Style, comments, throw on over-requested block arenas.

include/bitcoin/node/block_memory.hpp

@@ -36,9 +36,8 @@ class BCN_API block_memory final
 public:
     DELETE_COPY_MOVE_DESTRUCT(block_memory);
 
-    /// Store the size for each thread's arena initilization.
     /// Default allocate each arena to preclude allcation and locking.
-    block_memory(size_t size, size_t threads) NOEXCEPT;
+    block_memory(size_t bytes, size_t threads) NOEXCEPT;
 
     /// Each thread obtains an arena of the same size.
     arena* get_arena() NOEXCEPT override;
@@ -47,13 +46,13 @@ class BCN_API block_memory final
     retainer::ptr get_retainer() NOEXCEPT override;
 
 protected:
-    block_arena* get_block_arena() NOEXCEPT;
+    block_arena* get_block_arena() THROWS;
 
 private:
-    // These are thread safe.
+    // This is thread safe.
     std::atomic_size_t count_;
 
-    // This is protected by thread_local member.
+    // This is protected by constructor init and thread_local indexation.
     std::vector<block_arena> arenas_;
 };
 

src/block_memory.cpp

@@ -25,17 +25,19 @@
 namespace libbitcoin {
 namespace node {
 
-block_memory::block_memory(size_t size, size_t threads) NOEXCEPT
+block_memory::block_memory(size_t bytes, size_t threads) NOEXCEPT
   : count_{}, arenas_{}
 {
     arenas_.reserve(threads);
     for (auto index = zero; index < threads; ++index)
-        arenas_.emplace_back(size);
+        arenas_.emplace_back(bytes);
 }
 
 arena* block_memory::get_arena() NOEXCEPT
 {
+    BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
     return get_block_arena();
+    BC_POP_WARNING()
 }
 
 retainer::ptr block_memory::get_retainer() NOEXCEPT
@@ -47,12 +49,13 @@ retainer::ptr block_memory::get_retainer() NOEXCEPT
 
 // protected
 
-block_arena* block_memory::get_block_arena() NOEXCEPT
+block_arena* block_memory::get_block_arena() THROWS
 {
     static thread_local auto index = count_.fetch_add(one);
 
+    // More threads are requesting an arena than specified at construct.
     if (index >= arenas_.size())
-        return nullptr;
+        throw allocation_exception();
 
     return &arenas_.at(index);
 }