From 4de934b9b5b4be1bac8fe205f4ee9a79e772dc34 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sat, 18 Jan 2020 07:32:58 -0800
Subject: [PATCH] Convert compression.h to new serialization framework

---
 src/coins.h                   |  4 +--
 src/compressor.h              | 53 +++++++++++++----------------------
 src/test/fuzz/deserialize.cpp |  2 +-
 src/txdb.cpp                  |  2 +-
 src/undo.h                    |  4 +--
 5 files changed, 25 insertions(+), 40 deletions(-)

diff --git a/src/coins.h b/src/coins.h
index 68f759674506e..e71c8a47bcb9b 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -61,7 +61,7 @@ class Coin
         assert(!IsSpent());
         uint32_t code = nHeight * 2 + fCoinBase;
         ::Serialize(s, VARINT(code));
-        ::Serialize(s, CTxOutCompressor(REF(out)));
+        ::Serialize(s, Using<TxOutCompression>(out));
     }
 
     template<typename Stream>
@@ -70,7 +70,7 @@ class Coin
         ::Unserialize(s, VARINT(code));
         nHeight = code >> 1;
         fCoinBase = code & 1;
-        ::Unserialize(s, CTxOutCompressor(out));
+        ::Unserialize(s, Using<TxOutCompression>(out));
     }
 
     bool IsSpent() const {
diff --git a/src/compressor.h b/src/compressor.h
index c1eda503c8d82..7bb60d311e6b6 100644
--- a/src/compressor.h
+++ b/src/compressor.h
@@ -11,10 +11,6 @@
 #include <serialize.h>
 #include <span.h>
 
-class CKeyID;
-class CPubKey;
-class CScriptID;
-
 bool CompressScript(const CScript& script, std::vector<unsigned char> &out);
 unsigned int GetSpecialScriptSize(unsigned int nSize);
 bool DecompressScript(CScript& script, unsigned int nSize, const std::vector<unsigned char> &out);
@@ -33,9 +29,8 @@ uint64_t DecompressAmount(uint64_t nAmount);
  *  Other scripts up to 121 bytes require 1 byte + script length. Above
  *  that, scripts up to 16505 bytes require 2 bytes + script length.
  */
-class CScriptCompressor
+struct ScriptCompression
 {
-private:
     /**
      * make this static for now (there are only 6 special scripts defined)
      * this can potentially be extended together with a new nVersion for
@@ -44,12 +39,8 @@ class CScriptCompressor
      */
     static const unsigned int nSpecialScripts = 6;
 
-    CScript &script;
-public:
-    explicit CScriptCompressor(CScript &scriptIn) : script(scriptIn) { }
-
     template<typename Stream>
-    void Serialize(Stream &s) const {
+    void Ser(Stream &s, const CScript& script) {
         std::vector<unsigned char> compr;
         if (CompressScript(script, compr)) {
             s << MakeSpan(compr);
@@ -61,7 +52,7 @@ class CScriptCompressor
     }
 
     template<typename Stream>
-    void Unserialize(Stream &s) {
+    void Unser(Stream &s, CScript& script) {
         unsigned int nSize = 0;
         s >> VARINT(nSize);
         if (nSize < nSpecialScripts) {
@@ -82,30 +73,24 @@ class CScriptCompressor
     }
 };
 
-/** wrapper for CTxOut that provides a more compact serialization */
-class CTxOutCompressor
+struct AmountCompression
 {
-private:
-    CTxOut &txout;
-
-public:
-    explicit CTxOutCompressor(CTxOut &txoutIn) : txout(txoutIn) { }
-
-    ADD_SERIALIZE_METHODS;
-
-    template <typename Stream, typename Operation>
-    inline void SerializationOp(Stream& s, Operation ser_action) {
-        if (!ser_action.ForRead()) {
-            uint64_t nVal = CompressAmount(txout.nValue);
-            READWRITE(VARINT(nVal));
-        } else {
-            uint64_t nVal = 0;
-            READWRITE(VARINT(nVal));
-            txout.nValue = DecompressAmount(nVal);
-        }
-        CScriptCompressor cscript(REF(txout.scriptPubKey));
-        READWRITE(cscript);
+    template<typename Stream, typename I> void Ser(Stream& s, I val)
+    {
+        s << VARINT(CompressAmount(val));
+    }
+    template<typename Stream, typename I> void Unser(Stream& s, I& val)
+    {
+        uint64_t v;
+        s >> VARINT(v);
+        val = DecompressAmount(v);
     }
 };
 
+/** wrapper for CTxOut that provides a more compact serialization */
+struct TxOutCompression
+{
+    FORMATTER_METHODS(CTxOut, obj) { READWRITE(Using<AmountCompression>(obj.nValue), Using<ScriptCompression>(obj.scriptPubKey)); }
+};
+
 #endif // BITCOIN_COMPRESSOR_H
diff --git a/src/test/fuzz/deserialize.cpp b/src/test/fuzz/deserialize.cpp
index bd05283b785e3..f06f339b9d01d 100644
--- a/src/test/fuzz/deserialize.cpp
+++ b/src/test/fuzz/deserialize.cpp
@@ -206,7 +206,7 @@ void test_one_input(const std::vector<uint8_t>& buffer)
         DeserializeFromFuzzingInput(buffer, dbi);
 #elif TXOUTCOMPRESSOR_DESERIALIZE
         CTxOut to;
-        CTxOutCompressor toc(to);
+        auto toc = Using<TxOutCompression>(to);
         DeserializeFromFuzzingInput(buffer, toc);
 #elif BLOCKTRANSACTIONS_DESERIALIZE
         BlockTransactions bt;
diff --git a/src/txdb.cpp b/src/txdb.cpp
index 956825114951a..35bbdab00d635 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -336,7 +336,7 @@ class CCoins
         vout.assign(vAvail.size(), CTxOut());
         for (unsigned int i = 0; i < vAvail.size(); i++) {
             if (vAvail[i])
-                ::Unserialize(s, CTxOutCompressor(vout[i]));
+                ::Unserialize(s, Using<TxOutCompression>(vout[i]));
         }
         // coinbase height
         ::Unserialize(s, VARINT(nHeight, VarIntMode::NONNEGATIVE_SIGNED));
diff --git a/src/undo.h b/src/undo.h
index 3f50f4caad90e..2009c721ab132 100644
--- a/src/undo.h
+++ b/src/undo.h
@@ -32,7 +32,7 @@ class TxInUndoSerializer
             // Required to maintain compatibility with older undo format.
             ::Serialize(s, (unsigned char)0);
         }
-        ::Serialize(s, CTxOutCompressor(REF(txout->out)));
+        ::Serialize(s, Using<TxOutCompression>(REF(txout->out)));
     }
 
     explicit TxInUndoSerializer(const Coin* coin) : txout(coin) {}
@@ -56,7 +56,7 @@ class TxInUndoDeserializer
             unsigned int nVersionDummy;
             ::Unserialize(s, VARINT(nVersionDummy));
         }
-        ::Unserialize(s, CTxOutCompressor(REF(txout->out)));
+        ::Unserialize(s, Using<TxOutCompression>(REF(txout->out)));
     }
 
     explicit TxInUndoDeserializer(Coin* coin) : txout(coin) {}