[2] Inet: Use constructors for Inet EndPoints

#### Problem

`Inet::TCPEndPoint` and `Inet::UDPEndPoint` historically could not use
constructors because of `System::ObjectPool` limitations.

Incidentally renamed `mAppState` for consistency (it had been in
`System::Object` prior to project-chip#11428).

This is a step toward project-chip#7715 _Virtualize System and Inet interfaces_,
split off to reduce the complexity of an upcoming PR.

#### Change overview

Convert from `Init()` to constructors. Transitionally, the constructors
still call a per-implementation function `InitImpl()`.

#### Testing

CI; no changes to functionality.

Author: kpschoedel

src/inet/EndPointBasis.h

@@ -38,36 +38,20 @@ class InetLayer;
 class DLL_EXPORT EndPointBase
 {
 public:
+    EndPointBase(InetLayer & aInetLayer, void * aAppState = nullptr) : AppState(aAppState), mInetLayer(&aInetLayer) {}
+    virtual ~EndPointBase() = default;
+
     /**
      *  Returns a reference to the Inet layer object that owns this basis object.
      */
     InetLayer & Layer() const { return *mInetLayer; }
 
-    /**
-     *  Returns \c true if the basis object was obtained by the specified Inet layer instance.
-     *
-     *  @note
-     *      Does not check whether the object is actually obtained by the system layer instance associated with the Inet layer
-     *      instance. It merely tests whether \c aInetLayer is the Inet layer instance that was provided to \c InitInetLayerBasis.
-     */
     bool IsCreatedByInetLayer(const InetLayer & aInetLayer) const { return mInetLayer == &aInetLayer; }
 
     void * AppState;
 
 private:
-    InetLayer * mInetLayer; /**< Pointer to the InetLayer object that owns this object. */
-
-protected:
-    virtual ~EndPointBase() = default;
-
-    void InitEndPointBasis(InetLayer & aInetLayer, void * aAppState = nullptr)
-    {
-        AppState   = aAppState;
-        mInetLayer = &aInetLayer;
-        InitEndPointBasisImpl();
-    }
-
-    virtual void InitEndPointBasisImpl() = 0;
+    InetLayer * mInetLayer; /**< InetLayer object that owns this object. */
 };
 
 } // namespace Inet

src/inet/EndPointBasisImplLwIP.h

@@ -35,8 +35,9 @@ namespace Inet {
 class DLL_EXPORT EndPointImplLwIP : public EndPointBase
 {
 protected:
-    // EndPointBase overrides
-    void InitEndPointBasisImpl() override { mLwIPEndPointType = LwIPEndPointType::Unknown; }
+    EndPointImplLwIP(InetLayer & inetLayer, void * appState = nullptr) :
+        EndPointBase(inetLayer, appState), mLwIPEndPointType(LwIPEndPointType::Unknown)
+    {}
 
     /** Encapsulated LwIP protocol control block */
     union

src/inet/EndPointBasisImplNetworkFramework.h

@@ -34,7 +34,7 @@ namespace Inet {
 class DLL_EXPORT EndPointImplNetworkFramework : public EndPointBase
 {
 protected:
-    void InitEndPointBasisImpl() override {}
+    EndPointImplNetworkFramework(InetLayer & inetLayer, void * appState = nullptr) : EndPointBase(inetLayer, appState) {}
 
     nw_parameters_t mParameters;
     IPAddressType mAddrType; /**< Protocol family, i.e. IPv4 or IPv6. */

src/inet/EndPointBasisImplSockets.h

@@ -33,7 +33,9 @@ namespace Inet {
 class DLL_EXPORT EndPointImplSockets : public EndPointBase
 {
 protected:
-    void InitEndPointBasisImpl() override { mSocket = kInvalidSocketFd; }
+    EndPointImplSockets(InetLayer & inetLayer, void * appState = nullptr) :
+        EndPointBase(inetLayer, appState), mSocket(kInvalidSocketFd)
+    {}
 
     static constexpr int kInvalidSocketFd = -1;
     int mSocket;                     /**< Encapsulated socket descriptor. */

src/inet/InetLayer.cpp

@@ -429,7 +429,7 @@ CHIP_ERROR InetLayer::NewTCPEndPoint(TCPEndPoint ** retEndPoint)
 
     VerifyOrReturnError(mLayerState.IsInitialized(), CHIP_ERROR_INCORRECT_STATE);
 
-    *retEndPoint = TCPEndPoint::sPool.CreateObject();
+    *retEndPoint = TCPEndPoint::sPool.CreateObject(*this);
     if (*retEndPoint == nullptr)
     {
         ChipLogError(Inet, "%s endpoint pool FULL", "TCP");
@@ -469,7 +469,7 @@ CHIP_ERROR InetLayer::NewUDPEndPoint(UDPEndPoint ** retEndPoint)
 
     VerifyOrReturnError(mLayerState.IsInitialized(), CHIP_ERROR_INCORRECT_STATE);
 
-    *retEndPoint = UDPEndPoint::sPool.CreateObject();
+    *retEndPoint = UDPEndPoint::sPool.CreateObject(*this);
     if (*retEndPoint == nullptr)
     {
         ChipLogError(Inet, "%s endpoint pool FULL", "UDP");

src/inet/TCPEndPoint.cpp

@@ -2596,8 +2596,6 @@ bool TCPEndPoint::IsConnected(State state)
 
 void TCPEndPoint::Init(InetLayer * inetLayer)
 {
-    InitEndPointBasis(*inetLayer);
-
     mReceiveEnabled = true;
 
     // Initialize to zero for using system defaults.

src/inet/TCPEndPoint.h

@@ -74,7 +74,23 @@ class DLL_EXPORT TCPEndPoint : public EndPointBasis, public ReferenceCounted<TCP
     friend class TCPTest;
 
 public:
-    TCPEndPoint() = default;
+    TCPEndPoint(InetLayer & inetLayer, void * appState = nullptr) :
+        EndPointBasis(inetLayer, appState), mState(State::kReady), mReceiveEnabled(true),
+        mConnectTimeoutMsecs(0) // Initialize to zero for using system defaults.
+#if INET_CONFIG_OVERRIDE_SYSTEM_TCP_USER_TIMEOUT
+        ,
+        mUserTimeoutMillis(INET_CONFIG_DEFAULT_TCP_USER_TIMEOUT_MSEC), mUserTimeoutTimerRunning(false)
+#if INET_CONFIG_ENABLE_TCP_SEND_IDLE_CALLBACKS
+        ,
+        mIsTCPSendIdle(true), mTCPSendQueuePollPeriodMillis(INET_CONFIG_TCP_SEND_QUEUE_POLL_INTERVAL_MSEC),
+        mTCPSendQueueRemainingPollCount(
+            MaxTCPSendQueuePolls(INET_CONFIG_DEFAULT_TCP_USER_TIMEOUT_MSEC, INET_CONFIG_TCP_SEND_QUEUE_POLL_INTERVAL_MSEC)),
+        OnTCPSendIdleChanged(nullptr)
+#endif // INET_CONFIG_ENABLE_TCP_SEND_IDLE_CALLBACKS
+#endif // INET_CONFIG_OVERRIDE_SYSTEM_TCP_USER_TIMEOUT
+    {
+        InitImpl();
+    }
 
     /**
      * @brief   Bind the endpoint to an interface IP address.
@@ -644,13 +660,14 @@ class DLL_EXPORT TCPEndPoint : public EndPointBasis, public ReferenceCounted<TCP
     void ScheduleNextTCPUserTimeoutPoll(uint32_t aTimeOut);
 
 #if INET_CONFIG_ENABLE_TCP_SEND_IDLE_CALLBACKS
-    uint16_t MaxTCPSendQueuePolls(void)
+    static constexpr uint16_t MaxTCPSendQueuePolls(uint16_t userTimeout, uint16_t pollPeriod)
     {
         // If the UserTimeout is configured less than or equal to the poll interval,
         // return 1 to poll at least once instead of returning zero and timing out
         // immediately.
-        return (mUserTimeoutMillis > mTCPSendQueuePollPeriodMillis) ? (mUserTimeoutMillis / mTCPSendQueuePollPeriodMillis) : 1;
+        return (userTimeout > pollPeriod) ? (userTimeout / pollPeriod) : 1;
     }
+    uint16_t MaxTCPSendQueuePolls(void) { return MaxTCPSendQueuePolls(mUserTimeoutMillis, mTCPSendQueuePollPeriodMillis); }
 #endif // INET_CONFIG_ENABLE_TCP_SEND_IDLE_CALLBACKS
 
 #if CHIP_SYSTEM_CONFIG_USE_SOCKETS

src/inet/UDPEndPoint.cpp

@@ -2030,7 +2030,6 @@ void UDPEndPoint::Close()
 
 void UDPEndPoint::Init(InetLayer * inetLayer)
 {
-    InitEndPointBasis(*inetLayer);
     InitImpl();
 }
 

src/inet/UDPEndPoint.h

@@ -63,7 +63,7 @@ class UDPEndPointDeletor
 class DLL_EXPORT UDPEndPoint : public EndPointBasis, public ReferenceCounted<UDPEndPoint, UDPEndPointDeletor>
 {
 public:
-    UDPEndPoint() = default;
+    UDPEndPoint(InetLayer & inetLayer, void * appState = nullptr) : EndPointBasis(inetLayer, appState) { InitImpl(); }
 
     UDPEndPoint(const UDPEndPoint &) = delete;
     UDPEndPoint(UDPEndPoint &&)      = delete;