From a79342479f577013f2fd2573fb32585d6f4981b3 Mon Sep 17 00:00:00 2001
From: Jeff Garzik <jgarzik@bitpay.com>
Date: Mon, 24 Jun 2013 15:09:50 -0400
Subject: Relay OP_RETURN data TxOut as standard transaction type

---
 src/script.cpp | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

(limited to 'src/script.cpp')

diff --git a/src/script.cpp b/src/script.cpp
index 0fe2953548..858743f887 100644
--- a/src/script.cpp
+++ b/src/script.cpp
@@ -79,6 +79,7 @@ const char* GetTxnOutputType(txnouttype t)
     case TX_PUBKEYHASH: return "pubkeyhash";
     case TX_SCRIPTHASH: return "scripthash";
     case TX_MULTISIG: return "multisig";
+    case TX_NULL_DATA: return "nulldata";
     }
     return NULL;
 }
@@ -220,6 +221,7 @@ const char* GetOpName(opcodetype opcode)
     // template matching params
     case OP_PUBKEYHASH             : return "OP_PUBKEYHASH";
     case OP_PUBKEY                 : return "OP_PUBKEY";
+    case OP_SMALLDATA              : return "OP_SMALLDATA";
 
     case OP_INVALIDOPCODE          : return "OP_INVALIDOPCODE";
     default:
@@ -1148,6 +1150,9 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsi
 
         // Sender provides N pubkeys, receivers provides M signatures
         mTemplates.insert(make_pair(TX_MULTISIG, CScript() << OP_SMALLINTEGER << OP_PUBKEYS << OP_SMALLINTEGER << OP_CHECKMULTISIG));
+
+        // Empty, provably prunable, data-carrying output
+        mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN << OP_SMALLDATA));
     }
 
     // Shortcut for pay-to-script-hash, which are more constrained than the other types:
@@ -1232,6 +1237,12 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsi
                 else
                     break;
             }
+            else if (opcode2 == OP_SMALLDATA)
+            {
+                // small pushdata, <= 80 bytes
+                if (vch1.size() > 80)
+                    break;
+            }
             else if (opcode1 != opcode2 || vch1 != vch2)
             {
                 // Others must match exactly
@@ -1294,6 +1305,7 @@ bool Solver(const CKeyStore& keystore, const CScript& scriptPubKey, uint256 hash
     switch (whichTypeRet)
     {
     case TX_NONSTANDARD:
+    case TX_NULL_DATA:
         return false;
     case TX_PUBKEY:
         keyID = CPubKey(vSolutions[0]).GetID();
@@ -1325,6 +1337,8 @@ int ScriptSigArgsExpected(txnouttype t, const std::vector<std::vector<unsigned c
     {
     case TX_NONSTANDARD:
         return -1;
+    case TX_NULL_DATA:
+        return 1;
     case TX_PUBKEY:
         return 1;
     case TX_PUBKEYHASH:
@@ -1339,10 +1353,9 @@ int ScriptSigArgsExpected(txnouttype t, const std::vector<std::vector<unsigned c
     return -1;
 }
 
-bool IsStandard(const CScript& scriptPubKey)
+bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType)
 {
     vector<valtype> vSolutions;
-    txnouttype whichType;
     if (!Solver(scriptPubKey, whichType, vSolutions))
         return false;
 
@@ -1401,6 +1414,7 @@ bool IsMine(const CKeyStore &keystore, const CScript& scriptPubKey)
     switch (whichType)
     {
     case TX_NONSTANDARD:
+    case TX_NULL_DATA:
         return false;
     case TX_PUBKEY:
         keyID = CPubKey(vSolutions[0]).GetID();
@@ -1462,6 +1476,8 @@ bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, vecto
     vector<valtype> vSolutions;
     if (!Solver(scriptPubKey, typeRet, vSolutions))
         return false;
+    if (typeRet == TX_NULL_DATA)
+        return true;
 
     if (typeRet == TX_MULTISIG)
     {
@@ -1677,6 +1693,7 @@ static CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo,
     switch (txType)
     {
     case TX_NONSTANDARD:
+    case TX_NULL_DATA:
         // Don't know anything about this, assume bigger one is correct:
         if (sigs1.size() >= sigs2.size())
             return PushAll(sigs1);
-- 
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