Base implementation of an ASIO completion token integration

* Bump the asio version to 1.41
* Move headers that require an external dependency to include/continuable/support
* Ref #28
* Ref #27

dep/asio/asio

@@ -1 +1 @@
-Subproject commit 0a52abce85ab83b920cc7257d8a2703fe69bc79c
+Subproject commit 8087252a0c3c2f0baad96ddbd6554db17a846376

doc/installation.dox

@@ -49,7 +49,7 @@ Continuable is a header-only library with one required header-only dependency:
     erasure wrapper to convert a \ref continuable_base into a \ref continuable.
 
 Additionally GTest is required as optional dependency for the asynchronous
-unit testing macros defined in `continuable/continuable-testing.hpp`
+unit testing macros defined in `continuable/support/gtest.hpp`
 if those are used:
 
   - [google/googletest](https://github.com/google/googletest) is used as

examples/example-asio/CMakeLists.txt

@@ -1,15 +1,28 @@
+add_library(asio-example-deps INTERFACE)
+
+target_include_directories(asio-example-deps
+  INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR})
+
+target_link_libraries(asio-example-deps
+  INTERFACE
+    asio
+    continuable)
+
 add_executable(example-asio
     ${CMAKE_CURRENT_LIST_DIR}/example-asio.cpp)
 
-target_include_directories(example-asio
-  PRIVATE
-    ${CMAKE_CURRENT_LIST_DIR})
-
 target_link_libraries(example-asio
   PRIVATE
-    asio
-    continuable)
+    asio-example-deps)
 
 target_compile_definitions(example-asio
   PUBLIC
     -DCONTINUABLE_WITH_NO_EXCEPTIONS)
+
+add_executable(example-asio-integration
+    ${CMAKE_CURRENT_LIST_DIR}/example-asio-integration.cpp)
+
+target_link_libraries(example-asio-integration
+  PRIVATE
+    asio-example-deps)

examples/example-asio/example-asio-integration.cpp

@@ -0,0 +1,129 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#include <asio.hpp>
+
+#include <continuable/continuable.hpp>
+#include <continuable/support/asio.hpp>
+
+// Queries the NIST daytime service and prints the current date and time
+void daytime_service();
+
+// Checks that a cancelled timer async_wait fails with
+// `asio::error::operation_aborted`
+void cancelled_async_wait();
+
+// Indicates fatal error due to an unexpected failure in the continuation chain.
+void unexpected_error(cti::exception_t);
+
+// Check that the failure was an aborted operation, as expected.
+void check_aborted_operation(cti::exception_t);
+
+int main(int, char**) {
+  daytime_service();
+  cancelled_async_wait();
+
+  return 0;
+}
+
+void daytime_service() {
+  using asio::ip::tcp;
+
+  asio::io_context ioc(1);
+  tcp::resolver resolver(ioc);
+  tcp::socket socket(ioc);
+  std::string buf;
+
+  resolver.async_resolve("time.nist.gov", "daytime", cti::asio_token)
+      .then([&socket](tcp::resolver::results_type endpoints) {
+        return asio::async_connect(socket, endpoints, cti::asio_token);
+      })
+      .then([&socket, &buf] {
+        return asio::async_read_until(socket, asio::dynamic_buffer(buf), '\n',
+                                      cti::asio_token);
+      })
+      .then([&buf](std::size_t) { puts(buf.data()); })
+      .fail(&unexpected_error);
+
+  ioc.run();
+}
+
+void cancelled_async_wait() {
+  asio::io_context ioc(1);
+  asio::steady_timer t(ioc);
+
+  t.expires_after(std::chrono::seconds(999));
+
+  t.async_wait(cti::asio_token)
+      .then([] {
+        puts("This should never be called");
+        std::terminate();
+      })
+      .fail(&check_aborted_operation);
+
+  t.cancel_one();
+  ioc.run();
+}
+
+void unexpected_error(cti::exception_t e) {
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+  std::rethrow_exception(e);
+#else
+  puts("Continuation failed with unexpected error");
+  puts(e.message().data());
+  std::terminate();
+#endif
+}
+
+void check_aborted_operation(cti::exception_t ex) {
+  auto is_expected_error = [](auto err_val) {
+    if (err_val == asio::error_code(asio::error::operation_aborted)) {
+      puts("Continuation failed due to aborted async operation, as expected.");
+      return true;
+    }
+    return false;
+  };
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+  try {
+    std::rethrow_exception(ex);
+  } catch (asio::system_error const& err) {
+    if (is_expected_error(err.code())) {
+      return;
+    }
+  }
+#else
+  if (is_expected_error(ex)) {
+    return;
+  }
+#endif
+
+  unexpected_error(ex);
+}

examples/example-asio/example-asio.cpp

@@ -5,7 +5,7 @@
                         \_,(_)| | | || ||_|(_||_)|(/_
 
                     https://github.com/Naios/continuable
-                                   v3.0.0
+                                   v4.0.0
 
   Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
 

include/continuable/detail/support/asio.hpp

@@ -0,0 +1,154 @@
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_ASIO_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_ASIO_HPP_INCLUDED
+
+#include <continuable/detail/features.hpp>
+
+#if defined(ASIO_STANDALONE)
+#include <asio/async_result.hpp>
+#include <asio/error_code.hpp>
+#include <asio/version.hpp>
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#include <asio/system_error.hpp>
+#endif
+
+#if (ASIO_VERSION / 100 % 1000) <= 12
+#define CTI_DETAIL_ASIO_HAS_NO_INTEGRATION
+#elif (ASIO_VERSION / 100 % 1000) <= 14
+#define CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION
+#endif
+
+#define CTI_DETAIL_ASIO_NAMESPACE_BEGIN namespace asio {
+#define CTI_DETAIL_ASIO_NAMESPACE_END }
+#else
+#include <boost/asio/async_result.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/version.hpp>
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#include <boost/system/system_error.hpp>
+#endif
+
+#if (BOOST_VERSION / 100 % 1000) <= 69
+#define CTI_DETAIL_ASIO_HAS_NO_INTEGRATION
+#elif (BOOST_VERSION / 100 % 1000) <= 71
+#define CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION
+#endif
+
+#define CTI_DETAIL_ASIO_NAMESPACE_BEGIN                                        \
+  namespace boost {                                                            \
+  namespace asio {
+#define CTI_DETAIL_ASIO_NAMESPACE_END                                          \
+  }                                                                            \
+  }
+#endif
+
+#if defined(CTI_DETAIL_ASIO_HAS_NO_INTEGRATION)
+#error "First-class ASIO support for continuable requires the form of "\
+  "`async_result` with an `initiate` static member function, which was added " \
+  "in standalone ASIO 1.13.0 and Boost ASIO 1.70. Older versions can be " \
+  "integrated manually with `cti::promisify`."
+#endif
+
+#include <continuable/detail/core/base.hpp>
+
+#include <utility>
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+#include <exception>
+#endif
+
+namespace cti {
+namespace detail {
+namespace asio {
+
+#if defined(ASIO_STANDALONE)
+using error_code_t = ::asio::error_code;
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+using system_error_t = ::asio::system_error;
+#endif
+#else
+using error_code_t = ::boost::system::error_code;
+
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+using system_error_t = ::boost::system::system_error;
+#endif
+#endif
+
+// Binds `promise` to the first argument of a continuable resolver, giving it
+// the signature of an ASIO handler.
+template <typename Promise>
+auto promise_resolver_handler(Promise&& promise) noexcept {
+  return [promise = std::forward<Promise>(promise)](
+             error_code_t e, auto&&... args) mutable noexcept {
+    if (e) {
+#if defined(CONTINUABLE_HAS_EXCEPTIONS)
+      promise.set_exception(
+          std::make_exception_ptr(system_error_t(std::move(e))));
+#else
+      promise.set_exception(cti::exception_t(e.value(), e.category()));
+#endif
+    } else {
+      promise.set_value(std::forward<decltype(args)>(args)...);
+    }
+  };
+}
+
+// Helper struct wrapping a call to `cti::make_continuable` and, if needed,
+// providing an erased, explicit `return_type` for `async_result`.
+template <typename Signature>
+struct initiate_make_continuable;
+
+template <typename... Args>
+struct initiate_make_continuable<void(error_code_t, Args...)> {
+#if defined(CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION)
+  using erased_return_type = cti::continuable<Args...>;
+#endif
+
+  template <typename Continuation>
+  auto operator()(Continuation&& continuation) {
+    return detail::base::attorney::create_from(
+        std::forward<Continuation>(continuation), detail::identity<Args...>{},
+        detail::util::ownership{});
+  }
+};
+
+template <typename... Args>
+struct initiate_make_continuable<void(error_code_t const&, Args...)>
+    : initiate_make_continuable<void(error_code_t, Args...)> {};
+
+} // namespace asio
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_ASIO_HPP_INCLUDED

include/continuable/support/asio.hpp

@@ -0,0 +1,83 @@
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_SUPPORT_ASIO_HPP_INCLUDED
+#define CONTINUABLE_SUPPORT_ASIO_HPP_INCLUDED
+
+#include <continuable/continuable-base.hpp>
+#include <continuable/detail/support/asio.hpp>
+#include <continuable/detail/utility/traits.hpp>
+
+namespace cti {
+
+// Type used as an ASIO completion token to specify an asynchronous operation
+// should return a continuable.
+struct asio_token_t {};
+
+// Special value for instance of `asio_token_t`.
+constexpr asio_token_t asio_token{};
+
+} // namespace cti
+
+CTI_DETAIL_ASIO_NAMESPACE_BEGIN
+
+template <typename Signature>
+class async_result<cti::asio_token_t, Signature> {
+public:
+#if defined(CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION)
+  using return_type = typename cti::detail::asio::initiate_make_continuable<
+      Signature>::erased_return_type;
+#endif
+
+  template <typename Initiation, typename... Args>
+  static auto initiate(Initiation initiation, cti::asio_token_t, Args... args) {
+    return cti::detail::asio::initiate_make_continuable<Signature>{}(
+        [initiation = std::move(initiation),
+         init_args =
+             std::make_tuple(std::move(args)...)](auto&& promise) mutable {
+          cti::detail::traits::unpack(
+              [initiation = std::move(initiation),
+               handler = cti::detail::asio::promise_resolver_handler(
+                   std::forward<decltype(promise)>(promise))](
+                  auto&&... args) mutable {
+                std::move(initiation)(std::move(handler),
+                                      std::forward<decltype(args)>(args)...);
+              },
+              std::move(init_args));
+        });
+  }
+};
+
+CTI_DETAIL_ASIO_NAMESPACE_END
+
+#undef CTI_DETAIL_ASIO_NAMESPACE_BEGIN
+#undef CTI_DETAIL_ASIO_NAMESPACE_END
+#undef CTI_DETAIL_ASIO_HAS_EXPLICIT_RET_TYPE_INTEGRATION
+
+#endif // CONTINUABLE_SUPPORT_ASIO_HPP_INCLUDED

include/continuable/support/gtest.hpp

@@ -28,8 +28,8 @@
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_TESTING_HPP_INCLUDED
-#define CONTINUABLE_TESTING_HPP_INCLUDED
+#ifndef CONTINUABLE_SUPPORT_GTEST_HPP_INCLUDED
+#define CONTINUABLE_SUPPORT_GTEST_HPP_INCLUDED
 
 #include <continuable/detail/other/testing.hpp>
 #include <continuable/detail/utility/traits.hpp>
@@ -169,4 +169,4 @@
 
 /// \}
 
-#endif // CONTINUABLE_TESTING_HPP_INCLUDED
+#endif // CONTINUABLE_SUPPORT_GTEST_HPP_INCLUDED

test/unit-test/test-continuable.hpp

@@ -31,8 +31,8 @@
 #include <functional>
 
 #include <continuable/continuable-base.hpp>
-#include <continuable/continuable-testing.hpp>
 #include <continuable/continuable.hpp>
+#include <continuable/support/gtest.hpp>
 #include <string>
 
 using cti::detail::identity;