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 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_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 describes the public functions in tfenotebook.c.

10-11: The function notebook_page_new generates a new GtkNotebookPage and adds GtkScrolledWindow and TfeTextView to the page.
7-8: The function notebook_page_new_with_file generates a new GtkNotebookPage and adds GtkScrolledWindow and TfeTextView to the page. A file is read and inserted into GtkTextBuffer. The GFile file is copied and inserted to the TfeTextView object.
4-5: notebook_page_open shows a file chooser dialog. Then, user chooses a file and the file is inserted into GtkTextBuffer.
1-2: notebook_page_save saves the contents in GtkTextBuffer into the file, which is got from the TfeTextView.

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
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_text_view_set_wrap_mode (GTK_TEXT_VIEW (tv), GTK_WRAP_WORD_CHAR);
19   gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (scr), tv);
20   lab = gtk_label_new (filename);
21   i = gtk_notebook_append_page (nb, scr, lab);
22   nbp = gtk_notebook_get_page (nb, scr);
23   g_object_set (nbp, "tab-expand", TRUE, NULL);
24   gtk_notebook_set_current_page (nb, i);
25   g_signal_connect (GTK_TEXT_VIEW (tv), "change-file", G_CALLBACK (file_changed), nb);
26 }
27 
28 void
29 notebook_page_new (GtkNotebook *nb) {
30   g_return_if_fail(GTK_IS_NOTEBOOK (nb));
31 
32   GtkWidget *tv;
33   char *filename;
34 
35   tv = tfe_text_view_new ();
36   filename = get_untitled ();
37   notebook_page_build (nb, tv, filename);
38 }

28-38: notebook_page_new function.
30: g_return_if_fail is used to check the argument.
35: Generates TfeTextView object.
36: Generates 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: Increases c by one and if it is zero then it returns "Untitled". If it is a positive integer then the 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.
37: calls notebook_page_build to build the contents of the page.
10- 26: notebook_page_build function.
16: Generates GtkScrolledWindow.
18: Sets the wrap mode of tv to GTK_WRAP_WORD_CHAR so that lines are broken between words or graphemes.
19: Inserts tv to GtkscrolledWindow as a child.
20-21: Generates GtkLabel, then appends it to GtkNotebookPage.
22-23: 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.
24: Sets the current page of nb to i which is the number of the GtkNotebookPage above.
25: Connects "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: 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, gint 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_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, then something bad happens. Sink and unref tv.
12-16: Otherwise, everything is okay. Gets the filename, builds the contents of the page.

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

The function file_changed 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 (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: Gets GFile from TfeTextView.
9: Gets GkScrolledWindow which is the parent widget of tv.
10-13: If file points GFile, then assigns the filename of the GFile into filename. Otherwise (file is NULL), assigns untitled string to filename.
14-15: Generates a label with the filename and inserts it into GtkNotebookPage.
16-17: Unrefs file and frees filename.

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