Refactor to stack allocate chasers.

include/bitcoin/node/chasers/chaser.hpp

@@ -42,9 +42,6 @@ class BCN_API chaser
 public:
     enum class chase
     {
-        /// Initialize chaser state ({}).
-        start,
-
         /// A new strong branch exists (strong height_t).
         /// Issued by 'header' and handled by 'check'.
         header,
@@ -86,8 +83,8 @@ class BCN_API chaser
     typedef database::query<store> query;
     DELETE_COPY_MOVE(chaser);
 
-    // TODO: public method to check/store a block.
-    // TODO: not stranded, thread safe, and posts checked event.
+    /// Synchronously subscribe to notify and asynchronously initialize state.
+    virtual bool start() NOEXCEPT = 0;
 
 protected:
     chaser(full_node& node) NOEXCEPT;
@@ -102,8 +99,8 @@ class BCN_API chaser
     /// True if the current thread is on the chaser strand.
     bool stranded() const NOEXCEPT;
 
-    /// Subscribe to chaser events (must be non-virtual).
-    code subscribe(event_handler&& handler) NOEXCEPT;
+    /// Subscribe to chaser events.
+    bool subscribe(event_handler&& handler) NOEXCEPT;
 
     /// Set chaser event (does not require network strand).
     void notify(const code& ec, chase event_, link value) NOEXCEPT;

include/bitcoin/node/chasers/chaser_candidate.hpp

@@ -19,6 +19,7 @@
 #ifndef LIBBITCOIN_NODE_CHASERS_CHASER_CANDIDATE_HPP
 #define LIBBITCOIN_NODE_CHASERS_CHASER_CANDIDATE_HPP
 
+#include <functional>
 #include <bitcoin/network.hpp>
 #include <bitcoin/node/define.hpp>
 #include <bitcoin/node/chasers/chaser.hpp>
@@ -30,17 +31,19 @@ class full_node;
 
 /// Construct candidate blocks upon modification of the transaction DAG.
 class BCN_API chaser_candidate
-  : public chaser, protected network::tracker<chaser_candidate>
+  : public chaser
 {
 public:
-    typedef std::unique_ptr<chaser_candidate> uptr;
-
     chaser_candidate(full_node& node) NOEXCEPT;
 
+    virtual bool start() NOEXCEPT;
+
+protected:
+    virtual void handle_transaction(transaction_t value) NOEXCEPT;
+    virtual void handle_event(const code& ec, chase event_,
+        link value) NOEXCEPT;
+
 private:
-    void handle_start() NOEXCEPT;
-    void handle_transaction() NOEXCEPT;
-    void handle_event(const code& ec, chase event_, link value) NOEXCEPT;
     void do_handle_event(const code& ec, chase event_, link value) NOEXCEPT;
 };
 

include/bitcoin/node/chasers/chaser_check.hpp

@@ -19,6 +19,7 @@
 #ifndef LIBBITCOIN_NODE_CHASERS_CHASER_CHECK_HPP
 #define LIBBITCOIN_NODE_CHASERS_CHASER_CHECK_HPP
 
+#include <functional>
 #include <bitcoin/network.hpp>
 #include <bitcoin/node/define.hpp>
 #include <bitcoin/node/chasers/chaser.hpp>
@@ -30,17 +31,15 @@ class full_node;
 
 /// Chase down blocks for the candidate header chain.
 class BCN_API chaser_check
-  : public chaser, protected network::tracker<chaser_check>
+  : public chaser
 {
 public:
-    typedef std::unique_ptr<chaser_check> uptr;
-
     chaser_check(full_node& node) NOEXCEPT;
 
-    void checked(const system::chain::block::cptr& block) NOEXCEPT;
+    virtual bool start() NOEXCEPT;
+    virtual void checked(const system::chain::block::cptr& block) NOEXCEPT;
 
 protected:
-    virtual void handle_start() NOEXCEPT;
     virtual void handle_header(height_t branch_point) NOEXCEPT;
     virtual void handle_event(const code& ec, chase event_,
         link value) NOEXCEPT;

include/bitcoin/node/chasers/chaser_confirm.hpp

@@ -19,6 +19,7 @@
 #ifndef LIBBITCOIN_NODE_CHASERS_CHASER_CONFIRM_HPP
 #define LIBBITCOIN_NODE_CHASERS_CHASER_CONFIRM_HPP
 
+#include <functional>
 #include <bitcoin/network.hpp>
 #include <bitcoin/node/define.hpp>
 #include <bitcoin/node/chasers/chaser.hpp>
@@ -30,17 +31,19 @@ class full_node;
 
 /// Chase down valid blocks for confirmation.
 class BCN_API chaser_confirm
-  : public chaser, protected network::tracker<chaser_confirm>
+  : public chaser
 {
 public:
-    typedef std::unique_ptr<chaser_confirm> uptr;
-
     chaser_confirm(full_node& node) NOEXCEPT;
 
+    virtual bool start() NOEXCEPT;
+
+protected:
+    virtual void handle_connected(header_t block) NOEXCEPT;
+    virtual void handle_event(const code& ec, chase event_,
+        link value) NOEXCEPT;
+
 private:
-    void handle_start() NOEXCEPT;
-    void handle_connected() NOEXCEPT;
-    void handle_event(const code& ec, chase event_, link value) NOEXCEPT;
     void do_handle_event(const code& ec, chase event_, link value) NOEXCEPT;
 };
 

include/bitcoin/node/chasers/chaser_connect.hpp

@@ -19,6 +19,7 @@
 #ifndef LIBBITCOIN_NODE_CHASERS_CHASER_CONNECT_HPP
 #define LIBBITCOIN_NODE_CHASERS_CHASER_CONNECT_HPP
 
+#include <functional>
 #include <bitcoin/network.hpp>
 #include <bitcoin/node/define.hpp>
 #include <bitcoin/node/chasers/chaser.hpp>
@@ -30,17 +31,19 @@ class full_node;
 
 /// Chase down blocks in the the candidate header chain for validation.
 class BCN_API chaser_connect
-  : public chaser, protected network::tracker<chaser_connect>
+  : public chaser
 {
 public:
-    typedef std::unique_ptr<chaser_connect> uptr;
-
     chaser_connect(full_node& node) NOEXCEPT;
 
+    virtual bool start() NOEXCEPT;
+
+protected:
+    virtual void handle_checked(header_t block) NOEXCEPT;
+    virtual void handle_event(const code& ec, chase event_,
+        link value) NOEXCEPT;
+
 private:
-    void handle_start() NOEXCEPT;
-    void handle_checked() NOEXCEPT;
-    void handle_event(const code& ec, chase event_, link value) NOEXCEPT;
     void do_handle_event(const code& ec, chase event_, link value) NOEXCEPT;
 };
 

include/bitcoin/node/chasers/chaser_header.hpp

@@ -19,6 +19,7 @@
 #ifndef LIBBITCOIN_NODE_CHASERS_CHASER_HEADER_HPP
 #define LIBBITCOIN_NODE_CHASERS_CHASER_HEADER_HPP
 
+#include <functional>
 #include <unordered_map>
 #include <bitcoin/database.hpp>
 #include <bitcoin/network.hpp>
@@ -34,24 +35,23 @@ class full_node;
 /// Weak branches are retained in a hash table unless already store populated.
 /// Strong branches reorganize the candidate chain and fire the 'header' event.
 class BCN_API chaser_header
-  : public chaser, protected network::tracker<chaser_header>
+  : public chaser
 {
 public:
-    typedef std::unique_ptr<chaser_header> uptr;
-
     chaser_header(full_node& node) NOEXCEPT;
 
+    virtual bool start() NOEXCEPT;
+
     /// Organize the next header in sequence, relative to caller's peer.
     /// Causes a fault/stop if preceding headers have not been stored.
     /// Caller must validate the header and provide context.
-    void organize(const system::chain::header::cptr& header,
+    virtual void organize(const system::chain::header::cptr& header,
         system::chain::context&& context) NOEXCEPT;
 
 protected:
     typedef std::vector<database::header_link> header_links;
 
     /// Handlers.
-    virtual void handle_start() NOEXCEPT;
     virtual void handle_event(const code& ec, chase event_,
         link value) NOEXCEPT;
 

include/bitcoin/node/chasers/chaser_transaction.hpp

@@ -19,6 +19,7 @@
 #ifndef LIBBITCOIN_NODE_CHASERS_CHASER_TRANSACTION_HPP
 #define LIBBITCOIN_NODE_CHASERS_CHASER_TRANSACTION_HPP
 
+#include <functional>
 #include <bitcoin/network.hpp>
 #include <bitcoin/node/define.hpp>
 #include <bitcoin/node/chasers/chaser.hpp>
@@ -30,19 +31,20 @@ class full_node;
 
 /// Chase down unconfirmed transactions.
 class BCN_API chaser_transaction
-  : public chaser, protected network::tracker<chaser_transaction>
+  : public chaser
 {
 public:
-    typedef std::unique_ptr<chaser_transaction> uptr;
-
     chaser_transaction(full_node& node) NOEXCEPT;
 
-    void store(const system::chain::transaction::cptr& block) NOEXCEPT;
+    virtual bool start() NOEXCEPT;
+    virtual void store(const system::chain::transaction::cptr& block) NOEXCEPT;
+
+protected:
+    virtual void handle_confirmed() NOEXCEPT;
+    virtual void handle_event(const code& ec, chase event_,
+        link value) NOEXCEPT;
 
 private:
-    void handle_start() NOEXCEPT;
-    void handle_confirmed() NOEXCEPT;
-    void handle_event(const code& ec, chase event_, link value) NOEXCEPT;
     void do_handle_event(const code& ec, chase event_, link value) NOEXCEPT;
     void do_store(const system::chain::transaction::cptr& header) NOEXCEPT;
 };

include/bitcoin/node/full_node.hpp

@@ -44,6 +44,8 @@ class BCN_API full_node
     full_node(query& query, const configuration& configuration,
         const network::logger& log) NOEXCEPT;
 
+    ~full_node() NOEXCEPT;
+
     /// Sequences.
     /// -----------------------------------------------------------------------
 
@@ -79,13 +81,6 @@ class BCN_API full_node
     chaser::event_subscriber& event_subscriber() NOEXCEPT;
 
 protected:
-
-    /// Chasers configuration.
-    /// -----------------------------------------------------------------------
-    virtual code create_chasers() NOEXCEPT;
-    virtual void stop_chasers() NOEXCEPT;
-    virtual void delete_chasers() NOEXCEPT;
-
     /// Session attachments.
     /// -----------------------------------------------------------------------
     network::session_manual::ptr attach_manual_session() NOEXCEPT override;
@@ -105,12 +100,12 @@ class BCN_API full_node
 
     // These are protected by strand.
     chaser::event_subscriber event_subscriber_;
-    chaser_header::uptr chaser_header_{};
-    chaser_check::uptr chaser_check_{};
-    chaser_connect::uptr chaser_connect_{};
-    chaser_confirm::uptr chaser_confirm_{};
-    chaser_transaction::uptr chaser_transaction_{};
-    chaser_candidate::uptr chaser_candidate_{};
+    chaser_header chaser_header_;
+    chaser_check chaser_check_;
+    chaser_connect chaser_connect_;
+    chaser_confirm chaser_confirm_;
+    chaser_transaction chaser_transaction_;
+    chaser_candidate chaser_candidate_;
 };
 
 } // namespace node

src/chasers/chaser.cpp

@@ -58,12 +58,18 @@ bool chaser::stranded() const NOEXCEPT
     return strand_.running_in_this_thread();
 }
 
-// Must be non-virtual for constructor invoke.
-// Requires network strand (call from node start).
-code chaser::subscribe(event_handler&& handler) NOEXCEPT
+bool chaser::subscribe(event_handler&& handler) NOEXCEPT
 {
     BC_ASSERT_MSG(node_.stranded(), "chaser");
-    return subscriber_.subscribe(std::move(handler));
+    const auto ec = subscriber_.subscribe(std::move(handler));
+
+    if (ec)
+    {
+        LOGF("Chaser subscribe fault, " << ec.message());
+        return false;
+    }
+
+    return true;
 }
 
 // Posts to network strand (call from chaser strands).

src/chasers/chaser_candidate.cpp

@@ -19,6 +19,7 @@
 #include <bitcoin/node/chasers/chaser_candidate.hpp>
 
 #include <functional>
+#include <variant>
 #include <bitcoin/network.hpp>
 #include <bitcoin/node/error.hpp>
 #include <bitcoin/node/full_node.hpp>
@@ -31,11 +32,10 @@ using namespace std::placeholders;
 
 BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
 
+// Requires subscriber_ protection (call from node construct or node.strand).
 chaser_candidate::chaser_candidate(full_node& node) NOEXCEPT
-  : chaser(node),
-    tracker<chaser_candidate>(node.log)
+  : chaser(node)
 {
-    subscribe(std::bind(&chaser_candidate::handle_event, this, _1, _2, _3));
 }
 
 void chaser_candidate::handle_event(const code& ec, chase event_,
@@ -46,7 +46,7 @@ void chaser_candidate::handle_event(const code& ec, chase event_,
 }
 
 void chaser_candidate::do_handle_event(const code& ec, chase event_,
-    link) NOEXCEPT
+    link value) NOEXCEPT
 {
     BC_ASSERT_MSG(stranded(), "chaser_candidate");
 
@@ -55,14 +55,10 @@ void chaser_candidate::do_handle_event(const code& ec, chase event_,
 
     switch (event_)
     {
-        case chase::start:
-        {
-            handle_start();
-            break;
-        }
         case chase::transaction:
         {
-            handle_transaction();
+            BC_ASSERT(std::holds_alternative<transaction_t>(value));
+            handle_transaction(std::get<transaction_t>(value));
             break;
         }
         default:
@@ -71,15 +67,17 @@ void chaser_candidate::do_handle_event(const code& ec, chase event_,
 }
 
 // TODO: initialize candidate state.
-void chaser_candidate::handle_start() NOEXCEPT
+bool chaser_candidate::start() NOEXCEPT
 {
-    BC_ASSERT_MSG(stranded(), "chaser_candidate");
+    return subscribe(std::bind(&chaser_candidate::handle_event,
+        this, _1, _2, _3));
 }
 
 // TODO: handle transaction graph change (may issue 'candidate').
-void chaser_candidate::handle_transaction() NOEXCEPT
+void chaser_candidate::handle_transaction(transaction_t tx) NOEXCEPT
 {
     BC_ASSERT_MSG(stranded(), "chaser_candidate");
+    LOGN("Handle transaction pool updated (" << tx << ").");
 }
 
 BC_POP_WARNING()