use partial blocks for oplog import (#780)

Feature: Add --allow-partial-block-requests to zen oplog-import
Improvement: zen oplog-import now uses partial block requests to reduce download size
Improvement: Use latency to Cloud Storage host and Zen Cache host when calculating partial block requests

1 files changed, 27 insertions, 0 deletions

diff --git a/src/zenremotestore/partialblockrequestmode.cpp b/src/zenremotestore/partialblockrequestmode.cpp
new file mode 100644
index 000000000..b3edf515b
--- /dev/null
+++ b/src/zenremotestore/partialblockrequestmode.cpp
@@ -0,0 +1,27 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenremotestore/partialblockrequestmode.h>
+
+#include <zencore/string.h>
+
+namespace zen {
+
+EPartialBlockRequestMode
+PartialBlockRequestModeFromString(const std::string_view ModeString)
+{
+	switch (HashStringAsLowerDjb2(ModeString))
+	{
+		case HashStringDjb2("false"):
+			return EPartialBlockRequestMode::Off;
+		case HashStringDjb2("zencacheonly"):
+			return EPartialBlockRequestMode::ZenCacheOnly;
+		case HashStringDjb2("mixed"):
+			return EPartialBlockRequestMode::Mixed;
+		case HashStringDjb2("true"):
+			return EPartialBlockRequestMode::All;
+		default:
+			return EPartialBlockRequestMode::Invalid;
+	}
+}
+
+}  // namespace zen