Stub in even subscriber.

include/bitcoin/node/chasers/chaser.hpp

@@ -28,49 +28,34 @@ namespace node {
 class full_node;
 
 /// Abstract base chaser.
+
+/// Chasers impose order on blockchain/pool construction as necessary.
+
 /// Each chaser operates on its own strand, implemented here, allowing
 /// concurrent chaser operations to the extent that threads are available.
+
+/// Events are passed between chasers using the full_node shared notifier.
+/// Notifications are bounced from sink (e.g. chaser) to its strand, and
+/// full_node::notify bounces from source (e.g. chaser) to network strand.
+
 class BCN_API chaser
   : public network::enable_shared_from_base<chaser>,
     public network::reporter
 {
 public:
-    typedef uint64_t object_key;
-    typedef network::desubscriber<object_key> subscriber;
-    typedef subscriber::handler notifier;
     DELETE_COPY_MOVE(chaser);
 
-    /// Start/stop.
-    /// -----------------------------------------------------------------------
-    void start(network::result_handler&& handler) NOEXCEPT;
-    void stop() NOEXCEPT;
-
-    /// Subscriptions.
-    /// -----------------------------------------------------------------------
-    object_key subscribe(notifier&& handler) NOEXCEPT;
-    bool notify(object_key key) NOEXCEPT;
-
-    /// Properties.
-    /// -----------------------------------------------------------------------
-    bool stopped() const NOEXCEPT;
-    bool stranded() const NOEXCEPT;
+    /// True if the current thread is on the chaser strand.
+    virtual bool stranded() const NOEXCEPT;
 
 protected:
     chaser(full_node& node) NOEXCEPT;
     virtual ~chaser() NOEXCEPT;
 
 private:
-    object_key create_key() NOEXCEPT;
-    void do_stop() NOEXCEPT;
-
     // These are thread safe (mostly).
     full_node& node_;
     network::asio::strand strand_;
-    std::atomic_bool stopped_{ true };
-
-    // These are protected by the strand.
-    object_key keys_{};
-    subscriber subscriber_;
 };
 
 } // namespace node

include/bitcoin/node/full_node.hpp

@@ -35,6 +35,7 @@ class BCN_API full_node
     typedef std::shared_ptr<full_node> ptr;
     typedef database::store<database::map> store;
     typedef database::query<store> query;
+    typedef network::subscriber<> event_subscriber;
 
     /// Constructors.
     /// -----------------------------------------------------------------------
@@ -78,6 +79,9 @@ class BCN_API full_node
     // These are thread safe.
     const configuration& config_;
     query& query_;
+
+    // This is protected by strand.
+    event_subscriber event_subscriber_;
 };
 
 } // namespace node

src/chasers/chaser.cpp

@@ -30,84 +30,19 @@ BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
 chaser::chaser(full_node& node) NOEXCEPT
   : node_(node),
     strand_(node.service().get_executor()),
-    subscriber_(strand_),
     reporter(node.log)
 {
 }
 
 chaser::~chaser() NOEXCEPT
 {
-    BC_ASSERT_MSG(stopped(), "The chaser was not stopped.");
-    if (!stopped()) { LOGF("~chaser is not stopped."); }
-}
-
-void chaser::start(network::result_handler&& handler) NOEXCEPT
-{
-    if (!stopped())
-    {
-        handler(network::error::operation_failed);
-        return;
-    }
-
-    stopped_.store(false);
-    handler(network::error::success);
-}
-
-void chaser::stop() NOEXCEPT
-{
-    stopped_.store(true);
-
-    // The chaser can be deleted once threadpool joins after this call.
-    boost::asio::post(strand_,
-        std::bind(&chaser::do_stop, this));
-}
-
-chaser::object_key chaser::subscribe(notifier&& handler) NOEXCEPT
-{
-    BC_ASSERT_MSG(stranded(), "strand");
-    const auto key = create_key();
-    subscriber_.subscribe(std::move(handler), key);
-    return key;
-}
-
-// TODO: closing channel notifies itself to desubscribe.
-bool chaser::notify(object_key key) NOEXCEPT
-{
-    return subscriber_.notify_one(key, network::error::success);
-}
-
-bool chaser::stopped() const NOEXCEPT
-{
-    return stopped_.load();
 }
 
 bool chaser::stranded() const NOEXCEPT
 {
     return strand_.running_in_this_thread();
 }
 
-// private
-chaser::object_key chaser::create_key() NOEXCEPT
-{
-    BC_ASSERT_MSG(stranded(), "strand");
-
-    if (is_zero(++keys_))
-    {
-        BC_ASSERT_MSG(false, "overflow");
-        LOGF("Chaser object overflow.");
-    }
-
-    return keys_;
-}
-
-// private
-void chaser::do_stop() NOEXCEPT
-{
-    BC_ASSERT_MSG(stranded(), "strand");
-
-    subscriber_.stop(network::error::service_stopped);
-}
-
 BC_POP_WARNING()
 
 } // namespace database

src/full_node.cpp

@@ -32,12 +32,13 @@ BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
 using namespace network;
 using namespace std::placeholders;
 
-// TODO: replace channel_heartbeat.
+// p2p::strand() as it is non-virtual (safe to call from constructor).
 full_node::full_node(query& query, const configuration& configuration,
     const logger& log) NOEXCEPT
   : p2p(configuration.network, log),
     config_(configuration),
-    query_(query)
+    query_(query),
+    event_subscriber_(strand())
 {
 }