1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
#pragma once
#if !defined(RXCPP_OPERATORS_RX_SWITCH_ON_NEXT_HPP)
#define RXCPP_OPERATORS_RX_SWITCH_ON_NEXT_HPP
#include "../rx-includes.hpp"
namespace rxcpp {
namespace operators {
namespace detail {
template<class T, class Observable, class Coordination>
struct switch_on_next
: public operator_base<typename std::decay<T>::type::value_type>
{
//static_assert(is_observable<Observable>::value, "switch_on_next requires an observable");
//static_assert(is_observable<T>::value, "switch_on_next requires an observable that contains observables");
typedef switch_on_next<T, Observable, Coordination> this_type;
typedef typename std::decay<T>::type source_value_type;
typedef typename std::decay<Observable>::type source_type;
typedef typename source_type::source_operator_type source_operator_type;
typedef source_value_type collection_type;
typedef typename collection_type::value_type collection_value_type;
typedef typename std::decay<Coordination>::type coordination_type;
typedef typename coordination_type::coordinator_type coordinator_type;
struct values
{
values(source_operator_type o, coordination_type sf)
: source_operator(std::move(o))
, coordination(std::move(sf))
{
}
source_operator_type source_operator;
coordination_type coordination;
};
values initial;
switch_on_next(const source_type& o, coordination_type sf)
: initial(o.source_operator, std::move(sf))
{
}
template<class Subscriber>
void on_subscribe(Subscriber scbr) const {
static_assert(is_subscriber<Subscriber>::value, "subscribe must be passed a subscriber");
typedef Subscriber output_type;
struct switch_state_type
: public std::enable_shared_from_this<switch_state_type>
, public values
{
switch_state_type(values i, coordinator_type coor, output_type oarg)
: values(i)
, source(i.source_operator)
, pendingCompletions(0)
, coordinator(std::move(coor))
, out(std::move(oarg))
{
}
observable<source_value_type, source_operator_type> source;
// on_completed on the output must wait until all the
// subscriptions have received on_completed
int pendingCompletions;
coordinator_type coordinator;
composite_subscription inner_lifetime;
output_type out;
};
auto coordinator = initial.coordination.create_coordinator(scbr.get_subscription());
// take a copy of the values for each subscription
auto state = std::shared_ptr<switch_state_type>(new switch_state_type(initial, std::move(coordinator), std::move(scbr)));
composite_subscription outercs;
// when the out observer is unsubscribed all the
// inner subscriptions are unsubscribed as well
state->out.add(outercs);
auto source = on_exception(
[&](){return state->coordinator.in(state->source);},
state->out);
if (source.empty()) {
return;
}
++state->pendingCompletions;
// this subscribe does not share the observer subscription
// so that when it is unsubscribed the observer can be called
// until the inner subscriptions have finished
auto sink = make_subscriber<collection_type>(
state->out,
outercs,
// on_next
[state](collection_type st) {
state->inner_lifetime.unsubscribe();
state->inner_lifetime = composite_subscription();
// when the out observer is unsubscribed all the
// inner subscriptions are unsubscribed as well
auto innerlifetimetoken = state->out.add(state->inner_lifetime);
state->inner_lifetime.add(make_subscription([state, innerlifetimetoken](){
state->out.remove(innerlifetimetoken);
--state->pendingCompletions;
}));
auto selectedSource = on_exception(
[&](){return state->coordinator.in(st);},
state->out);
if (selectedSource.empty()) {
return;
}
// this subscribe does not share the source subscription
// so that when it is unsubscribed the source will continue
auto sinkInner = make_subscriber<collection_value_type>(
state->out,
state->inner_lifetime,
// on_next
[state, st](collection_value_type ct) {
state->out.on_next(std::move(ct));
},
// on_error
[state](std::exception_ptr e) {
state->out.on_error(e);
},
//on_completed
[state](){
if (state->pendingCompletions == 1) {
state->out.on_completed();
}
}
);
auto selectedSinkInner = on_exception(
[&](){return state->coordinator.out(sinkInner);},
state->out);
if (selectedSinkInner.empty()) {
return;
}
++state->pendingCompletions;
selectedSource->subscribe(std::move(selectedSinkInner.get()));
},
// on_error
[state](std::exception_ptr e) {
state->out.on_error(e);
},
// on_completed
[state]() {
if (--state->pendingCompletions == 0) {
state->out.on_completed();
}
}
);
auto selectedSink = on_exception(
[&](){return state->coordinator.out(sink);},
state->out);
if (selectedSink.empty()) {
return;
}
source->subscribe(std::move(selectedSink.get()));
}
};
template<class Coordination>
class switch_on_next_factory
{
typedef typename std::decay<Coordination>::type coordination_type;
coordination_type coordination;
public:
switch_on_next_factory(coordination_type sf)
: coordination(std::move(sf))
{
}
template<class Observable>
auto operator()(Observable source)
-> observable<typename switch_on_next<typename Observable::value_type, Observable, Coordination>::value_type, switch_on_next<typename Observable::value_type, Observable, Coordination>> {
return observable<typename switch_on_next<typename Observable::value_type, Observable, Coordination>::value_type, switch_on_next<typename Observable::value_type, Observable, Coordination>>(
switch_on_next<typename Observable::value_type, Observable, Coordination>(std::move(source), coordination));
}
};
}
template<class Coordination>
auto switch_on_next(Coordination&& sf)
-> detail::switch_on_next_factory<Coordination> {
return detail::switch_on_next_factory<Coordination>(std::forward<Coordination>(sf));
}
}
}
#endif
|
