--- old/agent/src/os/win32/Monitor.cpp Fri Sep 9 14:17:22 2011 +++ /dev/null Fri Sep 9 14:17:01 2011 @@ -1,176 +0,0 @@ -/* - * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved. - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. - * - * This code is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License version 2 only, as - * published by the Free Software Foundation. - * - * This code is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License - * version 2 for more details (a copy is included in the LICENSE file that - * accompanied this code). - * - * You should have received a copy of the GNU General Public License version - * 2 along with this work; if not, write to the Free Software Foundation, - * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. - * - * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA - * or visit www.oracle.com if you need additional information or have any - * questions. - * - */ - -#include -#include -#include "Monitor.hpp" - -Monitor::Monitor() { - _lock_count = -1; // No threads have entered the critical section - _owner = NULL; - _lock_event = CreateEvent(NULL, false, false, NULL); - _wait_event = CreateEvent(NULL, true, false, NULL); - _counter = 0; - _tickets = 0; - _waiters = 0; -} - -Monitor::~Monitor() { - assert(_owner == NULL); // Otherwise, owned monitor being deleted - assert(_lock_count == -1); // Otherwise, monitor being deleted with non -1 lock count - CloseHandle(_lock_event); - CloseHandle(_wait_event); -} - -void -Monitor::lock() { - if (InterlockedIncrement(&_lock_count) == 0) { - // Success, we now own the lock - } else { - DWORD dwRet = WaitForSingleObject((HANDLE)_lock_event, INFINITE); - assert(dwRet == WAIT_OBJECT_0); // Unexpected return value from WaitForSingleObject - } - assert(owner() == NULL); // Otherwise, lock count and owner are inconsistent - setOwner(GetCurrentThread()); -} - -void -Monitor::unlock() { - setOwner(NULL); - if (InterlockedDecrement(&_lock_count) >= 0) { - // Wake a waiting thread up - DWORD dwRet = SetEvent(_lock_event); - assert(dwRet != 0); // Unexpected return value from SetEvent - } -} - -bool -Monitor::wait(long timeout) { - assert(owner() != NULL); - assert(owner() == GetCurrentThread()); - - // 0 means forever. Convert to Windows specific code. - DWORD timeout_value = (timeout == 0) ? INFINITE : timeout; - DWORD which; - - long c = _counter; - bool retry = false; - - _waiters++; - // Loop until condition variable is signaled. The event object is - // set whenever the condition variable is signaled, and tickets will - // reflect the number of threads which have been notified. The counter - // field is used to make sure we don't respond to notifications that - // have occurred *before* we started waiting, and is incremented each - // time the condition variable is signaled. - - while (true) { - - // Leave critical region - unlock(); - - // If this is a retry, let other low-priority threads have a chance - // to run. Make sure that we sleep outside of the critical section. - if (retry) { - Sleep(1); - } else { - retry = true; - } - - which = WaitForSingleObject(_wait_event, timeout_value); - // Enter critical section - lock(); - - if (_tickets != 0 && _counter != c) break; - - if (which == WAIT_TIMEOUT) { - --_waiters; - return true; - } - } - _waiters--; - - // If this was the last thread to be notified, then we need to reset - // the event object. - if (--_tickets == 0) { - ResetEvent(_wait_event); - } - - return false; -} - -// Notify a single thread waiting on this monitor -bool -Monitor::notify() { - assert(ownedBySelf()); // Otherwise, notify on unknown thread - - if (_waiters > _tickets) { - if (!SetEvent(_wait_event)) { - return false; - } - _tickets++; - _counter++; - } - - return true; -} - -// Notify all threads waiting on this monitor -bool -Monitor::notifyAll() { - assert(ownedBySelf()); // Otherwise, notifyAll on unknown thread - - if (_waiters > 0) { - if (!SetEvent(_wait_event)) { - return false; - } - _tickets = _waiters; - _counter++; - } - - return true; -} - -HANDLE -Monitor::owner() { - return _owner; -} - -void -Monitor::setOwner(HANDLE owner) { - if (owner != NULL) { - assert(_owner == NULL); // Setting owner thread of already owned monitor - assert(owner == GetCurrentThread()); // Else should not be doing this - } else { - HANDLE oldOwner = _owner; - assert(oldOwner != NULL); // Removing the owner thread of an unowned mutex - assert(oldOwner == GetCurrentThread()); - } - _owner = owner; -} - -bool -Monitor::ownedBySelf() { - return (_owner == GetCurrentThread()); -}