menuconfig: Add "breadcrumbs" navigation aid

Displays a trail of the menu entries used to get to the current menu.

Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
[yann.morin.1998@free.fr: small, trivial code re-ordering]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

4 files changed, 147 insertions, 3 deletions

diff --git a/scripts/kconfig/list.h b/scripts/kconfig/list.h
index b87206cc92f4..ea1d58119d20 100644
--- a/scripts/kconfig/list.h
+++ b/scripts/kconfig/list.h
@@ -101,4 +101,31 @@ static inline void list_add_tail(struct list_head *_new, struct list_head *head)
         __list_add(_new, head->prev, head);
 }
 
+/*
+ * Delete a list entry by making the prev/next entries
+ * point to each other.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_del(struct list_head *prev, struct list_head *next)
+{
+        next->prev = prev;
+        prev->next = next;
+}
+
+#define LIST_POISON1  ((void *) 0x00100100)
+#define LIST_POISON2  ((void *) 0x00200200)
+/**
+ * list_del - deletes entry from list.
+ * @entry: the element to delete from the list.
+ * Note: list_empty() on entry does not return true after this, the entry is
+ * in an undefined state.
+ */
+static inline void list_del(struct list_head *entry)
+{
+        __list_del(entry->prev, entry->next);
+        entry->next = LIST_POISON1;
+        entry->prev = LIST_POISON2;
+}
 #endif
diff --git a/scripts/kconfig/lxdialog/dialog.h b/scripts/kconfig/lxdialog/dialog.h
index 307022a8beef..1099337079b6 100644
--- a/scripts/kconfig/lxdialog/dialog.h
+++ b/scripts/kconfig/lxdialog/dialog.h
@@ -106,8 +106,14 @@ struct dialog_color {
         int hl;         /* highlight this item */
 };
 
+struct subtitle_list {
+        struct subtitle_list *next;
+        const char *text;
+};
+
 struct dialog_info {
         const char *backtitle;
+        struct subtitle_list *subtitles;
         struct dialog_color screen;
         struct dialog_color shadow;
         struct dialog_color dialog;
@@ -196,6 +202,7 @@ int on_key_resize(void);
 
 int init_dialog(const char *backtitle);
 void set_dialog_backtitle(const char *backtitle);
+void set_dialog_subtitles(struct subtitle_list *subtitles);
 void end_dialog(int x, int y);
 void attr_clear(WINDOW * win, int height, int width, chtype attr);
 void dialog_clear(void);
diff --git a/scripts/kconfig/lxdialog/util.c b/scripts/kconfig/lxdialog/util.c
index 109d53117d22..a0e97c299410 100644
--- a/scripts/kconfig/lxdialog/util.c
+++ b/scripts/kconfig/lxdialog/util.c
@@ -257,12 +257,48 @@ void dialog_clear(void)
         attr_clear(stdscr, LINES, COLS, dlg.screen.atr);
         /* Display background title if it exists ... - SLH */
         if (dlg.backtitle != NULL) {
-                int i;
+                int i, len = 0, skip = 0;
+                struct subtitle_list *pos;
 
                 wattrset(stdscr, dlg.screen.atr);
                 mvwaddstr(stdscr, 0, 1, (char *)dlg.backtitle);
+
+                for (pos = dlg.subtitles; pos != NULL; pos = pos->next) {
+                        /* 3 is for the arrow and spaces */
+                        len += strlen(pos->text) + 3;
+                }
+
                 wmove(stdscr, 1, 1);
-                for (i = 1; i < COLS - 1; i++)
+                if (len > COLS - 2) {
+                        const char *ellipsis = "[...] ";
+                        waddstr(stdscr, ellipsis);
+                        skip = len - (COLS - 2 - strlen(ellipsis));
+                }
+
+                for (pos = dlg.subtitles; pos != NULL; pos = pos->next) {
+                        if (skip == 0)
+                                waddch(stdscr, ACS_RARROW);
+                        else
+                                skip--;
+
+                        if (skip == 0)
+                                waddch(stdscr, ' ');
+                        else
+                                skip--;
+
+                        if (skip < strlen(pos->text)) {
+                                waddstr(stdscr, pos->text + skip);
+                                skip = 0;
+                        } else
+                                skip -= strlen(pos->text);
+
+                        if (skip == 0)
+                                waddch(stdscr, ' ');
+                        else
+                                skip--;
+                }
+
+                for (i = len + 1; i < COLS - 1; i++)
                         waddch(stdscr, ACS_HLINE);
         }
         wnoutrefresh(stdscr);
@@ -302,6 +338,11 @@ void set_dialog_backtitle(const char *backtitle)
         dlg.backtitle = backtitle;
 }
 
+void set_dialog_subtitles(struct subtitle_list *subtitles)
+{
+        dlg.subtitles = subtitles;
+}
+
 /*
  * End using dialog functions.
  */
diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
index c5418d622a05..387dc8daf7b2 100644
--- a/scripts/kconfig/mconf.c
+++ b/scripts/kconfig/mconf.c
@@ -311,6 +311,50 @@ static void set_config_filename(const char *config_filename)
                 filename[sizeof(filename)-1] = '\0';
 }
 
+struct subtitle_part {
+        struct list_head entries;
+        const char *text;
+};
+static LIST_HEAD(trail);
+
+static struct subtitle_list *subtitles;
+static void set_subtitle(void)
+{
+        struct subtitle_part *sp;
+        struct subtitle_list *pos, *tmp;
+
+        for (pos = subtitles; pos != NULL; pos = tmp) {
+                tmp = pos->next;
+                free(pos);
+        }
+
+        subtitles = NULL;
+        list_for_each_entry(sp, &trail, entries) {
+                if (sp->text) {
+                        if (pos) {
+                                pos->next = xcalloc(sizeof(*pos), 1);
+                                pos = pos->next;
+                        } else {
+                                subtitles = pos = xcalloc(sizeof(*pos), 1);
+                        }
+                        pos->text = sp->text;
+                }
+        }
+
+        set_dialog_subtitles(subtitles);
+}
+
+static void reset_subtitle(void)
+{
+        struct subtitle_list *pos, *tmp;
+
+        for (pos = subtitles; pos != NULL; pos = tmp) {
+                tmp = pos->next;
+                free(pos);
+        }
+        subtitles = NULL;
+        set_dialog_subtitles(subtitles);
+}