Save queue state before delivering message. #272

Another attempt to fix #272...

See merge request !125

Transaction isolation. #272

When client transactions were implemented the DB's read-write lock was removed, exposing H2's transaction isolation semantics. The default isolation level is "read committed", which allows concurrent transactions to overwrite each other's updates. This was the cause of #272. Changing H2's isolation level to "serialisable" would have caused other problems.

The solution is to reintroduce the DB's read-write lock. The lock is acquired when starting a transaction and released when committing or rolling back a transaction. (We already use try/finally blocks to ensure every transaction is committed or rolled back.) Read-only transactions can share the lock. To avoid deadlock, transactions must not be started while holding other locks.

This patch adapts the key manager to the new locking rules. The rest of the code was already compliant. Transports are now added to the DB during the startup phase, which allows TransportAddedEvent and TransportRemovedEvent to be deleted.

Fixes #269, fixes #272.

See merge request !124

TransportPropertyValidatorTest

Tests for the TransportPropertyValidator ValidateMessage call.

See merge request !110

Fixes #270.

@color/briar_text_primary is used in a lot of places other than the settings screen - if we want to use grey text in the settings screen we'll need to find another way.

Also fixed some misspelled resource names and included the colours from the Briar palette in color.xml.

247 dagger 2

This MR in a nutshell replaces Guice and Roboguice with Dagger 2, which offers a lot more possibilities than is implemented in this branch, such as using lazy injections for performance purposes. With Dagger 2 all the magic happens at compile time, so no need to worry about unfulfilled injections at runtime, but due to restrictions I was forced to put injected test code into an Android module. We therefore have a new test module, `android-test`.

A consequence of using Dagger 2 is that we no longer have a view injector and I therefore had to replace those with manual references. 

Closes #247 

See merge request !118

Modified the project structure, removed module extension and went instead for a non-complete core dependency graph

Semi-encapsulated the core/api dependency graphs and created a proper structure to load eager singletons

Material design settings - alternative

Closes #206.

Alternative to !77 that does not rely on an additional external library. The two alternatives should be compared for backwards-compatibility specifically regarding the ringtone selector.

Includes code from https://github.com/consp1racy/android-support-preference
License: Apache License v2.0

See merge request !78

Message queues. #266

A message queue is a group shared by two devices that delivers messages from each device to the other in order. The first 64 bits of the message body contain a sequence number that's incremented for each message sent in a given direction. The incoming and outgoing sequence numbers and information about any messages received out of order and waiting to be delivered are stored in the group metadata.

See merge request !121

Includes code from https://github.com/consp1racy/android-support-preference
License: Apache License v2.0

Fix race condition when closing redundant Bluetooth sockets

The Bluetooth invitation code has a race condition: if Alice and Bob connect to each other at roughly the same time, they each consider their outgoing socket to be redundant and close it, resulting in both sockets being closed. This can be triggered pretty reliably by using two phones of the same model and pressing 'Continue' at the same time on both phones.

When more than one invitation socket is opened, Alice should pick which one to use and Bob should use whichever one Alice picks, which Bob can detect by trying to read from both sockets.

Hopefully the Bluetooth invitation code will be retired when #117 is merged, but I'm putting this up for review in case we need to keep Bluetooth as a fallback method.

See merge request !120