Re: gtk_label_get_text() string duping

[Owen Taylor <otaylor redhat com>]

To provide some hard data, here is most (I.e., what I could find
quickly) of the functions from glib/pango/gtk+ that return char *.

I've separated out the functions where by their very nature they need
to copy or not copy. (g_strdup, or g_utf8_next_char.)

The allocing functions outnumber the non-allocing functions about 44
to 30, though it could be argued that most of the allocing functions
alloc because they have to. (Only 10 or so are just g_strdup's of an
internal field.)

However, I don't think that rational gives the user much sense of
consistency - is it obvious that gtk_widget_name() doesn't need to
copy, but gtk_container_composite_child_name() does? is it obvious
that g_module_error() doesn't need to copy but g_win32_error_message()
does?

(This was one of two reasons that I thought we had decided on
copy-everything - in many cases you _do_ need to copy and the user
can't always know which ones. The other reason was thread safety,
especially in glib where we don't have a global lock.)

I'm not going to give an opinion on what we should do tonight - just
thought I'd throw some data out there.

Regards,
                                        Owen


No-alloc
=======

gchar* gdk_set_locale                      (void);
gchar* gdk_get_display                     (void);
gchar* gdk_keyval_name                     (guint              keyval);
gchar* gtk_arg_name_strip_type             (const gchar       *arg_name);
gchar *gtk_clist_get_column_title          (GtkCList          *clist,
					    gint               column);
gint   gtk_clist_get_text                  (GtkCList          *clist,
					    gint               row,
					    gint               column,
					    gchar            **text);
gint   gtk_clist_get_pixtext               (GtkCList          *clist,
					    gint               row,
					    gint               column,
					    gchar            **text,
					    guint8            *spacing,
					    GdkPixmap        **pixmap,
					    GdkBitmap        **mask);
gchar* gtk_entry_get_text                  (GtkEntry          *entry);
void   gtk_label_get                       (GtkLabel          *label,
					    char             **str);
gchar* gtk_set_locale                      (void);
gchar* gtk_file_selection_get_filename     (GtkFileSelection  *filesel);
gchar* gtk_font_selection_get_preview_text (GtkFontSelection  *fontsel);

gchar* gtk_font_selection_dialog_get_preview_text (GtkFontSelectionDialog *fsd);

gchar*       gtk_signal_name                        (guint          signal_id);
const gchar *gtk_text_buffer_get_clipboard_contents (GtkTextBuffer *buffer);
gchar*       gtk_widget_get_name                    (GtkWidget     *widget);

gchar* g_getenv         (const gchar *variable);
gchar* g_strerror       (gint         errnum);
gchar* g_strsignal      (gint         signum);
gchar* g_get_user_name  (void);
gchar* g_get_real_name  (void);
gchar* g_get_home_dir   (void);
gchar* g_get_tmp_dir    (void);
gchar* g_get_prgname    (void);
gchar* g_basename       (const gchar *file_name);
gchar* g_path_skip_root (gchar       *file_name);

gchar* g_module_error              (void);
gchar* g_module_name               (GModule      *module);
gchar* g_type_name                 (GType         type);
gchar* g_value_get_string          (GValue       *value);

Alloc
=====

gchar* gdk_atom_name          (GdkAtom       atom);
gchar *gtk_frame_get_label    (GtkFrame     *frame);
gchar *gtk_label_get_text     (GtkLabel     *label);
gchar* gtk_rc_get_theme_dir   (void);
gchar* gtk_rc_get_module_dir  (void);
char * pango_context_get_lang (PangoContext *context);
char * gtk_text_mark_get_name (GtkTextMark  *mark);
gchar* g_value_dup_string     (GValue       *value);

gchar* gtk_accelerator_name (guint             accelerator_key,
			     GdkModifierType   accelerator_mods);
gchar* gtk_args_collect     (GtkType           object_type,
			     GHashTable       *arg_info_hash_table,
			     GSList          **arg_list_p,
			     GSList          **info_list_p,
			     const gchar      *first_arg_name,
			     va_list           var_args);
gchar* gtk_arg_get_info     (GtkType           object_type,
			     GHashTable       *arg_info_hash_table,
			     const gchar      *arg_name,
			     GtkArgInfo      **info_p);
gchar* gtk_container_child_args_collect   (GtkType        object_type,
					   GSList       **arg_list_p,
					   GSList       **info_list_p,
					   const gchar   *first_arg_name,
					   va_list        args);
gchar* gtk_container_child_arg_get_info   (GtkType        object_type,
					   const gchar   *arg_name,
					   GtkArgInfo   **info_p);
gchar* gtk_container_child_composite_name (GtkContainer  *container,
					   GtkWidget     *child);
gchar* gtk_editable_get_chars (GtkEditable  *editable,
			       gint          start_pos,
			       gint          end_pos);

gchar* gtk_font_selection_get_font_name (GtkFontSelection *fontsel);
gchar*	 gtk_font_selection_dialog_get_font_name    (GtkFontSelectionDialog *fsd);

gchar* gtk_object_args_collect (GtkType       object_type,
				GSList      **arg_list_p,
				GSList      **info_list_p,
				const gchar  *first_arg_name,
				va_list       var_args);

gchar*	gtk_object_arg_get_info (GtkType      object_type,
				 const gchar *arg_name,
gchar* gtk_progress_get_current_text    (GtkProgress *progress);
gchar* gtk_progress_get_text_from_value (GtkProgress *progress,
					 gfloat       value);
gchar* gtk_rc_find_pixmap_in_path       (GScanner    *scanner,
					 const gchar *pixmap_file);
gchar* gtk_rc_find_module_in_path       (const gchar *module_file);

gchar* gtk_text_buffer_get_text       (GtkTextBuffer     *buffer,
				      const GtkTextIter *start_iter,
				      const GtkTextIter *end_iter,
				      gboolean           include_hidden_chars);
gchar* gtk_text_buffer_get_text_chars (GtkTextBuffer     *buffer,
				      gint               start_char,
				      gint               end_char,
				      gboolean           include_hidden_chars);

gchar* gtk_text_buffer_get_text_from_line (GtkTextBuffer     *buffer,
					  gint               line,
					  gint               start_char,
					  gint               end_char,
					  gboolean           include_hidden_chars);
gchar* gtk_text_buffer_get_slice          (GtkTextBuffer     *buffer,
					  const GtkTextIter *start_iter,
					  const GtkTextIter *end_iter,
					  gboolean           include_hidden_chars);

gchar* gtk_text_buffer_get_slice_chars     (GtkTextBuffer     *buffer,
					   gint               start_char,
					   gint               end_char,
					   gboolean           include_hidden_chars);
gchar* gtk_text_buffer_get_slice_from_line (GtkTextBuffer     *buffer,
					   gint               line);
char * gtk_text_iter_get_slice         (const GtkTextIter *start,
					const GtkTextIter *end);
gchar *gtk_text_iter_get_text          (const GtkTextIter *start,
					const GtkTextIter *end);
gchar *gtk_text_iter_get_visible_slice (const GtkTextIter *start,
					const GtkTextIter *end);
gchar *gtk_text_iter_get_visible_text  (const GtkTextIter *start,
					const GtkTextIter *end);
char *pango_x_make_matching_xlfd (PangoFontMap  *fontmap,
				  char          *xlfd,
				  const char    *charset,
				  int            size);
char *pango_x_font_subfont_xlfd  (PangoFont     *font,
				  PangoXSubfont  subfont_id);

gchar* g_strcompress         (const gchar  *source);
gchar* g_strescape           (const gchar  *source,
			      const gchar  *exceptions);
gchar* g_get_current_dir     (void);
gchar *g_get_codeset         (void);
gchar* g_dirname             (const gchar  *file_name);
gchar *g_win32_getlocale     (void);
gchar *g_win32_error_message (gint          error);
gchar* g_module_build_path   (const gchar  *directory,
			      const gchar  *module_name);

Obvious no-copy
===============
gchar *  g_utf8_offset_to_pointer  (const gchar *str,
				    gint         offset);
gchar *  g_utf8_prev_char         (const gchar *p);
gchar *  g_utf8_find_next_char    (const gchar *p,
				   const gchar *bound);
gchar *  g_utf8_find_prev_char    (const gchar *str,
gchar *g_utf8_strchr  (const gchar *p,
		       gunichar     ch);
gchar *g_utf8_strrchr (const gchar *p,
		       gunichar     ch);

gchar* g_string_chunk_insert       (GStringChunk *chunk,
				    const gchar  *string);
gchar* g_string_chunk_insert_const (GStringChunk *chunk,
				    const gchar  *string);

Obvious copy
============
gchar     *gdk_wcstombs         (const GdkWChar  *src);

gchar*	 g_strnfill		(guint	      length,
				 gchar	      fill_char);
gchar *g_utf8_strncpy (gchar       *dest,
		       const gchar *src,
		       size_t       n);
gchar *    g_utf16_to_utf8 (const gunichar2 *str,
			    gint             len);
gchar *    g_ucs4_to_utf8  (const gunichar  *str,
			    gint             len);
gchar*	 g_strdup		(const gchar *str);
gchar*	 g_strdup_printf	(const gchar *format,
				 ...) G_GNUC_PRINTF (1, 2);
gchar*	 g_strdup_vprintf	(const gchar *format,
				 va_list      args);
gchar*	 g_strndup		(const gchar *str,
				 guint	      n);
gchar*	 g_strconcat		(const gchar *string1,
				 ...); /* NULL terminated */
gchar*   g_strjoin		(const gchar  *separator,
				 ...); /* NULL terminated */
gchar* g_strjoinv            (const gchar  *separator,
			      gchar       **str_array);
gchar*   g_filename_to_utf8 (const gchar *opsysstring);
gchar*   g_filename_from_utf8 (const gchar *utf8string);

Modify-and-place-and-return
===========================

gchar*	 g_strdelimit		(gchar	     *string,
				 const gchar *delimiters,
				 gchar	      new_delimiter);
gchar*	 g_strcanon		(gchar       *string,
				 const gchar *valid_chars,
				 gchar        subsitutor);
gchar*	 g_strup		(gchar	     *string);
gchar* g_strdown        (gchar       *string);
gchar*	 g_strreverse		(gchar	     *string);
gchar*   g_strchug              (gchar        *string);
gchar*  g_strchomp              (gchar        *string);
#define g_strstrip( string )	g_strchomp (g_strchug (string))