From 65fb399ebb166e90a0fafd93aee0536030ded90b Mon Sep 17 00:00:00 2001
From: Kefu Chai <kchai@redhat.com>
Date: Fri, 24 Mar 2017 13:38:04 +0800
Subject: [PATCH] include/denc: add missing {encode,decode}_nohead for
 denc_traits

implement {encode,decode}_nohead() for dec_traits<basic_string> and
bufferlist.

so compiler can find an appropriate version of decode_nohead() when
performing overload resolution. in some architectures, compiler resolves
the __u32 to size_t, which leads to a compilation failure, because the
compiler fails to instantiate the ::decode_nohead() template exposing
traits::decode_nohead().

Fixes: http://tracker.ceph.com/issues/18938
Signed-off-by: Kefu Chai <kchai@redhat.com>
---
 src/include/denc.h   | 19 +++++++++++++++++++
 src/test/encoding.cc | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/src/include/denc.h b/src/include/denc.h
index 350178085b8..355b64b3a62 100644
--- a/src/include/denc.h
+++ b/src/include/denc.h
@@ -546,11 +546,19 @@ public:
 		     uint64_t f=0) {
     uint32_t len;
     ::denc(len, p);
+    decode_nohead(len, s, p);
+  }
+  static void decode_nohead(size_t len, value_type& s,
+			    buffer::ptr::iterator& p) {
     s.clear();
     if (len) {
       s.append(p.get_pos_add(len), len);
     }
   }
+  static void encode_nohead(const value_type& s,
+			    buffer::list::contiguous_appender& p) {
+    p.append(s.data(), s.length());
+  }
 };
 
 //
@@ -598,6 +606,17 @@ struct denc_traits<bufferlist> {
     v.clear();
     v.push_back(p.get_ptr(len));
   }
+  static void encode_nohead(const bufferlist& v,
+			    buffer::list::contiguous_appender& p) {
+    p.append(v);
+  }
+  static void decode_nohead(size_t len, bufferlist& v,
+			    buffer::ptr::iterator& p) {
+    v.clear();
+    if (len) {
+      v.append(p.get_ptr(len));
+    }
+  }
 };
 
 //
diff --git a/src/test/encoding.cc b/src/test/encoding.cc
index 6a8da8b4b0b..29c3b99fddc 100644
--- a/src/test/encoding.cc
+++ b/src/test/encoding.cc
@@ -32,6 +32,40 @@ TEST(EncodingRoundTrip, StringNewline) {
   test_encode_and_decode < std::string >(my_str);
 }
 
+template <typename Size, typename T>
+static void test_encode_and_nohead_nohead(Size len, const T& src)
+{
+  bufferlist bl(1000000);
+  encode(len, bl);
+  encode_nohead(src, bl);
+  T dst;
+  bufferlist::iterator i(bl.begin());
+  decode(len, i);
+  decode_nohead(len, dst, i);
+  ASSERT_EQ(src, dst) << "Encoding roundtrip changed the string: orig=" << src << ", but new=" << dst;
+}
+
+TEST(EncodingRoundTrip, StringNoHead) {
+  const string str("The quick brown fox jumps over the lazy dog");
+  auto size = str.size();
+  test_encode_and_nohead_nohead(static_cast<int>(size), str);
+  test_encode_and_nohead_nohead(static_cast<unsigned>(size), str);
+  test_encode_and_nohead_nohead(static_cast<uint32_t>(size), str);
+  test_encode_and_nohead_nohead(static_cast<__u32>(size), str);
+  test_encode_and_nohead_nohead(static_cast<size_t>(size), str);
+}
+
+TEST(EncodingRoundTrip, BufferListNoHead) {
+  bufferlist bl;
+  bl.append("is this a dagger which i see before me?");
+  auto size = bl.length();
+  test_encode_and_nohead_nohead(static_cast<int>(size), bl);
+  test_encode_and_nohead_nohead(static_cast<unsigned>(size), bl);
+  test_encode_and_nohead_nohead(static_cast<uint32_t>(size), bl);
+  test_encode_and_nohead_nohead(static_cast<__u32>(size), bl);
+  test_encode_and_nohead_nohead(static_cast<size_t>(size), bl);
+}
+
 typedef std::multimap < int, std::string > multimap_t;
 typedef multimap_t::value_type my_val_ty;
 
-- 
2.39.5