giochannel.c 65.8 KB
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/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * giochannel.c: IO Channel abstraction
 * Copyright 1998 Owen Taylor
 *
 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * 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
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

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/*
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 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
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 * file for a list of people on the GLib Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GLib at ftp://ftp.gtk.org/pub/gtk/. 
 */

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/* 
 * MT safe
 */

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#include "config.h"
#include "giochannel.h"

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#include <string.h>
#include <errno.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#undef G_DISABLE_DEPRECATED

#include "glib.h"

#include "glibintl.h"

#define G_IO_NICE_BUF_SIZE	1024

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/* This needs to be as wide as the largest character in any possible encoding */
#define MAX_CHAR_SIZE		10

/* Some simplifying macros, which reduce the need to worry whether the
 * buffers have been allocated. These also make USE_BUF () an lvalue,
 * which is used in g_io_channel_read_to_end ().
 */
#define USE_BUF(channel)	((channel)->encoding ? (channel)->encoded_read_buf \
				 : (channel)->read_buf)
#define BUF_LEN(string)		((string) ? (string)->len : 0)

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static GIOError		g_io_error_get_from_g_error	(GIOStatus    status,
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							 GError      *err);
static void		g_io_channel_purge		(GIOChannel  *channel);
static GIOStatus	g_io_channel_fill_buffer	(GIOChannel  *channel,
							 GError     **err);
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static GIOStatus	g_io_channel_read_line_backend	(GIOChannel  *channel,
							 gsize       *length,
							 gsize       *terminator_pos,
							 GError     **error);
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void
g_io_channel_init (GIOChannel *channel)
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{
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  channel->ref_count = 1;
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  channel->encoding = g_strdup ("UTF-8");
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  channel->line_term = NULL;
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  channel->line_term_len = 0;
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  channel->buf_size = G_IO_NICE_BUF_SIZE;
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  channel->read_cd = (GIConv) -1;
  channel->write_cd = (GIConv) -1;
  channel->read_buf = NULL; /* Lazy allocate buffers */
  channel->encoded_read_buf = NULL;
  channel->write_buf = NULL;
  channel->partial_write_buf[0] = '\0';
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  channel->use_buffer = TRUE;
  channel->do_encode = FALSE;
  channel->close_on_unref = FALSE;
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}

void 
g_io_channel_ref (GIOChannel *channel)
{
  g_return_if_fail (channel != NULL);

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  channel->ref_count++;
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}

void 
g_io_channel_unref (GIOChannel *channel)
{
  g_return_if_fail (channel != NULL);

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  channel->ref_count--;
  if (channel->ref_count == 0)
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    {
      if (channel->close_on_unref)
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        g_io_channel_shutdown (channel, TRUE, NULL);
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      else
        g_io_channel_purge (channel);
      g_free (channel->encoding);
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      if (channel->read_cd != (GIConv) -1)
        g_iconv_close (channel->read_cd);
      if (channel->write_cd != (GIConv) -1)
        g_iconv_close (channel->write_cd);
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      if (channel->line_term)
        g_free (channel->line_term);
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      if (channel->read_buf)
        g_string_free (channel->read_buf, TRUE);
      if (channel->write_buf)
        g_string_free (channel->write_buf, TRUE);
      if (channel->encoded_read_buf)
        g_string_free (channel->encoded_read_buf, TRUE);
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      channel->funcs->io_free (channel);
    }
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}

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static GIOError
g_io_error_get_from_g_error (GIOStatus status,
			     GError *err)
{
  switch (status)
    {
      case G_IO_STATUS_NORMAL:
      case G_IO_STATUS_EOF:
        return G_IO_ERROR_NONE;
      case G_IO_STATUS_AGAIN:
        return G_IO_ERROR_AGAIN;
      case G_IO_STATUS_ERROR:
        if (err->domain != G_IO_CHANNEL_ERROR)
          return G_IO_ERROR_UNKNOWN;
        switch (err->code)
          {
            case G_IO_CHANNEL_ERROR_INVAL:
              return G_IO_ERROR_INVAL;
            default:
              return G_IO_ERROR_UNKNOWN;
          }
      default:
        g_assert_not_reached ();
        return G_IO_ERROR_UNKNOWN; /* Keep the compiler happy */
    }
}

/**
 * g_io_channel_read:
 * @channel: a #GIOChannel. 
 * @buf: a buffer to read the data into (which should be at least count bytes long).
 * @count: the number of bytes to read from the #GIOChannel.
 * @bytes_read: returns the number of bytes actually read. 
 * 
 * Reads data from a #GIOChannel. This function is depricated. New code should
 * use g_io_channel_read_chars() instead.
 * 
 * Return value: %G_IO_ERROR_NONE if the operation was successful. 
 **/
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GIOError 
g_io_channel_read (GIOChannel *channel, 
		   gchar      *buf, 
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		   gsize       count,
		   gsize      *bytes_read)
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{
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  GError *err = NULL;
  GIOError error;
  GIOStatus status;

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  g_return_val_if_fail (channel != NULL, G_IO_ERROR_UNKNOWN);
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  g_return_val_if_fail (bytes_read != NULL, G_IO_ERROR_UNKNOWN);

  status = channel->funcs->io_read (channel, buf, count, bytes_read, &err);
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  error = g_io_error_get_from_g_error (status, err);

  if (err)
    g_error_free (err);

  return error;
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}

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/**
 * g_io_channel_write:
 * @channel:  a #GIOChannel.
 * @buf: the buffer containing the data to write. 
 * @count: the number of bytes to write.
 * @bytes_written:  the number of bytes actually written.
 * 
 * Writes data to a #GIOChannel. This function is depricated. New code should
 * use g_io_channel_write_chars() instead.
 * 
 * Return value:  %G_IO_ERROR_NONE if the operation was successful.
 **/
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GIOError 
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g_io_channel_write (GIOChannel  *channel, 
		    const gchar *buf, 
		    gsize        count,
		    gsize       *bytes_written)
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{
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  GError *err = NULL;
  GIOError error;
  GIOStatus status;

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  g_return_val_if_fail (channel != NULL, G_IO_ERROR_UNKNOWN);
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  g_return_val_if_fail (bytes_written != NULL, G_IO_ERROR_UNKNOWN);

  status = channel->funcs->io_write (channel, buf, count, bytes_written, &err);

  error = g_io_error_get_from_g_error (status, err);
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  if (err)
    g_error_free (err);

  return error;
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}

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/**
 * g_io_channel_seek:
 * @channel: a #GIOChannel. 
 * @offset: an offset, in bytes, which is added to the position specified by @type
 * @type: the position in the file, which can be %G_SEEK_CUR (the current
 *        position), %G_SEEK_SET (the start of the file), or %G_SEEK_END (the end of the
 *        file).
 * 
 * Sets the current position in the #GIOChannel, similar to the standard library
 * function fseek(). This function is depricated. New code should
 * use g_io_channel_seek_position() instead.
 * 
 * Return value: %G_IO_ERROR_NONE if the operation was successful.
 **/
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GIOError 
g_io_channel_seek  (GIOChannel   *channel,
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		    glong         offset, 
		    GSeekType     type)
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{
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  GError *err = NULL;
  GIOError error;
  GIOStatus status;

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  g_return_val_if_fail (channel != NULL, G_IO_ERROR_UNKNOWN);
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  g_return_val_if_fail (channel->is_seekable, G_IO_ERROR_UNKNOWN);
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  switch (type)
    {
      case G_SEEK_CUR:
      case G_SEEK_SET:
      case G_SEEK_END:
        break;
      default:
        g_warning ("g_io_channel_seek: unknown seek type");
        return G_IO_ERROR_UNKNOWN;
    }

  status = channel->funcs->io_seek (channel, offset, type, &err);

  error = g_io_error_get_from_g_error (status, err);

  if (err)
    g_error_free (err);

  return error;
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}
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/* The function g_io_channel_new_file() is prototyped in both
 * giounix.c and giowin32.c, so we stick its documentation here.
 */

/**
 * g_io_channel_new_file:
 * @filename: A string containing the name of a file.
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 * @mode: One of "r", "w", "a", "r+", "w+", "a+". These have
 *        the same meaning as in fopen().
 * @error: A location to return an error of type %G_IO_FILE_ERROR.
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 *
 * Open a file @filename as a #GIOChannel using mode @mode. This
 * channel will be closed when the last reference to it is dropped,
 * so there is no need to call g_io_channel_close() (though doing
 * so will not cause problems, as long as no attempt is made to
 * access the channel after it is closed).
 *
 * Return value: A #GIOChannel on success, %NULL on failure.
 **/

/**
 * g_io_channel_close:
 * @channel: A #GIOChannel
 * 
 * Close an IO channel. Any pending data to be written will be
 * flushed, ignoring errors. The channel will not be freed until the
 * last reference is dropped using g_io_channel_unref(). This
 * function is deprecated: you should use g_io_channel_shutdown()
 * instead.
 **/
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void
g_io_channel_close (GIOChannel *channel)
{
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  GError *err = NULL;
  
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  g_return_if_fail (channel != NULL);

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  g_io_channel_purge (channel);

  channel->funcs->io_close (channel, &err);

  if (err)
    { /* No way to return the error */
      g_warning ("Error closing channel: %s", err->message);
      g_error_free (err);
    }
  
  channel->close_on_unref = FALSE; /* Because we already did */
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  channel->is_readable = FALSE;
  channel->is_writeable = FALSE;
  channel->is_seekable = FALSE;
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}

/**
 * g_io_channel_shutdown:
 * @channel: a #GIOChannel
 * @flush: if %TRUE, flush pending
 * @err: location to store a #GIOChannelError
 * 
 * Close an IO channel. Any pending data to be written will be
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 * flushed if @flush is %TRUE. The channel will not be freed until the
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 * last reference is dropped using g_io_channel_unref().
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 *
 * Return value:
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 **/
GIOStatus
g_io_channel_shutdown (GIOChannel *channel,
		       gboolean    flush,
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		       GError    **err)
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{
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  GIOStatus status, result;
  GError *tmperr = NULL;
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  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);
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  g_return_val_if_fail (err == NULL || *err == NULL, G_IO_STATUS_ERROR);
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  if (flush && channel->write_buf && channel->write_buf->len > 0)
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    {
      GIOFlags flags;
      
      /* Set the channel to blocking, to avoid a busy loop
       */
      flags = g_io_channel_get_flags (channel);
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      /* Ignore any errors here, they're irrelevant */
      g_io_channel_set_flags (channel, flags & ~G_IO_FLAG_NONBLOCK, NULL);

      result = g_io_channel_flush (channel, &tmperr);

      if (channel->partial_write_buf[0] != '\0')
        {
          g_warning ("Partial character at end of write buffer not flushed.\n");
          channel->partial_write_buf[0] = '\0';
        }
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    }
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  else
    result = G_IO_STATUS_NORMAL;
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  status = channel->funcs->io_close (channel, err);
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  channel->close_on_unref = FALSE; /* Because we already did */
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  channel->is_readable = FALSE;
  channel->is_writeable = FALSE;
  channel->is_seekable = FALSE;
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  if (status != G_IO_STATUS_NORMAL)
    {
      g_clear_error (&tmperr);
      return status;
    }
  else if (result != G_IO_STATUS_NORMAL)
    {
      g_propagate_error (err, tmperr);
      return result;
    }
  else
    return G_IO_STATUS_NORMAL;
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}

/* This function is used for the final flush on close or unref */
static void
g_io_channel_purge (GIOChannel *channel)
{
  GError *err = NULL;
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  GIOStatus status;
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  g_return_if_fail (channel != NULL);

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  if (channel->write_buf && channel->write_buf->len > 0)
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    {
      GIOFlags flags;
      
      /* Set the channel to blocking, to avoid a busy loop
       */
      flags = g_io_channel_get_flags (channel);
      g_io_channel_set_flags (channel, flags & ~G_IO_FLAG_NONBLOCK, NULL);

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      status = g_io_channel_flush (channel, &err);
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      if (err)
	{ /* No way to return the error */
	  g_warning ("Error flushing string: %s", err->message);
	  g_error_free (err);
	}
    }

  /* Flush these in case anyone tries to close without unrefing */

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  if (channel->read_buf)
    g_string_truncate (channel->read_buf, 0);
  if (channel->write_buf)
    g_string_truncate (channel->write_buf, 0);
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  if (channel->encoding)
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    {
      if (channel->encoded_read_buf)
        g_string_truncate (channel->encoded_read_buf, 0);

      if (channel->partial_write_buf[0] != '\0')
        {
          g_warning ("Partial character at end of write buffer not flushed.\n");
          channel->partial_write_buf[0] = '\0';
        }
    }
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}

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GSource *
g_io_create_watch (GIOChannel  *channel,
		   GIOCondition condition)
{
  g_return_val_if_fail (channel != NULL, NULL);

  return channel->funcs->io_create_watch (channel, condition);
}

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guint 
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g_io_add_watch_full (GIOChannel    *channel,
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		     gint           priority,
		     GIOCondition   condition,
		     GIOFunc        func,
		     gpointer       user_data,
		     GDestroyNotify notify)
{
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  GSource *source;
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  guint id;
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  g_return_val_if_fail (channel != NULL, 0);

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  source = g_io_create_watch (channel, condition);

  if (priority != G_PRIORITY_DEFAULT)
    g_source_set_priority (source, priority);
  g_source_set_callback (source, (GSourceFunc)func, user_data, notify);

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  id = g_source_attach (source, NULL);
  g_source_unref (source);

  return id;
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}

guint 
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g_io_add_watch (GIOChannel    *channel,
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		GIOCondition   condition,
		GIOFunc        func,
		gpointer       user_data)
{
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  return g_io_add_watch_full (channel, G_PRIORITY_DEFAULT, condition, func, user_data, NULL);
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}
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/**
 * g_io_channel_get_buffer_condition:
 * @channel: A #GIOChannel
 *
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 * This function returns a #GIOCondition depending on whether there
 * is data to be read/space to write data in the
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 * internal buffers in the #GIOChannel. Only the flags %G_IO_IN and
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 * %G_IO_OUT may be set.
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 *
 * Return value: A #GIOCondition
 **/
GIOCondition
g_io_channel_get_buffer_condition (GIOChannel *channel)
{
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  GIOCondition condition = 0;

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  if (channel->encoding)
    {
      if (channel->encoded_read_buf && (channel->encoded_read_buf->len > 0))
        condition |= G_IO_IN; /* Only return if we have full characters */
    }
  else
    {
      if (channel->read_buf && (channel->read_buf->len > 0))
        condition |= G_IO_IN;
    }
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  if (channel->write_buf && (channel->write_buf->len < channel->buf_size))
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    condition |= G_IO_OUT;
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  return condition;
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}

/**
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 * g_io_channel_error_from_errno:
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 * @en: An errno error number, e.g. EINVAL
 *
 * Return value: A #GIOChannelError error number, e.g. %G_IO_CHANNEL_ERROR_INVAL
 **/
GIOChannelError
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g_io_channel_error_from_errno (gint en)
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{
#ifdef EAGAIN
  g_return_val_if_fail (en != EAGAIN, G_IO_CHANNEL_ERROR_FAILED);
#endif
#ifdef EINTR
  g_return_val_if_fail (en != EINTR, G_IO_CHANNEL_ERROR_FAILED);
#endif

  switch (en)
    {
#ifdef EBADF
    case EBADF:
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      g_warning("Invalid file descriptor.\n");
      return G_IO_CHANNEL_ERROR_FAILED;
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#endif

#ifdef EFAULT
    case EFAULT:
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      g_warning("File descriptor outside valid address space.\n");
      return G_IO_CHANNEL_ERROR_FAILED;
#endif

#ifdef EFBIG
    case EFBIG:
      return G_IO_CHANNEL_ERROR_FBIG;
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#endif

#ifdef EINVAL
    case EINVAL:
      return G_IO_CHANNEL_ERROR_INVAL;
#endif

#ifdef EIO
    case EIO:
      return G_IO_CHANNEL_ERROR_IO;
#endif

#ifdef EISDIR
    case EISDIR:
      return G_IO_CHANNEL_ERROR_ISDIR;
#endif

#ifdef ENOSPC
    case ENOSPC:
      return G_IO_CHANNEL_ERROR_NOSPC;
#endif

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#ifdef ENXIO
    case ENXIO:
      return G_IO_CHANNEL_ERROR_NXIO;
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#endif
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#ifdef EOVERFLOW
    case EOVERFLOW:
      return G_IO_CHANNEL_ERROR_OVERFLOW;
#endif

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#ifdef EPIPE
    case EPIPE:
      return G_IO_CHANNEL_ERROR_PIPE;
#endif

    default:
      return G_IO_CHANNEL_ERROR_FAILED;
    }
}

/**
 * g_io_channel_set_buffer_size:
 * @channel: a #GIOChannel
 * @size: the size of the buffer. 0 == pick a good size
 *
 * Set the buffer size.
 **/  
void
g_io_channel_set_buffer_size (GIOChannel	*channel,
                              gsize		 size)
{
  g_return_if_fail (channel != NULL);

  if (size == 0)
    size = G_IO_NICE_BUF_SIZE;

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  if (size < MAX_CHAR_SIZE)
    size = MAX_CHAR_SIZE;
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  channel->buf_size = size;
}

/**
 * g_io_channel_get_buffer_size:
 * @channel: a #GIOChannel
 *
 * Get the buffer size.
 *
 * Return value: the size of the buffer.
 **/  
gsize
g_io_channel_get_buffer_size (GIOChannel	*channel)
{
  g_return_val_if_fail (channel != NULL, 0);

  return channel->buf_size;
}

/**
 * g_io_channel_set_line_term:
 * @channel: a #GIOChannel
 * @line_term: The line termination string. Use %NULL for auto detect.
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 *             Auto detection breaks on "\n", "\r\n", "\r", "\0", and
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 *             the unicode paragraph separator. Auto detection should
 *             not be used for anything other than file-based channels.
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 * @length: The length of the termination string. If -1 is passed, the
 *          string is assumed to be null terminated. This option allows
 *          termination strings with embeded nulls.
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 *
 * This sets the string that #GIOChannel uses to determine
 * where in the file a line break occurs.
 **/
void
g_io_channel_set_line_term (GIOChannel	*channel,
642
643
                            const gchar	*line_term,
			    gint         length)
644
645
{
  g_return_if_fail (channel != NULL);
646
  g_return_if_fail (line_term == NULL || length != 0); /* Disallow "" */
647

648
649
650
651
652
653
654
655
656
  if (line_term == NULL)
    length = 0;
  else if (length < 0)
    length = strlen (line_term);

  if (channel->line_term)
    g_free (channel->line_term);
  channel->line_term = line_term ? g_memdup (line_term, length) : NULL;
  channel->line_term_len = length;
657
658
659
660
661
}

/**
 * g_io_channel_get_line_term:
 * @channel: a #GIOChannel
662
 * @length: a location to return the length of the line terminator
663
664
665
666
667
668
669
670
671
 *
 * This returns the string that #GIOChannel uses to determine
 * where in the file a line break occurs. A value of %NULL
 * indicates auto detection.
 *
 * Return value: The line termination string. This value
 *   is owned by GLib and must not be freed.
 **/
G_CONST_RETURN gchar*
672
673
g_io_channel_get_line_term (GIOChannel	*channel,
			    gint        *length)
674
675
676
{
  g_return_val_if_fail (channel != NULL, 0);

677
678
679
  if (length)
    *length = channel->line_term_len;

680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
  return channel->line_term;
}

/**
 * g_io_channel_set_flags:
 * @channel: a #GIOChannel
 * @flags: the flags to set on the channel
 * @error: A location to return an error of type #GIOChannelError
 *
 * Return value:
 **/
GIOStatus
g_io_channel_set_flags (GIOChannel *channel,
                        GIOFlags    flags,
                        GError    **error)
{
  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail ((error == NULL) || (*error == NULL),
			G_IO_STATUS_ERROR);

  return (* channel->funcs->io_set_flags)(channel,
					  flags & G_IO_FLAG_SET_MASK,
					  error);
}

/**
 * g_io_channel_get_flags:
 * @channel: a #GIOChannel
 *
 * Gets the current flags for a #GIOChannel, including read-only
 * flags such as %G_IO_FLAG_IS_READABLE.
711
 *
712
713
714
715
716
717
718
 * The values of the flags %G_IO_FLAG_IS_READABLE and %G_IO_FLAG_IS_WRITEABLE
 * are cached for internal use by the channel when it is created.
 * If they should change at some later point (e.g. partial shutdown
 * of a socket with the unix shutdown () function), the user
 * should immediately call g_io_channel_get_flags () to update
 * the internal values of these flags.
 *
719
 * Return value: the flags which are set on the channel
720
721
722
723
 **/
GIOFlags
g_io_channel_get_flags (GIOChannel *channel)
{
724
725
  GIOFlags flags;

726
727
  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);

728
729
730
731
732
733
734
735
736
737
738
739
  flags = (* channel->funcs->io_get_flags) (channel);

  /* Cross implementation code */

  if (channel->is_seekable)
    flags |= G_IO_FLAG_IS_SEEKABLE;
  if (channel->is_readable)
    flags |= G_IO_FLAG_IS_READABLE;
  if (channel->is_writeable)
    flags |= G_IO_FLAG_IS_WRITEABLE;

  return flags;
740
741
}

742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
/**
 * g_io_channel_set_close_on_unref:
 * @channel: a #GIOChannel
 * @do_close: Whether to close the channel on the final unref of
 *            the GIOChannel data structure. The default value of
 *            this is %TRUE for channels created by g_io_channel_new_file (),
 *            and %FALSE for all other channels.
 *
 * Setting this flag to %TRUE for a channel you have already closed
 * can cause problems.
 **/
void
g_io_channel_set_close_on_unref	(GIOChannel *channel,
				 gboolean    do_close)
{
  g_return_if_fail (channel != NULL);

  channel->close_on_unref = do_close;
}

/**
 * g_io_channel_get_close_on_unref:
 * @channel: a #GIOChannel
 *
 * Return value: Whether the channel will be closedi on the final unref of
 *               the GIOChannel data structure. The default value of
 *               this is %TRUE for channels created by g_io_channel_new_file (),
 *               and %FALSE for all other channels.
 **/
gboolean
g_io_channel_get_close_on_unref	(GIOChannel *channel)
{
  g_return_val_if_fail (channel != NULL, FALSE);

  return channel->close_on_unref;
}

779
780
781
782
/**
 * g_io_channel_seek_position:
 * @channel: a #GIOChannel
 * @offset: The offset in bytes from the position specified by @type
783
784
785
786
 * @type: a #GSeekType. The type %G_SEEK_CUR is only allowed in those
 *                      cases where a call to g_io_channel_set_encoding ()
 *                      is allowed. See the documentation for
 *                      g_io_channel_set_encoding () for details.
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
 * @error: A location to return an error of type #GIOChannelError
 *
 * Replacement for g_io_channel_seek() with the new API.
 *
 * Return value:
 **/
GIOStatus
g_io_channel_seek_position	(GIOChannel* channel,
				 glong       offset,
				 GSeekType   type,
				 GError    **error)
{
  GIOStatus status;

  /* For files, only one of the read and write buffers can contain data.
   * For sockets, both can contain data.
   */

  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail ((error == NULL) || (*error == NULL),
			G_IO_STATUS_ERROR);
808
  g_return_val_if_fail (channel->is_seekable, G_IO_STATUS_ERROR);
809
810
811
812

  switch (type)
    {
      case G_SEEK_CUR: /* The user is seeking relative to the head of the buffer */
813
        if (channel->use_buffer)
814
          {
815
816
            if (channel->do_encode && channel->encoded_read_buf
                && channel->encoded_read_buf->len > 0)
817
818
819
820
821
822
823
              {
                g_warning ("Seek type G_SEEK_CUR not allowed for this"
                  " channel's encoding.\n");
                return G_IO_STATUS_ERROR;
              }
          if (channel->read_buf)
            offset -= channel->read_buf->len;
824
825
          if (channel->encoded_read_buf)
            {
826
              g_assert (channel->encoded_read_buf->len == 0 || !channel->do_encode);
827
828
829
830
831
832
833
834

              /* If there's anything here, it's because the encoding is UTF-8,
               * so we can just subtract the buffer length, the same as for
               * the unencoded data.
               */

              offset -= channel->encoded_read_buf->len;
            }
835
          }
836
        break;
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
      case G_SEEK_SET:
      case G_SEEK_END:
        break;
      default:
        g_warning ("g_io_channel_seek_position: unknown seek type");
        return G_IO_STATUS_ERROR;
    }

  if (channel->use_buffer)
    {
      status = g_io_channel_flush (channel, error);
      if (status != G_IO_STATUS_NORMAL)
        return status;
    }

  status = channel->funcs->io_seek (channel, offset, type, error);

  if ((status == G_IO_STATUS_NORMAL) && (channel->use_buffer))
    {
856
857
      if (channel->read_buf)
        g_string_truncate (channel->read_buf, 0);
858
859
860
861
862
863
864
865

      /* Conversion state no longer matches position in file */
      if (channel->read_cd != (GIConv) -1)
        g_iconv (channel->read_cd, NULL, NULL, NULL, NULL);
      if (channel->write_cd != (GIConv) -1)
        g_iconv (channel->write_cd, NULL, NULL, NULL, NULL);

      if (channel->encoded_read_buf)
866
        {
867
868
          g_assert (channel->encoded_read_buf->len == 0 || !channel->do_encode);
          g_string_truncate (channel->encoded_read_buf, 0);
869
        }
870

871
872
873
874
      if (channel->partial_write_buf[0] != '\0')
        {
          g_warning ("Partial character at end of write buffer not flushed.\n");
          channel->partial_write_buf[0] = '\0';
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
        }
    }

  return status;
}

/**
 * g_io_channel_flush:
 * @channel: a #GIOChannel
 * @error: location to store an error of type #GIOChannelError
 *
 * Flush the write buffer for the GIOChannel.
 *
 * Return value: the status of the operation: One of
 *   G_IO_CHANNEL_NORMAL, G_IO_CHANNEL_AGAIN, or
 *   G_IO_CHANNEL_ERROR.
 **/
GIOStatus
g_io_channel_flush (GIOChannel	*channel,
		    GError     **error)
{
  GIOStatus status;
897
  gsize this_time = 1, bytes_written = 0;
898
899
900
901

  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail ((error == NULL) || (*error == NULL), G_IO_STATUS_ERROR);

902
  if (channel->write_buf == NULL || channel->write_buf->len == 0)
903
    return G_IO_STATUS_NORMAL;
904
905
906

  do
    {
907
908
      g_assert (this_time > 0);

909
910
911
912
913
914
915
      status = channel->funcs->io_write (channel,
                                      channel->write_buf->str + bytes_written,
                                      channel->write_buf->len - bytes_written,
                                      &this_time, error);
      bytes_written += this_time;
    }
  while ((bytes_written < channel->write_buf->len)
916
         && (status == G_IO_STATUS_NORMAL));
917
918
919

  g_string_erase (channel->write_buf, 0, bytes_written);

920
921
  return status;
}
922

923
924
925
926
927
928
929
930
/**
 * g_io_channel_set_buffered:
 * @channel: a #GIOChannel
 * @buffered: whether to set the channel buffered or unbuffered
 *
 * The buffering state can only be set if the channel's encoding
 * is %NULL. For any other encoding, the channel must be buffered.
 *
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
 * A buffered channel can only be set unbuffered if the channel's
 * internal buffers have been flushed. Newly created channels or
 * channels which have returned G_IO_STATUS_EOF
 * not require such a flush. For write-only channels, a call to
 * g_io_channel_flush () is sufficient. For all other channels,
 * the buffers may be flushed by a call to g_io_channel_seek_position ().
 * This includes the possibility of seeking with seek type %G_SEEK_CUR
 * and an offset of zero. Note that this means that socket-based
 * channels cannot be set unbuffered once they have had data
 * read from them.
 *
 * On unbuffered channels, it is safe to mix read and write
 * calls from the new and old APIs, if this is necessary for
 * maintaining old code.
 *
946
947
948
949
950
951
952
 * The default state of the channel is buffered.
 **/
void
g_io_channel_set_buffered	(GIOChannel *channel,
				 gboolean    buffered)
{
  g_return_if_fail (channel != NULL);
953

954
955
956
957
958
959
  if (channel->encoding != NULL)
    {
      g_warning ("Need to have NULL encoding to set the buffering state of the "
                 "channel.\n");
      return;
    }
960

961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
  g_return_if_fail (!channel->read_buf || channel->read_buf->len == 0);
  g_return_if_fail (!channel->write_buf || channel->write_buf->len == 0);

  channel->use_buffer = buffered;
}

/**
 * g_io_channel_get_buffered:
 * @channel: a #GIOChannel
 *
 * Return Value: the buffering state of the channel
 **/
gboolean
g_io_channel_get_buffered	(GIOChannel *channel)
{
  g_return_val_if_fail (channel != NULL, FALSE);

  return channel->use_buffer;
979
980
981
982
983
984
985
986
987
}

/**
 * g_io_channel_set_encoding:
 * @channel: a #GIOChannel
 * @encoding: the encoding type
 * @error: location to store an error of type #GConvertError.
 *
 * Set the encoding for the input/output of the channel. The internal
988
989
 * encoding is always UTF-8. The default encoding for the
 * external file is UTF-8.
990
 *
991
 * The encoding %NULL is safe to use with binary data.
992
 *
993
 * The encoding can only be set under the following conditions:
994
995
996
997
 *
 * 1. The channel was just created, and has not been written to
 *    or read from yet.
 *
998
999
1000
 * 2. The channel is write-only.
 *
 * 3. The channel is a file, and the file pointer was just
1001
1002
1003
 *    repositioned by a call to g_io_channel_seek_position().
 *    (This flushes all the internal buffers.)
 *
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
 * 4. The current encoding is %NULL or UTF-8.
 *
 * 5. One of the (new API) read functions has just returned G_IO_STATUS_EOF
 *    (or, in the case of g_io_channel_read_to_end (), G_IO_STATUS_NORMAL).
 *
 * 6. One of the functions g_io_channel_read_chars () or g_io_channel_read_unichar ()
 *    has returned G_IO_STATUS_AGAIN or G_IO_STATUS_ERROR. This may be
 *    useful in the case of G_CONVERT_ERROR_ILLEGAL_SEQUENCE.
 *    Returning one of these statuses from g_io_channel_read_line (),
 *    g_io_channel_read_line_string (), or g_io_channel_read_to_end ()
 *    does _not_ guarantee that the encoding can be changed.
 *
 * Channels which do not meet the above conditions cannot call
 * g_io_channel_seek_position () with an offset of %G_SEEK_CUR,
 * and if they are "seekable" cannot
 * call g_io_channel_write_chars () after calling one
 * of the API "read" functions.
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
 *
 * Return Value: %G_IO_STATUS_NORMAL if the encoding was succesfully set.
 **/
GIOStatus
g_io_channel_set_encoding (GIOChannel	*channel,
                           const gchar	*encoding,
			   GError      **error)
{
  GIConv read_cd, write_cd;
  gboolean did_encode;

  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail ((error == NULL) || (*error == NULL), G_IO_STATUS_ERROR);

1035
  /* Make sure the encoded buffers are empty */
1036

1037
  g_return_val_if_fail (!channel->do_encode || !channel->encoded_read_buf ||
1038
1039
			channel->encoded_read_buf->len == 0, G_IO_STATUS_ERROR);

1040
  if (!channel->use_buffer)
1041
    {
1042
1043
1044
      g_warning ("Need to set the channel buffered before setting the encoding.\n");
      g_warning ("Assuming this is what you meant and acting accordingly.\n");

1045
1046
      channel->use_buffer = TRUE;
    }
1047

1048
1049
1050
1051
1052
1053
  if (channel->partial_write_buf[0] != '\0')
    {
      g_warning ("Partial character at end of write buffer not flushed.\n");
      channel->partial_write_buf[0] = '\0';
    }

1054
1055
1056
  did_encode = channel->do_encode;

  if (!encoding || strcmp (encoding, "UTF8") == 0 || strcmp (encoding, "UTF-8") == 0)
1057
1058
    {
      channel->do_encode = FALSE;
1059
      read_cd = write_cd = (GIConv) -1;
1060
1061
1062
    }
  else
    {
1063
1064
      gint err = 0;
      const gchar *from_enc = NULL, *to_enc = NULL;
1065

1066
      if (channel->is_readable)
1067
        {
1068
1069
1070
1071
1072
1073
1074
1075
          read_cd = g_iconv_open ("UTF-8", encoding);

          if (read_cd == (GIConv) -1)
            {
              err = errno;
              from_enc = "UTF-8";
              to_enc = encoding;
            }
1076
1077
        }
      else
1078
1079
1080
        read_cd = (GIConv) -1;

      if (channel->is_writeable && err == 0)
1081
1082
        {
          write_cd = g_iconv_open (encoding, "UTF-8");
1083

1084
1085
1086
1087
1088
1089
1090
          if (write_cd == (GIConv) -1)
            {
              err = errno;
              from_enc = encoding;
              to_enc = "UTF-8";
            }
        }
1091
1092
      else
        write_cd = (GIConv) -1;
1093

1094
      if (err != 0)
1095
        {
1096
1097
1098
          g_assert (from_enc);
          g_assert (to_enc);

1099
1100
1101
1102
1103
1104
1105
          if (err == EINVAL)
            g_set_error (error, G_CONVERT_ERROR, G_CONVERT_ERROR_NO_CONVERSION,
                         _("Conversion from character set `%s' to `%s' is not supported"),
                         from_enc, to_enc);
          else
            g_set_error (error, G_CONVERT_ERROR, G_CONVERT_ERROR_FAILED,
                         _("Could not open converter from `%s' to `%s': %s"),
1106
                         from_enc, to_enc, strerror (err));
1107
1108
1109
1110
1111
1112

          if (read_cd != (GIConv) -1)
            g_iconv_close (read_cd);
          if (write_cd != (GIConv) -1)
            g_iconv_close (write_cd);

1113
1114
1115
1116
1117
1118
1119
1120
          return G_IO_STATUS_ERROR;
        }

      channel->do_encode = TRUE;
    }

  /* The encoding is ok, so set the fields in channel */

1121
1122
1123
1124
  if (channel->read_cd != (GIConv) -1)
    g_iconv_close (channel->read_cd);
  if (channel->write_cd != (GIConv) -1)
    g_iconv_close (channel->write_cd);
1125

1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
  if (channel->encoded_read_buf && channel->encoded_read_buf->len > 0)
    {
      g_assert (!did_encode); /* Encoding UTF-8, NULL doesn't use encoded_read_buf */

      /* This is just validated UTF-8, so we can copy it back into read_buf
       * so it can be encoded in whatever the new encoding is.
       */

      g_string_prepend_len (channel->read_buf, channel->encoded_read_buf->str,
                            channel->encoded_read_buf->len);
      g_string_truncate (channel->encoded_read_buf, 0);
    }

1139
1140
  channel->read_cd = read_cd;
  channel->write_cd = write_cd;
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152

  g_free (channel->encoding);
  channel->encoding = g_strdup (encoding);

  return G_IO_STATUS_NORMAL;
}

/**
 * g_io_channel_get_encoding:
 * @channel: a #GIOChannel
 *
 * Get the encoding for the input/output of the channel. The internal
1153
1154
 * encoding is always UTF-8. The encoding %NULL makes the
 * channel safe for binary data.
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
 *
 * Return value: A string containing the encoding, this string is
 *   owned by GLib and must not be freed.
 **/
G_CONST_RETURN gchar*
g_io_channel_get_encoding (GIOChannel      *channel)
{
  g_return_val_if_fail (channel != NULL, NULL);

  return channel->encoding;
}

static GIOStatus
g_io_channel_fill_buffer (GIOChannel *channel,
                          GError    **err)
{
  gsize read_size, cur_len, oldlen;
  GIOStatus status;

1174
  if (channel->is_seekable && channel->write_buf && channel->write_buf->len > 0)
1175
    {
1176
1177
1178
1179
1180
1181
1182
1183
      status = g_io_channel_flush (channel, err);
      if (status != G_IO_STATUS_NORMAL)
        return status;
    }
  if (channel->is_seekable && channel->partial_write_buf[0] != '\0')
    {
      g_warning ("Partial character at end of write buffer not flushed.\n");
      channel->partial_write_buf[0] = '\0';
1184
1185
    }

1186
1187
  if (!channel->read_buf)
    channel->read_buf = g_string_sized_new (channel->buf_size);
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205

  cur_len = channel->read_buf->len;

  g_string_set_size (channel->read_buf, channel->read_buf->len + channel->buf_size);

  status = channel->funcs->io_read (channel, channel->read_buf->str + cur_len,
                                    channel->buf_size, &read_size, err);

  g_assert ((status == G_IO_STATUS_NORMAL) || (read_size == 0));

  g_string_truncate (channel->read_buf, read_size + cur_len);

  if ((status != G_IO_STATUS_NORMAL)
    && ((status != G_IO_STATUS_EOF) || (channel->read_buf->len == 0)))
    return status;

  g_assert (channel->read_buf->len > 0);

1206
1207
1208
  if (channel->encoded_read_buf)
    oldlen = channel->encoded_read_buf->len;
  else
1209
1210
    {
      oldlen = 0;
1211
1212
      if (channel->encoding)
        channel->encoded_read_buf = g_string_sized_new (channel->buf_size);
1213
    }
1214

1215
1216
1217
1218
  if (channel->do_encode)
    {
      size_t errnum, inbytes_left, outbytes_left;
      gchar *inbuf, *outbuf;
1219
      int errval;
1220

1221
1222
      g_assert (channel->encoded_read_buf);

1223
1224
1225
reencode:

      inbytes_left = channel->read_buf->len;
1226
      outbytes_left = MAX (channel->read_buf->len,
1227
                           channel->encoded_read_buf->allocated_len
1228
1229
                           - channel->encoded_read_buf->len - 1); /* 1 for NULL */
      outbytes_left = MAX (outbytes_left, 6);
1230
1231

      inbuf = channel->read_buf->str;
1232
1233
      g_string_set_size (channel->encoded_read_buf,
                         channel->encoded_read_buf->len + outbytes_left);
1234
1235
      outbuf = channel->encoded_read_buf->str + channel->encoded_read_buf->len
               - outbytes_left;
1236
1237
1238

      errnum = g_iconv (channel->read_cd, &inbuf, &inbytes_left,
			&outbuf, &outbytes_left);
1239
1240
1241
1242
1243
1244
      errval = errno;

      g_assert (inbuf + inbytes_left == channel->read_buf->str
                + channel->read_buf->len);
      g_assert (outbuf + outbytes_left == channel->encoded_read_buf->str
                + channel->encoded_read_buf->len);
1245
1246
1247
1248
1249
1250
1251
1252

      g_string_erase (channel->read_buf, 0,
		      channel->read_buf->len - inbytes_left);
      g_string_truncate (channel->encoded_read_buf,
			 channel->encoded_read_buf->len - outbytes_left);

      if (errnum == (size_t) -1)
        {
1253
          switch (errval)
1254
1255
1256
1257
            {
              case EINVAL:
                if ((oldlen == channel->encoded_read_buf->len)
                  && (status == G_IO_STATUS_EOF))
1258
                  status = G_IO_STATUS_EOF;
1259
1260
1261
1262
                else
                  status = G_IO_STATUS_NORMAL;
                break;
              case E2BIG:
1263
1264
                /* Buffer size at least 6, wrote at least on character */
                g_assert (inbuf != channel->read_buf->str);
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
                goto reencode;
              case EILSEQ:
                if (oldlen < channel->encoded_read_buf->len)
                  status = G_IO_STATUS_NORMAL;
                else
                  {
                    g_set_error (err, G_CONVERT_ERROR,
                      G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
                      _("Invalid byte sequence in conversion input"));
                    return G_IO_STATUS_ERROR;
                  }
                break;
              default:
1278
                g_assert (errval != EBADF); /* The converter should be open */
1279
                g_set_error (err, G_CONVERT_ERROR, G_CONVERT_ERROR_FAILED,
1280
                  _("Error during conversion: %s"), strerror (errval));
1281
1282
1283
                return G_IO_STATUS_ERROR;
            }
        }
1284
1285
1286
1287
1288
1289
1290
      g_assert ((status != G_IO_STATUS_NORMAL)
               || (channel->encoded_read_buf->len > 0));
    }
  else if (channel->encoding) /* UTF-8 */
    {
      gchar *nextchar, *lastchar;

1291
1292
      g_assert (channel->encoded_read_buf);

1293
1294
1295
1296
      nextchar = channel->read_buf->str;
      lastchar = channel->read_buf->str + channel->read_buf->len;

      while (nextchar < lastchar)
1297
        {
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
          gunichar val_char;

          val_char = g_utf8_get_char_validated (nextchar, lastchar - nextchar);

          switch (val_char)
            {
              case -2:
                /* stop, leave partial character in buffer */
                lastchar = nextchar;
                break;
              case -1:
1309
                if (oldlen < channel->encoded_read_buf->len)
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
                  status = G_IO_STATUS_NORMAL;
                else
                  {
                    g_set_error (err, G_CONVERT_ERROR,
                      G_CONVERT_ERROR_ILLEGAL_SEQUENCE,
                      _("Invalid byte sequence in conversion input"));
                    status = G_IO_STATUS_ERROR;
                  }
                lastchar = nextchar;
                break;
              default:
                nextchar = g_utf8_next_char (nextchar);
                break;
            }
        }

      if (lastchar > channel->read_buf->str)
        {
          gint copy_len = lastchar - channel->read_buf->str;

          g_string_append_len (channel->encoded_read_buf, channel->read_buf->str,
                               copy_len);
          g_string_erase (channel->read_buf, 0, copy_len);
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
        }
    }

  return status;
}

/**
 * g_io_channel_read_line:
 * @channel: a #GIOChannel
 * @str_return: The line read from the #GIOChannel, not including the
 *              line terminator. This data should be freed with g_free()
 *              when no longer needed. This
 *              is a null terminated string. If a @length of zero is
 *              returned, this will be %NULL instead.
 * @length: location to store length of the read data, or %NULL
 * @terminator_pos: location to store position of line terminator, or %NULL
 * @error: A location to return an error of type #GConvertError
 *         or #GIOChannelError
 *
1352
 * Read a line, including the terminating character(s),
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
 * from a #GIOChannel into a newly allocated string.
 * @length will contain allocated memory if the return
 * is %G_IO_STATUS_NORMAL.
 *
 * Return value: a newly allocated string. Free this string
 *   with g_free() when you are done with it.
 **/
GIOStatus
g_io_channel_read_line (GIOChannel *channel,
                        gchar     **str_return,
                        gsize      *length,
			gsize      *terminator_pos,
		        GError    **error)
{
  GIOStatus status;
1368
  gsize got_length;
1369
1370
1371
1372
1373
  
  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail (str_return != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail ((error == NULL) || (*error == NULL),
			G_IO_STATUS_ERROR);
1374
  g_return_val_if_fail (channel->is_readable, G_IO_STATUS_ERROR);
1375

1376
1377
1378
1379
  status = g_io_channel_read_line_backend (channel, &got_length, terminator_pos, error);

  if (length)
    *length = got_length;
1380

1381
1382
  if (status == G_IO_STATUS_NORMAL)
    {
1383
1384
1385
      g_assert (USE_BUF (channel));
      *str_return = g_strndup (USE_BUF (channel)->str, got_length);
      g_string_erase (USE_BUF (channel), 0, got_length);
1386
    }
1387
  else
1388
    *str_return = NULL;
1389
1390
1391
1392
1393
1394
1395
1396
  
  return status;
}

/**
 * g_io_channel_read_line_string:
 * @channel: a #GIOChannel
 * @buffer: a #GString into which the line will be written.
1397
1398
 *          If @buffer already contains data, the old data will
 *          be overwritten.
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
 * @terminator_pos: location to store position of line terminator, or %NULL
 * @error: a location to store an error of type #GConvertError
 *         or #GIOChannelError
 *
 * Read a line from a #GIOChannel, using a #GString as a buffer.
 *
 * Return value:
 **/
GIOStatus
g_io_channel_read_line_string (GIOChannel *channel,
                               GString	  *buffer,
			       gsize      *terminator_pos,
                               GError	 **error)
{
1413
  gsize length;
1414
1415
1416
1417
1418
1419
  GIOStatus status;

  g_return_val_if_fail (channel != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail (buffer != NULL, G_IO_STATUS_ERROR);
  g_return_val_if_fail ((error == NULL) || (*error == NULL),
			G_IO_STATUS_ERROR);
1420
1421
1422
1423
1424
1425
1426
1427
1428
  g_return_val_if_fail (channel->is_readable, G_IO_STATUS_ERROR);

  if (buffer->len > 0)
    g_string_truncate (buffer, 0); /* clear out the buffer */

  status = g_io_channel_read_line_backend (channel, &length, terminator_pos, error);

  if (status == G_IO_STATUS_NORMAL)
    {
1429
1430
1431
      g_assert (USE_BUF (channel));
      g_string_append_len (buffer, USE_BUF (channel)->str, length);
      g_string_erase (USE_BUF (channel), 0, length);
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
    }

  return status;
}


static GIOStatus
g_io_channel_read_line_backend	(GIOChannel *channel,
				 gsize      *length,
				 gsize      *terminator_pos,
				 GError    **error)
{
  GIOStatus status;
  gsize checked_to, line_term_len, line_length, got_term_len;
  gboolean first_time = TRUE;

1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
  if (!channel->use_buffer)
    {
      /* Can't do a raw read in read_line */
      g_set_error (error, G_CONVERT_ERROR, G_CONVERT_ERROR_FAILED,
                   _("Can't do a raw read in g_io_channel_read_line_string"));
      return G_IO_STATUS_ERROR;
    }

  status = G_IO_STATUS_NORMAL;

  if (channel->line_term)
1459
    line_term_len = channel->line_term_len;
1460
  else
1461
1462
1463
1464
    line_term_len = 3;
    /* This value used for setting checked_to, it's the longest of the four
     * we autodetect for.
     */
1465
1466
1467
1468
1469

  checked_to = 0;

  while (TRUE)
    {
1470
      gchar *nextchar, *lastchar;
1471
      GString *use_buf;
1472

1473
      if (!first_time || (BUF_LEN (USE_BUF (channel)) == 0))
1474
        {
1475
read_again:
1476
1477
1478
1479
          status = g_io_channel_fill_buffer (channel, error);
          switch (status)
            {
              case G_IO_STATUS_NORMAL:
1480
                if (BUF_LEN (USE_BUF (channel)) == 0)
1481
1482
1483
1484
1485
1486
1487
                  /* Can happen when using conversion and only read
                   * part of a character
                   */
                  {
                    first_time = FALSE;
                    continue;
                  }
1488
1489
                break;
              case G_IO_STATUS_EOF:
1490
                if (BUF_LEN (USE_BUF (channel)) == 0)
1491
                  {
1492
1493
                    if (length)
                      *length = 0;
1494

1495
                    if (channel->encoding && channel->read_buf->len != 0)
1496
1497
1498
1499
1500
1501