Fix win socket, acceptor cancelation

Author: vinniefalco

include/boost/corosio/acceptor.hpp

@@ -27,6 +27,7 @@
 #include <concepts>
 #include <coroutine>
 #include <cstddef>
+#include <memory>
 #include <stop_token>
 #include <type_traits>
 
@@ -275,7 +276,6 @@ class BOOST_COROSIO_DECL acceptor : public io_object
     };
 
 private:
-
     inline acceptor_impl& get() const noexcept
     {
         return *static_cast<acceptor_impl*>(impl_);

include/boost/corosio/socket.hpp

@@ -27,6 +27,7 @@
 #include <concepts>
 #include <coroutine>
 #include <cstddef>
+#include <memory>
 #include <stop_token>
 #include <type_traits>
 

src/corosio/src/acceptor.cpp

@@ -56,13 +56,18 @@ listen(endpoint ep, int backlog)
         close();
 
     auto& svc = ctx_->use_service<acceptor_service>();
-    auto& impl = svc.create_acceptor_impl();
-    impl_ = &impl;
+    auto& wrapper = svc.create_acceptor_impl();
+    impl_ = &wrapper;
 
-    system::error_code ec = svc.open_acceptor(impl, ep, backlog);
+#if defined(BOOST_COROSIO_BACKEND_IOCP)
+    system::error_code ec = svc.open_acceptor(
+        *wrapper.get_internal(), ep, backlog);
+#elif defined(BOOST_COROSIO_BACKEND_EPOLL)
+    system::error_code ec = svc.open_acceptor(wrapper, ep, backlog);
+#endif
     if (ec)
     {
-        impl.release();
+        wrapper.release();
         impl_ = nullptr;
         detail::throw_system_error(ec, "acceptor::listen");
     }
@@ -75,7 +80,8 @@ close()
     if (!impl_)
         return;
 
-    impl_->release();
+    auto* wrapper = static_cast<acceptor_impl_type*>(impl_);
+    wrapper->release();
     impl_ = nullptr;
 }
 
@@ -84,7 +90,11 @@ acceptor::
 cancel()
 {
     assert(impl_ != nullptr);
+#if defined(BOOST_COROSIO_BACKEND_IOCP)
+    static_cast<acceptor_impl_type*>(impl_)->get_internal()->cancel();
+#elif defined(BOOST_COROSIO_BACKEND_EPOLL)
     static_cast<acceptor_impl_type*>(impl_)->cancel();
+#endif
 }
 
 } // namespace corosio

src/corosio/src/detail/epoll/op.hpp

@@ -170,12 +170,20 @@ struct epoll_read_op : epoll_op
     iovec iovecs[max_buffers];
     int iovec_count = 0;
 
-    bool is_read_operation() const noexcept override { return true; }
+    // True when 0 bytes is due to empty buffer, not EOF
+    bool empty_buffer_read = false;
+
+    // EOF only applies when we actually tried to read something
+    bool is_read_operation() const noexcept override
+    {
+        return !empty_buffer_read;
+    }
 
     void reset() noexcept
     {
         epoll_op::reset();
         iovec_count = 0;
+        empty_buffer_read = false;
     }
 
     void perform_io() noexcept override

src/corosio/src/detail/epoll/sockets.hpp

@@ -292,6 +292,16 @@ read_some(
 
     capy::mutable_buffer bufs[epoll_read_op::max_buffers];
     op.iovec_count = static_cast<int>(param.copy_to(bufs, epoll_read_op::max_buffers));
+
+    // Handle empty buffer: complete immediately with 0 bytes
+    if (op.iovec_count == 0)
+    {
+        op.empty_buffer_read = true;
+        op.complete(0, 0);
+        svc_.post(&op);
+        return;
+    }
+
     for (int i = 0; i < op.iovec_count; ++i)
     {
         op.iovecs[i].iov_base = bufs[i].data();
@@ -346,6 +356,15 @@ write_some(
 
     capy::mutable_buffer bufs[epoll_write_op::max_buffers];
     op.iovec_count = static_cast<int>(param.copy_to(bufs, epoll_write_op::max_buffers));
+
+    // Handle empty buffer: complete immediately with 0 bytes
+    if (op.iovec_count == 0)
+    {
+        op.complete(0, 0);
+        svc_.post(&op);
+        return;
+    }
+
     for (int i = 0; i < op.iovec_count; ++i)
     {
         op.iovecs[i].iov_base = bufs[i].data();

src/corosio/src/detail/iocp/overlapped_op.hpp

@@ -89,15 +89,25 @@ struct overlapped_op
         if (ec_out)
         {
             if (cancelled.load(std::memory_order_acquire))
-                *ec_out = make_error_code(system::errc::operation_canceled);
+            {
+                // Explicit cancellation via cancel() or stop_token
+                *ec_out = capy::error::canceled;
+            }
+            else if (error == ERROR_OPERATION_ABORTED)
+            {
+                // CancelIoEx or socket close caused abort
+                *ec_out = capy::error::canceled;
+            }
             else if (error != 0)
+            {
                 *ec_out = system::error_code(
                     static_cast<int>(error), system::system_category());
+            }
             else if (is_read_operation() && bytes_transferred == 0 && !empty_buffer)
             {
                 // EOF: 0 bytes transferred with no error indicates end of stream
                 // (but not if we intentionally read with an empty buffer)
-                *ec_out = make_error_code(capy::error::eof);
+                *ec_out = capy::error::eof;
             }
         }