text: /* GIO - GLib Input, Output and Streaming Library
   * 
   * Copyright (C) 2006-2007 Red Hat, Inc.
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General
   * Public License along with this library; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
   * Boston, MA 02111-1307, USA.
   *
   * Author: Alexander Larsson <alexl@redhat.com>
   */
  
  #include "config.h"
  
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <unistd.h>
  #include <errno.h>
  #include <stdio.h>
  #include <fcntl.h>
  
  #include <glib.h>
  #include <glib/gstdio.h>
  #include <glib/glib-unix.h>
  #include "gioerror.h"
  #include "gunixoutputstream.h"
  #include "gcancellable.h"
  #include "gsimpleasyncresult.h"
  #include "gasynchelper.h"
  #include "gfiledescriptorbased.h"
  #include "glibintl.h"
  
  
  /**
   * SECTION:gunixoutputstream
   * @short_description: Streaming output operations for UNIX file descriptors
   * @include: gio/gunixoutputstream.h
   * @see_also: #GOutputStream
   *
   * #GUnixOutputStream implements #GOutputStream for writing to a UNIX
   * file descriptor, including asynchronous operations. (If the file
   * descriptor refers to a socket or pipe, this will use poll() to do
   * asynchronous I/O. If it refers to a regular file, it will fall back
   * to doing asynchronous I/O in another thread.)
   *
   * Note that <filename>&lt;gio/gunixoutputstream.h&gt;</filename> belongs
   * to the UNIX-specific GIO interfaces, thus you have to use the
   * <filename>gio-unix-2.0.pc</filename> pkg-config file when using it.
   */
  
  enum {
    PROP_0,
    PROP_FD,
    PROP_CLOSE_FD
  };
  
  struct _GUnixOutputStreamPrivate {
    int fd;
    guint close_fd : 1;
    guint is_pipe_or_socket : 1;
  };
  
  static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
  static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);
  
  G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
                           G_ADD_PRIVATE (GUnixOutputStream)
  			 G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
  						g_unix_output_stream_pollable_iface_init)
  			 G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
  						g_unix_output_stream_file_descriptor_based_iface_init)
  			 )
  
  static void     g_unix_output_stream_set_property (GObject              *object,
  						   guint                 prop_id,
  						   const GValue         *value,
  						   GParamSpec           *pspec);
  static void     g_unix_output_stream_get_property (GObject              *object,
  						   guint                 prop_id,
  						   GValue               *value,
  						   GParamSpec           *pspec);
  static gssize   g_unix_output_stream_write        (GOutputStream        *stream,
  						   const void           *buffer,
  						   gsize                 count,
  						   GCancellable         *cancellable,
  						   GError              **error);
  static gboolean g_unix_output_stream_close        (GOutputStream        *stream,
  						   GCancellable         *cancellable,
  						   GError              **error);
  static void     g_unix_output_stream_close_async  (GOutputStream        *stream,
  						   int                   io_priority,
  						   GCancellable         *cancellable,
  						   GAsyncReadyCallback   callback,
  						   gpointer              data);
  static gboolean g_unix_output_stream_close_finish (GOutputStream        *stream,
  						   GAsyncResult         *result,
  						   GError              **error);
  
  static gboolean g_unix_output_stream_pollable_can_poll      (GPollableOutputStream *stream);
  static gboolean g_unix_output_stream_pollable_is_writable   (GPollableOutputStream *stream);
  static GSource *g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
  							     GCancellable         *cancellable);
  
  static void
  g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
  {
    GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
    GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);
  
    gobject_class->get_property = g_unix_output_stream_get_property;
    gobject_class->set_property = g_unix_output_stream_set_property;
  
    stream_class->write_fn = g_unix_output_stream_write;
    stream_class->close_fn = g_unix_output_stream_close;
    stream_class->close_async = g_unix_output_stream_close_async;
    stream_class->close_finish = g_unix_output_stream_close_finish;
  
     /**
     * GUnixOutputStream:fd:
     *
     * The file descriptor that the stream writes to.
     *
     * Since: 2.20
     */
    g_object_class_install_property (gobject_class,
  				   PROP_FD,
  				   g_param_spec_int ("fd",
  						     P_("File descriptor"),
  						     P_("The file descriptor to write to"),
  						     G_MININT, G_MAXINT, -1,
  						     G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
  
    /**
     * GUnixOutputStream:close-fd:
     *
     * Whether to close the file descriptor when the stream is closed.
     *
     * Since: 2.20
     */
    g_object_class_install_property (gobject_class,
  				   PROP_CLOSE_FD,
  				   g_param_spec_boolean ("close-fd",
  							 P_("Close file descriptor"),
  							 P_("Whether to close the file descriptor when the stream is closed"),
  							 TRUE,
  							 G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
  }
  
  static void
  g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
  {
    iface->can_poll = g_unix_output_stream_pollable_can_poll;
    iface->is_writable = g_unix_output_stream_pollable_is_writable;
    iface->create_source = g_unix_output_stream_pollable_create_source;
  }
  
  static void
  g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
  {
    iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
  }
  
  static void
  g_unix_output_stream_set_property (GObject         *object,
  				   guint            prop_id,
  				   const GValue    *value,
  				   GParamSpec      *pspec)
  {
    GUnixOutputStream *unix_stream;
  
    unix_stream = G_UNIX_OUTPUT_STREAM (object);
  
    switch (prop_id)
      {
      case PROP_FD:
        unix_stream->priv->fd = g_value_get_int (value);
        if (lseek (unix_stream->priv->fd, 0, SEEK_CUR) == -1 && errno == ESPIPE)
  	unix_stream->priv->is_pipe_or_socket = TRUE;
        else
  	unix_stream->priv->is_pipe_or_socket = FALSE;
        break;
      case PROP_CLOSE_FD:
        unix_stream->priv->close_fd = g_value_get_boolean (value);
        break;
      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
      }
  }
  
  static void
  g_unix_output_stream_get_property (GObject    *object,
  				   guint       prop_id,
  				   GValue     *value,
  				   GParamSpec *pspec)
  {
    GUnixOutputStream *unix_stream;
  
    unix_stream = G_UNIX_OUTPUT_STREAM (object);
  
    switch (prop_id)
      {
      case PROP_FD:
        g_value_set_int (value, unix_stream->priv->fd);
        break;
      case PROP_CLOSE_FD:
        g_value_set_boolean (value, unix_stream->priv->close_fd);
        break;
      default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      }
  }
  
  static void
  g_unix_output_stream_init (GUnixOutputStream *unix_stream)
  {
    unix_stream->priv = g_unix_output_stream_get_instance_private (unix_stream);
    unix_stream->priv->fd = -1;
    unix_stream->priv->close_fd = TRUE;
  }
  
  /**
   * g_unix_output_stream_new:
   * @fd: a UNIX file descriptor
   * @close_fd: %TRUE to close the file descriptor when done
   * 
   * Creates a new #GUnixOutputStream for the given @fd. 
   * 
   * If @close_fd, is %TRUE, the file descriptor will be closed when 
   * the output stream is destroyed.
   * 
   * Returns: a new #GOutputStream
   **/
  GOutputStream *
  g_unix_output_stream_new (gint     fd,
  			  gboolean close_fd)
  {
    GUnixOutputStream *stream;
  
    g_return_val_if_fail (fd != -1, NULL);
  
    stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
  			 "fd", fd,
  			 "close-fd", close_fd,
  			 NULL);
    
    return G_OUTPUT_STREAM (stream);
  }
  
  /**
   * g_unix_output_stream_set_close_fd:
   * @stream: a #GUnixOutputStream
   * @close_fd: %TRUE to close the file descriptor when done
   *
   * Sets whether the file descriptor of @stream shall be closed
   * when the stream is closed.
   *
   * Since: 2.20
   */
  void
  g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
                                     gboolean           close_fd)
  {
    g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));
  
    close_fd = close_fd != FALSE;
    if (stream->priv->close_fd != close_fd)
      {
        stream->priv->close_fd = close_fd;
        g_object_notify (G_OBJECT (stream), "close-fd");
      }
  }
  
  /**
   * g_unix_output_stream_get_close_fd:
   * @stream: a #GUnixOutputStream
   *
   * Returns whether the file descriptor of @stream will be
   * closed when the stream is closed.
   *
   * Return value: %TRUE if the file descriptor is closed when done
   *
   * Since: 2.20
   */
  gboolean
  g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
  {
    g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);
  
    return stream->priv->close_fd;
  }
  
  /**
   * g_unix_output_stream_get_fd:
   * @stream: a #GUnixOutputStream
   *
   * Return the UNIX file descriptor that the stream writes to.
   *
   * Return value: The file descriptor of @stream
   *
   * Since: 2.20
   */
  gint
  g_unix_output_stream_get_fd (GUnixOutputStream *stream)
  {
    g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);
  
    return stream->priv->fd;
  }
  
  static gssize
  g_unix_output_stream_write (GOutputStream  *stream,
  			    const void     *buffer,
  			    gsize           count,
  			    GCancellable   *cancellable,
  			    GError        **error)
  {
    GUnixOutputStream *unix_stream;
    gssize res = -1;
    GPollFD poll_fds[2];
    int nfds;
    int poll_ret;
  
    unix_stream = G_UNIX_OUTPUT_STREAM (stream);
  
    poll_fds[0].fd = unix_stream->priv->fd;
    poll_fds[0].events = G_IO_OUT;
  
    if (unix_stream->priv->is_pipe_or_socket &&
        g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
      nfds = 2;
    else
      nfds = 1;
  
    while (1)
      {
        poll_fds[0].revents = poll_fds[1].revents = 0;
        do
  	poll_ret = g_poll (poll_fds, nfds, -1);
        while (poll_ret == -1 && errno == EINTR);
  
        if (poll_ret == -1)
  	{
            int errsv = errno;
  
  	  g_set_error (error, G_IO_ERROR,
  		       g_io_error_from_errno (errsv),
  		       _("Error writing to file descriptor: %s"),
  		       g_strerror (errsv));
  	  break;
  	}
  
        if (g_cancellable_set_error_if_cancelled (cancellable, error))
  	break;
  
        if (!poll_fds[0].revents)
  	continue;
  
        res = write (unix_stream->priv->fd, buffer, count);
        if (res == -1)
  	{
            int errsv = errno;
  
  	  if (errsv == EINTR || errsv == EAGAIN)
  	    continue;
  
  	  g_set_error (error, G_IO_ERROR,
  		       g_io_error_from_errno (errsv),
  		       _("Error writing to file descriptor: %s"),
  		       g_strerror (errsv));
  	}
  
        break;
      }
  
    if (nfds == 2)
      g_cancellable_release_fd (cancellable);
    return res;
  }
  
  static gboolean
  g_unix_output_stream_close (GOutputStream  *stream,
  			    GCancellable   *cancellable,
  			    GError        **error)
  {
    GUnixOutputStream *unix_stream;
    int res;
  
    unix_stream = G_UNIX_OUTPUT_STREAM (stream);
  
    if (!unix_stream->priv->close_fd)
      return TRUE;
    
    /* This might block during the close. Doesn't seem to be a way to avoid it though. */
    res = close (unix_stream->priv->fd);
    if (res == -1)
      {
        int errsv = errno;
  
        g_set_error (error, G_IO_ERROR,
  		   g_io_error_from_errno (errsv),
  		   _("Error closing file descriptor: %s"),
  		   g_strerror (errsv));
      }
  
    return res != -1;
  }
  
  static void
  g_unix_output_stream_close_async (GOutputStream       *stream,
  				  int                  io_priority,
  				  GCancellable        *cancellable,
  				  GAsyncReadyCallback  callback,
  				  gpointer             user_data)
  {
    GTask *task;
    GError *error = NULL;
  
    task = g_task_new (stream, cancellable, callback, user_data);
    g_task_set_priority (task, io_priority);
  
    if (g_unix_output_stream_close (stream, cancellable, &error))
      g_task_return_boolean (task, TRUE);
    else
      g_task_return_error (task, error);
    g_object_unref (task);
  }
  
  static gboolean
  g_unix_output_stream_close_finish (GOutputStream  *stream,
  				   GAsyncResult   *result,
  				   GError        **error)
  {
    g_return_val_if_fail (g_task_is_valid (result, stream), FALSE);
  
    return g_task_propagate_boolean (G_TASK (result), error);
  }
  
  static gboolean
  g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream)
  {
    return G_UNIX_OUTPUT_STREAM (stream)->priv->is_pipe_or_socket;
  }
  
  static gboolean
  g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
  {
    GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
    GPollFD poll_fd;
    gint result;
  
    poll_fd.fd = unix_stream->priv->fd;
    poll_fd.events = G_IO_OUT;
    poll_fd.revents = 0;
  
    do
      result = g_poll (&poll_fd, 1, 0);
    while (result == -1 && errno == EINTR);
  
    return poll_fd.revents != 0;
  }
  
  static GSource *
  g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
  					     GCancellable          *cancellable)
  {
    GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
    GSource *inner_source, *cancellable_source, *pollable_source;
  
    pollable_source = g_pollable_source_new (G_OBJECT (stream));
  
    inner_source = g_unix_fd_source_new (unix_stream->priv->fd, G_IO_OUT);
    g_source_set_dummy_callback (inner_source);
    g_source_add_child_source (pollable_source, inner_source);
    g_source_unref (inner_source);
  
    if (cancellable)
      {
        cancellable_source = g_cancellable_source_new (cancellable);
        g_source_set_dummy_callback (cancellable_source);
        g_source_add_child_source (pollable_source, cancellable_source);
        g_source_unref (cancellable_source);
      }
  
    return pollable_source;
  }
  