oplog snapshot (#317)

Added "snapshot" oplog RPC

this may be used to bring referenced files into the local store instead of referencing them by filename, thus making the project/oplog transportable

1 files changed, 42 insertions, 0 deletions

diff --git a/src/zencore/include/zencore/compactbinaryutil.h b/src/zencore/include/zencore/compactbinaryutil.h
new file mode 100644
index 000000000..9d69266bf
--- /dev/null
+++ b/src/zencore/include/zencore/compactbinaryutil.h
@@ -0,0 +1,42 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zencore/zencore.h>
+
+#include <zencore/compactbinary.h>
+#include <zencore/compactbinarybuilder.h>
+
+namespace zen {
+
+/** Object rewrite helper
+
+	This is meant to be used when you have a fully formed CbObject which you wish
+	to rewrite. Since the compact binary format is not meant for in-place updates
+	this involves scanning the object, copying the fields we want to keep and
+	writing new versions of the fields we wish to keep.
+
+	The Rewriter function accepts a reference to the CbObjectWriter which is being
+	used to build the new version of the object and a reference to a field which is
+	considered for copy or rewriting. If the function wants to rewrite a field then
+	it'll use the writer to write a new field and then return `true`, otherwise just
+	return `false` to have RewriteCbObject copy the field into the new object.
+*/
+
+CbObject
+RewriteCbObject(CbObjectView InObj, Invocable<CbObjectWriter&, CbFieldView&> auto Rewriter)
+{
+	CbObjectWriter CboWriter;
+
+	for (CbFieldView InnerField : InObj)
+	{
+		if (!Rewriter(CboWriter, InnerField))
+		{
+			CboWriter.AddField(InnerField.GetName(), InnerField);
+		}
+	}
+
+	return CboWriter.Save();
+}
+
+}  // namespace zen