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77 lines
1.9 KiB
C++
77 lines
1.9 KiB
C++
// list.h
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/**
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* Copyright (C) 2008 10gen Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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namespace mongo {
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/* this class uses a mutex for writes, but not for reads.
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we can get fancier later...
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struct MemberInfo : public List1<MemberInfo>::Base {
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const char *host;
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int port;
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};
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List1<MemberInfo> _members;
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_members.head()->next();
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*/
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template<typename T>
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class List1 : boost::noncopyable{
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public:
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/* next() and head() return 0 at end of list */
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class Base {
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friend class List1;
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T *_next;
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public:
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T* next() const { return _next; }
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};
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T* head() const { return _head; }
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void push(T* t) {
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boost::mutex::scoped_lock lk(_m);
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t->_next = _head;
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_head = t;
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}
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/* t is not deleted, but is removed from the list. (orphaned) */
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void orphan(T* t) {
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boost::mutex::scoped_lock lk(_m);
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T *&prev = _head;
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T *n = prev;
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while( n != t ) {
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prev = n->_next;
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n = prev;
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}
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prev = t->_next;
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if( ++_orphans > 500 )
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log() << "warning orphans=" << _orphans << '\n';
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}
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List1() : _head(0), _orphans(0) { }
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private:
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T *_head;
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boost::mutex _m;
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int _orphans;
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};
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};
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