Optimize updates of status bar during search.

Optimization is based on examining file size and time of the last status
update. This is synchronous and is based on assumption that relatively
small files are quickly processed even on slow hardware so if refresh
timeout expires during their processing, the delay couldn't be noticed
by human. Therefore only rather big files have to be reported
unconditionally, and others - only if there is a match in this file or
if timeout expires.

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

src/filemanager/find.c

@@ -38,6 +38,7 @@
 #include <string.h>
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 
 #include "lib/global.h"
 
@@ -66,6 +67,9 @@
 
 /*** file scope macro definitions ****************************************************************/
 
+#define MAX_REFRESH_INTERVAL (G_USEC_PER_SEC / 20)      /* 50 ms */
+#define MIN_REFRESH_FILE_SIZE (256 * 1024)      /* 256 KB */
+
 /*** file scope type declarations ****************************************************************/
 
 /* A couple of extra messages we need */
@@ -149,6 +153,8 @@ static unsigned long matches;   /* Number of matches */
 static gboolean is_start = FALSE;       /* Status of the start/stop toggle button */
 static char *old_dir = NULL;
 
+static struct timeval last_refresh;
+
 /* Where did we stop */
 static gboolean resuming;
 static int last_line;
@@ -976,6 +982,10 @@ search_content (WDialog * h, const char *directory, const char *filename)
     int file_fd;
     gboolean ret_val = FALSE;
     vfs_path_t *vpath;
+    struct timeval tv;
+    time_t seconds;
+    suseconds_t useconds;
+    gboolean status_updated = FALSE;
 
     vpath = vfs_path_build_filename (directory, filename, (char *) NULL);
 
@@ -991,10 +1001,29 @@ search_content (WDialog * h, const char *directory, const char *filename)
     if (file_fd == -1)
         return FALSE;
 
-    g_snprintf (buffer, sizeof (buffer), _("Grepping in %s"), filename);
-    status_update (str_trunc (buffer, WIDGET (h)->cols - 8));
+    /* get time elapsed from last refresh */
+    if (gettimeofday (&tv, NULL) == -1)
+    {
+        tv.tv_sec = 0;
+        tv.tv_usec = 0;
+        last_refresh = tv;
+    }
+    seconds = tv.tv_sec - last_refresh.tv_sec;
+    useconds = tv.tv_usec - last_refresh.tv_usec;
+    if (useconds < 0)
+    {
+        seconds--;
+        useconds += G_USEC_PER_SEC;
+    }
 
-    mc_refresh ();
+    if (s.st_size >= MIN_REFRESH_FILE_SIZE || seconds > 0 || useconds > MAX_REFRESH_INTERVAL)
+    {
+        g_snprintf (buffer, sizeof (buffer), _("Grepping in %s"), filename);
+        status_update (str_trunc (buffer, WIDGET (h)->cols - 8));
+        mc_refresh ();
+        last_refresh = tv;
+        status_updated = TRUE;
+    }
 
     tty_enable_interrupt_key ();
     tty_got_interrupt ();
@@ -1069,6 +1098,17 @@ search_content (WDialog * h, const char *directory, const char *filename)
             if (!found          /* Search in binary line once */
                 && mc_search_run (search_content_handle, (const void *) strbuf, 0, i, &found_len))
             {
+                if (!status_updated)
+                {
+                    /* if we add results for a file, we have to ensure that
+                       name of this file is shown in status bar */
+                    g_snprintf (result, sizeof (result), _("Grepping in %s"), filename);
+                    status_update (str_trunc (result, WIDGET (h)->cols - 8));
+                    mc_refresh ();
+                    last_refresh = tv;
+                    status_updated = TRUE;
+                }
+
                 g_snprintf (result, sizeof (result), "%d:%s", line, filename);
                 find_add_match (directory, result);
                 found = TRUE;
@@ -1809,6 +1849,9 @@ find_file (void)
         if (pattern[0] == '\0')
             break;              /* nothing search */
 
+        last_refresh.tv_sec = 0;
+        last_refresh.tv_usec = 0;
+
         dirname = filename = NULL;
         is_start = FALSE;
         v = do_find (start_dir, start_dir_len, ignore_dirs, pattern, content, &dirname, &filename);