Add a read-only option

We don't save any configuration nor items if this is set. This should be
used with care, and hence there's no short option for this.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

doc/calcurse.1.txt

@@ -128,6 +128,12 @@ the *-c* flag.
   Print events and appointments for the 'num' number of days and exit. If no
   'num' is given, a range of 1 day is considered.
 
+*--read-only*::
+  Don't save configuration nor appointments/todos.
++
+'Warning:' Use this this with care! If you run an interactive calcurse instance
+in read-only mode, all changes from this session will be lost without warning!
+
 *-s*[date], *--startday*[=date]::
   Print  events  and appointments from 'date' and exit.  If no 'date' is given,
   the current day is considered.

doc/manual.txt

@@ -234,6 +234,12 @@ the `-c` flag.
   Print events and appointments for the num number of days and exit. If no num
   is given, a range of 1 day is considered.
 
+`--read-only`::
+  Don't save configuration nor appointments/todos.
++
+WARNING: Use this this with care! If you run an interactive calcurse instance
+in read-only mode, all changes from this session will be lost without warning!
+
 `-s[date], --startday[=date]`::
   Print  events  and appointments from date and exit.  If no date is given, the
   current day is considered.

src/args.c

@@ -51,7 +51,8 @@ enum {
   OPT_FMT_RAPT,
   OPT_FMT_EV,
   OPT_FMT_REV,
-  OPT_FMT_TODO
+  OPT_FMT_TODO,
+  OPT_READ_ONLY
 };
 
 /*
@@ -665,6 +666,7 @@ parse_args (int argc, char **argv)
     {"format-event", required_argument, NULL, OPT_FMT_EV},
     {"format-recur-event", required_argument, NULL, OPT_FMT_REV},
     {"format-todo", required_argument, NULL, OPT_FMT_TODO},
+    {"read-only", no_argument, NULL, OPT_READ_ONLY},
     {NULL, no_argument, NULL, 0}
   };
 
@@ -793,6 +795,9 @@ parse_args (int argc, char **argv)
         case OPT_FMT_TODO:
           fmt_todo = optarg;
           break;
+        case OPT_READ_ONLY:
+          read_only = 1;
+          break;
         default:
           usage ();
           usage_try ();

src/calcurse.h

@@ -946,6 +946,7 @@ extern int               resize;
 extern unsigned          colorize;
 extern int               foreground, background;
 extern enum ui_mode      ui_mode;
+extern int               read_only;
 extern int               days[12];
 extern char             *monthnames[12];
 extern char             *daynames[8];

src/config.c

@@ -451,19 +451,11 @@ config_file_walk (config_fn_walk_cb_t fn_cb,
                   config_fn_walk_junk_cb_t fn_junk_cb, void *data)
 {
   FILE *data_file;
-  char *mesg_line1 = _("Failed to open config file");
-  char *mesg_line2 = _("Press [ENTER] to continue");
   char buf[BUFSIZ], e_conf[BUFSIZ];
   char *key, *value;
 
   data_file = fopen (path_conf, "r");
-  if (data_file == NULL)
-    {
-      status_mesg (mesg_line1, mesg_line2);
-      wnoutrefresh (win[STA].p);
-      wins_doupdate ();
-      keys_getch (win[STA].p, NULL);
-    }
+  EXIT_IF (data_file == NULL, _("failed to open configuration file"));
 
   pthread_mutex_lock (&nbar.mutex);
   for (;;)
@@ -561,6 +553,9 @@ config_save (void)
   struct config_save_status status;
   int i;
 
+  if (read_only)
+    return 1;
+
   strncpy (tmppath, get_tempdir (), BUFSIZ);
   strncat (tmppath, "/" CONF_PATH_NAME ".", BUFSIZ - strlen (tmppath) - 1);
   if ((tmpext = new_tempfile (tmppath, TMPEXTSIZ)) == NULL)

src/io.c

@@ -355,6 +355,9 @@ io_save_apts (void)
   llist_item_t *i;
   FILE *fp;
 
+  if (read_only)
+    return 1;
+
   if ((fp = fopen (path_apts, "w")) == NULL)
     return 0;
 
@@ -387,6 +390,9 @@ io_save_todo (void)
   llist_item_t *i;
   FILE *fp;
 
+  if (read_only)
+    return 1;
+
   if ((fp = fopen (path_todo, "w")) == NULL)
     return 0;
 
@@ -406,6 +412,9 @@ io_save_keys (void)
 {
   FILE *fp;
 
+  if (read_only)
+    return 1;
+
   if ((fp = fopen (path_keys, "w")) == NULL)
     return 0;
 
@@ -424,6 +433,9 @@ io_save_cal (enum save_display display)
   char *enter = _("Press [ENTER] to continue");
   int show_bar;
 
+  if (read_only)
+    return;
+
   pthread_mutex_lock (&io_save_mutex);
 
   show_bar = 0;
@@ -487,6 +499,8 @@ io_load_app (void)
   start = end = until = *lt;
 
   data_file = fopen (path_apts, "r");
+  EXIT_IF (data_file == NULL, _("failed to open appointment file"));
+
   for (;;)
     {
       LLIST_INIT (&exc);
@@ -659,19 +673,14 @@ void
 io_load_todo (void)
 {
   FILE *data_file;
-  char *mesg_line1 = _("Failed to open todo file");
-  char *mesg_line2 = _("Press [ENTER] to continue");
   char *newline;
   int nb_tod = 0;
   int c, id;
   char buf[BUFSIZ], e_todo[BUFSIZ], note[MAX_NOTESIZ + 1];
 
   data_file = fopen (path_todo, "r");
-  if (data_file == NULL)
-    {
-      status_mesg (mesg_line1, mesg_line2);
-      wgetch (win[STA].p);
-    }
+  EXIT_IF (data_file == NULL, _("failed to open todo file"));
+
   for (;;)
     {
       c = getc (data_file);
@@ -771,7 +780,8 @@ io_load_keys (char *pager)
     }
 
   keyfp = fopen (path_keys, "r");
-  EXIT_IF (keyfp == NULL, _("could not find any key file."));
+  EXIT_IF (keyfp == NULL, _("failed to open key file"));
+
   log = io_log_init ();
   skipped = loaded = line = 0;
   while (fgets (buf, BUFSIZ, keyfp) != NULL)
@@ -883,6 +893,9 @@ io_load_keys (char *pager)
 void
 io_check_dir (char *dir, int *missing)
 {
+  if (read_only)
+    return;
+
   errno = 0;
   if (mkdir (dir, 0700) != 0)
     {
@@ -919,6 +932,9 @@ io_file_exist (char *file)
 void
 io_check_file (char *file, int *missing)
 {
+  if (read_only)
+    return;
+
   errno = 0;
   if (!io_file_exist (file))
     {

src/vars.c

@@ -58,6 +58,9 @@ int foreground, background;
  */
 enum ui_mode ui_mode = UI_CMDLINE;
 
+/* Don't save anything if this is set. */
+int read_only = 0;
+
 /*
  * variables to store calendar names
  */