This is only a premature hack, since the whole structure of PanelManager is somewhat broken.
Moreover, the ViewLocator is not really ready for use yet, so this hack at least
allows us to "reach into" a top-level window and "grab" the pannel we need.
* have a dedicated "information hub" controller, which acts a receiver of "error log messages" on the UI-Bus
* let that controller in turn allocate an apropriate view on demand
The goal is to build a (in itself completely meaningless) ping-pong interaction
between the UI and Proc-Layer, for the purpose of driving the integration ahead.
The immediate challenge is how to create and place an apropriate "GuiComponentView",
i.e. a Tangible, which is connected to the UI-Bus with an predictable EntryID.
And the problem is to get that settled right now, without building the envisioned
generic framework for View allocation in the UI. When this is achieved,
it should be a rather small step to actually send those notifications over
the UI-Bus, which is basically implemented and ready by now.
right now this will just end up in the log, since not even the
notification display is implemented beyond the GuiNotification-facade.
Anyway, we get some kind of communication now for real, in the actual application
...because due of #211, we usually don't execute commands yet.
For now there is only the backdoor to prefix the command-ID with "test"
With this change, the TODO message appears now immediately after GUI start!
In the end, I decided against building a generic service here,
since it pretty much looks like a one-time problem.
Preferrably UI content will be pushed or pulled on demand,
rather than actively coding content from within the UI-Layer
...and while doing so, also re-check the state of the GTK toolkit initialisation.
Looks like we're still future-proof, while cunningly avoiding all this
Gnome-style "Application" blurb
I will abandon work on the ViewSpec DSL in current shape (everything fine with that)
and instead work on a general UI start-up and content population sequence.
From there, my intention is to return to the docks, the placement of views
and then finally to the TimelineView
This finishes the first round of design drafts in this area.
Right now it seems difficult to get any further, since most of
the actual view creation and management in the UI is not yet coded.
looks like I'm trapped with the choice between a convoluted API design
and an braindead and inefficient implementation. I am leaning towards the latter
looks like we're hitting a design mismatch here....
...and unfortunately I have to abandon this task now and concentrate
on preparation of my talk at LAC.2018 in June
it seems apropriate to move the base definition of gui::idi::Descriptor<VIEW>
into view-spec-dsl.hpp and only retain the actual DSL definitions in id-scheme.hpp
this is a (hopefully just temporary) workaround to deal with static initialisation
ordering problems. The original solution was cleaner from a code readability viewpoint,
however, when lib::Depend was used from static initialisation code, it could
be observed that the factory constructor was invoked after first use.
And while this did not interfer with the instance lifecycle management itself,
because the zero-initialisation of the instance (atomic) pointer did happen
beforehand, it would discard any special factory functions installed from such
a context (and this counts as bug for my taste).
seemingly this code was brittle: GCC-7 treats int64_t as long,
which leads to preferring the template specialisation over the
explicit version of the operator* -- which means the template
instantiation invokes itself.
The original goal for #1129 (ViewSpecDSL_test) is impossible to accomplish,
at least within our existing test framework. Thus I'll limit myself to coding
a clean-room integration test with purely synthetic DSL definitions and mock widgets
usually the ID is hard coded, but when re-throwing errors, it might be
from "somewhere else", which means it is possibly a NULL ptr.
In those cases we fall back to the cannonical ID of the error class.
My understanding is that in the standard use case, we precisely know what to expect
and just go ahead and perform the conversion. Thus it is pointless to introduce
fine grained distinctions. When the access fails, this always indicates some broken
application logic, and just raises an error.
With this solution, somewhere deep down within the implementation
the knowledge about the actual result type would be encoded into
the embedded VTable within a lib::variant. At interface level,
ther will be a double dispatch based on that result type
and the desired result type, leading either to a successful
access or an error response.
Problem is, we can not even compile the conversion in the "other branch".
Thus we need to find some way to pick the suitable branch at compile time.
Quite similar to the solution found for binding Rec<GenNode> onto a typed Tuple
Basically the mocking mechanism just switches the configuration
and then waits for the service to be accessed in order to cause acutual
instantiation of the mock service implementation. But sometimes we want
to prepare and rig the mock instance prior to the first invocation;
in such cases it can be handy just to trigger the lazy creating process
...reduce immediate coupling, since we do not really now what actions ElementAccess
will actually perform, and this is likely to remain this way for some time.
So just let it sit there are an on-demand dependency.
Moreover, create an (empty placeholder) implementation within WindowLocator.
So everything is set now for the actual implementation to be filled in
Attempt to find my way back to the point
where the digression regarding dependency-injection started.
As it turns out, this was a valuable digression, since we can rid ourselves
from lots of ad-hoc functionality, which basically does in a shitty way
what DependencyFactory now provides as standard solution
FIRST STEP is to expose the Navigator as generic "LocationQuery" service
through lib::Depend<LocationQuery>
more of a layout improvement, to avoid any code duplication.
The mechanics remain the same
- write an explicit specialisation
- trigger template intantiation within a dedicated translation unit
while switching various services to the new framework,
I noticed the requirement to create a service handle in not-yet-started mode
and then start it explicitly, maybe even from another thread. Thus I introduced
a no-arg default ctor for that purpose, but overlooked that the forwarding ctor
might also need zero arguments for default constructible service implementation
classes. Thus I've now introduced a marker ENUM for disambiguation
from now on, we'll have dedicated individual translation units (*cpp)
for each distinct interface proxy. All of these will include the
interfaceproxy.hpp, which now holds the boilerplate part of the code
and *must not be included* in anything else than interfac proxy
translation units. The reason is, we now *definie* (with external linkage)
implementations of the facade::Link ctor and dtor for each distinct
type of interface proxy. This allows to decouple the proxy definition code
from the service implementation code (which is crucial for plug-ins
like the GUI)
The recently rewritten lib::Depend front-end for service dependencies,
together with the configuration as lib::DependInject::ServiceInstance
provides all the necessary features and is even threadsafe.
Beyond that, the expectation is that also the instantiation of the
interface proxies can be simplified. The proxies themselves however
need to be hand-written as before
I am fully aware this change has some far reaching ramifications.
Effectively I am hereby abandoning the goal of a highly modularised Lumiera,
where every major component is mapped over the Interface-System. This was
always a goal I accepted only reluctantly, and my now years of experience
confirm my reservation: it will cost us lots of efforts just for the
sake of being "sexy".
SingletonRef was only invented because lib::Depend (or lib::Singleton at that time)
offered only on-demand initialisation, but could not attach to an external service.
But this is required for calling out at the implementation side of a
Lumiera Interface into the actual service implementation.
The recently created DependInject::ServiceInstance now fulfils this task way better
and is seamlessly integrated into the lib::Depend front-end
Actually this is on the implementation side only.
Since Layer-Separation-Interfaces route each call through a binding layer,
we get two Service-"Instances" to manage
- on the client side we have to route into the Lumiera Interface system
- on the implementation side the C-Language calls from the Interface system
need to get to the actual service implementation. The latter is now
managed and exposed via DependInject::ServiceInstance
...still using the FAKE implementation, not a real rules engine.
However, with the new Dependency-Injection framework we need to define
the actual class from the service-provider, not from some service-client.
This is more orthogonal, but we're forced to install a Lifecycle-Hook now,
in order to get this configuration into the system prior to any use
This is borderline yet acceptable;
A service might indeed depend on itself circularly
The concrete example is the Advice-System, which needs to push
the clean-up of AdviceProvicions into a static context. From there
the deleters need to call back into the AdviceSystem, since they have
no wey to find out, if this is an individual Advice being retracted,
or a mass-cleanup due to system shutdown.
Thus the DependencyFactory now invokes the actual deleter
prior to setting the instance-Ptr to NULL.
This sidesteps the whole issue with the ClassLock, which actually
must be already destroyed at that point, according to the C++ standard.
(since it was created on-demand, on first actual usage, *after* the
DependencyFactory was statically initialised). A workaround would be
to have the ctor of DependencyFactory actively pull and allocate the
Monitor for the ClassLock; however this seems a bit overingeneered
to deal with such a borderline issue
...and package the ZombieCheck as helper object.
Also rewrite the SyncClassLock_test to perform an
multithreaded contended test to prove the lock is shared and effective
Static initialisation and shutdown can be intricate; but in fact they
work quite precise and deterministic, once you understand the rules
of the game.
In the actual case at hand the ClassLock was already destroyed, and
it must be destroyed at that point, according to the standard. Simply
because it is created on-demand, *after* the initialisation of the
static DependencyFactory, which uses this lock, and so its destructor
must be called befor the dtor of DependencyFactory -- which is precisely
what happens.
So there is no need to establish a special secure "base runtime system",
and this whole idea is ill-guided. I'll thus close ticket #1133 as wontfix
Conflicts:
src/lib/dependable-base.hpp
When some dependency or singleton violates Lumiera's policy regarding destructors and shutdown,
we are unable to detect this violation reliably and produce a Fatal Error message.
This is due to lib::Depend's de-initialisating being itself tied to template generated
static variables, which unfortunately have a visibility scope beyond the translation unit
responsible for construction and clean-up.
- state-of-the-art implementation of access with Double Checked Locking + Atomics
- improved design for configuration of dependencies. Now at the provider, not the consumer
- support for exposing services with a lifecycle through the lib::Depend<SRV> front-end
...which declare DependencyFactory as friend.
Yes, we want to encourrage that usage pattern.
Problem is, std::is_constructible<X> gives a misleading result in that case.
We need to do the instantiation check within the scope of DependencyFactory
ideally we want
- just a plain unique_ptr
- but with custom deleter delegating to lib::Depend
- Depend can be made fried to support private ctor/dtor
- reset the instance-ptr on deletion
- always kill any instance
all these tests are ported by drop-in replacement
and should work afterwards exactly as before (and they do indeed)
A minor twist was spotted though (nice to have more unit tests indeed!):
Sometimes we want to pass a custom constructor *not* as modern-style lambda,
but rather as direct function reference, function pointer or even member
function pointer. However, we can not store those types into the closure
for later lazy invocation. This is basically the same twist I run into
yesterday, when modernising the thread-wrapper. And the solution is
similar. Our traits class _Fun<FUN> has a new typedef Functor
with a suitable functor type to be instantiated and copied. In case of
the Lambda this is the (anonymous) lamda class itself, but in case of
a function reference or pointer it is a std::function.
...which showed up under high system load.
The initialisation of the member variables for the check sum
could be delayed while the corresponding thread was already running
- polish the text in the TiddlyWiki
- integrate some new pages in the published documentation
Still mostly placeholder text with some indications
- fill in the relevant sections in the overview document
- adjust, expand and update the Doxygen comments
TODO: could convert the TiddlyWiki page to Asciidoc and
publish it mostly as-is. Especially the nice benchmarks
from yesterday :-D
This solution is considered correct by the experts.
Regarding the dependency-configuration part, we do not care too much about performance
and use the somewhat slower default memory ordering constraint
