1 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
2
3 #pragma once
4
5 /*! \file rx-ignore_elements.hpp
6
7 \brief Do not emit any items from the source Observable, but allow termination notification (either onError or onCompleted) to pass through unchanged.
8
9 \return Observable that emits termination notification from the source observable.
10
11 \sample
12 \snippet ignore_elements.cpp ignore_elements sample
13 \snippet output.txt ignore_elements sample
14 */
15
16 #if !defined(RXCPP_OPERATORS_RX_IGNORE_ELEMENTS_HPP)
17 #define RXCPP_OPERATORS_RX_IGNORE_ELEMENTS_HPP
18
19 #include "../rx-includes.hpp"
20
21 namespace rxcpp {
22
23 namespace operators {
24
25 namespace detail {
26
27 template<class... AN>
28 struct ignore_elements_invalid_arguments {};
29
30 template<class... AN>
31 struct ignore_elements_invalid : public rxo::operator_base<ignore_elements_invalid_arguments<AN...>> {
32 using type = observable<ignore_elements_invalid_arguments<AN...>, ignore_elements_invalid<AN...>>;
33 };
34 template<class... AN>
35 using ignore_elements_invalid_t = typename ignore_elements_invalid<AN...>::type;
36
37 template<class T>
38 struct ignore_elements {
39 typedef rxu::decay_t<T> source_value_type;
40
41 template<class Subscriber>
42 struct ignore_elements_observer
43 {
44 typedef ignore_elements_observer<Subscriber> this_type;
45 typedef source_value_type value_type;
46 typedef rxu::decay_t<Subscriber> dest_type;
47 typedef observer<value_type, this_type> observer_type;
48 dest_type dest;
49
ignore_elements_observerrxcpp::operators::detail::ignore_elements::ignore_elements_observer50 ignore_elements_observer(dest_type d)
51 : dest(d)
52 {
53 }
54
on_nextrxcpp::operators::detail::ignore_elements::ignore_elements_observer55 void on_next(source_value_type) const {
56 // no-op; ignore element
57 }
58
on_errorrxcpp::operators::detail::ignore_elements::ignore_elements_observer59 void on_error(rxu::error_ptr e) const {
60 dest.on_error(e);
61 }
62
on_completedrxcpp::operators::detail::ignore_elements::ignore_elements_observer63 void on_completed() const {
64 dest.on_completed();
65 }
66
makerxcpp::operators::detail::ignore_elements::ignore_elements_observer67 static subscriber<value_type, observer_type> make(dest_type d) {
68 return make_subscriber<value_type>(d, this_type(d));
69 }
70 };
71
72 template<class Subscriber>
operator ()rxcpp::operators::detail::ignore_elements73 auto operator()(Subscriber dest) const
74 -> decltype(ignore_elements_observer<Subscriber>::make(std::move(dest))) {
75 return ignore_elements_observer<Subscriber>::make(std::move(dest));
76 }
77 };
78
79 }
80
81 /*! @copydoc rx-ignore_elements.hpp
82 */
83 template<class... AN>
ignore_elements(AN &&...an)84 auto ignore_elements(AN&&... an)
85 -> operator_factory<ignore_elements_tag, AN...> {
86 return operator_factory<ignore_elements_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
87 }
88
89 }
90
91 template<>
92 struct member_overload<ignore_elements_tag>
93 {
94 template<class Observable,
95 class SourceValue = rxu::value_type_t<Observable>,
96 class Enabled = rxu::enable_if_all_true_type_t<
97 is_observable<Observable>>,
98 class IgnoreElements = rxo::detail::ignore_elements<SourceValue>>
memberrxcpp::member_overload99 static auto member(Observable&& o)
100 -> decltype(o.template lift<SourceValue>(IgnoreElements())) {
101 return o.template lift<SourceValue>(IgnoreElements());
102 }
103
104 template<class... AN>
memberrxcpp::member_overload105 static operators::detail::ignore_elements_invalid_t<AN...> member(AN...) {
106 std::terminate();
107 return {};
108 static_assert(sizeof...(AN) == 10000, "ignore_elements takes no arguments");
109 }
110 };
111
112 }
113
114 #endif
115