From 8ed1a01aedcaffdc19b746a37f0e559c9bf26aad Mon Sep 17 00:00:00 2001
From: evoskuil <eric@voskuil.org>
Date: Wed, 21 Aug 2024 14:19:54 -0400
Subject: [PATCH] Enable block deserialization disable via config.

---
 include/bitcoin/node/block_memory.hpp |  8 +++-----
 src/block_memory.cpp                  | 27 ++++++++-------------------
 src/parser.cpp                        |  2 +-
 3 files changed, 12 insertions(+), 25 deletions(-)

diff --git a/include/bitcoin/node/block_memory.hpp b/include/bitcoin/node/block_memory.hpp
index 98178b58..310d6e43 100644
--- a/include/bitcoin/node/block_memory.hpp
+++ b/include/bitcoin/node/block_memory.hpp
@@ -35,20 +35,18 @@ class BCN_API block_memory final
     DELETE_COPY_MOVE_DESTRUCT(block_memory);
 
     /// Per thread multiple of wire size for each linear allocation chunk.
+    /// Returns default_arena if multiple is zero or threads exceeded.
     block_memory(size_t multiple, size_t threads) NOEXCEPT;
 
     /// Each thread obtains an arena.
     arena* get_arena() NOEXCEPT override;
 
-protected:
-    block_arena* get_block_arena() const THROWS;
-
 private:
     // This is thread safe.
-    mutable std::atomic_size_t count_;
+    std::atomic_size_t count_{};
 
     // This is protected by constructor init and thread_local indexation.
-    mutable std::vector<block_arena> arenas_;
+    std::vector<block_arena> arenas_{};
 };
 
 } // namespace node
diff --git a/src/block_memory.cpp b/src/block_memory.cpp
index b1e7b203..d63f878a 100644
--- a/src/block_memory.cpp
+++ b/src/block_memory.cpp
@@ -28,30 +28,19 @@ namespace node {
 BC_PUSH_WARNING(NO_THROW_IN_NOEXCEPT)
 
 block_memory::block_memory(size_t multiple, size_t threads) NOEXCEPT
-  : count_{}, arenas_{}
 {
-    arenas_.reserve(threads);
-    for (auto index = zero; index < threads; ++index)
-        arenas_.emplace_back(multiple);
+    if (is_nonzero(multiple))
+    {
+        arenas_.reserve(threads);
+        for (auto index = zero; index < threads; ++index)
+            arenas_.emplace_back(multiple);
+    }
 }
 
 arena* block_memory::get_arena() NOEXCEPT
 {
-    return get_block_arena();
-}
-
-// protected
-block_arena* block_memory::get_block_arena() const THROWS
-{
-    static thread_local auto index = count_.fetch_add(one,
-        std::memory_order_relaxed);
-
-    // More threads are requesting an arena than specified at construct.
-    ////BC_ASSERT(index < arenas_.size());
-    if (index >= arenas_.size())
-        throw allocation_exception{};
-
-    return &arenas_.at(index);
+    thread_local auto thread = count_.fetch_add(one, std::memory_order_relaxed);
+    return thread < arenas_.size() ? &arenas_.at(thread) : default_arena::get();
 }
 
 BC_POP_WARNING()
diff --git a/src/parser.cpp b/src/parser.cpp
index ee0874fb..c4a6397b 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -900,7 +900,7 @@ options_metadata parser::load_settings() THROWS
     (
         "node.allocation_multiple",
         value<uint16_t>(&configured.node.allocation_multiple),
-        "Per thread block deserialization buffer multiple of wire size, defaults to 20."
+        "Block deserialization buffer multiple of wire size, defaults to 20 (0 disables)."
     )
     (
         "node.maximum_height",