Issue #4826 - Use latch to replace thread-sleeping in tests

src/Latch.cpp

+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2016 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus 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 Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "Latch.h"
+
+void Latch::Arrive()
+{
+  UniqueLockType ul(m);
+  if (count <= 0)
+  {
+    throw std::logic_error("May not decrement count below zero");
+  }
+  --count;
+  if (synchronizationCondition())
+  {
+    cv.notify_all();
+  }
+}
+
+void Latch::Wait()
+{
+  UniqueLockType ul(m);
+  if (synchronizationCondition())
+  {
+    return;
+  }
+  cv.wait(ul, [this]() -> bool { return synchronizationCondition(); });
+}
+
+bool Latch::TryWait()
+{
+  UniqueLockType ul(m);
+  return synchronizationCondition();
+}