From b1b2b238928e7be044ad62cf1b222464907ece2c Mon Sep 17 00:00:00 2001
From: Russell Yanofsky <russ@yanofsky.org>
Date: Tue, 17 Jul 2018 13:04:35 -0400
Subject: Remove use of CCoinsViewMemPool::GetCoin in wallet code

This commit does not change behavior.
---
 src/rpc/rawtransaction.cpp | 44 +++++++++++++++++++++-----------------------
 1 file changed, 21 insertions(+), 23 deletions(-)

(limited to 'src/rpc')

diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index d19afaa8a1..1336740292 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -11,6 +11,7 @@
 #include <core_io.h>
 #include <index/txindex.h>
 #include <init.h>
+#include <interfaces/chain.h>
 #include <key_io.h>
 #include <keystore.h>
 #include <merkleblock.h>
@@ -790,23 +791,20 @@ static UniValue combinerawtransaction(const JSONRPCRequest& request)
     return EncodeHexTx(CTransaction(mergedTx));
 }
 
+// TODO(https://github.com/bitcoin/bitcoin/pull/10973#discussion_r267084237):
+// This function is called from both wallet and node rpcs
+// (signrawtransactionwithwallet and signrawtransactionwithkey). It should be
+// moved to a util file so wallet code doesn't need to link against node code.
+// Also the dependency on interfaces::Chain should be removed, so
+// signrawtransactionwithkey doesn't need access to a Chain instance.
 UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, const UniValue& prevTxsUnival, CBasicKeyStore *keystore, bool is_temp_keystore, const UniValue& hashType)
 {
     // Fetch previous transactions (inputs):
-    CCoinsView viewDummy;
-    CCoinsViewCache view(&viewDummy);
-    {
-        LOCK2(cs_main, mempool.cs);
-        CCoinsViewCache &viewChain = *pcoinsTip;
-        CCoinsViewMemPool viewMempool(&viewChain, mempool);
-        view.SetBackend(viewMempool); // temporarily switch cache backend to db+mempool view
-
-        for (const CTxIn& txin : mtx.vin) {
-            view.AccessCoin(txin.prevout); // Load entries from viewChain into view; can fail.
-        }
-
-        view.SetBackend(viewDummy); // switch back to avoid locking mempool for too long
+    std::map<COutPoint, Coin> coins;
+    for (const CTxIn& txin : mtx.vin) {
+        coins[txin.prevout]; // Create empty map entry keyed by prevout.
     }
+    chain.findCoins(coins);
 
     // Add previous txouts given in the RPC call:
     if (!prevTxsUnival.isNull()) {
@@ -838,10 +836,10 @@ UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, con
             CScript scriptPubKey(pkData.begin(), pkData.end());
 
             {
-                const Coin& coin = view.AccessCoin(out);
-                if (!coin.IsSpent() && coin.out.scriptPubKey != scriptPubKey) {
+                auto coin = coins.find(out);
+                if (coin != coins.end() && !coin->second.IsSpent() && coin->second.out.scriptPubKey != scriptPubKey) {
                     std::string err("Previous output scriptPubKey mismatch:\n");
-                    err = err + ScriptToAsmStr(coin.out.scriptPubKey) + "\nvs:\n"+
+                    err = err + ScriptToAsmStr(coin->second.out.scriptPubKey) + "\nvs:\n"+
                         ScriptToAsmStr(scriptPubKey);
                     throw JSONRPCError(RPC_DESERIALIZATION_ERROR, err);
                 }
@@ -852,7 +850,7 @@ UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, con
                     newcoin.out.nValue = AmountFromValue(find_value(prevOut, "amount"));
                 }
                 newcoin.nHeight = 1;
-                view.AddCoin(out, std::move(newcoin), true);
+                coins[out] = std::move(newcoin);
             }
 
             // if redeemScript and private keys were given, add redeemScript to the keystore so it can be signed
@@ -896,15 +894,15 @@ UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, con
     // Sign what we can:
     for (unsigned int i = 0; i < mtx.vin.size(); i++) {
         CTxIn& txin = mtx.vin[i];
-        const Coin& coin = view.AccessCoin(txin.prevout);
-        if (coin.IsSpent()) {
+        auto coin = coins.find(txin.prevout);
+        if (coin == coins.end() || coin->second.IsSpent()) {
             TxInErrorToJSON(txin, vErrors, "Input not found or already spent");
             continue;
         }
-        const CScript& prevPubKey = coin.out.scriptPubKey;
-        const CAmount& amount = coin.out.nValue;
+        const CScript& prevPubKey = coin->second.out.scriptPubKey;
+        const CAmount& amount = coin->second.out.nValue;
 
-        SignatureData sigdata = DataFromTransaction(mtx, i, coin.out);
+        SignatureData sigdata = DataFromTransaction(mtx, i, coin->second.out);
         // Only sign SIGHASH_SINGLE if there's a corresponding output:
         if (!fHashSingle || (i < mtx.vout.size())) {
             ProduceSignature(*keystore, MutableTransactionSignatureCreator(&mtx, i, amount, nHashType), prevPubKey, sigdata);
@@ -914,7 +912,7 @@ UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, con
 
         // amount must be specified for valid segwit signature
         if (amount == MAX_MONEY && !txin.scriptWitness.IsNull()) {
-            throw JSONRPCError(RPC_TYPE_ERROR, strprintf("Missing amount for %s", coin.out.ToString()));
+            throw JSONRPCError(RPC_TYPE_ERROR, strprintf("Missing amount for %s", coin->second.out.ToString()));
         }
 
         ScriptError serror = SCRIPT_ERR_OK;
-- 
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