Merge branch 'transactional-db' into 'master'

Transactional DB interface

See merge request briar/briar!945

bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java

@@ -76,6 +76,19 @@ public interface DatabaseComponent {
 	 */
 	void endTransaction(Transaction txn);
 
+	/**
+	 * Runs the given task within a transaction.
+	 */
+	<E extends Exception> void transaction(boolean readOnly,
+			DbRunnable<E> task) throws DbException, E;
+
+	/**
+	 * Runs the given task within a transaction and returns the result of the
+	 * task.
+	 */
+	<R, E extends Exception> R transactionWithResult(boolean readOnly,
+			DbCallable<R, E> task) throws DbException, E;
+
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
 	 * and returns an ID for the contact.

bramble-api/src/main/java/org/briarproject/bramble/api/db/DbCallable.java

@@ -0,0 +1,6 @@
+package org.briarproject.bramble.api.db;
+
+public interface DbCallable<R, E extends Exception> {
+
+	R call(Transaction txn) throws DbException, E;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/db/DbRunnable.java

@@ -0,0 +1,6 @@
+package org.briarproject.bramble.api.db;
+
+public interface DbRunnable<E extends Exception> {
+
+	void run(Transaction txn) throws DbException, E;
+}

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

@@ -9,7 +9,9 @@ import org.briarproject.bramble.api.contact.event.ContactVerifiedEvent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbCallable;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.DbRunnable;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.db.NoSuchContactException;
@@ -166,6 +168,31 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			for (Event e : transaction.getEvents()) eventBus.broadcast(e);
 	}
 
+	@Override
+	public <E extends Exception> void transaction(boolean readOnly,
+			DbRunnable<E> task) throws DbException, E {
+		Transaction txn = startTransaction(readOnly);
+		try {
+			task.run(txn);
+			commitTransaction(txn);
+		} finally {
+			endTransaction(txn);
+		}
+	}
+
+	@Override
+	public <R, E extends Exception> R transactionWithResult(boolean readOnly,
+			DbCallable<R, E> task) throws DbException, E {
+		Transaction txn = startTransaction(readOnly);
+		try {
+			R result = task.call(txn);
+			commitTransaction(txn);
+			return result;
+		} finally {
+			endTransaction(txn);
+		}
+	}
+
 	private T unbox(Transaction transaction) {
 		if (transaction.isCommitted()) throw new IllegalStateException();
 		return txnClass.cast(transaction.unbox());

briar-core/src/main/java/org/briarproject/briar/forum/ForumManagerImpl.java

@@ -94,14 +94,7 @@ class ForumManagerImpl extends BdfIncomingMessageHook implements ForumManager {
 	@Override
 	public Forum addForum(String name) throws DbException {
 		Forum f = forumFactory.createForum(name);
-
+		db.transaction(false, txn -> db.addGroup(txn, f.getGroup()));
-		Transaction txn = db.startTransaction(false);
-		try {
-			db.addGroup(txn, f.getGroup());
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 		return f;
 	}
 
@@ -112,15 +105,11 @@ class ForumManagerImpl extends BdfIncomingMessageHook implements ForumManager {
 
 	@Override
 	public void removeForum(Forum f) throws DbException {
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> {
-		try {
 			for (RemoveForumHook hook : removeHooks)
 				hook.removingForum(txn, f);
 			db.removeGroup(txn, f.getGroup());
-			db.commitTransaction(txn);
+		});
-		} finally {
-			db.endTransaction(txn);
-		}
 	}
 
 	@Override
@@ -131,45 +120,35 @@ class ForumManagerImpl extends BdfIncomingMessageHook implements ForumManager {
 			p = forumPostFactory.createPost(groupId, timestamp, parentId,
 					author, body);
 		} catch (GeneralSecurityException | FormatException e) {
-			throw new RuntimeException(e);
+			throw new AssertionError(e);
 		}
 		return p;
 	}
 
 	@Override
 	public ForumPostHeader addLocalPost(ForumPost p) throws DbException {
-		Transaction txn = db.startTransaction(false);
+		db.transaction(false, txn -> {
-		try {
+			try {
-			BdfDictionary meta = new BdfDictionary();
+				BdfDictionary meta = new BdfDictionary();
-			meta.put(KEY_TIMESTAMP, p.getMessage().getTimestamp());
+				meta.put(KEY_TIMESTAMP, p.getMessage().getTimestamp());
-			if (p.getParent() != null) meta.put(KEY_PARENT, p.getParent());
+				if (p.getParent() != null) meta.put(KEY_PARENT, p.getParent());
-			Author a = p.getAuthor();
+				Author a = p.getAuthor();
-			meta.put(KEY_AUTHOR, clientHelper.toList(a));
+				meta.put(KEY_AUTHOR, clientHelper.toList(a));
-			meta.put(KEY_LOCAL, true);
+				meta.put(KEY_LOCAL, true);
-			meta.put(MSG_KEY_READ, true);
+				meta.put(MSG_KEY_READ, true);
-			clientHelper.addLocalMessage(txn, p.getMessage(), meta, true);
+				clientHelper.addLocalMessage(txn, p.getMessage(), meta, true);
-			messageTracker.trackOutgoingMessage(txn, p.getMessage());
+				messageTracker.trackOutgoingMessage(txn, p.getMessage());
-			db.commitTransaction(txn);
+			} catch (FormatException e) {
-		} catch (FormatException e) {
+				throw new AssertionError(e);
-			throw new RuntimeException(e);
+			}
-		} finally {
+		});
-			db.endTransaction(txn);
-		}
 		return new ForumPostHeader(p.getMessage().getId(), p.getParent(),
 				p.getMessage().getTimestamp(), p.getAuthor(), OURSELVES, true);
 	}
 
 	@Override
 	public Forum getForum(GroupId g) throws DbException {
-		Forum forum;
+		return db.transactionWithResult(true, txn -> getForum(txn, g));
-		Transaction txn = db.startTransaction(true);
-		try {
-			forum = getForum(txn, g);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return forum;
 	}
 
 	@Override
@@ -184,15 +163,9 @@ class ForumManagerImpl extends BdfIncomingMessageHook implements ForumManager {
 
 	@Override
 	public Collection<Forum> getForums() throws DbException {
+		Collection<Group> groups = db.transactionWithResult(true, txn ->
+				db.getGroups(txn, CLIENT_ID, MAJOR_VERSION));
 		try {
-			Collection<Group> groups;
-			Transaction txn = db.startTransaction(true);
-			try {
-				groups = db.getGroups(txn, CLIENT_ID, MAJOR_VERSION);
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
 			List<Forum> forums = new ArrayList<>();
 			for (Group g : groups) forums.add(parseForum(g));
 			return forums;
@@ -218,36 +191,35 @@ class ForumManagerImpl extends BdfIncomingMessageHook implements ForumManager {
 	@Override
 	public Collection<ForumPostHeader> getPostHeaders(GroupId g)
 			throws DbException {
-
-		Collection<ForumPostHeader> headers = new ArrayList<>();
-		Transaction txn = db.startTransaction(true);
 		try {
-			Map<MessageId, BdfDictionary> metadata =
+			return db.transactionWithResult(true, txn -> {
-					clientHelper.getMessageMetadataAsDictionary(txn, g);
+				Collection<ForumPostHeader> headers = new ArrayList<>();
-			// get all authors we need to get the status for
+				Map<MessageId, BdfDictionary> metadata =
-			Set<AuthorId> authors = new HashSet<>();
+						clientHelper.getMessageMetadataAsDictionary(txn, g);
-			for (Entry<MessageId, BdfDictionary> entry : metadata.entrySet()) {
+				// get all authors we need to get the status for
-				BdfList authorList = entry.getValue().getList(KEY_AUTHOR);
+				Set<AuthorId> authors = new HashSet<>();
-				Author a = clientHelper.parseAndValidateAuthor(authorList);
+				for (Entry<MessageId, BdfDictionary> entry :
-				authors.add(a.getId());
+						metadata.entrySet()) {
-			}
+					BdfList authorList = entry.getValue().getList(KEY_AUTHOR);
-			// get statuses for all authors
+					Author a = clientHelper.parseAndValidateAuthor(authorList);
-			Map<AuthorId, Status> statuses = new HashMap<>();
+					authors.add(a.getId());
-			for (AuthorId id : authors) {
+				}
-				statuses.put(id, identityManager.getAuthorStatus(txn, id));
+				// get statuses for all authors
-			}
+				Map<AuthorId, Status> statuses = new HashMap<>();
-			// Parse the metadata
+				for (AuthorId id : authors) {
-			for (Entry<MessageId, BdfDictionary> entry : metadata.entrySet()) {
+					statuses.put(id, identityManager.getAuthorStatus(txn, id));
-				BdfDictionary meta = entry.getValue();
+				}
-				headers.add(getForumPostHeader(txn, entry.getKey(), meta,
+				// Parse the metadata
-						statuses));
+				for (Entry<MessageId, BdfDictionary> entry :
-			}
+						metadata.entrySet()) {
-			db.commitTransaction(txn);
+					BdfDictionary meta = entry.getValue();
-			return headers;
+					headers.add(getForumPostHeader(txn, entry.getKey(), meta,
+							statuses));
+				}
+				return headers;
+			});
 		} catch (FormatException e) {
 			throw new DbException(e);
-		} finally {
-			db.endTransaction(txn);
 		}
 	}