Merge #14821: Replace CAffectedKeysVisitor with descriptor based logic

0e75f44a0 Replace CAffectedKeysVisitor with descriptor based logic (Pieter Wuille)

Pull request description:

  It seems we don't need a custom visitor pattern anymore to find what keys are affected by a script. Instead, infer the descriptor, and see which keys it expands to.

Tree-SHA512: 8a52f61fb74e8ebfd8d02e759629e423ced6bd7d9a9ee7c4bdd2cca8465bc27b951cc69c8d835244a611ba55c6d22f83b81acef05487cb988c88c0951b797699

src/wallet/wallet.cpp

@@ -22,6 +22,7 @@
 #include <policy/rbf.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
+#include <script/descriptor.h>
 #include <script/script.h>
 #include <shutdown.h>
 #include <timedata.h>
@@ -104,67 +105,17 @@ std::string COutput::ToString() const
     return strprintf("COutput(%s, %d, %d) [%s]", tx->GetHash().ToString(), i, nDepth, FormatMoney(tx->tx->vout[i].nValue));
 }
 
-/** A class to identify which pubkeys a script and a keystore have in common. */
-class CAffectedKeysVisitor : public boost::static_visitor<void> {
-private:
-    const CKeyStore &keystore;
-    std::vector<CKeyID> &vKeys;
-
-public:
-    /**
-     * @param[in] keystoreIn The CKeyStore that is queried for the presence of a pubkey.
-     * @param[out] vKeysIn A vector to which a script's pubkey identifiers are appended if they are in the keystore.
-     */
-    CAffectedKeysVisitor(const CKeyStore &keystoreIn, std::vector<CKeyID> &vKeysIn) : keystore(keystoreIn), vKeys(vKeysIn) {}
-
-    /**
-     * Apply the visitor to each destination in a script, recursively to the redeemscript
-     * in the case of p2sh destinations.
-     * @param[in] script The CScript from which destinations are extracted.
-     * @post Any CKeyIDs that script and keystore have in common are appended to the visitor's vKeys.
-     */
-    void Process(const CScript &script) {
-        txnouttype type;
-        std::vector<CTxDestination> vDest;
-        int nRequired;
-        if (ExtractDestinations(script, type, vDest, nRequired)) {
-            for (const CTxDestination &dest : vDest)
-                boost::apply_visitor(*this, dest);
-        }
-    }
-
-    void operator()(const CKeyID &keyId) {
-        if (keystore.HaveKey(keyId))
-            vKeys.push_back(keyId);
-    }
-
-    void operator()(const CScriptID &scriptId) {
-        CScript script;
-        if (keystore.GetCScript(scriptId, script))
-            Process(script);
-    }
-
-    void operator()(const WitnessV0ScriptHash& scriptID)
-    {
-        CScriptID id;
-        CRIPEMD160().Write(scriptID.begin(), 32).Finalize(id.begin());
-        CScript script;
-        if (keystore.GetCScript(id, script)) {
-            Process(script);
-        }
-    }
-
-    void operator()(const WitnessV0KeyHash& keyid)
-    {
-        CKeyID id(keyid);
-        if (keystore.HaveKey(id)) {
-            vKeys.push_back(id);
-        }
+std::vector<CKeyID> GetAffectedKeys(const CScript& spk, const SigningProvider& provider)
+{
+    std::vector<CScript> dummy;
+    FlatSigningProvider out;
+    InferDescriptor(spk, provider)->Expand(0, DUMMY_SIGNING_PROVIDER, dummy, out);
+    std::vector<CKeyID> ret;
+    for (const auto& entry : out.pubkeys) {
+        ret.push_back(entry.first);
     }
-
-    template<typename X>
-    void operator()(const X &none) {}
-};
+    return ret;
+}
 
 const CWalletTx* CWallet::GetWalletTx(const uint256& hash) const
 {
@@ -977,9 +928,7 @@ bool CWallet::AddToWalletIfInvolvingMe(const CTransactionRef& ptx, const CBlockI
             // loop though all outputs
             for (const CTxOut& txout: tx.vout) {
                 // extract addresses and check if they match with an unused keypool key
-                std::vector<CKeyID> vAffected;
-                CAffectedKeysVisitor(*this, vAffected).Process(txout.scriptPubKey);
-                for (const CKeyID &keyid : vAffected) {
+                for (const auto& keyid : GetAffectedKeys(txout.scriptPubKey, *this)) {
                     std::map<CKeyID, int64_t>::const_iterator mi = m_pool_key_to_index.find(keyid);
                     if (mi != m_pool_key_to_index.end()) {
                         WalletLogPrintf("%s: Detected a used keypool key, mark all keypool key up to this key as used\n", __func__);
@@ -3711,7 +3660,6 @@ void CWallet::GetKeyBirthTimes(interfaces::Chain::Lock& locked_chain, std::map<C
         return;
 
     // find first block that affects those keys, if there are any left
-    std::vector<CKeyID> vAffected;
     for (const auto& entry : mapWallet) {
         // iterate over all wallet transactions...
         const CWalletTx &wtx = entry.second;
@@ -3721,14 +3669,12 @@ void CWallet::GetKeyBirthTimes(interfaces::Chain::Lock& locked_chain, std::map<C
             int nHeight = pindex->nHeight;
             for (const CTxOut &txout : wtx.tx->vout) {
                 // iterate over all their outputs
-                CAffectedKeysVisitor(*this, vAffected).Process(txout.scriptPubKey);
-                for (const CKeyID &keyid : vAffected) {
+                for (const auto &keyid : GetAffectedKeys(txout.scriptPubKey, *this)) {
                     // ... and all their affected keys
                     std::map<CKeyID, CBlockIndex*>::iterator rit = mapKeyFirstBlock.find(keyid);
                     if (rit != mapKeyFirstBlock.end() && nHeight < rit->second->nHeight)
                         rit->second = pindex;
                 }
-                vAffected.clear();
             }
         }
     }