101 lines
2.4 KiB
C++
101 lines
2.4 KiB
C++
/*
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* \brief Session label utility class
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* \author Emery Hemingway
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* \author Norman Feske
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* \date 2016-07-01
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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 _INCLUDE__BASE__SESSION_LABEL_H_
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#define _INCLUDE__BASE__SESSION_LABEL_H_
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#include <base/snprintf.h>
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#include <util/arg_string.h>
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#include <util/string.h>
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namespace Genode { struct Session_label; }
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struct Genode::Session_label : String<160>
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{
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private:
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static char const *_separator() { return " -> "; }
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static size_t _separator_len() { return 4; }
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public:
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using String = String<capacity()>;
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using String::String;
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Session_label last_element() const
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{
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char const * const full = string();
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size_t const full_len = strlen(full);
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if (full_len < _separator_len())
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return full;
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unsigned i = full_len - _separator_len();
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do {
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if (!strcmp(_separator(), full + i, _separator_len()))
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return full + i + _separator_len();
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} while (i-- > 0);
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return Session_label(Cstring(full));
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}
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/**
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* Return part of the label without the last element
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*/
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inline Session_label prefix() const
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{
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if (length() < _separator_len() + 1)
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return Session_label();
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/* search for last occurrence of the separator */
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unsigned prefix_len = length() - _separator_len() - 1;
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char const * const full = string();
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for (; prefix_len > 0; prefix_len--)
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if (strcmp(full + prefix_len, _separator(), _separator_len()) == 0)
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break;
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/* construct new label with only the prefix part */
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return Session_label(Cstring(full, prefix_len));
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}
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};
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namespace Genode {
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/**
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* Extract label from session arguments in the form of 'label="..."'
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*/
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inline Session_label label_from_args(char const *args)
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{
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char buf[Session_label::capacity()];
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Arg_string::find_arg(args, "label").string(buf, sizeof(buf), "");
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return Session_label(Cstring(buf));
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}
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/**
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* Create a compound label in the form of 'prefix -> label'
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*/
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template <size_t N1, size_t N2>
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inline Session_label prefixed_label(String<N1> const &prefix,
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String<N2> const &label)
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{
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String<N1 + N2 + 4> const prefixed_label(prefix, " -> ", label);
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return Session_label(prefixed_label);
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}
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}
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#endif /* _INCLUDE__BASE__SESSION_LABEL_H_ */
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