CoreFoundation: implement mapping from file descriptor to binary

This avoids an annoying warning in the Windows path that was introduced
with the last update to Foundation.  This implements the functionality
on Windows as well.

Author: compnerd

CoreFoundation/PlugIn.subproj/CFBundle_Internal.h

@@ -458,8 +458,29 @@ static bool _CFGetPathFromFileDescriptor(int fd, char *path) {
 #else
 
 static bool _CFGetPathFromFileDescriptor(int fd, char *path) {
-    #warning This platform does not have a way to go back from an open file descriptor to a path.
-    return false;
+    HANDLE hFile = _get_osfhandle(fd);
+    if (hFile == INVALID_HANDLE_VALUE)
+      return false;
+
+    DWORD dwLength = GetFinalPathNameByHandleW(hFile, NULL, 0, 0);
+
+    WCHAR *wszPath = (WCHAR *)malloc(dwLength);
+    if (wszPath == NULL)
+      return false;
+
+    if (GetFinalPathNameByHandleW(hFile, wszPath, dwLength, 0) != dwLength - 1) {
+      free(wszPath);
+      return false;
+    }
+
+    CFStringRef location =
+        CFStringCreateWithBytes(kCFAllocatorSystemDefault,
+                                (const UInt8 *)wszPath, dwLength - 1,
+                                kCFStringEncodingUTF16, false);
+    path = strdup(CFStringGetCStringPtr(location, kCFStringEncodingUTF8));
+    CFRelease(location);
+    free(wszPath);
+    return true;
 }
 
 #endif