rpc: minimize locking in getrawtransaction

since there is i/o that can happen when retrieving extended input
and output information, limiting the duration of the lock in getrawtransaction
can help improve concurrency

Author: Braydon Fuller

src/rpcrawtransaction.cpp

@@ -59,8 +59,10 @@ void ScriptPubKeyToJSON(const CScript& scriptPubKey, UniValue& out, bool fInclud
     out.push_back(Pair("addresses", a));
 }
 
-void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry)
+void TxToJSONExpanded(const CTransaction& tx, const uint256 hashBlock, UniValue& entry,
+                      int nHeight = 0, int nConfirmations = 0, int nBlockTime = 0)
 {
+
     uint256 txid = tx.GetHash();
     entry.push_back(Pair("txid", txid.GetHex()));
     entry.push_back(Pair("size", (int)::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION)));
@@ -121,6 +123,63 @@ void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry)
     }
     entry.push_back(Pair("vout", vout));
 
+    if (!hashBlock.IsNull()) {
+        entry.push_back(Pair("blockhash", hashBlock.GetHex()));
+
+        if (nConfirmations > 0) {
+            entry.push_back(Pair("height", nHeight));
+            entry.push_back(Pair("confirmations", nConfirmations));
+            entry.push_back(Pair("time", nBlockTime));
+            entry.push_back(Pair("blocktime", nBlockTime));
+        } else {
+            entry.push_back(Pair("height", -1));
+            entry.push_back(Pair("confirmations", 0));
+        }
+    }
+
+}
+
+void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry)
+{
+
+    uint256 txid = tx.GetHash();
+    entry.push_back(Pair("txid", txid.GetHex()));
+    entry.push_back(Pair("size", (int)::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION)));
+    entry.push_back(Pair("version", tx.nVersion));
+    entry.push_back(Pair("locktime", (int64_t)tx.nLockTime));
+
+    UniValue vin(UniValue::VARR);
+    BOOST_FOREACH(const CTxIn& txin, tx.vin) {
+        UniValue in(UniValue::VOBJ);
+        if (tx.IsCoinBase())
+            in.push_back(Pair("coinbase", HexStr(txin.scriptSig.begin(), txin.scriptSig.end())));
+        else {
+            in.push_back(Pair("txid", txin.prevout.hash.GetHex()));
+            in.push_back(Pair("vout", (int64_t)txin.prevout.n));
+            UniValue o(UniValue::VOBJ);
+            o.push_back(Pair("asm", ScriptToAsmStr(txin.scriptSig, true)));
+            o.push_back(Pair("hex", HexStr(txin.scriptSig.begin(), txin.scriptSig.end())));
+            in.push_back(Pair("scriptSig", o));
+        }
+        in.push_back(Pair("sequence", (int64_t)txin.nSequence));
+        vin.push_back(in);
+    }
+    entry.push_back(Pair("vin", vin));
+
+    UniValue vout(UniValue::VARR);
+    for (unsigned int i = 0; i < tx.vout.size(); i++) {
+        const CTxOut& txout = tx.vout[i];
+        UniValue out(UniValue::VOBJ);
+        out.push_back(Pair("value", ValueFromAmount(txout.nValue)));
+        out.push_back(Pair("valueSat", txout.nValue));
+        out.push_back(Pair("n", (int64_t)i));
+        UniValue o(UniValue::VOBJ);
+        ScriptPubKeyToJSON(txout.scriptPubKey, o, true);
+        out.push_back(Pair("scriptPubKey", o));
+        vout.push_back(out);
+    }
+    entry.push_back(Pair("vout", vout));
+
     if (!hashBlock.IsNull()) {
         entry.push_back(Pair("blockhash", hashBlock.GetHex()));
         BlockMap::iterator mi = mapBlockIndex.find(hashBlock);
@@ -206,18 +265,38 @@ UniValue getrawtransaction(const UniValue& params, bool fHelp)
             + HelpExampleRpc("getrawtransaction", "\"mytxid\", 1")
         );
 
-    LOCK(cs_main);
-
     uint256 hash = ParseHashV(params[0], "parameter 1");
 
     bool fVerbose = false;
     if (params.size() > 1)
         fVerbose = (params[1].get_int() != 0);
 
     CTransaction tx;
+
     uint256 hashBlock;
-    if (!GetTransaction(hash, tx, Params().GetConsensus(), hashBlock, true))
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "No information available about transaction");
+    int nHeight = 0;
+    int nConfirmations = 0;
+    int nBlockTime = 0;
+
+    {
+        LOCK(cs_main);
+        if (!GetTransaction(hash, tx, Params().GetConsensus(), hashBlock, true))
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "No information available about transaction");
+
+        BlockMap::iterator mi = mapBlockIndex.find(hashBlock);
+        if (mi != mapBlockIndex.end() && (*mi).second) {
+            CBlockIndex* pindex = (*mi).second;
+            if (chainActive.Contains(pindex)) {
+                nHeight = pindex->nHeight;
+                nConfirmations = 1 + chainActive.Height() - pindex->nHeight;
+                nBlockTime = pindex->GetBlockTime();
+            } else {
+                nHeight = -1;
+                nConfirmations = 0;
+                nBlockTime = pindex->GetBlockTime();
+            }
+        }
+    }
 
     string strHex = EncodeHexTx(tx);
 
@@ -226,7 +305,8 @@ UniValue getrawtransaction(const UniValue& params, bool fHelp)
 
     UniValue result(UniValue::VOBJ);
     result.push_back(Pair("hex", strHex));
-    TxToJSON(tx, hashBlock, result);
+    TxToJSONExpanded(tx, hashBlock, result, nHeight, nConfirmations, nBlockTime);
+
     return result;
 }