external_signer: use const where appropriate

Author: fanquake

src/external_signer.cpp

@@ -14,14 +14,14 @@
 
 #ifdef ENABLE_EXTERNAL_SIGNER
 
-ExternalSigner::ExternalSigner(const std::string& command, const std::string& fingerprint, std::string chain, std::string name): m_command(command), m_fingerprint(fingerprint), m_chain(chain), m_name(name) {}
+ExternalSigner::ExternalSigner(const std::string& command, const std::string& fingerprint, const std::string chain, const std::string name): m_command(command), m_fingerprint(fingerprint), m_chain(chain), m_name(name) {}
 
 const std::string ExternalSigner::NetworkArg() const
 {
     return " --chain " + m_chain;
 }
 
-bool ExternalSigner::Enumerate(const std::string& command, std::vector<ExternalSigner>& signers, std::string chain)
+bool ExternalSigner::Enumerate(const std::string& command, std::vector<ExternalSigner>& signers, const std::string chain)
 {
     // Call <command> enumerate
     const UniValue result = RunCommandParseJSON(command + " enumerate");
@@ -42,10 +42,10 @@ bool ExternalSigner::Enumerate(const std::string& command, std::vector<ExternalS
         if (fingerprint.isNull()) {
             throw ExternalSignerException(strprintf("'%s' received invalid response, missing signer fingerprint", command));
         }
-        std::string fingerprintStr = fingerprint.get_str();
+        const std::string fingerprintStr = fingerprint.get_str();
         // Skip duplicate signer
         bool duplicate = false;
-        for (ExternalSigner signer : signers) {
+        for (const ExternalSigner& signer : signers) {
             if (signer.m_fingerprint.compare(fingerprintStr) == 0) duplicate = true;
         }
         if (duplicate) break;
@@ -64,7 +64,7 @@ UniValue ExternalSigner::DisplayAddress(const std::string& descriptor) const
     return RunCommandParseJSON(m_command + " --fingerprint \"" + m_fingerprint + "\"" + NetworkArg() + " displayaddress --desc \"" + descriptor + "\"");
 }
 
-UniValue ExternalSigner::GetDescriptors(int account)
+UniValue ExternalSigner::GetDescriptors(const int account)
 {
     return RunCommandParseJSON(m_command + " --fingerprint \"" + m_fingerprint + "\"" + NetworkArg() + " getdescriptors --account " + strprintf("%d", account));
 }
@@ -79,7 +79,7 @@ bool ExternalSigner::SignTransaction(PartiallySignedTransaction& psbtx, std::str
     bool match = false;
     for (unsigned int i = 0; i < psbtx.inputs.size(); ++i) {
         const PSBTInput& input = psbtx.inputs[i];
-        for (auto entry : input.hd_keypaths) {
+        for (const auto& entry : input.hd_keypaths) {
             if (m_fingerprint == strprintf("%08x", ReadBE32(entry.second.fingerprint))) match = true;
         }
     }
@@ -89,8 +89,8 @@ bool ExternalSigner::SignTransaction(PartiallySignedTransaction& psbtx, std::str
         return false;
     }
 
-    std::string command = m_command + " --stdin --fingerprint \"" + m_fingerprint + "\"" + NetworkArg();
-    std::string stdinStr = "signtx \"" + EncodeBase64(ssTx.str()) + "\"";
+    const std::string command = m_command + " --stdin --fingerprint \"" + m_fingerprint + "\"" + NetworkArg();
+    const std::string stdinStr = "signtx \"" + EncodeBase64(ssTx.str()) + "\"";
 
     const UniValue signer_result = RunCommandParseJSON(command, stdinStr);
 

src/external_signer.h

@@ -34,7 +34,7 @@ class ExternalSigner
     //! @param[in] fingerprint  master key fingerprint of the signer
     //! @param[in] chain        "main", "test", "regtest" or "signet"
     //! @param[in] name         device name
-    ExternalSigner(const std::string& command, const std::string& fingerprint, std::string chain, std::string name);
+    ExternalSigner(const std::string& command, const std::string& fingerprint, const std::string chain, const std::string name);
 
     //! Master key fingerprint of the signer
     std::string m_fingerprint;
@@ -52,7 +52,7 @@ class ExternalSigner
     //! @param[in,out] signers  vector to which new signers (with a unique master key fingerprint) are added
     //! @param chain            "main", "test", "regtest" or "signet"
     //! @returns success
-    static bool Enumerate(const std::string& command, std::vector<ExternalSigner>& signers, std::string chain);
+    static bool Enumerate(const std::string& command, std::vector<ExternalSigner>& signers, const std::string chain);
 
     //! Display address on the device. Calls `<command> displayaddress --desc <descriptor>`.
     //! @param[in] descriptor Descriptor specifying which address to display.
@@ -63,7 +63,7 @@ class ExternalSigner
     //! Calls `<command> getdescriptors --account <account>`
     //! @param[in] account  which BIP32 account to use (e.g. `m/44'/0'/account'`)
     //! @returns see doc/external-signer.md
-    UniValue GetDescriptors(int account);
+    UniValue GetDescriptors(const int account);
 
     //! Sign PartiallySignedTransaction on the device.
     //! Calls `<command> signtransaction` and passes the PSBT via stdin.

src/rpc/external_signer.cpp

@@ -38,12 +38,12 @@ static RPCHelpMan enumeratesigners()
         {
             const std::string command = gArgs.GetArg("-signer", "");
             if (command == "") throw JSONRPCError(RPC_MISC_ERROR, "Error: restart bitcoind with -signer=<cmd>");
-            std::string chain = gArgs.GetChainName();
+            const std::string chain = gArgs.GetChainName();
             UniValue signers_res = UniValue::VARR;
             try {
                 std::vector<ExternalSigner> signers;
                 ExternalSigner::Enumerate(command, signers, chain);
-                for (ExternalSigner signer : signers) {
+                for (const ExternalSigner& signer : signers) {
                     UniValue signer_res = UniValue::VOBJ;
                     signer_res.pushKV("fingerprint", signer.m_fingerprint);
                     signer_res.pushKV("name", signer.m_name);