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Diffstat (limited to 'libs/pbd/glib_semaphore.cc')
-rw-r--r-- | libs/pbd/glib_semaphore.cc | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/libs/pbd/glib_semaphore.cc b/libs/pbd/glib_semaphore.cc new file mode 100644 index 0000000000..7565e0c069 --- /dev/null +++ b/libs/pbd/glib_semaphore.cc @@ -0,0 +1,68 @@ +/* + Copyright (C) 2010 Tim Mayberry + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program 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 for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + +*/ + +#include "pbd/glib_semaphore.h" + +namespace PBD { + +GlibSemaphore::GlibSemaphore (gint initial_val) + : + m_counter(initial_val) +{ } + +void +GlibSemaphore::wait () +{ + Glib::Threads::Mutex::Lock guard (m_mutex); + + while (m_counter.get() < 1) { + m_cond.wait(m_mutex); + } + + // this shouldn't need to be inside the lock + --m_counter; +} + +bool +GlibSemaphore::try_wait () +{ + if (!m_mutex.trylock()) + { + return false; + } + // lock successful + while (m_counter.get() < 1) { + m_cond.wait(m_mutex); + } + + // the order of these should not matter + --m_counter; + m_mutex.unlock(); + return true; +} + +void +GlibSemaphore::post () +{ + // atomic, no locking required + ++m_counter; + m_cond.signal(); +} + +} // namespace PBD |