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+//
+// detail/impl/descriptor_ops.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
+#define ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cerrno>
+#include "asio/detail/descriptor_ops.hpp"
+#include "asio/error.hpp"
+
+#if !defined(ASIO_WINDOWS) \
+ && !defined(ASIO_WINDOWS_RUNTIME) \
+ && !defined(__CYGWIN__)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace descriptor_ops {
+
+int open(const char* path, int flags, asio::error_code& ec)
+{
+ errno = 0;
+ int result = error_wrapper(::open(path, flags), ec);
+ if (result >= 0)
+ ec = asio::error_code();
+ return result;
+}
+
+int close(int d, state_type& state, asio::error_code& ec)
+{
+ int result = 0;
+ if (d != -1)
+ {
+ errno = 0;
+ result = error_wrapper(::close(d), ec);
+
+ if (result != 0
+ && (ec == asio::error::would_block
+ || ec == asio::error::try_again))
+ {
+ // According to UNIX Network Programming Vol. 1, it is possible for
+ // close() to fail with EWOULDBLOCK under certain circumstances. What
+ // isn't clear is the state of the descriptor after this error. The one
+ // current OS where this behaviour is seen, Windows, says that the socket
+ // remains open. Therefore we'll put the descriptor back into blocking
+ // mode and have another attempt at closing it.
+#if defined(__SYMBIAN32__)
+ int flags = ::fcntl(d, F_GETFL, 0);
+ if (flags >= 0)
+ ::fcntl(d, F_SETFL, flags & ~O_NONBLOCK);
+#else // defined(__SYMBIAN32__)
+ ioctl_arg_type arg = 0;
+ ::ioctl(d, FIONBIO, &arg);
+#endif // defined(__SYMBIAN32__)
+ state &= ~non_blocking;
+
+ errno = 0;
+ result = error_wrapper(::close(d), ec);
+ }
+ }
+
+ if (result == 0)
+ ec = asio::error_code();
+ return result;
+}
+
+bool set_user_non_blocking(int d, state_type& state,
+ bool value, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return false;
+ }
+
+ errno = 0;
+#if defined(__SYMBIAN32__)
+ int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
+ if (result >= 0)
+ {
+ errno = 0;
+ int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
+ result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
+ }
+#else // defined(__SYMBIAN32__)
+ ioctl_arg_type arg = (value ? 1 : 0);
+ int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
+#endif // defined(__SYMBIAN32__)
+
+ if (result >= 0)
+ {
+ ec = asio::error_code();
+ if (value)
+ state |= user_set_non_blocking;
+ else
+ {
+ // Clearing the user-set non-blocking mode always overrides any
+ // internally-set non-blocking flag. Any subsequent asynchronous
+ // operations will need to re-enable non-blocking I/O.
+ state &= ~(user_set_non_blocking | internal_non_blocking);
+ }
+ return true;
+ }
+
+ return false;
+}
+
+bool set_internal_non_blocking(int d, state_type& state,
+ bool value, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return false;
+ }
+
+ if (!value && (state & user_set_non_blocking))
+ {
+ // It does not make sense to clear the internal non-blocking flag if the
+ // user still wants non-blocking behaviour. Return an error and let the
+ // caller figure out whether to update the user-set non-blocking flag.
+ ec = asio::error::invalid_argument;
+ return false;
+ }
+
+ errno = 0;
+#if defined(__SYMBIAN32__)
+ int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
+ if (result >= 0)
+ {
+ errno = 0;
+ int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
+ result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
+ }
+#else // defined(__SYMBIAN32__)
+ ioctl_arg_type arg = (value ? 1 : 0);
+ int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
+#endif // defined(__SYMBIAN32__)
+
+ if (result >= 0)
+ {
+ ec = asio::error_code();
+ if (value)
+ state |= internal_non_blocking;
+ else
+ state &= ~internal_non_blocking;
+ return true;
+ }
+
+ return false;
+}
+
+std::size_t sync_read(int d, state_type state, buf* bufs,
+ std::size_t count, bool all_empty, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return 0;
+ }
+
+ // A request to read 0 bytes on a stream is a no-op.
+ if (all_empty)
+ {
+ ec = asio::error_code();
+ return 0;
+ }
+
+ // Read some data.
+ for (;;)
+ {
+ // Try to complete the operation without blocking.
+ errno = 0;
+ signed_size_type bytes = error_wrapper(::readv(
+ d, bufs, static_cast<int>(count)), ec);
+
+ // Check if operation succeeded.
+ if (bytes > 0)
+ return bytes;
+
+ // Check for EOF.
+ if (bytes == 0)
+ {
+ ec = asio::error::eof;
+ return 0;
+ }
+
+ // Operation failed.
+ if ((state & user_set_non_blocking)
+ || (ec != asio::error::would_block
+ && ec != asio::error::try_again))
+ return 0;
+
+ // Wait for descriptor to become ready.
+ if (descriptor_ops::poll_read(d, 0, ec) < 0)
+ return 0;
+ }
+}
+
+bool non_blocking_read(int d, buf* bufs, std::size_t count,
+ asio::error_code& ec, std::size_t& bytes_transferred)
+{
+ for (;;)
+ {
+ // Read some data.
+ errno = 0;
+ signed_size_type bytes = error_wrapper(::readv(
+ d, bufs, static_cast<int>(count)), ec);
+
+ // Check for end of stream.
+ if (bytes == 0)
+ {
+ ec = asio::error::eof;
+ return true;
+ }
+
+ // Retry operation if interrupted by signal.
+ if (ec == asio::error::interrupted)
+ continue;
+
+ // Check if we need to run the operation again.
+ if (ec == asio::error::would_block
+ || ec == asio::error::try_again)
+ return false;
+
+ // Operation is complete.
+ if (bytes > 0)
+ {
+ ec = asio::error_code();
+ bytes_transferred = bytes;
+ }
+ else
+ bytes_transferred = 0;
+
+ return true;
+ }
+}
+
+std::size_t sync_write(int d, state_type state, const buf* bufs,
+ std::size_t count, bool all_empty, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return 0;
+ }
+
+ // A request to write 0 bytes on a stream is a no-op.
+ if (all_empty)
+ {
+ ec = asio::error_code();
+ return 0;
+ }
+
+ // Write some data.
+ for (;;)
+ {
+ // Try to complete the operation without blocking.
+ errno = 0;
+ signed_size_type bytes = error_wrapper(::writev(
+ d, bufs, static_cast<int>(count)), ec);
+
+ // Check if operation succeeded.
+ if (bytes > 0)
+ return bytes;
+
+ // Operation failed.
+ if ((state & user_set_non_blocking)
+ || (ec != asio::error::would_block
+ && ec != asio::error::try_again))
+ return 0;
+
+ // Wait for descriptor to become ready.
+ if (descriptor_ops::poll_write(d, 0, ec) < 0)
+ return 0;
+ }
+}
+
+bool non_blocking_write(int d, const buf* bufs, std::size_t count,
+ asio::error_code& ec, std::size_t& bytes_transferred)
+{
+ for (;;)
+ {
+ // Write some data.
+ errno = 0;
+ signed_size_type bytes = error_wrapper(::writev(
+ d, bufs, static_cast<int>(count)), ec);
+
+ // Retry operation if interrupted by signal.
+ if (ec == asio::error::interrupted)
+ continue;
+
+ // Check if we need to run the operation again.
+ if (ec == asio::error::would_block
+ || ec == asio::error::try_again)
+ return false;
+
+ // Operation is complete.
+ if (bytes >= 0)
+ {
+ ec = asio::error_code();
+ bytes_transferred = bytes;
+ }
+ else
+ bytes_transferred = 0;
+
+ return true;
+ }
+}
+
+int ioctl(int d, state_type& state, long cmd,
+ ioctl_arg_type* arg, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return -1;
+ }
+
+ errno = 0;
+ int result = error_wrapper(::ioctl(d, cmd, arg), ec);
+
+ if (result >= 0)
+ {
+ ec = asio::error_code();
+
+ // When updating the non-blocking mode we always perform the ioctl syscall,
+ // even if the flags would otherwise indicate that the descriptor is
+ // already in the correct state. This ensures that the underlying
+ // descriptor is put into the state that has been requested by the user. If
+ // the ioctl syscall was successful then we need to update the flags to
+ // match.
+ if (cmd == static_cast<long>(FIONBIO))
+ {
+ if (*arg)
+ {
+ state |= user_set_non_blocking;
+ }
+ else
+ {
+ // Clearing the non-blocking mode always overrides any internally-set
+ // non-blocking flag. Any subsequent asynchronous operations will need
+ // to re-enable non-blocking I/O.
+ state &= ~(user_set_non_blocking | internal_non_blocking);
+ }
+ }
+ }
+
+ return result;
+}
+
+int fcntl(int d, int cmd, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return -1;
+ }
+
+ errno = 0;
+ int result = error_wrapper(::fcntl(d, cmd), ec);
+ if (result != -1)
+ ec = asio::error_code();
+ return result;
+}
+
+int fcntl(int d, int cmd, long arg, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return -1;
+ }
+
+ errno = 0;
+ int result = error_wrapper(::fcntl(d, cmd, arg), ec);
+ if (result != -1)
+ ec = asio::error_code();
+ return result;
+}
+
+int poll_read(int d, state_type state, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return -1;
+ }
+
+ pollfd fds;
+ fds.fd = d;
+ fds.events = POLLIN;
+ fds.revents = 0;
+ int timeout = (state & user_set_non_blocking) ? 0 : -1;
+ errno = 0;
+ int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+ if (result == 0)
+ ec = (state & user_set_non_blocking)
+ ? asio::error::would_block : asio::error_code();
+ else if (result > 0)
+ ec = asio::error_code();
+ return result;
+}
+
+int poll_write(int d, state_type state, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return -1;
+ }
+
+ pollfd fds;
+ fds.fd = d;
+ fds.events = POLLOUT;
+ fds.revents = 0;
+ int timeout = (state & user_set_non_blocking) ? 0 : -1;
+ errno = 0;
+ int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+ if (result == 0)
+ ec = (state & user_set_non_blocking)
+ ? asio::error::would_block : asio::error_code();
+ else if (result > 0)
+ ec = asio::error_code();
+ return result;
+}
+
+int poll_error(int d, state_type state, asio::error_code& ec)
+{
+ if (d == -1)
+ {
+ ec = asio::error::bad_descriptor;
+ return -1;
+ }
+
+ pollfd fds;
+ fds.fd = d;
+ fds.events = POLLPRI | POLLERR | POLLHUP;
+ fds.revents = 0;
+ int timeout = (state & user_set_non_blocking) ? 0 : -1;
+ errno = 0;
+ int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+ if (result == 0)
+ ec = (state & user_set_non_blocking)
+ ? asio::error::would_block : asio::error_code();
+ else if (result > 0)
+ ec = asio::error_code();
+ return result;
+}
+
+} // namespace descriptor_ops
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS)
+ // && !defined(ASIO_WINDOWS_RUNTIME)
+ // && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP