comparison third_party/boost/process/handle.hpp @ 0:add35537fdbb tip

Initial import

+//
+// Boost.Process
+// ~~~~~~~~~~~~~
+//
+// 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
+//
+// 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/handle.hpp
+ *
+ * Includes the declaration of the handle class.
+ */
+
+#ifndef BOOST_PROCESS_HANDLE_HPP
+#define BOOST_PROCESS_HANDLE_HPP
+
+#include <boost/process/config.hpp>
+
+#if defined(BOOST_POSIX_API)
+#   include <unistd.h>
+#elif defined(BOOST_WINDOWS_API)
+#   include <windows.h>
+#else
+#   error "Unsupported platform."
+#endif
+
+#include <boost/shared_ptr.hpp>
+#include <boost/make_shared.hpp>
+
+namespace boost {
+namespace process {
+
+/**
+ * RAII model for handles.
+ *
+ * The \a handle class is a RAII model for native handles. This class wraps
+ * one of such handles grabbing its ownership, and automaticaly closes it
+ * upon destruction. It is used to avoid leaking open handles, shall an
+ * unexpected execution trace occur.
+ */
+class handle
+{
+public:
+#if defined(BOOST_PROCESS_DOXYGEN)
+    /**
+     * Opaque name for the native handle type.
+     *
+     * On POSIX systems \a NativeSystemHandle is an integer type while it is
+     * a \a HANDLE on Windows systems.
+     */
+    typedef NativeSystemHandle native_type;
+#elif defined(BOOST_POSIX_API)
+    typedef int native_type;
+#elif defined(BOOST_WINDOWS_API)
+    typedef HANDLE native_type;
+#endif
+
+    /**
+     * Constructs an invalid handle.
+     *
+     * \see valid()
+     */
+    handle()
+    {
+    }
+
+    /**
+     * RAII settings to specify if handle should be automatically closed.
+     */
+    enum close_type { do_close, dont_close };
+
+    /**
+     * Constructs a handle from a native handle.
+     *
+     * This constructor creates a new \a handle object that takes
+     * ownership of the given \a native handle. If \a close is set to
+     * handle::dont_close the \a native handle is not closed upon destruction.
+     * The user must not close \a native if it is owned by a \a handle object.
+     * Ownership can be reclaimed using release().
+     *
+     * \see release()
+     */
+    handle(native_type native, close_type close = handle::do_close)
+    : impl_(boost::make_shared<impl>(native, close))
+    {
+    }
+
+    /**
+     * Checks whether the handle is valid or not.
+     *
+     * \return true if the handle is valid; false otherwise.
+     */
+    bool valid() const
+    {
+        return impl_ && impl_->valid();
+    }
+
+    /**
+     * Closes the handle.
+     *
+     * \post The handle is invalid.
+     * \post The native handle is closed.
+     */
+    void close()
+    {
+        if (impl_)
+            impl_->close();
+    }
+
+    /**
+     * Gets the native handle.
+     *
+     * The caller can issue any operation on it except closing it.
+     * If closing is required, release() shall be used.
+     *
+     * \return The native handle.
+     */
+    native_type native() const
+    {
+        return impl_ ? impl_->native() : invalid_handle();
+    }
+
+    /**
+     * Reclaims ownership of the native handle.
+     *
+     * The caller is responsible of closing the native handle.
+     *
+     * \post The handle is invalid.
+     * \return The native handle.
+     */
+    native_type release()
+    {
+        return impl_ ? impl_->release() : invalid_handle();
+    }
+
+private:
+    class impl
+    {
+    public:
+        typedef handle::native_type native_type;
+
+        impl(native_type native, close_type close)
+        : native_(native),
+        close_(close)
+        {
+        }
+
+        ~impl()
+        {
+            if (valid() && close_ == handle::do_close)
+            {
+#if defined(BOOST_POSIX_API)
+                ::close(native_);
+#elif defined(BOOST_WINDOWS_API)
+                CloseHandle(native_);
+#endif
+            }
+        }
+
+        bool valid() const
+        {
+            return native_ != handle::invalid_handle();
+        }
+
+        void close()
+        {
+            if (valid())
+            {
+#if defined(BOOST_POSIX_API)
+                ::close(native_);
+#elif defined(BOOST_WINDOWS_API)
+                CloseHandle(native_);
+#endif
+                native_ = handle::invalid_handle();
+            }
+        }
+
+        native_type native() const
+        {
+            return native_;
+        }
+
+        native_type release()
+        {
+            native_type native = native_;
+            native_ = handle::invalid_handle();
+            return native;
+        }
+
+    private:
+        native_type native_;
+        close_type close_;
+    };
+
+    /**
+     * Implementation of handle to store native handle value.
+     *
+     * A shared pointer is used as handles represent system resources. If a
+     * handle is closed and becomes invalid the state of copies of the handle
+     * object will be updated as they all share the handle implementation.
+     */
+    boost::shared_ptr<impl> impl_;
+
+    /**
+     * Constant function representing an invalid handle value.
+     *
+     * Returns the platform-specific handle value that represents an
+     * invalid handle. This is a constant function rather than a regular
+     * constant because, in the latter case, we cannot define it under
+     * Windows due to the value being of a complex type.
+     */
+    static const native_type invalid_handle()
+    {
+#if defined(BOOST_POSIX_API)
+        return -1;
+#elif defined(BOOST_WINDOWS_API)
+        return INVALID_HANDLE_VALUE;
+#endif
+    }
+};
+
+}
+}
+
+#endif