giochannel.c

嵌入式下基于MiniGUI的Web Browser

            }
          }
        break;
      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))
    {
      if (channel->read_buf)
        g_string_truncate (channel->read_buf, 0);

      /* 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)
        {
          g_assert (channel->encoded_read_buf->len == 0 || !channel->do_encode);
          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';
        }
    }

  return status;
}

/**
 * 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.
 *
 * 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.
 *
 * The default state of the channel is buffered.
 **/
void
g_io_channel_set_buffered	(GIOChannel *channel,
				 gboolean    buffered)
{
  g_return_if_fail (channel != NULL);

  if (channel->encoding != NULL)
    {
      g_warning ("Need to have NULL encoding to set the buffering state of the "
                 "channel.\n");
      return;
    }

  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.
 *
 * Returns whether @channel is buffered.
 *
 * Return Value: %TRUE if the @channel is buffered. 
 **/
gboolean
g_io_channel_get_buffered	(GIOChannel *channel)
{
  g_return_val_if_fail (channel != NULL, FALSE);

  return channel->use_buffer;
}

/**
 * g_io_channel_set_encoding:
 * @channel: a #GIOChannel
 * @encoding: the encoding type
 * @error: location to store an error of type #GConvertError.
 *
 * Sets the encoding for the input/output of the channel. The internal
 * encoding is always UTF-8. The default encoding for the
 * external file is UTF-8.
 *
 * The encoding %NULL is safe to use with binary data.
 *
 * The encoding can only be set if one of the following conditions
 * is true:
 *
 * 1. The channel was just created, and has not been written to
 *    or read from yet.
 *
 * 2. The channel is write-only.
 *
 * 3. The channel is a file, and the file pointer was just
 *    repositioned by a call to g_io_channel_seek_position().
 *    (This flushes all the internal buffers.)
 *
 * 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 <emphasis>not</emphasis> guarantee that the encoding can be changed.
 *
 * Channels which do not meet one of 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.
 *
 * Return Value: %G_IO_STATUS_NORMAL if the encoding was successfully 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);

  /* Make sure the encoded buffers are empty */

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

  if (!channel->use_buffer)
    {
      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");

      channel->use_buffer = TRUE;
    }

  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';
    }

  did_encode = channel->do_encode;

  if (!encoding || strcmp (encoding, "UTF8") == 0 || strcmp (encoding, "UTF-8") == 0)
    {
      channel->do_encode = FALSE;
      read_cd = write_cd = (GIConv) -1;
    }
  else
    {
      gint err = 0;
      const gchar *from_enc = NULL, *to_enc = NULL;

      if (channel->is_readable)
        {
          read_cd = g_iconv_open ("UTF-8", encoding);

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

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

          if (write_cd == (GIConv) -1)
            {
              err = errno;
              from_enc = encoding;
              to_enc = "UTF-8";
            }
        }
      else
        write_cd = (GIConv) -1;

      if (err != 0)
        {
          g_assert (from_enc);
          g_assert (to_enc);

          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"),
                         from_enc, to_enc, g_strerror (err));

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

          return G_IO_STATUS_ERROR;
        }

      channel->do_encode = TRUE;
    }

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

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

  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);
    }

  channel->read_cd = read_cd;
  channel->write_cd = write_cd;

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

  return G_IO_STATUS_NORMAL;
}

/**
 * g_io_channel_get_encoding:
 * @channel: a #GIOChannel
 *
 * Gets the encoding for the input/output of the channel. The internal
 * encoding is always UTF-8. The encoding %NULL makes the
 * channel safe for binary data.
 *
 * 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;

  if (channel->is_seekable && channel->write_buf && channel->write_buf->len > 0)
    {
      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';
    }

  if (!channel->read_buf)
    channel->read_buf = g_string_sized_new (channel->buf_size);

  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);

  if (channel->encoded_read_buf)
    oldlen = channel->encoded_read_buf->len;
  else
    {
      oldlen = 0;
      if (channel->encoding)
        channel->encoded_read_buf = g_string_sized_new (channel->buf_size);
    }

  if (channel->do_encode)
    {
      size_t errnum, inbytes_left, outbytes_left;
      gchar *inbuf, *outbuf;
      int errval;

      g_assert (channel->encoded_read_buf);

reencode:

      inbytes_left = channel->read_buf->len;
      outbytes_left = MAX (channel->read_buf->len,
                           channel->encoded_read_buf->allocated_len
                           - channel->encoded_read_buf->len - 1); /* 1 for NULL */
      outbytes_left = MAX (outbytes_left, 6);

      inbuf = channel->read_buf->str;
      g_string_set_size (channel->encoded_read_buf,
                         channel->encoded_read_buf->len + outbytes_left);
      outbuf = channel->encoded_read_buf->str + channel->encoded_read_buf->len
               - outbytes_left;

      errnum = g_iconv (channel->read_cd, &inbuf, &inbytes_left,
			&outbuf, &outbytes_left);
      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);

      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)
        {
          switch (errval)
            {
              case EINVAL:
                if ((oldlen == channel->encoded_read_buf->len)
                  && (status == G_IO_STATUS_EOF))
                  status = G_IO_STATUS_EOF;
                else
                  status = G_IO_STATUS_NORMAL;
                break;
              case E2BIG:
                /* Buffer size at least 6, wrote at least on character */
                g_assert (inbuf != channel->read_buf->str);
                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:
                g_assert (errval != EBADF); /* The converter should be open */
                g_set_error (err, G_CONVERT_ERROR, G_CONVERT_ERROR_FAILED,
                  _("Error during conversion: %s"), g_strerror (errval));
                return G_IO_STATUS_ERROR;
            }
        }
      g_assert ((status != G_IO_STATUS_NORMAL)
               || (channel->encoded_read_buf->len > 0));
    }
  else if (channel->encoding) /* UTF-8 */
    {
      gchar *nextchar, *lastchar;

      g_assert (channel->encoded_read_buf);

      nextchar = channel->read_buf->str;
      lastchar = channel->read_buf->str + channel->read_buf->len;

      while (nextchar < lastchar)
        {
          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: