We define a specialization of LLSDParam<const char*> to support passing an
LLSD object to a const char* function parameter. Needless to remark, passing
object.asString().c_str() would be Bad: destroying the temporary std::string
returned by asString() would immediately invalidate the pointer returned by
its c_str(). But when you pass LLSDParam<const char*>(object) as the
parameter, that specialization itself stores the std::string so the c_str()
pointer remains valid as long as the LLSDParam object does.
Then there's LLSDParam<LLSD>, used when we don't have the parameter type
available to select the LLSDParam specialization. LLSDParam<LLSD> defines a
templated conversion operator T() that constructs an LLSDParam<T> to provide
the actual parameter value. So far, so good.
The trouble was with the implementation of LLSDParam<LLSD>: it constructed a
_temporary_ LLSDParam<T>, implicitly called its operator T() and immediately
destroyed it. Destroying LLSDParam<const char*> destroyed its stored string,
thus invalidating the c_str() pointer before the target function was entered.
Instead, make LLSDParam<LLSD>::operator T() capture each LLSDParam<T> it
constructs, extending its lifespan to the lifespan of the LLSDParam<LLSD>
instance. For this, derive each LLSDParam specialization from LLSDParamBase, a
trivial base class that simply establishes the virtual destructor. We can then
capture any specialization as a pointer to LLSDParamBase.
Also restore LazyEventAPI tests on Mac.
LLSDParam<LLSD> is the generic case, when we need to pass LLSDParam adapters
to some set of function parameters whose types we don't specifically know. Its
templated conversion operator notices the actual parameter type T and
delegates conversion to the specific LLSDParam<T> specialization.
But when T has picked up references, e.g. somewhere along the way in the
LL::apply() machinery, the compiler might not choose the desired conversion
because we don't have a sufficiently specific LLSDParam specialization.
LLSDParam<LLSD> can address that by using std::decay_t<T> when delegating to
the specific LLSDParam specialization. This removes references, const and
volatile.
Add LL::always_return<T>(), which takes a callable and variadic arguments. It
calls the callable with those arguments and, if the returned type is
convertible to T, converts it and returns it. Otherwise it returns T().
always_return() is generalized from, and supersedes,
LLEventDispatcher::ReturnLLSD.
Add LL::function_arity<CALLABLE>, which extends
boost::function_types::function_arity by reporting results for both
std::function<CALLABLE> and boost::function<CALLABLE>. Use for
LL::apply(function, LLSD array) as well as for LLEventDispatcher.
Make LLEventDispatcher::add() overloads uniformly distinguish between a
callable (whether non-static member function or otherwise) that accepts a
single LLSD parameter, versus any other signature. Accepting exactly one LLSD
parameter signals that the callable will accept the composite arguments LLSD
blob, instead of asking LLEventDispatcher to unpack the arguments blob into
individual arguments.
Support add(subclass method) overloads for arbitrary-parameters methods as
well as for (const LLSD&) methods. Update tests accordingly: we need no longer
pass the boilerplate lambda instance getter that binds and returns 'this'.
Extract to the two LLEventDispatcher::make_invoker() overloads the LL::apply()
logic formerly found in ReturnLLSD.
Change lleventdispatcher_test.cpp tests from boost::bind(), which accepts
variadic arguments (even though it only passes a fixed set to the target
callable), to fixed-signature lambdas. This is because the revamped add()
overloads care about signature.
Add a test for a non-static method that accepts (const LLSD&), in other words
the composite arguments LLSD blob, and likewise returns LLSD.
(cherry picked from commit 95b787f7d7226ee9de79dfc9816f33c8bf199aad)
apply_n(function, LLSD array) has been useful, so for completeness, add the
corresponding function for std::vector.
Add a reference to apply_n() in comments for both apply() functions.
(cherry picked from commit dfb63a92e0e9a419931caf5112e1f590924e0867)
While calling a C++ function with arguments taken from a runtime-variable data
structure necessarily involves a bit of hocus-pocus, the best you can say for
the boost::fusion based implementation is that it worked. Sadly, template
recursion limited its applicability to a handful of function arguments. Now
that we have LL::apply(), use that instead. This implementation is much more
straightforward.
In particular, the LLSDArgsSource class, whose job was to dole out elements of
an LLSD array one at a time for the template recursion, goes away entirely.
Make virtual LLEventDispatcher::DispatchEntry::call() return LLSD instead of
void. All LLEventDispatcher target functions so far have been void; any
function that wants to respond to its invoker must do so explicitly by calling
sendReply() or constructing an LLEventAPI::Response instance. Supporting non-
void functions permits LLEventDispatcher to respond implicitly with the
returned value. Of course this requires a wrapper for void target functions
that returns LLSD::isUndefined().
Break out LLEventDispatcher::reply() from callFail(), so we can reply with
success as well as failure.
Make LLEventDispatcher::try_call_log() prepend the actual leaf class name and
description to any error returned by three-arg try_call(). That try_call()
overload reported "LLEventDispatcher(desc): " for a couple specific errors,
but no others. Hoist to try_call_log() to apply uniformly.
Introduce new try_call_one() method to diagnose name-not-found errors and
catch internal DispatchError and LL::apply_error exceptions. try_call_one()
returns a std::pair, containing either an error message or an LLSD value.
Make try_call_log() and three-arg try_call() accept LLSD 'name' instead of
plain std::string, allowing for the possibility of an array or map. That lets
us extend three-arg try_call() to break out new cases for the function selector
LLSD: isUndefined(), isArray(), isMap() and (current case) scalar String.
If try_call_one() reports an error, log it and try to send reply, as now. If
it returns LLSD::isUndefined(), e.g. from a void target function wrapper, do
nothing. But if it returns an LLSD map, try to send that back to the invoker.
And if it returns an LLSD scalar or array, wrap it in a map with key "data" to
respond to the invoker. Allowing a target function to return its result rather
than explicitly sending it opens the possibility of batched requests
(aggregate 'name') returning batched responses.
Almost every place that constructs LLEventDispatcher's internal DispatchError
exception called stringize() to format the what() string. Simplify calls by
making DispatchError accept variadic arguments and forward to stringize().
Add LL::invoke() to apply.h. Like LL::apply(), this is a (limited) C++14
foreshadowing of std::invoke(), with preprocessor conditionals to switch to
std::invoke() when that's available. Introduce LL::invoke() to handle a
callable that's actually a pointer to method.
Now our C++14 apply() implementation can accept pointer to method, using
invoke() to generalize the actual function call.
Also anticipate std::bind_front() with LL::bind_front(). For apply(func,
std::array) and our extensions apply(func, std::vector) and apply(func, LLSD),
we can't pass a pointer to method as the func unless the second argument
happens to be an array or vector of pointers (or references) to instances of
exactly the right class -- and of course LLSD can't store such at all. It's
tempting to pass std::bind(std::mem_fn(ptr_to_method), instance), but that
won't work: std::bind() requires a value or placeholder for each argument to
pass to the bound function. The bind() expression above would only work for a
nullary method. std::bind_front() would work, but that doesn't arrive until
C++20. Again, once we get there we'll defer to the std:: implementation.
Instead of the generic __cplusplus, check the appropriate feature-test macro
for availability of each of std::invoke(), std::apply() and std::bind_front().
Change apply() error handling from assert() to new LL::apply_error exception.
LLEventDispatcher must be able to intercept apply() errors. Move validation
and synthesis of the relevant error message to new apply.cpp source file.
Add to llptrto.h new LL::get_ref() and LL::get_ptr() template functions to
unify the cases of a calling template accepting either a pointer or a
reference. Wrapping the parameter in either get_ref() or get_ptr() allows
dereferencing the parameter as desired.
Move LL::apply(function, LLSD) argument validation/manipulation to a non-
template function in llsdutil.cpp: no need to replicate that logic in the
template for every CALLABLE specialization.
The trouble with passing bind_front(std::mem_fn(ptr_to_method), instance) to
apply() is that since bind_front() accepts and forwards variadic additional
arguments, apply() can't infer the arity of the bound ptr_to_method. Address
that by introducing apply_n<arity>(function, LLSD), permitting a caller to
infer the arity of ptr_to_method and explicitly pass it to apply_n().
Polish up lleventdispatcher_test.cpp accordingly. Wrong LLSD type and wrong
number of arguments now produce different (somewhat more informative) error
messages. Moreover, passing too many entries in an LLSD array used to work:
the extra arguments used to be ignored. Now we require that the size of the
array match the arity of the target function. Change the too-many-arguments
tests from success testing to error testing.
Replace 'foreach' aka BOOST_FOREACH macro invocations with range 'for'.
Replace STRINGIZE(item0 << item1 << ...) with stringize(item0, item1, ...).
(cherry picked from commit 9c049563b5480bb7e8ed87d9313822595b479c3b)
Add to apply_test.cpp a collect() function that incrementally accumulates an
arbitrary number of arguments into a std::vector<std::string>. Construct a
std::array<std::string> to pass it, using VAPPLY().
Clarify in header comments that LL::apply() can't call a variadic function
with arguments of dynamic size: std::vector or LLSD. The compiler can deduce
how many arguments to pass to a function with a fixed argument list; it can
deduce how many arguments to pass to a variadic function with a fixed number
of arguments. But it can't compile a call to a variadic function with an
arguments data structure whose size can vary at runtime.
(cherry picked from commit ceed33396266b123896f7cfb9b90abdf240e1eec)
Make apply(function, std::array) and apply(function, std::vector) available
even when we borrow the C++17 implementation of apply(function, std::tuple).
Add apply(function, LLSD) with interpretations:
* isUndefined() is treated as an empty array, for calling a nullary function
* scalar LLSD is treated as a single-entry array, for calling a unary function
* isArray() converts function parameters using LLSDParam
* isMap() is an error.
Add unit tests for all flavors of LL::apply().
(cherry picked from commit 3006c24251c6259d00df9e0f4f66b8a617e6026d)
Newer C++ compilers have different semantics around LLSDArray's special copy
constructor, which was essential to proper LLSD nesting. In short, we can no
longer trust LLSDArray to behave correctly. Now that we have variadic
functions, get rid of LLSDArray and replace every reference with llsd::array().
llsd::array(), as one might suspect, takes an arbitrary number of arguments of
arbitrary convertible types and returns an LLSD::Array constructed from those
elements. This supercedes the older LLSDArray class.
llsd::map() takes an even number of arguments paired as (LLSD::String,
arbitrary convertible type) and returns an LLSD::Map constructed from those
(key, value) pairs. This supercedes the older LLSDMap class.
These two functions not only have a simpler API -- arbitrary function
arguments rather than an (arg list)(arg list) sequence -- but also
specifically return a final LLSD object, rather than needing conversion to
LLSD from the LLSDArray or LLSDMap object.
Also support LLSD == LLSD and LLSD != LLSD comparisons, using llsd_equals()
with default exact-float-equality semantics.
We include both const and non-const overloads. The latter returns LLSD&, so
you can assign to the located element.
In fact we already implemented the non-const logic in a less public form as
storeToLLSDPath() in lleventcoro.cpp. Reimplement the latter to use the new
llsd::drill() function.
You can't directly write:
BOOST_FOREACH(LLSD item, someLLSDarray) { ... }
because LLSD has two distinct iteration mechanisms, one for arrays and one for
maps, neither using the standard [const_]iterator typedefs or begin()/end()
methods. But with these helpers, you can write:
BOOST_FOREACH(LLSD item, llsd::inArray(someLLSDarray)) { ... }
or
BOOST_FOREACH(const llsd::MapEntry& pair, llsd::inMap(someLLSDmap)) { ... }
These are in namespace llsd instead of being (e.g.) llsd_inMap because with a
namespace at least your .cpp file can have a local 'using':
using namespace llsd;
BOOST_FOREACH(LLSD item, inArray(someLLSDarray)) { ... }
It's namespace llsd rather than LLSD because LLSD can't be both a namespace
and a class name.
Nested LLSDArray expressions, e.g.:
LLSD array_of_arrays(LLSDArray(LLSDArray(17)(34))
(LLSDArray("x")("y")));
would quietly produce bad results because the outermost LLSDArray was being
constructed with the compiler's implicit LLSDArray(const LLSDArray&) rather
than LLSDArray(const LLSD&) as the reader assumes. Fixed with an explicit copy
constructor to Do The Right Thing.
Generalized LLSDParam<float> specialization into a macro to resolve similar
conversion ambiguities for float, LLUUID, LLDate, LLURI and LLSD::Binary.
Added optional bits= argument to llsd_equals() to permit comparing embedded
Real values using is_approx_equal_fraction() rather than strictly bitwise.
Omitting bits= retains current bitwise-comparison behavior.
LLSDArray is a helper to construct an LLSD::Array value inline.
LLSDMap is a helper to construct an LLSD::Map value inline.
LLSDParam is a customization point, a way for generic code to support
unforseen parameter types as conversion targets for LLSD values.
Ok, finally got this to a point where it doesn't break the build and I can check
in. llcommon can be built as a shared library (disabled but can be enabled with
cmake cache var LLCOMMON_LINK_SHARED.
reviewed by Mani on tuesday (I still need to get his suggested changes
re-reviewed)
Backport fixes made in the production branch to the trunk now that it is live on the grid:
* DEV-14443 Launcher not producing colo prefix when looking up sim class
* DEV-10840 "/etc/init.d/backbone stop" returns before all child backbones exited; "backbone restart" results in defunct children
* DEV-12558: Able to make anyone's object shout error messages
* QAR-483 user start location migration prelude
* QAR-490 havok4-6
* Revert havok4-5/4-6 code changes causing parcel access check issues
* Revert QAR-277 sqlite-backbone
* DEV-12357 SEC-53: Script that crashes regions
* QAR-486 New proc and query for Web Classifieds Fix
Andrey Lihatskiy