From fb56ee788784bb285de4b56e981580756c61e477 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Tue, 17 Nov 2015 22:05:16 +0000
Subject: Improve core with traits and decltype for working with functions that
 return references to mutexes. Add support for upgradable locks

---
 libadhocutil/lockHelpers.h           | 29 ++++++++++++++++++-----------
 libadhocutil/unittests/testLocks.cpp | 17 +++++++++++++++++
 2 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/libadhocutil/lockHelpers.h b/libadhocutil/lockHelpers.h
index 5ac4bf7..1482644 100644
--- a/libadhocutil/lockHelpers.h
+++ b/libadhocutil/lockHelpers.h
@@ -1,13 +1,15 @@
 #ifndef ADHOCUTIL_LOCKHELPERS_H
 #define ADHOCUTIL_LOCKHELPERS_H
 
+#include <type_traits>
+
 /// @cond
 template <typename locktype>
-class _LockLoop {
+class _LockLoop : public locktype {
 	public:
-		template<typename l>
-		_LockLoop(l & _l) :
-			lock(_l),
+		template<typename MutexType>
+		_LockLoop(MutexType & m) :
+			locktype(m),
 			flag(true)
 		{
 		}
@@ -16,7 +18,6 @@ class _LockLoop {
 		void operator!() { flag = false; }
 
 	private:
-		locktype lock;
 		bool flag;
 };
 /// @endcond
@@ -24,15 +25,21 @@ class _LockLoop {
 #define LIBADHOC_LOCK_CONCAT2(a, b) a ## b
 #define LIBADHOC_LOCK_CONCAT(a, b) LIBADHOC_LOCK_CONCAT2(a, b)
 #define LIBADHOC_LOCK_WITHLINE(a) LIBADHOC_LOCK_CONCAT(a,  __LINE__)
+#define LIBADHOC_RRT(l) typename std::remove_reference<decltype(l)>::type
 
-#define BaseScopeLock(l,lt,mt) for (_LockLoop<lt<mt>> LIBADHOC_LOCK_WITHLINE(_lck)(l); LIBADHOC_LOCK_WITHLINE(_lck); !LIBADHOC_LOCK_WITHLINE(_lck))
-#define BaseLock(l,lt,mt) lt<mt> LIBADHOC_LOCK_WITHLINE(_lck)(l)
+#define BaseScopeLock(l,lt) for (_LockLoop<lt<LIBADHOC_RRT(l)>> LIBADHOC_LOCK_WITHLINE(_lck)(l); LIBADHOC_LOCK_WITHLINE(_lck); !LIBADHOC_LOCK_WITHLINE(_lck))
+#define TypeBaseLock(l,lt,mt) lt<mt> LIBADHOC_LOCK_WITHLINE(_lck)(l)
+#define BaseLock(l,lt) TypeBaseLock(l, lt, LIBADHOC_RRT(l))
 
-#define Lock(l) BaseLock(l, boost::unique_lock, boost::shared_mutex)
-#define SharedLock(l) BaseLock(l, boost::shared_lock, boost::shared_mutex)
+#define Lock(l) BaseLock(l, boost::unique_lock)
+#define SharedLock(l) BaseLock(l, boost::shared_lock)
+#define UpgradableLock(l, ln) boost::upgrade_lock<LIBADHOC_RRT(l)> ln(l)
+#define UpgradeLock(l) TypeBaseLock(l, boost::upgrade_to_unique_lock, LIBADHOC_RRT(l)::mutex_type)
 
-#define ScopeLock(l) BaseScopeLock(l, boost::unique_lock, boost::shared_mutex)
-#define SharedScopeLock(l) BaseScopeLock(l, boost::shared_lock, boost::shared_mutex)
+#define ScopeLock(l) BaseScopeLock(l, boost::unique_lock)
+#define SharedScopeLock(l) BaseScopeLock(l, boost::shared_lock)
+#define UpgradableScopeLock(l, ln) for (_LockLoop<boost::upgrade_lock<LIBADHOC_RRT(l)>> ln(l); ln; !ln)
+#define UpgradeScopeLock(l) for (_LockLoop<boost::upgrade_to_unique_lock<LIBADHOC_RRT(l)::mutex_type>> LIBADHOC_LOCK_WITHLINE(_lck)(l); LIBADHOC_LOCK_WITHLINE(_lck); !LIBADHOC_LOCK_WITHLINE(_lck))
 
 #endif
 
diff --git a/libadhocutil/unittests/testLocks.cpp b/libadhocutil/unittests/testLocks.cpp
index bdf0d18..4b0bad5 100644
--- a/libadhocutil/unittests/testLocks.cpp
+++ b/libadhocutil/unittests/testLocks.cpp
@@ -16,6 +16,14 @@ BOOST_AUTO_TEST_CASE ( sharedlock )
 	SharedLock(_lock);
 }
 
+BOOST_AUTO_TEST_CASE ( upgradelock )
+{
+	boost::upgrade_mutex _lock;
+	UpgradableLock(_lock, ln);
+	UpgradeScopeLock(ln) { }
+	UpgradeLock(ln);
+}
+
 BOOST_AUTO_TEST_CASE ( scopelock )
 {
 	boost::shared_mutex _lock;
@@ -28,3 +36,12 @@ BOOST_AUTO_TEST_CASE ( sharedscopelock )
 	SharedScopeLock(_lock) { }
 }
 
+BOOST_AUTO_TEST_CASE ( upgradescopelock )
+{
+	boost::upgrade_mutex _lock;
+	UpgradableScopeLock(_lock, ln) {
+		UpgradeScopeLock(ln) { }
+		UpgradeLock(ln);
+	}
+}
+
-- 
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