Postfix for #7197: Segfault in linux CS after successful detach from database: add forgotten new file

Author: AlexPeshkoff

src/jrd/ThreadCollect.h

@@ -0,0 +1,138 @@
+/*
+ *	PROGRAM:	JRD threading support
+ *	MODULE:		ThreadCollect.h
+ *	DESCRIPTION:	Threads' group completion handling
+ *
+ *  The contents of this file are subject to the Initial
+ *  Developer's Public License Version 1.0 (the "License");
+ *  you may not use this file except in compliance with the
+ *  License. You may obtain a copy of the License at
+ *  http://www.firebirdsql.org/en/initial-developer-s-public-license-version-1-0/
+ *
+ *  Software distributed under the License is distributed AS IS,
+ *  WITHOUT WARRANTY OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing rights
+ *  and limitations under the License.
+ *
+ *  The Original Code was created by Alexander Peshkov
+ *  for the Firebird Open Source RDBMS project.
+ *
+ *  Copyright (c) 2018, 2022 Alexander Peshkov <[email protected]>
+ *  and all contributors signed below.
+ *
+ *  All Rights Reserved.
+ *  Contributor(s): ______________________________________.
+ *
+ *
+ */
+
+#ifndef JRD_THREADCOLLECT_H
+#define JRD_THREADCOLLECT_H
+
+#include "../common/ThreadStart.h"
+#include "../common/classes/alloc.h"
+#include "../common/classes/array.h"
+#include "../common/classes/locks.h"
+
+
+namespace Jrd {
+
+	class ThreadCollect
+	{
+	public:
+		ThreadCollect(MemoryPool& p)
+			: threads(p)
+		{ }
+
+		void join()
+		{
+			if (!threads.hasData())
+				return;
+
+			waitFor(threads);
+		}
+
+		void ending(Thread::Handle& h)
+		{
+			// put thread into completion wait queue when it finished running
+			Firebird::MutexLockGuard g(threadsMutex, FB_FUNCTION);
+
+			for (unsigned n = 0; n < threads.getCount(); ++n)
+			{
+				if (threads[n].hndl == h)
+				{
+					threads[n].ending = true;
+					return;
+				}
+			}
+
+			Thrd t = {h, true};
+			threads.add(t);
+		}
+
+		void running(Thread::Handle& h)
+		{
+			// put thread into completion wait queue when it starts running
+			Firebird::MutexLockGuard g(threadsMutex, FB_FUNCTION);
+
+			Thrd t = {h, false};
+			threads.add(t);
+		}
+
+		void houseKeeping()
+		{
+			if (!threads.hasData())
+				return;
+
+			// join finished threads
+			AllThreads t;
+			{ // mutex scope
+				Firebird::MutexLockGuard g(threadsMutex, FB_FUNCTION);
+
+				for (unsigned n = 0; n < threads.getCount(); )
+				{
+					if (threads[n].ending)
+					{
+						t.add(threads[n]);
+						threads.remove(n);
+					}
+					else
+						++n;
+				}
+			}
+
+			waitFor(t);
+		}
+
+	private:
+		struct Thrd
+		{
+			Thread::Handle hndl;
+			bool ending;
+		};
+		typedef Firebird::HalfStaticArray<Thrd, 4> AllThreads;
+
+		void waitFor(AllThreads& thr)
+		{
+			Firebird::MutexLockGuard g(threadsMutex, FB_FUNCTION);
+			while (thr.hasData())
+			{
+				FB_SIZE_T n = thr.getCount() - 1;
+				Thrd& t = thr[n];
+				{
+					Firebird::MutexUnlockGuard u(threadsMutex, FB_FUNCTION);
+					Thread::waitForCompletion(t.hndl);
+					fb_assert(t.ending);
+				}
+				thr.remove(n);
+			}
+		}
+
+		AllThreads threads;
+		Firebird::Mutex threadsMutex;
+	};
+
+}	// namespace Jrd
+
+
+#endif	// JRD_THREADCOLLECT_H