 +1,81 @@
+package net.sf.briar.api.crypto;
+
+import java.security.GeneralSecurityException;
+import java.security.KeyPair;
+import java.security.SecureRandom;
+import java.security.Signature;
+
+import javax.crypto.Cipher;
+
+public interface CryptoComponent {
+
+	/**
+	 * Derives a tag key from the given temporary secret.
+	 * @param alice indicates whether the key is for connections initiated by
+	 * Alice or Bob.
+	 */
+	ErasableKey deriveTagKey(byte[] secret, boolean alice);
+
+	/**
+	 * Derives a frame key from the given temporary secret and connection
+	 * number.
+	 * @param alice indicates whether the key is for a connection initiated by
+	 * Alice or Bob.
+	 * @param initiator indicates whether the key is for the initiator's or the
+	 * responder's side of the connection.
+	 */
+	ErasableKey deriveFrameKey(byte[] secret, long connection, boolean alice,
+			boolean initiator);
+
+	/**
+	 * Derives an initial shared secret from two public keys and one of the
+	 * corresponding private keys.
+	 * @param alice indicates whether the private key belongs to Alice or Bob.
+	 */
+	byte[] deriveInitialSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
+			boolean alice) throws GeneralSecurityException;
+
+	/**
+	 * Generates a random invitation code.
+	 */
+	int generateInvitationCode();
+
+	/**
+	 * Derives two confirmation codes from the given initial shared secret. The
+	 * first code is for Alice to give to Bob; the second is for Bob to give to
+	 * Alice.
+	 */
+	int[] deriveConfirmationCodes(byte[] secret);
+
+	/**
+	 * Derives a temporary secret for the given period from the previous
+	 * period's temporary secret.
+	 */
+	byte[] deriveNextSecret(byte[] secret, long period);
+
+	/** Encodes the pseudo-random tag that is used to recognise a connection. */
+	void encodeTag(byte[] tag, Cipher tagCipher, ErasableKey tagKey,
+			long connection);
+
+	KeyPair generateAgreementKeyPair();
+
+	KeyParser getAgreementKeyParser();
+
+	KeyPair generateSignatureKeyPair();
+
+	KeyParser getSignatureKeyParser();
+
+	ErasableKey generateTestKey();
+
+	MessageDigest getMessageDigest();
+
+	PseudoRandom getPseudoRandom(int seed1, int seed2);
+
+	SecureRandom getSecureRandom();
+
+	Cipher getTagCipher();
+
+	AuthenticatedCipher getFrameCipher();
+
+	Signature getSignature();
+}

briar-core/src/net/sf/briar/api/crypto/ErasableKey.java

@@ -0,0 +1,12 @@
+package net.sf.briar.api.crypto;
+
+import javax.crypto.SecretKey;
+
+public interface ErasableKey extends SecretKey {
+
+	/** Returns a copy of the key. */
+	ErasableKey copy();
+
+	/** Erases the key from memory. */
+	void erase();
+}

briar-core/src/net/sf/briar/api/crypto/KeyManager.java

@@ -0,0 +1,31 @@
+package net.sf.briar.api.crypto;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.protocol.TransportId;
+import net.sf.briar.api.transport.ConnectionContext;
+import net.sf.briar.api.transport.ContactTransport;
+
+public interface KeyManager {
+
+	/**
+	 * Starts the key manager and returns true if it started successfully. This
+	 * method must be called after the database has been opened.
+	 */
+	boolean start();
+
+	/** Stops the key manager. */
+	void stop();
+
+	/**
+	 * Returns a connection context for connecting to the given contact over
+	 * the given transport, or null if an error occurs or the contact does not
+	 * support the transport.
+	 */
+	ConnectionContext getConnectionContext(ContactId c, TransportId t);
+
+	/**
+	 * Called whenever a contact transport has been added. The initial secret
+	 * is erased before returning.
+	 */
+	void contactTransportAdded(ContactTransport ct, byte[] initialSecret);
+}

briar-core/src/net/sf/briar/api/crypto/KeyParser.java

@@ -0,0 +1,9 @@
+package net.sf.briar.api.crypto;
+
+import java.security.PublicKey;
+import java.security.spec.InvalidKeySpecException;
+
+public interface KeyParser {
+
+	PublicKey parsePublicKey(byte[] encodedKey) throws InvalidKeySpecException;
+}

briar-core/src/net/sf/briar/api/crypto/MessageDigest.java

@@ -0,0 +1,32 @@
+package net.sf.briar.api.crypto;
+
+/**
+ * A wrapper around a {@link java.security.MessageDigest} that allows it to be
+ * replaced for testing.
+ */
+public interface MessageDigest {
+
+	/** @see {@link java.security.MessageDigest#digest()} */
+	byte[] digest();
+
+	/** @see {@link java.security.MessageDigest#digest(byte[])} */
+	byte[] digest(byte[] input);
+
+	/** @see {@link java.security.MessageDigest#digest(byte[], int, int)} */
+	int digest(byte[] buf, int offset, int len);
+
+	/** @see {@link java.security.MessageDigest#getDigestLength()} */
+	int getDigestLength();
+
+	/** @see {@link java.security.MessageDigest#reset()} */
+	void reset();
+
+	/** @see {@link java.security.MessageDigest#update(byte)} */
+	void update(byte input);
+
+	/** @see {@link java.security.MessageDigest#update(byte[])} */
+	void update(byte[] input);
+
+	/** @see {@link java.security.MessageDigest#update(byte[], int, int)} */
+	void update(byte[] input, int offset, int len);
+}

briar-core/src/net/sf/briar/api/crypto/Password.java

@@ -0,0 +1,14 @@
+package net.sf.briar.api.crypto;
+
+/**
+ * Encapsulates a password. Implementations may keep the password encrypted in
+ * memory to reduce the chances of writing it to the swapfile in plaintext.
+ */
+public interface Password {
+
+	/**
+	 * Returns the password as a character array, which should be filled with
+	 * zeroes as soon as it has been used.
+	 */
+	char[] getPassword();
+}

briar-core/src/net/sf/briar/api/crypto/PseudoRandom.java

@@ -0,0 +1,6 @@
+package net.sf.briar.api.crypto;
+
+public interface PseudoRandom {
+
+	byte[] nextBytes(int bytes);
+}

briar-core/src/net/sf/briar/api/db/DatabaseComponent.java

@@ -0,0 +1,225 @@
+package net.sf.briar.api.db;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Map;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.Rating;
+import net.sf.briar.api.TransportConfig;
+import net.sf.briar.api.TransportProperties;
+import net.sf.briar.api.db.event.DatabaseListener;
+import net.sf.briar.api.protocol.Ack;
+import net.sf.briar.api.protocol.AuthorId;
+import net.sf.briar.api.protocol.Batch;
+import net.sf.briar.api.protocol.Group;
+import net.sf.briar.api.protocol.GroupId;
+import net.sf.briar.api.protocol.Message;
+import net.sf.briar.api.protocol.MessageId;
+import net.sf.briar.api.protocol.Offer;
+import net.sf.briar.api.protocol.RawBatch;
+import net.sf.briar.api.protocol.Request;
+import net.sf.briar.api.protocol.SubscriptionUpdate;
+import net.sf.briar.api.protocol.Transport;
+import net.sf.briar.api.protocol.TransportId;
+import net.sf.briar.api.protocol.TransportUpdate;
+import net.sf.briar.api.transport.ContactTransport;
+import net.sf.briar.api.transport.TemporarySecret;
+
+/**
+ * Encapsulates the database implementation and exposes high-level operations
+ * to other components.
+ */
+public interface DatabaseComponent {
+
+	/**
+	 * Opens the database.
+	 * @param resume true to reopen an existing database or false to create a
+	 * new one.
+	 */
+	void open(boolean resume) throws DbException, IOException;
+
+	/** Waits for any open transactions to finish and closes the database. */
+	void close() throws DbException, IOException;
+
+	/** Adds a listener to be notified when database events occur. */
+	void addListener(DatabaseListener d);
+
+	/** Removes a listener. */
+	void removeListener(DatabaseListener d);
+
+	/**
+	 * Adds a new contact to the database and returns an ID for the contact.
+	 */
+	ContactId addContact() throws DbException;
+
+	/** Adds a contact transport to the database. */
+	void addContactTransport(ContactTransport ct) throws DbException;
+
+	/** Adds a locally generated group message to the database. */
+	void addLocalGroupMessage(Message m) throws DbException;
+
+	/** Adds a locally generated private message to the database. */
+	void addLocalPrivateMessage(Message m, ContactId c) throws DbException;
+
+	/**
+	 * Stores the given temporary secrets and deletes any secrets that have
+	 * been made obsolete.
+	 */
+	void addSecrets(Collection<TemporarySecret> secrets) throws DbException;
+
+	/**
+	 * Generates an acknowledgement for the given contact. Returns null if
+	 * there are no batches to acknowledge.
+	 */
+	Ack generateAck(ContactId c, int maxBatches) throws DbException;
+
+	/**
+	 * Generates a batch of messages for the given contact. Returns null if
+	 * there are no sendable messages that fit in the given capacity.
+	 */
+	RawBatch generateBatch(ContactId c, int capacity) throws DbException;
+
+	/**
+	 * Generates a batch of messages for the given contact from the given
+	 * collection of requested messages. Any messages that were either added to
+	 * the batch, or were considered but are no longer sendable to the contact,
+	 * are removed from the collection of requested messages before returning.
+	 * Returns null if there are no sendable messages that fit in the given
+	 * capacity.
+	 */
+	RawBatch generateBatch(ContactId c, int capacity,
+			Collection<MessageId> requested) throws DbException;
+
+	/**
+	 * Generates an offer for the given contact. Returns null if there are no
+	 * messages to offer.
+	 */
+	Offer generateOffer(ContactId c, int maxMessages) throws DbException;
+
+	/**
+	 * Generates a subscription update for the given contact. Returns null if
+	 * an update is not due.
+	 */
+	SubscriptionUpdate generateSubscriptionUpdate(ContactId c)
+			throws DbException;
+
+	/**
+	 * Generates a transport update for the given contact. Returns null if an
+	 * update is not due.
+	 */
+	TransportUpdate generateTransportUpdate(ContactId c) throws DbException;
+
+	/** Returns the configuration for the given transport. */
+	TransportConfig getConfig(TransportId t) throws DbException;
+
+	/** Returns the IDs of all contacts. */
+	Collection<ContactId> getContacts() throws DbException;
+
+	/** Returns the local transport properties for the given transport. */
+	TransportProperties getLocalProperties(TransportId t) throws DbException;
+
+	/** Returns all local transports. */
+	Collection<Transport> getLocalTransports() throws DbException;
+
+	/** Returns the headers of all messages in the given group. */
+	Collection<MessageHeader> getMessageHeaders(GroupId g) throws DbException;
+
+	/** Returns the user's rating for the given author. */
+	Rating getRating(AuthorId a) throws DbException;
+
+	/** Returns all remote transport properties for the given transport. */
+	Map<ContactId, TransportProperties> getRemoteProperties(TransportId t)
+			throws DbException;
+
+	/** Returns all temporary secrets. */
+	Collection<TemporarySecret> getSecrets() throws DbException;
+
+	/** Returns the set of groups to which the user subscribes. */
+	Collection<Group> getSubscriptions() throws DbException;
+
+	/** Returns the number of unread messages in each subscribed group. */
+	Map<GroupId, Integer> getUnreadMessageCounts() throws DbException;
+
+	/** Returns the contacts to which the given group is visible. */
+	Collection<ContactId> getVisibility(GroupId g) throws DbException;
+
+	/** Returns true if any messages are sendable to the given contact. */
+	boolean hasSendableMessages(ContactId c) throws DbException;
+
+	/**
+	 * Increments the outgoing connection counter for the given contact
+	 * transport in the given rotation period and returns the old value.
+	 */
+	long incrementConnectionCounter(ContactId c, TransportId t, long period)
+			throws DbException;
+
+	/**
+	 * Merges the given configuration with existing configuration for the
+	 * given transport.
+	 */
+	void mergeConfig(TransportId t, TransportConfig c) throws DbException;
+
+	/**
+	 * Merges the given properties with the existing local properties for the
+	 * given transport.
+	 */
+	void mergeLocalProperties(TransportId t, TransportProperties p)
+			throws DbException;
+
+	/** Processes an acknowledgement from the given contact. */
+	void receiveAck(ContactId c, Ack a) throws DbException;
+
+	/** Processes a batch of messages from the given contact. */
+	void receiveBatch(ContactId c, Batch b) throws DbException;
+
+	/**
+	 * Processes an offer from the given contact and generates a request for
+	 * any messages in the offer that the contact should send. To prevent
+	 * contacts from using offers to test for subscriptions that are not
+	 * visible to them, any messages belonging to groups that are not visible
+	 * to the contact are requested just as though they were not present in the
+	 * database.
+	 */
+	Request receiveOffer(ContactId c, Offer o) throws DbException;
+
+	/** Processes a subscription update from the given contact. */
+	void receiveSubscriptionUpdate(ContactId c, SubscriptionUpdate s)
+			throws DbException;
+
+	/** Processes a transport update from the given contact. */
+	void receiveTransportUpdate(ContactId c, TransportUpdate t)
+			throws DbException;
+
+	/** Removes a contact (and all associated state) from the database. */
+	void removeContact(ContactId c) throws DbException;
+
+	/**
+	 * Sets the connection reordering window for the given contact transport
+	 * in the given rotation period.
+	 */
+	void setConnectionWindow(ContactId c, TransportId t, long period,
+			long centre, byte[] bitmap) throws DbException;
+
+	/** Records the user's rating for the given author. */
+	void setRating(AuthorId a, Rating r) throws DbException;
+
+	/** Records the given messages as having been seen by the given contact. */
+	void setSeen(ContactId c, Collection<MessageId> seen) throws DbException;
+
+	/**
+	 * Makes the given group visible to the given set of contacts and invisible
+	 * to any other contacts.
+	 */
+	void setVisibility(GroupId g, Collection<ContactId> visible)
+			throws DbException;
+
+	/** Subscribes to the given group. */
+	void subscribe(Group g) throws DbException;
+
+	/**
+	 * Unsubscribes from the given group. Any messages belonging to the group
+	 * are deleted from the database.
+	 */
+	void unsubscribe(GroupId g) throws DbException;
+}

briar-core/src/net/sf/briar/api/db/DatabaseConfig.java

@@ -0,0 +1,14 @@
+package net.sf.briar.api.db;
+
+import java.io.File;
+
+import net.sf.briar.api.crypto.Password;
+
+public interface DatabaseConfig {
+
+	File getDataDirectory();
+
+	Password getPassword();
+
+	long getMaxSize();
+}

briar-core/src/net/sf/briar/api/db/DatabaseExecutor.java

@@ -0,0 +1,15 @@
+package net.sf.briar.api.db;
+
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import com.google.inject.BindingAnnotation;
+
+/** Annotation for injecting the executor for database tasks. */
+@BindingAnnotation
+@Target({ PARAMETER })
+@Retention(RUNTIME)
+public @interface DatabaseExecutor {}

briar-core/src/net/sf/briar/api/db/DbClosedException.java

@@ -0,0 +1,7 @@
+package net.sf.briar.api.db;
+
+/** Thrown when a database operation is attempted and the database is closed. */
+public class DbClosedException extends DbException {
+
+	private static final long serialVersionUID = -3679248177625310653L;
+}

briar-core/src/net/sf/briar/api/db/DbException.java

@@ -0,0 +1,14 @@
+package net.sf.briar.api.db;
+
+public class DbException extends Exception {
+
+	private static final long serialVersionUID = 3706581789209939441L;
+
+	public DbException() {
+		super();
+	}
+
+	public DbException(Throwable t) {
+		super(t);
+	}
+}

briar-core/src/net/sf/briar/api/db/MessageHeader.java

@@ -0,0 +1,35 @@
+package net.sf.briar.api.db;
+
+import net.sf.briar.api.protocol.AuthorId;
+import net.sf.briar.api.protocol.GroupId;
+import net.sf.briar.api.protocol.MessageId;
+
+public interface MessageHeader {
+
+	/** Returns the message's unique identifier. */
+	MessageId getId();
+
+	/**
+	 * Returns the message's parent, or null if this is the first message in a
+	 * thread.
+	 */
+	MessageId getParent();
+
+	/** Returns the group to which the message belongs. */
+	GroupId getGroup();
+
+	/** Returns the message's author. */
+	AuthorId getAuthor();
+
+	/** Returns the message's subject line. */
+	String getSubject();
+
+	/** Returns the timestamp created by the message's author. */
+	long getTimestamp();
+
+	/** Returns true if the message has been read. */
+	boolean getRead();
+
+	/** Returns true if the message has been starred. */
+	boolean getStarred();
+}

briar-core/src/net/sf/briar/api/db/NoSuchContactException.java

@@ -0,0 +1,10 @@
+package net.sf.briar.api.db;
+
+/**
+ * Thrown when a database operation is attempted for a contact that is not in
+ * the database.
+ */
+public class NoSuchContactException extends DbException {
+
+	private static final long serialVersionUID = -7048538231308207386L;
+}

briar-core/src/net/sf/briar/api/db/NoSuchContactTransportException.java

@@ -0,0 +1,10 @@
+package net.sf.briar.api.db;
+
+/**
+ * Thrown when a database operation is attempted for a contact transport that
+ * is not in the database.
+ */
+public class NoSuchContactTransportException extends DbException {
+
+	private static final long serialVersionUID = -6274982612759573100L;
+}

briar-core/src/net/sf/briar/api/db/event/BatchReceivedEvent.java

@@ -0,0 +1,6 @@
+package net.sf.briar.api.db.event;
+
+/** An event that is broadcast when a batch of messages is received. */
+public class BatchReceivedEvent extends DatabaseEvent {
+
+}

briar-core/src/net/sf/briar/api/db/event/ContactAddedEvent.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api.db.event;
+
+import net.sf.briar.api.ContactId;
+
+/** An event that is broadcast when a contact is added. */
+public class ContactAddedEvent extends DatabaseEvent {
+
+	private final ContactId contactId;
+
+	public ContactAddedEvent(ContactId contactId) {
+		this.contactId = contactId;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+}

briar-core/src/net/sf/briar/api/db/event/ContactRemovedEvent.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api.db.event;
+
+import net.sf.briar.api.ContactId;
+
+/** An event that is broadcast when a contact is removed. */
+public class ContactRemovedEvent extends DatabaseEvent {
+
+	private final ContactId contactId;
+
+	public ContactRemovedEvent(ContactId contactId) {
+		this.contactId = contactId;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+}

briar-core/src/net/sf/briar/api/db/event/DatabaseEvent.java

@@ -0,0 +1,6 @@
+package net.sf.briar.api.db.event;
+
+/** An abstract superclass for database events. */
+public abstract class DatabaseEvent {
+
+}

briar-core/src/net/sf/briar/api/db/event/DatabaseListener.java

@@ -0,0 +1,7 @@
+package net.sf.briar.api.db.event;
+
+/** An interface for receiving notifications when database events occur. */
+public interface DatabaseListener {
+
+	void eventOccurred(DatabaseEvent e);
+}

briar-core/src/net/sf/briar/api/db/event/LocalTransportsUpdatedEvent.java

@@ -0,0 +1,9 @@
+package net.sf.briar.api.db.event;
+
+/**
+ * An event that is broadcast when the local transport properties are
+ * updated.
+ */
+public class LocalTransportsUpdatedEvent extends DatabaseEvent {
+
+}

briar-core/src/net/sf/briar/api/db/event/MessagesAddedEvent.java

@@ -0,0 +1,9 @@
+package net.sf.briar.api.db.event;
+
+/**
+ * An event that is broadcast when one or more messages are added to the
+ * database.
+ */
+public class MessagesAddedEvent extends DatabaseEvent {
+
+}

briar-core/src/net/sf/briar/api/db/event/RatingChangedEvent.java

@@ -0,0 +1,23 @@
+package net.sf.briar.api.db.event;
+
+import net.sf.briar.api.Rating;
+import net.sf.briar.api.protocol.AuthorId;
+
+public class RatingChangedEvent extends DatabaseEvent {
+
+	private final AuthorId author;
+	private final Rating rating;
+
+	public RatingChangedEvent(AuthorId author, Rating rating) {
+		this.author = author;
+		this.rating = rating;
+	}
+
+	public AuthorId getAuthor() {
+		return author;
+	}
+
+	public Rating getRating() {
+		return rating;
+	}
+}

briar-core/src/net/sf/briar/api/db/event/RemoteTransportsUpdatedEvent.java

@@ -0,0 +1,27 @@
+package net.sf.briar.api.db.event;
+
+import java.util.Collection;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.protocol.Transport;
+
+/** An event that is broadcast when a contact's transports are updated. */
+public class RemoteTransportsUpdatedEvent extends DatabaseEvent {
+
+	private final ContactId contactId;
+	private final Collection<Transport> transports;
+
+	public RemoteTransportsUpdatedEvent(ContactId contactId,
+			Collection<Transport> transports) {
+		this.contactId = contactId;
+		this.transports = transports;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	public Collection<Transport> getTransports() {
+		return transports;
+	}
+}

briar-core/src/net/sf/briar/api/db/event/SubscriptionsUpdatedEvent.java

@@ -0,0 +1,28 @@
+package net.sf.briar.api.db.event;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import net.sf.briar.api.ContactId;
+
+/**
+ * An event that is broadcast when the set of subscriptions visible to one or
+ * more contacts is updated.
+ */
+public class SubscriptionsUpdatedEvent extends DatabaseEvent {
+
+	private final Collection<ContactId> affectedContacts;
+
+	public SubscriptionsUpdatedEvent() {
+		affectedContacts = Collections.emptyList();
+	}
+
+	public SubscriptionsUpdatedEvent(Collection<ContactId> affectedContacts) {
+		this.affectedContacts = affectedContacts;
+	}
+
+	/** Returns the contacts affected by the update. */
+	public Collection<ContactId> getAffectedContacts() {
+		return affectedContacts;
+	}
+}

briar-core/src/net/sf/briar/api/invitation/InvitationListener.java

@@ -0,0 +1,26 @@
+package net.sf.briar.api.invitation;
+
+/**
+ * An interface for receiving updates about the state of an
+ * {@link InvitationTask}.
+ */
+public interface InvitationListener {
+
+	/** Called if a connection is established and key agreement succeeds. */
+	void connectionSucceeded(int localCode, int remoteCode);
+
+	/** Called if a connection cannot be established. */
+	void connectionFailed();
+
+	/**
+	 * Informs the local peer that the remote peer's confirmation check
+	 * succeeded.
+	 */
+	void remoteConfirmationSucceeded();
+
+	/**
+	 * Informs the local peer that the remote peer's confirmation check did
+	 * not succeed, or the connection was lost during confirmation.
+	 */
+	void remoteConfirmationFailed();
+}

briar-core/src/net/sf/briar/api/invitation/InvitationManager.java

@@ -0,0 +1,22 @@
+package net.sf.briar.api.invitation;
+
+/** Creates and manages tasks for exchanging invitations with remote peers. */
+public interface InvitationManager {
+
+	/** Creates a task using the given invitation codes. */
+	InvitationTask createTask(int localCode, int remoteCode);
+
+	/**
+	 * Returns the previously created task with the given handle, unless the
+	 * task has subsequently removed itself.
+	 */
+	InvitationTask getTask(int handle);
+
+	/** Called by tasks to add themselves to the manager when they start. */
+	void putTask(int handle, InvitationTask task);
+
+	/**
+	 * Called by tasks to remove themselves from the managet when they finish.
+	 */
+	void removeTask(int handle);
+}

briar-core/src/net/sf/briar/api/invitation/InvitationState.java

@@ -0,0 +1,62 @@
+package net.sf.briar.api.invitation;
+
+public class InvitationState {
+
+	private final int localInvitationCode, remoteInvitationCode;
+	private final int localConfirmationCode, remoteConfirmationCode;
+	private final boolean connectionFailed;
+	private final boolean localCompared, remoteCompared;
+	private final boolean localMatched, remoteMatched;
+
+	public InvitationState(int localInvitationCode, int remoteInvitationCode,
+			int localConfirmationCode, int remoteConfirmationCode,
+			boolean connectionFailed, boolean localCompared,
+			boolean remoteCompared, boolean localMatched,
+			boolean remoteMatched) {
+		this.localInvitationCode = localInvitationCode;
+		this.remoteInvitationCode = remoteInvitationCode;
+		this.localConfirmationCode = localConfirmationCode;
+		this.remoteConfirmationCode = remoteConfirmationCode;
+		this.connectionFailed = connectionFailed;
+		this.localCompared = localCompared;
+		this.remoteCompared = remoteCompared;
+		this.localMatched = localMatched;
+		this.remoteMatched = remoteMatched;
+	}
+
+	public int getLocalInvitationCode() {
+		return localInvitationCode;
+	}
+
+	public int getRemoteInvitationCode() {
+		return remoteInvitationCode;
+	}
+
+	public int getLocalConfirmationCode() {
+		return localConfirmationCode;
+	}
+
+	public int getRemoteConfirmationCode() {
+		return remoteConfirmationCode;
+	}
+
+	public boolean getConnectionFailed() {
+		return connectionFailed;
+	}
+
+	public boolean getLocalCompared() {
+		return localCompared;
+	}
+
+	public boolean getRemoteCompared() {
+		return remoteCompared;
+	}
+
+	public boolean getLocalMatched() {
+		return localMatched;
+	}
+
+	public boolean getRemoteMatched() {
+		return remoteMatched;
+	}
+}

briar-core/src/net/sf/briar/api/invitation/InvitationTask.java

@@ -0,0 +1,32 @@
+package net.sf.briar.api.invitation;
+
+/** A task for exchanging invitations with a remote peer. */
+public interface InvitationTask {
+
+	/** Returns the task's unique handle. */
+	int getHandle();
+
+	/**
+	 * Adds a listener to be informed of state changes and returns the
+	 * task's current state.
+	 */
+	InvitationState addListener(InvitationListener l);
+
+	/** Removes the given listener. */
+	void removeListener(InvitationListener l);
+
+	/** Asynchronously starts the connection process. */
+	void connect();
+
+	/**
+	 * Asynchronously informs the remote peer that the local peer's
+	 * confirmation codes matched.
+	 */
+	void localConfirmationSucceeded();
+
+	/**
+	 * Asynchronously informs the remote peer that the local peer's
+	 * confirmation codes did not match.
+	 */
+	void localConfirmationFailed();
+}

briar-core/src/net/sf/briar/api/lifecycle/ShutdownManager.java

@@ -0,0 +1,16 @@
+package net.sf.briar.api.lifecycle;
+
+public interface ShutdownManager {
+
+	/**
+	 * Registers a hook to be run when the JVM shuts down and returns a handle
+	 * that can be used to remove the hook.
+	 */
+	int addShutdownHook(Runnable hook);
+
+	/**
+	 * Removes the shutdown hook identified by the given handle and returns
+	 * true if the hook was removed.
+	 */
+	boolean removeShutdownHook(int handle);
+}

briar-core/src/net/sf/briar/api/plugins/InvitationConstants.java

@@ -0,0 +1,16 @@
+package net.sf.briar.api.plugins;
+
+public interface InvitationConstants {
+
+	long CONNECTION_TIMEOUT = 15 * 1000; // Milliseconds
+
+	long CONFIRMATION_TIMEOUT = 60 * 1000; // Milliseconds
+
+	int CODE_BITS = 19; // Codes must fit into six decimal digits
+
+	int MAX_CODE = (1 << CODE_BITS) - 1; // 524287
+
+	int HASH_LENGTH = 48; // Bytes
+
+	int MAX_PUBLIC_KEY_LENGTH = 120; // Bytes
+}

briar-core/src/net/sf/briar/api/plugins/Plugin.java

@@ -0,0 +1,41 @@
+package net.sf.briar.api.plugins;
+
+import java.io.IOException;
+import java.util.Collection;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.protocol.TransportId;
+
+public interface Plugin {
+
+	/** Returns the plugin's transport identifier. */
+	TransportId getId();
+
+	/** Returns a label for looking up the plugin's translated name. */
+	String getName();
+
+	/** Starts the plugin and returns true if it started successfully. */
+	boolean start() throws IOException;
+
+	/** Stops the plugin. */
+	void stop() throws IOException;
+
+	/**
+	 * Returns true if the plugin's {@link Plugin#poll(Collection)} method
+	 * should be called periodically to attempt to establish connections.
+	 */
+	boolean shouldPoll();
+
+	/**
+	 * Returns the desired interval in milliseconds between calls to the
+	 * plugin's {@link Plugin#poll(Collection)} method.
+	 */
+	long getPollingInterval();
+
+	/**
+	 * Attempts to establish connections to contacts, passing any created
+	 * connections to the callback. To avoid creating redundant connections,
+	 * the plugin may exclude the given contacts from polling.
+	 */
+	void poll(Collection<ContactId> connected);
+}

briar-core/src/net/sf/briar/api/plugins/PluginCallback.java

@@ -0,0 +1,52 @@
+package net.sf.briar.api.plugins;
+
+import java.util.Map;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportConfig;
+import net.sf.briar.api.TransportProperties;
+
+/**
+ * An interface through which a transport plugin interacts with the rest of
+ * the application.
+ */
+public interface PluginCallback {
+
+	/** Returns the plugin's configuration. */
+	TransportConfig getConfig();
+
+	/** Returns the plugin's local transport properties. */
+	TransportProperties getLocalProperties();
+
+	/** Returns the plugin's remote transport properties. */
+	Map<ContactId, TransportProperties> getRemoteProperties();
+
+	/** Merges the given configuration with the plugin's configuration. */
+	void mergeConfig(TransportConfig c);
+
+	/**
+	 * Merges the given properties with the plugin's local transport properties.
+	 */
+	void mergeLocalProperties(TransportProperties p);
+
+	/**
+	 * Presents the user with a choice among two or more named options and
+	 * returns the user's response. The message may consist of a translatable
+	 * format string and arguments.
+	 * @return an index into the array of options indicating the user's choice,
+	 * or -1 if the user cancelled the choice.
+	 */
+	int showChoice(String[] options, String... message);
+
+	/**
+	 * Asks the user to confirm an action and returns the user's response. The
+	 * message may consist of a translatable format string and arguments.
+	 */
+	boolean showConfirmationMessage(String... message);
+
+	/**
+	 * Shows a message to the user. The message may consist of a translatable
+	 * format string and arguments.
+	 */
+	void showMessage(String... message);
+}

briar-core/src/net/sf/briar/api/plugins/PluginExecutor.java

@@ -0,0 +1,15 @@
+package net.sf.briar.api.plugins;
+
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import com.google.inject.BindingAnnotation;
+
+/** Annotation for injecting the executor used by transport plugins. */
+@BindingAnnotation
+@Target({ PARAMETER })
+@Retention(RUNTIME)
+public @interface PluginExecutor {}

briar-core/src/net/sf/briar/api/plugins/PluginManager.java

@@ -0,0 +1,28 @@
+package net.sf.briar.api.plugins;
+
+import java.util.Collection;
+
+import net.sf.briar.api.plugins.duplex.DuplexPlugin;
+import android.content.Context;
+
+/**
+ * Responsible for starting transport plugins at startup, stopping them at
+ * shutdown, and providing access to plugins for exchanging invitations.
+ */
+public interface PluginManager {
+
+	/**
+	 * Starts the plugins and returns the number of plugins successfully
+	 * started. This method must not be called until the database has been
+	 * opened. The appContext argument is null on non-Android platforms.
+	 */
+	int start(Context appContext);
+
+	/**
+	 * Stops the plugins and returns the number of plugins successfully stopped.
+	 */
+	int stop();
+
+	/** Returns any duplex plugins that support invitations. */
+	Collection<DuplexPlugin> getInvitationPlugins();
+}

briar-core/src/net/sf/briar/api/plugins/duplex/DuplexPlugin.java

@@ -0,0 +1,31 @@
+package net.sf.briar.api.plugins.duplex;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.crypto.PseudoRandom;
+import net.sf.briar.api.plugins.Plugin;
+
+/** An interface for transport plugins that support duplex communication. */
+public interface DuplexPlugin extends Plugin {
+
+	/**
+	 * Attempts to create and return a connection to the given contact using
+	 * the current transport and configuration properties. Returns null if a
+	 * connection could not be created.
+	 */
+	DuplexTransportConnection createConnection(ContactId c);
+
+	/** Returns true if the plugin supports exchanging invitations. */
+	boolean supportsInvitations();
+
+	/**
+	 * Starts the invitation process from the inviter's side. Returns null if
+	 * no connection can be established within the given timeout.
+	 */
+	DuplexTransportConnection sendInvitation(PseudoRandom r, long timeout);
+
+	/**
+	 * Starts the invitation process from the invitee's side. Returns null if
+	 * no connection can be established within the given timeout.
+	 */
+	DuplexTransportConnection acceptInvitation(PseudoRandom r, long timeout);
+}

briar-core/src/net/sf/briar/api/plugins/duplex/DuplexPluginCallback.java

@@ -0,0 +1,14 @@
+package net.sf.briar.api.plugins.duplex;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.plugins.PluginCallback;
+
+/**
+ * An interface for handling connections created by a duplex transport plugin.
+ */
+public interface DuplexPluginCallback extends PluginCallback {
+
+	void incomingConnectionCreated(DuplexTransportConnection d);
+
+	void outgoingConnectionCreated(ContactId c, DuplexTransportConnection d);
+}

briar-core/src/net/sf/briar/api/plugins/duplex/DuplexPluginFactory.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api.plugins.duplex;
+
+import java.util.concurrent.Executor;
+
+import net.sf.briar.api.android.AndroidExecutor;
+import net.sf.briar.api.lifecycle.ShutdownManager;
+import net.sf.briar.api.protocol.TransportId;
+import android.content.Context;
+
+public interface DuplexPluginFactory {
+
+	TransportId getId();
+
+	DuplexPlugin createPlugin(Executor pluginExecutor,
+			AndroidExecutor androidExecutor, Context appContext,
+			ShutdownManager shutdownManager, DuplexPluginCallback callback);
+}

briar-core/src/net/sf/briar/api/plugins/duplex/DuplexTransportConnection.java

@@ -0,0 +1,32 @@
+package net.sf.briar.api.plugins.duplex;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * An interface for reading and writing data over a duplex transport. The
+ * connection is not responsible for encrypting/decrypting or authenticating
+ * the data.
+ */
+public interface DuplexTransportConnection {
+
+	/** Returns an input stream for reading from the connection. */
+	InputStream getInputStream() throws IOException;
+
+	/** Returns an output stream for writing to the connection. */
+	OutputStream getOutputStream() throws IOException;
+
+	/**
+	 * Returns true if the output stream should be flushed after each packet.
+	 */
+	boolean shouldFlush();
+
+	/**
+	 * Closes the connection and disposes of any associated resources. The
+	 * first argument indicates whether the connection is being closed because
+	 * of an exception and the second argument indicates whether the connection
+	 * was recognised, which may affect how resources are disposed of.
+	 */
+	void dispose(boolean exception, boolean recognised) throws IOException;
+}

briar-core/src/net/sf/briar/api/plugins/simplex/SimplexPlugin.java

@@ -0,0 +1,22 @@
+package net.sf.briar.api.plugins.simplex;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.plugins.Plugin;
+
+/** An interface for transport plugins that support simplex communication. */
+public interface SimplexPlugin extends Plugin {
+
+	/**
+	 * Attempts to create and return a reader for the given contact using the
+	 * current transport and configuration properties. Returns null if a reader
+	 * could not be created.
+	 */
+	SimplexTransportReader createReader(ContactId c);
+
+	/**
+	 * Attempts to create and return a writer for the given contact using the
+	 * current transport and configuration properties. Returns null if a writer
+	 * could not be created.
+	 */
+	SimplexTransportWriter createWriter(ContactId c);
+}

briar-core/src/net/sf/briar/api/plugins/simplex/SimplexPluginCallback.java

@@ -0,0 +1,15 @@
+package net.sf.briar.api.plugins.simplex;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.plugins.PluginCallback;
+
+/**
+ * An interface for handling readers and writers created by a simplex transport
+ * plugin.
+ */
+public interface SimplexPluginCallback extends PluginCallback {
+
+	void readerCreated(SimplexTransportReader r);
+
+	void writerCreated(ContactId c, SimplexTransportWriter w);
+}

briar-core/src/net/sf/briar/api/plugins/simplex/SimplexPluginFactory.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api.plugins.simplex;
+
+import java.util.concurrent.Executor;
+
+import net.sf.briar.api.android.AndroidExecutor;
+import net.sf.briar.api.lifecycle.ShutdownManager;
+import net.sf.briar.api.protocol.TransportId;
+import android.content.Context;
+
+public interface SimplexPluginFactory {
+
+	TransportId getId();
+
+	SimplexPlugin createPlugin(Executor pluginExecutor,
+			AndroidExecutor androidExecutor, Context appContext,
+			ShutdownManager shutdownManager, SimplexPluginCallback callback);
+}

briar-core/src/net/sf/briar/api/plugins/simplex/SimplexTransportReader.java

@@ -0,0 +1,22 @@
+package net.sf.briar.api.plugins.simplex;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * An interface for reading data from a simplex transport. The reader is not
+ * responsible for decrypting or authenticating the data before returning it.
+ */
+public interface SimplexTransportReader {
+
+	/** Returns an input stream for reading from the transport. */
+	InputStream getInputStream() throws IOException;
+
+	/**
+	 * Closes the reader and disposes of any associated resources. The first
+	 * argument indicates whether the reader is being closed because of an
+	 * exception and the second argument indicates whether the connection was
+	 * recognised, which may affect how resources are disposed of.
+	 */
+	void dispose(boolean exception, boolean recognised) throws IOException;
+}

briar-core/src/net/sf/briar/api/plugins/simplex/SimplexTransportWriter.java

@@ -0,0 +1,29 @@
+package net.sf.briar.api.plugins.simplex;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * An interface for writing data to a simplex transport. The writer is not
+ * responsible for authenticating or encrypting the data before writing it.
+ */
+public interface SimplexTransportWriter {
+
+	/** Returns the capacity of the transport in bytes. */
+	long getCapacity();
+
+	/** Returns an output stream for writing to the transport. */
+	OutputStream getOutputStream() throws IOException;
+
+	/**
+	 * Returns true if the output stream should be flushed after each packet.
+	 */
+	boolean shouldFlush();
+
+	/**
+	 * Closes the writer and disposes of any associated resources. The
+	 * argument indicates whether the writer is being closed because of an
+	 * exception, which may affect how resources are disposed of.
+	 */
+	void dispose(boolean exception) throws IOException;
+}

briar-core/src/net/sf/briar/api/protocol/Ack.java

@@ -0,0 +1,10 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Collection;
+
+/** A packet acknowledging receipt of one or more batches. */
+public interface Ack {
+
+	/** Returns the IDs of the acknowledged batches. */
+	Collection<BatchId> getBatchIds();
+}

briar-core/src/net/sf/briar/api/protocol/Author.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api.protocol;
+
+/** A pseudonymous author of messages. */
+public interface Author {
+
+	/** Returns the author's unique identifier. */
+	AuthorId getId();
+
+	/** Returns the author's name. */
+	String getName();
+
+	/**
+	 * Returns the public key that is used to verify messages signed by the
+	 * author.
+	 */
+	byte[] getPublicKey();
+}

briar-core/src/net/sf/briar/api/protocol/AuthorFactory.java

@@ -0,0 +1,10 @@
+package net.sf.briar.api.protocol;
+
+import java.io.IOException;
+
+public interface AuthorFactory {
+
+	Author createAuthor(String name, byte[] publicKey) throws IOException;
+
+	Author createAuthor(AuthorId id, String name, byte[] publicKey);
+}

briar-core/src/net/sf/briar/api/protocol/AuthorId.java

@@ -0,0 +1,18 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Arrays;
+
+/** Type-safe wrapper for a byte array that uniquely identifies an author. */
+public class AuthorId extends UniqueId {
+
+	public AuthorId(byte[] id) {
+		super(id);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if(o instanceof AuthorId)
+			return Arrays.equals(id, ((AuthorId) o).id);
+		return false;
+	}
+}

briar-core/src/net/sf/briar/api/protocol/Batch.java

@@ -0,0 +1,13 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Collection;
+
+/** An incoming packet containing messages. */
+public interface Batch {
+
+	/** Returns the batch's unique identifier. */
+	BatchId getId();
+
+	/** Returns the messages contained in the batch. */
+	Collection<Message> getMessages();
+}

briar-core/src/net/sf/briar/api/protocol/BatchId.java

@@ -0,0 +1,21 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Arrays;
+
+/**
+ * Type-safe wrapper for a byte array that uniquely identifies a batch of
+ * messages.
+ */
+public class BatchId extends UniqueId {
+
+	public BatchId(byte[] id) {
+		super(id);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if(o instanceof BatchId)
+			return Arrays.equals(id, ((BatchId) o).id);
+		return false;
+	}
+}

briar-core/src/net/sf/briar/api/protocol/Group.java

@@ -0,0 +1,17 @@
+package net.sf.briar.api.protocol;
+
+/** A group to which users may subscribe. */
+public interface Group {
+
+	/** Returns the group's unique identifier. */
+	GroupId getId();
+
+	/** Returns the group's name. */
+	String getName();
+
+	/**
+	 * If the group is restricted, returns the public key that is used to
+	 * authorise all messages sent to the group. Otherwise returns null.
+	 */
+	byte[] getPublicKey();
+}

briar-core/src/net/sf/briar/api/protocol/GroupFactory.java

@@ -0,0 +1,10 @@
+package net.sf.briar.api.protocol;
+
+import java.io.IOException;
+
+public interface GroupFactory {
+
+	Group createGroup(String name, byte[] publicKey) throws IOException;
+
+	Group createGroup(GroupId id, String name, byte[] publicKey);
+}

briar-core/src/net/sf/briar/api/protocol/GroupId.java

@@ -0,0 +1,21 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Arrays;
+
+/**
+ * Type-safe wrapper for a byte array that uniquely identifies a group to which
+ * users may subscribe.
+ */
+public class GroupId extends UniqueId {
+
+	public GroupId(byte[] id) {
+		super(id);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if(o instanceof GroupId)
+			return Arrays.equals(id, ((GroupId) o).id);
+		return false;
+	}
+}

briar-core/src/net/sf/briar/api/protocol/Message.java

@@ -0,0 +1,34 @@
+package net.sf.briar.api.protocol;
+
+public interface Message {
+
+	/** Returns the message's unique identifier. */
+	MessageId getId();
+
+	/**
+	 * Returns the message's parent, or null if this is the first message in a
+	 * thread.
+	 */
+	MessageId getParent();
+
+	/** Returns the group to which the message belongs. */
+	GroupId getGroup();
+
+	/** Returns the message's author. */
+	AuthorId getAuthor();
+
+	/** Returns the message's subject line. */
+	String getSubject();
+
+	/** Returns the timestamp created by the message's author. */
+	long getTimestamp();
+
+	/** Returns the serialised message. */
+	byte[] getSerialised();
+
+	/** Returns the offset of the message body within the serialised message. */
+	int getBodyStart();
+
+	/** Returns the length of the message body in bytes. */
+	int getBodyLength();
+}

briar-core/src/net/sf/briar/api/protocol/MessageFactory.java

@@ -0,0 +1,31 @@
+package net.sf.briar.api.protocol;
+
+import java.io.IOException;
+import java.security.GeneralSecurityException;
+import java.security.PrivateKey;
+
+public interface MessageFactory {
+
+	/** Creates a private message. */
+	Message createMessage(MessageId parent, String subject, byte[] body)
+	throws IOException, GeneralSecurityException;
+
+	/** Creates an anonymous message to an unrestricted group. */
+	Message createMessage(MessageId parent, Group group, String subject,
+			byte[] body) throws IOException, GeneralSecurityException;
+
+	/** Creates an anonymous message to a restricted group. */
+	Message createMessage(MessageId parent, Group group, PrivateKey groupKey,
+			String subject, byte[] body) throws IOException,
+			GeneralSecurityException;
+
+	/** Creates a pseudonymous message to an unrestricted group. */
+	Message createMessage(MessageId parent, Group group, Author author,
+			PrivateKey authorKey, String subject, byte[] body)
+	throws IOException, GeneralSecurityException;
+
+	/** Creates a pseudonymous message to a restricted group. */
+	Message createMessage(MessageId parent, Group group, PrivateKey groupKey,
+			Author author, PrivateKey authorKey, String subject, byte[] body)
+	throws IOException, GeneralSecurityException;
+}

briar-core/src/net/sf/briar/api/protocol/MessageId.java

@@ -0,0 +1,18 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Arrays;
+
+/** Type-safe wrapper for a byte array that uniquely identifies a message. */
+public class MessageId extends UniqueId {
+
+	public MessageId(byte[] id) {
+		super(id);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if(o instanceof MessageId)
+			return Arrays.equals(id, ((MessageId) o).id);
+		return false;
+	}
+}

briar-core/src/net/sf/briar/api/protocol/Offer.java

@@ -0,0 +1,10 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Collection;
+
+/** A packet offering the recipient some messages. */
+public interface Offer {
+
+	/** Returns the message IDs contained in the offer. */
+	Collection<MessageId> getMessageIds();
+}

briar-core/src/net/sf/briar/api/protocol/PacketFactory.java

@@ -0,0 +1,22 @@
+package net.sf.briar.api.protocol;
+
+import java.util.BitSet;
+import java.util.Collection;
+import java.util.Map;
+
+public interface PacketFactory {
+
+	Ack createAck(Collection<BatchId> acked);
+
+	RawBatch createBatch(Collection<byte[]> messages);
+
+	Offer createOffer(Collection<MessageId> offered);
+
+	Request createRequest(BitSet requested, int length);
+
+	SubscriptionUpdate createSubscriptionUpdate(Map<GroupId, GroupId> holes,
+			Map<Group, Long> subs, long expiry, long timestamp);
+
+	TransportUpdate createTransportUpdate(Collection<Transport> transports,
+			long timestamp);
+}

briar-core/src/net/sf/briar/api/protocol/ProtocolConstants.java

@@ -0,0 +1,47 @@
+package net.sf.briar.api.protocol;
+
+import static net.sf.briar.api.transport.TransportConstants.MIN_CONNECTION_LENGTH;
+
+public interface ProtocolConstants {
+
+	/**
+	 * The maximum length of a serialised packet in bytes. To allow for future
+	 * changes in the protocol, this is smaller than the minimum connection
+	 * length minus the maximum encryption and authentication overhead.
+	 */
+	int MAX_PACKET_LENGTH = MIN_CONNECTION_LENGTH / 2;
+
+	/** The maximum number of transports a node may support. */
+	int MAX_TRANSPORTS = 25;
+
+	/** The maximum number of properties per transport. */
+	int MAX_PROPERTIES_PER_TRANSPORT = 100;
+
+	/** The maximum length of a property's key or value in UTF-8 bytes. */
+	int MAX_PROPERTY_LENGTH = 100;
+
+	/** The maximum length of a group's name in UTF-8 bytes. */
+	int MAX_GROUP_NAME_LENGTH = 50;
+
+	/** The maximum length of a public key in bytes. */
+	int MAX_PUBLIC_KEY_LENGTH = 120;
+
+	/** The maximum length of an author's name in UTF-8 bytes. */
+	int MAX_AUTHOR_NAME_LENGTH = 50;
+
+	/**
+	 * The maximum length of a message body in bytes. To allow for future
+	 * changes in the protocol, this is smaller than the maximum packet length
+	 * even when all the message's other fields have their maximum lengths.
+	 */
+	int MAX_BODY_LENGTH = MAX_PACKET_LENGTH - 1024;
+
+	/** The maximum length of a message's subject line in UTF-8 bytes. */
+	int MAX_SUBJECT_LENGTH = 100;
+
+	/** The maximum length of a signature in bytes. */
+	int MAX_SIGNATURE_LENGTH = 120;
+
+	/** The length of a message's random salt in bytes. */
+	int SALT_LENGTH = 8;
+}

briar-core/src/net/sf/briar/api/protocol/ProtocolReader.java

@@ -0,0 +1,26 @@
+package net.sf.briar.api.protocol;
+
+import java.io.IOException;
+
+public interface ProtocolReader {
+
+	boolean eof() throws IOException;
+
+	boolean hasAck() throws IOException;
+	Ack readAck() throws IOException;
+
+	boolean hasBatch() throws IOException;
+	UnverifiedBatch readBatch() throws IOException;
+
+	boolean hasOffer() throws IOException;
+	Offer readOffer() throws IOException;
+
+	boolean hasRequest() throws IOException;
+	Request readRequest() throws IOException;
+
+	boolean hasSubscriptionUpdate() throws IOException;
+	SubscriptionUpdate readSubscriptionUpdate() throws IOException;
+
+	boolean hasTransportUpdate() throws IOException;
+	TransportUpdate readTransportUpdate() throws IOException;
+}

briar-core/src/net/sf/briar/api/protocol/ProtocolReaderFactory.java

@@ -0,0 +1,8 @@
+package net.sf.briar.api.protocol;
+
+import java.io.InputStream;
+
+public interface ProtocolReaderFactory {
+
+	ProtocolReader createProtocolReader(InputStream in);
+}

briar-core/src/net/sf/briar/api/protocol/ProtocolWriter.java

@@ -0,0 +1,28 @@
+package net.sf.briar.api.protocol;
+
+import java.io.IOException;
+
+public interface ProtocolWriter {
+
+	int getMaxBatchesForAck(long capacity);
+
+	int getMaxMessagesForOffer(long capacity);
+
+	int getMessageCapacityForBatch(long capacity);
+
+	void writeAck(Ack a) throws IOException;
+
+	void writeBatch(RawBatch b) throws IOException;
+
+	void writeOffer(Offer o) throws IOException;
+
+	void writeRequest(Request r) throws IOException;
+
+	void writeSubscriptionUpdate(SubscriptionUpdate s) throws IOException;
+
+	void writeTransportUpdate(TransportUpdate t) throws IOException;
+
+	void flush() throws IOException;
+
+	void close() throws IOException;
+}

briar-core/src/net/sf/briar/api/protocol/ProtocolWriterFactory.java

@@ -0,0 +1,8 @@
+package net.sf.briar.api.protocol;
+
+import java.io.OutputStream;
+
+public interface ProtocolWriterFactory {
+
+	ProtocolWriter createProtocolWriter(OutputStream out, boolean flush);
+}

briar-core/src/net/sf/briar/api/protocol/RawBatch.java

@@ -0,0 +1,13 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Collection;
+
+/** An outgoing packet containing messages. */
+public interface RawBatch {
+
+	/** Returns the batch's unique identifier. */
+	BatchId getId();
+
+	/** Returns the serialised messages contained in the batch. */
+	Collection<byte[]> getMessages();
+}

briar-core/src/net/sf/briar/api/protocol/Request.java

@@ -0,0 +1,16 @@
+package net.sf.briar.api.protocol;
+
+import java.util.BitSet;
+
+/** A packet requesting some or all of the messages from an offer. */
+public interface Request {
+
+	/**
+	 * Returns a sequence of bits corresponding to the sequence of messages in
+	 * the offer, where the i^th bit is set if the i^th message should be sent.
+	 */
+	BitSet getBitmap();
+
+	/** Returns the length of the bitmap in bits. */
+	int getLength();
+}

briar-core/src/net/sf/briar/api/protocol/SubscriptionUpdate.java

@@ -0,0 +1,25 @@
+package net.sf.briar.api.protocol;
+
+import java.util.Map;
+
+/** A packet updating the sender's subscriptions. */
+public interface SubscriptionUpdate {
+
+	/** Returns the holes contained in the update. */
+	Map<GroupId, GroupId> getHoles();
+
+	/** Returns the subscriptions contained in the update. */
+	Map<Group, Long> getSubscriptions();
+
+	/**
+	 * Returns the expiry time of the contact's database. Messages that are
+	 * older than the expiry time must not be sent to the contact.
+	 */
+	long getExpiryTime();
+
+	/**
+	 * Returns the update's timestamp. Updates that are older than the newest
+	 * update received from the same contact must be ignored.
+	 */
+	long getTimestamp();
+}