From 824c20b76da7d87ba27ae8701700d2cd8f210a3c Mon Sep 17 00:00:00 2001
From: "Raphael S. Carvalho" <raphaelsc@scylladb.com>
Date: Wed, 31 Oct 2018 00:18:33 -0200
Subject: [PATCH] sstables: add sstable's on closed handling

Motivation is that it will be useful for catching regression on compaction
when releasing early exhausted sstables. That's because sstable's space
is only released once it's closed. So this will allow us to write a test
case and possibly use it for entities holding exhausted sstable.

Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
---
 sstables/sstables.cc | 2 ++
 sstables/sstables.hh | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/sstables/sstables.cc b/sstables/sstables.cc
index 09ab91efee..193bcff8a5 100644
--- a/sstables/sstables.cc
+++ b/sstables/sstables.cc
@@ -4126,6 +4126,8 @@ sstable::~sstable() {
         }
 
     }
+
+    _on_closed(*this);
 }
 
 sstring
diff --git a/sstables/sstables.hh b/sstables/sstables.hh
index 5a44e50153..c7500527bb 100644
--- a/sstables/sstables.hh
+++ b/sstables/sstables.hh
@@ -61,6 +61,7 @@
 #include "db/large_partition_handler.hh"
 #include "column_translation.hh"
 #include "stats.hh"
+#include "utils/observable.hh"
 
 #include <seastar/util/optimized_optional.hh>
 
@@ -388,6 +389,10 @@ public:
     }
     std::vector<sstring> component_filenames() const;
 
+    utils::observer<sstable&> add_on_closed_handler(std::function<void (sstable&)> on_closed_handler) noexcept {
+        return _on_closed.observe(on_closed_handler);
+    }
+
     template<typename Func, typename... Args>
     auto sstable_write_io_check(Func&& func, Args&&... args) const {
         return do_io_check(_write_error_handler, func, std::forward<Args>(args)...);
@@ -429,6 +434,7 @@ private:
     stdx::optional<dht::decorated_key> _first;
     stdx::optional<dht::decorated_key> _last;
     utils::UUID _run_identifier;
+    utils::observable<sstable&> _on_closed;
 
     lw_shared_ptr<file_input_stream_history> _single_partition_history = make_lw_shared<file_input_stream_history>();
     lw_shared_ptr<file_input_stream_history> _partition_range_history = make_lw_shared<file_input_stream_history>();