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eba9c15746
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
120 lines
2.7 KiB
C++
120 lines
2.7 KiB
C++
/*
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* \brief Interface for allocating RAM dataspaces
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* \author Norman Feske
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* \date 2017-05-02
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*/
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/*
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* Copyright (C) 2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__BASE__RAM_ALLOCATOR_H_
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#define _INCLUDE__BASE__RAM_ALLOCATOR_H_
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#include <base/capability.h>
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#include <base/quota_guard.h>
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#include <base/cache.h>
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#include <dataspace/dataspace.h>
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namespace Genode {
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struct Ram_dataspace : Dataspace { };
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typedef Capability<Ram_dataspace> Ram_dataspace_capability;
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struct Ram_allocator;
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class Constrained_ram_allocator;
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}
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struct Genode::Ram_allocator : Interface
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{
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/**
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* Allocate RAM dataspace
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*
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* \param size size of RAM dataspace
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* \param cached selects cacheability attributes of the memory,
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* uncached memory, i.e., for DMA buffers
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*
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* \throw Out_of_ram
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* \throw Out_of_caps
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*
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* \return capability to new RAM dataspace
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*/
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virtual Ram_dataspace_capability alloc(size_t size,
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Cache_attribute cached = CACHED) = 0;
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/**
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* Free RAM dataspace
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*
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* \param ds dataspace capability as returned by alloc
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*/
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virtual void free(Ram_dataspace_capability ds) = 0;
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/**
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* Return size of dataspace in bytes
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*/
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virtual size_t dataspace_size(Ram_dataspace_capability ds) const = 0;
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};
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/**
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* Quota-bounds-checking wrapper of the 'Ram_allocator' interface
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*/
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class Genode::Constrained_ram_allocator : public Ram_allocator
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{
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private:
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Ram_allocator &_ram_alloc;
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Ram_quota_guard &_ram_guard;
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Cap_quota_guard &_cap_guard;
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public:
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Constrained_ram_allocator(Ram_allocator &ram_alloc,
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Ram_quota_guard &ram_guard,
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Cap_quota_guard &cap_guard)
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:
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_ram_alloc(ram_alloc), _ram_guard(ram_guard), _cap_guard(cap_guard)
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{ }
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Ram_dataspace_capability alloc(size_t size, Cache_attribute cached) override
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{
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size_t page_aligned_size = align_addr(size, 12);
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Ram_quota_guard::Reservation ram (_ram_guard, Ram_quota{page_aligned_size});
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Cap_quota_guard::Reservation caps(_cap_guard, Cap_quota{1});
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/*
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* \throw Out_of_caps, Out_of_ram
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*/
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Ram_dataspace_capability ds = _ram_alloc.alloc(page_aligned_size, cached);
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ram. acknowledge();
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caps.acknowledge();
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return ds;
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}
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void free(Ram_dataspace_capability ds) override
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{
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size_t const size = _ram_alloc.dataspace_size(ds);
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_ram_alloc.free(ds);
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_ram_guard.replenish(Ram_quota{size});
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_cap_guard.replenish(Cap_quota{1});
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}
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size_t dataspace_size(Ram_dataspace_capability ds) const override
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{
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return _ram_alloc.dataspace_size(ds);
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}
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};
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#endif /* _INCLUDE__BASE__RAM_ALLOCATOR_H_ */
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