[ldb] Export LDBCommandRunner

Summary:
The implementation remains where it is. Only the
header is exported. This is so that a customized
ldb tool can print help along with its own
extra commands

Test Plan: make ldb

Reviewers: sdong, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57255

include/rocksdb/utilities/ldb_cmd.h

@@ -230,6 +230,15 @@ class LDBCommand {
       const std::vector<std::string>& flags);
 };
 
+class LDBCommandRunner {
+ public:
+  static void PrintHelp(const char* exec_name);
+
+  static void RunCommand(
+      int argc, char** argv, Options options, const LDBOptions& ldb_options,
+      const std::vector<ColumnFamilyDescriptor>* column_families);
+};
+
 }  // namespace rocksdb
 
 #endif  // ROCKSDB_LITE

tools/ldb_tool.cc

@@ -12,10 +12,7 @@ namespace rocksdb {
 
 LDBOptions::LDBOptions() {}
 
-class LDBCommandRunner {
+void LDBCommandRunner::PrintHelp(const char* exec_name) {
-public:
-
-  static void PrintHelp(const char* exec_name) {
   std::string ret;
 
   ret.append("ldb - LevelDB Tool");
@@ -23,7 +20,8 @@ public:
   ret.append("commands MUST specify --" + LDBCommand::ARG_DB +
              "=<full_path_to_db_directory> when necessary\n");
   ret.append("\n");
-    ret.append("The following optional parameters control if keys/values are "
+  ret.append(
+      "The following optional parameters control if keys/values are "
       "input/output as hex or as plain strings:\n");
   ret.append("  --" + LDBCommand::ARG_KEY_HEX +
              " : Keys are input/output as hex\n");
@@ -37,7 +35,8 @@ public:
       "family\n");
   ret.append("\n");
 
-    ret.append("The following optional parameters control the database "
+  ret.append(
+      "The following optional parameters control the database "
       "internals:\n");
   ret.append("  --" + LDBCommand::ARG_TTL +
              " with 'put','get','scan','dump','query','batchput'"
@@ -48,8 +47,7 @@ public:
              "=<no|snappy|zlib|bzip2|lz4|lz4hc|xpress|zstd>\n");
   ret.append("  --" + LDBCommand::ARG_COMPRESSION_MAX_DICT_BYTES +
              "=<int,e.g.:14>\n");
-    ret.append("  --" + LDBCommand::ARG_BLOCK_SIZE +
+  ret.append("  --" + LDBCommand::ARG_BLOCK_SIZE + "=<block_size_in_bytes>\n");
-        "=<block_size_in_bytes>\n");
   ret.append("  --" + LDBCommand::ARG_AUTO_COMPACTION + "=<true|false>\n");
   ret.append("  --" + LDBCommand::ARG_DB_WRITE_BUFFER_SIZE +
              "=<int,e.g.:16777216>\n");
@@ -83,9 +81,9 @@ public:
   RepairCommand::Help(ret);
 
   fprintf(stderr, "%s\n", ret.c_str());
-  }
+}
 
-  static void RunCommand(
+void LDBCommandRunner::RunCommand(
     int argc, char** argv, Options options, const LDBOptions& ldb_options,
     const std::vector<ColumnFamilyDescriptor>* column_families) {
   if (argc <= 2) {
@@ -111,9 +109,7 @@ public:
   delete cmdObj;
 
   exit(ret.IsFailed());
-  }
+}
-
-};
 
 void LDBTool::Run(int argc, char** argv, Options options,
                   const LDBOptions& ldb_options,