implement extended uci lookup syntax

[project/uci.git] / list.c

diff --git a/list.c b/list.c
index b20ee71..41cfc24 100644 (file)
--- a/list.c
+++ b/list.c
@@ -228,6 +228,115 @@ static struct uci_element *uci_lookup_list(struct uci_list *list, const char *na
        return NULL;
 }
 
+int uci_lookup_ext(struct uci_context *ctx, struct uci_element **res, char *ptr)
+{
+       struct uci_package *p = NULL;
+       struct uci_element *e;
+       struct uci_section *s;
+       char *package = NULL;
+       char *section = NULL;
+       char *option = NULL;
+       char *idxstr, *t;
+       int idx, c;
+
+       UCI_HANDLE_ERR(ctx);
+       UCI_ASSERT(ctx, res != NULL);
+       UCI_ASSERT(ctx, ptr != NULL);
+
+       UCI_INTERNAL(uci_parse_tuple, ctx, ptr, &package, &section, &option, NULL);
+
+       /* look up the package first */
+       e = uci_lookup_list(&ctx->root, package);
+       if (!e) {
+               UCI_INTERNAL(uci_load, ctx, package, &p);
+               if (!p)
+                       goto notfound;
+               e = &p->e;
+       } else {
+               p = uci_to_package(e);
+       }
+
+       if (!section)
+               goto done;
+
+       /* if the section name validates as a regular name, pass through
+        * to the regular uci_lookup function call */
+       if (!*section || uci_validate_name(section)) {
+               UCI_INTERNAL(uci_lookup, ctx, &e, p, section, option);
+               goto done;
+       }
+
+       /* name did not validate, that means we have an extended lookup call
+        * parse it here. for now only the section index syntax is supported */
+       if (section[0] != '@')
+               goto error;
+
+       section++;
+
+       /* parse the section index part */
+       idxstr = strchr(section, '[');
+       if (!idxstr)
+               goto error;
+       *idxstr = 0;
+       idxstr++;
+
+       t = strchr(idxstr, ']');
+       if (!t)
+               goto error;
+       if (t[1] != 0)
+               goto error;
+       *t = 0;
+
+       t = NULL;
+       idx = strtol(idxstr, &t, 10);
+       if (t && *t)
+               goto error;
+
+       if (!*section)
+               section = NULL;
+       if (section && !uci_validate_str(section, false))
+               goto error;
+
+       /* if the given index is negative, it specifies the section number from 
+        * the end of the list */
+       if (idx < 0) {
+               c = 0;
+               uci_foreach_element(&p->sections, e) {
+                       s = uci_to_section(e);
+                       if (section && (strcmp(s->type, section) != 0))
+                               continue;
+
+                       c++;
+               }
+               idx += c;
+       }
+
+       c = 0;
+       uci_foreach_element(&p->sections, e) {
+               s = uci_to_section(e);
+               if (section && (strcmp(s->type, section) != 0))
+                       continue;
+
+               if (idx == c)
+                       goto found;
+               c++;
+       }
+       goto notfound;
+
+found:
+       if (option)
+               e = uci_lookup_list(&s->options, option);
+done:
+       *res = e;
+       return 0;
+
+notfound:
+       UCI_THROW(ctx, UCI_ERR_NOTFOUND);
+error:
+       UCI_THROW(ctx, UCI_ERR_INVAL);
+       return 0;
+}
+
 int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *p, const char *section, const char *option)
 {
        struct uci_element *e;