Functions in GtkNotebook

GtkNotebook is a very important object in the text file editor tfe. It connects the application and TfeTextView objects. A set of public functions are declared in tfenotebook.h. The word “tfenotebook” is used only in filenames. There’s no “TfeNotebook” object.

void
notebook_page_save(GtkNotebook *nb);

void
notebook_page_close (GtkNotebook *nb);

void
notebook_page_open (GtkNotebook *nb);

void
notebook_page_new_with_file (GtkNotebook *nb, GFile *file);

void
notebook_page_new (GtkNotebook *nb);

This header file describes the public functions in tfenotebook.c.

You probably find that the functions except notebook_page_close are higher level functions of

respectively.

There are two layers. One of them is tfe_text_view ..., which is the lower level layer. The other is note_book ..., which is the higher level layer.

Now let’s look at the program of each function.

notebook_page_new

static gchar*
get_untitled () {
  static int c = -1;
  if (++c == 0) 
    return g_strdup_printf("Untitled");
  else
    return g_strdup_printf ("Untitled%u", c);
}

static void
notebook_page_build (GtkNotebook *nb, GtkWidget *tv, char *filename) {
  GtkWidget *scr = gtk_scrolled_window_new ();
  GtkNotebookPage *nbp;
  GtkWidget *lab;
  int i;

  gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (tv), GTK_WRAP_WORD_CHAR);
  gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (scr), tv);
  lab = gtk_label_new (filename);
  i = gtk_notebook_append_page (nb, scr, lab);
  nbp = gtk_notebook_get_page (nb, scr);
  g_object_set (nbp, "tab-expand", TRUE, NULL);
  gtk_notebook_set_current_page (nb, i);
  g_signal_connect (GTK_TEXT_VIEW (tv), "change-file", G_CALLBACK (file_changed_cb), nb);
}

void
notebook_page_new (GtkNotebook *nb) {
  g_return_if_fail(GTK_IS_NOTEBOOK (nb));

  GtkWidget *tv;
  char *filename;

  if ((tv = tfe_text_view_new ()) == NULL)
    return;
  filename = get_untitled ();
  notebook_page_build (nb, tv, filename);
}

notebook_page_new_with_file

void
notebook_page_new_with_file (GtkNotebook *nb, GFile *file) {
  g_return_if_fail(GTK_IS_NOTEBOOK (nb));
  g_return_if_fail(G_IS_FILE (file));

  GtkWidget *tv;
  char *filename;

  if ((tv = tfe_text_view_new_with_file (file)) == NULL)
    return; /* read error */
  filename = g_file_get_basename (file);
  notebook_page_build (nb, tv, filename);
}

notebook_page_open

static void
open_response (TfeTextView *tv, int response, GtkNotebook *nb) {
  GFile *file;
  char *filename;

  if (response != TFE_OPEN_RESPONSE_SUCCESS || ! G_IS_FILE (file = tfe_text_view_get_file (tv))) {
    g_object_ref_sink (tv);
    g_object_unref (tv);
  }else {
    filename = g_file_get_basename (file);
    g_object_unref (file);
    notebook_page_build (nb, GTK_WIDGET (tv), filename);
  }
}

void
notebook_page_open (GtkNotebook *nb) {
  g_return_if_fail(GTK_IS_NOTEBOOK (nb));

  GtkWidget *tv;

  if ((tv = tfe_text_view_new ()) == NULL)
    return;
  g_signal_connect (TFE_TEXT_VIEW (tv), "open-response", G_CALLBACK (open_response), nb);
  tfe_text_view_open (TFE_TEXT_VIEW (tv), GTK_WINDOW (gtk_widget_get_ancestor (GTK_WIDGET (nb), GTK_TYPE_WINDOW)));
}

All the widgets are derived from GInitiallyUnowned. When an instance of GInitiallyUnowned or its descendant is created, the instance has a floating reference. The function g_object_ref_sink converts the floating reference into an ordinary reference. If the instance doesn’t have a floating reference, g_object_ref_sink simply increases the reference count by one. On the other hand, when an instance of GObject (not GInitiallyUnowned) is created, no floating reference is given. And the instance has a normal reference count instead of floating reference.

If you use g_object_unref to an instance that has a floating reference, you need to convert the floating reference to a normal reference in advance. See GObject Reference Manual for further information.

notebook_page_close

void
notebook_page_close (GtkNotebook *nb) {
  g_return_if_fail(GTK_IS_NOTEBOOK (nb));

  GtkWidget *win;
  int i;

  if (gtk_notebook_get_n_pages (nb) == 1) {
    win = gtk_widget_get_ancestor (GTK_WIDGET (nb), GTK_TYPE_WINDOW);
    gtk_window_destroy(GTK_WINDOW (win));
  } else {
    i = gtk_notebook_get_current_page (nb);
    gtk_notebook_remove_page (GTK_NOTEBOOK (nb), i);
  }
}

This function closes the current page. If the page is the only page the notebook has, then the function destroys the top-level window and quits the application.

notebook_page_save

static TfeTextView *
get_current_textview (GtkNotebook *nb) {
  int i;
  GtkWidget *scr;
  GtkWidget *tv;

  i = gtk_notebook_get_current_page (nb);
  scr = gtk_notebook_get_nth_page (nb, i);
  tv = gtk_scrolled_window_get_child (GTK_SCROLLED_WINDOW (scr));
  return TFE_TEXT_VIEW (tv);
}

void
notebook_page_save (GtkNotebook *nb) {
  g_return_if_fail(GTK_IS_NOTEBOOK (nb));

  TfeTextView *tv;

  tv = get_current_textview (nb);
  tfe_text_view_save (TFE_TEXT_VIEW (tv));
}

file_changed_cb handler

The function file_changed_cb is a handler connected to “change-file” signal. If a file in a TfeTextView instance is changed, it emits this signal. This handler changes the label of GtkNotebookPage.

static void
file_changed_cb (TfeTextView *tv, GtkNotebook *nb) {
  GtkWidget *scr;
  GtkWidget *label;
  GFile *file;
  char *filename;

  file = tfe_text_view_get_file (tv);
  scr = gtk_widget_get_parent (GTK_WIDGET (tv));
  if (G_IS_FILE (file)) {
    filename = g_file_get_basename (file);
    g_object_unref (file);
  } else
    filename = get_untitled ();
  label = gtk_label_new (filename);
  g_free (filename);
  gtk_notebook_set_tab_label (nb, scr, label);
}