Add GetStringFromCompressionType to include/rocksdb/convenience.h

Summary:
Expose a simple function to convert CompressionType to it's corresponding option string

This is for a diff @yoshinorim is working on for MyRocks

Test Plan: unittest

Reviewers: yhchiang, andrewkr, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, yoshinorim

Differential Revision: https://reviews.facebook.net/D58215

include/rocksdb/convenience.h

@@ -5,8 +5,10 @@
 
 #pragma once
 
-#include <unordered_map>
 #include <string>
+#include <unordered_map>
+#include <vector>
+
 #include "rocksdb/db.h"
 #include "rocksdb/options.h"
 #include "rocksdb/table.h"
@@ -76,6 +78,9 @@ Status GetStringFromColumnFamilyOptions(std::string* opts_str,
                                         const ColumnFamilyOptions& db_options,
                                         const std::string& delimiter = ";  ");
 
+Status GetStringFromCompressionType(std::string* compression_str,
+                                    CompressionType compression_type);
+
 Status GetBlockBasedTableOptionsFromString(
     const BlockBasedTableOptions& table_options,
     const std::string& opts_str,

util/options_helper.cc

@@ -955,6 +955,17 @@ Status GetStringFromColumnFamilyOptions(std::string* opt_string,
   return Status::OK();
 }
 
+Status GetStringFromCompressionType(std::string* compression_str,
+                                    CompressionType compression_type) {
+  bool ok = SerializeEnum<CompressionType>(compression_type_string_map,
+                                           compression_type, compression_str);
+  if (ok) {
+    return Status::OK();
+  } else {
+    return Status::InvalidArgument("Invalid compression types");
+  }
+}
+
 bool SerializeSingleBlockBasedTableOption(
     std::string* opt_string, const BlockBasedTableOptions& bbt_options,
     const std::string& name, const std::string& delimiter) {

util/options_test.cc

@@ -836,6 +836,28 @@ TEST_F(OptionsTest, StringToMapRandomTest) {
     opts_map.clear();
   }
 }
+
+TEST_F(OptionsTest, GetStringFromCompressionType) {
+  std::string res;
+
+  ASSERT_OK(GetStringFromCompressionType(&res, kNoCompression));
+  ASSERT_EQ(res, "kNoCompression");
+
+  ASSERT_OK(GetStringFromCompressionType(&res, kSnappyCompression));
+  ASSERT_EQ(res, "kSnappyCompression");
+
+  ASSERT_OK(GetStringFromCompressionType(&res, kDisableCompressionOption));
+  ASSERT_EQ(res, "kDisableCompressionOption");
+
+  ASSERT_OK(GetStringFromCompressionType(&res, kLZ4Compression));
+  ASSERT_EQ(res, "kLZ4Compression");
+
+  ASSERT_OK(GetStringFromCompressionType(&res, kZlibCompression));
+  ASSERT_EQ(res, "kZlibCompression");
+
+  ASSERT_NOK(
+      GetStringFromCompressionType(&res, static_cast<CompressionType>(-10)));
+}
 #endif  // !ROCKSDB_LITE
 
 TEST_F(OptionsTest, ConvertOptionsTest) {