Add "per-process" file caching feature

Allows chosing page caching based on process name.

src/config_set.cpp

@@ -0,0 +1,43 @@
+/*
+  ISC License
+
+  Copyright (c) 2023, Antonio SJ Musumeci <trapexit@spawn.link>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "config_set.hpp"
+
+#include "str.hpp"
+
+
+ConfigSet::ConfigSet(const std::string &str_)
+{
+  from_string(str_);
+}
+
+std::string
+ConfigSet::to_string(void) const
+{
+  return str::join(*this,'|');
+}
+
+int
+ConfigSet::from_string(const std::string &str_)
+{
+  this->clear();
+
+  str::split(str_,'|',this);
+
+  return 0;
+}