renderer: optimizing and fixing code paths

Re-introducing some old concepts for the new structure.

app/render/backend/renderticket.cpp

@@ -0,0 +1,103 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2019 Olive Team
+
+  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 3 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, see <http://www.gnu.org/licenses/>.
+
+***/
+
+#include "renderticket.h"
+
+OLIVE_NAMESPACE_ENTER
+
+RenderTicket::RenderTicket(Type type, const TimeRange &time) :
+  finished_(false),
+  cancelled_(false),
+  time_(time),
+  type_(type)
+{
+}
+
+void RenderTicket::WaitForFinished()
+{
+  QMutexLocker locker(&lock_);
+
+  if (!finished_) {
+    wait_.wait(&lock_);
+  }
+}
+
+QVariant RenderTicket::Get()
+{
+  QMutexLocker locker(&lock_);
+
+  if (!finished_) {
+    wait_.wait(&lock_);
+  }
+
+  return result_;
+}
+
+bool RenderTicket::IsFinished(bool lock)
+{
+  if (lock) {
+    lock_.lock();
+  }
+
+  bool finished = finished_;
+
+  if (lock) {
+    lock_.unlock();
+  }
+
+  return finished;
+}
+
+bool RenderTicket::WasCancelled()
+{
+  QMutexLocker locker(&lock_);
+
+  return cancelled_;
+}
+
+void RenderTicket::Finish(QVariant result)
+{
+  QMutexLocker locker(&lock_);
+
+  finished_ = true;
+  result_ = result;
+
+  wait_.wakeAll();
+
+  locker.unlock();
+
+  emit Finished();
+}
+
+void RenderTicket::Cancel()
+{
+  QMutexLocker locker(&lock_);
+
+  finished_ = true;
+  cancelled_ = true;
+
+  wait_.wakeAll();
+
+  locker.unlock();
+
+  emit Finished();
+}
+
+OLIVE_NAMESPACE_EXIT