net: move CloseSocket() from netbase to util/sock

Move `CloseSocket()` (and `NetworkErrorString()` which it uses) from
`netbase.{h,cpp}` to newly added `src/util/sock.{h,cpp}`.

This is necessary in order to use `CloseSocket()` from a newly
introduced Sock class (which will live in `src/util/sock.{h,cpp}`).
`sock.{h,cpp}` cannot depend on netbase because netbase will depend
on it.

6 files changed, 86 insertions, 55 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 2871df124c..2e35ecdfbd 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -238,6 +238,7 @@ BITCOIN_CORE_H = \
   util/rbf.h \
   util/ref.h \
   util/settings.h \
+  util/sock.h \
   util/spanparsing.h \
   util/string.h \
   util/system.h \
@@ -552,6 +553,7 @@ libbitcoin_util_a_SOURCES = \
   util/error.cpp \
   util/fees.cpp \
   util/hasher.cpp \
+  util/sock.cpp \
   util/system.cpp \
   util/message.cpp \
   util/moneystr.cpp \
diff --git a/src/net.cpp b/src/net.cpp
index 4f74bbede4..38aaeff121 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -20,6 +20,7 @@
 #include <protocol.h>
 #include <random.h>
 #include <scheduler.h>
+#include <util/sock.h>
 #include <util/strencodings.h>
 #include <util/translation.h>
 
diff --git a/src/netbase.cpp b/src/netbase.cpp
index 93c395b9ec..3a3407f901 100644
--- a/src/netbase.cpp
+++ b/src/netbase.cpp
@@ -7,6 +7,7 @@
 
 #include <sync.h>
 #include <tinyformat.h>
+#include <util/sock.h>
 #include <util/strencodings.h>
 #include <util/string.h>
 #include <util/system.h>
@@ -862,57 +863,6 @@ bool LookupSubNet(const std::string& strSubnet, CSubNet& ret)
     return false;
 }
 
-#ifdef WIN32
-std::string NetworkErrorString(int err)
-{
-    wchar_t buf[256];
-    buf[0] = 0;
-    if(FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_MAX_WIDTH_MASK,
-            nullptr, err, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-            buf, ARRAYSIZE(buf), nullptr))
-    {
-        return strprintf("%s (%d)", std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>,wchar_t>().to_bytes(buf), err);
-    }
-    else
-    {
-        return strprintf("Unknown error (%d)", err);
-    }
-}
-#else
-std::string NetworkErrorString(int err)
-{
-    char buf[256];
-    buf[0] = 0;
-    /* Too bad there are two incompatible implementations of the
-     * thread-safe strerror. */
-    const char *s;
-#ifdef STRERROR_R_CHAR_P /* GNU variant can return a pointer outside the passed buffer */
-    s = strerror_r(err, buf, sizeof(buf));
-#else /* POSIX variant always returns message in buffer */
-    s = buf;
-    if (strerror_r(err, buf, sizeof(buf)))
-        buf[0] = 0;
-#endif
-    return strprintf("%s (%d)", s, err);
-}
-#endif
-
-bool CloseSocket(SOCKET& hSocket)
-{
-    if (hSocket == INVALID_SOCKET)
-        return false;
-#ifdef WIN32
-    int ret = closesocket(hSocket);
-#else
-    int ret = close(hSocket);
-#endif
-    if (ret) {
-        LogPrintf("Socket close failed: %d. Error: %s\n", hSocket, NetworkErrorString(WSAGetLastError()));
-    }
-    hSocket = INVALID_SOCKET;
-    return ret != SOCKET_ERROR;
-}
-
 bool SetSocketNonBlocking(const SOCKET& hSocket, bool fNonBlocking)
 {
     if (fNonBlocking) {
diff --git a/src/netbase.h b/src/netbase.h
index 3dc656d0db..38d33e475b 100644
--- a/src/netbase.h
+++ b/src/netbase.h
@@ -54,10 +54,6 @@ bool LookupSubNet(const std::string& strSubnet, CSubNet& subnet);
 SOCKET CreateSocket(const CService &addrConnect);
 bool ConnectSocketDirectly(const CService &addrConnect, const SOCKET& hSocketRet, int nTimeout, bool manual_connection);
 bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int port, const SOCKET& hSocketRet, int nTimeout, bool& outProxyConnectionFailed);
-/** Return readable error string for a network error code */
-std::string NetworkErrorString(int err);
-/** Close socket and set hSocket to INVALID_SOCKET */
-bool CloseSocket(SOCKET& hSocket);
 /** Disable or enable blocking-mode for a socket */
 bool SetSocketNonBlocking(const SOCKET& hSocket, bool fNonBlocking);
 /** Set the TCP_NODELAY flag on a socket */
diff --git a/src/util/sock.cpp b/src/util/sock.cpp
new file mode 100644
index 0000000000..35eca4afb1
--- /dev/null
+++ b/src/util/sock.cpp
@@ -0,0 +1,64 @@
+// 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.
+
+#include <compat.h>
+#include <logging.h>
+#include <tinyformat.h>
+#include <util/sock.h>
+
+#include <codecvt>
+#include <cwchar>
+#include <locale>
+#include <string>
+
+#ifdef WIN32
+std::string NetworkErrorString(int err)
+{
+    wchar_t buf[256];
+    buf[0] = 0;
+    if(FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_MAX_WIDTH_MASK,
+            nullptr, err, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+            buf, ARRAYSIZE(buf), nullptr))
+    {
+        return strprintf("%s (%d)", std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>,wchar_t>().to_bytes(buf), err);
+    }
+    else
+    {
+        return strprintf("Unknown error (%d)", err);
+    }
+}
+#else
+std::string NetworkErrorString(int err)
+{
+    char buf[256];
+    buf[0] = 0;
+    /* Too bad there are two incompatible implementations of the
+     * thread-safe strerror. */
+    const char *s;
+#ifdef STRERROR_R_CHAR_P /* GNU variant can return a pointer outside the passed buffer */
+    s = strerror_r(err, buf, sizeof(buf));
+#else /* POSIX variant always returns message in buffer */
+    s = buf;
+    if (strerror_r(err, buf, sizeof(buf)))
+        buf[0] = 0;
+#endif
+    return strprintf("%s (%d)", s, err);
+}
+#endif
+
+bool CloseSocket(SOCKET& hSocket)
+{
+    if (hSocket == INVALID_SOCKET)
+        return false;
+#ifdef WIN32
+    int ret = closesocket(hSocket);
+#else
+    int ret = close(hSocket);
+#endif
+    if (ret) {
+        LogPrintf("Socket close failed: %d. Error: %s\n", hSocket, NetworkErrorString(WSAGetLastError()));
+    }
+    hSocket = INVALID_SOCKET;
+    return ret != SOCKET_ERROR;
+}
diff --git a/src/util/sock.h b/src/util/sock.h
new file mode 100644
index 0000000000..0d48235043
--- /dev/null
+++ b/src/util/sock.h
@@ -0,0 +1,18 @@
+// 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_SOCK_H
+#define BITCOIN_UTIL_SOCK_H
+
+#include <compat.h>
+
+#include <string>
+
+/** Return readable error string for a network error code */
+std::string NetworkErrorString(int err);
+
+/** Close socket and set hSocket to INVALID_SOCKET */
+bool CloseSocket(SOCKET& hSocket);
+
+#endif // BITCOIN_UTIL_SOCK_H