genode/repos/base/src/core/spec/x86/io_port_session_component.cc
Norman Feske 6b289a1423 base/core: use references instead of pointers
This patch replaces the former prominent use of pointers by references
wherever feasible. This has the following benefits:

* The contract between caller and callee becomes more obvious. When
  passing a reference, the contract says that the argument cannot be
  a null pointer. The caller is responsible to ensure that. Therefore,
  the use of reference eliminates the need to add defensive null-pointer
  checks at the callee site, which sometimes merely exist to be on the
  safe side. The bottom line is that the code becomes easier to follow.

* Reference members must be initialized via an object initializer,
  which promotes a programming style that avoids intermediate object-
  construction states. Within core, there are still a few pointers
  as member variables left though. E.g., caused by the late association
  of 'Platform_thread' objects with their 'Platform_pd' objects.

* If no pointers are present as member variables, we don't need to
  manually provide declarations of a private copy constructor and
  an assignment operator to avoid -Weffc++ errors "class ... has
  pointer data members [-Werror=effc++]".

This patch also changes a few system bindings on NOVA and Fiasco.OC,
e.g., the return value of the global 'cap_map' accessor has become a
reference. Hence, the patch touches a few places outside of core.

Fixes #3135
2019-02-12 10:33:13 +01:00

61 lines
1.6 KiB
C++

/*
* \brief Core implementation of the IO_PORT session interface
* \author Christian Helmuth
* \date 2007-04-17
*/
/*
* Copyright (C) 2007-2017 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.
*/
/* Genode includes */
#include <util/string.h>
#include <util/arg_string.h>
#include <root/root.h>
/* core includes */
#include <io_port_session_component.h>
using namespace Genode;
/******************************
** Constructor / destructor **
******************************/
Io_port_session_component::Io_port_session_component(Range_allocator &io_port_alloc,
const char *args)
: _io_port_alloc(io_port_alloc)
{
/* parse for port properties */
unsigned base = Arg_string::find_arg(args, "io_port_base").ulong_value(0);
unsigned size = Arg_string::find_arg(args, "io_port_size").ulong_value(0);
/* allocate region (also checks out-of-bounds regions) */
switch (io_port_alloc.alloc_addr(size, base).value) {
case Range_allocator::Alloc_return::RANGE_CONFLICT:
error("I/O port ", Hex_range<uint16_t>(base, size), " not available");
throw Service_denied();
case Range_allocator::Alloc_return::OUT_OF_METADATA:
error("I/O port allocator ran out of meta data");
throw Service_denied();
case Range_allocator::Alloc_return::OK: break;
}
/* store information */
_base = base;
_size = size;
}
Io_port_session_component::~Io_port_session_component()
{
_io_port_alloc.free(reinterpret_cast<void *>(_base));
}