Add GC Cancel/Stop (#568)

- GcScheduler will now cancel any running GC when it shuts down.
  - Old GC is rather limited in *when* it reacts to cancel of GC. GCv2 is more responsive.

1 files changed, 20 insertions, 2 deletions

diff --git a/src/zenstore/filecas.cpp b/src/zenstore/filecas.cpp
index 2623e157d..6ba282163 100644
--- a/src/zenstore/filecas.cpp
+++ b/src/zenstore/filecas.cpp
@@ -44,6 +44,15 @@ ZEN_THIRD_PARTY_INCLUDES_END
 
 namespace zen {
 
+namespace {
+	template<typename T>
+	void Reset(T& V)
+	{
+		T Tmp;
+		V.swap(Tmp);
+	}
+}  // namespace
+
 namespace filecas::impl {
 	const char* IndexExtension = ".uidx";
 	const char* LogExtension   = ".ulog";
@@ -1345,6 +1354,7 @@ public:
 	{
 		Stopwatch  Timer;
 		const auto _ = MakeGuard([&] {
+			Reset(m_ReferencesToClean);
 			if (!Ctx.Settings.Verbose)
 			{
 				return;
@@ -1366,6 +1376,11 @@ public:
 					// Not regarded as pruned, leave it be
 					continue;
 				}
+				if (Ctx.IsCancelledFlag.load())
+				{
+					return;
+				}
+
 				if (Ctx.Settings.IsDeleteMode)
 				{
 					ZEN_DEBUG("GCV2: filecas [COMPACT] '{}': Deleting CAS payload file '{}'",
@@ -1418,8 +1433,7 @@ public:
 			ZEN_DEBUG("GCV2: filecas [COMPACT] '{}': Skipped deleting of {} eligible files", m_FileCasStrategy.m_RootDirectory, Skipped);
 		}
 
-		m_ReferencesToClean.clear();
-		m_ReferencesToClean.shrink_to_fit();
+		Reset(m_ReferencesToClean);
 	}
 
 private:
@@ -1521,6 +1535,10 @@ FileCasStrategy::CreateReferencePruner(GcCtx& Ctx, GcReferenceStoreStats&)
 		{
 			return {};
 		}
+		if (Ctx.IsCancelledFlag.load())
+		{
+			return nullptr;
+		}
 		CidsToCheck.reserve(m_Index.size());
 		for (const auto& It : m_Index)
 		{