partial merge #13815: Add [[nodiscard]] to all {Decode,Parse}[...](...) functions returning bool (#4035)

* Merge #13815: Explicitly ignore the return value of DecodeBase58(...)

579497e77a

* Merge #13815: Default to DEFAULT_BLOCK_MIN_TX_FEE if unable to parse arg

7c5bc2a523

* Merge #13815: Add NODISCARD to all {Decode,Parse}[...](...) functions returning bool.

9cc0230cfc

src/Makefile.am

@@ -117,6 +117,7 @@ BITCOIN_CORE_H = \
   addressindex.h \
   spentindex.h \
   addrman.h \
+  attributes.h \
   base58.h \
   batchedlogger.h \
   bech32.h \

src/attributes.h

@@ -0,0 +1,22 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_ATTRIBUTES_H
+#define BITCOIN_ATTRIBUTES_H
+
+#if defined(__has_cpp_attribute)
+#  if __has_cpp_attribute(nodiscard)
+#    define NODISCARD [[nodiscard]]
+#  endif
+#endif
+#ifndef NODISCARD
+#  if defined(_MSC_VER) && _MSC_VER >= 1700
+#    define NODISCARD _Check_return_
+#  else
+#    define NODISCARD __attribute__((warn_unused_result))
+#  endif
+#endif
+
+#endif // BITCOIN_ATTRIBUTES_H

src/base58.h

@@ -14,6 +14,8 @@
 #ifndef BITCOIN_BASE58_H
 #define BITCOIN_BASE58_H
 
+#include <attributes.h>
+
 #include <string>
 #include <vector>
 
@@ -33,13 +35,13 @@ std::string EncodeBase58(const std::vector<unsigned char>& vch);
  * return true if decoding is successful.
  * psz cannot be nullptr.
  */
-bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet);
+NODISCARD bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet);
 
 /**
  * Decode a base58-encoded string (str) into a byte vector (vchRet).
  * return true if decoding is successful.
  */
-bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet);
+NODISCARD bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet);
 
 /**
  * Encode a byte vector into a base58-encoded string, including checksum
@@ -50,12 +52,12 @@ std::string EncodeBase58Check(const std::vector<unsigned char>& vchIn);
  * Decode a base58-encoded string (psz) that includes a checksum into a byte
  * vector (vchRet), return true if decoding is successful
  */
-bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet);
+NODISCARD bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet);
 
 /**
  * Decode a base58-encoded string (str) that includes a checksum into a byte
  * vector (vchRet), return true if decoding is successful
  */
-bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet);
+NODISCARD bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet);
 
 #endif // BITCOIN_BASE58_H

src/bench/base58.cpp

@@ -49,7 +49,7 @@ static void Base58Decode(benchmark::State& state)
     const char* addr = "17VZNX1SN5NtKa8UQFxwQbFeFc3iqRYhem";
     std::vector<unsigned char> vch;
     while (state.KeepRunning()) {
-        DecodeBase58(addr, vch);
+        (void) DecodeBase58(addr, vch);
     }
 }
 

src/core_io.h

@@ -6,6 +6,7 @@
 #define BITCOIN_CORE_IO_H
 
 #include <amount.h>
+#include <attributes.h>
 
 #include <string>
 #include <vector>
@@ -22,8 +23,8 @@ struct CSpentIndexTxInfo;
 // core_read.cpp
 CScript ParseScript(const std::string& s);
 std::string ScriptToAsmStr(const CScript& script, const bool fAttemptSighashDecode = false);
-bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx);
-bool DecodeHexBlk(CBlock&, const std::string& strHexBlk);
+NODISCARD bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx);
+NODISCARD bool DecodeHexBlk(CBlock&, const std::string& strHexBlk);
 uint256 ParseHashStr(const std::string&, const std::string& strName);
 std::vector<unsigned char> ParseHexUV(const UniValue& v, const std::string& strName);
 

src/miner.cpp

@@ -83,9 +83,8 @@ static BlockAssembler::Options DefaultOptions(const CChainParams& params)
     if (gArgs.IsArgSet("-blockmaxsize")) {
         options.nBlockMaxSize = gArgs.GetArg("-blockmaxsize", DEFAULT_BLOCK_MAX_SIZE);
     }
-    if (gArgs.IsArgSet("-blockmintxfee")) {
-        CAmount n = 0;
-        ParseMoney(gArgs.GetArg("-blockmintxfee", ""), n);
+    CAmount n = 0;
+    if (gArgs.IsArgSet("-blockmintxfee") && ParseMoney(gArgs.GetArg("-blockmintxfee", ""), n)) {
         options.blockMinFeeRate = CFeeRate(n);
     } else {
         options.blockMinFeeRate = CFeeRate(DEFAULT_BLOCK_MIN_TX_FEE);

src/rest.cpp

@@ -3,19 +3,20 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <attributes.h>
 #include <chain.h>
 #include <chainparams.h>
 #include <core_io.h>
+#include <httpserver.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
-#include <validation.h>
-#include <httpserver.h>
 #include <rpc/blockchain.h>
 #include <rpc/server.h>
 #include <streams.h>
 #include <sync.h>
 #include <txmempool.h>
 #include <utilstrencodings.h>
+#include <validation.h>
 #include <version.h>
 
 #include <boost/algorithm/string.hpp>

src/util.h

@@ -15,6 +15,7 @@
 #include <config/dash-config.h>
 #endif
 
+#include <attributes.h>
 #include <compat.h>
 #include <fs.h>
 #include <logging.h>

src/utilmoneystr.h

@@ -9,16 +9,17 @@
 #ifndef BITCOIN_UTILMONEYSTR_H
 #define BITCOIN_UTILMONEYSTR_H
 
-#include <stdint.h>
-#include <string>
-
 #include <amount.h>
+#include <attributes.h>
+
+#include <cstdint>
+#include <string>
 
 /* Do not use these functions to represent or parse monetary amounts to or from
  * JSON but use AmountFromValue and ValueFromAmount for that.
  */
 std::string FormatMoney(const CAmount& n);
-bool ParseMoney(const std::string& str, CAmount& nRet);
-bool ParseMoney(const char* pszIn, CAmount& nRet);
+NODISCARD bool ParseMoney(const std::string& str, CAmount& nRet);
+NODISCARD bool ParseMoney(const char* pszIn, CAmount& nRet);
 
 #endif // BITCOIN_UTILMONEYSTR_H

src/utilstrencodings.cpp

@@ -261,7 +261,7 @@ std::string DecodeBase32(const std::string& str)
     return std::string((const char*)vchRet.data(), vchRet.size());
 }
 
-static bool ParsePrechecks(const std::string& str)
+NODISCARD static bool ParsePrechecks(const std::string& str)
 {
     if (str.empty()) // No empty string allowed
         return false;

src/utilstrencodings.h

@@ -9,7 +9,9 @@
 #ifndef BITCOIN_UTILSTRENCODINGS_H
 #define BITCOIN_UTILSTRENCODINGS_H
 
-#include <stdint.h>
+#include <attributes.h>
+
+#include <cstdint>
 #include <string>
 #include <vector>
 
@@ -76,35 +78,35 @@ constexpr bool IsDigit(char c)
  * @returns true if the entire string could be parsed as valid integer,
  *   false if not the entire string could be parsed or when overflow or underflow occurred.
  */
-bool ParseInt32(const std::string& str, int32_t *out);
+NODISCARD bool ParseInt32(const std::string& str, int32_t *out);
 
 /**
  * Convert string to signed 64-bit integer with strict parse error feedback.
  * @returns true if the entire string could be parsed as valid integer,
  *   false if not the entire string could be parsed or when overflow or underflow occurred.
  */
-bool ParseInt64(const std::string& str, int64_t *out);
+NODISCARD bool ParseInt64(const std::string& str, int64_t *out);
 
 /**
  * Convert decimal string to unsigned 32-bit integer with strict parse error feedback.
  * @returns true if the entire string could be parsed as valid integer,
  *   false if not the entire string could be parsed or when overflow or underflow occurred.
  */
-bool ParseUInt32(const std::string& str, uint32_t *out);
+NODISCARD bool ParseUInt32(const std::string& str, uint32_t *out);
 
 /**
  * Convert decimal string to unsigned 64-bit integer with strict parse error feedback.
  * @returns true if the entire string could be parsed as valid integer,
  *   false if not the entire string could be parsed or when overflow or underflow occurred.
  */
-bool ParseUInt64(const std::string& str, uint64_t *out);
+NODISCARD bool ParseUInt64(const std::string& str, uint64_t *out);
 
 /**
  * Convert string to double with strict parse error feedback.
  * @returns true if the entire string could be parsed as valid double,
  *   false if not the entire string could be parsed or when overflow or underflow occurred.
  */
-bool ParseDouble(const std::string& str, double *out);
+NODISCARD bool ParseDouble(const std::string& str, double *out);
 
 template<typename T>
 std::string HexStr(const T itbegin, const T itend, bool fSpaces=false)
@@ -157,7 +159,7 @@ bool TimingResistantEqual(const T& a, const T& b)
  * @returns true on success, false on error.
  * @note The result must be in the range (-10^18,10^18), otherwise an overflow error will trigger.
  */
-bool ParseFixedPoint(const std::string &val, int decimals, int64_t *amount_out);
+NODISCARD bool ParseFixedPoint(const std::string &val, int decimals, int64_t *amount_out);
 
 /** Convert from one power-of-2 number base to another. */
 template<int frombits, int tobits, bool pad, typename O, typename I>