Cache and settings 2.0 (next generation) T267

[KWB]

General:

• Technically there is no difference between settings/cache. The usage is different
• Make data persistent (i.e. save in file)
• Distribute via DBus if required

Scenarios:

• 1 swift app, object shared between threads
• swift pilot client + core same machine, object shared between processes, can be distributed via DBus or share the file
• swift pilot client + core 2 machines, object needs to be shared between processes
• 2 swift apps, like mapping tool and pilot client, 2 process, can be shared via file on same machine

Object types:

• Primitives: int, QString, ...
• value object
• value object container
• in theory we could just use CVariant to handle all

Metadata (query without reading the object, especially needed for large containers)

• timestamp, last changed
• for containers, size (count)

With T285 and T292 we have learnt:

• the model set / model caches for each simulator are the(!) most important use case
• they exist for each simulator
• it looks like a single in memory provider for these caches (as with T292 implemented as CCentralMultiSimulatorModelCachesProvider and ..ModelSetProvider) is the better approach, but it has to be thread safe!
• The question is, if we somehow implement the model set/caches, how many real other use cases do we have apart from the model caches? In other words, are there any other use cases for caches than than the model caches?