Optimization of history saving.

Now history is not saved if it was not modified and content of input
line is equal to history top entry. Thanks Francesco Cosoleto
<cosoleto at gmail dot com> for the original patch.

Also fixed a regression introduced in cff59255982d470b11a97408d7d3571b03b8401a:
after CK_HistoryNext and CK_HistoryPrev actions in input line,
the input line content is not put to the top of history.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

lib/widget/input.c

@@ -83,6 +83,19 @@ static char *kill_buffer = NULL;
 /*** file scope functions ************************************************************************/
 /* --------------------------------------------------------------------------------------------- */
 
+static size_t
+get_history_length (const GList *history)
+{
+    size_t len = 0;
+
+    for (; history != NULL; history = g_list_previous (history))
+        len++;
+
+    return len;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
 static void
 draw_history_button (WInput * in)
 {
@@ -170,14 +183,21 @@ delete_region (WInput * in, int x_first, int x_last)
 static void
 do_show_hist (WInput * in)
 {
+    size_t len;
     char *r;
 
+    len = get_history_length (in->history);
+
     r = history_show (&in->history, &in->widget);
     if (r != NULL)
     {
         input_assign_text (in, r);
         g_free (r);
     }
+
+    /* Has history cleaned up or not? */
+    if (len != get_history_length (in->history))
+        in->history_changed = TRUE;
 }
 
 /* --------------------------------------------------------------------------------------------- */
@@ -224,7 +244,13 @@ push_history (WInput * in, const char *text)
         strip_password (t, i >= ELEMENTS);
     }
 
-    in->history = list_append_unique (in->history, t);
+    if (in->history == NULL || in->history->data == NULL || strcmp (in->history->data, t) != 0 ||
+        in->history_changed)
+    {
+        in->history = list_append_unique (in->history, t);
+        in->history_changed = TRUE;
+    }
+
     in->need_push = FALSE;
 }
 
@@ -584,6 +610,7 @@ hist_prev (WInput * in)
     if (prev != NULL)
     {
         in->history = prev;
+        in->history_changed = TRUE;
         input_assign_text (in, (char *) prev->data);
         in->need_push = FALSE;
     }
@@ -612,6 +639,7 @@ hist_next (WInput * in)
     else
     {
         in->history = next;
+        in->history_changed = TRUE;
         input_assign_text (in, (char *) next->data);
         in->need_push = FALSE;
     }
@@ -814,13 +842,14 @@ input_save_history (const gchar * event_group_name, const gchar * event_name,
     (void) event_group_name;
     (void) event_name;
 
-    if (in->history != NULL && !in->is_password && (((Widget *) in)->owner->ret_value != B_CANCEL))
+    if (in->history != NULL && in->history_changed && !in->is_password &&
+        (((Widget *) in)->owner->ret_value != B_CANCEL))
     {
         ev_history_load_save_t *ev = (ev_history_load_save_t *) data;
 
-        if (in->need_push)
-            push_history (in, in->buffer);
+        push_history (in, in->buffer);
         history_save (ev->cfg, in->history_name, in->history);
+        in->history_changed = FALSE;
     }
 
     return TRUE;
@@ -942,8 +971,9 @@ input_new (int y, int x, const int *input_colors, int width, const char *def_tex
     in->completion_flags = completion_flags;
 
     /* prepare to history setup */
-    in->history_name = NULL;
     in->history = NULL;
+    in->history_changed = FALSE;
+    in->history_name = NULL;
     if ((histname != NULL) && (*histname != '\0'))
         in->history_name = g_strdup (histname);
 
@@ -1276,12 +1306,15 @@ input_disable_update (WInput * in)
 
 /* --------------------------------------------------------------------------------------------- */
 
-/* Cleans the input line and adds the current text to the history */
+/**
+  *  Cleans the input line and adds the current text to the history
+  *
+  *  @param in the input line
+  */
 void
 input_clean (WInput * in)
 {
-    if (in->need_push)
-        push_history (in, in->buffer);
+    push_history (in, in->buffer);
     in->need_push = TRUE;
     in->buffer[0] = '\0';
     in->point = 0;

lib/widget/input.h

@@ -60,6 +60,7 @@ typedef struct
     char *buffer;               /* pointer to editing buffer */
     char *history_name;         /* name of history for loading and saving */
     GList *history;             /* the history */
+    gboolean history_changed;   /* the history has changed */
     gboolean need_push;         /* need to push the current Input on hist? */
     char **completions;         /* possible completions array */
     input_complete_t completion_flags;