Ichthyostega
f05ec78e08
This is essentially the solution we used since start of the Lumiera project. This solution is not entirely correct in theory, because the assignment to the instance pointer can be visible prior to releasing the Mutex -- so another thread might see a partially initialised object
116 lines
4.3 KiB
C++
116 lines
4.3 KiB
C++
/* try.cpp - for trying out some language features....
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* scons will create the binary bin/try
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*
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*/
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// 8/07 - how to control NOBUG??
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// execute with NOBUG_LOG='ttt:TRACE' bin/try
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// 1/08 - working out a static initialisation problem for Visitor (Tag creation)
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// 1/08 - check 64bit longs
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// 4/08 - comparison operators on shared_ptr<Asset>
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// 4/08 - conversions on the value_type used for boost::any
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// 5/08 - how to guard a downcasting access, so it is compiled in only if the involved types are convertible
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// 7/08 - combining partial specialisation and subclasses
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// 10/8 - abusing the STL containers to hold noncopyable values
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// 6/09 - investigating how to build a mixin template providing an operator bool()
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// 12/9 - tracking down a strange "warning: type qualifiers ignored on function return type"
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// 1/10 - can we determine at compile time the presence of a certain function (for duck-typing)?
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// 4/10 - pretty printing STL containers with python enabled GDB?
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// 1/11 - exploring numeric limits
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// 1/11 - integer floor and wrap operation(s)
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// 1/11 - how to fetch the path of the own executable -- at least under Linux?
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// 10/11 - simple demo using a pointer and a struct
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// 11/11 - using the boost random number generator(s)
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// 12/11 - how to detect if string conversion is possible?
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// 1/12 - is partial application of member functions possible?
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// 5/14 - c++11 transition: detect empty function object
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// 7/14 - c++11 transition: std hash function vs. boost hash
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// 9/14 - variadic templates and perfect forwarding
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// 11/14 - pointer to member functions and name mangling
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// 8/15 - Segfault when loading into GDB (on Debian/Jessie 64bit
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// 8/15 - generalising the Variant::Visitor
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// 1/16 - generic to-string conversion for ostream
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// 1/16 - build tuple from runtime-typed variant container
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// 3/17 - generic function signature traits, including support for Lambdas
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// 9/17 - manipulate variadic templates to treat varargs in several chunks
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// 11/17 - metaprogramming to detect the presence of extension points
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// 11/17 - detect generic lambda
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// 12/17 - investigate SFINAE failure. Reason was indirect use while in template instantiation
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// 03/18 - Dependency Injection / Singleton initialisation / double checked locking
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/** @file try.cpp
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** Rework of the template lib::Depend for singleton and service access.
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** The (now for the third time rewritten) dependency factory can be configured to yield
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** a subclass singleton, or to bind to an external service. Lazy initialisation relies on
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** Double Checked Locking, which we need switch to C++11 Atomics in order to be correct
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** (in theory). The impact of this initialisation guard should be investigated by benchmark.
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*/
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typedef unsigned int uint;
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#include "lib/format-cout.hpp"
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#include "lib/depend2.hpp"
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#include "lib/depend-inject.hpp"
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//#include "lib/meta/util.hpp"
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#include "lib/test/test-helper.hpp"
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#include "lib/util.hpp"
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#define SHOW_TYPE(_TY_) \
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cout << "typeof( " << STRINGIFY(_TY_) << " )= " << lib::meta::typeStr<_TY_>() <<endl;
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#define SHOW_EXPR(_XX_) \
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cout << "Probe " << STRINGIFY(_XX_) << " ? = " << _XX_ <<endl;
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namespace error = lumiera::error;
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using lib::Depend;
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using lib::DependInject;
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//////////////////////////////////////////////////////////////////////////Microbenchmark
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#include "lib/test/microbenchmark.hpp"
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using lib::test::microbenchmark;
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//////////////////////////////////////////////////////////////////////////(End)Microbenchmark
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#include "include/lifecycle.h"
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#include "lib/test/testoption.hpp"
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#include "lib/test/suite.hpp"
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using lumiera::LifecycleHook;
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using lumiera::ON_GLOBAL_INIT;
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using lumiera::ON_GLOBAL_SHUTDOWN;
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///////////////////////////////////////////////////////Usage
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class BlackHoleService
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: util::NonCopyable
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{
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volatile int theHole_ = rand() % 1000;
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public:
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int readMe() { return theHole_; }
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};
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int
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main (int, char**)
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{
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std::srand(std::time(nullptr));
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LifecycleHook::trigger (ON_GLOBAL_INIT);
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Depend<BlackHoleService> mystery;
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cout << microbenchmark<1> ([&]()
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{
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0 == mystery().readMe();
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}
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,1000000000)
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<< endl;
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LifecycleHook::trigger (ON_GLOBAL_SHUTDOWN);
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// cout << "\n.gulp.\n";
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return 0;
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}
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