text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2016 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <keystore.h>
  
  #include <key.h>
  #include <pubkey.h>
  #include <util.h>
  
  void CBasicKeyStore::ImplicitlyLearnRelatedKeyScripts(const CPubKey &pubkey) {
      AssertLockHeld(cs_KeyStore);
      CKeyID key_id = pubkey.GetID();
      // We must actually know about this key already.
      assert(HaveKey(key_id) || mapWatchKeys.count(key_id));
      // This adds the redeemscripts necessary to detect alternative outputs using
      // the same keys. Also note that having superfluous scripts in the keystore
      // never hurts. They're only used to guide recursion in signing and IsMine
      // logic - if a script is present but we can't do anything with it, it has
      // no effect. "Implicitly" refers to fact that scripts are derived
      // automatically from existing keys, and are present in memory, even without
      // being explicitly loaded (e.g. from a file).
  
      // Right now there are none so do nothing.
  }
  
  bool CBasicKeyStore::GetPubKey(const CKeyID &address,
                                 CPubKey &vchPubKeyOut) const {
      CKey key;
      if (!GetKey(address, key)) {
          LOCK(cs_KeyStore);
          WatchKeyMap::const_iterator it = mapWatchKeys.find(address);
          if (it != mapWatchKeys.end()) {
              vchPubKeyOut = it->second;
              return true;
          }
          return false;
      }
      vchPubKeyOut = key.GetPubKey();
      return true;
  }
  
  bool CBasicKeyStore::AddKeyPubKey(const CKey &key, const CPubKey &pubkey) {
      LOCK(cs_KeyStore);
      mapKeys[pubkey.GetID()] = key;
      ImplicitlyLearnRelatedKeyScripts(pubkey);
      return true;
  }
  
  bool CBasicKeyStore::HaveKey(const CKeyID &address) const {
      LOCK(cs_KeyStore);
      return mapKeys.count(address) > 0;
  }
  
  std::set<CKeyID> CBasicKeyStore::GetKeys() const {
      LOCK(cs_KeyStore);
      std::set<CKeyID> set_address;
      for (const auto &mi : mapKeys) {
          set_address.insert(mi.first);
      }
      return set_address;
  }
  
  bool CBasicKeyStore::GetKey(const CKeyID &address, CKey &keyOut) const {
      LOCK(cs_KeyStore);
      KeyMap::const_iterator mi = mapKeys.find(address);
      if (mi != mapKeys.end()) {
          keyOut = mi->second;
          return true;
      }
      return false;
  }
  
  bool CBasicKeyStore::AddCScript(const CScript &redeemScript) {
      if (redeemScript.size() > MAX_SCRIPT_ELEMENT_SIZE) {
          return error("CBasicKeyStore::AddCScript(): redeemScripts > %i bytes "
                       "are invalid",
                       MAX_SCRIPT_ELEMENT_SIZE);
      }
  
      LOCK(cs_KeyStore);
      mapScripts[CScriptID(redeemScript)] = redeemScript;
      return true;
  }
  
  bool CBasicKeyStore::HaveCScript(const CScriptID &hash) const {
      LOCK(cs_KeyStore);
      return mapScripts.count(hash) > 0;
  }
  
  std::set<CScriptID> CBasicKeyStore::GetCScripts() const {
      LOCK(cs_KeyStore);
      std::set<CScriptID> set_script;
      for (const auto &mi : mapScripts) {
          set_script.insert(mi.first);
      }
      return set_script;
  }
  
  bool CBasicKeyStore::GetCScript(const CScriptID &hash,
                                  CScript &redeemScriptOut) const {
      LOCK(cs_KeyStore);
      ScriptMap::const_iterator mi = mapScripts.find(hash);
      if (mi != mapScripts.end()) {
          redeemScriptOut = (*mi).second;
          return true;
      }
      return false;
  }
  
  static bool ExtractPubKey(const CScript &dest, CPubKey &pubKeyOut) {
      // TODO: Use Solver to extract this?
      CScript::const_iterator pc = dest.begin();
      opcodetype opcode;
      std::vector<uint8_t> vch;
      if (!dest.GetOp(pc, opcode, vch) || !CPubKey::ValidSize(vch)) {
          return false;
      }
      pubKeyOut = CPubKey(vch);
      if (!pubKeyOut.IsFullyValid()) {
          return false;
      }
      if (!dest.GetOp(pc, opcode, vch) || opcode != OP_CHECKSIG ||
          dest.GetOp(pc, opcode, vch)) {
          return false;
      }
      return true;
  }
  
  bool CBasicKeyStore::AddWatchOnly(const CScript &dest) {
      LOCK(cs_KeyStore);
      setWatchOnly.insert(dest);
      CPubKey pubKey;
      if (ExtractPubKey(dest, pubKey)) {
          mapWatchKeys[pubKey.GetID()] = pubKey;
          ImplicitlyLearnRelatedKeyScripts(pubKey);
      }
      return true;
  }
  
  bool CBasicKeyStore::RemoveWatchOnly(const CScript &dest) {
      LOCK(cs_KeyStore);
      setWatchOnly.erase(dest);
      CPubKey pubKey;
      if (ExtractPubKey(dest, pubKey)) {
          mapWatchKeys.erase(pubKey.GetID());
      }
      // Related CScripts are not removed; having superfluous scripts around is
      // harmless (see comment in ImplicitlyLearnRelatedKeyScripts).
      return true;
  }
  
  bool CBasicKeyStore::HaveWatchOnly(const CScript &dest) const {
      LOCK(cs_KeyStore);
      return setWatchOnly.count(dest) > 0;
  }
  
  bool CBasicKeyStore::HaveWatchOnly() const {
      LOCK(cs_KeyStore);
      return (!setWatchOnly.empty());
  }
  
  CKeyID GetKeyForDestination(const CKeyStore &store,
                              const CTxDestination &dest) {
      // Only supports destinations which map to single public keys, i.e. P2PKH.
      if (auto id = boost::get<CKeyID>(&dest)) {
          return *id;
      }
      return CKeyID();
  }
  