From c92cc9fe51a718b3ab33a3a9a2f4cbcec2edad11 Mon Sep 17 00:00:00 2001
From: "Adam C. Emerson" <aemerson@redhat.com>
Date: Fri, 23 Dec 2016 12:43:06 -0500
Subject: [PATCH] denc: Support boost::container::flat_set

Signed-off-by: Adam C. Emerson <aemerson@redhat.com>
---
 src/include/denc.h     | 10 ++++++++++
 src/include/encoding.h | 44 ++++++++++++++++++++++++++++++++++++++++++
 src/test/test_denc.cc  | 32 ++++++++++++++++++++++--------
 3 files changed, 78 insertions(+), 8 deletions(-)

diff --git a/src/include/denc.h b/src/include/denc.h
index e5631737109..58b542a453a 100644
--- a/src/include/denc.h
+++ b/src/include/denc.h
@@ -32,6 +32,7 @@
 #include <type_traits>
 #include <boost/intrusive/set.hpp>
 #include <boost/container/flat_map.hpp>
+#include <boost/container/flat_set.hpp>
 
 #include "include/int_types.h"
 #include "include/intarith.h"
@@ -821,6 +822,15 @@ struct denc_traits<
 				 _denc::setlike_details<std::set<T, Ts...>>,
 				 T, Ts...> {};
 
+template<typename T, typename ...Ts>
+struct denc_traits<
+  boost::container::flat_set<T, Ts...>,
+  typename std::enable_if<denc_traits<T>::supported != 0>::type>
+  : public _denc::container_base<
+  boost::container::flat_set,
+  _denc::setlike_details<boost::container::flat_set<T, Ts...>>,
+  T, Ts...> {};
+
 namespace _denc {
   template<typename Container>
   struct maplike_details : public container_details_base<Container> {
diff --git a/src/include/encoding.h b/src/include/encoding.h
index cbc762351d7..b8a358ef49a 100644
--- a/src/include/encoding.h
+++ b/src/include/encoding.h
@@ -504,6 +504,50 @@ inline typename std::enable_if<!traits::supported>::type
   }
 }
 
+// boost::container::flat_set<T>
+template<class T, class Comp, class Alloc, typename traits=denc_traits<T>>
+inline typename std::enable_if<!traits::supported>::type
+encode(const boost::container::flat_set<T, Comp, Alloc>& s, bufferlist& bl)
+{
+  __u32 n = (__u32)(s.size());
+  encode(n, bl);
+  for (const auto& e : s)
+    encode(e, bl);
+}
+template<class T, class Comp, class Alloc, typename traits=denc_traits<T>>
+inline typename std::enable_if<!traits::supported>::type
+decode(boost::container::flat_set<T, Comp, Alloc>& s, bufferlist::iterator& p)
+{
+  __u32 n;
+  decode(n, p);
+  s.clear();
+  while (n--) {
+    T v;
+    decode(v, p);
+    s.insert(v);
+  }
+}
+
+template<class T, class Comp, class Alloc, typename traits=denc_traits<T>>
+inline typename std::enable_if<!traits::supported>::type
+encode_nohead(const boost::container::flat_set<T, Comp, Alloc>& s,
+	      bufferlist& bl)
+{
+  for (const auto& e : s)
+    encode(e, bl);
+}
+template<class T, class Comp, class Alloc, typename traits=denc_traits<T>>
+inline typename std::enable_if<!traits::supported>::type
+decode_nohead(int len, boost::container::flat_set<T, Comp, Alloc>& s,
+	      bufferlist::iterator& p)
+{
+  for (int i=0; i<len; i++) {
+    T v;
+    decode(v, p);
+    s.insert(v);
+  }
+}
+
 // multiset
 template<class T, class Comp, class Alloc>
 inline void encode(const std::multiset<T,Comp,Alloc>& s, bufferlist& bl)
diff --git a/src/test/test_denc.cc b/src/test/test_denc.cc
index 3e79d83a940..12a5489f6c2 100644
--- a/src/test/test_denc.cc
+++ b/src/test/test_denc.cc
@@ -287,33 +287,49 @@ TEST(denc, list)
   }
 }
 
-TEST(denc, set)
-{
+template<template<class> class C>
+void test_setlike(const char* c) {
   {
-    cout << "set<string>" << std::endl;
-    std::set<string> s;
+    cout << c << "<std::string>" << std::endl;
+    C<std::string> s;
     s.insert("foo");
     s.insert("bar");
     s.insert("baz");
     test_denc(s);
   }
   {
-    cout << "set<int32_t>" << std::endl;
-    std::set<int32_t> s;
+    cout << c << "<int32_t>" << std::endl;
+    C<int32_t> s;
     s.insert(1);
     s.insert(2);
     s.insert(3);
     test_denc(s);
   }
   {
-    cout << "set<legacy_t>" << std::endl;
-    std::set<legacy_t> s;
+    cout << c << "<legacy_t>" << std::endl;
+    C<legacy_t> s;
     s.insert(legacy_t(1));
     s.insert(legacy_t(2));
     test_encode_decode(s);
   }
 }
 
+template<typename T>
+using default_set = std::set<T>;
+
+TEST(denc, set)
+{
+  test_setlike<default_set>("std::set");
+}
+
+template<typename T>
+using default_flat_set= boost::container::flat_set<T>;
+
+TEST(denc, flat_set)
+{
+  test_setlike<default_flat_set>("std::set");
+}
+
 struct foo_t {
   int32_t a = 0;
   uint64_t b = 123;