Initial functional implementation of competitive header sync.

include/bitcoin/node/chasers/chaser.hpp

@@ -104,7 +104,7 @@ class BCN_API chaser
     void notify(const code& ec, chase event_, link value) NOEXCEPT;
 
     /// Close the node.
-    void close(const code& ec) NOEXCEPT;
+    void stop(const code& ec) NOEXCEPT;
 
 private:
     void do_notify(const code& ec, chase event_, link value) NOEXCEPT;

include/bitcoin/node/chasers/chaser_header.hpp

@@ -19,6 +19,8 @@
 #ifndef LIBBITCOIN_NODE_CHASERS_CHASER_HEADER_HPP
 #define LIBBITCOIN_NODE_CHASERS_CHASER_HEADER_HPP
 
+#include <unordered_map>
+#include <bitcoin/database.hpp>
 #include <bitcoin/network.hpp>
 #include <bitcoin/node/define.hpp>
 #include <bitcoin/node/chasers/chaser.hpp>
@@ -29,6 +31,8 @@ namespace node {
 class full_node;
 
 /// Chase down stronger header branches for the candidate chain.
+/// 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>
 {
@@ -37,20 +41,61 @@ class BCN_API chaser_header
 
     chaser_header(full_node& node) NOEXCEPT;
 
-    void store(const system::chain::header::cptr& header) 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,
+        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;
+
+    /// Sum of work from header to branch point (excluded).
+    virtual bool get_branch_work(uint256_t& work, size_t& point,
+        system::hashes& tree_branch, header_links& store_branch,
+        const system::chain::header& header) const NOEXCEPT;
+
+    /// Strong if new branch work exceeds candidate work.
+    /// Also obtains branch point for work summation termination.
+    /// Also obtains ordered branch identifiers for subsequent reorg.
+    virtual bool get_is_strong(bool& strong, const uint256_t& work,
+        size_t point) const NOEXCEPT;
+
+    /// Header timestamp is within configured span from current time.
+    virtual bool is_current(const system::chain::header& header) const NOEXCEPT;
+
+    /// Save header to tree with validation context.
+    virtual void save(const system::chain::header::cptr& header,
+        const system::chain::context& context) NOEXCEPT;
+
+    /// Store header to database and push to top of candidate chain.
+    virtual database::header_link push(
+        const system::chain::header::cptr& header,
+        const system::chain::context& context) const NOEXCEPT;
+
+    /// Move tree header to database and push to top of candidate chain.
+    virtual bool push(const system::hash_digest& key) NOEXCEPT;
 
 private:
-    bool is_current(const system::chain::header& header) const NOEXCEPT;
-    bool is_strong(const system::chain::header& header) const NOEXCEPT;
+    struct proposed_header
+    {
+        database::context context;
+        system::chain::header::cptr header;
+    };
 
-    void handle_start() 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::header::cptr& header) NOEXCEPT;
+    void do_organize(const system::chain::header::cptr& header,
+        const system::chain::context& context) NOEXCEPT;
 
     // These are protected by strand.
+    std::unordered_map<system::hash_digest, proposed_header> tree_{};
     const network::wall_clock::duration currency_window_;
-    std::vector<system::chain::header::cptr> chain_{};
+    const bool use_currency_window_;
 };
 
 } // namespace node

include/bitcoin/node/error.hpp

@@ -41,14 +41,15 @@ enum error_t : uint8_t
     unexpected_event,
 
     // database
+    store_integrity,
     store_uninitialized,
 
     // network
     slow_channel,
     stalled_channel,
 
     // blockchain
-    orphan_block,
+    orphan_header,
     insufficient_work,
     duplicate_block
 };

include/bitcoin/node/full_node.hpp

@@ -56,6 +56,13 @@ class BCN_API full_node
     /// Close the node.
     void close() NOEXCEPT override;
 
+    /// Chasers.
+    /// -----------------------------------------------------------------------
+
+    /// Organize a validated header, failures stop the node.
+    virtual void organize(const system::chain::header::cptr& header,
+        system::chain::context&& context) NOEXCEPT;
+
     /// Properties.
     /// -----------------------------------------------------------------------
 

include/bitcoin/node/protocols/protocol.hpp

@@ -49,10 +49,14 @@ class BCN_API protocol
 
     virtual ~protocol() NOEXCEPT;
 
-    /// Report performance, false directs self-terminate.
+    /// Report performance, handler may direct self-terminate.
     virtual void performance(uint64_t channel, uint64_t speed,
         network::result_handler&& handler) const NOEXCEPT;
 
+    /// Organize a validated header, failures stop the node.
+    virtual void organize(const system::chain::header::cptr& header,
+        system::chain::context&& context) NOEXCEPT;
+
     /// Configuration settings for all libraries.
     const configuration& config() const NOEXCEPT;
 

include/bitcoin/node/sessions/attach.hpp

@@ -61,21 +61,21 @@ class attach
         Session::attach_protocols(channel);
 
         auto& self = *this;
-        ////const auto version = channel->negotiated_version();
-        ////
-        ////if (version >= network::messages::level::bip130)
-        ////{
-        ////    channel->attach<protocol_header_in_70012>(self)->start();
-        ////    channel->attach<protocol_header_out_70012>(self)->start();
-        ////}
-        ////else if (version >= network::messages::level::headers_protocol)
-        ////{
-        ////    channel->attach<protocol_header_in_31800>(self)->start();
-        ////    channel->attach<protocol_header_out_31800>(self)->start();
-        ////}
+        const auto version = channel->negotiated_version();
+
+        if (version >= network::messages::level::bip130)
+        {
+            channel->attach<protocol_header_in_70012>(self)->start();
+            channel->attach<protocol_header_out_70012>(self)->start();
+        }
+        else if (version >= network::messages::level::headers_protocol)
+        {
+            channel->attach<protocol_header_in_31800>(self)->start();
+            channel->attach<protocol_header_out_31800>(self)->start();
+        }
 
-        constexpr auto performance = false;
-        channel->attach<protocol_block_in>(self, performance)->start();
+        ////constexpr auto performance = false;
+        ////channel->attach<protocol_block_in>(self, performance)->start();
         ////channel->attach<protocol_block_out>(self)->start();
         ////channel->attach<protocol_transaction_in>(self)->start();
         ////channel->attach<protocol_transaction_out>(self)->start();

include/bitcoin/node/sessions/session.hpp

@@ -36,6 +36,10 @@ class BCN_API session
     virtual void performance(uint64_t channel, uint64_t speed,
         network::result_handler&& handler) NOEXCEPT;
 
+    /// Organize a validated header, failures stop the node.
+    virtual void organize(const system::chain::header::cptr& header,
+        system::chain::context&& context) NOEXCEPT;
+
     /// Configuration settings for all libraries.
     const configuration& config() const NOEXCEPT;
 

src/chasers/chaser.cpp

@@ -80,9 +80,9 @@ void chaser::do_notify(const code& ec, chase event_, link value) NOEXCEPT
     subscriber_.notify(ec, event_, value);
 }
 
-void chaser::close(const code& ec) NOEXCEPT
+void chaser::stop(const code&) NOEXCEPT
 {
-    LOGF("Chaser fault, " << ec.message());
+    ////LOGF("Chaser fault, " << ec.message());
     node_.close();
 }