From 89231894c7cd095b811129ca034e31b9017610fb Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Wed, 18 Nov 2015 01:25:50 +0000
Subject: Implement and test resource testing and replacement on reuse.

---
 libadhocutil/resourcePool.h                 |  2 +-
 libadhocutil/resourcePool.impl.h            | 32 ++++++++++++++-----------
 libadhocutil/unittests/testResourcePool.cpp | 37 +++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+), 15 deletions(-)

diff --git a/libadhocutil/resourcePool.h b/libadhocutil/resourcePool.h
index f3683ae..5ccb516 100644
--- a/libadhocutil/resourcePool.h
+++ b/libadhocutil/resourcePool.h
@@ -76,7 +76,7 @@ namespace AdHoc {
 			/// Create a new resource instance to add to the pool.
 			virtual Resource * createResource() const = 0;
 			/// Destroy an existing resource (defaults to delete).
-			virtual void destroyResource(Resource *) const;
+			virtual void destroyResource(Resource *) const throw();
 			/// Test a cached resource is still suitable for use (defaults to no-op).
 			virtual void testResource(const Resource *) const;
 
diff --git a/libadhocutil/resourcePool.impl.h b/libadhocutil/resourcePool.impl.h
index d4fcfe4..85a6d3d 100644
--- a/libadhocutil/resourcePool.impl.h
+++ b/libadhocutil/resourcePool.impl.h
@@ -98,7 +98,7 @@ namespace AdHoc {
 
 	template <typename R>
 	void
-	ResourcePool<R>::destroyResource(R * r) const
+	ResourcePool<R>::destroyResource(R * r) const throw()
 	{
 		delete r;
 	}
@@ -166,20 +166,24 @@ namespace AdHoc {
 	ResourceHandle<R>
 	ResourcePool<R>::getOne()
 	{
-		UpgradableLock(lock, ulock);
-		if (available.empty()) {
-			auto ro = new typename ResourceHandle<R>::Object(createResource(), this);
-			UpgradeLock(ulock);
-			inUse.insert({ std::this_thread::get_id(), ro });
-			return ro;
-		}
-		else {
-			UpgradeLock(ulock);
-			auto ro = new typename ResourceHandle<R>::Object(available.front(), this);
-			available.pop_front();
-			inUse.insert({ std::this_thread::get_id(), ro });
-			return ro;
+		Lock(lock);
+		while (!available.empty()) {
+			auto r = available.front();
+			try {
+				testResource(r);
+				auto ro = new typename ResourceHandle<R>::Object(r, this);
+				available.pop_front();
+				inUse.insert({ std::this_thread::get_id(), ro });
+				return ro;
+			}
+			catch (...) {
+				destroyResource(r);
+				available.pop_front();
+			}
 		}
+		auto ro = new typename ResourceHandle<R>::Object(createResource(), this);
+		inUse.insert({ std::this_thread::get_id(), ro });
+		return ro;
 	}
 
 	template <typename R>
diff --git a/libadhocutil/unittests/testResourcePool.cpp b/libadhocutil/unittests/testResourcePool.cpp
index 6e62730..349ea00 100644
--- a/libadhocutil/unittests/testResourcePool.cpp
+++ b/libadhocutil/unittests/testResourcePool.cpp
@@ -245,3 +245,40 @@ BOOST_AUTO_TEST_CASE( threading2 )
 	BOOST_REQUIRE_EQUAL(1, pool.availableCount());
 }
 
+class TTRP : public TRP {
+	public:
+		TTRP() : n(0) { }
+		void testResource(const MockResource *) const override
+		{
+			n += 1;
+			if (n % 2) {
+				throw std::exception();
+			}
+		}
+	private:
+		mutable int n;
+};
+
+BOOST_AUTO_TEST_CASE( test )
+{
+	TTRP pool;
+	MockResource * rp;
+	{
+		auto r = pool.get();
+		rp = r.get();
+	}
+	{
+		auto r = pool.get();
+		BOOST_REQUIRE(r.get());
+		BOOST_REQUIRE(rp != r.get());
+		BOOST_REQUIRE_EQUAL(1, MockResource::count);
+		rp = r.get();
+	}
+	{
+		auto r = pool.get();
+		BOOST_REQUIRE(r.get());
+		BOOST_REQUIRE(rp == r.get());
+		BOOST_REQUIRE_EQUAL(1, MockResource::count);
+	}
+}
+
-- 
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