InputStream: add virtual destructor

Replaces the method Close().

src/input/ThreadInputStream.cxx

@@ -29,6 +29,15 @@
 
 ThreadInputStream::~ThreadInputStream()
 {
+	Lock();
+	close = true;
+	wake_cond.signal();
+	Unlock();
+
+	Cancel();
+
+	thread.Join();
+
 	if (buffer != nullptr) {
 		buffer->Clear();
 		HugeFree(buffer->Write().data, buffer_size);
@@ -172,28 +181,6 @@ ThreadInputStream::Read(InputStream *is, void *ptr, size_t size,
 	return tis.Read2(ptr, size, error);
 }
 
-inline void
-ThreadInputStream::Close2()
-{
-	Lock();
-	close = true;
-	wake_cond.signal();
-	Unlock();
-
-	Cancel();
-
-	thread.Join();
-
-	delete this;
-}
-
-void
-ThreadInputStream::Close(InputStream *is)
-{
-	ThreadInputStream &tis = *(ThreadInputStream *)is;
-	tis.Close2();
-}
-
 inline bool
 ThreadInputStream::IsEOF2()
 {