Networking (Windows): print readable error message

Author: CarterLi

CMakeLists.txt

@@ -1034,6 +1034,7 @@ elseif(WIN32)
         src/util/windows/version.c
         src/util/platform/FFPlatform_windows.c
         src/util/binary_windows.c
+        src/util/debug_windows.c
     )
 elseif(SunOS)
     list(APPEND LIBFASTFETCH_SRC

src/common/networking/networking_windows.c

@@ -109,7 +109,7 @@ const char* ffNetworkingSendHttpRequest(FFNetworkingState* state, const char* ho
     #ifdef TCP_NODELAY
     // Enable TCP_NODELAY to disable Nagle's algorithm
     if (setsockopt(state->sockfd, IPPROTO_TCP, TCP_NODELAY, (char*)&flag, sizeof(flag)) != 0) {
-        FF_DEBUG("Failed to set TCP_NODELAY: %d", WSAGetLastError());
+        FF_DEBUG("Failed to set TCP_NODELAY: %s", ffDebugWin32Error((DWORD) WSAGetLastError()));
     } else {
         FF_DEBUG("Successfully disabled Nagle's algorithm");
     }
@@ -118,7 +118,7 @@ const char* ffNetworkingSendHttpRequest(FFNetworkingState* state, const char* ho
     #ifdef TCP_FASTOPEN
     // Set TCP Fast Open
     if (setsockopt(state->sockfd, IPPROTO_TCP, TCP_FASTOPEN, (char*)&flag, sizeof(flag)) != 0) {
-        FF_DEBUG("Failed to set TCP_FASTOPEN option: %d", WSAGetLastError());
+        FF_DEBUG("Failed to set TCP_FASTOPEN option: %s", ffDebugWin32Error((DWORD) WSAGetLastError()));
     } else {
         FF_DEBUG("Successfully set TCP_FASTOPEN option");
     }
@@ -141,7 +141,7 @@ const char* ffNetworkingSendHttpRequest(FFNetworkingState* state, const char* ho
             .sin_addr.s_addr = INADDR_ANY,
         }, sizeof(struct sockaddr_in))) != 0)
     {
-        FF_DEBUG("bind() failed: %d", WSAGetLastError());
+        FF_DEBUG("bind() failed: %s", ffDebugWin32Error((DWORD) WSAGetLastError()));
         closesocket(state->sockfd);
         freeaddrinfo(addr);
         state->sockfd = INVALID_SOCKET;
@@ -177,7 +177,7 @@ const char* ffNetworkingSendHttpRequest(FFNetworkingState* state, const char* ho
 
     if(!result && WSAGetLastError() != WSA_IO_PENDING)
     {
-        FF_DEBUG("ConnectEx() failed: %d", WSAGetLastError());
+        FF_DEBUG("ConnectEx() failed: %s", ffDebugWin32Error((DWORD) WSAGetLastError()));
         closesocket(state->sockfd);
         state->sockfd = INVALID_SOCKET;
         return "ConnectEx() failed";
@@ -213,7 +213,7 @@ const char* ffNetworkingRecvHttpResponse(FFNetworkingState* state, FFstrbuf* buf
     DWORD transfer, flags;
     if (!WSAGetOverlappedResult(state->sockfd, &state->overlapped, &transfer, TRUE, &flags))
     {
-        FF_DEBUG("WSAGetOverlappedResult failed: %d", WSAGetLastError());
+        FF_DEBUG("WSAGetOverlappedResult failed: %s", ffDebugWin32Error((DWORD) WSAGetLastError()));
         closesocket(state->sockfd);
         return "WSAGetOverlappedResult() failed";
     }
@@ -243,7 +243,7 @@ const char* ffNetworkingRecvHttpResponse(FFNetworkingState* state, FFstrbuf* buf
             if (received == 0) {
                 FF_DEBUG("Connection closed (received=0)");
             } else {
-                FF_DEBUG("Reception failed: %d", WSAGetLastError());
+                FF_DEBUG("Reception failed: %s", ffDebugWin32Error((DWORD) WSAGetLastError()));
             }
             break;
         }

src/util/debug.h

@@ -24,3 +24,5 @@ static inline const char* ffFindFileName(const char* file)
 #endif
 
 #define FF_DEBUG(format, ...) FF_DEBUG_PRINT(__FILE__, __LINE__, format, ##__VA_ARGS__)
+
+const char* ffDebugWin32Error(unsigned long errorCode);

src/util/debug_windows.c

@@ -0,0 +1,28 @@
+#include "debug.h"
+
+#include <windows.h>
+
+const char* ffDebugWin32Error(DWORD errorCode)
+{
+    static char buffer[256];
+
+    DWORD len = FormatMessageA(
+        FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+        NULL,
+        (DWORD) errorCode,
+        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+        buffer,
+        sizeof(buffer),
+        NULL);
+
+    if (len == 0) {
+        snprintf(buffer, sizeof(buffer), "Unknown error code (%lu)", errorCode);
+    } else {
+        // Remove trailing newline
+        if (buffer[len - 1] == '\n') buffer[len - 1] = '\0';
+        if (buffer[len - 2] == '\r') buffer[len - 2] = '\0';
+        snprintf(buffer + len - 2, sizeof(buffer) - len + 2, " (%lu)", errorCode);
+    }
+
+    return buffer;
+}