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/**
* @file classic_callback_test.cpp
* @author Nat Goodspeed
* @date 2021-09-22
* @brief Test ClassicCallback and HeapClassicCallback.
*
* $LicenseInfo:firstyear=2021&license=viewerlgpl$
* Copyright (c) 2021, Linden Research, Inc.
* $/LicenseInfo$
*/
// Precompiled header
#include "linden_common.h"
// associated header
#include "classic_callback.h"
// STL headers
#include <iostream>
#include <string>
// std headers
// external library headers
// other Linden headers
#include "../test/lltut.h"
/*****************************************************************************
* example callback accepting only (void* userdata)
*****************************************************************************/
// callback_t is part of the specification of someAPI()
typedef void (*callback_t)(const char*, void*);
void someAPI(callback_t callback, void* userdata)
{
callback("called", userdata);
}
// C++ callable I want as the actual callback
struct MyCallback
{
void operator()(const char* msg, void*)
{
mMsg = msg;
}
void callback_with_extra(const std::string& extra, const char* msg)
{
mMsg = extra + ' ' + msg;
}
std::string mMsg;
};
// a function for which I want to bind other data
void callback_with_extra(const std::string& extra, void*)
{
std::cout << "callback_with_extra('" << extra << "', *)\n";
}
/*****************************************************************************
* example callback accepting several params, and void* userdata isn't first
*****************************************************************************/
typedef std::string (*complex_callback)(int, const char*, void*, double);
std::string otherAPI(complex_callback callback, void* userdata)
{
return callback(17, "hello world", userdata, 3.0);
}
// struct into which we can capture complex_callback params
static struct Data
{
void set(int i, const char* s, double f)
{
mi = i;
ms = s;
mf = f;
}
void clear() { set(0, "", 0.0); }
int mi;
std::string ms;
double mf;
} sData;
// C++ callable I want to pass
struct OtherCallback
{
std::string operator()(int num, const char* str, void*, double approx)
{
sData.set(num, str, approx);
return "hello back!";
}
};
/*****************************************************************************
* TUT
*****************************************************************************/
namespace tut
{
struct classic_callback_data
{
};
typedef test_group<classic_callback_data> classic_callback_group;
typedef classic_callback_group::object object;
classic_callback_group classic_callbackgrp("classic_callback");
template<> template<>
void object::test<1>()
{
set_test_name("ClassicCallback");
// engage someAPI(MyCallback())
auto ccb{ makeClassicCallback<callback_t>(MyCallback()) };
someAPI(ccb.get_callback(), ccb.get_userdata());
// Unfortunately, with the side effect confined to the bound
// MyCallback instance, that call was invisible. Bind a reference to a
// named instance by specifying a ref type.
MyCallback mcb;
ClassicCallback<callback_t, void*, MyCallback&> ccb2(mcb);
someAPI(ccb2.get_callback(), ccb2.get_userdata());
ensure_equals("failed to call through ClassicCallback", mcb.mMsg, "called");
// try with HeapClassicCallback
mcb.mMsg.clear();
auto hcbp{ makeHeapClassicCallback<callback_t>(mcb) };
someAPI(hcbp->get_callback(), hcbp->get_userdata());
ensure_equals("failed to call through HeapClassicCallback", mcb.mMsg, "called");
// lambda
// The tricky thing here is that a lambda is an unspecified type, so
// you can't declare a ClassicCallback<signature, void*, that type>.
mcb.mMsg.clear();
auto xcb(
makeClassicCallback<callback_t>(
[&mcb](const char* msg, void*)
{ mcb.callback_with_extra("extra", msg); }));
someAPI(xcb.get_callback(), xcb.get_userdata());
ensure_equals("failed to call lambda", mcb.mMsg, "extra called");
// engage otherAPI(OtherCallback())
OtherCallback ocb;
// Instead of specifying a reference type for the bound CALLBACK, as
// with ccb2 above, you can alternatively move the callable object
// into the ClassicCallback (of course AFTER any other reference).
// That's why OtherCallback uses external data for its observable side
// effect.
auto occb{ makeClassicCallback<complex_callback>(std::move(ocb)) };
std::string result{ otherAPI(occb.get_callback(), occb.get_userdata()) };
ensure_equals("failed to return callback result", result, "hello back!");
ensure_equals("failed to set int", sData.mi, 17);
ensure_equals("failed to set string", sData.ms, "hello world");
ensure_equals("failed to set double", sData.mf, 3.0);
}
} // namespace tut
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