Merge branch '2077-anything-to-send' into '1802-sync-via-removable-storage'

Add DB method for checking whether there's anything to send

See merge request briar/briar!1485

bramble-core/src/main/java/org/briarproject/bramble/db/Database.java

@@ -162,6 +162,18 @@ interface Database<T> {
 	KeySetId addTransportKeys(T txn, PendingContactId p, TransportKeys k)
 			throws DbException;
 
+	/**
+	 * Returns true if there are any acks or messages to send to the given
+	 * contact over a transport with the given maximum latency.
+	 * <p/>
+	 * Read-only.
+	 *
+	 * @param eager True if messages that are not yet due for retransmission
+	 * should be included
+	 */
+	boolean containsAnythingToSend(T txn, ContactId c, int maxLatency,
+			boolean eager) throws DbException;
+
 	/**
 	 * Returns true if the database contains the given contact for the given
 	 * local pseudonym.

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java

@@ -341,6 +341,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.addTransportKeys(txn, p, k);
 	}
 
+	@Override
+	public boolean containsAnythingToSend(Transaction transaction, ContactId c,
+			int maxLatency, boolean eager) throws DbException {
+		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
+		return db.containsAnythingToSend(txn, c, maxLatency, eager);
+	}
+
 	@Override
 	public boolean containsContact(Transaction transaction, AuthorId remote,
 			AuthorId local) throws DbException {

bramble-core/src/main/java/org/briarproject/bramble/db/JdbcDatabase.java

@@ -1127,6 +1127,55 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public boolean containsAnythingToSend(Connection txn, ContactId c,
+			int maxLatency, boolean eager) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT NULL FROM statuses"
+					+ " WHERE contactId = ? AND ack = TRUE";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			rs = ps.executeQuery();
+			boolean acksToSend = rs.next();
+			rs.close();
+			ps.close();
+			if (acksToSend) return true;
+			if (eager) {
+				sql = "SELECT NULL from statuses"
+						+ " WHERE contactId = ? AND state = ?"
+						+ " AND groupShared = TRUE AND messageShared = TRUE"
+						+ " AND deleted = FALSE AND seen = FALSE";
+				ps = txn.prepareStatement(sql);
+				ps.setInt(1, c.getInt());
+				ps.setInt(2, DELIVERED.getValue());
+			} else {
+				long now = clock.currentTimeMillis();
+				long eta = now + maxLatency;
+				sql = "SELECT NULL FROM statuses"
+						+ " WHERE contactId = ? AND state = ?"
+						+ " AND groupShared = TRUE AND messageShared = TRUE"
+						+ " AND deleted = FALSE AND seen = FALSE"
+						+ " AND (expiry <= ? OR eta > ?)";
+				ps = txn.prepareStatement(sql);
+				ps.setInt(1, c.getInt());
+				ps.setInt(2, DELIVERED.getValue());
+				ps.setLong(3, now);
+				ps.setLong(4, eta);
+			}
+			rs = ps.executeQuery();
+			boolean messagesToSend = rs.next();
+			rs.close();
+			ps.close();
+			return messagesToSend;
+		} catch (SQLException e) {
+			tryToClose(rs, LOG, WARNING);
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public boolean containsContact(Connection txn, AuthorId remote,
 			AuthorId local) throws DbException {

bramble-core/src/main/java/org/briarproject/bramble/plugin/file/RemovableDriveManagerImpl.java

@@ -1,6 +1,8 @@
 package org.briarproject.bramble.plugin.file;
 
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.file.RemovableDriveManager;
@@ -14,12 +16,15 @@ import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.plugin.file.RemovableDrivePluginFactory.MAX_LATENCY;
+
 @ThreadSafe
 @NotNullByDefault
 class RemovableDriveManagerImpl
 		implements RemovableDriveManager, RemovableDriveTaskRegistry {
 
 	private final Executor ioExecutor;
+	private final DatabaseComponent db;
 	private final RemovableDriveTaskFactory taskFactory;
 	private final Object lock = new Object();
 
@@ -30,8 +35,9 @@ class RemovableDriveManagerImpl
 
 	@Inject
 	RemovableDriveManagerImpl(@IoExecutor Executor ioExecutor,
-			RemovableDriveTaskFactory taskFactory) {
+			DatabaseComponent db, RemovableDriveTaskFactory taskFactory) {
 		this.ioExecutor = ioExecutor;
+		this.db = db;
 		this.taskFactory = taskFactory;
 	}
 
@@ -74,6 +80,12 @@ class RemovableDriveManagerImpl
 		return created;
 	}
 
+	@Override
+	public boolean isWriterTaskNeeded(ContactId c) throws DbException {
+		return db.transactionWithResult(true, txn ->
+				db.containsAnythingToSend(txn, c, MAX_LATENCY, true));
+	}
+
 	@Override
 	public void removeReader(RemovableDriveTask task) {
 		synchronized (lock) {

bramble-core/src/main/java/org/briarproject/bramble/plugin/file/RemovableDrivePluginFactory.java

@@ -17,7 +17,7 @@ import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.I
 @NotNullByDefault
 public class RemovableDrivePluginFactory implements SimplexPluginFactory {
 
-	private static final int MAX_LATENCY = (int) DAYS.toMillis(14);
+	static final int MAX_LATENCY = (int) DAYS.toMillis(14);
 
 	@Inject
 	RemovableDrivePluginFactory() {