123 lines
2.9 KiB
C++
123 lines
2.9 KiB
C++
/*
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* \brief Connection to a service
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* \author Norman Feske
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* \date 2008-08-22
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*/
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/*
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* Copyright (C) 2008-2013 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 General Public License version 2.
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*/
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#ifndef _INCLUDE__BASE__CONNECTION_H_
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#define _INCLUDE__BASE__CONNECTION_H_
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#include <base/env.h>
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#include <base/capability.h>
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namespace Genode { template <typename> class Connection; }
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/**
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* Representation of an open connection to a service
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*/
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template <typename SESSION_TYPE>
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class Genode::Connection : public Noncopyable
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{
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public:
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enum On_destruction { CLOSE = false, KEEP_OPEN = true };
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private:
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/*
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* Because the argument string is used with the parent interface,
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* the message-buffer size of the parent-interface provides a
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* realistic upper bound for dimensioning the format- string
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* buffer.
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*/
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enum { FORMAT_STRING_SIZE = Parent::Session_args::MAX_SIZE };
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Capability<SESSION_TYPE> _cap;
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On_destruction _on_destruction;
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Capability<SESSION_TYPE> _session(Affinity const &affinity,
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const char *format_args, va_list list)
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{
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char buf[FORMAT_STRING_SIZE];
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String_console sc(buf, FORMAT_STRING_SIZE);
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sc.vprintf(format_args, list);
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va_end(list);
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/* call parent interface with the resulting argument buffer */
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return env()->parent()->session<SESSION_TYPE>(buf, affinity);
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}
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public:
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/**
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* Constructor
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*
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* \param cap session capability
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* \param od session policy applied when destructing the connection
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*
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* The 'op' argument defines whether the session should automatically
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* be closed by the destructor of the connection (CLOSE), or the
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* session should stay open (KEEP_OPEN). The latter is useful in
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* situations where the creator a connection merely passes the
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* session capability of the connection to another party but never
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* invokes any of the session's RPC functions.
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*/
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Connection(Capability<SESSION_TYPE> cap, On_destruction od = CLOSE):
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_cap(cap), _on_destruction(od) { }
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/**
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* Destructor
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*/
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~Connection()
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{
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if (_on_destruction == CLOSE)
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env()->parent()->close(_cap);
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}
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/**
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* Return session capability
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*/
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Capability<SESSION_TYPE> cap() const { return _cap; }
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/**
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* Define session policy
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*/
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void on_destruction(On_destruction od) { _on_destruction = od; }
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/**
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* Shortcut for env()->parent()->session()
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*/
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Capability<SESSION_TYPE> session(const char *format_args, ...)
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{
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va_list list;
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va_start(list, format_args);
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return _session(Affinity(), format_args, list);
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}
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/**
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* Shortcut for env()->parent()->session()
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*/
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Capability<SESSION_TYPE> session(Affinity const &affinity,
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char const *format_args, ...)
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{
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va_list list;
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va_start(list, format_args);
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return _session(affinity, format_args, list);
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}
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};
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#endif /* _INCLUDE__BASE__CONNECTION_H_ */
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