Functions with GtkNotebook

GtkNotebook is a very important object in the text file editor tfe. It connects the application and TfeTextView objects. tfenotebook.h and tfenotebook.c describe a set of functions related to GtkTextbook.

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

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

notebook_page_new generates a new GtkNotebookPage and adds GtkScrolledWindow and TfeTextView under the page.
notebook_page_new_with_file generates a new GtkNotebookPage and adds GtkScrolledWindow and TfeTextView under the page. file is set to the pointer to GFile in the TfeTextView object and the file is read and set into GtkTextBuffer.
notebook_page_open lets the user select a file and sets it into GtkTextBuffer.
notebook_page_save save the contents in GtkTextBuffer to a file, using the pointer tv->file.

You probably find that the functions above are higher level functions of tfe_text_view_new, tfe_text_view_new_with_file, tef_text_view_open and tfe_text_view_save 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 each program of the functions.

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;
13   GtkNotebookPage *nbp;
14   GtkWidget *lab;
15   gint i;
16   scr = gtk_scrolled_window_new ();
17 
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), 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 because notebook_page_new is a public function.
34: Generate TfeTextView object.
35: Generate filename, which is "Untitled", "Untitled2", ... .
1-8: get_untitled function.
3: Static variable c is initialized at the first call of this function. After that c keeps its value except it is changed explicitly.
4-7: Increase c by one and if it is zero then the name is "Untitled". If it is a positive integer then the name is "Untitled", for example, "Untitled1", "Untitled2", and so on. It returns the name. g_strdup_printf generates a string and it should be freed by g_free function. The caller of get_untitled is in charge of freeing the memories of the string.
36: call notebook_page_build to build the contents of the page.
10- 25: notebook_page_build function.
17-18: Generate GtkScrolledWindow and set tv to its child.
19-20: Generate GtkLabel, then GtkNotebookPage.
21-22: Set "tab-expand" property to TRUE.
23: Set the page to the current page.
24: Connect "change-file" signal and file_changed 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: Call tfe_text_view_new_with_file. If it returns NULL, then do nothing and return because of an error. -11-13: Get the filename , build the contents of the page, then free filename.

notebook_page_open

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

18-27: notebook_page_open function.
24: Generate TfeTextView object.
25: Connect the signal "open-response" and the handler open_response.
26: Call tfe_text_view_open. It emits "open-response" signal to inform the status after the series of functions run.
1-16: open_response handler. This is the postfunction of notebook_page_open.
6-7: It the status is NOT TFE_OPEN_RESPONSE_SUCCESS, cancel what we did in notebook_page_open. Unref tv.
8-9: If tfe_text_view_get_file returns a pointer not to point GFile, then something bad happens. Cancel what we did. Unref tv.
10-14: Otherwise, everything was okay. Get the filename, build the contents of the page, free filename and unref tv

notebook_page_save

 1 void
 2 notebook_page_save(GtkNotebook *nb) {
 3   gint 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   tfe_text_view_save (TFE_TEXT_VIEW (tv));
11 }

7-9: Get TfeTextView belongs to the current notebook page.
10: Call tfe_text_view_save.

file_changed handler

file_changed is a handler connected to "change-file" signal. If tv->file is changed, TfeTextView emits this signal. This handler changes the label of GtkNotebookPage.

 1 static void
 2 file_changed (TfeTextView *tv, GtkNotebook *nb) {
 3   GFile *file;
 4   char *filename;
 5   GtkWidget *scr;
 6   GtkWidget *label;
 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   else
13     filename = get_untitled ();
14   label = gtk_label_new (filename);
15   gtk_notebook_set_tab_label (nb, scr, label);
16   g_object_unref (file);
17   g_free (filename);
18 }

8: Get GFile from TfeTextView.
9: Get the parent (GkScrolledWindow) of tv.
10-13: If file points GFile, then assign the filename of the GFile into filename. Otherwise (this is the case file is NULL), assign untitled string to filename.
14-15: Generate a label with the filename and set it into GtkNotebookPage.
16-17: Free filename and unref file`.

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