Merge bitcoin/bitcoin#26312: Remove Sock::Get() and Sock::Sock()

7df450836969b81e98322c9a09c08b35d1095a25 test: improve sock_tests/move_assignment (Vasil Dimov)
5086a99b84367a45706af7197da1016dd966e6d9 net: remove Sock default constructor, it's not necessary (Vasil Dimov)
7829272f7826511241defd34954e6040ea963f07 net: remove now unnecessary Sock::Get() (Vasil Dimov)
944b21b70ae490a5a746bcc1810a5074d74e9d34 net: don't check if the socket is valid in ConnectSocketDirectly() (Vasil Dimov)
aeac68d036e3cff57ce155f1a904d77f98b357d4 net: don't check if the socket is valid in GetBindAddress() (Vasil Dimov)
5ac1a51ee5a57da59f1ff1986b7d9054484d3c80 i2p: avoid using Sock::Get() for checking for a valid socket (Vasil Dimov)

Pull request description:

  _This is a piece of #21878, chopped off to ease review._

  Peeking at the underlying socket file descriptor of `Sock` and checkig if it is `INVALID_SOCKET` is bad encapsulation and stands in the way of testing/mocking/fuzzing.

  Instead use an empty `unique_ptr` to denote that there is no valid socket where appropriate or outright remove such checks where they are not necessary.

  The default constructor `Sock::Sock()` is unnecessary now after recent changes, thus remove it.

ACKs for top commit:
  ajtowns:
    ACK 7df450836969b81e98322c9a09c08b35d1095a25
  jonatack:
    ACK 7df450836969b81e98322c9a09c08b35d1095a25

Tree-SHA512: 9742aeeeabe8690530bf74caa6ba296787028c52f4a3342afd193b05dbbb1f6645935c33ba0a5230199a09af01c666bd3c7fb16b48692a0d185356ea59a8ddbf

2 files changed, 21 insertions, 25 deletions

diff --git a/src/util/sock.cpp b/src/util/sock.cpp
index fd64cae404..d16dc56aa3 100644
--- a/src/util/sock.cpp
+++ b/src/util/sock.cpp
@@ -24,8 +24,6 @@ static inline bool IOErrorIsPermanent(int err)
     return err != WSAEAGAIN && err != WSAEINTR && err != WSAEWOULDBLOCK && err != WSAEINPROGRESS;
 }
 
-Sock::Sock() : m_socket(INVALID_SOCKET) {}
-
 Sock::Sock(SOCKET s) : m_socket(s) {}
 
 Sock::Sock(Sock&& other)
@@ -44,8 +42,6 @@ Sock& Sock::operator=(Sock&& other)
     return *this;
 }
 
-SOCKET Sock::Get() const { return m_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);
@@ -411,6 +407,11 @@ void Sock::Close()
     m_socket = INVALID_SOCKET;
 }
 
+bool Sock::operator==(SOCKET s) const
+{
+    return m_socket == s;
+};
+
 std::string NetworkErrorString(int err)
 {
 #if defined(WIN32)
diff --git a/src/util/sock.h b/src/util/sock.h
index 6bac2dfd34..d78e01929b 100644
--- a/src/util/sock.h
+++ b/src/util/sock.h
@@ -21,16 +21,12 @@
 static constexpr auto MAX_WAIT_FOR_IO = 1s;
 
 /**
- * RAII helper class that manages a socket. Mimics `std::unique_ptr`, but instead of a pointer it
- * contains a socket and closes it automatically when it goes out of scope.
+ * RAII helper class that manages a socket and closes it automatically when it goes out of scope.
  */
 class Sock
 {
 public:
-    /**
-     * Default constructor, creates an empty object that does nothing when destroyed.
-     */
-    Sock();
+    Sock() = delete;
 
     /**
      * Take ownership of an existent socket.
@@ -63,43 +59,37 @@ public:
     virtual Sock& operator=(Sock&& other);
 
     /**
-     * Get the value of the contained socket.
-     * @return socket or INVALID_SOCKET if empty
-     */
-    [[nodiscard]] virtual SOCKET Get() const;
-
-    /**
-     * send(2) wrapper. Equivalent to `send(this->Get(), data, len, flags);`. Code that uses this
+     * send(2) wrapper. Equivalent to `send(m_socket, data, len, flags);`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     [[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
+     * recv(2) wrapper. Equivalent to `recv(m_socket, buf, len, flags);`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     [[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
+     * connect(2) wrapper. Equivalent to `connect(m_socket, addr, addrlen)`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     [[nodiscard]] virtual int Connect(const sockaddr* addr, socklen_t addr_len) const;
 
     /**
-     * bind(2) wrapper. Equivalent to `bind(this->Get(), addr, addr_len)`. Code that uses this
+     * bind(2) wrapper. Equivalent to `bind(m_socket, addr, addr_len)`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     [[nodiscard]] virtual int Bind(const sockaddr* addr, socklen_t addr_len) const;
 
     /**
-     * listen(2) wrapper. Equivalent to `listen(this->Get(), backlog)`. Code that uses this
+     * listen(2) wrapper. Equivalent to `listen(m_socket, backlog)`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     [[nodiscard]] virtual int Listen(int backlog) const;
 
     /**
-     * accept(2) wrapper. Equivalent to `std::make_unique<Sock>(accept(this->Get(), addr, addr_len))`.
+     * accept(2) wrapper. Equivalent to `std::make_unique<Sock>(accept(m_socket, addr, addr_len))`.
      * Code that uses this wrapper can be unit tested if this method is overridden by a mock Sock
      * implementation.
      * The returned unique_ptr is empty if `accept()` failed in which case errno will be set.
@@ -108,7 +98,7 @@ public:
 
     /**
      * getsockopt(2) wrapper. Equivalent to
-     * `getsockopt(this->Get(), level, opt_name, opt_val, opt_len)`. Code that uses this
+     * `getsockopt(m_socket, 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.
      */
     [[nodiscard]] virtual int GetSockOpt(int level,
@@ -118,7 +108,7 @@ public:
 
     /**
      * setsockopt(2) wrapper. Equivalent to
-     * `setsockopt(this->Get(), level, opt_name, opt_val, opt_len)`. Code that uses this
+     * `setsockopt(m_socket, 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.
      */
     [[nodiscard]] virtual int SetSockOpt(int level,
@@ -128,7 +118,7 @@ public:
 
     /**
      * getsockname(2) wrapper. Equivalent to
-     * `getsockname(this->Get(), name, name_len)`. Code that uses this
+     * `getsockname(m_socket, name, name_len)`. Code that uses this
      * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     [[nodiscard]] virtual int GetSockName(sockaddr* name, socklen_t* name_len) const;
@@ -266,6 +256,11 @@ public:
      */
     [[nodiscard]] virtual bool IsConnected(std::string& errmsg) const;
 
+    /**
+     * Check if the internal socket is equal to `s`. Use only in tests.
+     */
+    bool operator==(SOCKET s) const;
+
 protected:
     /**
      * Contained socket. `INVALID_SOCKET` designates the object is empty.