6b289a1423
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
111 lines
2.7 KiB
C++
111 lines
2.7 KiB
C++
/*
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* \brief Mechanism to deliver signals via core
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* \author Norman Feske
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* \date 2016-01-04
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*/
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/*
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* Copyright (C) 2016-2017 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 _CORE__INCLUDE__SIGNAL_BROKER_H_
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#define _CORE__INCLUDE__SIGNAL_BROKER_H_
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#include <signal_source_component.h>
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#include <signal_source/capability.h>
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#include <signal_context_slab.h>
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#include <signal_delivery_proxy.h>
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namespace Genode { class Signal_broker; }
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class Genode::Signal_broker
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{
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private:
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Allocator &_md_alloc;
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Rpc_entrypoint &_source_ep;
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Rpc_entrypoint &_context_ep;
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Signal_source_component _source;
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Signal_source_capability _source_cap;
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Signal_context_slab _contexts_slab { _md_alloc };
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Signal_delivery_proxy_component _delivery_proxy { _source_ep };
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public:
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class Invalid_signal_source : public Exception { };
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Signal_broker(Allocator &md_alloc,
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Rpc_entrypoint &source_ep,
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Rpc_entrypoint &context_ep)
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:
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_md_alloc(md_alloc),
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_source_ep(source_ep),
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_context_ep(context_ep),
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_source(_context_ep),
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_source_cap(_source_ep.manage(&_source))
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{ }
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~Signal_broker()
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{
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/* remove source from entrypoint */
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_source_ep.dissolve(&_source);
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/* free all signal contexts */
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while (Signal_context_component *r = _contexts_slab.any_signal_context())
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free_context(r->cap());
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}
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Signal_source_capability alloc_signal_source() { return _source_cap; }
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void free_signal_source(Signal_source_capability) { }
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Signal_context_capability
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alloc_context(Signal_source_capability, unsigned long imprint)
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{
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/*
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* XXX For now, we ignore the signal-source argument as we
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* create only a single receiver for each PD.
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*/
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Signal_context_component &context = *new (&_contexts_slab)
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Signal_context_component(imprint, _source);
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return _context_ep.manage(&context);
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}
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void free_context(Signal_context_capability context_cap)
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{
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Signal_context_component *context = nullptr;
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_context_ep.apply(context_cap, [&] (Signal_context_component *c) {
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if (!c) {
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warning("specified signal-context capability has wrong type");
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return;
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}
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context = c;
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_context_ep.dissolve(context);
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});
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if (!context)
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return;
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/* release solely in context of context_ep thread */
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if (context->enqueued() && !_context_ep.is_myself())
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_delivery_proxy.release(*context);
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destroy(&_contexts_slab, context);
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}
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void submit(Signal_context_capability const cap, unsigned const cnt)
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{
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_delivery_proxy.submit(cap, cnt);
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}
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};
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#endif /* _CORE__INCLUDE__SIGNAL_BROKER_H_ */
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