added group_by

1 files changed, 220 insertions, 0 deletions

diff --git a/Rx/v2/src/rxcpp/operators/rx-group_by.hpp b/Rx/v2/src/rxcpp/operators/rx-group_by.hpp
new file mode 100644
index 0000000..3982e8b
--- /dev/null
+++ b/Rx/v2/src/rxcpp/operators/rx-group_by.hpp
@@ -0,0 +1,220 @@
+// 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_GROUP_BY_HPP)
+#define RXCPP_OPERATORS_RX_GROUP_BY_HPP
+
+#include "../rx-includes.hpp"
+
+namespace rxcpp {
+
+namespace operators {
+
+namespace detail {
+
+template<class T, class Selector>
+struct is_group_by_selector_for {
+
+    typedef typename std::decay<Selector>::type selector_type;
+    typedef T source_value_type;
+
+    struct tag_not_valid {};
+    template<class CV, class CS>
+    static auto check(int) -> decltype((*(CS*)nullptr)(*(CV*)nullptr));
+    template<class CV, class CS>
+    static tag_not_valid check(...);
+
+    typedef decltype(check<source_value_type, selector_type>(0)) type;
+    static const bool value = !std::is_same<type, tag_not_valid>::value;
+};
+
+template<class T, class Observable, class KeySelector, class MarbleSelector, class BinaryPredicate>
+struct group_by_traits
+{
+    typedef T source_value_type;
+    typedef typename std::decay<Observable>::type source_type;
+    typedef typename std::decay<KeySelector>::type key_selector_type;
+    typedef typename std::decay<MarbleSelector>::type marble_selector_type;
+    typedef typename std::decay<BinaryPredicate>::type predicate_type;
+
+    static_assert(is_group_by_selector_for<source_value_type, key_selector_type>::value, "group_by KeySelector must be a function with the signature key_type(source_value_type)");
+
+    typedef typename is_group_by_selector_for<source_value_type, key_selector_type>::type key_type;
+
+    static_assert(is_group_by_selector_for<source_value_type, marble_selector_type>::value, "group_by MarbleSelector must be a function with the signature marble_type(source_value_type)");
+
+    typedef typename is_group_by_selector_for<source_value_type, marble_selector_type>::type marble_type;
+
+    typedef rxsub::subject<marble_type> subject_type;
+
+    typedef std::map<key_type, typename subject_type::subscriber_type, predicate_type> key_subscriber_map_type;
+
+    typedef grouped_observable<key_type, source_value_type> grouped_observable_type;
+};
+
+template<class T, class Observable, class KeySelector, class MarbleSelector, class BinaryPredicate>
+struct group_by
+{
+    typedef group_by_traits<T, Observable, KeySelector, MarbleSelector, BinaryPredicate> traits_type;
+    typedef typename traits_type::key_selector_type key_selector_type;
+    typedef typename traits_type::marble_selector_type marble_selector_type;
+    typedef typename traits_type::predicate_type predicate_type;
+    typedef typename traits_type::subject_type subject_type;
+    typedef typename traits_type::key_type key_type;
+
+    struct group_by_values
+    {
+        group_by_values(key_selector_type ks, marble_selector_type ms, predicate_type p)
+            : keySelector(std::move(ks))
+            , marbleSelector(std::move(ms))
+            , predicate(std::move(p))
+        {
+        }
+        mutable key_selector_type keySelector;
+        mutable marble_selector_type marbleSelector;
+        mutable predicate_type predicate;
+    };
+
+    group_by_values initial;
+
+    group_by(key_selector_type ks, marble_selector_type ms, predicate_type p)
+        : initial(std::move(ks), std::move(ms), std::move(p))
+    {
+    }
+
+    struct group_by_observable
+    {
+        subject_type subject;
+        key_type key;
+
+        group_by_observable(subject_type s, key_type k)
+            : subject(std::move(s))
+            , key(k)
+        {
+        }
+
+        template<class Subscriber>
+        void on_subscribe(Subscriber&& o) const {
+            subject.get_observable().subscribe(std::forward<Subscriber>(o));
+        }
+
+        key_type on_get_key() {
+            return key;
+        }
+    };
+
+    template<class Subscriber>
+    struct group_by_observer : public group_by_values
+    {
+        typedef group_by_observer<Subscriber> this_type;
+        typedef typename traits_type::grouped_observable_type value_type;
+        typedef typename std::decay<Subscriber>::type dest_type;
+        typedef observer<T, this_type> observer_type;
+        dest_type dest;
+
+        mutable typename traits_type::key_subscriber_map_type groups;
+
+        group_by_observer(dest_type d, group_by_values v)
+            : group_by_values(v)
+            , dest(std::move(d))
+            , groups(group_by_values::predicate)
+        {
+        }
+        void on_next(T v) const {
+            auto selectedKey = on_exception(
+                [&](){
+                    return this->keySelector(v);},
+                *this);
+            if (selectedKey.empty()) {
+                return;
+            }
+            auto g = groups.find(selectedKey.get());
+            if (g == groups.end()) {
+                auto sub = subject_type();
+                g = groups.insert(std::make_pair(selectedKey.get(), sub.get_subscriber())).first;
+                dest.on_next(make_dynamic_grouped_observable<key_type, T>(group_by_observable(sub, selectedKey.get())));
+            }
+            auto selectedMarble = on_exception(
+                [&](){
+                    return this->marbleSelector(v);},
+                *this);
+            if (selectedMarble.empty()) {
+                return;
+            }
+            g->second.on_next(std::move(selectedMarble.get()));
+        }
+        void on_error(std::exception_ptr e) const {
+            (*this)(e);
+        }
+        void operator()(std::exception_ptr e) const {
+            for(auto& g : groups) {
+                g.second.on_error(e);
+            }
+            dest.on_error(e);
+        }
+        void on_completed() const {
+            for(auto& g : groups) {
+                g.second.on_completed();
+            }
+            dest.on_completed();
+        }
+
+        static subscriber<T, observer_type> make(dest_type d, group_by_values v) {
+            auto cs = d.get_subscription();
+            return make_subscriber<T>(std::move(cs), observer_type(this_type(std::move(d), std::move(v))));
+        }
+    };
+
+    template<class Subscriber>
+    auto operator()(Subscriber dest) const
+        -> decltype(group_by_observer<Subscriber>::make(std::move(dest), initial)) {
+        return      group_by_observer<Subscriber>::make(std::move(dest), initial);
+    }
+};
+
+template<class KeySelector, class MarbleSelector, class BinaryPredicate>
+class group_by_factory
+{
+    typedef typename std::decay<KeySelector>::type key_selector_type;
+    typedef typename std::decay<MarbleSelector>::type marble_selector_type;
+    typedef typename std::decay<BinaryPredicate>::type predicate_type;
+    key_selector_type keySelector;
+    marble_selector_type marbleSelector;
+    predicate_type predicate;
+public:
+    group_by_factory(key_selector_type ks, marble_selector_type ms, predicate_type p)
+        : keySelector(std::move(ks))
+        , marbleSelector(std::move(ms))
+        , predicate(std::move(p))
+    {
+    }
+    template<class Observable>
+    struct group_by_factory_traits
+    {
+        typedef typename Observable::value_type value_type;
+        typedef detail::group_by_traits<value_type, Observable, KeySelector, MarbleSelector, BinaryPredicate> traits_type;
+        typedef detail::group_by<value_type, Observable, KeySelector, MarbleSelector, BinaryPredicate> group_by_type;
+    };
+    template<class Observable>
+    auto operator()(Observable&& source)
+        -> decltype(source.template lift<typename group_by_factory_traits<Observable>::traits_type::grouped_observable_type>(typename group_by_factory_traits<Observable>::group_by_type(std::move(keySelector), std::move(marbleSelector), std::move(predicate)))) {
+        return      source.template lift<typename group_by_factory_traits<Observable>::traits_type::grouped_observable_type>(typename group_by_factory_traits<Observable>::group_by_type(std::move(keySelector), std::move(marbleSelector), std::move(predicate)));
+    }
+};
+
+}
+
+template<class KeySelector, class MarbleSelector, class BinaryPredicate>
+inline auto group_by(KeySelector ks, MarbleSelector ms, BinaryPredicate p)
+    ->      detail::group_by_factory<KeySelector, MarbleSelector, BinaryPredicate> {
+    return  detail::group_by_factory<KeySelector, MarbleSelector, BinaryPredicate>(std::move(ks), std::move(ms), std::move(p));
+}
+
+
+}
+
+}
+
+#endif
+