Clean up chaser start/stop and error handling.

include/bitcoin/node/chasers/chaser.hpp

@@ -84,7 +84,7 @@ class BCN_API chaser
     DELETE_COPY_MOVE(chaser);
 
     /// Synchronously subscribe to notify and asynchronously initialize state.
-    virtual bool start() NOEXCEPT = 0;
+    virtual code start() NOEXCEPT = 0;
 
 protected:
     chaser(full_node& node) NOEXCEPT;
@@ -99,13 +99,16 @@ class BCN_API chaser
     /// True if the current thread is on the chaser strand.
     bool stranded() const NOEXCEPT;
 
+    /// True if the current thread is on the node strand.
+    bool node_stranded() const NOEXCEPT;
+
     /// Subscribe to chaser events.
-    bool subscribe(event_handler&& handler) NOEXCEPT;
+    code subscribe(event_handler&& handler) NOEXCEPT;
 
     /// Set chaser event (does not require network strand).
     void notify(const code& ec, chase event_, link value) NOEXCEPT;
 
-    /// Close the node.
+    /// Close the node in case of failure.
     void stop(const code& ec) NOEXCEPT;
 
 private:

include/bitcoin/node/chasers/chaser_candidate.hpp

@@ -36,7 +36,7 @@ class BCN_API chaser_candidate
 public:
     chaser_candidate(full_node& node) NOEXCEPT;
 
-    virtual bool start() NOEXCEPT;
+    virtual code start() NOEXCEPT;
 
 protected:
     virtual void handle_transaction(transaction_t value) NOEXCEPT;

include/bitcoin/node/chasers/chaser_check.hpp

@@ -36,7 +36,7 @@ class BCN_API chaser_check
 public:
     chaser_check(full_node& node) NOEXCEPT;
 
-    virtual bool start() NOEXCEPT;
+    virtual code start() NOEXCEPT;
     virtual void checked(const system::chain::block::cptr& block) NOEXCEPT;
 
 protected:

include/bitcoin/node/chasers/chaser_confirm.hpp

@@ -36,7 +36,7 @@ class BCN_API chaser_confirm
 public:
     chaser_confirm(full_node& node) NOEXCEPT;
 
-    virtual bool start() NOEXCEPT;
+    virtual code start() NOEXCEPT;
 
 protected:
     virtual void handle_connected(header_t block) NOEXCEPT;

include/bitcoin/node/chasers/chaser_connect.hpp

@@ -36,7 +36,7 @@ class BCN_API chaser_connect
 public:
     chaser_connect(full_node& node) NOEXCEPT;
 
-    virtual bool start() NOEXCEPT;
+    virtual code start() NOEXCEPT;
 
 protected:
     virtual void handle_checked(header_t block) NOEXCEPT;

include/bitcoin/node/chasers/chaser_header.hpp

@@ -19,7 +19,6 @@
 #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>
@@ -40,7 +39,7 @@ class BCN_API chaser_header
 public:
     chaser_header(full_node& node) NOEXCEPT;
 
-    virtual bool start() NOEXCEPT;
+    virtual code start() NOEXCEPT;
 
     /// Organize the next header in sequence, relative to caller's peer.
     /// Causes a fault/stop if preceding headers have not been stored.

include/bitcoin/node/chasers/chaser_transaction.hpp

@@ -36,7 +36,7 @@ class BCN_API chaser_transaction
 public:
     chaser_transaction(full_node& node) NOEXCEPT;
 
-    virtual bool start() NOEXCEPT;
+    code start() NOEXCEPT override;
     virtual void store(const system::chain::transaction::cptr& block) NOEXCEPT;
 
 protected:

src/chasers/chaser.cpp

@@ -58,18 +58,15 @@ bool chaser::stranded() const NOEXCEPT
     return strand_.running_in_this_thread();
 }
 
-bool chaser::subscribe(event_handler&& handler) NOEXCEPT
+bool chaser::node_stranded() const NOEXCEPT
 {
-    BC_ASSERT_MSG(node_.stranded(), "chaser");
-    const auto ec = subscriber_.subscribe(std::move(handler));
-
-    if (ec)
-    {
-        LOGF("Chaser subscribe fault, " << ec.message());
-        return false;
-    }
+    return node_.stranded();
+}
 
-    return true;
+code chaser::subscribe(event_handler&& handler) NOEXCEPT
+{
+    BC_ASSERT_MSG(node_stranded(), "chaser");
+    return subscriber_.subscribe(std::move(handler));
 }
 
 // Posts to network strand (call from chaser strands).
@@ -82,13 +79,13 @@ void chaser::notify(const code& ec, chase event_, link value) NOEXCEPT
 // Executed on network strand (handler should bounce to chaser strand).
 void chaser::do_notify(const code& ec, chase event_, link value) NOEXCEPT
 {
-    BC_ASSERT_MSG(node_.stranded(), "chaser");
+    BC_ASSERT_MSG(node_stranded(), "chaser");
     subscriber_.notify(ec, event_, value);
 }
 
-void chaser::stop(const code&) NOEXCEPT
+void chaser::stop(const code& ec) NOEXCEPT
 {
-    ////LOGF("Chaser fault, " << ec.message());
+    LOGF("Chaser fault, " << ec.message());
     node_.close();
 }
 

src/chasers/chaser_candidate.cpp

@@ -38,6 +38,14 @@ chaser_candidate::chaser_candidate(full_node& node) NOEXCEPT
 {
 }
 
+// TODO: initialize candidate state.
+code chaser_candidate::start() NOEXCEPT
+{
+    BC_ASSERT_MSG(node_stranded(), "chaser_check");
+    return subscribe(std::bind(&chaser_candidate::handle_event,
+        this, _1, _2, _3));
+}
+
 void chaser_candidate::handle_event(const code& ec, chase event_,
     link value) NOEXCEPT
 {
@@ -66,13 +74,6 @@ void chaser_candidate::do_handle_event(const code& ec, chase event_,
     }
 }
 
-// TODO: initialize candidate state.
-bool chaser_candidate::start() NOEXCEPT
-{
-    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(transaction_t tx) NOEXCEPT
 {

src/chasers/chaser_check.cpp

@@ -39,6 +39,16 @@ chaser_check::chaser_check(full_node& node) NOEXCEPT
 {
 }
 
+// TODO: initialize check state.
+code chaser_check::start() NOEXCEPT
+{
+    BC_ASSERT_MSG(node_stranded(), "chaser_check");
+
+    // get_all_unassociated_above(0)
+    return subscribe(std::bind(&chaser_check::handle_event,
+        this, _1, _2, _3));
+}
+
 void chaser_check::handle_event(const code& ec, chase event_,
     link value) NOEXCEPT
 {
@@ -67,14 +77,6 @@ void chaser_check::do_handle_event(const code& ec, chase event_,
     }
 }
 
-// TODO: initialize check state.
-bool chaser_check::start() NOEXCEPT
-{
-    // get_all_unassociated_above(0)
-    return subscribe(std::bind(&chaser_check::handle_event,
-        this, _1, _2, _3));
-}
-
 // TODO: handle the new strong branch (may issue 'checked').
 void chaser_check::handle_header(height_t branch_point) NOEXCEPT
 {

src/chasers/chaser_confirm.cpp

@@ -37,6 +37,14 @@ chaser_confirm::chaser_confirm(full_node& node) NOEXCEPT
 {
 }
 
+// TODO: initialize confirm state.
+code chaser_confirm::start() NOEXCEPT
+{
+    BC_ASSERT_MSG(node_stranded(), "chaser_confirm");
+    return subscribe(std::bind(&chaser_confirm::handle_event,
+        this, _1, _2, _3));
+}
+
 void chaser_confirm::handle_event(const code& ec, chase event_,
     link value) NOEXCEPT
 {
@@ -65,13 +73,6 @@ void chaser_confirm::do_handle_event(const code& ec, chase event_,
     }
 }
 
-// TODO: initialize confirm state.
-bool chaser_confirm::start() NOEXCEPT
-{
-    return subscribe(std::bind(&chaser_confirm::handle_event,
-        this, _1, _2, _3));
-}
-
 // TODO: handle new strong connected branch (may issue 'confirmed').
 void chaser_confirm::handle_connected(header_t block) NOEXCEPT
 {

src/chasers/chaser_connect.cpp

@@ -37,6 +37,14 @@ chaser_connect::chaser_connect(full_node& node) NOEXCEPT
 {
 }
 
+// TODO: initialize connect state.
+code chaser_connect::start() NOEXCEPT
+{
+    BC_ASSERT_MSG(node_stranded(), "chaser_connect");
+    return subscribe(std::bind(&chaser_connect::handle_event,
+        this, _1, _2, _3));
+}
+
 void chaser_connect::handle_event(const code& ec, chase event_,
     link value) NOEXCEPT
 {
@@ -65,13 +73,6 @@ void chaser_connect::do_handle_event(const code& ec, chase event_,
     }
 }
 
-// TODO: initialize connect state.
-bool chaser_connect::start() NOEXCEPT
-{
-    return subscribe(std::bind(&chaser_connect::handle_event,
-        this, _1, _2, _3));
-}
-
 // TODO: handle the new checked blocks (may issue 'connected').
 void chaser_connect::handle_checked(header_t block) NOEXCEPT
 {

src/chasers/chaser_header.cpp

@@ -34,14 +34,21 @@ using namespace std::placeholders;
 
 BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
 
-// Requires subscriber_ protection (call from node construct or node.strand).
 chaser_header::chaser_header(full_node& node) NOEXCEPT
   : chaser(node),
     currency_window_(node.node_settings().currency_window()),
     use_currency_window_(currency_window_ != wall_clock::duration::zero())
 {
 }
 
+// protected
+code chaser_header::start() NOEXCEPT
+{
+    BC_ASSERT_MSG(node_stranded(), "chaser_header");
+    return subscribe(std::bind(&chaser_header::handle_event,
+        this, _1, _2, _3));
+}
+
 // protected
 void chaser_header::handle_event(const code& ec, chase event_,
     link value) NOEXCEPT
@@ -57,13 +64,6 @@ void chaser_header::do_handle_event(const code&, chase, link) NOEXCEPT
     BC_ASSERT_MSG(stranded(), "chaser_header");
 }
 
-// protected
-bool chaser_header::start() NOEXCEPT
-{
-    return subscribe(std::bind(&chaser_header::handle_event,
-        this, _1, _2, _3));
-}
-
 void chaser_header::organize(const chain::header::cptr& header,
     chain::context&& context) NOEXCEPT
 {
@@ -258,6 +258,7 @@ bool chaser_header::get_is_strong(bool& strong, const uint256_t& work,
     return true;
 }
 
+// protected
 void chaser_header::save(const chain::header::cptr& header,
     const chain::context& context) NOEXCEPT
 {

src/chasers/chaser_transaction.cpp

@@ -38,6 +38,14 @@ chaser_transaction::chaser_transaction(full_node& node) NOEXCEPT
 {
 }
 
+// TODO: initialize tx graph from store, log and stop on error.
+code chaser_transaction::start() NOEXCEPT
+{
+    BC_ASSERT_MSG(node_stranded(), "chaser_transaction");
+    return subscribe(std::bind(&chaser_transaction::handle_event,
+        this, _1, _2, _3));
+}
+
 void chaser_transaction::handle_event(const code& ec, chase event_,
     link value) NOEXCEPT
 {
@@ -65,13 +73,6 @@ void chaser_transaction::do_handle_event(const code& ec, chase event_,
     }
 }
 
-// TODO: initialize tx graph from store, log and stop on error.
-bool chaser_transaction::start() NOEXCEPT
-{
-    return subscribe(std::bind(&chaser_transaction::handle_event,
-        this, _1, _2, _3));
-}
-
 // TODO: handle the new confirmed blocks (may issue 'transaction').
 void chaser_transaction::handle_confirmed() NOEXCEPT
 {

src/full_node.cpp

@@ -72,15 +72,16 @@ void full_node::start(result_handler&& handler) NOEXCEPT
 void full_node::do_start(const result_handler& handler) NOEXCEPT
 {
     BC_ASSERT_MSG(stranded(), "full_node");
-
-    if (!chaser_header_.start() ||
-        !chaser_check_.start() ||
-        !chaser_connect_.start() ||
-        !chaser_confirm_.start() ||
-        !chaser_transaction_.start() ||
-        !chaser_candidate_.start())
+    code ec;
+
+    if (((ec = chaser_header_.start())) ||
+        ((ec = chaser_check_.start())) ||
+        ((ec = chaser_connect_.start())) ||
+        ((ec = chaser_confirm_.start())) ||
+        ((ec = chaser_transaction_.start())) ||
+        ((ec = chaser_candidate_.start())))
     {
-        handler(error::unknown);
+        handler(ec);
         return;
     }