net: rename Sock::Reset() to Sock::Close() and make it private

Outside of `Sock`, `Sock::Reset()` was used in just one place (in
`i2p.cpp`) which can use the assignment operator instead.

This simplifies the public `Sock` API by having one method less.

src/i2p.cpp

@@ -410,7 +410,7 @@ void Session::Disconnect()
             Log("Destroying session %s", m_session_id);
         }
     }
-    m_control_sock->Reset();
+    m_control_sock = std::make_unique<Sock>(INVALID_SOCKET);
     m_session_id.clear();
 }
 } // namespace sam

src/test/fuzz/util.cpp

@@ -24,10 +24,10 @@ FuzzedSock::FuzzedSock(FuzzedDataProvider& fuzzed_data_provider)
 FuzzedSock::~FuzzedSock()
 {
     // Sock::~Sock() will be called after FuzzedSock::~FuzzedSock() and it will call
-    // Sock::Reset() (not FuzzedSock::Reset()!) which will call close(m_socket).
+    // close(m_socket) if m_socket is not INVALID_SOCKET.
     // Avoid closing an arbitrary file descriptor (m_socket is just a random very high number which
     // theoretically may concide with a real opened file descriptor).
-    Reset();
+    m_socket = INVALID_SOCKET;
 }
 
 FuzzedSock& FuzzedSock::operator=(Sock&& other)
@@ -36,11 +36,6 @@ FuzzedSock& FuzzedSock::operator=(Sock&& other)
     return *this;
 }
 
-void FuzzedSock::Reset()
-{
-    m_socket = INVALID_SOCKET;
-}
-
 ssize_t FuzzedSock::Send(const void* data, size_t len, int flags) const
 {
     constexpr std::array send_errnos{

src/test/fuzz/util.h

@@ -55,8 +55,6 @@ public:
 
     FuzzedSock& operator=(Sock&& other) override;
 
-    void Reset() override;
-
     ssize_t Send(const void* data, size_t len, int flags) const override;
 
     ssize_t Recv(void* buf, size_t len, int flags) const override;

src/test/sock_tests.cpp

@@ -69,14 +69,6 @@ BOOST_AUTO_TEST_CASE(move_assignment)
     BOOST_CHECK(SocketIsClosed(s));
 }
 
-BOOST_AUTO_TEST_CASE(reset)
-{
-    const SOCKET s = CreateSocket();
-    Sock sock(s);
-    sock.Reset();
-    BOOST_CHECK(SocketIsClosed(s));
-}
-
 #ifndef WIN32 // Windows does not have socketpair(2).
 
 static void CreateSocketPair(int s[2])

src/test/util/net.h

@@ -100,7 +100,7 @@ public:
         m_socket = INVALID_SOCKET - 1;
     }
 
-    ~StaticContentsSock() override { Reset(); }
+    ~StaticContentsSock() override { m_socket = INVALID_SOCKET; }
 
     StaticContentsSock& operator=(Sock&& other) override
     {
@@ -108,11 +108,6 @@ public:
         return *this;
     }
 
-    void Reset() override
-    {
-        m_socket = INVALID_SOCKET;
-    }
-
     ssize_t Send(const void*, size_t len, int) const override { return len; }
 
     ssize_t Recv(void* buf, size_t len, int flags) const override

src/util/sock.cpp

@@ -39,11 +39,11 @@ Sock::Sock(Sock&& other)
     other.m_socket = INVALID_SOCKET;
 }
 
-Sock::~Sock() { Reset(); }
+Sock::~Sock() { Close(); }
 
 Sock& Sock::operator=(Sock&& other)
 {
-    Reset();
+    Close();
     m_socket = other.m_socket;
     other.m_socket = INVALID_SOCKET;
     return *this;
@@ -51,21 +51,6 @@ Sock& Sock::operator=(Sock&& other)
 
 SOCKET Sock::Get() const { return m_socket; }
 
-void Sock::Reset() {
-    if (m_socket == INVALID_SOCKET) {
-        return;
-    }
-#ifdef WIN32
-    int ret = closesocket(m_socket);
-#else
-    int ret = close(m_socket);
-#endif
-    if (ret) {
-        LogPrintf("Error closing socket %d: %s\n", m_socket, NetworkErrorString(WSAGetLastError()));
-    }
-    m_socket = INVALID_SOCKET;
-}
-
 ssize_t Sock::Send(const void* data, size_t len, int flags) const
 {
     return send(m_socket, static_cast<const char*>(data), len, flags);
@@ -372,6 +357,22 @@ bool Sock::IsConnected(std::string& errmsg) const
     }
 }
 
+void Sock::Close()
+{
+    if (m_socket == INVALID_SOCKET) {
+        return;
+    }
+#ifdef WIN32
+    int ret = closesocket(m_socket);
+#else
+    int ret = close(m_socket);
+#endif
+    if (ret) {
+        LogPrintf("Error closing socket %d: %s\n", m_socket, NetworkErrorString(WSAGetLastError()));
+    }
+    m_socket = INVALID_SOCKET;
+}
+
 #ifdef WIN32
 std::string NetworkErrorString(int err)
 {

src/util/sock.h

@@ -68,11 +68,6 @@ public:
      */
     [[nodiscard]] virtual SOCKET Get() const;
 
-    /**
-     * Close if non-empty.
-     */
-    virtual void Reset();
-
     /**
      * 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.
@@ -245,6 +240,12 @@ protected:
      * Contained socket. `INVALID_SOCKET` designates the object is empty.
      */
     SOCKET m_socket;
+
+private:
+    /**
+     * Close `m_socket` if it is not `INVALID_SOCKET`.
+     */
+    void Close();
 };
 
 /** Return readable error string for a network error code */