1 files changed, 32 insertions, 0 deletions
diff --git a/src/rocksdb/utilities/merge_operators/string_append/stringappend.h b/src/rocksdb/utilities/merge_operators/string_append/stringappend.h
new file mode 100644
index 000000000..153532382
--- /dev/null
+++ b/src/rocksdb/utilities/merge_operators/string_append/stringappend.h
@@ -0,0 +1,32 @@
+/**
+ * A MergeOperator for rocksdb that implements string append.
+ * @author Deon Nicholas (dnicholas@fb.com)
+ * Copyright 2013 Facebook
+ */
+
+#pragma once
+#include "rocksdb/merge_operator.h"
+#include "rocksdb/slice.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class StringAppendOperator : public AssociativeMergeOperator {
+ public:
+  // Constructor: specify delimiter
+  explicit StringAppendOperator(char delim_char);
+  explicit StringAppendOperator(const std::string& delim);
+
+  virtual bool Merge(const Slice& key, const Slice* existing_value,
+                     const Slice& value, std::string* new_value,
+                     Logger* logger) const override;
+
+  static const char* kClassName() { return "StringAppendOperator"; }
+  static const char* kNickName() { return "stringappend"; }
+  virtual const char* Name() const override { return kClassName(); }
+  virtual const char* NickName() const override { return kNickName(); }
+
+ private:
+  std::string delim_;  // The delimiter is inserted between elements
+};
+
+}  // namespace ROCKSDB_NAMESPACE