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
216
217
218
219
220
221
222
223
224
225
226
|
// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
#pragma once
/*! \file rx-retry.hpp
\brief Retry this observable for the given number of times.
\tparam Count the type of the counter (optional)
\param t the number of retries (optional) If not specified, infinitely retries the source observable. Sepcifying returns immediately without subscribing
\return An observable that mirrors the source observable, resubscribing to it if it calls on_error up to a specified number of retries.
\sample
\snippet retry.cpp retry count sample
\snippet output.txt retry count sample
*/
#if !defined(RXCPP_OPERATORS_RX_RETRY_HPP)
#define RXCPP_OPERATORS_RX_RETRY_HPP
#include "../rx-includes.hpp"
namespace rxcpp {
namespace operators {
namespace detail {
template<class... AN>
struct retry_invalid_arguments {};
template<class... AN>
struct retry_invalid : public rxo::operator_base<retry_invalid_arguments<AN...>> {
using type = observable<retry_invalid_arguments<AN...>, retry_invalid<AN...>>;
};
template<class... AN>
using retry_invalid_t = typename retry_invalid<AN...>::type;
// Contain retry variations in a namespace
namespace retry {
// Structure to perform general retry operations on state
template <class ValuesType, class Subscriber, class T>
struct state_type : public std::enable_shared_from_this<state_type<ValuesType, Subscriber, T>>,
public ValuesType {
typedef Subscriber output_type;
state_type(const ValuesType& i, const output_type& oarg)
: ValuesType(i)
, source_lifetime(composite_subscription::empty())
, out(oarg) {
}
void do_subscribe() {
auto state = this->shared_from_this();
state->source_lifetime = composite_subscription();
state->out.add(state->source_lifetime);
state->source.subscribe(
state->out,
state->source_lifetime,
// on_next
[state](T t) {
state->out.on_next(t);
},
// on_error
[state](std::exception_ptr e) {
state->update();
// Use specialized predicate for finite/infinte case
if (state->completed_predicate()) {
state->out.on_error(e);
} else {
state->do_subscribe();
}
},
// on_completed
[state]() {
// JEP: never appeears to be called?
state->out.on_completed();
}
);
}
composite_subscription source_lifetime;
output_type out;
};
// Finite retry case (explicitly limited with the number of times)
template<class T, class Observable, class Count>
struct finite : public operator_base<T> {
typedef rxu::decay_t<Observable> source_type;
typedef rxu::decay_t<Count> count_type;
struct values {
values(source_type s, count_type t)
: source(std::move(s)), remaining_(std::move(t)) {
if (remaining_ != 0) ++remaining_;
}
inline bool completed_predicate() const {
// Return true if we are completed
return remaining_ <= 0;
}
inline void update() {
// Decrement counter
--remaining_;
}
source_type source;
private:
count_type remaining_;
};
finite(source_type s, count_type t)
: initial_(std::move(s), std::move(t)) {
}
template<class Subscriber>
void on_subscribe(const Subscriber& s) const {
typedef state_type<values, Subscriber, T> state_t;
// take a copy of the values for each subscription
auto state = std::make_shared<state_t>(initial_, s);
if (initial_.completed_predicate()) {
// Should we call it here in retry?
state->out.on_completed();
} else {
// start the first iteration
state->do_subscribe();
}
}
private:
values initial_;
};
// Infinite retry case
template<class T, class Observable>
struct infinite : public operator_base<T> {
typedef rxu::decay_t<Observable> source_type;
struct values {
values(source_type s)
: source(std::move(s)) {
}
static inline bool completed_predicate() {
// Infinite retry never stops ignoring errors
return false;
}
static inline void update() {
// Infinite retry does not need to update state
}
source_type source;
};
infinite(source_type s) : initial_(std::move(s)) {
}
template<class Subscriber>
void on_subscribe(const Subscriber& s) const {
typedef state_type<values, Subscriber, T> state_t;
// take a copy of the values for each subscription
auto state = std::make_shared<state_t>(initial_, s);
// start the first iteration
state->do_subscribe();
}
private:
values initial_;
};
}
}
/*! @copydoc rx-retry.hpp
*/
template<class... AN>
auto retry(AN&&... an)
-> operator_factory<retry_tag, AN...> {
return operator_factory<retry_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
}
}
template<>
struct member_overload<retry_tag>
{
template<class Observable,
class Enabled = rxu::enable_if_all_true_type_t<is_observable<Observable>>,
class SourceValue = rxu::value_type_t<Observable>,
class Retry = rxo::detail::retry::infinite<SourceValue, rxu::decay_t<Observable>>,
class Value = rxu::value_type_t<Retry>,
class Result = observable<Value, Retry>
>
static Result member(Observable&& o) {
return Result(Retry(std::forward<Observable>(o)));
}
template<class Observable,
class Count,
class Enabled = rxu::enable_if_all_true_type_t<is_observable<Observable>>,
class SourceValue = rxu::value_type_t<Observable>,
class Retry = rxo::detail::retry::finite<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<Count>>,
class Value = rxu::value_type_t<Retry>,
class Result = observable<Value, Retry>
>
static Result member(Observable&& o, Count&& c) {
return Result(Retry(std::forward<Observable>(o), std::forward<Count>(c)));
}
template<class... AN>
static operators::detail::retry_invalid_t<AN...> member(const AN&...) {
std::terminate();
return {};
static_assert(sizeof...(AN) == 10000, "retry takes (optional Count)");
}
};
}
#endif
|
