Backport --(enable|disable)-(shell|delete|refresh) from 2.x

Only remaining options missing from this C implementation are
--graph-style (sounds doable, but pretty low priority) and
--shared-column (unlikely to happen).

doc/ncdu.pod

@@ -167,22 +167,29 @@ decreased to once every 2 seconds with C<-q> or C<--slow-ui-updates>. This
 feature can be used to save bandwidth over remote connections. This option has
 no effect when C<-0> is used.
 
+=item B<--enable-shell>, B<--disable-shell>
+
+Enable or disable shell spawning from the browser. This feature is enabled by
+default when scanning a live directory and disabled when importing from file.
+
+=item B<--enable-delete>, B<--disable-delete>
+
+Enable or disable the built-in file deletion feature. This feature is enabled
+by default when scanning a live directory and disabled when importing from
+file. Explicitly disabling the deletion feature can work as a safeguard to
+prevent accidental data loss.
+
+=item B<--enable-refresh>, B<--disable-refresh>
+
+Enable or disable directory refreshing from the browser. This feature is
+enabled by default when scanning a live directory and disabled when importing
+from file.
+
 =item B<-r>
 
-Read-only mode. This will disable the built-in file deletion feature. This
-option has no effect when C<-o> is used, because there will not be a browser
-interface in that case. It has no effect when C<-f> is used, either, because
-the deletion feature is disabled in that case anyway.
-
-WARNING: This option will only prevent deletion through the file browser. It is
-still possible to spawn a shell from ncdu and delete or modify files from
-there. To disable that feature as well, pass the C<-r> option twice (see
-C<-rr>).
-
-=item B<-rr>
-
-In addition to C<-r>, this will also disable the shell spawning feature of the
-file browser.
+Read-only mode. When given once, this is an alias for C<--disable-delete>, when
+given twice it will also add C<--disable-shell>, thus ensuring that there is no
+way to modify the file system from within ncdu.
 
 =item B<--si>, B<--no-si>
 
@@ -272,6 +279,9 @@ starting with C<#> are ignored. Example configuration file:
   # Always enable extended mode
   -e
 
+  # Disable file deletion
+  --disable-delete
+
   # Exclude .git directories
   --exclude .git
 

src/browser.c

@@ -272,7 +272,7 @@ void browse_draw(void) {
   addstrc(UIC_HD, " for help");
   if(dir_import_active)
     mvaddstr(0, wincols-10, "[imported]");
-  else if(read_only)
+  else if(!can_delete)
     mvaddstr(0, wincols-11, "[read-only]");
 
   /* second line - the path */
@@ -323,7 +323,7 @@ void browse_draw(void) {
   if(message) {
     nccreate(6, 60, "Message");
     ncaddstr(2, 2, message);
-    ncaddstr(4, 34, "Press any key to continue");
+    ncaddstr(4, 33, "Press any key to continue");
   }
 
   /* draw information window */
@@ -488,8 +488,8 @@ int browse_key(int ch) {
 
     /* and other stuff */
     case 'r':
-      if(dir_import_active) {
-        message = "Directory imported from file, won't refresh.";
+      if(!can_refresh) {
+        message = "Directory refresh feature disabled.";
         break;
       }
       if(dirlist_par) {
@@ -527,14 +527,12 @@ int browse_key(int ch) {
       info_show = 0;
       break;
     case 'd':
-      if(read_only >= 1 || dir_import_active) {
-        message = read_only >= 1
-          ? "File deletion disabled in read-only mode."
-          : "File deletion not available for imported directories.";
-        break;
-      }
       if(sel == NULL || sel == dirlist_parent)
         break;
+      if(!can_delete) {
+        message = "Deletion feature disabled.";
+        break;
+      }
       info_show = 0;
       if((t = dirlist_get(1)) == sel)
         if((t = dirlist_get(-1)) == sel || t == dirlist_parent)
@@ -542,10 +540,8 @@ int browse_key(int ch) {
       delete_init(sel, t);
       break;
      case 'b':
-      if(read_only >= 2 || dir_import_active) {
-        message = read_only >= 2
-          ? "Shell feature disabled in read-only mode."
-          : "Shell feature not available for imported directories.";
+      if(!can_shell) {
+        message = "Shell feature disabled.";
         break;
       }
       shell_init();

src/global.h

@@ -95,8 +95,10 @@ struct dir_ext {
 
 /* program state */
 extern int pstate;
-/* read-only flag, 1+ = disable deletion, 2+ = also disable shell */
-extern int read_only;
+/* enabled features */
+extern int can_delete;
+extern int can_shell;
+extern int can_refresh;
 /* minimum screen update interval when calculating, in ms */
 extern long update_delay;
 /* filter directories with CACHEDIR.TAG */

src/main.c

@@ -35,7 +35,9 @@
 
 
 int pstate;
-int read_only = 0;
+int can_delete = -1;
+int can_shell = -1;
+int can_refresh = -1;
 long update_delay = 100;
 int cachedir_tags = 0;
 int extended_info = 0;
@@ -197,7 +199,14 @@ static int arg_option(void) {
   else if(OPT("--cross-file-system")) dir_scan_smfs = 0;
   else if(OPT("-e") || OPT("--extended")) extended_info = 1;
   else if(OPT("--no-extended")) extended_info = 0;
-  else if(OPT("-r")) read_only++;
+  else if(OPT("-r") && !can_delete) can_shell = 0;
+  else if(OPT("-r")) can_delete = 0;
+  else if(OPT("--enable-shell")) can_shell = 1;
+  else if(OPT("--disable-shell")) can_shell = 0;
+  else if(OPT("--enable-delete")) can_delete = 1;
+  else if(OPT("--disable-delete")) can_delete = 0;
+  else if(OPT("--enable-refresh")) can_refresh = 1;
+  else if(OPT("--disable-refresh")) can_refresh = 0;
   else if(OPT("--show-hidden")) dirlist_hidden = 0;
   else if(OPT("--hide-hidden")) dirlist_hidden = 1;
   else if(OPT("--show-itemcount")) show_items = 1;
@@ -406,6 +415,10 @@ static void argv_parse(int argc, char **argv) {
    * feedback when exporting to stdout. */
   if(dir_ui == -1)
     dir_ui = export && strcmp(export, "-") == 0 ? 0 : export ? 1 : 2;
+
+  if(can_delete == -1)  can_delete  = import ? 0 : 1;
+  if(can_shell == -1)   can_shell   = import ? 0 : 1;
+  if(can_refresh == -1) can_refresh = import ? 0 : 1;
 }