glib/gio/gunixinputstream.c

/* 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 <poll.h>

#include <glib.h>
#include <glib/gstdio.h>
#include "gioerror.h"
#include "gsimpleasyncresult.h"
#include "gunixinputstream.h"
#include "gcancellable.h"
#include "gasynchelper.h"
#include "glibintl.h"

#include "gioalias.h"

/**
 * SECTION:gunixinputstream
 * @short_description: Streaming input operations for Unix file descriptors
 * @include: gio/gunixinputstream.h
 * @see_also: #GInputStream
 *
 * #GUnixInputStream implements #GInputStream for reading from a
 * unix file descriptor, including asynchronous operations. The file
 * descriptor must be selectable, so it doesn't work with opened files.
 **/

G_DEFINE_TYPE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM);

struct _GUnixInputStreamPrivate {
  int fd;
  gboolean close_fd_at_close;
};

static gssize   g_unix_input_stream_read         (GInputStream         *stream,
						  void                 *buffer,
						  gsize                 count,
						  GCancellable         *cancellable,
						  GError              **error);
static gboolean g_unix_input_stream_close        (GInputStream         *stream,
						  GCancellable         *cancellable,
						  GError              **error);
static void     g_unix_input_stream_read_async   (GInputStream         *stream,
						  void                 *buffer,
						  gsize                 count,
						  int                   io_priority,
						  GCancellable         *cancellable,
						  GAsyncReadyCallback   callback,
						  gpointer              data);
static gssize   g_unix_input_stream_read_finish  (GInputStream         *stream,
						  GAsyncResult         *result,
						  GError              **error);
static void     g_unix_input_stream_skip_async   (GInputStream         *stream,
						  gsize                 count,
						  int                   io_priority,
						  GCancellable         *cancellable,
						  GAsyncReadyCallback   callback,
						  gpointer              data);
static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,
						  GAsyncResult         *result,
						  GError              **error);
static void     g_unix_input_stream_close_async  (GInputStream         *stream,
						  int                   io_priority,
						  GCancellable         *cancellable,
						  GAsyncReadyCallback   callback,
						  gpointer              data);
static gboolean g_unix_input_stream_close_finish (GInputStream         *stream,
						  GAsyncResult         *result,
						  GError              **error);


static void
g_unix_input_stream_finalize (GObject *object)
{
  GUnixInputStream *stream;
  
  stream = G_UNIX_INPUT_STREAM (object);

  if (G_OBJECT_CLASS (g_unix_input_stream_parent_class)->finalize)
    (*G_OBJECT_CLASS (g_unix_input_stream_parent_class)->finalize) (object);
}

static void
g_unix_input_stream_class_init (GUnixInputStreamClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
  
  g_type_class_add_private (klass, sizeof (GUnixInputStreamPrivate));
  
  gobject_class->finalize = g_unix_input_stream_finalize;

  stream_class->read_fn = g_unix_input_stream_read;
  stream_class->close_fn = g_unix_input_stream_close;
  stream_class->read_async = g_unix_input_stream_read_async;
  stream_class->read_finish = g_unix_input_stream_read_finish;
  if (0)
    {
      /* TODO: Implement instead of using fallbacks */
      stream_class->skip_async = g_unix_input_stream_skip_async;
      stream_class->skip_finish = g_unix_input_stream_skip_finish;
    }
  stream_class->close_async = g_unix_input_stream_close_async;
  stream_class->close_finish = g_unix_input_stream_close_finish;
}

static void
g_unix_input_stream_init (GUnixInputStream *unix_stream)
{
  unix_stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (unix_stream,
						   G_TYPE_UNIX_INPUT_STREAM,
						   GUnixInputStreamPrivate);
}

/**
 * g_unix_input_stream_new:
 * @fd: unix file descriptor.
 * @close_fd_at_close: a #gboolean.
 * 
 * Creates a new #GUnixInputStream for the given @fd. If @close_fd_at_close
 * is %TRUE, the file descriptor will be closed when the stream is closed.
 * 
 * Returns: a #GUnixInputStream. 
 **/
GInputStream *
g_unix_input_stream_new (int      fd,
			 gboolean close_fd_at_close)
{
  GUnixInputStream *stream;

  g_return_val_if_fail (fd != -1, NULL);

  stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM, NULL);

  stream->priv->fd = fd;
  stream->priv->close_fd_at_close = close_fd_at_close;
  
  return G_INPUT_STREAM (stream);
}

static gssize
g_unix_input_stream_read (GInputStream  *stream,
			  void          *buffer,
			  gsize          count,
			  GCancellable  *cancellable,
			  GError       **error)
{
  GUnixInputStream *unix_stream;
  gssize res;
  struct pollfd poll_fds[2];
  int poll_ret;
  int cancel_fd;

  unix_stream = G_UNIX_INPUT_STREAM (stream);

  cancel_fd = g_cancellable_get_fd (cancellable);
  if (cancel_fd != -1)
    {
      do
	{
	  poll_fds[0].events = POLLIN;
	  poll_fds[0].fd = unix_stream->priv->fd;
	  poll_fds[1].events = POLLIN;
	  poll_fds[1].fd = cancel_fd;
	  poll_ret = poll (poll_fds, 2, -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 reading from unix: %s"),
		       g_strerror (errsv));
	  return -1;
	}
    }

  while (1)
    {
      if (g_cancellable_set_error_if_cancelled (cancellable, error))
	break;
      res = read (unix_stream->priv->fd, buffer, count);
      if (res == -1)
	{
          int errsv = errno;

	  if (errsv == EINTR)
	    continue;
	  
	  g_set_error (error, G_IO_ERROR,
		       g_io_error_from_errno (errsv),
		       _("Error reading from unix: %s"),
		       g_strerror (errsv));
	}
      
      break;
    }

  return res;
}

static gboolean
g_unix_input_stream_close (GInputStream  *stream,
			   GCancellable  *cancellable,
			   GError       **error)
{
  GUnixInputStream *unix_stream;
  int res;

  unix_stream = G_UNIX_INPUT_STREAM (stream);

  if (!unix_stream->priv->close_fd_at_close)
    return TRUE;
  
  while (1)
    {
      /* 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 unix: %s"),
                       g_strerror (errsv));
        }
      break;
    }
  
  return res != -1;
}

typedef struct {
  gsize count;
  void *buffer;
  GAsyncReadyCallback callback;
  gpointer user_data;
  GCancellable *cancellable;
  GUnixInputStream *stream;
} ReadAsyncData;

static gboolean
read_async_cb (ReadAsyncData *data,
               GIOCondition   condition,
               int            fd)
{
  GSimpleAsyncResult *simple;
  GError *error = NULL;
  gssize count_read;

  /* We know that we can read from fd once without blocking */
  while (1)
    {
      if (g_cancellable_set_error_if_cancelled (data->cancellable, &error))
	{
	  count_read = -1;
	  break;
	}
      count_read = read (data->stream->priv->fd, data->buffer, data->count);
      if (count_read == -1)
	{
          int errsv = errno;

	  if (errsv == EINTR)
	    continue;
	  
	  g_set_error (&error, G_IO_ERROR,
		       g_io_error_from_errno (errsv),
		       _("Error reading from unix: %s"),
		       g_strerror (errsv));
	}
      break;
    }

  simple = g_simple_async_result_new (G_OBJECT (data->stream),
				      data->callback,
				      data->user_data,
				      g_unix_input_stream_read_async);

  g_simple_async_result_set_op_res_gssize (simple, count_read);

  if (count_read == -1)
    {
      g_simple_async_result_set_from_error (simple, error);
      g_error_free (error);
    }

  /* Complete immediately, not in idle, since we're already in a mainloop callout */
  g_simple_async_result_complete (simple);
  g_object_unref (simple);

  return FALSE;
}

static void
g_unix_input_stream_read_async (GInputStream        *stream,
				void                *buffer,
				gsize                count,
				int                  io_priority,
				GCancellable        *cancellable,
				GAsyncReadyCallback  callback,
				gpointer             user_data)
{
  GSource *source;
  GUnixInputStream *unix_stream;
  ReadAsyncData *data;

  unix_stream = G_UNIX_INPUT_STREAM (stream);

  data = g_new0 (ReadAsyncData, 1);
  data->count = count;
  data->buffer = buffer;
  data->callback = callback;
  data->user_data = user_data;
  data->cancellable = cancellable;
  data->stream = unix_stream;

  source = _g_fd_source_new (unix_stream->priv->fd,
			     POLLIN,
			     cancellable);
  
  g_source_set_callback (source, (GSourceFunc)read_async_cb, data, g_free);
  g_source_attach (source, NULL);
 
  g_source_unref (source);
}

static gssize
g_unix_input_stream_read_finish (GInputStream  *stream,
				 GAsyncResult  *result,
				 GError       **error)
{
  GSimpleAsyncResult *simple;
  gssize nread;

  simple = G_SIMPLE_ASYNC_RESULT (result);
  g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == g_unix_input_stream_read_async);
  
  nread = g_simple_async_result_get_op_res_gssize (simple);
  return nread;
}

static void
g_unix_input_stream_skip_async (GInputStream        *stream,
				gsize                count,
				int                  io_priority,
				GCancellable        *cancellable,
				GAsyncReadyCallback  callback,
				gpointer             data)
{
  g_warn_if_reached ();
  /* TODO: Not implemented */
}

static gssize
g_unix_input_stream_skip_finish  (GInputStream  *stream,
				  GAsyncResult  *result,
				  GError       **error)
{
  g_warn_if_reached ();
  return 0;
  /* TODO: Not implemented */
}


typedef struct {
  GInputStream *stream;
  GAsyncReadyCallback callback;
  gpointer user_data;
} CloseAsyncData;

static void
close_async_data_free (gpointer _data)
{
  CloseAsyncData *data = _data;

  g_free (data);
}

static gboolean
close_async_cb (CloseAsyncData *data)
{
  GUnixInputStream *unix_stream;
  GSimpleAsyncResult *simple;
  GError *error = NULL;
  gboolean result;
  int res;

  unix_stream = G_UNIX_INPUT_STREAM (data->stream);

  if (!unix_stream->priv->close_fd_at_close)
    {
      result = TRUE;
      goto out;
    }
  
  while (1)
    {
      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 unix: %s"),
                       g_strerror (errsv));
        }
      break;
    }
  
  result = res != -1;

 out:
  simple = g_simple_async_result_new (G_OBJECT (data->stream),
				      data->callback,
				      data->user_data,
				      g_unix_input_stream_close_async);

  if (!result)
    {
      g_simple_async_result_set_from_error (simple, error);
      g_error_free (error);
    }

  /* Complete immediately, not in idle, since we're already in a mainloop callout */
  g_simple_async_result_complete (simple);
  g_object_unref (simple);
  
  return FALSE;
}

static void
g_unix_input_stream_close_async (GInputStream        *stream,
				 int                  io_priority,
				 GCancellable        *cancellable,
				 GAsyncReadyCallback  callback,
				 gpointer             user_data)
{
  GSource *idle;
  CloseAsyncData *data;

  data = g_new0 (CloseAsyncData, 1);

  data->stream = stream;
  data->callback = callback;
  data->user_data = user_data;
  
  idle = g_idle_source_new ();
  g_source_set_callback (idle, (GSourceFunc)close_async_cb, data, close_async_data_free);
  g_source_attach (idle, NULL);
  g_source_unref (idle);
}

static gboolean
g_unix_input_stream_close_finish (GInputStream  *stream,
				  GAsyncResult  *result,
				  GError       **error)
{
  /* Failures handled in generic close_finish code */
  return TRUE;
}

#define __G_UNIX_INPUT_STREAM_C__
#include "gioaliasdef.c"