An optional atomic value is cleared with an empty set instead of a nil
set. Thus use an empty set as an original empty value so that when an op
that sets a value is merged with an op that clears the value, the
comparison with an empty orignal value results in a noop.

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

The number of results of a transaction should always have a minimum
length of the number of operations passed to it even if there is an
error. The recent introduction of the named UUID expansion in the
transaction broke this requirement. Changed the error handling approach
so that this is less likely to happen in the future.

Also removed the panic when initializing the transaction cache.

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

The main purpose of this change is to have a package for common database
types and interfaces that can be used throughout the project without
incurring in circular dependencies.

To that end, the in-memory database implementation is moved to its own
subpackage.

The transaction implementation is also moved to its own subpackage given
that it can work with any database implementing the Database interface.

At the interface level though it should be expected that a transaction
implementation could have a more tighter underlying coupling with a
database implementation. So it makes sense to introduce a transaction
interface, and for transactions to be provided by database
implementations rather than being built directly by the server.

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Once we introduce referential integrity, existing tests would start to
fail as they are not accounting for it. So its better to remove the
references from the test schema which is something that current tests
are not leveraging, and then expand the schema with other references
that the referenctial integrity tests would leverage.

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Add the isRoot flag to the schema which will be used for referential
integrity

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Implement referential integrity and garbage collection as described in
RFC7047.

This is achieved keeping track of inverse references. A reference
tracker is used in the transaction to keep these references updated, to
check for referential integrity related violations and to add additional
updates to the transaction resulting from reference garbage collection.

The inverse references are stored in the database on commit.

The updates resulting from reference garbage collection are also sent to
any monitoring clients as expected.

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Provides coverage for the interaction of reference garbage collection
with index constraint checks.

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

While these tests could have been purely server tests, setting them up
as integration tests against both the test server and the real OVSDB
server allows us to contrast the implemented behavior.

Also provides coverage for how the references are updated in the
database as well as for how referential integrity updates are sent back
to the client.

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>

Signed-off-by: Jaime Caamaño Ruiz <[email protected]>