Add Exit Hooks to ToolHooks (facebook#13772)

Summary:
This diff introduces the ability to override behavior of exits, allow for users to catch exits in a try catch for example as opposed to fully exiting the process.

Pull Request resolved: facebook#13772

Reviewed By: hx235

Differential Revision: D78244499

Pulled By: krhancoc

fbshipit-source-id: b403327ed5b494a22b6beeaad4083945a1def0c7

Author: Ryan Hancock

include/rocksdb/tool_hooks.h

@@ -69,6 +69,7 @@ class ToolHooks {
   virtual Status Open(const Options& options,
                       const blob_db::BlobDBOptions& bdb_options,
                       const std::string& dbname, blob_db::BlobDB** blob_db) = 0;
+  virtual void Exit(int status) = 0;
 };
 
 class DefaultHooks : public ToolHooks {
@@ -117,6 +118,8 @@ class DefaultHooks : public ToolHooks {
                       const blob_db::BlobDBOptions& bdb_options,
                       const std::string& dbname,
                       blob_db::BlobDB** blob_db) override;
+
+  virtual void Exit(int status) override { exit(status); }
 };
 
 extern DefaultHooks defaultHooks;