ulib/3party/rxcpp/Rx/v2/examples/doxygen/ref_count.cpp
2024-01-10 09:33:36 +08:00

56 lines
1.8 KiB
C++

#include "rxcpp/rx.hpp"
#include "rxcpp/rx-test.hpp"
#include "catch.hpp"
#include <array>
SCENARIO("ref_count other diamond sample"){
printf("//! [ref_count other diamond sample]\n");
/*
* Implements the following diamond graph chain with publish+ref_count without using threads.
* This version is composable because it does not use connect explicitly.
*
* Values
* / \
* *2 *100
* \ /
* Merge
* |
* RefCount
*/
std::array<double, 5> a={{1.0, 2.0, 3.0, 4.0, 5.0}};
auto values = rxcpp::observable<>::iterate(a)
// The root of the chain is only subscribed to once.
.tap([](double v) { printf("[0] OnNext: %lf\n", v); })
.publish();
auto values_to_long = values.map([](double v) { return (long) v; });
// Left side multiplies by 2.
auto left = values_to_long.map(
[](long v) -> long {printf("[1] OnNext: %ld -> %ld\n", v, v*2); return v * 2L;} );
// Right side multiplies by 100.
auto right = values_to_long.map(
[](long v) -> long {printf("[2] OnNext: %ld -> %ld\n", v, v*100); return v * 100L; });
// Merge the left,right sides together.
// The items are emitted interleaved ... [left1, right1, left2, right2, left3, right3, ...].
auto merged = left.merge(right);
// When this value is subscribed to, it calls connect on values.
auto connect_on_subscribe = merged.ref_count(values);
// This immediately starts emitting all values and blocks until they are completed.
connect_on_subscribe.subscribe(
[](long v) { printf("[3] OnNext: %ld\n", v); },
[&]() { printf("[3] OnCompleted:\n"); });
printf("//! [ref_count other diamond sample]\n");
}
// see also examples/doxygen/publish.cpp for non-ref_count diamonds