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-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/c_callback_wrapper.cpp230
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/callback_wrapper.cpp152
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_1.cpp155
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_2.cpp219
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_3.cpp228
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_4.cpp242
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_5.cpp280
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_6.cpp340
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_7.cpp261
-rw-r--r--3rdparty/asio/src/examples/cpp14/operations/composed_8.cpp254
10 files changed, 2361 insertions, 0 deletions
diff --git a/3rdparty/asio/src/examples/cpp14/operations/c_callback_wrapper.cpp b/3rdparty/asio/src/examples/cpp14/operations/c_callback_wrapper.cpp
new file mode 100644
index 00000000000..33b1c26e8ae
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/c_callback_wrapper.cpp
@@ -0,0 +1,230 @@
+//
+// c_callback_wrapper.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio.hpp>
+#include <iostream>
+#include <memory>
+#include <new>
+
+//------------------------------------------------------------------------------
+
+// This is a mock implementation of a C-based API that uses the function pointer
+// plus void* context idiom for exposing a callback.
+
+void read_input(const char* prompt, void (*cb)(void*, const char*), void* arg)
+{
+ std::thread(
+ [prompt = std::string(prompt), cb, arg]
+ {
+ std::cout << prompt << ": ";
+ std::cout.flush();
+ std::string line;
+ std::getline(std::cin, line);
+ cb(arg, line.c_str());
+ }).detach();
+}
+
+//------------------------------------------------------------------------------
+
+// This is an asynchronous operation that wraps the C-based API.
+
+// To map our completion handler into a function pointer / void* callback, we
+// need to allocate some state that will live for the duration of the
+// operation. A pointer to this state will be passed to the C-based API.
+template <typename Handler>
+class read_input_state
+{
+public:
+ read_input_state(Handler&& handler)
+ : handler_(std::move(handler)),
+ work_(asio::make_work_guard(handler_))
+ {
+ }
+
+ // Create the state using the handler's associated allocator.
+ static read_input_state* create(Handler&& handler)
+ {
+ // A unique_ptr deleter that is used to destroy uninitialised objects.
+ struct deleter
+ {
+ // Get the handler's associated allocator type. If the handler does not
+ // specify an associated allocator, we will use a recycling allocator as
+ // the default. As the associated allocator is a proto-allocator, we must
+ // rebind it to the correct type before we can use it to allocate objects.
+ typename std::allocator_traits<
+ asio::associated_allocator_t<Handler,
+ asio::recycling_allocator<void>>>::template
+ rebind_alloc<read_input_state> alloc;
+
+ void operator()(read_input_state* ptr)
+ {
+ std::allocator_traits<decltype(alloc)>::deallocate(alloc, ptr, 1);
+ }
+ } d{asio::get_associated_allocator(handler,
+ asio::recycling_allocator<void>())};
+
+ // Allocate memory for the state.
+ std::unique_ptr<read_input_state, deleter> uninit_ptr(
+ std::allocator_traits<decltype(d.alloc)>::allocate(d.alloc, 1), d);
+
+ // Construct the state into the newly allocated memory. This might throw.
+ read_input_state* ptr =
+ new (uninit_ptr.get()) read_input_state(std::move(handler));
+
+ // Release ownership of the memory and return the newly allocated state.
+ uninit_ptr.release();
+ return ptr;
+ }
+
+ static void callback(void* arg, const char* result)
+ {
+ read_input_state* self = static_cast<read_input_state*>(arg);
+
+ // A unique_ptr deleter that is used to destroy initialised objects.
+ struct deleter
+ {
+ // Get the handler's associated allocator type. If the handler does not
+ // specify an associated allocator, we will use a recycling allocator as
+ // the default. As the associated allocator is a proto-allocator, we must
+ // rebind it to the correct type before we can use it to allocate objects.
+ typename std::allocator_traits<
+ asio::associated_allocator_t<Handler,
+ asio::recycling_allocator<void>>>::template
+ rebind_alloc<read_input_state> alloc;
+
+ void operator()(read_input_state* ptr)
+ {
+ std::allocator_traits<decltype(alloc)>::destroy(alloc, ptr);
+ std::allocator_traits<decltype(alloc)>::deallocate(alloc, ptr, 1);
+ }
+ } d{asio::get_associated_allocator(self->handler_,
+ asio::recycling_allocator<void>())};
+
+ // To conform to the rules regarding asynchronous operations and memory
+ // allocation, we must make a copy of the state and deallocate the memory
+ // before dispatching the completion handler.
+ std::unique_ptr<read_input_state, deleter> state_ptr(self, d);
+ read_input_state state(std::move(*self));
+ state_ptr.reset();
+
+ // Dispatch the completion handler through the handler's associated
+ // executor, using the handler's associated allocator.
+ asio::dispatch(state.work_.get_executor(),
+ asio::bind_allocator(d.alloc,
+ [
+ handler = std::move(state.handler_),
+ result = std::string(result)
+ ]() mutable
+ {
+ std::move(handler)(result);
+ }));
+ }
+
+private:
+ Handler handler_;
+
+ // According to the rules for asynchronous operations, we need to track
+ // outstanding work against the handler's associated executor until the
+ // asynchronous operation is complete.
+ asio::executor_work_guard<
+ asio::associated_executor_t<Handler>> work_;
+};
+
+// The initiating function for the asynchronous operation.
+template <typename CompletionToken>
+auto async_read_input(const std::string& prompt, CompletionToken&& token)
+{
+ // Define a function object that contains the code to launch the asynchronous
+ // operation. This is passed the concrete completion handler, followed by any
+ // additional arguments that were passed through the call to async_initiate.
+ auto init = [](auto handler, const std::string& prompt)
+ {
+ // The body of the initiation function object creates the long-lived state
+ // and passes it to the C-based API, along with the function pointer.
+ using state_type = read_input_state<decltype(handler)>;
+ read_input(prompt.c_str(), &state_type::callback,
+ state_type::create(std::move(handler)));
+ };
+
+ // The async_initiate function is used to transform the supplied completion
+ // token to the completion handler. When calling this function we explicitly
+ // specify the completion signature of the operation. We must also return the
+ // result of the call since the completion token may produce a return value,
+ // such as a future.
+ return asio::async_initiate<CompletionToken, void(std::string)>(
+ init, // First, pass the function object that launches the operation,
+ token, // then the completion token that will be transformed to a handler,
+ prompt); // and, finally, any additional arguments to the function object.
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ // Test our asynchronous operation using a lambda as a callback. We will use
+ // an io_context to obtain an associated executor.
+ async_read_input("Enter your name",
+ asio::bind_executor(io_context,
+ [](const std::string& result)
+ {
+ std::cout << "Hello " << result << "\n";
+ }));
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_read_input("Enter your name", asio::deferred);
+
+ // Launch our asynchronous operation using a lambda as a callback. We will use
+ // an io_context to obtain an associated executor.
+ std::move(op)(
+ asio::bind_executor(io_context,
+ [](const std::string& result)
+ {
+ std::cout << "Hello " << result << "\n";
+ }));
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<std::string> f =
+ async_read_input("Enter your name", asio::use_future);
+
+ std::string result = f.get();
+ std::cout << "Hello " << result << "\n";
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/callback_wrapper.cpp b/3rdparty/asio/src/examples/cpp14/operations/callback_wrapper.cpp
new file mode 100644
index 00000000000..3d5774c7421
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/callback_wrapper.cpp
@@ -0,0 +1,152 @@
+//
+// callback_wrapper.cpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio.hpp>
+#include <iostream>
+
+//------------------------------------------------------------------------------
+
+// This is a mock implementation of an API that uses a move-only function object
+// for exposing a callback. The callback has the signature void(std::string).
+
+template <typename Callback>
+void read_input(const std::string& prompt, Callback cb)
+{
+ std::thread(
+ [prompt, cb = std::move(cb)]() mutable
+ {
+ std::cout << prompt << ": ";
+ std::cout.flush();
+ std::string line;
+ std::getline(std::cin, line);
+ std::move(cb)(std::move(line));
+ }).detach();
+}
+
+//------------------------------------------------------------------------------
+
+// This is an asynchronous operation that wraps the callback-based API.
+
+// The initiating function for the asynchronous operation.
+template <typename CompletionToken>
+auto async_read_input(const std::string& prompt, CompletionToken&& token)
+{
+ // Define a function object that contains the code to launch the asynchronous
+ // operation. This is passed the concrete completion handler, followed by any
+ // additional arguments that were passed through the call to async_initiate.
+ auto init = [](auto handler, const std::string& prompt)
+ {
+ // According to the rules for asynchronous operations, we need to track
+ // outstanding work against the handler's associated executor until the
+ // asynchronous operation is complete.
+ auto work = asio::make_work_guard(handler);
+
+ // Launch the operation with a callback that will receive the result and
+ // pass it through to the asynchronous operation's completion handler.
+ read_input(prompt,
+ [
+ handler = std::move(handler),
+ work = std::move(work)
+ ](std::string result) mutable
+ {
+ // Get the handler's associated allocator. If the handler does not
+ // specify an allocator, use the recycling allocator as the default.
+ auto alloc = asio::get_associated_allocator(
+ handler, asio::recycling_allocator<void>());
+
+ // Dispatch the completion handler through the handler's associated
+ // executor, using the handler's associated allocator.
+ asio::dispatch(work.get_executor(),
+ asio::bind_allocator(alloc,
+ [
+ handler = std::move(handler),
+ result = std::string(result)
+ ]() mutable
+ {
+ std::move(handler)(result);
+ }));
+ });
+ };
+
+ // The async_initiate function is used to transform the supplied completion
+ // token to the completion handler. When calling this function we explicitly
+ // specify the completion signature of the operation. We must also return the
+ // result of the call since the completion token may produce a return value,
+ // such as a future.
+ return asio::async_initiate<CompletionToken, void(std::string)>(
+ init, // First, pass the function object that launches the operation,
+ token, // then the completion token that will be transformed to a handler,
+ prompt); // and, finally, any additional arguments to the function object.
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ // Test our asynchronous operation using a lambda as a callback. We will use
+ // an io_context to specify an associated executor.
+ async_read_input("Enter your name",
+ asio::bind_executor(io_context,
+ [](const std::string& result)
+ {
+ std::cout << "Hello " << result << "\n";
+ }));
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_read_input("Enter your name", asio::deferred);
+
+ // Launch our asynchronous operation using a lambda as a callback. We will use
+ // an io_context to obtain an associated executor.
+ std::move(op)(
+ asio::bind_executor(io_context,
+ [](const std::string& result)
+ {
+ std::cout << "Hello " << result << "\n";
+ }));
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<std::string> f =
+ async_read_input("Enter your name", asio::use_future);
+
+ std::string result = f.get();
+ std::cout << "Hello " << result << "\n";
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_1.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_1.cpp
new file mode 100644
index 00000000000..80eaceddf71
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_1.cpp
@@ -0,0 +1,155 @@
+//
+// composed_1.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/deferred.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+//------------------------------------------------------------------------------
+
+// This is the simplest example of a composed asynchronous operation, where we
+// simply repackage an existing operation. The asynchronous operation
+// requirements are met by delegating responsibility to the underlying
+// operation.
+
+template <typename CompletionToken>
+auto async_write_message(tcp::socket& socket,
+ const char* message, CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is void.
+ // However, when the completion token is asio::yield_context (used for
+ // stackful coroutines) the return type would be std::size_t, and when the
+ // completion token is asio::use_future it would be std::future<std::size_t>.
+ // When the completion token is asio::deferred, the return type differs for
+ // each asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of our underlying asynchronous operation.
+{
+ // When delegating to the underlying operation we must take care to perfectly
+ // forward the completion token. This ensures that our operation works
+ // correctly with move-only function objects as callbacks, as well as other
+ // completion token types.
+ return asio::async_write(socket,
+ asio::buffer(message, std::strlen(message)),
+ std::forward<CompletionToken>(token));
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_message(socket, "Testing callback\r\n",
+ [](const std::error_code& error, std::size_t n)
+ {
+ if (!error)
+ {
+ std::cout << n << " bytes transferred\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_message(socket,
+ "Testing deferred\r\n", asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error, std::size_t n)
+ {
+ if (!error)
+ {
+ std::cout << n << " bytes transferred\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<std::size_t> f = async_write_message(
+ socket, "Testing future\r\n", asio::use_future);
+
+ io_context.run();
+
+ try
+ {
+ // Get the result of the operation.
+ std::size_t n = f.get();
+ std::cout << n << " bytes transferred\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Error: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_2.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_2.cpp
new file mode 100644
index 00000000000..18086bd0627
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_2.cpp
@@ -0,0 +1,219 @@
+//
+// composed_2.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/deferred.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+// NOTE: This example requires the new asio::async_initiate function. For
+// an example that works with the Networking TS style of completion tokens,
+// please see an older version of asio.
+
+//------------------------------------------------------------------------------
+
+// This next simplest example of a composed asynchronous operation involves
+// repackaging multiple operations but choosing to invoke just one of them. All
+// of these underlying operations have the same completion signature. The
+// asynchronous operation requirements are met by delegating responsibility to
+// the underlying operations.
+
+template <typename CompletionToken>
+auto async_write_message(tcp::socket& socket,
+ const char* message, bool allow_partial_write,
+ CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is void.
+ // However, when the completion token is asio::yield_context (used for
+ // stackful coroutines) the return type would be std::size_t, and when the
+ // completion token is asio::use_future it would be std::future<std::size_t>.
+ // When the completion token is asio::deferred, the return type differs for
+ // each asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of asio::async_initiate.
+{
+ // In addition to determining the mechanism by which an asynchronous
+ // operation delivers its result, a completion token also determines the time
+ // when the operation commences. For example, when the completion token is a
+ // simple callback the operation commences before the initiating function
+ // returns. However, if the completion token's delivery mechanism uses a
+ // future, we might instead want to defer initiation of the operation until
+ // the returned future object is waited upon.
+ //
+ // To enable this, when implementing an asynchronous operation we must
+ // package the initiation step as a function object. The initiation function
+ // object's call operator is passed the concrete completion handler produced
+ // by the completion token. This completion handler matches the asynchronous
+ // operation's completion handler signature, which in this example is:
+ //
+ // void(std::error_code error, std::size_t)
+ //
+ // The initiation function object also receives any additional arguments
+ // required to start the operation. (Note: We could have instead passed these
+ // arguments in the lambda capture set. However, we should prefer to
+ // propagate them as function call arguments as this allows the completion
+ // token to optimise how they are passed. For example, a lazy future which
+ // defers initiation would need to make a decay-copy of the arguments, but
+ // when using a simple callback the arguments can be trivially forwarded
+ // straight through.)
+ auto initiation = [](auto&& completion_handler, tcp::socket& socket,
+ const char* message, bool allow_partial_write)
+ {
+ if (allow_partial_write)
+ {
+ // When delegating to an underlying operation we must take care to
+ // perfectly forward the completion handler. This ensures that our
+ // operation works correctly with move-only function objects as
+ // callbacks.
+ return socket.async_write_some(
+ asio::buffer(message, std::strlen(message)),
+ std::forward<decltype(completion_handler)>(completion_handler));
+ }
+ else
+ {
+ // As above, we must perfectly forward the completion handler when calling
+ // the alternate underlying operation.
+ return asio::async_write(socket,
+ asio::buffer(message, std::strlen(message)),
+ std::forward<decltype(completion_handler)>(completion_handler));
+ }
+ };
+
+ // The asio::async_initiate function takes:
+ //
+ // - our initiation function object,
+ // - the completion token,
+ // - the completion handler signature, and
+ // - any additional arguments we need to initiate the operation.
+ //
+ // It then asks the completion token to create a completion handler (i.e. a
+ // callback) with the specified signature, and invoke the initiation function
+ // object with this completion handler as well as the additional arguments.
+ // The return value of async_initiate is the result of our operation's
+ // initiating function.
+ //
+ // Note that we wrap non-const reference arguments in std::reference_wrapper
+ // to prevent incorrect decay-copies of these objects.
+ return asio::async_initiate<
+ CompletionToken, void(std::error_code, std::size_t)>(
+ initiation, token, std::ref(socket), message, allow_partial_write);
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_message(socket, "Testing callback\r\n", false,
+ [](const std::error_code& error, std::size_t n)
+ {
+ if (!error)
+ {
+ std::cout << n << " bytes transferred\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_message(socket,
+ "Testing deferred\r\n", false, asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error, std::size_t n)
+ {
+ if (!error)
+ {
+ std::cout << n << " bytes transferred\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<std::size_t> f = async_write_message(
+ socket, "Testing future\r\n", false, asio::use_future);
+
+ io_context.run();
+
+ try
+ {
+ // Get the result of the operation.
+ std::size_t n = f.get();
+ std::cout << n << " bytes transferred\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Error: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_3.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_3.cpp
new file mode 100644
index 00000000000..7b347944768
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_3.cpp
@@ -0,0 +1,228 @@
+//
+// composed_3.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/bind_executor.hpp>
+#include <asio/deferred.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <cstring>
+#include <functional>
+#include <iostream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+// NOTE: This example requires the new asio::async_initiate function. For
+// an example that works with the Networking TS style of completion tokens,
+// please see an older version of asio.
+
+//------------------------------------------------------------------------------
+
+// In this composed operation we repackage an existing operation, but with a
+// different completion handler signature. The asynchronous operation
+// requirements are met by delegating responsibility to the underlying
+// operation.
+
+template <typename CompletionToken>
+auto async_write_message(tcp::socket& socket,
+ const char* message, CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is always
+ // void. In this example, when the completion token is asio::yield_context
+ // (used for stackful coroutines) the return type would also be void, as
+ // there is no non-error argument to the completion handler. When the
+ // completion token is asio::use_future it would be std::future<void>. When
+ // the completion token is asio::deferred, the return type differs for each
+ // asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of asio::async_initiate.
+{
+ // In addition to determining the mechanism by which an asynchronous
+ // operation delivers its result, a completion token also determines the time
+ // when the operation commences. For example, when the completion token is a
+ // simple callback the operation commences before the initiating function
+ // returns. However, if the completion token's delivery mechanism uses a
+ // future, we might instead want to defer initiation of the operation until
+ // the returned future object is waited upon.
+ //
+ // To enable this, when implementing an asynchronous operation we must
+ // package the initiation step as a function object. The initiation function
+ // object's call operator is passed the concrete completion handler produced
+ // by the completion token. This completion handler matches the asynchronous
+ // operation's completion handler signature, which in this example is:
+ //
+ // void(std::error_code error)
+ //
+ // The initiation function object also receives any additional arguments
+ // required to start the operation. (Note: We could have instead passed these
+ // arguments in the lambda capture set. However, we should prefer to
+ // propagate them as function call arguments as this allows the completion
+ // token to optimise how they are passed. For example, a lazy future which
+ // defers initiation would need to make a decay-copy of the arguments, but
+ // when using a simple callback the arguments can be trivially forwarded
+ // straight through.)
+ auto initiation = [](auto&& completion_handler,
+ tcp::socket& socket, const char* message)
+ {
+ // The async_write operation has a completion handler signature of:
+ //
+ // void(std::error_code error, std::size n)
+ //
+ // This differs from our operation's signature in that it is also passed
+ // the number of bytes transferred as an argument of type std::size_t. We
+ // will adapt our completion handler to async_write's completion handler
+ // signature by using std::bind, which drops the additional argument.
+ //
+ // However, it is essential to the correctness of our composed operation
+ // that we preserve the executor of the user-supplied completion handler.
+ // The std::bind function will not do this for us, so we must do this by
+ // first obtaining the completion handler's associated executor (defaulting
+ // to the I/O executor - in this case the executor of the socket - if the
+ // completion handler does not have its own) ...
+ auto executor = asio::get_associated_executor(
+ completion_handler, socket.get_executor());
+
+ // ... and then binding this executor to our adapted completion handler
+ // using the asio::bind_executor function.
+ asio::async_write(socket,
+ asio::buffer(message, std::strlen(message)),
+ asio::bind_executor(executor,
+ std::bind(std::forward<decltype(completion_handler)>(
+ completion_handler), std::placeholders::_1)));
+ };
+
+ // The asio::async_initiate function takes:
+ //
+ // - our initiation function object,
+ // - the completion token,
+ // - the completion handler signature, and
+ // - any additional arguments we need to initiate the operation.
+ //
+ // It then asks the completion token to create a completion handler (i.e. a
+ // callback) with the specified signature, and invoke the initiation function
+ // object with this completion handler as well as the additional arguments.
+ // The return value of async_initiate is the result of our operation's
+ // initiating function.
+ //
+ // Note that we wrap non-const reference arguments in std::reference_wrapper
+ // to prevent incorrect decay-copies of these objects.
+ return asio::async_initiate<
+ CompletionToken, void(std::error_code)>(
+ initiation, token, std::ref(socket), message);
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_message(socket, "Testing callback\r\n",
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Message sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_message(socket,
+ "Testing deferred\r\n", asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Message sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<void> f = async_write_message(
+ socket, "Testing future\r\n", asio::use_future);
+
+ io_context.run();
+
+ // Get the result of the operation.
+ try
+ {
+ // Get the result of the operation.
+ f.get();
+ std::cout << "Message sent\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Error: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_4.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_4.cpp
new file mode 100644
index 00000000000..808a179e2d3
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_4.cpp
@@ -0,0 +1,242 @@
+//
+// composed_4.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/bind_executor.hpp>
+#include <asio/deferred.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <cstring>
+#include <functional>
+#include <iostream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+// NOTE: This example requires the new asio::async_initiate function. For
+// an example that works with the Networking TS style of completion tokens,
+// please see an older version of asio.
+
+//------------------------------------------------------------------------------
+
+// In this composed operation we repackage an existing operation, but with a
+// different completion handler signature. We will also intercept an empty
+// message as an invalid argument, and propagate the corresponding error to the
+// user. The asynchronous operation requirements are met by delegating
+// responsibility to the underlying operation.
+
+template <typename CompletionToken>
+auto async_write_message(tcp::socket& socket,
+ const char* message, CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is always
+ // void. In this example, when the completion token is asio::yield_context
+ // (used for stackful coroutines) the return type would also be void, as
+ // there is no non-error argument to the completion handler. When the
+ // completion token is asio::use_future it would be std::future<void>. When
+ // the completion token is asio::deferred, the return type differs for each
+ // asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of asio::async_initiate.
+{
+ // In addition to determining the mechanism by which an asynchronous
+ // operation delivers its result, a completion token also determines the time
+ // when the operation commences. For example, when the completion token is a
+ // simple callback the operation commences before the initiating function
+ // returns. However, if the completion token's delivery mechanism uses a
+ // future, we might instead want to defer initiation of the operation until
+ // the returned future object is waited upon.
+ //
+ // To enable this, when implementing an asynchronous operation we must
+ // package the initiation step as a function object. The initiation function
+ // object's call operator is passed the concrete completion handler produced
+ // by the completion token. This completion handler matches the asynchronous
+ // operation's completion handler signature, which in this example is:
+ //
+ // void(std::error_code error)
+ //
+ // The initiation function object also receives any additional arguments
+ // required to start the operation. (Note: We could have instead passed these
+ // arguments in the lambda capture set. However, we should prefer to
+ // propagate them as function call arguments as this allows the completion
+ // token to optimise how they are passed. For example, a lazy future which
+ // defers initiation would need to make a decay-copy of the arguments, but
+ // when using a simple callback the arguments can be trivially forwarded
+ // straight through.)
+ auto initiation = [](auto&& completion_handler,
+ tcp::socket& socket, const char* message)
+ {
+ // The post operation has a completion handler signature of:
+ //
+ // void()
+ //
+ // and the async_write operation has a completion handler signature of:
+ //
+ // void(std::error_code error, std::size n)
+ //
+ // Both of these operations' completion handler signatures differ from our
+ // operation's completion handler signature. We will adapt our completion
+ // handler to these signatures by using std::bind, which drops the
+ // additional arguments.
+ //
+ // However, it is essential to the correctness of our composed operation
+ // that we preserve the executor of the user-supplied completion handler.
+ // The std::bind function will not do this for us, so we must do this by
+ // first obtaining the completion handler's associated executor (defaulting
+ // to the I/O executor - in this case the executor of the socket - if the
+ // completion handler does not have its own) ...
+ auto executor = asio::get_associated_executor(
+ completion_handler, socket.get_executor());
+
+ // ... and then binding this executor to our adapted completion handler
+ // using the asio::bind_executor function.
+ std::size_t length = std::strlen(message);
+ if (length == 0)
+ {
+ asio::post(
+ asio::bind_executor(executor,
+ std::bind(std::forward<decltype(completion_handler)>(
+ completion_handler), asio::error::invalid_argument)));
+ }
+ else
+ {
+ asio::async_write(socket,
+ asio::buffer(message, length),
+ asio::bind_executor(executor,
+ std::bind(std::forward<decltype(completion_handler)>(
+ completion_handler), std::placeholders::_1)));
+ }
+ };
+
+ // The asio::async_initiate function takes:
+ //
+ // - our initiation function object,
+ // - the completion token,
+ // - the completion handler signature, and
+ // - any additional arguments we need to initiate the operation.
+ //
+ // It then asks the completion token to create a completion handler (i.e. a
+ // callback) with the specified signature, and invoke the initiation function
+ // object with this completion handler as well as the additional arguments.
+ // The return value of async_initiate is the result of our operation's
+ // initiating function.
+ //
+ // Note that we wrap non-const reference arguments in std::reference_wrapper
+ // to prevent incorrect decay-copies of these objects.
+ return asio::async_initiate<
+ CompletionToken, void(std::error_code)>(
+ initiation, token, std::ref(socket), message);
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_message(socket, "",
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Message sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_message(socket, "", asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Message sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<void> f = async_write_message(
+ socket, "", asio::use_future);
+
+ io_context.run();
+
+ try
+ {
+ // Get the result of the operation.
+ f.get();
+ std::cout << "Message sent\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Exception: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_5.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_5.cpp
new file mode 100644
index 00000000000..c28cc8af129
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_5.cpp
@@ -0,0 +1,280 @@
+//
+// composed_5.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/deferred.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+// NOTE: This example requires the new asio::async_initiate function. For
+// an example that works with the Networking TS style of completion tokens,
+// please see an older version of asio.
+
+//------------------------------------------------------------------------------
+
+// This composed operation automatically serialises a message, using its I/O
+// streams insertion operator, before sending it on the socket. To do this, it
+// must allocate a buffer for the encoded message and ensure this buffer's
+// validity until the underlying async_write operation completes.
+
+template <typename T, typename CompletionToken>
+auto async_write_message(tcp::socket& socket,
+ const T& message, CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is always
+ // void. In this example, when the completion token is asio::yield_context
+ // (used for stackful coroutines) the return type would also be void, as
+ // there is no non-error argument to the completion handler. When the
+ // completion token is asio::use_future it would be std::future<void>. When
+ // the completion token is asio::deferred, the return type differs for each
+ // asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of asio::async_initiate.
+{
+ // In addition to determining the mechanism by which an asynchronous
+ // operation delivers its result, a completion token also determines the time
+ // when the operation commences. For example, when the completion token is a
+ // simple callback the operation commences before the initiating function
+ // returns. However, if the completion token's delivery mechanism uses a
+ // future, we might instead want to defer initiation of the operation until
+ // the returned future object is waited upon.
+ //
+ // To enable this, when implementing an asynchronous operation we must
+ // package the initiation step as a function object. The initiation function
+ // object's call operator is passed the concrete completion handler produced
+ // by the completion token. This completion handler matches the asynchronous
+ // operation's completion handler signature, which in this example is:
+ //
+ // void(std::error_code error)
+ //
+ // The initiation function object also receives any additional arguments
+ // required to start the operation. (Note: We could have instead passed these
+ // arguments in the lambda capture set. However, we should prefer to
+ // propagate them as function call arguments as this allows the completion
+ // token to optimise how they are passed. For example, a lazy future which
+ // defers initiation would need to make a decay-copy of the arguments, but
+ // when using a simple callback the arguments can be trivially forwarded
+ // straight through.)
+ auto initiation = [](auto&& completion_handler,
+ tcp::socket& socket, std::unique_ptr<std::string> encoded_message)
+ {
+ // In this example, the composed operation's intermediate completion
+ // handler is implemented as a hand-crafted function object, rather than
+ // using a lambda or std::bind.
+ struct intermediate_completion_handler
+ {
+ // The intermediate completion handler holds a reference to the socket so
+ // that it can obtain the I/O executor (see get_executor below).
+ tcp::socket& socket_;
+
+ // The allocated buffer for the encoded message. The std::unique_ptr
+ // smart pointer is move-only, and as a consequence our intermediate
+ // completion handler is also move-only.
+ std::unique_ptr<std::string> encoded_message_;
+
+ // The user-supplied completion handler.
+ typename std::decay<decltype(completion_handler)>::type handler_;
+
+ // The function call operator matches the completion signature of the
+ // async_write operation.
+ void operator()(const std::error_code& error, std::size_t /*n*/)
+ {
+ // Deallocate the encoded message before calling the user-supplied
+ // completion handler.
+ encoded_message_.reset();
+
+ // Call the user-supplied handler with the result of the operation.
+ // The arguments must match the completion signature of our composed
+ // operation.
+ handler_(error);
+ }
+
+ // It is essential to the correctness of our composed operation that we
+ // preserve the executor of the user-supplied completion handler. With a
+ // hand-crafted function object we can do this by defining a nested type
+ // executor_type and member function get_executor. These obtain the
+ // completion handler's associated executor, and default to the I/O
+ // executor - in this case the executor of the socket - if the completion
+ // handler does not have its own.
+ using executor_type = asio::associated_executor_t<
+ typename std::decay<decltype(completion_handler)>::type,
+ tcp::socket::executor_type>;
+
+ executor_type get_executor() const noexcept
+ {
+ return asio::get_associated_executor(
+ handler_, socket_.get_executor());
+ }
+
+ // Although not necessary for correctness, we may also preserve the
+ // allocator of the user-supplied completion handler. This is achieved by
+ // defining a nested type allocator_type and member function
+ // get_allocator. These obtain the completion handler's associated
+ // allocator, and default to std::allocator<void> if the completion
+ // handler does not have its own.
+ using allocator_type = asio::associated_allocator_t<
+ typename std::decay<decltype(completion_handler)>::type,
+ std::allocator<void>>;
+
+ allocator_type get_allocator() const noexcept
+ {
+ return asio::get_associated_allocator(
+ handler_, std::allocator<void>{});
+ }
+ };
+
+ // Initiate the underlying async_write operation using our intermediate
+ // completion handler.
+ auto encoded_message_buffer = asio::buffer(*encoded_message);
+ asio::async_write(socket, encoded_message_buffer,
+ intermediate_completion_handler{socket, std::move(encoded_message),
+ std::forward<decltype(completion_handler)>(completion_handler)});
+ };
+
+ // Encode the message and copy it into an allocated buffer. The buffer will
+ // be maintained for the lifetime of the asynchronous operation.
+ std::ostringstream os;
+ os << message;
+ std::unique_ptr<std::string> encoded_message(new std::string(os.str()));
+
+ // The asio::async_initiate function takes:
+ //
+ // - our initiation function object,
+ // - the completion token,
+ // - the completion handler signature, and
+ // - any additional arguments we need to initiate the operation.
+ //
+ // It then asks the completion token to create a completion handler (i.e. a
+ // callback) with the specified signature, and invoke the initiation function
+ // object with this completion handler as well as the additional arguments.
+ // The return value of async_initiate is the result of our operation's
+ // initiating function.
+ //
+ // Note that we wrap non-const reference arguments in std::reference_wrapper
+ // to prevent incorrect decay-copies of these objects.
+ return asio::async_initiate<
+ CompletionToken, void(std::error_code)>(
+ initiation, token, std::ref(socket),
+ std::move(encoded_message));
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_message(socket, 123456,
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Message sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_message(socket,
+ std::string("abcdef"), asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Message sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<void> f = async_write_message(
+ socket, 654.321, asio::use_future);
+
+ io_context.run();
+
+ try
+ {
+ // Get the result of the operation.
+ f.get();
+ std::cout << "Message sent\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Exception: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_6.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_6.cpp
new file mode 100644
index 00000000000..82c0cd72237
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_6.cpp
@@ -0,0 +1,340 @@
+//
+// composed_6.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/deferred.hpp>
+#include <asio/executor_work_guard.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/steady_timer.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+// NOTE: This example requires the new asio::async_initiate function. For
+// an example that works with the Networking TS style of completion tokens,
+// please see an older version of asio.
+
+//------------------------------------------------------------------------------
+
+// This composed operation shows composition of multiple underlying operations.
+// It automatically serialises a message, using its I/O streams insertion
+// operator, before sending it N times on the socket. To do this, it must
+// allocate a buffer for the encoded message and ensure this buffer's validity
+// until all underlying async_write operation complete. A one second delay is
+// inserted prior to each write operation, using a steady_timer.
+
+template <typename T, typename CompletionToken>
+auto async_write_messages(tcp::socket& socket,
+ const T& message, std::size_t repeat_count,
+ CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is always
+ // void. In this example, when the completion token is asio::yield_context
+ // (used for stackful coroutines) the return type would also be void, as
+ // there is no non-error argument to the completion handler. When the
+ // completion token is asio::use_future it would be std::future<void>. When
+ // the completion token is asio::deferred, the return type differs for each
+ // asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of asio::async_initiate.
+{
+ // In addition to determining the mechanism by which an asynchronous
+ // operation delivers its result, a completion token also determines the time
+ // when the operation commences. For example, when the completion token is a
+ // simple callback the operation commences before the initiating function
+ // returns. However, if the completion token's delivery mechanism uses a
+ // future, we might instead want to defer initiation of the operation until
+ // the returned future object is waited upon.
+ //
+ // To enable this, when implementing an asynchronous operation we must
+ // package the initiation step as a function object. The initiation function
+ // object's call operator is passed the concrete completion handler produced
+ // by the completion token. This completion handler matches the asynchronous
+ // operation's completion handler signature, which in this example is:
+ //
+ // void(std::error_code error)
+ //
+ // The initiation function object also receives any additional arguments
+ // required to start the operation. (Note: We could have instead passed these
+ // arguments in the lambda capture set. However, we should prefer to
+ // propagate them as function call arguments as this allows the completion
+ // token to optimise how they are passed. For example, a lazy future which
+ // defers initiation would need to make a decay-copy of the arguments, but
+ // when using a simple callback the arguments can be trivially forwarded
+ // straight through.)
+ auto initiation = [](auto&& completion_handler, tcp::socket& socket,
+ std::unique_ptr<std::string> encoded_message, std::size_t repeat_count,
+ std::unique_ptr<asio::steady_timer> delay_timer)
+ {
+ // In this example, the composed operation's intermediate completion
+ // handler is implemented as a hand-crafted function object.
+ struct intermediate_completion_handler
+ {
+ // The intermediate completion handler holds a reference to the socket as
+ // it is used for multiple async_write operations, as well as for
+ // obtaining the I/O executor (see get_executor below).
+ tcp::socket& socket_;
+
+ // The allocated buffer for the encoded message. The std::unique_ptr
+ // smart pointer is move-only, and as a consequence our intermediate
+ // completion handler is also move-only.
+ std::unique_ptr<std::string> encoded_message_;
+
+ // The repeat count remaining.
+ std::size_t repeat_count_;
+
+ // A steady timer used for introducing a delay.
+ std::unique_ptr<asio::steady_timer> delay_timer_;
+
+ // To manage the cycle between the multiple underlying asychronous
+ // operations, our intermediate completion handler is implemented as a
+ // state machine.
+ enum { starting, waiting, writing } state_;
+
+ // As our composed operation performs multiple underlying I/O operations,
+ // we should maintain a work object against the I/O executor. This tells
+ // the I/O executor that there is still more work to come in the future.
+ asio::executor_work_guard<tcp::socket::executor_type> io_work_;
+
+ // The user-supplied completion handler, called once only on completion
+ // of the entire composed operation.
+ typename std::decay<decltype(completion_handler)>::type handler_;
+
+ // By having a default value for the second argument, this function call
+ // operator matches the completion signature of both the async_write and
+ // steady_timer::async_wait operations.
+ void operator()(const std::error_code& error, std::size_t = 0)
+ {
+ if (!error)
+ {
+ switch (state_)
+ {
+ case starting:
+ case writing:
+ if (repeat_count_ > 0)
+ {
+ --repeat_count_;
+ state_ = waiting;
+ delay_timer_->expires_after(std::chrono::seconds(1));
+ delay_timer_->async_wait(std::move(*this));
+ return; // Composed operation not yet complete.
+ }
+ break; // Composed operation complete, continue below.
+ case waiting:
+ state_ = writing;
+ asio::async_write(socket_,
+ asio::buffer(*encoded_message_), std::move(*this));
+ return; // Composed operation not yet complete.
+ }
+ }
+
+ // This point is reached only on completion of the entire composed
+ // operation.
+
+ // We no longer have any future work coming for the I/O executor.
+ io_work_.reset();
+
+ // Deallocate the encoded message before calling the user-supplied
+ // completion handler.
+ encoded_message_.reset();
+
+ // Call the user-supplied handler with the result of the operation.
+ handler_(error);
+ }
+
+ // It is essential to the correctness of our composed operation that we
+ // preserve the executor of the user-supplied completion handler. With a
+ // hand-crafted function object we can do this by defining a nested type
+ // executor_type and member function get_executor. These obtain the
+ // completion handler's associated executor, and default to the I/O
+ // executor - in this case the executor of the socket - if the completion
+ // handler does not have its own.
+ using executor_type = asio::associated_executor_t<
+ typename std::decay<decltype(completion_handler)>::type,
+ tcp::socket::executor_type>;
+
+ executor_type get_executor() const noexcept
+ {
+ return asio::get_associated_executor(
+ handler_, socket_.get_executor());
+ }
+
+ // Although not necessary for correctness, we may also preserve the
+ // allocator of the user-supplied completion handler. This is achieved by
+ // defining a nested type allocator_type and member function
+ // get_allocator. These obtain the completion handler's associated
+ // allocator, and default to std::allocator<void> if the completion
+ // handler does not have its own.
+ using allocator_type = asio::associated_allocator_t<
+ typename std::decay<decltype(completion_handler)>::type,
+ std::allocator<void>>;
+
+ allocator_type get_allocator() const noexcept
+ {
+ return asio::get_associated_allocator(
+ handler_, std::allocator<void>{});
+ }
+ };
+
+ // Initiate the underlying async_write operation using our intermediate
+ // completion handler.
+ auto encoded_message_buffer = asio::buffer(*encoded_message);
+ asio::async_write(socket, encoded_message_buffer,
+ intermediate_completion_handler{
+ socket, std::move(encoded_message),
+ repeat_count, std::move(delay_timer),
+ intermediate_completion_handler::starting,
+ asio::make_work_guard(socket.get_executor()),
+ std::forward<decltype(completion_handler)>(completion_handler)});
+ };
+
+ // Encode the message and copy it into an allocated buffer. The buffer will
+ // be maintained for the lifetime of the composed asynchronous operation.
+ std::ostringstream os;
+ os << message;
+ std::unique_ptr<std::string> encoded_message(new std::string(os.str()));
+
+ // Create a steady_timer to be used for the delay between messages.
+ std::unique_ptr<asio::steady_timer> delay_timer(
+ new asio::steady_timer(socket.get_executor()));
+
+ // The asio::async_initiate function takes:
+ //
+ // - our initiation function object,
+ // - the completion token,
+ // - the completion handler signature, and
+ // - any additional arguments we need to initiate the operation.
+ //
+ // It then asks the completion token to create a completion handler (i.e. a
+ // callback) with the specified signature, and invoke the initiation function
+ // object with this completion handler as well as the additional arguments.
+ // The return value of async_initiate is the result of our operation's
+ // initiating function.
+ //
+ // Note that we wrap non-const reference arguments in std::reference_wrapper
+ // to prevent incorrect decay-copies of these objects.
+ return asio::async_initiate<
+ CompletionToken, void(std::error_code)>(
+ initiation, token, std::ref(socket),
+ std::move(encoded_message), repeat_count,
+ std::move(delay_timer));
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_messages(socket, "Testing callback\r\n", 5,
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Messages sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_messages(socket,
+ "Testing deferred\r\n", 5, asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Messages sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<void> f = async_write_messages(
+ socket, "Testing future\r\n", 5, asio::use_future);
+
+ io_context.run();
+
+ try
+ {
+ // Get the result of the operation.
+ f.get();
+ std::cout << "Messages sent\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Error: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_7.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_7.cpp
new file mode 100644
index 00000000000..841249bef5b
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_7.cpp
@@ -0,0 +1,261 @@
+//
+// composed_7.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/compose.hpp>
+#include <asio/deferred.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/steady_timer.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+// NOTE: This example requires the new asio::async_compose function. For
+// an example that works with the Networking TS style of completion tokens,
+// please see an older version of asio.
+
+//------------------------------------------------------------------------------
+
+// This composed operation shows composition of multiple underlying operations.
+// It automatically serialises a message, using its I/O streams insertion
+// operator, before sending it N times on the socket. To do this, it must
+// allocate a buffer for the encoded message and ensure this buffer's validity
+// until all underlying async_write operation complete. A one second delay is
+// inserted prior to each write operation, using a steady_timer.
+
+template <typename T, typename CompletionToken>
+auto async_write_messages(tcp::socket& socket,
+ const T& message, std::size_t repeat_count,
+ CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is always
+ // void. In this example, when the completion token is asio::yield_context
+ // (used for stackful coroutines) the return type would also be void, as
+ // there is no non-error argument to the completion handler. When the
+ // completion token is asio::use_future it would be std::future<void>. When
+ // the completion token is asio::deferred, the return type differs for each
+ // asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of asio::async_compose.
+{
+ // Encode the message and copy it into an allocated buffer. The buffer will
+ // be maintained for the lifetime of the composed asynchronous operation.
+ std::ostringstream os;
+ os << message;
+ std::unique_ptr<std::string> encoded_message(new std::string(os.str()));
+
+ // Create a steady_timer to be used for the delay between messages.
+ std::unique_ptr<asio::steady_timer> delay_timer(
+ new asio::steady_timer(socket.get_executor()));
+
+ // To manage the cycle between the multiple underlying asychronous
+ // operations, our implementation is a state machine.
+ enum { starting, waiting, writing };
+
+ // The asio::async_compose function takes:
+ //
+ // - our asynchronous operation implementation,
+ // - the completion token,
+ // - the completion handler signature, and
+ // - any I/O objects (or executors) used by the operation
+ //
+ // It then wraps our implementation, which is implemented here as a state
+ // machine in a lambda, in an intermediate completion handler that meets the
+ // requirements of a conforming asynchronous operation. This includes
+ // tracking outstanding work against the I/O executors associated with the
+ // operation (in this example, this is the socket's executor).
+ //
+ // The first argument to our lambda is a reference to the enclosing
+ // intermediate completion handler. This intermediate completion handler is
+ // provided for us by the asio::async_compose function, and takes care
+ // of all the details required to implement a conforming asynchronous
+ // operation. When calling an underlying asynchronous operation, we pass it
+ // this enclosing intermediate completion handler as the completion token.
+ //
+ // All arguments to our lambda after the first must be defaulted to allow the
+ // state machine to be started, as well as to allow the completion handler to
+ // match the completion signature of both the async_write and
+ // steady_timer::async_wait operations.
+ return asio::async_compose<
+ CompletionToken, void(std::error_code)>(
+ [
+ // The implementation holds a reference to the socket as it is used for
+ // multiple async_write operations.
+ &socket,
+
+ // The allocated buffer for the encoded message. The std::unique_ptr
+ // smart pointer is move-only, and as a consequence our lambda
+ // implementation is also move-only.
+ encoded_message = std::move(encoded_message),
+
+ // The repeat count remaining.
+ repeat_count,
+
+ // A steady timer used for introducing a delay.
+ delay_timer = std::move(delay_timer),
+
+ // To manage the cycle between the multiple underlying asychronous
+ // operations, our implementation is a state machine.
+ state = starting
+ ]
+ (
+ auto& self,
+ const std::error_code& error = {},
+ std::size_t = 0
+ ) mutable
+ {
+ if (!error)
+ {
+ switch (state)
+ {
+ case starting:
+ case writing:
+ if (repeat_count > 0)
+ {
+ --repeat_count;
+ state = waiting;
+ delay_timer->expires_after(std::chrono::seconds(1));
+ delay_timer->async_wait(std::move(self));
+ return; // Composed operation not yet complete.
+ }
+ break; // Composed operation complete, continue below.
+ case waiting:
+ state = writing;
+ asio::async_write(socket,
+ asio::buffer(*encoded_message), std::move(self));
+ return; // Composed operation not yet complete.
+ }
+ }
+
+ // This point is reached only on completion of the entire composed
+ // operation.
+
+ // Deallocate the encoded message and delay timer before calling the
+ // user-supplied completion handler.
+ encoded_message.reset();
+ delay_timer.reset();
+
+ // Call the user-supplied handler with the result of the operation.
+ self.complete(error);
+ },
+ token, socket);
+}
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_messages(socket, "Testing callback\r\n", 5,
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Messages sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_messages(socket,
+ "Testing deferred\r\n", 5, asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Messages sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<void> f = async_write_messages(
+ socket, "Testing future\r\n", 5, asio::use_future);
+
+ io_context.run();
+
+ try
+ {
+ // Get the result of the operation.
+ f.get();
+ std::cout << "Messages sent\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Error: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}
diff --git a/3rdparty/asio/src/examples/cpp14/operations/composed_8.cpp b/3rdparty/asio/src/examples/cpp14/operations/composed_8.cpp
new file mode 100644
index 00000000000..d1f46ddce54
--- /dev/null
+++ b/3rdparty/asio/src/examples/cpp14/operations/composed_8.cpp
@@ -0,0 +1,254 @@
+//
+// composed_8.cpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2024 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)
+//
+
+#include <asio/compose.hpp>
+#include <asio/coroutine.hpp>
+#include <asio/deferred.hpp>
+#include <asio/io_context.hpp>
+#include <asio/ip/tcp.hpp>
+#include <asio/steady_timer.hpp>
+#include <asio/use_future.hpp>
+#include <asio/write.hpp>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+using asio::ip::tcp;
+
+// NOTE: This example requires the new asio::async_compose function. For
+// an example that works with the Networking TS style of completion tokens,
+// please see an older version of asio.
+
+//------------------------------------------------------------------------------
+
+// This composed operation shows composition of multiple underlying operations,
+// using asio's stackless coroutines support to express the flow of control. It
+// automatically serialises a message, using its I/O streams insertion
+// operator, before sending it N times on the socket. To do this, it must
+// allocate a buffer for the encoded message and ensure this buffer's validity
+// until all underlying async_write operation complete. A one second delay is
+// inserted prior to each write operation, using a steady_timer.
+
+#include <asio/yield.hpp>
+
+template <typename T, typename CompletionToken>
+auto async_write_messages(tcp::socket& socket,
+ const T& message, std::size_t repeat_count,
+ CompletionToken&& token)
+ // The return type of the initiating function is deduced from the combination
+ // of:
+ //
+ // - the CompletionToken type,
+ // - the completion handler signature, and
+ // - the asynchronous operation's initiation function object.
+ //
+ // When the completion token is a simple callback, the return type is always
+ // void. In this example, when the completion token is asio::yield_context
+ // (used for stackful coroutines) the return type would also be void, as
+ // there is no non-error argument to the completion handler. When the
+ // completion token is asio::use_future it would be std::future<void>. When
+ // the completion token is asio::deferred, the return type differs for each
+ // asynchronous operation.
+ //
+ // In C++14 we can omit the return type as it is automatically deduced from
+ // the return type of asio::async_compose.
+{
+ // Encode the message and copy it into an allocated buffer. The buffer will
+ // be maintained for the lifetime of the composed asynchronous operation.
+ std::ostringstream os;
+ os << message;
+ std::unique_ptr<std::string> encoded_message(new std::string(os.str()));
+
+ // Create a steady_timer to be used for the delay between messages.
+ std::unique_ptr<asio::steady_timer> delay_timer(
+ new asio::steady_timer(socket.get_executor()));
+
+ // The asio::async_compose function takes:
+ //
+ // - our asynchronous operation implementation,
+ // - the completion token,
+ // - the completion handler signature, and
+ // - any I/O objects (or executors) used by the operation
+ //
+ // It then wraps our implementation, which is implemented here as a stackless
+ // coroutine in a lambda, in an intermediate completion handler that meets the
+ // requirements of a conforming asynchronous operation. This includes
+ // tracking outstanding work against the I/O executors associated with the
+ // operation (in this example, this is the socket's executor).
+ //
+ // The first argument to our lambda is a reference to the enclosing
+ // intermediate completion handler. This intermediate completion handler is
+ // provided for us by the asio::async_compose function, and takes care
+ // of all the details required to implement a conforming asynchronous
+ // operation. When calling an underlying asynchronous operation, we pass it
+ // this enclosing intermediate completion handler as the completion token.
+ //
+ // All arguments to our lambda after the first must be defaulted to allow the
+ // state machine to be started, as well as to allow the completion handler to
+ // match the completion signature of both the async_write and
+ // steady_timer::async_wait operations.
+ return asio::async_compose<
+ CompletionToken, void(std::error_code)>(
+ [
+ // The implementation holds a reference to the socket as it is used for
+ // multiple async_write operations.
+ &socket,
+
+ // The allocated buffer for the encoded message. The std::unique_ptr
+ // smart pointer is move-only, and as a consequence our lambda
+ // implementation is also move-only.
+ encoded_message = std::move(encoded_message),
+
+ // The repeat count remaining.
+ repeat_count,
+
+ // A steady timer used for introducing a delay.
+ delay_timer = std::move(delay_timer),
+
+ // The coroutine state.
+ coro = asio::coroutine()
+ ]
+ (
+ auto& self,
+ const std::error_code& error = {},
+ std::size_t = 0
+ ) mutable
+ {
+ reenter (coro)
+ {
+ while (repeat_count > 0)
+ {
+ --repeat_count;
+
+ delay_timer->expires_after(std::chrono::seconds(1));
+ yield delay_timer->async_wait(std::move(self));
+ if (error)
+ break;
+
+ yield asio::async_write(socket,
+ asio::buffer(*encoded_message), std::move(self));
+ if (error)
+ break;
+ }
+
+ // Deallocate the encoded message and delay timer before calling the
+ // user-supplied completion handler.
+ encoded_message.reset();
+ delay_timer.reset();
+
+ // Call the user-supplied handler with the result of the operation.
+ self.complete(error);
+ }
+ },
+ token, socket);
+}
+
+#include <asio/unyield.hpp>
+
+//------------------------------------------------------------------------------
+
+void test_callback()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using a lambda as a callback.
+ async_write_messages(socket, "Testing callback\r\n", 5,
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Messages sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_deferred()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the deferred completion token. This
+ // token causes the operation's initiating function to package up the
+ // operation with its arguments to return a function object, which may then be
+ // used to launch the asynchronous operation.
+ auto op = async_write_messages(socket,
+ "Testing deferred\r\n", 5, asio::deferred);
+
+ // Launch the operation using a lambda as a callback.
+ std::move(op)(
+ [](const std::error_code& error)
+ {
+ if (!error)
+ {
+ std::cout << "Messages sent\n";
+ }
+ else
+ {
+ std::cout << "Error: " << error.message() << "\n";
+ }
+ });
+
+ io_context.run();
+}
+
+//------------------------------------------------------------------------------
+
+void test_future()
+{
+ asio::io_context io_context;
+
+ tcp::acceptor acceptor(io_context, {tcp::v4(), 55555});
+ tcp::socket socket = acceptor.accept();
+
+ // Test our asynchronous operation using the use_future completion token.
+ // This token causes the operation's initiating function to return a future,
+ // which may be used to synchronously wait for the result of the operation.
+ std::future<void> f = async_write_messages(
+ socket, "Testing future\r\n", 5, asio::use_future);
+
+ io_context.run();
+
+ try
+ {
+ // Get the result of the operation.
+ f.get();
+ std::cout << "Messages sent\n";
+ }
+ catch (const std::exception& e)
+ {
+ std::cout << "Error: " << e.what() << "\n";
+ }
+}
+
+//------------------------------------------------------------------------------
+
+int main()
+{
+ test_callback();
+ test_deferred();
+ test_future();
+}