Merge #12683: Fix more constness violations in serialization code

172f5fa738 Support deserializing into temporaries (Pieter Wuille)
2761bca997 Merge READWRITEMANY into READWRITE (Pieter Wuille)

Pull request description:

  This is another fragment of improvements from #10785.

  The current serialization code does not support serializing/deserializing from/to temporaries (like `s >> CFlatData(script)`). As a result, there are many invocations of the `REF` macro which in addition to changing the reference type also changes the constness. This is unnecessary in C++11 as we can use rvalue references now instead.

  The first commit is an extra simplification we can make that removes the duplication of code between `READWRITE` and `READWRITEMANY` (and related functions).

Tree-SHA512: babfa9cb268cc3bc39917e4f0a90e4651c33d85032161e16547a07f3b257b7ca7940e0cbfd69f09439d26fafbb1a6cf6359101043407e2c7aeececf7f20b6eed

10 files changed, 30 insertions, 56 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 dcc8d8691e..c454ba16b7 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -148,8 +148,7 @@ enum
     SER_GETHASH         = (1 << 2),
 };
 
-#define READWRITE(obj)      (::SerReadWrite(s, (obj), ser_action))
-#define READWRITEMANY(...)      (::SerReadWriteMany(s, ser_action, __VA_ARGS__))
+#define READWRITE(...)      (::SerReadWriteMany(s, ser_action, __VA_ARGS__))
 
 /** 
  * Implement three methods for serializable objects. These are actually wrappers over
@@ -351,10 +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.
@@ -539,7 +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);
 }
@@ -825,19 +824,6 @@ struct CSerActionUnserialize
     constexpr bool ForRead() const { return true; }
 };
 
-template<typename Stream, typename T>
-inline void SerReadWrite(Stream& s, const T& obj, CSerActionSerialize ser_action)
-{
-    ::Serialize(s, obj);
-}
-
-template<typename Stream, typename T>
-inline void SerReadWrite(Stream& s, T& obj, CSerActionUnserialize ser_action)
-{
-    ::Unserialize(s, obj);
-}
-
-
 
 
 
@@ -897,17 +883,11 @@ void SerializeMany(Stream& s)
 {
 }
 
-template<typename Stream, typename Arg>
-void SerializeMany(Stream& s, Arg&& arg)
-{
-    ::Serialize(s, std::forward<Arg>(arg));
-}
-
 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>
@@ -915,27 +895,21 @@ inline void UnserializeMany(Stream& s)
 {
 }
 
-template<typename Stream, typename Arg>
-inline void UnserializeMany(Stream& s, Arg& arg)
-{
-    ::Unserialize(s, arg);
-}
-
 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/test/serialize_tests.cpp b/src/test/serialize_tests.cpp
index 4595519435..42fd59380a 100644
--- a/src/test/serialize_tests.cpp
+++ b/src/test/serialize_tests.cpp
@@ -53,7 +53,7 @@ public:
 
     template <typename Stream, typename Operation>
     inline void SerializationOp(Stream& s, Operation ser_action) {
-        READWRITEMANY(intval, boolval, stringval, FLATDATA(charstrval), txval);
+        READWRITE(intval, boolval, stringval, FLATDATA(charstrval), txval);
     }
 };
 
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));
         }
     }
 };