Add disabled retainer allocated parameter.

include/bitcoin/system/chain/block.hpp

@@ -112,8 +112,9 @@ class BC_API block
     /// Reference used to avoid copy, sets cache if not set (not thread safe).
     const hash_digest& get_hash() const NOEXCEPT;
 
-    /// Set memory retention mutex.
+    /// Set/get memory retainer.
     void set_retainer(retainer::ptr&& retainer) const NOEXCEPT;
+    const retainer::ptr& get_retainer() const NOEXCEPT;
 
     /// Identity.
     /// -----------------------------------------------------------------------

include/bitcoin/system/retainer.hpp

@@ -25,6 +25,8 @@
 
 namespace libbitcoin {
 
+BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
+
 /// Shared lock object to inform allocator that memory may be freed.
 class BC_API retainer final
 {
@@ -33,23 +35,29 @@ class BC_API retainer final
 
     DELETE_COPY_MOVE_DESTRUCT(retainer);
 
-    retainer() NOEXCEPT
-      : shared_lock_{}
+    inline retainer() NOEXCEPT
+      : /*allocation_{},*/ shared_lock_{}
     {
     }
 
-    BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
-    retainer(std::shared_mutex& mutex) NOEXCEPT
-      : shared_lock_(mutex)
+    inline retainer(std::shared_mutex& mutex, size_t=0) NOEXCEPT
+      : /*allocation_{ allocation },*/ shared_lock_{ mutex }
     {
     }
-    BC_POP_WARNING()
+
+    inline size_t allocation() const NOEXCEPT
+    {
+        return {};//// allocation_;
+    }
 
 private:
-    // This is thread safe.
+    // These are thread safe.
+    ////size_t allocation_;
     std::shared_lock<std::shared_mutex> shared_lock_;
 };
 
+BC_POP_WARNING()
+
 } // namespace libbitcoin
 
 #endif

src/chain/block.cpp

@@ -167,6 +167,11 @@ void block::set_retainer(retainer::ptr&& retainer) const NOEXCEPT
     retainer_ = std::move(retainer);
 }
 
+const retainer::ptr& block::get_retainer() const NOEXCEPT
+{
+    return retainer_;
+}
+
 // Serialization.
 // ----------------------------------------------------------------------------