Initial Commit

include/asio/detail/descriptor_read_op.hpp

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+//
+// detail/descriptor_read_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP
+#define ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/descriptor_ops.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_work.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/dispatch.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence>
+class descriptor_read_op_base : public reactor_op
+{
+public:
+  descriptor_read_op_base(const asio::error_code& success_ec,
+      int descriptor, const MutableBufferSequence& buffers,
+      func_type complete_func)
+    : reactor_op(success_ec,
+        &descriptor_read_op_base::do_perform, complete_func),
+      descriptor_(descriptor),
+      buffers_(buffers)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    ASIO_ASSUME(base != 0);
+    descriptor_read_op_base* o(static_cast<descriptor_read_op_base*>(base));
+
+    typedef buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs_type;
+
+    status result;
+    if (bufs_type::is_single_buffer)
+    {
+      result = descriptor_ops::non_blocking_read1(o->descriptor_,
+          bufs_type::first(o->buffers_).data(),
+          bufs_type::first(o->buffers_).size(),
+          o->ec_, o->bytes_transferred_) ? done : not_done;
+    }
+    else
+    {
+      bufs_type bufs(o->buffers_);
+      result = descriptor_ops::non_blocking_read(o->descriptor_,
+          bufs.buffers(), bufs.count(), o->ec_, o->bytes_transferred_)
+        ? done : not_done;
+    }
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_read",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  int descriptor_;
+  MutableBufferSequence buffers_;
+};
+
+template <typename MutableBufferSequence, typename Handler, typename IoExecutor>
+class descriptor_read_op
+  : public descriptor_read_op_base<MutableBufferSequence>
+{
+public:
+  typedef Handler handler_type;
+  typedef IoExecutor io_executor_type;
+
+  ASIO_DEFINE_HANDLER_PTR(descriptor_read_op);
+
+  descriptor_read_op(const asio::error_code& success_ec,
+      int descriptor, const MutableBufferSequence& buffers,
+      Handler& handler, const IoExecutor& io_ex)
+    : descriptor_read_op_base<MutableBufferSequence>(success_ec,
+        descriptor, buffers, &descriptor_read_op::do_complete),
+      handler_(static_cast<Handler&&>(handler)),
+      work_(handler_, io_ex)
+  {
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    ASIO_ASSUME(base != 0);
+    descriptor_read_op* o(static_cast<descriptor_read_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Take ownership of the operation's outstanding work.
+    handler_work<Handler, IoExecutor> w(
+        static_cast<handler_work<Handler, IoExecutor>&&>(
+          o->work_));
+
+    ASIO_ERROR_LOCATION(o->ec_);
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+  static void do_immediate(operation* base, bool, const void* io_ex)
+  {
+    // Take ownership of the handler object.
+    ASIO_ASSUME(base != 0);
+    descriptor_read_op* o(static_cast<descriptor_read_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Take ownership of the operation's outstanding work.
+    immediate_handler_work<Handler, IoExecutor> w(
+        static_cast<handler_work<Handler, IoExecutor>&&>(
+          o->work_));
+
+    ASIO_ERROR_LOCATION(o->ec_);
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+    w.complete(handler, handler.handler_, io_ex);
+    ASIO_HANDLER_INVOCATION_END;
+  }
+
+private:
+  Handler handler_;
+  handler_work<Handler, IoExecutor> work_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP