diff --git a/api/net/sf/briar/api/db/DatabaseComponent.java b/api/net/sf/briar/api/db/DatabaseComponent.java
index 8be61c5cd0d83c18204995770e471e3397827d22..9c12e40e5ddd1719e54fa6c4db1771942390dd09 100644
--- a/api/net/sf/briar/api/db/DatabaseComponent.java
+++ b/api/net/sf/briar/api/db/DatabaseComponent.java
@@ -26,25 +26,22 @@ public interface DatabaseComponent {
static final int CLEANER_SLEEP_MS = 1000; // 1 sec
static final int RETRANSMIT_THRESHOLD = 3;
- /** Waits for any open transactions to finish and closes the database. */
- void close() throws DbException;
-
/** Adds a locally generated message to the database. */
void addLocallyGeneratedMessage(Message m) throws DbException;
/** Adds a new neighbour to the database. */
void addNeighbour(NeighbourId n) throws DbException;
+ /** Waits for any open transactions to finish and closes the database. */
+ void close() throws DbException;
+
/** Generates a bundle of messages for the given neighbour. */
void generateBundle(NeighbourId n, Bundle b) throws DbException;
- /**
- * Returns the rating assigned to the given author, which may be
- * Rating.UNRATED if no rating has been assigned.
- */
+ /** Returns the user's rating for the given author. */
Rating getRating(AuthorId a) throws DbException;
- /** Returns the set of groups to which we subscribe. */
+ /** Returns the set of groups to which the user subscribes. */
Set<GroupId> getSubscriptions() throws DbException;
/**
@@ -53,7 +50,7 @@ public interface DatabaseComponent {
*/
void receiveBundle(NeighbourId n, Bundle b) throws DbException;
- /** Stores a rating for the given author. */
+ /** Records the user's rating for the given author. */
void setRating(AuthorId a, Rating r) throws DbException;
/** Subscribes to the given group. */
@@ -61,7 +58,7 @@ public interface DatabaseComponent {
/**
* Unsubscribes from the given group. Any messages belonging to the group
- * will be deleted from the database.
+ * are deleted from the database.
*/
void unsubscribe(GroupId g) throws DbException;
}
diff --git a/components/net/sf/briar/db/Database.java b/components/net/sf/briar/db/Database.java
index 29b048fd8927a9c516f855e0456e34752d7283b4..a50518218fa6426f45d98e90da269a538b9533e5 100644
--- a/components/net/sf/briar/db/Database.java
+++ b/components/net/sf/briar/db/Database.java
@@ -13,102 +13,227 @@ import net.sf.briar.api.protocol.GroupId;
import net.sf.briar.api.protocol.Message;
import net.sf.briar.api.protocol.MessageId;
+/**
+ * A low-level interface to the database that is managed by a
+ * DatabaseComponent. Most operations take a transaction argument, which is
+ * obtained by calling startTransaction(). Every transaction must be
+ * terminated by calling either abortTransaction() or commitTransaction(),
+ * even if an exception is thrown.
+ */
interface Database<T> {
+ /**
+ * Opens the database.
+ * @param resume True to reopen an existing database, false to create a
+ * new one.
+ */
void open(boolean resume) throws DbException;
+ /** Waits for all open transactions to finish and closes the database. */
void close() throws DbException;
+ /** Starts a new transaction and returns an object representing it. */
T startTransaction(String name) throws DbException;
+ /**
+ * Aborts the given transaction - no changes made during the transaction
+ * will be applied to the database.
+ */
void abortTransaction(T txn);
+ /**
+ * Commits the given transaction - all changes made during the transaction
+ * will be applied to the database.
+ */
void commitTransaction(T txn) throws DbException;
- // Locking: neighbours write
+ /**
+ * Records a received batch as needing to be acknowledged.
+ * Locking: neighbours write.
+ */
void addBatchToAck(T txn, NeighbourId n, BatchId b) throws DbException;
- // Locking: neighbours write
+ /**
+ * Returns false if the given message is already in the database. Otherwise
+ * stores the message and returns true.
+ * Locking: messages write.
+ */
+ boolean addMessage(T txn, Message m) throws DbException;
+
+ /**
+ * Adds a new neighbour to the database.
+ * Locking: neighbours write.
+ */
void addNeighbour(T txn, NeighbourId n) throws DbException;
- // Locking: neighbours write, messages read
+ /**
+ * Records a sent batch as needing to be acknowledged.
+ * Locking: neighbours write, messages read.
+ */
void addOutstandingBatch(T txn, NeighbourId n, BatchId b, Set<MessageId> sent) throws DbException;
- // Locking: neighbours write, messages read
+ /**
+ * Records a received bundle. This should be called after processing the
+ * bundle's contents, and may result in outstanding messages becoming
+ * eligible for retransmittion.
+ * Locking: neighbours write, messages read.
+ */
Set<BatchId> addReceivedBundle(T txn, NeighbourId n, BundleId b) throws DbException;
- // Locking: subscriptions write
+ /**
+ * Subscribes to the given group.
+ * Locking: subscriptions write.
+ */
void addSubscription(T txn, GroupId g) throws DbException;
- // Locking: neighbours write
+ /**
+ * Records a neighbour's subscription to a group.
+ * Locking: neighbours write.
+ */
void addSubscription(T txn, NeighbourId n, GroupId g) throws DbException;
- // Locking: neighbours write
+ /**
+ * Removes all recorded subscriptions for the given neighbour.
+ * Locking: neighbours write.
+ */
void clearSubscriptions(T txn, NeighbourId n) throws DbException;
- // Locking: messages read
+ /**
+ * Returns true iff the database contains the given message.
+ * Locking: messages read.
+ */
boolean containsMessage(T txn, MessageId m) throws DbException;
- // Locking: subscriptions read
+ /**
+ * Returns true iff the user is subscribed to the given group.
+ * Locking: subscriptions read.
+ */
boolean containsSubscription(T txn, GroupId g) throws DbException;
- // Locking: messages read
+ /**
+ * Returns the amount of free storage space available to the database, in
+ * bytes. This is based on the minimum of the space available on the device
+ * where the database is stored and the database's configured size.
+ * Locking: messages read.
+ */
long getFreeSpace() throws DbException;
- // Locking: messages read
+ /**
+ * Returns the message identified by the given ID.
+ * Locking: messages read.
+ */
Message getMessage(T txn, MessageId m) throws DbException;
- // Locking: messages read
+ /**
+ * Returns the IDs of all messages signed by the given author.
+ * Locking: messages read.
+ */
Iterable<MessageId> getMessagesByAuthor(T txn, AuthorId a) throws DbException;
- // Locking: messages read
+ /**
+ * Returns the IDs of all children of the message identified by the given
+ * ID that are present in the database.
+ * Locking: messages read.
+ */
Iterable<MessageId> getMessagesByParent(T txn, MessageId m) throws DbException;
- // Locking: neighbours read
+ /**
+ * Returns the IDs of all neighbours
+ * Locking: neighbours read.
+ */
Set<NeighbourId> getNeighbours(T txn) throws DbException;
- // Locking: messages read
+ /**
+ * Returns the IDs of the oldest messages in the database, with a total
+ * size less than or equal to the given size.
+ * Locking: messages read.
+ */
Iterable<MessageId> getOldMessages(T txn, long size) throws DbException;
- // Locking: messages read
+ /**
+ * Returns the parent of the given message.
+ * Locking: messages read.
+ */
MessageId getParent(T txn, MessageId m) throws DbException;
- // Locking: ratings read
+ /**
+ * Returns the user's rating for the given author.
+ * Locking: ratings read.
+ */
Rating getRating(T txn, AuthorId a) throws DbException;
- // Locking: messages read
+ /**
+ * Returns the sendability score of the given message. Messages with
+ * sendability scores greater than zero are eligible to be sent to
+ * neighbours.
+ * Locking: messages read.
+ */
int getSendability(T txn, MessageId m) throws DbException;
- // Locking: neighbours read, messages read
+ /**
+ * Returns the IDs of some messages that are eligible to be sent to the
+ * given neighbour, with a total size less than or equal to the given size.
+ * Locking: neighbours read, messages read.
+ */
Iterable<MessageId> getSendableMessages(T txn, NeighbourId n, long capacity) throws DbException;
- // Locking: subscriptions read
+ /**
+ * Returns the groups to which the user subscribes.
+ * Locking: subscriptions read.
+ */
Set<GroupId> getSubscriptions(T txn) throws DbException;
- // Locking: messages write
- boolean addMessage(T txn, Message m) throws DbException;
-
- // Locking: ratings write
- Rating setRating(T txn, AuthorId a, Rating r) throws DbException;
-
- // Locking: messages write
- void setSendability(T txn, MessageId m, int sendability) throws DbException;
-
- // Locking: neighbours read, n write
+ /**
+ * Removes and returns the IDs of any batches received from the given
+ * neighbour that need to be acknowledged.
+ * Locking: neighbours write.
+ */
Set<BatchId> removeBatchesToAck(T txn, NeighbourId n) throws DbException;
- // Locking: neighbours write, messages read
+ /**
+ * Removes an outstanding batch that is considered to have been lost. Any
+ * messages in the batch that are still considered outstanding
+ * (Status.SENT) with respect to the given neighbour are now considered
+ * unsent (Status.NEW).
+ * Locking: neighbours write, messages read.
+ */
void removeLostBatch(T txn, NeighbourId n, BatchId b) throws DbException;
- // Locking: neighbours write, messages write
+ /**
+ * Removes a message from the database.
+ * Locking: neighbours write, messages write.
+ */
void removeMessage(T txn, MessageId m) throws DbException;
- // Locking: neighbours write
+ /**
+ * Removes an outstanding batch that has been acknowledged. The status of
+ * the acknowledged messages is not updated.
+ * Locking: neighbours write.
+ */
Set<MessageId> removeOutstandingBatch(T txn, NeighbourId n, BatchId b) throws DbException;
- // Locking: subscriptions write, neighbours write, messages write
+ /**
+ * Unsubscribes from the given group. Any messages belonging to the group
+ * are deleted from the database.
+ * Locking: subscriptions write, neighbours write, messages write.
+ */
void removeSubscription(T txn, GroupId g) throws DbException;
- // Locking: neighbours write, messages read
+ /**
+ * Records the user's rating for the given author.
+ * Locking: ratings write.
+ */
+ Rating setRating(T txn, AuthorId a, Rating r) throws DbException;
+
+ /**
+ * Records the sendability score of the given message.
+ * Locking: messages write.
+ */
+ void setSendability(T txn, MessageId m, int sendability) throws DbException;
+
+ /**
+ * Sets the status of the given message with respect to the given neighbour.
+ * Locking: neighbours write, messages read
+ */
void setStatus(T txn, NeighbourId n, MessageId m, Status s) throws DbException;
}