Implement config_item_get()

common.c

@@ -488,6 +488,18 @@ toupper_ascii (int c)
 	return c >= 'A' && c <= 'Z' ? c : c - ('a' - 'A');
 }
 
+static void
+split_str (const char *s, char delimiter, struct str_vector *out)
+{
+	const char *begin = s, *end;
+	while ((end = strchr (begin, delimiter)))
+	{
+		str_vector_add_owned (out, xstrndup (begin, end - begin));
+		begin = ++end;
+	}
+	str_vector_add (out, begin);
+}
+
 // --- Advanced configuration --------------------------------------------------
 
 // This is a new configuration format, superseding the one currently present
@@ -718,10 +730,33 @@ config_item_set_from (struct config_item_ *self, struct config_item_ *source,
 }
 
 static struct config_item_ *
-config_item_get (struct config_item_ *self, const char *path)
+config_item_get (struct config_item_ *self, const char *path, struct error **e)
 {
 	hard_assert (self->type == CONFIG_ITEM_OBJECT);
-	// TODO
+
+	struct str_vector v;
+	str_vector_init (&v);
+	split_str (path, '.', &v);
+
+	struct config_item_ *result = NULL;
+	size_t i = 0;
+	while (true)
+	{
+		const char *key = v.vector[i];
+		if (!*key)
+			error_set (e, "empty path element");
+		else if (!(self = str_map_find (&self->value.object, key)))
+			error_set (e, "`%s' not found in object", key);
+		else if (++i == v.len)
+			result = self;
+		else if (self->type != CONFIG_ITEM_OBJECT)
+			error_set (e, "`%s' is not an object", key);
+		else
+			continue;
+		break;
+	}
+	str_vector_free (&v);
+	return result;
 }
 
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