InputStream: add virtual destructor

Replaces the method Close().

src/archive/plugins/Bzip2ArchivePlugin.cxx

@@ -61,7 +61,7 @@ public:
 	}
 
 	~Bzip2ArchiveFile() {
-		istream->Close();
+		delete istream;
 	}
 
 	void Ref() {
@@ -102,7 +102,6 @@ struct Bzip2InputStream final : public InputStream {
 	~Bzip2InputStream();
 
 	bool Open(Error &error);
-	void Close();
 };
 
 extern const InputPlugin bz2_inputplugin;
@@ -132,12 +131,6 @@ Bzip2InputStream::Open(Error &error)
 	return true;
 }
 
-inline void
-Bzip2InputStream::Close()
-{
-	BZ2_bzDecompressEnd(&bzstream);
-}
-
 /* archive open && listing routine */
 
 static ArchiveFile *
@@ -166,6 +159,7 @@ Bzip2InputStream::Bzip2InputStream(Bzip2ArchiveFile &_context,
 
 Bzip2InputStream::~Bzip2InputStream()
 {
+	BZ2_bzDecompressEnd(&bzstream);
 	archive->Unref();
 }
 
@@ -183,15 +177,6 @@ Bzip2ArchiveFile::OpenStream(const char *path,
 	return bis;
 }
 
-static void
-bz2_is_close(InputStream *is)
-{
-	Bzip2InputStream *bis = (Bzip2InputStream *)is;
-
-	bis->Close();
-	delete bis;
-}
-
 static bool
 bz2_fillbuffer(Bzip2InputStream *bis, Error &error)
 {
@@ -273,7 +258,6 @@ const InputPlugin bz2_inputplugin = {
 	nullptr,
 	nullptr,
 	nullptr,
-	bz2_is_close,
 	nullptr,
 	nullptr,
 	nullptr,

src/archive/plugins/Iso9660ArchivePlugin.cxx

@@ -181,14 +181,6 @@ Iso9660ArchiveFile::OpenStream(const char *pathname,
 				      statbuf);
 }
 
-static void
-iso9660_input_close(InputStream *is)
-{
-	Iso9660InputStream *iis = (Iso9660InputStream *)is;
-
-	delete iis;
-}
-
 inline size_t
 Iso9660InputStream::Read(void *ptr, size_t read_size, Error &error)
 {
@@ -250,7 +242,6 @@ const InputPlugin iso9660_input_plugin = {
 	nullptr,
 	nullptr,
 	nullptr,
-	iso9660_input_close,
 	nullptr,
 	nullptr,
 	nullptr,

src/archive/plugins/ZzipArchivePlugin.cxx

@@ -142,14 +142,6 @@ ZzipArchiveFile::OpenStream(const char *pathname,
 				   _file);
 }
 
-static void
-zzip_input_close(InputStream *is)
-{
-	ZzipInputStream *zis = (ZzipInputStream *)is;
-
-	delete zis;
-}
-
 static size_t
 zzip_input_read(InputStream *is, void *ptr, size_t size,
 		Error &error)
@@ -202,7 +194,6 @@ const InputPlugin zzip_input_plugin = {
 	nullptr,
 	nullptr,
 	nullptr,
-	zzip_input_close,
 	nullptr,
 	nullptr,
 	nullptr,