00001 // Filename: mutexSimpleImpl.cxx 00002 // Created by: drose (19Jun07) 00003 // 00004 //////////////////////////////////////////////////////////////////// 00005 // 00006 // PANDA 3D SOFTWARE 00007 // Copyright (c) Carnegie Mellon University. All rights reserved. 00008 // 00009 // All use of this software is subject to the terms of the revised BSD 00010 // license. You should have received a copy of this license along 00011 // with this source code in a file named "LICENSE." 00012 // 00013 //////////////////////////////////////////////////////////////////// 00014 00015 #include "selectThreadImpl.h" 00016 00017 #ifdef THREAD_SIMPLE_IMPL 00018 00019 #include "mutexSimpleImpl.h" 00020 #include "threadSimpleImpl.h" 00021 #include "threadSimpleManager.h" 00022 00023 //////////////////////////////////////////////////////////////////// 00024 // Function: MutexSimpleImpl::do_acquire 00025 // Access: Private 00026 // Description: 00027 //////////////////////////////////////////////////////////////////// 00028 void MutexSimpleImpl:: 00029 do_acquire() { 00030 // By the time we get here, we already know that someone else is 00031 // holding the lock: (_flags & F_lock_count) != 0. 00032 ThreadSimpleManager *manager = ThreadSimpleManager::get_global_ptr(); 00033 ThreadSimpleImpl *thread = manager->get_current_thread(); 00034 00035 while ((_flags & F_lock_count) != 0) { 00036 manager->enqueue_block(thread, this); 00037 manager->next_context(); 00038 } 00039 00040 _flags |= F_lock_count; 00041 } 00042 00043 //////////////////////////////////////////////////////////////////// 00044 // Function: MutexSimpleImpl::do_release 00045 // Access: Private 00046 // Description: 00047 //////////////////////////////////////////////////////////////////// 00048 void MutexSimpleImpl:: 00049 do_release() { 00050 // By the time we get here, we already know that someone else is 00051 // blocked on this mutex: (_flags & F_waiters) != 0. 00052 ThreadSimpleManager *manager = ThreadSimpleManager::get_global_ptr(); 00053 if (manager->unblock_one(this)) { 00054 // There had been a thread waiting on this mutex. Switch contexts 00055 // immediately, to make fairness more likely. 00056 ThreadSimpleImpl *thread = manager->get_current_thread(); 00057 manager->enqueue_ready(thread, false); 00058 manager->next_context(); 00059 } 00060 } 00061 00062 //////////////////////////////////////////////////////////////////// 00063 // Function: MutexSimpleImpl::do_release_quietly 00064 // Access: Private 00065 // Description: 00066 //////////////////////////////////////////////////////////////////// 00067 void MutexSimpleImpl:: 00068 do_release_quietly() { 00069 ThreadSimpleManager *manager = ThreadSimpleManager::get_global_ptr(); 00070 manager->unblock_one(this); 00071 } 00072 00073 #endif // THREAD_SIMPLE_IMPL