LUMIERA.clone/tests/library/meta/late-bind-instance-test.cpp
Ichthyostega b61ca94ee5 Scheduler: rectify λ-post API
...to bring it more in line with all the other calls dealing with Activity*
...allows also to harmonise the ActivityLang::dispatchChain()
...and to compose the calls in Scheduler directly

NOTE: there is a twist: our string-formatting helper did not render
custom string conversions for objects passed as pointer. This was a
long standing problem, caused by ambiguous templates overloads;
now I've attempted to solve it one level more down, in util::StringConv.
This solution may turn out brittle, since we need to exclude any direct
string conversion, most notably the ones for C-Strings (const char*)

In case this solution turns out unsustainable, please feel free
to revert this API change, and return to passing Activity& in λ-post,
because in the end this is cosmetics.
2023-10-23 01:48:46 +02:00

195 lines
7 KiB
C++

/*
LateBindInstance(Test) - verify rewriting of member function invocation
Copyright (C) Lumiera.org
2023, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* *****************************************************/
/** @file late-bind-instance-test.cpp
** unit test \ref LateBindInstance_test
*/
#include "lib/test/run.hpp"
#include "lib/meta/function.hpp"
#include "lib/meta/tuple-helper.hpp"
#include "lib/test/test-helper.hpp"
#include "lib/test/testdummy.hpp"
#include "lib/format-cout.hpp"
#include "lib/format-util.hpp"
#include "lib/util.hpp"
#include <tuple>
#include <string>
#include <cstdlib>
namespace lib {
namespace meta {
namespace test {
using std::move;
using std::rand;
using std::tuple;
using std::string;
using lib::meta::dump;
using lib::test::Tracker;
/**********************************************************************************//**
* @test verify a scheme to supply the actual instance for member function invocation.
* @remark in the end this is just a value replacement in a tuple, where the position
* is marked with a placeholder type. This scheme is used for starting threads,
* where the actual thread instance is not known yet at the point where the
* arguments for the thread-function are constructed
* @see lib::launchDetached
*/
class LateBindInstance_test : public Test
{
void
run (Arg)
{
demonstrateUsage();
verify_forwarding();
verify_cornerCases();
}
/** @test demonstrate the usage of lib::meta::lateBindInstance():
* - construct an argument tuple
* - mark the position of the `this`-ptr with a placeholder
* - rewrite the arguments later when the actual instance is known
* - member function can now be invoked, since the instance was injected.
*/
void
demonstrateUsage()
{
uint randomLimit = 2 + rand() % 98;
auto plannedArgs
= tuple{InstancePlaceholder<LateBindInstance_test>{}
,randomLimit
};
// the actual instance may be available only later...
Test& instanceRef = *this;
// now rewrite the argument tuple to inject the instance-ptr
auto preparedArgs = lateBindInstance (instanceRef, plannedArgs);
uint res = std::apply (&LateBindInstance_test::theMember, preparedArgs);
CHECK (res < randomLimit);
}
uint
theMember (uint limit)
{
return rand() % limit;
}
/** @test verify that the rewriting process does not incur unnecessary data copies
*/
void
verify_forwarding()
{
auto& log = Tracker::log;
log.clear (this);
InstancePlaceholder<LateBindInstance_test> marker;
Tracker t1(11);
log.event("construct tuple");
tuple tup(t1, marker, Tracker{23}, 55);
Test& instanceRef = *this;
log.event("invoke lateBindInstance");
auto tup1r = lateBindInstance (instanceRef, tup);
log.event("got result");
// before invocation the Tracker instances are created (obviously..)
CHECK (log.verifyCall("ctor").arg(11)
.beforeCall("ctor-copy").arg("Track{11}")
.beforeEvent("invoke lateBindInstance"));
CHECK (log.verifyCall("ctor").arg(23)
.beforeCall("ctor-move").arg("Track{23}")
.beforeCall("dtor").arg(Tracker::DEFUNCT)
.beforeEvent("invoke lateBindInstance"));
// but there is no copy operation after the invocation
CHECK (log.ensureNot("ctor-copy")
.afterEvent("invoke lateBindInstance"));
// both Tracker instances are moved two times
// - once to create the maybeInject-invocation and
// - once to consolidate the result
// for each instance one moved-away temporary is destroyed
CHECK (log.verifyEvent("invoke lateBindInstance")
.beforeCall("ctor-move").arg("Track{11}")
.beforeCall("ctor-move").arg("Track{11}")
.beforeCall("dtor").arg(Tracker::DEFUNCT)
.beforeEvent("got result"));
CHECK (log.verifyEvent("invoke lateBindInstance")
.beforeCall("ctor-move").arg("Track{23}")
.beforeCall("ctor-move").arg("Track{23}")
.beforeCall("dtor").arg(Tracker::DEFUNCT)
.beforeEvent("got result"));
cout << "____Tracker-Log_______________\n"
<< util::join(Tracker::log, "\n")
<< "\n───╼━━━━━━━━━━━╾──────────────"<<endl;
}
/** @test replacement happens uniformly on all kinds of tuples
*/
void
verify_cornerCases()
{
long dummy{555};
InstancePlaceholder<long> marker;
CHECK (dump(lateBindInstance (dummy, tuple<>{})) == "()"_expect);
CHECK (dump(lateBindInstance (dummy, tuple{42})) == "(42)"_expect);
CHECK (dump(lateBindInstance (dummy, tuple{1,2,3})) == "(1,2,3)"_expect);
CHECK (dump(lateBindInstance (dummy, tuple{marker,2,3})) == "(↗555,2,3)"_expect);
CHECK (dump(lateBindInstance (dummy, tuple{1,marker,3})) == "(1,↗555,3)"_expect);
CHECK (dump(lateBindInstance (dummy, tuple{1,2,marker})) == "(1,2,↗555)"_expect);
CHECK (dump(lateBindInstance (dummy, tuple{marker})) == "(↗555)"_expect);
CHECK (dump(lateBindInstance (dummy, tuple{string{"1"}
,"2"
,marker
,tuple(2,3)
, 5.5
})) == "(1,2,↗555,«tuple<int, int>»──(2,3),5.5)"_expect);
}
};
/** Register this test class... */
LAUNCHER (LateBindInstance_test, "unit meta");
}}} // namespace lib::meta::test