14 files changed, 360 insertions, 153 deletions

diff --git a/src/util/asmap.cpp b/src/util/asmap.cpp
index bd77d74218..bacc3690a2 100644
--- a/src/util/asmap.cpp
+++ b/src/util/asmap.cpp
@@ -93,8 +93,7 @@ uint32_t Interpret(const std::vector<bool> &asmap, const std::vector<bool> &ip)
             jump = DecodeJump(pos, endpos);
             if (jump == INVALID) break; // Jump offset straddles EOF
             if (bits == 0) break; // No input bits left
-            if (pos + jump < pos) break; // overflow
-            if (pos + jump >= endpos) break; // Jumping past EOF
+            if (int64_t{jump} >= int64_t{endpos - pos}) break; // Jumping past EOF
             if (ip[ip.size() - bits]) {
                 pos += jump;
             }
@@ -156,8 +155,7 @@ bool SanityCheckASMap(const std::vector<bool>& asmap, int bits)
         } else if (opcode == Instruction::JUMP) {
             uint32_t jump = DecodeJump(pos, endpos);
             if (jump == INVALID) return false; // Jump offset straddles EOF
-            if (pos + jump < pos) return false; // overflow
-            if (pos + jump > endpos) return false; // Jump out of range
+            if (int64_t{jump} > int64_t{endpos - pos}) return false; // Jump out of range
             if (bits == 0) return false; // Consuming bits past the end of the input
             --bits;
             uint32_t jump_offset = pos - begin + jump;
diff --git a/src/util/hash_type.h b/src/util/hash_type.h
new file mode 100644
index 0000000000..13b831cf19
--- /dev/null
+++ b/src/util/hash_type.h
@@ -0,0 +1,72 @@
+// Copyright (c) 2020-2021 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_UTIL_HASH_TYPE_H
+#define BITCOIN_UTIL_HASH_TYPE_H
+
+template <typename HashType>
+class BaseHash
+{
+protected:
+    HashType m_hash;
+
+public:
+    BaseHash() : m_hash() {}
+    explicit BaseHash(const HashType& in) : m_hash(in) {}
+
+    unsigned char* begin()
+    {
+        return m_hash.begin();
+    }
+
+    const unsigned char* begin() const
+    {
+        return m_hash.begin();
+    }
+
+    unsigned char* end()
+    {
+        return m_hash.end();
+    }
+
+    const unsigned char* end() const
+    {
+        return m_hash.end();
+    }
+
+    operator std::vector<unsigned char>() const
+    {
+        return std::vector<unsigned char>{m_hash.begin(), m_hash.end()};
+    }
+
+    std::string ToString() const
+    {
+        return m_hash.ToString();
+    }
+
+    bool operator==(const BaseHash<HashType>& other) const noexcept
+    {
+        return m_hash == other.m_hash;
+    }
+
+    bool operator!=(const BaseHash<HashType>& other) const noexcept
+    {
+        return !(m_hash == other.m_hash);
+    }
+
+    bool operator<(const BaseHash<HashType>& other) const noexcept
+    {
+        return m_hash < other.m_hash;
+    }
+
+    size_t size() const
+    {
+        return m_hash.size();
+    }
+
+    unsigned char* data() { return m_hash.data(); }
+    const unsigned char* data() const { return m_hash.data(); }
+};
+
+#endif // BITCOIN_UTIL_HASH_TYPE_H
diff --git a/src/util/serfloat.cpp b/src/util/serfloat.cpp
new file mode 100644
index 0000000000..8edca924cd
--- /dev/null
+++ b/src/util/serfloat.cpp
@@ -0,0 +1,64 @@
+// Copyright (c) 2021 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 <util/serfloat.h>
+
+#include <cmath>
+#include <limits>
+
+double DecodeDouble(uint64_t v) noexcept {
+    static constexpr double NANVAL = std::numeric_limits<double>::quiet_NaN();
+    static constexpr double INFVAL = std::numeric_limits<double>::infinity();
+    double sign = 1.0;
+    if (v & 0x8000000000000000) {
+        sign = -1.0;
+        v ^= 0x8000000000000000;
+    }
+    // Zero
+    if (v == 0) return copysign(0.0, sign);
+    // Infinity
+    if (v == 0x7ff0000000000000) return copysign(INFVAL, sign);
+    // Other numbers
+    int exp = (v & 0x7FF0000000000000) >> 52;
+    uint64_t man = v & 0xFFFFFFFFFFFFF;
+    if (exp == 2047) {
+        // NaN
+        return NANVAL;
+    } else if (exp == 0) {
+        // Subnormal
+        return copysign(ldexp((double)man, -1074), sign);
+    } else {
+        // Normal
+        return copysign(ldexp((double)(man + 0x10000000000000), -1075 + exp), sign);
+    }
+}
+
+uint64_t EncodeDouble(double f) noexcept {
+    int cls = std::fpclassify(f);
+    uint64_t sign = 0;
+    if (copysign(1.0, f) == -1.0) {
+        f = -f;
+        sign = 0x8000000000000000;
+    }
+    // Zero
+    if (cls == FP_ZERO) return sign;
+    // Infinity
+    if (cls == FP_INFINITE) return sign | 0x7ff0000000000000;
+    // NaN
+    if (cls == FP_NAN) return 0x7ff8000000000000;
+    // Other numbers
+    int exp;
+    uint64_t man = std::round(std::frexp(f, &exp) * 9007199254740992.0);
+    if (exp < -1021) {
+        // Too small to represent, encode 0
+        if (exp < -1084) return sign;
+        // Subnormal numbers
+        return sign | (man >> (-1021 - exp));
+    } else {
+        // Too big to represent, encode infinity
+        if (exp > 1024) return sign | 0x7ff0000000000000;
+        // Normal numbers
+        return sign | (((uint64_t)(1022 + exp)) << 52) | (man & 0xFFFFFFFFFFFFF);
+    }
+}
diff --git a/src/util/serfloat.h b/src/util/serfloat.h
new file mode 100644
index 0000000000..4d912b0176
--- /dev/null
+++ b/src/util/serfloat.h
@@ -0,0 +1,16 @@
+// Copyright (c) 2021 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_UTIL_SERFLOAT_H
+#define BITCOIN_UTIL_SERFLOAT_H
+
+#include <stdint.h>
+
+/* Encode a double using the IEEE 754 binary64 format. All NaNs are encoded as x86/ARM's
+ * positive quiet NaN with payload 0. */
+uint64_t EncodeDouble(double f) noexcept;
+/* Reverse operation of DecodeDouble. DecodeDouble(EncodeDouble(f))==f unless isnan(f). */
+double DecodeDouble(uint64_t v) noexcept;
+
+#endif // BITCOIN_UTIL_SERFLOAT_H
diff --git a/src/util/sock.cpp b/src/util/sock.cpp
index 0bc9795db3..b6c2a47434 100644
--- a/src/util/sock.cpp
+++ b/src/util/sock.cpp
@@ -179,7 +179,7 @@ void Sock::SendComplete(const std::string& data,
         // Wait for a short while (or the socket to become ready for sending) before retrying
         // if nothing was sent.
         const auto wait_time = std::min(deadline - now, std::chrono::milliseconds{MAX_WAIT_FOR_IO});
-        Wait(wait_time, SEND);
+        (void)Wait(wait_time, SEND);
     }
 }
 
@@ -262,7 +262,7 @@ std::string Sock::RecvUntilTerminator(uint8_t terminator,
 
         // Wait for a short while (or the socket to become ready for reading) before retrying.
         const auto wait_time = std::min(deadline - now, std::chrono::milliseconds{MAX_WAIT_FOR_IO});
-        Wait(wait_time, RECV);
+        (void)Wait(wait_time, RECV);
     }
 }
 
diff --git a/src/util/sock.h b/src/util/sock.h
index c4ad0cbc43..59cc8c0b1d 100644
--- a/src/util/sock.h
+++ b/src/util/sock.h
@@ -64,7 +64,7 @@ public:
      * Get the value of the contained socket.
      * @return socket or INVALID_SOCKET if empty
      */
-    virtual SOCKET Get() const;
+    [[nodiscard]] virtual SOCKET Get() const;
 
     /**
      * Get the value of the contained socket and drop ownership. It will not be closed by the
@@ -82,26 +82,29 @@ public:
      * send(2) wrapper. Equivalent to `send(this->Get(), data, len, flags);`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
-    virtual ssize_t Send(const void* data, size_t len, int flags) const;
+    [[nodiscard]] virtual ssize_t Send(const void* data, size_t len, int flags) const;
 
     /**
      * recv(2) wrapper. Equivalent to `recv(this->Get(), buf, len, flags);`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
-    virtual ssize_t Recv(void* buf, size_t len, int flags) const;
+    [[nodiscard]] virtual ssize_t Recv(void* buf, size_t len, int flags) const;
 
     /**
      * connect(2) wrapper. Equivalent to `connect(this->Get(), addr, addrlen)`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
-    virtual int Connect(const sockaddr* addr, socklen_t addr_len) const;
+    [[nodiscard]] virtual int Connect(const sockaddr* addr, socklen_t addr_len) const;
 
     /**
      * getsockopt(2) wrapper. Equivalent to
      * `getsockopt(this->Get(), level, opt_name, opt_val, opt_len)`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
-    virtual int GetSockOpt(int level, int opt_name, void* opt_val, socklen_t* opt_len) const;
+    [[nodiscard]] virtual int GetSockOpt(int level,
+                                         int opt_name,
+                                         void* opt_val,
+                                         socklen_t* opt_len) const;
 
     using Event = uint8_t;
 
@@ -124,9 +127,9 @@ public:
      * value of `true` and `occurred` being set to 0.
      * @return true on success and false otherwise
      */
-    virtual bool Wait(std::chrono::milliseconds timeout,
-                      Event requested,
-                      Event* occurred = nullptr) const;
+    [[nodiscard]] virtual bool Wait(std::chrono::milliseconds timeout,
+                                    Event requested,
+                                    Event* occurred = nullptr) const;
 
     /* Higher level, convenience, methods. These may throw. */
 
@@ -154,17 +157,17 @@ public:
      * @throws std::runtime_error if the operation cannot be completed. In this case some bytes may
      * have been consumed from the socket.
      */
-    virtual std::string RecvUntilTerminator(uint8_t terminator,
-                                            std::chrono::milliseconds timeout,
-                                            CThreadInterrupt& interrupt,
-                                            size_t max_data) const;
+    [[nodiscard]] virtual std::string RecvUntilTerminator(uint8_t terminator,
+                                                          std::chrono::milliseconds timeout,
+                                                          CThreadInterrupt& interrupt,
+                                                          size_t max_data) const;
 
     /**
      * Check if still connected.
-     * @param[out] err The error string, if the socket has been disconnected.
+     * @param[out] errmsg The error string, if the socket has been disconnected.
      * @return true if connected
      */
-    virtual bool IsConnected(std::string& errmsg) const;
+    [[nodiscard]] virtual bool IsConnected(std::string& errmsg) const;
 
 protected:
     /**
diff --git a/src/util/spanparsing.cpp b/src/util/spanparsing.cpp
index 0f68254f2c..e2e2782bec 100644
--- a/src/util/spanparsing.cpp
+++ b/src/util/spanparsing.cpp
@@ -34,11 +34,11 @@ Span<const char> Expr(Span<const char>& sp)
     int level = 0;
     auto it = sp.begin();
     while (it != sp.end()) {
-        if (*it == '(') {
+        if (*it == '(' || *it == '{') {
             ++level;
-        } else if (level && *it == ')') {
+        } else if (level && (*it == ')' || *it == '}')) {
             --level;
-        } else if (level == 0 && (*it == ')' || *it == ',')) {
+        } else if (level == 0 && (*it == ')' || *it == '}' || *it == ',')) {
             break;
         }
         ++it;
diff --git a/src/util/strencodings.cpp b/src/util/strencodings.cpp
index 4734de3e0b..f514613f0d 100644
--- a/src/util/strencodings.cpp
+++ b/src/util/strencodings.cpp
@@ -593,13 +593,14 @@ std::string Capitalize(std::string str)
 
 std::string HexStr(const Span<const uint8_t> s)
 {
-    std::string rv;
+    std::string rv(s.size() * 2, '\0');
     static constexpr char hexmap[16] = { '0', '1', '2', '3', '4', '5', '6', '7',
                                          '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
-    rv.reserve(s.size() * 2);
-    for (uint8_t v: s) {
-        rv.push_back(hexmap[v >> 4]);
-        rv.push_back(hexmap[v & 15]);
+    auto it = rv.begin();
+    for (uint8_t v : s) {
+        *it++ = hexmap[v >> 4];
+        *it++ = hexmap[v & 15];
     }
+    assert(it == rv.end());
     return rv;
 }
diff --git a/src/util/system.cpp b/src/util/system.cpp
index 0b83a76504..13ccf7463e 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -235,6 +235,19 @@ static bool CheckValid(const std::string& key, const util::SettingsValue& val, u
     return true;
 }
 
+namespace {
+fs::path StripRedundantLastElementsOfPath(const fs::path& path)
+{
+    auto result = path;
+    while (result.filename().string() == ".") {
+        result = result.parent_path();
+    }
+
+    assert(fs::equivalent(result, path));
+    return result;
+}
+} // namespace
+
 // Define default constructor and destructor that are not inline, so code instantiating this class doesn't need to
 // #include class definitions for all members.
 // For example, m_settings has an internal dependency on univalue.
@@ -352,15 +365,16 @@ bool ArgsManager::ParseParameters(int argc, const char* const argv[], std::strin
         m_settings.command_line_options[key].push_back(value);
     }
 
-    // we do not allow -includeconf from command line
-    bool success = true;
+    // we do not allow -includeconf from command line, only -noincludeconf
     if (auto* includes = util::FindKey(m_settings.command_line_options, "includeconf")) {
-        for (const auto& include : util::SettingsSpan(*includes)) {
-            error += "-includeconf cannot be used from commandline; -includeconf=" + include.get_str() + "\n";
-            success = false;
+        const util::SettingsSpan values{*includes};
+        // Range may be empty if -noincludeconf was passed
+        if (!values.empty()) {
+            error = "-includeconf cannot be used from commandline; -includeconf=" + values.begin()->write();
+            return false; // pick first value as example
         }
     }
-    return success;
+    return true;
 }
 
 std::optional<unsigned int> ArgsManager::GetArgFlags(const std::string& name) const
@@ -375,6 +389,72 @@ std::optional<unsigned int> ArgsManager::GetArgFlags(const std::string& name) co
     return std::nullopt;
 }
 
+const fs::path& ArgsManager::GetBlocksDirPath() const
+{
+    LOCK(cs_args);
+    fs::path& path = m_cached_blocks_path;
+
+    // Cache the path to avoid calling fs::create_directories on every call of
+    // this function
+    if (!path.empty()) return path;
+
+    if (IsArgSet("-blocksdir")) {
+        path = fs::system_complete(GetArg("-blocksdir", ""));
+        if (!fs::is_directory(path)) {
+            path = "";
+            return path;
+        }
+    } else {
+        path = GetDataDirBase();
+    }
+
+    path /= BaseParams().DataDir();
+    path /= "blocks";
+    fs::create_directories(path);
+    path = StripRedundantLastElementsOfPath(path);
+    return path;
+}
+
+const fs::path& ArgsManager::GetDataDir(bool net_specific) const
+{
+    LOCK(cs_args);
+    fs::path& path = net_specific ? m_cached_network_datadir_path : m_cached_datadir_path;
+
+    // Cache the path to avoid calling fs::create_directories on every call of
+    // this function
+    if (!path.empty()) return path;
+
+    std::string datadir = GetArg("-datadir", "");
+    if (!datadir.empty()) {
+        path = fs::system_complete(datadir);
+        if (!fs::is_directory(path)) {
+            path = "";
+            return path;
+        }
+    } else {
+        path = GetDefaultDataDir();
+    }
+    if (net_specific)
+        path /= BaseParams().DataDir();
+
+    if (fs::create_directories(path)) {
+        // This is the first run, create wallets subdirectory too
+        fs::create_directories(path / "wallets");
+    }
+
+    path = StripRedundantLastElementsOfPath(path);
+    return path;
+}
+
+void ArgsManager::ClearPathCache()
+{
+    LOCK(cs_args);
+
+    m_cached_datadir_path = fs::path();
+    m_cached_network_datadir_path = fs::path();
+    m_cached_blocks_path = fs::path();
+}
+
 std::optional<const ArgsManager::Command> ArgsManager::GetCommand() const
 {
     Command ret;
@@ -434,7 +514,7 @@ bool ArgsManager::GetSettingsPath(fs::path* filepath, bool temp) const
     }
     if (filepath) {
         std::string settings = GetArg("-settings", BITCOIN_SETTINGS_FILENAME);
-        *filepath = fsbridge::AbsPathJoin(GetDataDir(/* net_specific= */ true), temp ? settings + ".tmp" : settings);
+        *filepath = fsbridge::AbsPathJoin(GetDataDirNet(), temp ? settings + ".tmp" : settings);
     }
     return true;
 }
@@ -723,96 +803,12 @@ fs::path GetDefaultDataDir()
 #endif
 }
 
-namespace {
-fs::path StripRedundantLastElementsOfPath(const fs::path& path)
-{
-    auto result = path;
-    while (result.filename().string() == ".") {
-        result = result.parent_path();
-    }
-
-    assert(fs::equivalent(result, path));
-    return result;
-}
-} // namespace
-
-static fs::path g_blocks_path_cache_net_specific;
-static fs::path pathCached;
-static fs::path pathCachedNetSpecific;
-static RecursiveMutex csPathCached;
-
-const fs::path &GetBlocksDir()
-{
-    LOCK(csPathCached);
-    fs::path &path = g_blocks_path_cache_net_specific;
-
-    // Cache the path to avoid calling fs::create_directories on every call of
-    // this function
-    if (!path.empty()) return path;
-
-    if (gArgs.IsArgSet("-blocksdir")) {
-        path = fs::system_complete(gArgs.GetArg("-blocksdir", ""));
-        if (!fs::is_directory(path)) {
-            path = "";
-            return path;
-        }
-    } else {
-        path = GetDataDir(false);
-    }
-
-    path /= BaseParams().DataDir();
-    path /= "blocks";
-    fs::create_directories(path);
-    path = StripRedundantLastElementsOfPath(path);
-    return path;
-}
-
-const fs::path &GetDataDir(bool fNetSpecific)
-{
-    LOCK(csPathCached);
-    fs::path &path = fNetSpecific ? pathCachedNetSpecific : pathCached;
-
-    // Cache the path to avoid calling fs::create_directories on every call of
-    // this function
-    if (!path.empty()) return path;
-
-    std::string datadir = gArgs.GetArg("-datadir", "");
-    if (!datadir.empty()) {
-        path = fs::system_complete(datadir);
-        if (!fs::is_directory(path)) {
-            path = "";
-            return path;
-        }
-    } else {
-        path = GetDefaultDataDir();
-    }
-    if (fNetSpecific)
-        path /= BaseParams().DataDir();
-
-    if (fs::create_directories(path)) {
-        // This is the first run, create wallets subdirectory too
-        fs::create_directories(path / "wallets");
-    }
-
-    path = StripRedundantLastElementsOfPath(path);
-    return path;
-}
-
 bool CheckDataDirOption()
 {
     std::string datadir = gArgs.GetArg("-datadir", "");
     return datadir.empty() || fs::is_directory(fs::system_complete(datadir));
 }
 
-void ClearDatadirCache()
-{
-    LOCK(csPathCached);
-
-    pathCached = fs::path();
-    pathCachedNetSpecific = fs::path();
-    g_blocks_path_cache_net_specific = fs::path();
-}
-
 fs::path GetConfigFile(const std::string& confPath)
 {
     return AbsPathForConfigVal(fs::path(confPath), false);
@@ -971,7 +967,7 @@ bool ArgsManager::ReadConfigFiles(std::string& error, bool ignore_invalid_keys)
     }
 
     // If datadir is changed in .conf file:
-    ClearDatadirCache();
+    gArgs.ClearPathCache();
     if (!CheckDataDirOption()) {
         error = strprintf("specified data directory \"%s\" does not exist.", GetArg("-datadir", ""));
         return false;
@@ -1361,7 +1357,7 @@ fs::path AbsPathForConfigVal(const fs::path& path, bool net_specific)
     if (path.is_absolute()) {
         return path;
     }
-    return fsbridge::AbsPathJoin(GetDataDir(net_specific), path);
+    return fsbridge::AbsPathJoin(net_specific ? gArgs.GetDataDirNet() : gArgs.GetDataDirBase(), path);
 }
 
 void ScheduleBatchPriority()
diff --git a/src/util/system.h b/src/util/system.h
index 29657e56e2..c4317c62d0 100644
--- a/src/util/system.h
+++ b/src/util/system.h
@@ -22,7 +22,6 @@
 #include <sync.h>
 #include <tinyformat.h>
 #include <util/settings.h>
-#include <util/threadnames.h>
 #include <util/time.h>
 
 #include <any>
@@ -91,13 +90,8 @@ void ReleaseDirectoryLocks();
 
 bool TryCreateDirectories(const fs::path& p);
 fs::path GetDefaultDataDir();
-// The blocks directory is always net specific.
-const fs::path &GetBlocksDir();
-const fs::path &GetDataDir(bool fNetSpecific = true);
 // Return true if -datadir option points to a valid directory or is not specified.
 bool CheckDataDirOption();
-/** Tests only */
-void ClearDatadirCache();
 fs::path GetConfigFile(const std::string& confPath);
 #ifdef WIN32
 fs::path GetSpecialFolderPath(int nFolder, bool fCreate = true);
@@ -124,7 +118,7 @@ UniValue RunCommandParseJSON(const std::string& str_command, const std::string&
  * the datadir if they are not absolute.
  *
  * @param path The path to be conditionally prefixed with datadir.
- * @param net_specific Forwarded to GetDataDir().
+ * @param net_specific Use network specific datadir variant
  * @return The normalized path.
  */
 fs::path AbsPathForConfigVal(const fs::path& path, bool net_specific = true);
@@ -200,6 +194,9 @@ protected:
     std::map<OptionsCategory, std::map<std::string, Arg>> m_available_args GUARDED_BY(cs_args);
     bool m_accept_any_command GUARDED_BY(cs_args){true};
     std::list<SectionInfo> m_config_sections GUARDED_BY(cs_args);
+    mutable fs::path m_cached_blocks_path GUARDED_BY(cs_args);
+    mutable fs::path m_cached_datadir_path GUARDED_BY(cs_args);
+    mutable fs::path m_cached_network_datadir_path GUARDED_BY(cs_args);
 
     [[nodiscard]] bool ReadConfigStream(std::istream& stream, const std::string& filepath, std::string& error, bool ignore_invalid_keys = false);
 
@@ -264,6 +261,34 @@ public:
     std::optional<const Command> GetCommand() const;
 
     /**
+     * Get blocks directory path
+     *
+     * @return Blocks path which is network specific
+     */
+    const fs::path& GetBlocksDirPath() const;
+
+    /**
+     * Get data directory path
+     *
+     * @return Absolute path on success, otherwise an empty path when a non-directory path would be returned
+     * @post Returned directory path is created unless it is empty
+     */
+    const fs::path& GetDataDirBase() const { return GetDataDir(false); }
+
+    /**
+     * Get data directory path with appended network identifier
+     *
+     * @return Absolute path on success, otherwise an empty path when a non-directory path would be returned
+     * @post Returned directory path is created unless it is empty
+     */
+    const fs::path& GetDataDirNet() const { return GetDataDir(true); }
+
+    /**
+     * Clear cached directory paths
+     */
+    void ClearPathCache();
+
+    /**
      * Return a vector of strings of the given argument
      *
      * @param strArg Argument to get (e.g. "-foo")
@@ -418,6 +443,15 @@ public:
     void LogArgs() const;
 
 private:
+    /**
+     * Get data directory path
+     *
+     * @param net_specific Append network identifier to the returned path
+     * @return Absolute path on success, otherwise an empty path when a non-directory path would be returned
+     * @post Returned directory path is created unless it is empty
+     */
+    const fs::path& GetDataDir(bool net_specific) const;
+
     // Helper function for LogArgs().
     void logArgsPrefix(
         const std::string& prefix,
@@ -458,28 +492,6 @@ std::string HelpMessageOpt(const std::string& option, const std::string& message
  */
 int GetNumCores();
 
-/**
- * .. and a wrapper that just calls func once
- */
-template <typename Callable> void TraceThread(const char* name,  Callable func)
-{
-    util::ThreadRename(name);
-    try
-    {
-        LogPrintf("%s thread start\n", name);
-        func();
-        LogPrintf("%s thread exit\n", name);
-    }
-    catch (const std::exception& e) {
-        PrintExceptionContinue(&e, name);
-        throw;
-    }
-    catch (...) {
-        PrintExceptionContinue(nullptr, name);
-        throw;
-    }
-}
-
 std::string CopyrightHolders(const std::string& strPrefix);
 
 /**
diff --git a/src/util/thread.cpp b/src/util/thread.cpp
new file mode 100644
index 0000000000..14be668685
--- /dev/null
+++ b/src/util/thread.cpp
@@ -0,0 +1,27 @@
+// Copyright (c) 2021 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 <util/thread.h>
+
+#include <logging.h>
+#include <util/system.h>
+#include <util/threadnames.h>
+
+#include <exception>
+
+void util::TraceThread(const char* thread_name, std::function<void()> thread_func)
+{
+    util::ThreadRename(thread_name);
+    try {
+        LogPrintf("%s thread start\n", thread_name);
+        thread_func();
+        LogPrintf("%s thread exit\n", thread_name);
+    } catch (const std::exception& e) {
+        PrintExceptionContinue(&e, thread_name);
+        throw;
+    } catch (...) {
+        PrintExceptionContinue(nullptr, thread_name);
+        throw;
+    }
+}
diff --git a/src/util/thread.h b/src/util/thread.h
new file mode 100644
index 0000000000..ca2eccc0c3
--- /dev/null
+++ b/src/util/thread.h
@@ -0,0 +1,18 @@
+// Copyright (c) 2021 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_UTIL_THREAD_H
+#define BITCOIN_UTIL_THREAD_H
+
+#include <functional>
+
+namespace util {
+/**
+ * A wrapper for do-something-once thread functions.
+ */
+void TraceThread(const char* thread_name, std::function<void()> thread_func);
+
+} // namespace util
+
+#endif // BITCOIN_UTIL_THREAD_H
diff --git a/src/util/time.cpp b/src/util/time.cpp
index e6f0986a39..eda710b12c 100644
--- a/src/util/time.cpp
+++ b/src/util/time.cpp
@@ -124,7 +124,7 @@ int64_t GetTimeMicros()
     return int64_t{GetSystemTime<std::chrono::microseconds>().count()};
 }
 
-int64_t GetSystemTimeInSeconds()
+int64_t GetTimeSeconds()
 {
     return int64_t{GetSystemTime<std::chrono::seconds>().count()};
 }
diff --git a/src/util/time.h b/src/util/time.h
index 7ebcaaa339..4aee01967d 100644
--- a/src/util/time.h
+++ b/src/util/time.h
@@ -39,7 +39,7 @@ inline double CountSecondsDouble(SecondsDouble t) { return t.count(); }
 
 /**
  * DEPRECATED
- * Use either GetSystemTimeInSeconds (not mockable) or GetTime<T> (mockable)
+ * Use either GetTimeSeconds (not mockable) or GetTime<T> (mockable)
  */
 int64_t GetTime();
 
@@ -48,7 +48,7 @@ int64_t GetTimeMillis();
 /** Returns the system time (not mockable) */
 int64_t GetTimeMicros();
 /** Returns the system time (not mockable) */
-int64_t GetSystemTimeInSeconds(); // Like GetTime(), but not mockable
+int64_t GetTimeSeconds(); // Like GetTime(), but not mockable
 
 /**
  * DEPRECATED