整理

include/boost/process/v1/system.hpp

@@ -0,0 +1,158 @@
+// Copyright (c) 2006, 2007 Julio M. Merino Vidal
+// Copyright (c) 2008 Ilya Sokolov, Boris Schaeling
+// Copyright (c) 2009 Boris Schaeling
+// Copyright (c) 2010 Felipe Tanus, Boris Schaeling
+// Copyright (c) 2011, 2012 Jeff Flinn, Boris Schaeling
+// Copyright (c) 2016 Klemens D. Morgenstern
+//
+// 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)
+
+/**
+ * \file boost/process/system.hpp
+ *
+ * Defines a system function.
+ */
+
+#ifndef BOOST_PROCESS_SYSTEM_HPP
+#define BOOST_PROCESS_SYSTEM_HPP
+
+#include <boost/process/v1/detail/config.hpp>
+#include <boost/process/v1/detail/on_exit.hpp>
+#include <boost/process/v1/child.hpp>
+#include <boost/process/v1/detail/async_handler.hpp>
+#include <boost/process/v1/detail/execute_impl.hpp>
+#include <boost/asio/post.hpp>
+#include <type_traits>
+#include <mutex>
+#include <condition_variable>
+
+#if defined(BOOST_POSIX_API)
+#include <boost/process/v1/posix.hpp>
+#endif
+
+namespace boost {
+
+namespace process { BOOST_PROCESS_V1_INLINE namespace v1 {
+
+namespace detail
+{
+
+struct system_impl_success_check : handler
+{
+    bool succeeded = false;
+
+    template<typename Exec>
+    void on_success(Exec &) { succeeded = true; }
+};
+
+template<typename IoService, typename ...Args>
+inline int system_impl(
+        std::true_type, /*needs ios*/
+        std::true_type, /*has io_context*/
+        Args && ...args)
+{
+    IoService & ios = ::boost::process::v1::detail::get_io_context_var(args...);
+
+    system_impl_success_check check;
+
+    std::atomic_bool exited{false};
+
+    child c(std::forward<Args>(args)...,
+            check,
+            ::boost::process::v1::on_exit(
+                [&](int, const std::error_code&)
+                {
+                    boost::asio::post(ios.get_executor(), [&]{exited.store(true);});
+                }));
+    if (!c.valid() || !check.succeeded)
+        return -1;
+
+    while (!exited.load())
+        ios.poll();
+
+    return c.exit_code();
+}
+
+template<typename IoService, typename ...Args>
+inline int system_impl(
+        std::true_type,  /*needs ios */
+        std::false_type, /*has io_context*/
+        Args && ...args)
+{
+    IoService ios;
+    child c(ios, std::forward<Args>(args)...);
+    if (!c.valid())
+        return -1;
+
+    ios.run();
+    if (c.running())
+        c.wait();
+    return c.exit_code();
+}
+
+
+template<typename IoService, typename ...Args>
+inline int system_impl(
+        std::false_type, /*needs ios*/
+        std::true_type, /*has io_context*/
+        Args && ...args)
+{
+    child c(std::forward<Args>(args)...);
+    if (!c.valid())
+        return -1;
+    c.wait();
+    return c.exit_code();
+}
+
+template<typename IoService, typename ...Args>
+inline int system_impl(
+        std::false_type, /*has async */
+        std::false_type, /*has io_context*/
+        Args && ...args)
+{
+    child c(std::forward<Args>(args)...
+#if defined(BOOST_POSIX_API)
+            ,::boost::process::v1::posix::sig.dfl()
+#endif
+            );
+    if (!c.valid())
+        return -1;
+    c.wait();
+    return c.exit_code();
+}
+
+}
+
+/** Launches a process and waits for its exit.
+It works as std::system, though it allows
+all the properties boost.process provides. It will execute the process and wait for it's exit; then return the exit_code.
+
+\code{.cpp}
+int ret = system("ls");
+\endcode
+
+\attention Using this function with synchronous pipes leads to many potential deadlocks.
+
+When using this function with an asynchronous properties and NOT passing an io_context object,
+the system function will create one and run it. When the io_context is passed to the function,
+the system function will check if it is active, and call the io_context::run function if not.
+
+*/
+template<typename ...Args>
+inline int system(Args && ...args)
+{
+    typedef typename ::boost::process::v1::detail::needs_io_context<Args...>::type
+            need_ios;
+    typedef typename ::boost::process::v1::detail::has_io_context<Args...>::type
+            has_ios;
+    return ::boost::process::v1::detail::system_impl<boost::asio::io_context>(
+            need_ios(), has_ios(),
+            std::forward<Args>(args)...);
+}
+
+
+}}}
+
+#endif
+