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// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
#pragma once
/*! \file rx-repeat.hpp
\brief Repeat this observable for the given number of times or infinitely.
\tparam Count the type of the counter (optional).
\param t The number of times the source observable items are repeated (optional). If not specified, infinitely repeats the source observable. Specifying 0 returns an empty sequence immediately
\return An observable that repeats the sequence of items emitted by the source observable for t times.
\sample
\snippet repeat.cpp repeat count sample
\snippet output.txt repeat count sample
If the source observable calls on_error, repeat stops:
\snippet repeat.cpp repeat error sample
\snippet output.txt repeat error sample
*/
#if !defined(RXCPP_OPERATORS_RX_REPEAT_HPP)
#define RXCPP_OPERATORS_RX_REPEAT_HPP
#include "../rx-includes.hpp"
namespace rxcpp {
namespace operators {
namespace detail {
template<class... AN>
struct repeat_invalid_arguments {};
template<class... AN>
struct repeat_invalid : public rxo::operator_base<repeat_invalid_arguments<AN...>> {
using type = observable<repeat_invalid_arguments<AN...>, repeat_invalid<AN...>>;
};
template<class... AN>
using repeat_invalid_t = typename repeat_invalid<AN...>::type;
// Contain repeat variations in a namespace
namespace repeat {
// Structure to perform general repeat 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->out.remove(state->lifetime_token);
state->source_lifetime.unsubscribe();
state->source_lifetime = composite_subscription();
state->lifetime_token = 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->out.on_error(e);
},
// on_completed
[state]() {
state->update();
// Use specialized predicate for finite/infinte case
if (state->completed_predicate()) {
state->out.on_completed();
} else {
state->do_subscribe();
}
}
);
}
composite_subscription source_lifetime;
output_type out;
composite_subscription::weak_subscription lifetime_token;
};
// Finite repeat case (explicitely 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)) {
}
inline bool completed_predicate() const {
// Return true if we are completed
return remaining_ <= 0;
}
inline void update() {
// Decrement counter
--remaining_;
}
source_type source;
private:
// Counter to hold number of times remaining to complete
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()) {
// return completed
state->out.on_completed();
} else {
// start the first iteration
state->do_subscribe();
}
}
private:
values initial_;
};
// Infinite repeat 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 repeat never completes
return false;
}
static inline void update() {
// Infinite repeat 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-repeat.hpp
*/
template<class... AN>
auto repeat(AN&&... an)
-> operator_factory<repeat_tag, AN...> {
return operator_factory<repeat_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
}
}
template<>
struct member_overload<repeat_tag> {
template<class Observable,
class Enabled = rxu::enable_if_all_true_type_t<is_observable<Observable>>,
class SourceValue = rxu::value_type_t<Observable>,
class Repeat = rxo::detail::repeat::infinite<SourceValue, rxu::decay_t<Observable>>,
class Value = rxu::value_type_t<Repeat>,
class Result = observable<Value, Repeat>>
static Result member(Observable&& o) {
return Result(Repeat(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 Repeat = rxo::detail::repeat::finite<SourceValue, rxu::decay_t<Observable>, rxu::decay_t<Count>>,
class Value = rxu::value_type_t<Repeat>,
class Result = observable<Value, Repeat>>
static Result member(Observable&& o, Count&& c) {
return Result(Repeat(std::forward<Observable>(o), std::forward<Count>(c)));
}
template<class... AN>
static operators::detail::repeat_invalid_t<AN...> member(AN...) {
std::terminate();
return {};
static_assert(sizeof...(AN) == 10000, "repeat takes (optional Count)");
}
};
}
#endif
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