Support deserializing into temporaries

Currently, the READWRITE macro cannot be passed any non-const temporaries, as
the SerReadWrite function only accepts lvalue references.

Deserializing into a temporary is very common, however. See for example
things like 's >> VARINT(n)'. The VARINT macro produces a temporary wrapper
that holds a reference to n.

Fix this by accepting non-const rvalue references instead of lvalue references.
We don't propagate the rvalue-ness down, as there are no useful optimizations
that only apply to temporaries.

Then use this new functionality to get rid of many (but not all) uses of the
'REF' macro (which casts away constness).

9 files changed, 28 insertions, 28 deletions

diff --git a/src/blockencodings.h b/src/blockencodings.h
index ba8c1d6a2a..f80821aa65 100644
--- a/src/blockencodings.h
+++ b/src/blockencodings.h
@@ -90,11 +90,11 @@ public:
             while (txn.size() < txn_size) {
                 txn.resize(std::min((uint64_t)(1000 + txn.size()), txn_size));
                 for (; i < txn.size(); i++)
-                    READWRITE(REF(TransactionCompressor(txn[i])));
+                    READWRITE(TransactionCompressor(txn[i]));
             }
         } else {
             for (size_t i = 0; i < txn.size(); i++)
-                READWRITE(REF(TransactionCompressor(txn[i])));
+                READWRITE(TransactionCompressor(txn[i]));
         }
     }
 };
@@ -115,7 +115,7 @@ struct PrefilledTransaction {
         if (idx > std::numeric_limits<uint16_t>::max())
             throw std::ios_base::failure("index overflowed 16-bits");
         index = idx;
-        READWRITE(REF(TransactionCompressor(tx)));
+        READWRITE(TransactionCompressor(tx));
     }
 };
 
diff --git a/src/coins.h b/src/coins.h
index c6850947e2..a73f016a31 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -69,7 +69,7 @@ public:
         ::Unserialize(s, VARINT(code));
         nHeight = code >> 1;
         fCoinBase = code & 1;
-        ::Unserialize(s, REF(CTxOutCompressor(out)));
+        ::Unserialize(s, CTxOutCompressor(out));
     }
 
     bool IsSpent() const {
diff --git a/src/compressor.h b/src/compressor.h
index ee26f4c533..6fcecd27e9 100644
--- a/src/compressor.h
+++ b/src/compressor.h
@@ -73,7 +73,7 @@ public:
         s >> VARINT(nSize);
         if (nSize < nSpecialScripts) {
             std::vector<unsigned char> vch(GetSpecialSize(nSize), 0x00);
-            s >> REF(CFlatData(vch));
+            s >> CFlatData(vch);
             Decompress(nSize, vch);
             return;
         }
@@ -84,7 +84,7 @@ public:
             s.ignore(nSize);
         } else {
             script.resize(nSize);
-            s >> REF(CFlatData(script));
+            s >> CFlatData(script);
         }
     }
 };
diff --git a/src/hash.h b/src/hash.h
index 35995a2d15..75353e0c0f 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -173,7 +173,7 @@ public:
     }
 
     template<typename T>
-    CHashVerifier<Source>& operator>>(T& obj)
+    CHashVerifier<Source>& operator>>(T&& obj)
     {
         // Unserialize from this stream
         ::Unserialize(*this, obj);
diff --git a/src/script/bitcoinconsensus.cpp b/src/script/bitcoinconsensus.cpp
index 7d3587e2c2..8cc44b675f 100644
--- a/src/script/bitcoinconsensus.cpp
+++ b/src/script/bitcoinconsensus.cpp
@@ -40,7 +40,7 @@ public:
     }
 
     template<typename T>
-    TxInputStream& operator>>(T& obj)
+    TxInputStream& operator>>(T&& obj)
     {
         ::Unserialize(*this, obj);
         return *this;
diff --git a/src/serialize.h b/src/serialize.h
index 862fe39e45..c454ba16b7 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -350,10 +350,10 @@ I ReadVarInt(Stream& is)
     }
 }
 
-#define FLATDATA(obj) REF(CFlatData((char*)&(obj), (char*)&(obj) + sizeof(obj)))
-#define VARINT(obj) REF(WrapVarInt(REF(obj)))
-#define COMPACTSIZE(obj) REF(CCompactSize(REF(obj)))
-#define LIMITED_STRING(obj,n) REF(LimitedString< n >(REF(obj)))
+#define FLATDATA(obj) CFlatData((char*)&(obj), (char*)&(obj) + sizeof(obj))
+#define VARINT(obj) WrapVarInt(REF(obj))
+#define COMPACTSIZE(obj) CCompactSize(REF(obj))
+#define LIMITED_STRING(obj,n) LimitedString< n >(REF(obj))
 
 /** 
  * Wrapper for serializing arrays and POD.
@@ -538,7 +538,7 @@ inline void Serialize(Stream& os, const T& a)
 }
 
 template<typename Stream, typename T>
-inline void Unserialize(Stream& is, T& a)
+inline void Unserialize(Stream& is, T&& a)
 {
     a.Unserialize(is);
 }
@@ -884,10 +884,10 @@ void SerializeMany(Stream& s)
 }
 
 template<typename Stream, typename Arg, typename... Args>
-void SerializeMany(Stream& s, Arg&& arg, Args&&... args)
+void SerializeMany(Stream& s, const Arg& arg, const Args&... args)
 {
-    ::Serialize(s, std::forward<Arg>(arg));
-    ::SerializeMany(s, std::forward<Args>(args)...);
+    ::Serialize(s, arg);
+    ::SerializeMany(s, args...);
 }
 
 template<typename Stream>
@@ -896,20 +896,20 @@ inline void UnserializeMany(Stream& s)
 }
 
 template<typename Stream, typename Arg, typename... Args>
-inline void UnserializeMany(Stream& s, Arg& arg, Args&... args)
+inline void UnserializeMany(Stream& s, Arg&& arg, Args&&... args)
 {
     ::Unserialize(s, arg);
     ::UnserializeMany(s, args...);
 }
 
 template<typename Stream, typename... Args>
-inline void SerReadWriteMany(Stream& s, CSerActionSerialize ser_action, Args&&... args)
+inline void SerReadWriteMany(Stream& s, CSerActionSerialize ser_action, const Args&... args)
 {
-    ::SerializeMany(s, std::forward<Args>(args)...);
+    ::SerializeMany(s, args...);
 }
 
 template<typename Stream, typename... Args>
-inline void SerReadWriteMany(Stream& s, CSerActionUnserialize ser_action, Args&... args)
+inline void SerReadWriteMany(Stream& s, CSerActionUnserialize ser_action, Args&&... args)
 {
     ::UnserializeMany(s, args...);
 }
diff --git a/src/streams.h b/src/streams.h
index 9f86c4a163..6ba4f103da 100644
--- a/src/streams.h
+++ b/src/streams.h
@@ -42,7 +42,7 @@ public:
     }
 
     template<typename T>
-    OverrideStream<Stream>& operator>>(T& obj)
+    OverrideStream<Stream>& operator>>(T&& obj)
     {
         // Unserialize from this stream
         ::Unserialize(*this, obj);
@@ -399,7 +399,7 @@ public:
     }
 
     template<typename T>
-    CDataStream& operator>>(T& obj)
+    CDataStream& operator>>(T&& obj)
     {
         // Unserialize from this stream
         ::Unserialize(*this, obj);
@@ -543,7 +543,7 @@ public:
     }
 
     template<typename T>
-    CAutoFile& operator>>(T& obj)
+    CAutoFile& operator>>(T&& obj)
     {
         // Unserialize from this stream
         if (!file)
@@ -686,7 +686,7 @@ public:
     }
 
     template<typename T>
-    CBufferedFile& operator>>(T& obj) {
+    CBufferedFile& operator>>(T&& obj) {
         // Unserialize from this stream
         ::Unserialize(*this, obj);
         return (*this);
diff --git a/src/txdb.cpp b/src/txdb.cpp
index 293d43c7b3..7a1d920117 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -348,7 +348,7 @@ public:
         vout.assign(vAvail.size(), CTxOut());
         for (unsigned int i = 0; i < vAvail.size(); i++) {
             if (vAvail[i])
-                ::Unserialize(s, REF(CTxOutCompressor(vout[i])));
+                ::Unserialize(s, CTxOutCompressor(vout[i]));
         }
         // coinbase height
         ::Unserialize(s, VARINT(nHeight));
diff --git a/src/undo.h b/src/undo.h
index 1f10c6652c..7aae034de2 100644
--- a/src/undo.h
+++ b/src/undo.h
@@ -54,7 +54,7 @@ public:
             int nVersionDummy;
             ::Unserialize(s, VARINT(nVersionDummy));
         }
-        ::Unserialize(s, REF(CTxOutCompressor(REF(txout->out))));
+        ::Unserialize(s, CTxOutCompressor(REF(txout->out)));
     }
 
     explicit TxInUndoDeserializer(Coin* coin) : txout(coin) {}
@@ -76,7 +76,7 @@ public:
         uint64_t count = vprevout.size();
         ::Serialize(s, COMPACTSIZE(REF(count)));
         for (const auto& prevout : vprevout) {
-            ::Serialize(s, REF(TxInUndoSerializer(&prevout)));
+            ::Serialize(s, TxInUndoSerializer(&prevout));
         }
     }
 
@@ -90,7 +90,7 @@ public:
         }
         vprevout.resize(count);
         for (auto& prevout : vprevout) {
-            ::Unserialize(s, REF(TxInUndoDeserializer(&prevout)));
+            ::Unserialize(s, TxInUndoDeserializer(&prevout));
         }
     }
 };