Preserve URL sorting arguments on directory links

If a sorting criteria different than the default is used, carry the URL
arguments to the links pointing to other directories, so the sorting is
"remembered" when navigating across different directories.

ngx_http_fancyindex_module.c

@@ -375,7 +375,7 @@ make_content_buf(
     ngx_http_fancyindex_entry_t *entry;
 
     int (*sort_cmp_func) (const void*, const void*);
-    ngx_int_t    sort_descending = 0;
+    const char  *sort_url_args = "";
 
     off_t        length;
     size_t       len, root, copy, allocated;
@@ -559,6 +559,7 @@ make_content_buf(
     len = r->uri.len
         + ngx_sizeof_ssz(t05_body2)
         + ngx_sizeof_ssz(t06_list1)
+        + ngx_sizeof_ssz(t_parentdir_entry)
         + ngx_sizeof_ssz(t07_list2)
         ;
 
@@ -569,12 +570,13 @@ make_content_buf(
          * is stripped out:
          *
          *   <tr class="X">
-         *     <td><a href="U">fname</a></td>
+         *     <td><a href="U[?sort]">fname</a></td>
          *     <td>size</td><td>date</td>
          *   </tr>
          */
         len += ngx_sizeof_ssz("<tr class=\"X\"><td><a href=\"")
             + entry[i].name.len + entry[i].escape /* Escaped URL */
+            + ngx_sizeof_ssz("?C=x&amp;O=y") /* URL sorting arguments */
             + ngx_sizeof_ssz("\">")
             + entry[i].name.len + entry[i].utf_len
             + NGX_HTTP_FANCYINDEX_NAME_LEN + ngx_sizeof_ssz("&gt;")
@@ -590,8 +592,6 @@ make_content_buf(
     if ((b = ngx_create_temp_buf(r->pool, len)) == NULL)
         return NGX_HTTP_INTERNAL_SERVER_ERROR;
 
-    /* Sort entries, if needed */
-    if (entries.nelts > 1) {
     /*
      * Determine the sorting criteria. URL arguments look like:
      *
@@ -603,7 +603,7 @@ make_content_buf(
         r->args.data[0] == 'C' && r->args.data[1] == '=')
     {
         /* Determine whether the direction of the sorting */
-            sort_descending = r->args.len == 7
+        ngx_int_t sort_descending = r->args.len == 7
                                  && r->args.data[4] == 'O'
                                  && r->args.data[5] == '='
                                  && r->args.data[6] == 'D';
@@ -611,20 +611,34 @@ make_content_buf(
         /* Pick the sorting criteria */
         switch (r->args.data[2]) {
             case 'M': /* Sort by mtime */
-                    sort_cmp_func = sort_descending
+                if (sort_descending) {
-                        ? ngx_http_fancyindex_cmp_entries_mtime_desc
+                    sort_cmp_func = ngx_http_fancyindex_cmp_entries_mtime_desc;
-                        : ngx_http_fancyindex_cmp_entries_mtime_asc;
+                    sort_url_args = "?C=M&amp;O=D";
+                }
+                else {
+                    sort_cmp_func = ngx_http_fancyindex_cmp_entries_mtime_asc;
+                    sort_url_args = "?C=M&amp;O=A";
+                }
                 break;
             case 'S': /* Sort by size */
-                    sort_cmp_func = sort_descending
+                if (sort_descending) {
-                        ? ngx_http_fancyindex_cmp_entries_size_desc
+                    sort_cmp_func = ngx_http_fancyindex_cmp_entries_size_desc;
-                        : ngx_http_fancyindex_cmp_entries_size_asc;
+                    sort_url_args = "?C=S&amp;O=D";
+                }
+                else {
+                    sort_cmp_func = ngx_http_fancyindex_cmp_entries_size_asc;
+                    sort_url_args = "?C=S&amp;O=A";
+                }
                 break;
             case 'N': /* Sort by name */
             default:
-                    sort_cmp_func = sort_descending
+                if (sort_descending) {
-                        ? ngx_http_fancyindex_cmp_entries_name_desc
+                    sort_cmp_func = ngx_http_fancyindex_cmp_entries_name_desc;
-                        : ngx_http_fancyindex_cmp_entries_name_asc;
+                    sort_url_args = "?C=N&amp;O=D";
+                }
+                else {
+                    sort_cmp_func = ngx_http_fancyindex_cmp_entries_name_asc;
+                }
                 break;
         }
     }
@@ -632,6 +646,8 @@ make_content_buf(
         sort_cmp_func = ngx_http_fancyindex_cmp_entries_name_asc;
     }
 
+    /* Sort entries, if needed */
+    if (entries.nelts > 1) {
         ngx_qsort(entry, (size_t) entries.nelts,
                   sizeof(ngx_http_fancyindex_entry_t),
                   sort_cmp_func);
@@ -643,6 +659,22 @@ make_content_buf(
 
     tp = ngx_timeofday();
 
+    /* "Parent dir" entry, always first */
+    b->last = ngx_cpymem_ssz(b->last,
+                             "<tr class=\"o\">"
+                             "<td><a href=\"../");
+    if (*sort_url_args) {
+        b->last = ngx_cpymem(b->last,
+                             sort_url_args,
+                             ngx_sizeof_ssz("?C=N&amp;O=A"));
+    }
+    b->last = ngx_cpymem_ssz(b->last,
+                             "\">Parent directory/</a></td>"
+                             "<td>-</td>"
+                             "<td>-</td>"
+                             "</tr>");
+
+    /* Entries for directories and files */
     for (i = 0; i < entries.nelts; i++) {
         static const char _evenodd[] = { 'e', 'o' };
         b->last = ngx_cpymem_ssz(b->last, "<tr class=\"");
@@ -666,6 +698,11 @@ make_content_buf(
 
         if (entry[i].dir) {
             *b->last++ = '/';
+            if (*sort_url_args) {
+                b->last = ngx_cpymem(b->last,
+                                     sort_url_args,
+                                     ngx_sizeof_ssz("?C=x&amp;O=y"));
+            }
         }
 
         *b->last++ = '"';

template.h

@@ -72,8 +72,10 @@ static const u_char t06_list1[] = ""
 "</thead>"
 "\n"
 "<tbody>"
+;
+static const u_char t_parentdir_entry[] = ""
 "<tr class=\"o\">"
-"<td><a href=\"../\">Parent directory/</a></td>"
+"<td><a href=\"../?C=N&amp;O=A\">Parent directory/</a></td>"
 "<td>-</td>"
 "<td>-</td>"
 "</tr>"
@@ -93,6 +95,7 @@ static const u_char t08_foot1[] = ""
 	+ nfi_sizeof_ssz(t04_body1) \
 	+ nfi_sizeof_ssz(t05_body2) \
 	+ nfi_sizeof_ssz(t06_list1) \
+	+ nfi_sizeof_ssz(t_parentdir_entry) \
 	+ nfi_sizeof_ssz(t07_list2) \
 	+ nfi_sizeof_ssz(t08_foot1) \
 	)

template.html

@@ -70,8 +70,9 @@
 			</thead>
 
 			<tbody>
+<!-- var t_parentdir_entry -->
 				<tr class="o">
-					<td><a href="../">Parent directory/</a></td>
+					<td><a href="../?C=N&amp;O=A">Parent directory/</a></td>
 					<td>-</td>
 					<td>-</td>
 				</tr>