From 67a824607797706f2058aa70fb629f0589a90103 Mon Sep 17 00:00:00 2001
From: Jean-Baptiste Perrier <jeanbapt.perrier@gmail.com>
Date: Mon, 25 Jan 2021 17:54:16 +0100
Subject: [PATCH] Revamp IsReadable & IsWriteable.

---
 Source/Engine/Platform/Base/NetworkBase.cpp   |  7 +++-
 Source/Engine/Platform/Base/NetworkBase.h     |  3 +-
 Source/Engine/Platform/Win32/Win32Network.cpp | 42 ++++++++++++++++---
 Source/Engine/Platform/Win32/Win32Network.h   |  3 +-
 4 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/Source/Engine/Platform/Base/NetworkBase.cpp b/Source/Engine/Platform/Base/NetworkBase.cpp
index 73b649281..e7b700911 100644
--- a/Source/Engine/Platform/Base/NetworkBase.cpp
+++ b/Source/Engine/Platform/Base/NetworkBase.cpp
@@ -61,11 +61,16 @@ bool NetworkBase::Accept(NetworkSocket& serverSock, NetworkSocket& newSock, Netw
     return false;
 }
 
-bool NetworkBase::IsReadable(NetworkSocket& socket, uint64* size)
+bool NetworkBase::IsReadable(NetworkSocket& socket)
 {
     return false;
 }
 
+bool NetworkBase::IsWriteable(NetworkSocket& socket)
+{
+    return true;
+}
+
 int32 NetworkBase::WriteSocket(NetworkSocket socket, byte* data, uint32 length, NetworkEndPoint* endPoint)
 {
     return 0;
diff --git a/Source/Engine/Platform/Base/NetworkBase.h b/Source/Engine/Platform/Base/NetworkBase.h
index a568fd215..295100ffe 100644
--- a/Source/Engine/Platform/Base/NetworkBase.h
+++ b/Source/Engine/Platform/Base/NetworkBase.h
@@ -69,7 +69,8 @@ class FLAXENGINE_API NetworkBase
     static bool BindSocket(NetworkSocket& socket, NetworkEndPoint& endPoint);
     static bool Listen(NetworkSocket& socket, uint16 queueSize);
     static bool Accept(NetworkSocket& serverSock, NetworkSocket& newSock, NetworkEndPoint& newEndPoint);
-    static bool IsReadable(NetworkSocket& socket, uint64* size);
+    static bool IsReadable(NetworkSocket& socket);
+    static bool IsWriteable(NetworkSocket& socket);
     static int32 WriteSocket(NetworkSocket socket, byte* data, uint32 length, NetworkEndPoint* endPoint = nullptr);
     static int32 ReadSocket(NetworkSocket socket, byte* buffer, uint32 bufferSize, NetworkEndPoint* endPoint = nullptr);
     static bool CreateEndPoint(String* address, String* port, NetworkIPVersion ipv, NetworkEndPoint& endPoint, bool bindable = false);
diff --git a/Source/Engine/Platform/Win32/Win32Network.cpp b/Source/Engine/Platform/Win32/Win32Network.cpp
index 77c0baf4d..e0f82de6b 100644
--- a/Source/Engine/Platform/Win32/Win32Network.cpp
+++ b/Source/Engine/Platform/Win32/Win32Network.cpp
@@ -288,15 +288,45 @@ bool Win32Network::Accept(NetworkSocket& serverSock, NetworkSocket& newSock, Net
     return false;
 }
 
-bool Win32Network::IsReadable(NetworkSocket& socket, uint64* size)
+bool Win32Network::IsReadable(NetworkSocket& socket)
 {
-    unsigned long value;
-    if (ioctlsocket(*(SOCKET*)socket.Data, FIONREAD, &value) != 0)
+    fd_set readfds;
+    FD_ZERO(&readfds);
+    FD_SET(*(SOCKET*)socket.Data, &readfds);
+    timeval t;
+    t.tv_sec = 0;
+    t.tv_usec = 0;
+    if (select(0, &readfds, nullptr, nullptr, &t) == SOCKET_ERROR)
     {
-        LOG(Error, "Unable to query socket for readability! Socket : {0} Error : {1}", *(SOCKET*)socket.Data, GetLastErrorMessage().Get());
-        return true;
+        int error = WSAGetLastError();
+        if (error == WSAEWOULDBLOCK)
+            return false;
+        LOG(Error, "Unable to check readability of socket! Socket : {0} Error : {1}", *(SOCKET*)socket.Data, GetErrorMessage(error).Get());
+        return false;
     }
-    *size = value;
+    if (FD_ISSET(*(SOCKET*)socket.Data, &readfds))
+        return true;
+    return false;
+}
+
+bool Win32Network::IsWriteable(NetworkSocket& socket)
+{
+    fd_set writefds;
+    FD_ZERO(&writefds);
+    FD_SET(*(SOCKET*)socket.Data, &writefds);
+    timeval t;
+    t.tv_sec = 0;
+    t.tv_usec = 0;
+    if (select(0, nullptr, &writefds, nullptr, &t) == SOCKET_ERROR)
+    {
+        int error = WSAGetLastError();
+        if (error == WSAEWOULDBLOCK)
+            return false;
+        LOG(Error, "Unable to check writeability of socket! Socket : {0} Error : {1}", *(SOCKET*)socket.Data, GetErrorMessage(error).Get());
+        return false;
+    }
+    if (FD_ISSET(*(SOCKET*)socket.Data, &writefds))
+        return true;
     return false;
 }
 
diff --git a/Source/Engine/Platform/Win32/Win32Network.h b/Source/Engine/Platform/Win32/Win32Network.h
index 8cbcf57ec..bbf15a4c4 100644
--- a/Source/Engine/Platform/Win32/Win32Network.h
+++ b/Source/Engine/Platform/Win32/Win32Network.h
@@ -25,7 +25,8 @@ public:
     static bool BindSocket(NetworkSocket& socket, NetworkEndPoint& endPoint);
     static bool Listen(NetworkSocket& socket, uint16 queueSize);
     static bool Accept(NetworkSocket& serverSock, NetworkSocket& newSock, NetworkEndPoint& newEndPoint);
-    static bool IsReadable(NetworkSocket& socket, uint64* size);
+    static bool IsReadable(NetworkSocket& socket);
+    static bool IsWriteable(NetworkSocket& socket);
     static int32 WriteSocket(NetworkSocket socket, byte* data, uint32 length, NetworkEndPoint* endPoint = nullptr);
     static int32 ReadSocket(NetworkSocket socket, byte* buffer, uint32 bufferSize, NetworkEndPoint* endPoint = nullptr);
     static bool CreateEndPoint(String* address, String* port, NetworkIPVersion ipv, NetworkEndPoint& endPoint, bool bindable = false);