static void
sysroot_output_cb (RpmOstreeOutputType type, void *data, void *opaque)
{
  RpmostreedSysroot *self = RPMOSTREED_SYSROOT (opaque);
  glnx_unref_object RpmostreedTransaction *transaction = NULL;

  transaction =
    rpmostreed_transaction_monitor_ref_active_transaction (self->transaction_monitor);

  if (!transaction)
    {
      rpmostree_output_default_handler (type, data, opaque);
      return;
    }

  switch (type)
  {
  case RPMOSTREE_OUTPUT_TASK_BEGIN:
    rpmostree_transaction_emit_task_begin (RPMOSTREE_TRANSACTION (transaction),
                                           ((RpmOstreeOutputTaskBegin*)data)->text);
    break;
  case RPMOSTREE_OUTPUT_TASK_END:
    rpmostree_transaction_emit_task_end (RPMOSTREE_TRANSACTION (transaction),
                                         ((RpmOstreeOutputTaskEnd*)data)->text);
    break;
  case RPMOSTREE_OUTPUT_PERCENT_PROGRESS:
    rpmostree_transaction_emit_percent_progress (RPMOSTREE_TRANSACTION (transaction),
                                                 ((RpmOstreeOutputPercentProgress*)data)->text,
                                                 ((RpmOstreeOutputPercentProgress*)data)->percentage);
    break;
  case RPMOSTREE_OUTPUT_PERCENT_PROGRESS_END:
    rpmostree_transaction_emit_progress_end (RPMOSTREE_TRANSACTION (transaction));
    break;
  }
}
static RpmostreedTransaction *
merge_compatible_txn (RpmostreedOSExperimental *self,
                      GDBusMethodInvocation *invocation)
{
  glnx_unref_object RpmostreedTransaction *transaction = NULL;

  /* If a compatible transaction is in progress, share its bus address. */
  transaction = rpmostreed_transaction_monitor_ref_active_transaction (self->transaction_monitor);
  if (transaction != NULL)
    {
      if (rpmostreed_transaction_is_compatible (transaction, invocation))
        return g_steal_pointer (&transaction);
    }

  return NULL;
}
static gboolean
sysroot_stdout_ready_cb (GPollableInputStream *pollable_stream,
                         StdoutClosure *closure)
{
  glnx_unref_object RpmostreedSysroot *sysroot = NULL;
  glnx_unref_object RpmostreedTransaction *transaction = NULL;
  GMemoryInputStream *memory_stream;
  GBufferedInputStream *buffered_stream;
  char buffer[1024];
  gconstpointer stream_buffer;
  gsize stream_buffer_size;
  gsize total_bytes_read = 0;
  gboolean have_line = FALSE;
  GError *local_error = NULL;

  sysroot = g_weak_ref_get (&closure->sysroot);
  if (sysroot != NULL)
    transaction = rpmostreed_transaction_monitor_ref_active_transaction (sysroot->transaction_monitor);

  /* XXX Would very much like g_buffered_input_stream_fill_nonblocking().
   *     Much of this function is a clumsy and inefficient attempt to
   *     achieve the same thing.
   *
   *     See: https://bugzilla.gnome.org/726797
   */

  buffered_stream = G_BUFFERED_INPUT_STREAM (closure->data_stream);
  memory_stream = (GMemoryInputStream *) g_filter_input_stream_get_base_stream (G_FILTER_INPUT_STREAM (buffered_stream));

  while (local_error == NULL)
    {
      gssize n_read;

      n_read = g_pollable_input_stream_read_nonblocking (pollable_stream,
                                                         buffer,
                                                         sizeof (buffer),
                                                         NULL, &local_error);

      if (n_read > 0)
        {
          /* XXX Gotta use GBytes so the data gets copied. */
          g_autoptr(GBytes) bytes = g_bytes_new (buffer, n_read);
          g_memory_input_stream_add_bytes (memory_stream, bytes);
          total_bytes_read += n_read;
        }
    }

  if (!g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK))
    goto out;

  g_clear_error (&local_error);

read_another_line:

  /* Fill the buffered stream with the data we just put in the
   * memory stream, then peek at the buffer to see if it's safe
   * to call g_data_input_stream_read_line() without blocking.
   *
   * XXX Oye, there's gotta be an easier way to do this...
   */

  /* This should never fail since it's just reading from memory. */
  g_buffered_input_stream_fill (buffered_stream, total_bytes_read, NULL, NULL);

  stream_buffer = g_buffered_input_stream_peek_buffer (buffered_stream, &stream_buffer_size);
  have_line = (memchr (stream_buffer, '\n', stream_buffer_size) != NULL);

  if (have_line)
    {
      g_autofree char *line = NULL;
      gsize length;

      line = g_data_input_stream_read_line (closure->data_stream,
                                            &length, NULL, &local_error);

      if (local_error != NULL)
        goto out;

      /* If there's an active transaction, forward the line to the
       * transaction's owner through the "Message" signal.  Otherwise
       * dump it to the non-redirected standard output stream. */
      if (transaction != NULL)
        {
          rpmostree_transaction_emit_message (RPMOSTREE_TRANSACTION (transaction), line);
        }
      else
        {
          /* This is essentially puts(), don't care about errors. */
          g_output_stream_write_all (closure->real_stdout,
                                     line, length, NULL, NULL, NULL);
          g_output_stream_write_all (closure->real_stdout,
                                     "\n", 1, NULL, NULL, NULL);
        }

      goto read_another_line;
    }

out:
  if (local_error != NULL)
    {
      g_warning ("Failed to read stdout pipe: %s", local_error->message);
      g_clear_error (&local_error);
    }

  return G_SOURCE_CONTINUE;
}