Add test for releasing connections back to the server

src/connection_registry.cpp

@@ -1,5 +1,6 @@
 #include "connection_registry.hpp"
 #include "connection.hpp"
+#include <atomic>
 #include <cstring>
 #include <stdexcept>
 #include <unistd.h>
@@ -19,7 +20,7 @@ ConnectionRegistry::ConnectionRegistry() : connections_(nullptr), max_fds_(0) {
 
   // Allocate virtual address space using mmap
   // MAP_ANONYMOUS provides zero-initialized pages on-demand (lazy allocation)
-  connections_ = static_cast<Connection **>(
+  connections_ = static_cast<std::atomic<Connection *> *>(
       mmap(nullptr, aligned_size, PROT_READ | PROT_WRITE,
            MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
 
@@ -34,7 +35,7 @@ ConnectionRegistry::ConnectionRegistry() : connections_(nullptr), max_fds_(0) {
 ConnectionRegistry::~ConnectionRegistry() {
   if (connections_ != nullptr) {
     for (size_t fd = 0; fd < max_fds_; ++fd) {
-      delete connections_[fd];
+      delete connections_[fd].load(std::memory_order_relaxed);
     }
     if (munmap(connections_, aligned_size_) == -1) {
       perror("munmap");
@@ -47,16 +48,13 @@ void ConnectionRegistry::store(int fd, std::unique_ptr<Connection> connection) {
     abort();
   }
   // Release ownership from unique_ptr and store raw pointer
-  connections_[fd] = connection.release();
+  connections_[fd].store(connection.release(), std::memory_order_release);
 }
 
 std::unique_ptr<Connection> ConnectionRegistry::remove(int fd) {
   if (fd < 0 || static_cast<size_t>(fd) >= max_fds_) {
     abort();
   }
-
-  Connection *conn = connections_[fd];
-  connections_[fd] = nullptr;
-  // Transfer ownership back to unique_ptr
-  return std::unique_ptr<Connection>(conn);
+  return std::unique_ptr<Connection>(
+      connections_[fd].exchange(nullptr, std::memory_order_acquire));
 }