genode/repos/os/src/server/input_filter/source.h
Norman Feske eba9c15746 Follow practices suggested by "Effective C++"
The patch adjust the code of the base, base-<kernel>, and os repository.
To adapt existing components to fix violations of the best practices
suggested by "Effective C++" as reported by the -Weffc++ compiler
argument. The changes follow the patterns outlined below:

* A class with virtual functions can no longer publicly inherit base
  classed without a vtable. The inherited object may either be moved
  to a member variable, or inherited privately. The latter would be
  used for classes that inherit 'List::Element' or 'Avl_node'. In order
  to enable the 'List' and 'Avl_tree' to access the meta data, the
  'List' must become a friend.

* Instead of adding a virtual destructor to abstract base classes,
  we inherit the new 'Interface' class, which contains a virtual
  destructor. This way, single-line abstract base classes can stay
  as compact as they are now. The 'Interface' utility resides in
  base/include/util/interface.h.

* With the new warnings enabled, all member variables must be explicitly
  initialized. Basic types may be initialized with '='. All other types
  are initialized with braces '{ ... }' or as class initializers. If
  basic types and non-basic types appear in a row, it is nice to only
  use the brace syntax (also for basic types) and align the braces.

* If a class contains pointers as members, it must now also provide a
  copy constructor and assignment operator. In the most cases, one
  would make them private, effectively disallowing the objects to be
  copied. Unfortunately, this warning cannot be fixed be inheriting
  our existing 'Noncopyable' class (the compiler fails to detect that
  the inheriting class cannot be copied and still gives the error).
  For now, we have to manually add declarations for both the copy
  constructor and assignment operator as private class members. Those
  declarations should be prepended with a comment like this:

        /*
         * Noncopyable
         */
        Thread(Thread const &);
        Thread &operator = (Thread const &);

  In the future, we should revisit these places and try to replace
  the pointers with references. In the presence of at least one
  reference member, the compiler would no longer implicitly generate
  a copy constructor. So we could remove the manual declaration.

Issue #465
2018-01-17 12:14:35 +01:00

101 lines
1.9 KiB
C++

/*
* \brief Input-event source interface
* \author Norman Feske
* \date 2017-02-01
*/
/*
* Copyright (C) 2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INPUT_FILTER__SOURCE_H_
#define _INPUT_FILTER__SOURCE_H_
/* Genode includes */
#include <base/registry.h>
#include <input/event.h>
/* local includes */
#include <types.h>
namespace Input_filter { struct Source; }
class Input_filter::Source
{
private:
Registry<Source>::Element _owner_elem;
public:
struct Invalid_config : Exception { };
Source(Registry<Source> &owner) : _owner_elem(owner, *this) { }
virtual ~Source() { }
static bool input_node(Xml_node node)
{
return node.type() == "input"
|| node.type() == "remap"
|| node.type() == "chargen"
|| node.type() == "merge"
|| node.type() == "button-scroll"
|| node.type() == "accelerate";
return false;
}
static Xml_node input_sub_node(Xml_node node)
{
Xml_node result("<none/>");
node.for_each_sub_node([&] (Xml_node sub_node) {
if (input_node(sub_node))
result = sub_node; });
if (result.type() != "none")
return result;
warning("missing input-source sub node in ", node);
throw Invalid_config { };
}
virtual void generate() = 0;
struct Owner;
struct Sink : Interface
{
virtual void submit_event(Input::Event const &) = 0;
};
struct Factory : Interface
{
/*
* \throw Invalid_config
*/
virtual Source &create_source(Owner &, Xml_node, Sink &) = 0;
virtual void destroy_source(Source &) = 0;
};
struct Owner : Registry<Source>
{
Factory &_factory;
Owner(Factory &factory) : _factory(factory) { }
~Owner()
{
for_each([&] (Source &s) { _factory.destroy_source(s); });
}
};
};
#endif /* _INPUT_FILTER__SOURCE_H_ */