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 related to GtkNotebook are declared in tfenotebook.h. The word "tfenotebook" is used only in filenames. There's no "TfeNotebook" object.

 1 void
 2 notebook_page_save(GtkNotebook *nb);
 3 
 4 void
 5 notebook_page_close (GtkNotebook *nb);
 6 
 7 void
 8 notebook_page_open (GtkNotebook *nb);
 9 
10 void
11 notebook_page_new_with_file (GtkNotebook *nb, GFile *file);
12 
13 void
14 notebook_page_new (GtkNotebook *nb);
15

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

1-2: notebook_page_save saves the current page to the file of which the name specified in the tab. If the name is untitled or untitled followed by digits, FileChooserDialog appears and a user can choose or specify a filename.
4-5: notebook_page_close closes the current page.
7-8: notebook_page_open shows a file chooser dialog and a user can choose a file. The file is inserted to a new page.
10-11: notebook_page_new_with_file generates a new page and the file give as an argument is read and inserted into the page.
13-14: notebook_page_new generates a new empty page.

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

tfe_text_view_save
tef_text_view_open
tfe_text_view_new_with_file
tfe_text_view_new

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

 1 static gchar*
 2 get_untitled () {
 3   static int c = -1;
 4   if (++c == 0) 
 5     return g_strdup_printf("Untitled");
 6   else
 7     return g_strdup_printf ("Untitled%u", c);
 8 }
 9 
10 static void
11 notebook_page_build (GtkNotebook *nb, GtkWidget *tv, char *filename) {
12   GtkWidget *scr = gtk_scrolled_window_new ();
13   GtkNotebookPage *nbp;
14   GtkWidget *lab;
15   int i;
16 
17   gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (tv), GTK_WRAP_WORD_CHAR);
18   gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (scr), tv);
19   lab = gtk_label_new (filename);
20   i = gtk_notebook_append_page (nb, scr, lab);
21   nbp = gtk_notebook_get_page (nb, scr);
22   g_object_set (nbp, "tab-expand", TRUE, NULL);
23   gtk_notebook_set_current_page (nb, i);
24   g_signal_connect (GTK_TEXT_VIEW (tv), "change-file", G_CALLBACK (file_changed_cb), nb);
25 }
26 
27 void
28 notebook_page_new (GtkNotebook *nb) {
29   g_return_if_fail(GTK_IS_NOTEBOOK (nb));
30 
31   GtkWidget *tv;
32   char *filename;
33 
34   tv = tfe_text_view_new ();
35   filename = get_untitled ();
36   notebook_page_build (nb, tv, filename);
37 }

27-37: notebook_page_new function.
29: g_return_if_fail is used to check the argument.
34: Generates TfeTextView object.
35: Generates filename, which is "Untitled", "Untitled1", ... .
1-8: get_untitled function.
3: Static variable c is initialized at the first call of this function. After that c keeps its value unless it is changed explicitly.
4-7: Increases c by one and if it is zero then it returns "Untitled". If it is a positive integer then it returns "Untitled<the integer>", for example, "Untitled1", "Untitled2", and so on. The function g_strdup_printf generates a string and it should be freed by g_free when it becomes useless. The caller of get_untitled is in charge of freeing the string.
36: calls notebook_page_build to build the contents of the page.
10- 25: notebook_page_build function.
12: Generates GtkScrolledWindow.
17: Sets the wrap mode of tv to GTK_WRAP_WORD_CHAR so that lines are broken between words or graphemes.
18: Inserts tv to GtkscrolledWindow as a child.
19-20: Generates GtkLabel, then appends it to GtkNotebookPage.
21-22: Sets "tab-expand" property to TRUE. The function g_object_set sets properties on an object. The object is any object derived from GObject. In many cases, an object has its own function to set its properties, but sometimes not. In that case, use g_object_set to set the property.
23: Sets the current page of nb to the newly generated page.
24: Connects "change-file" signal and file_changed_cb handler.

notebook_page_new_with_file

 1 void
 2 notebook_page_new_with_file (GtkNotebook *nb, GFile *file) {
 3   g_return_if_fail(GTK_IS_NOTEBOOK (nb));
 4   g_return_if_fail(G_IS_FILE (file));
 5 
 6   GtkWidget *tv;
 7   char *filename;
 8 
 9   if ((tv = tfe_text_view_new_with_file (file)) == NULL)
10     return; /* read error */
11   filename = g_file_get_basename (file);
12   notebook_page_build (nb, tv, filename);
13 }

9-10: Calls tfe_text_view_new_with_file. If the function returns NULL, then it does nothing and returns. The return value NULL means that an error has happened.
11-12: Gets the filename and builds the contents of the page.

notebook_page_open

 1 static void
 2 open_response (TfeTextView *tv, int response, GtkNotebook *nb) {
 3   GFile *file;
 4   char *filename;
 5 
 6   if (response != TFE_OPEN_RESPONSE_SUCCESS) {
 7     g_object_ref_sink (tv);
 8     g_object_unref (tv);
 9   }else if (! G_IS_FILE (file = tfe_text_view_get_file (tv))) {
10     g_object_ref_sink (tv);
11     g_object_unref (tv);
12   }else {
13     filename = g_file_get_basename (file);
14     g_object_unref (file);
15     notebook_page_build (nb, GTK_WIDGET (tv), filename);
16   }
17 }
18 
19 void
20 notebook_page_open (GtkNotebook *nb) {
21   g_return_if_fail(GTK_IS_NOTEBOOK (nb));
22 
23   GtkWidget *tv;
24 
25   tv = tfe_text_view_new ();
26   g_signal_connect (TFE_TEXT_VIEW (tv), "open-response", G_CALLBACK (open_response), nb);
27   tfe_text_view_open (TFE_TEXT_VIEW (tv), GTK_WINDOW (gtk_widget_get_ancestor (GTK_WIDGET (nb), GTK_TYPE_WINDOW)));
28 }

19-28: notebook_page_open function.
25: Generates TfeTextView object.
26: Connects the signal "open-response" and the handler open_response.
27: Calls tfe_text_view_open. The function emits an "open-response" signal to inform the status.
1-17: open_response handler. This is the post-function of notebook_page_open.
6-8: If the status is NOT TFE_OPEN_RESPONSE_SUCCESS, it cancels what it did in notebook_page_open. The object tv hasn't been a child widget of some other widget yet. Such object has floating reference. You need to call g_object_ref_sink first. Then the floating reference is converted into an ordinary reference. Now you call g_object_unref to decrease the reference count by one.
9-11: If tfe_text_view_get_file returns a pointer not to point GFile, it means that an error has happened. Sink and unref tv.
12-16: Otherwise, everything is okay. Gets the filename, builds the contents of the page.

notebook_page_close

 1 void
 2 notebook_page_close (GtkNotebook *nb) {
 3   g_return_if_fail(GTK_IS_NOTEBOOK (nb));
 4 
 5   GtkWidget *win;
 6   int i;
 7 
 8   if (gtk_notebook_get_n_pages (nb) == 1) {
 9     win = gtk_widget_get_ancestor (GTK_WIDGET (nb), GTK_TYPE_WINDOW);
10     gtk_window_destroy(GTK_WINDOW (win));
11   } else {
12     i = gtk_notebook_get_current_page (nb);
13     gtk_notebook_remove_page (GTK_NOTEBOOK (nb), i);
14   }
15 }

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

8-10: If the page is the only page the notebook has, it calls gtk_window_destroy to destroys the top window.
11-13: Otherwise, removes the current page.

notebook_page_save

 1 static TfeTextView *
 2 get_current_textview (GtkNotebook *nb) {
 3   int i;
 4   GtkWidget *scr;
 5   GtkWidget *tv;
 6 
 7   i = gtk_notebook_get_current_page (nb);
 8   scr = gtk_notebook_get_nth_page (nb, i);
 9   tv = gtk_scrolled_window_get_child (GTK_SCROLLED_WINDOW (scr));
10   return TFE_TEXT_VIEW (tv);
11 }
12 
13 void
14 notebook_page_save (GtkNotebook *nb) {
15   g_return_if_fail(GTK_IS_NOTEBOOK (nb));
16 
17   TfeTextView *tv;
18 
19   tv = get_current_textview (nb);
20   tfe_text_view_save (TFE_TEXT_VIEW (tv));
21 }

13-21: notebook_page_save.
19: Gets TfeTextView belongs to the current page.
20: Calls tfe_text_view_save.
1-11: get_current_textview. This function gets the TfeTextView object belongs to the current page.
7: Gets the page number of the current page.
8: Gets the child object scr, which is GtkScrolledWindow object, of the current page.
9-10: Gets the child object of scr, which is TfeTextView object, and return it.

file_changed_cb handler

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

 1 static void
 2 file_changed_cb (TfeTextView *tv, GtkNotebook *nb) {
 3   GtkWidget *scr;
 4   GtkWidget *label;
 5   GFile *file;
 6   char *filename;
 7 
 8   file = tfe_text_view_get_file (tv);
 9   scr = gtk_widget_get_parent (GTK_WIDGET (tv));
10   if (G_IS_FILE (file)) {
11     filename = g_file_get_basename (file);
12     g_object_unref (file);
13   } else
14     filename = get_untitled ();
15   label = gtk_label_new (filename);
16   gtk_notebook_set_tab_label (nb, scr, label);
17 }

8: Gets GFile from TfeTextView.
9: Gets GkScrolledWindow which is the parent widget of tv.
10-12: If file points GFile, then assigns the filename of the GFile into filename. Then, unref the GFile object file.
13-14: Otherwise (file is NULL), assigns untitled string to filename.
15-16: Generates a label with the filename and inserts it into GtkNotebookPage.

The string filename is used in the GtkLabel object. You mustn't free it.

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