InputStream: make various methods abstract

Replace InputPlugin attributes.

19 files changed, 252 insertions, 643 deletions

diff --git a/src/archive/plugins/Bzip2ArchivePlugin.cxx b/src/archive/plugins/Bzip2ArchivePlugin.cxx
index 213b7d38c..d349b537f 100644
--- a/src/archive/plugins/Bzip2ArchivePlugin.cxx
+++ b/src/archive/plugins/Bzip2ArchivePlugin.cxx
@@ -102,6 +102,10 @@ struct Bzip2InputStream final : public InputStream {
 	~Bzip2InputStream();
 
 	bool Open(Error &error);
+
+	/* virtual methods from InputStream */
+	bool IsEOF() override;
+	size_t Read(void *ptr, size_t size, Error &error) override;
 };
 
 extern const InputPlugin bz2_inputplugin;
@@ -198,30 +202,26 @@ bz2_fillbuffer(Bzip2InputStream *bis, Error &error)
 	return true;
 }
 
-static size_t
-bz2_is_read(InputStream *is, void *ptr, size_t length,
-	    Error &error)
+size_t
+Bzip2InputStream::Read(void *ptr, size_t length, Error &error)
 {
-	Bzip2InputStream *bis = (Bzip2InputStream *)is;
-	bz_stream *bzstream;
 	int bz_result;
 	size_t nbytes = 0;
 
-	if (bis->eof)
+	if (eof)
 		return 0;
 
-	bzstream = &bis->bzstream;
-	bzstream->next_out = (char *)ptr;
-	bzstream->avail_out = length;
+	bzstream.next_out = (char *)ptr;
+	bzstream.avail_out = length;
 
 	do {
-		if (!bz2_fillbuffer(bis, error))
+		if (!bz2_fillbuffer(this, error))
 			return 0;
 
-		bz_result = BZ2_bzDecompress(bzstream);
+		bz_result = BZ2_bzDecompress(&bzstream);
 
 		if (bz_result == BZ_STREAM_END) {
-			bis->eof = true;
+			eof = true;
 			break;
 		}
 
@@ -230,20 +230,18 @@ bz2_is_read(InputStream *is, void *ptr, size_t length,
 				  "BZ2_bzDecompress() has failed");
 			return 0;
 		}
-	} while (bzstream->avail_out == length);
+	} while (bzstream.avail_out == length);
 
-	nbytes = length - bzstream->avail_out;
-	is->offset += nbytes;
+	nbytes = length - bzstream.avail_out;
+	offset += nbytes;
 
 	return nbytes;
 }
 
-static bool
-bz2_is_eof(InputStream *is)
+bool
+Bzip2InputStream::IsEOF()
 {
-	Bzip2InputStream *bis = (Bzip2InputStream *)is;
-
-	return bis->eof;
+	return eof;
 }
 
 /* exported structures */
@@ -258,13 +256,6 @@ const InputPlugin bz2_inputplugin = {
 	nullptr,
 	nullptr,
 	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	bz2_is_read,
-	bz2_is_eof,
-	nullptr,
 };
 
 const ArchivePlugin bz2_archive_plugin = {
diff --git a/src/archive/plugins/Iso9660ArchivePlugin.cxx b/src/archive/plugins/Iso9660ArchivePlugin.cxx
index 0a9cb8214..e5c3fd062 100644
--- a/src/archive/plugins/Iso9660ArchivePlugin.cxx
+++ b/src/archive/plugins/Iso9660ArchivePlugin.cxx
@@ -162,7 +162,9 @@ public:
 		archive.Unref();
 	}
 
-	size_t Read(void *ptr, size_t size, Error &error);
+	/* virtual methods from InputStream */
+	bool IsEOF() override;
+	size_t Read(void *ptr, size_t size, Error &error) override;
 };
 
 InputStream *
@@ -181,7 +183,7 @@ Iso9660ArchiveFile::OpenStream(const char *pathname,
 				      statbuf);
 }
 
-inline size_t
+size_t
 Iso9660InputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	int readed = 0;
@@ -216,18 +218,10 @@ Iso9660InputStream::Read(void *ptr, size_t read_size, Error &error)
 	return readed;
 }
 
-static size_t
-iso9660_input_read(InputStream *is, void *ptr, size_t size,
-		   Error &error)
+bool
+Iso9660InputStream::IsEOF()
 {
-	Iso9660InputStream *iis = (Iso9660InputStream *)is;
-	return iis->Read(ptr, size, error);
-}
-
-static bool
-iso9660_input_eof(InputStream *is)
-{
-	return is->offset == is->size;
+	return offset == size;
 }
 
 /* exported structures */
@@ -242,13 +236,6 @@ const InputPlugin iso9660_input_plugin = {
 	nullptr,
 	nullptr,
 	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	iso9660_input_read,
-	iso9660_input_eof,
-	nullptr,
 };
 
 const ArchivePlugin iso9660_archive_plugin = {
diff --git a/src/archive/plugins/ZzipArchivePlugin.cxx b/src/archive/plugins/ZzipArchivePlugin.cxx
index 4eafe4aeb..53b6b9f93 100644
--- a/src/archive/plugins/ZzipArchivePlugin.cxx
+++ b/src/archive/plugins/ZzipArchivePlugin.cxx
@@ -123,6 +123,11 @@ struct ZzipInputStream final : public InputStream {
 		zzip_file_close(file);
 		archive->Unref();
 	}
+
+	/* virtual methods from InputStream */
+	bool IsEOF() override;
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
 };
 
 InputStream *
@@ -142,41 +147,32 @@ ZzipArchiveFile::OpenStream(const char *pathname,
 				   _file);
 }
 
-static size_t
-zzip_input_read(InputStream *is, void *ptr, size_t size,
-		Error &error)
+size_t
+ZzipInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
-	ZzipInputStream *zis = (ZzipInputStream *)is;
-	int ret;
-
-	ret = zzip_file_read(zis->file, ptr, size);
+	int ret = zzip_file_read(file, ptr, read_size);
 	if (ret < 0) {
 		error.Set(zzip_domain, "zzip_file_read() has failed");
 		return 0;
 	}
 
-	is->offset = zzip_tell(zis->file);
-
+	offset = zzip_tell(file);
 	return ret;
 }
 
-static bool
-zzip_input_eof(InputStream *is)
+bool
+ZzipInputStream::IsEOF()
 {
-	ZzipInputStream *zis = (ZzipInputStream *)is;
-
-	return (InputPlugin::offset_type)zzip_tell(zis->file) == is->size;
+	return (InputPlugin::offset_type)zzip_tell(file) == size;
 }
 
-static bool
-zzip_input_seek(InputStream *is, InputPlugin::offset_type offset,
-		int whence, Error &error)
+bool
+ZzipInputStream::Seek(offset_type new_offset, int whence, Error &error)
 {
-	ZzipInputStream *zis = (ZzipInputStream *)is;
-	zzip_off_t ofs = zzip_seek(zis->file, offset, whence);
+	zzip_off_t ofs = zzip_seek(file, new_offset, whence);
 	if (ofs != -1) {
 		error.Set(zzip_domain, "zzip_seek() has failed");
-		is->offset = ofs;
+		offset = ofs;
 		return true;
 	}
 	return false;
@@ -194,13 +190,6 @@ const InputPlugin zzip_input_plugin = {
 	nullptr,
 	nullptr,
 	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	zzip_input_read,
-	zzip_input_eof,
-	zzip_input_seek,
 };
 
 const ArchivePlugin zzip_archive_plugin = {
diff --git a/src/input/InputPlugin.hxx b/src/input/InputPlugin.hxx
index 449604434..1bdf44b77 100644
--- a/src/input/InputPlugin.hxx
+++ b/src/input/InputPlugin.hxx
@@ -82,38 +82,6 @@ struct InputPlugin {
 	InputStream *(*open)(const char *uri,
 			     Mutex &mutex, Cond &cond,
 			     Error &error);
-
-	/**
-	 * Check for errors that may have occurred in the I/O thread.
-	 * May be unimplemented for synchronous plugins.
-	 *
-	 * @return false on error
-	 */
-	bool (*check)(InputStream *is, Error &error);
-
-	/**
-	 * Update the public attributes.  Call before access.  Can be
-	 * nullptr if the plugin always keeps its attributes up to date.
-	 */
-	void (*update)(InputStream *is);
-
-	Tag *(*tag)(InputStream *is);
-
-	/**
-	 * Returns true if the next read operation will not block:
-	 * either data is available, or end-of-stream has been
-	 * reached, or an error has occurred.
-	 *
-	 * If this method is unimplemented, then it is assumed that
-	 * reading will never block.
-	 */
-	bool (*available)(InputStream *is);
-
-	size_t (*read)(InputStream *is, void *ptr, size_t size,
-		       Error &error);
-	bool (*eof)(InputStream *is);
-	bool (*seek)(InputStream *is, offset_type offset, int whence,
-		     Error &error);
 };
 
 #endif
diff --git a/src/input/InputStream.cxx b/src/input/InputStream.cxx
index 2e0df6856..d4f1b1f87 100644
--- a/src/input/InputStream.cxx
+++ b/src/input/InputStream.cxx
@@ -45,10 +45,6 @@ InputStream::Open(const char *url,
 
 		is = plugin->open(url, mutex, cond, error);
 		if (is != nullptr) {
-			assert(is->plugin.read != nullptr);
-			assert(is->plugin.eof != nullptr);
-			assert(!is->seekable || is->plugin.seek != nullptr);
-
 			is = input_rewind_open(is);
 
 			return is;
@@ -83,16 +79,14 @@ InputStream::OpenReady(const char *uri,
 }
 
 bool
-InputStream::Check(Error &error)
+InputStream::Check(gcc_unused Error &error)
 {
-	return plugin.check == nullptr || plugin.check(this, error);
+	return true;
 }
 
 void
 InputStream::Update()
 {
-	if (plugin.update != nullptr)
-		plugin.update(this);
 }
 
 void
@@ -130,20 +124,15 @@ InputStream::CheapSeeking() const
 }
 
 bool
-InputStream::Seek(offset_type _offset, int whence, Error &error)
+InputStream::Seek(gcc_unused offset_type new_offset, gcc_unused int whence,
+		  gcc_unused Error &error)
 {
-	if (plugin.seek == nullptr)
-		return false;
-
-	return plugin.seek(this, _offset, whence, error);
+	return false;
 }
 
 bool
 InputStream::LockSeek(offset_type _offset, int whence, Error &error)
 {
-	if (plugin.seek == nullptr)
-		return false;
-
 	const ScopeLock protect(mutex);
 	return Seek(_offset, whence, error);
 }
@@ -163,17 +152,12 @@ InputStream::LockRewind(Error &error)
 Tag *
 InputStream::ReadTag()
 {
-	return plugin.tag != nullptr
-		? plugin.tag(this)
-		: nullptr;
+	return nullptr;
 }
 
 Tag *
 InputStream::LockReadTag()
 {
-	if (plugin.tag == nullptr)
-		return nullptr;
-
 	const ScopeLock protect(mutex);
 	return ReadTag();
 }
@@ -181,18 +165,7 @@ InputStream::LockReadTag()
 bool
 InputStream::IsAvailable()
 {
-	return plugin.available != nullptr
-		? plugin.available(this)
-		: true;
-}
-
-size_t
-InputStream::Read(void *ptr, size_t _size, Error &error)
-{
-	assert(ptr != nullptr);
-	assert(_size > 0);
-
-	return plugin.read(this, ptr, _size, error);
+	return true;
 }
 
 size_t
@@ -206,12 +179,6 @@ InputStream::LockRead(void *ptr, size_t _size, Error &error)
 }
 
 bool
-InputStream::IsEOF()
-{
-	return plugin.eof(this);
-}
-
-bool
 InputStream::LockIsEOF()
 {
 	const ScopeLock protect(mutex);
diff --git a/src/input/InputStream.hxx b/src/input/InputStream.hxx
index 4a9d7832a..b1f8c0d8c 100644
--- a/src/input/InputStream.hxx
+++ b/src/input/InputStream.hxx
@@ -166,13 +166,13 @@ public:
 	 *
 	 * @return false on error
 	 */
-	bool Check(Error &error);
+	virtual bool Check(Error &error);
 
 	/**
 	 * Update the public attributes.  Call before accessing attributes
 	 * such as "ready" or "offset".
 	 */
-	void Update();
+	virtual void Update();
 
 	void SetReady();
 
@@ -272,7 +272,7 @@ public:
 	 * @param offset the relative offset
 	 * @param whence the base of the seek, one of SEEK_SET, SEEK_CUR, SEEK_END
 	 */
-	bool Seek(offset_type offset, int whence, Error &error);
+	virtual bool Seek(offset_type offset, int whence, Error &error);
 
 	/**
 	 * Wrapper for Seek() which locks and unlocks the mutex; the
@@ -293,7 +293,7 @@ public:
 	 * The caller must lock the mutex.
 	 */
 	gcc_pure
-	bool IsEOF();
+	virtual bool IsEOF() = 0;
 
 	/**
 	 * Wrapper for IsEOF() which locks and unlocks the mutex; the
@@ -311,7 +311,7 @@ public:
 	 * nullptr if the tag has not changed since the last call
 	 */
 	gcc_malloc
-	Tag *ReadTag();
+	virtual Tag *ReadTag();
 
 	/**
 	 * Wrapper for ReadTag() which locks and unlocks the mutex;
@@ -328,7 +328,7 @@ public:
 	 * The caller must lock the mutex.
 	 */
 	gcc_pure
-	bool IsAvailable();
+	virtual bool IsAvailable();
 
 	/**
 	 * Reads data from the stream into the caller-supplied buffer.
@@ -342,7 +342,7 @@ public:
 	 * @return the number of bytes read
 	 */
 	gcc_nonnull_all
-	size_t Read(void *ptr, size_t size, Error &error);
+	virtual size_t Read(void *ptr, size_t size, Error &error) = 0;
 
 	/**
 	 * Wrapper for Read() which locks and unlocks the mutex;
diff --git a/src/input/ThreadInputStream.cxx b/src/input/ThreadInputStream.cxx
index 408b757f9..efbb8c9f9 100644
--- a/src/input/ThreadInputStream.cxx
+++ b/src/input/ThreadInputStream.cxx
@@ -116,8 +116,8 @@ ThreadInputStream::ThreadFunc(void *ctx)
 	tis.ThreadFunc();
 }
 
-inline bool
-ThreadInputStream::Check2(Error &error)
+bool
+ThreadInputStream::Check(Error &error)
 {
 	if (postponed_error.IsDefined()) {
 		error = std::move(postponed_error);
@@ -128,27 +128,13 @@ ThreadInputStream::Check2(Error &error)
 }
 
 bool
-ThreadInputStream::Check(InputStream *is, Error &error)
-{
-	ThreadInputStream &tis = *(ThreadInputStream *)is;
-	return tis.Check2(error);
-}
-
-inline bool
-ThreadInputStream::Available2()
+ThreadInputStream::IsAvailable()
 {
 	return !buffer->IsEmpty() || eof || postponed_error.IsDefined();
 }
 
-bool
-ThreadInputStream::Available(InputStream *is)
-{
-	ThreadInputStream &tis = *(ThreadInputStream *)is;
-	return tis.Available2();
-}
-
 inline size_t
-ThreadInputStream::Read2(void *ptr, size_t read_size, Error &error)
+ThreadInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	while (true) {
 		if (postponed_error.IsDefined()) {
@@ -173,23 +159,8 @@ ThreadInputStream::Read2(void *ptr, size_t read_size, Error &error)
 	}
 }
 
-size_t
-ThreadInputStream::Read(InputStream *is, void *ptr, size_t size,
-			Error &error)
-{
-	ThreadInputStream &tis = *(ThreadInputStream *)is;
-	return tis.Read2(ptr, size, error);
-}
-
-inline bool
-ThreadInputStream::IsEOF2()
-{
-	return eof;
-}
-
 bool
-ThreadInputStream::IsEOF(InputStream *is)
+ThreadInputStream::IsEOF()
 {
-	ThreadInputStream &tis = *(ThreadInputStream *)is;
-	return tis.IsEOF2();
+	return eof;
 }
diff --git a/src/input/ThreadInputStream.hxx b/src/input/ThreadInputStream.hxx
index 2354000f6..4d4ec3972 100644
--- a/src/input/ThreadInputStream.hxx
+++ b/src/input/ThreadInputStream.hxx
@@ -82,6 +82,12 @@ public:
 	 */
 	InputStream *Start(Error &error);
 
+	/* virtual methods from InputStream */
+	bool Check(Error &error) override final;
+	bool IsEOF() override final;
+	bool IsAvailable() override final;
+	size_t Read(void *ptr, size_t size, Error &error) override final;
+
 protected:
 	void SetMimeType(const char *_mime) {
 		assert(thread.IsInside());
@@ -110,7 +116,7 @@ protected:
 	 *
 	 * @return 0 on end-of-file or on error
 	 */
-	virtual size_t Read(void *ptr, size_t size, Error &error) = 0;
+	virtual size_t ThreadRead(void *ptr, size_t size, Error &error) = 0;
 
 	/**
 	 * Optional deinitialization before leaving the thread.
@@ -130,19 +136,6 @@ protected:
 private:
 	void ThreadFunc();
 	static void ThreadFunc(void *ctx);
-
-	bool Check2(Error &error);
-	bool Available2();
-	size_t Read2(void *ptr, size_t size, Error &error);
-	bool IsEOF2();
-
-public:
-	/* InputPlugin callbacks */
-	static bool Check(InputStream *is, Error &error);
-	static bool Available(InputStream *is);
-	static size_t Read(InputStream *is, void *ptr, size_t size,
-			   Error &error);
-	static bool IsEOF(InputStream *is);
 };
 
 #endif
diff --git a/src/input/plugins/AlsaInputPlugin.cxx b/src/input/plugins/AlsaInputPlugin.cxx
index 2049c5635..b4673afcf 100644
--- a/src/input/plugins/AlsaInputPlugin.cxx
+++ b/src/input/plugins/AlsaInputPlugin.cxx
@@ -116,7 +116,13 @@ public:
 	static InputStream *Create(const char *uri, Mutex &mutex, Cond &cond,
 				   Error &error);
 
-	bool Available() {
+	/* virtual methods from InputStream */
+
+	bool IsEOF() override {
+		return eof;
+	}
+
+	bool IsAvailable() override {
 		if (snd_pcm_avail(capture_handle) > frames_to_read)
 			return true;
 
@@ -126,11 +132,7 @@ public:
 		return false;
 	}
 
-	size_t Read(void *ptr, size_t size, Error &error);
-
-	bool IsEOF() {
-		return eof;
-	}
+	size_t Read(void *ptr, size_t size, Error &error) override;
 
 private:
 	static snd_pcm_t *OpenDevice(const char *device, int rate,
@@ -181,7 +183,7 @@ AlsaInputStream::Create(const char *uri, Mutex &mutex, Cond &cond,
 				   handle, frame_size);
 }
 
-inline size_t
+size_t
 AlsaInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	assert(ptr != nullptr);
@@ -373,37 +375,9 @@ alsa_input_open(const char *uri, Mutex &mutex, Cond &cond, Error &error)
 	return AlsaInputStream::Create(uri, mutex, cond, error);
 }
 
-static bool
-alsa_input_available(InputStream *is)
-{
-	AlsaInputStream *ais = (AlsaInputStream *)is;
-	return ais->Available();
-}
-
-static size_t
-alsa_input_read(InputStream *is, void *ptr, size_t size, Error &error)
-{
-	AlsaInputStream *ais = (AlsaInputStream *)is;
-	return ais->Read(ptr, size, error);
-}
-
-static bool
-alsa_input_eof(gcc_unused InputStream *is)
-{
-	AlsaInputStream *ais = (AlsaInputStream *)is;
-	return ais->IsEOF();
-}
-
 const struct InputPlugin input_plugin_alsa = {
 	"alsa",
 	nullptr,
 	nullptr,
 	alsa_input_open,
-	nullptr,
-	nullptr,
-	nullptr,
-	alsa_input_available,
-	alsa_input_read,
-	alsa_input_eof,
-	nullptr,
 };
diff --git a/src/input/plugins/ArchiveInputPlugin.cxx b/src/input/plugins/ArchiveInputPlugin.cxx
index 8a8be5b2f..b51dc6835 100644
--- a/src/input/plugins/ArchiveInputPlugin.cxx
+++ b/src/input/plugins/ArchiveInputPlugin.cxx
@@ -89,11 +89,4 @@ const InputPlugin input_plugin_archive = {
 	nullptr,
 	nullptr,
 	input_archive_open,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
 };
diff --git a/src/input/plugins/CdioParanoiaInputPlugin.cxx b/src/input/plugins/CdioParanoiaInputPlugin.cxx
index c5b238320..a5c848f68 100644
--- a/src/input/plugins/CdioParanoiaInputPlugin.cxx
+++ b/src/input/plugins/CdioParanoiaInputPlugin.cxx
@@ -79,6 +79,11 @@ struct CdioParanoiaInputStream final : public InputStream {
 		if (cdio != nullptr)
 			cdio_destroy(cdio);
 	}
+
+	/* virtual methods from InputStream */
+	bool IsEOF() override;
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
 };
 
 static constexpr Domain cdio_domain("cdio");
@@ -266,48 +271,44 @@ input_cdio_open(const char *uri,
 	return i;
 }
 
-static bool
-input_cdio_seek(InputStream *is,
-		InputPlugin::offset_type offset, int whence, Error &error)
+bool
+CdioParanoiaInputStream::Seek(InputPlugin::offset_type new_offset,
+			      int whence, Error &error)
 {
-	CdioParanoiaInputStream *cis = (CdioParanoiaInputStream *)is;
-
 	/* calculate absolute offset */
 	switch (whence) {
 	case SEEK_SET:
 		break;
 	case SEEK_CUR:
-		offset += cis->offset;
+		new_offset += offset;
 		break;
 	case SEEK_END:
-		offset += cis->size;
+		new_offset += size;
 		break;
 	}
 
-	if (offset < 0 || offset > cis->size) {
+	if (new_offset < 0 || new_offset > size) {
 		error.Format(cdio_domain, "Invalid offset to seek %ld (%ld)",
-			     (long int)offset, (long int)cis->size);
+			     (long int)new_offset, (long int)size);
 		return false;
 	}
 
 	/* simple case */
-	if (offset == cis->offset)
+	if (new_offset == offset)
 		return true;
 
 	/* calculate current LSN */
-	cis->lsn_relofs = offset / CDIO_CD_FRAMESIZE_RAW;
-	cis->offset = offset;
+	lsn_relofs = new_offset / CDIO_CD_FRAMESIZE_RAW;
+	offset = new_offset;
 
-	cdio_paranoia_seek(cis->para, cis->lsn_from + cis->lsn_relofs, SEEK_SET);
+	cdio_paranoia_seek(para, lsn_from + lsn_relofs, SEEK_SET);
 
 	return true;
 }
 
-static size_t
-input_cdio_read(InputStream *is, void *ptr, size_t length,
-		Error &error)
+size_t
+CdioParanoiaInputStream::Read(void *ptr, size_t length, Error &error)
 {
-	CdioParanoiaInputStream *cis = (CdioParanoiaInputStream *)is;
 	size_t nbytes = 0;
 	int diff;
 	size_t len, maxwrite;
@@ -319,20 +320,20 @@ input_cdio_read(InputStream *is, void *ptr, size_t length,
 
 
 		/* end of track ? */
-		if (cis->lsn_from + cis->lsn_relofs > cis->lsn_to)
+		if (lsn_from + lsn_relofs > lsn_to)
 			break;
 
 		//current sector was changed ?
-		if (cis->lsn_relofs != cis->buffer_lsn) {
-			rbuf = cdio_paranoia_read(cis->para, nullptr);
+		if (lsn_relofs != buffer_lsn) {
+			rbuf = cdio_paranoia_read(para, nullptr);
 
-			s_err = cdda_errors(cis->drv);
+			s_err = cdda_errors(drv);
 			if (s_err) {
 				FormatError(cdio_domain,
 					    "paranoia_read: %s", s_err);
 				free(s_err);
 			}
-			s_mess = cdda_messages(cis->drv);
+			s_mess = cdda_messages(drv);
 			if (s_mess) {
 				free(s_mess);
 			}
@@ -342,15 +343,15 @@ input_cdio_read(InputStream *is, void *ptr, size_t length,
 				return 0;
 			}
 			//store current buffer
-			memcpy(cis->buffer, rbuf, CDIO_CD_FRAMESIZE_RAW);
-			cis->buffer_lsn = cis->lsn_relofs;
+			memcpy(buffer, rbuf, CDIO_CD_FRAMESIZE_RAW);
+			buffer_lsn = lsn_relofs;
 		} else {
 			//use cached sector
-			rbuf = (int16_t*) cis->buffer;
+			rbuf = (int16_t *)buffer;
 		}
 
 		//correct offset
-		diff = cis->offset - cis->lsn_relofs * CDIO_CD_FRAMESIZE_RAW;
+		diff = offset - lsn_relofs * CDIO_CD_FRAMESIZE_RAW;
 
 		assert(diff >= 0 && diff < CDIO_CD_FRAMESIZE_RAW);
 
@@ -364,8 +365,8 @@ input_cdio_read(InputStream *is, void *ptr, size_t length,
 		nbytes += len;
 
 		//update offset
-		cis->offset += len;
-		cis->lsn_relofs = cis->offset / CDIO_CD_FRAMESIZE_RAW;
+		offset += len;
+		lsn_relofs = offset / CDIO_CD_FRAMESIZE_RAW;
 		//update length
 		length -= len;
 	}
@@ -373,12 +374,10 @@ input_cdio_read(InputStream *is, void *ptr, size_t length,
 	return nbytes;
 }
 
-static bool
-input_cdio_eof(InputStream *is)
+bool
+CdioParanoiaInputStream::IsEOF()
 {
-	CdioParanoiaInputStream *cis = (CdioParanoiaInputStream *)is;
-
-	return (cis->lsn_from + cis->lsn_relofs > cis->lsn_to);
+	return lsn_from + lsn_relofs > lsn_to;
 }
 
 const InputPlugin input_plugin_cdio_paranoia = {
@@ -386,11 +385,4 @@ const InputPlugin input_plugin_cdio_paranoia = {
 	input_cdio_init,
 	nullptr,
 	input_cdio_open,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	input_cdio_read,
-	input_cdio_eof,
-	input_cdio_seek,
 };
diff --git a/src/input/plugins/CurlInputPlugin.cxx b/src/input/plugins/CurlInputPlugin.cxx
index fa93a1d7e..bb7ddcfdb 100644
--- a/src/input/plugins/CurlInputPlugin.cxx
+++ b/src/input/plugins/CurlInputPlugin.cxx
@@ -120,23 +120,6 @@ struct CurlInputStream final : public InputStream {
 	static InputStream *Open(const char *url, Mutex &mutex, Cond &cond,
 				 Error &error);
 
-	bool Check(Error &error);
-
-	bool IsEOF() const {
-		return easy == nullptr && buffer.IsEmpty();
-	}
-
-	bool Seek(InputPlugin::offset_type offset, int whence, Error &error);
-
-	Tag *ReadTag();
-
-	bool IsAvailable() const {
-		return postponed_error.IsDefined() || easy == nullptr ||
-			!buffer.IsEmpty();
-	}
-
-	size_t Read(void *ptr, size_t size, Error &error);
-
 	bool InitEasy(Error &error);
 
 	/**
@@ -180,6 +163,23 @@ struct CurlInputStream final : public InputStream {
 	 * Runs in the I/O thread.  The caller must not hold locks.
 	 */
 	void RequestDone(CURLcode result, long status);
+
+	/* virtual methods from InputStream */
+	bool Check(Error &error) override;
+
+	bool IsEOF() override {
+		return easy == nullptr && buffer.IsEmpty();
+	}
+
+	Tag *ReadTag() override;
+
+	bool IsAvailable() override {
+		return postponed_error.IsDefined() || easy == nullptr ||
+			!buffer.IsEmpty();
+	}
+
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
 };
 
 class CurlMulti;
@@ -660,14 +660,7 @@ CurlInputStream::Check(Error &error)
 	return success;
 }
 
-static bool
-input_curl_check(InputStream *is, Error &error)
-{
-	CurlInputStream &c = *(CurlInputStream *)is;
-	return c.Check(error);
-}
-
-inline Tag *
+Tag *
 CurlInputStream::ReadTag()
 {
 	Tag *result = tag;
@@ -675,13 +668,6 @@ CurlInputStream::ReadTag()
 	return result;
 }
 
-static Tag *
-input_curl_tag(InputStream *is)
-{
-	CurlInputStream &c = *(CurlInputStream *)is;
-	return c.ReadTag();
-}
-
 inline bool
 CurlInputStream::FillBuffer(Error &error)
 {
@@ -758,14 +744,7 @@ CurlInputStream::CopyIcyTag()
 	tag = new_tag;
 }
 
-static bool
-input_curl_available(InputStream *is)
-{
-	const CurlInputStream &c = *(const CurlInputStream *)is;
-	return c.IsAvailable();
-}
-
-inline size_t
+size_t
 CurlInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	size_t nbytes;
@@ -797,21 +776,6 @@ CurlInputStream::Read(void *ptr, size_t read_size, Error &error)
 	return nbytes;
 }
 
-static size_t
-input_curl_read(InputStream *is, void *ptr, size_t size,
-		Error &error)
-{
-	CurlInputStream &c = *(CurlInputStream *)is;
-	return c.Read(ptr, size, error);
-}
-
-static bool
-input_curl_eof(gcc_unused InputStream *is)
-{
-	const CurlInputStream &c = *(const CurlInputStream *)is;
-	return c.IsEOF();
-}
-
 inline void
 CurlInputStream::HeaderReceived(const char *name, std::string &&value)
 {
@@ -1091,15 +1055,6 @@ CurlInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
 	return true;
 }
 
-static bool
-input_curl_seek(InputStream *is, InputPlugin::offset_type offset,
-		int whence,
-		Error &error)
-{
-	CurlInputStream &c = *(CurlInputStream *)is;
-	return c.Seek(offset, whence, error);
-}
-
 inline InputStream *
 CurlInputStream::Open(const char *url, Mutex &mutex, Cond &cond,
 		      Error &error)
@@ -1136,11 +1091,4 @@ const struct InputPlugin input_plugin_curl = {
 	input_curl_init,
 	input_curl_finish,
 	input_curl_open,
-	input_curl_check,
-	nullptr,
-	input_curl_tag,
-	input_curl_available,
-	input_curl_read,
-	input_curl_eof,
-	input_curl_seek,
 };
diff --git a/src/input/plugins/DespotifyInputPlugin.cxx b/src/input/plugins/DespotifyInputPlugin.cxx
index 86fbbbad3..faceb6057 100644
--- a/src/input/plugins/DespotifyInputPlugin.cxx
+++ b/src/input/plugins/DespotifyInputPlugin.cxx
@@ -66,13 +66,15 @@ public:
 	static InputStream *Open(const char *url, Mutex &mutex, Cond &cond,
 				 Error &error);
 
-	bool IsEOF() const {
+	void Callback(int sig);
+
+	/* virtual methods from InputStream */
+
+	bool IsEOF() override {
 		return eof;
 	}
 
-	size_t Read(void *ptr, size_t size, Error &error);
-
-	Tag *ReadTag() {
+	Tag *ReadTag() override {
 		if (tag.IsEmpty())
 			return nullptr;
 
@@ -81,7 +83,7 @@ public:
 		return result;
 	}
 
-	void Callback(int sig);
+	size_t Read(void *ptr, size_t size, Error &error) override;
 
 private:
 	void FillBuffer();
@@ -201,7 +203,7 @@ input_despotify_open(const char *url, Mutex &mutex, Cond &cond, Error &error)
 	return DespotifyInputStream::Open(url, mutex, cond, error);
 }
 
-inline size_t
+size_t
 DespotifyInputStream::Read(void *ptr, size_t read_size,
 			   gcc_unused Error &error)
 {
@@ -217,39 +219,9 @@ DespotifyInputStream::Read(void *ptr, size_t read_size,
 	return to_cpy;
 }
 
-static size_t
-input_despotify_read(InputStream *is, void *ptr, size_t size, Error &error)
-{
-	DespotifyInputStream *ctx = (DespotifyInputStream *)is;
-	return ctx->Read(ptr, size, error);
-}
-
-static bool
-input_despotify_eof(InputStream *is)
-{
-	DespotifyInputStream *ctx = (DespotifyInputStream *)is;
-
-	return ctx->IsEOF();
-}
-
-static Tag *
-input_despotify_tag(InputStream *is)
-{
-	DespotifyInputStream *ctx = (DespotifyInputStream *)is;
-
-	return ctx->ReadTag();
-}
-
 const InputPlugin input_plugin_despotify = {
 	"despotify",
 	nullptr,
 	nullptr,
 	input_despotify_open,
-	nullptr,
-	nullptr,
-	input_despotify_tag,
-	nullptr,
-	input_despotify_read,
-	input_despotify_eof,
-	nullptr,
 };
diff --git a/src/input/plugins/FfmpegInputPlugin.cxx b/src/input/plugins/FfmpegInputPlugin.cxx
index 366a99f46..de79a09ed 100644
--- a/src/input/plugins/FfmpegInputPlugin.cxx
+++ b/src/input/plugins/FfmpegInputPlugin.cxx
@@ -56,6 +56,11 @@ struct FfmpegInputStream final : public InputStream {
 	~FfmpegInputStream() {
 		avio_close(h);
 	}
+
+	/* virtual methods from InputStream */
+	bool IsEOF() override;
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
 };
 
 static constexpr Domain ffmpeg_domain("ffmpeg");
@@ -106,43 +111,35 @@ input_ffmpeg_open(const char *uri,
 	return new FfmpegInputStream(uri, mutex, cond, h);
 }
 
-static size_t
-input_ffmpeg_read(InputStream *is, void *ptr, size_t size,
-		  Error &error)
+size_t
+FfmpegInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
-	FfmpegInputStream *i = (FfmpegInputStream *)is;
-
-	int ret = avio_read(i->h, (unsigned char *)ptr, size);
+	int ret = avio_read(h, (unsigned char *)ptr, read_size);
 	if (ret <= 0) {
 		if (ret < 0)
 			error.Set(ffmpeg_domain, "avio_read() failed");
 
-		i->eof = true;
+		eof = true;
 		return false;
 	}
 
-	is->offset += ret;
+	offset += ret;
 	return (size_t)ret;
 }
 
-static bool
-input_ffmpeg_eof(InputStream *is)
+bool
+FfmpegInputStream::IsEOF()
 {
-	FfmpegInputStream *i = (FfmpegInputStream *)is;
-
-	return i->eof;
+	return eof;
 }
 
-static bool
-input_ffmpeg_seek(InputStream *is, InputPlugin::offset_type offset,
-		  int whence,
-		  Error &error)
+bool
+FfmpegInputStream::Seek(offset_type new_offset, int whence, Error &error)
 {
-	FfmpegInputStream *i = (FfmpegInputStream *)is;
-	int64_t ret = avio_seek(i->h, offset, whence);
+	int64_t ret = avio_seek(h, new_offset, whence);
 
 	if (ret >= 0) {
-		i->eof = false;
+		eof = false;
 		return true;
 	} else {
 		error.Set(ffmpeg_domain, "avio_seek() failed");
@@ -155,11 +152,4 @@ const InputPlugin input_plugin_ffmpeg = {
 	input_ffmpeg_init,
 	nullptr,
 	input_ffmpeg_open,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	input_ffmpeg_read,
-	input_ffmpeg_eof,
-	input_ffmpeg_seek,
 };
diff --git a/src/input/plugins/FileInputPlugin.cxx b/src/input/plugins/FileInputPlugin.cxx
index e96347c6e..7c7b4e85f 100644
--- a/src/input/plugins/FileInputPlugin.cxx
+++ b/src/input/plugins/FileInputPlugin.cxx
@@ -48,6 +48,15 @@ struct FileInputStream final : public InputStream {
 	~FileInputStream() {
 		close(fd);
 	}
+
+	/* virtual methods from InputStream */
+
+	bool IsEOF() override {
+		return GetOffset() >= GetSize();
+	}
+
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
 };
 
 static InputStream *
@@ -89,56 +98,37 @@ input_file_open(const char *filename,
 	return new FileInputStream(filename, fd, st.st_size, mutex, cond);
 }
 
-static bool
-input_file_seek(InputStream *is, InputPlugin::offset_type offset,
-		int whence,
-		Error &error)
+bool
+FileInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
+		      Error &error)
 {
-	FileInputStream *fis = (FileInputStream *)is;
-
-	offset = (InputPlugin::offset_type)lseek(fis->fd, (off_t)offset, whence);
-	if (offset < 0) {
+	new_offset = (InputPlugin::offset_type)lseek(fd, (off_t)new_offset,
+						     whence);
+	if (new_offset < 0) {
 		error.SetErrno("Failed to seek");
 		return false;
 	}
 
-	is->offset = offset;
+	offset = new_offset;
 	return true;
 }
 
-static size_t
-input_file_read(InputStream *is, void *ptr, size_t size,
-		Error &error)
+size_t
+FileInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
-	FileInputStream *fis = (FileInputStream *)is;
-	ssize_t nbytes;
-
-	nbytes = read(fis->fd, ptr, size);
+	ssize_t nbytes = read(fd, ptr, read_size);
 	if (nbytes < 0) {
 		error.SetErrno("Failed to read");
 		return 0;
 	}
 
-	is->offset += nbytes;
+	offset += nbytes;
 	return (size_t)nbytes;
 }
 
-static bool
-input_file_eof(InputStream *is)
-{
-	return is->GetOffset() >= is->GetSize();
-}
-
 const InputPlugin input_plugin_file = {
 	"file",
 	nullptr,
 	nullptr,
 	input_file_open,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	input_file_read,
-	input_file_eof,
-	input_file_seek,
 };
diff --git a/src/input/plugins/MmsInputPlugin.cxx b/src/input/plugins/MmsInputPlugin.cxx
index a5d4bc09d..b1ff6a890 100644
--- a/src/input/plugins/MmsInputPlugin.cxx
+++ b/src/input/plugins/MmsInputPlugin.cxx
@@ -40,7 +40,8 @@ public:
 
 protected:
 	virtual bool Open(gcc_unused Error &error) override;
-	virtual size_t Read(void *ptr, size_t size, Error &error) override;
+	virtual size_t ThreadRead(void *ptr, size_t size,
+				  Error &error) override;
 
 	virtual void Close() {
 		mmsx_close(mms);
@@ -89,7 +90,7 @@ input_mms_open(const char *url,
 }
 
 size_t
-MmsInputStream::Read(void *ptr, size_t read_size, Error &error)
+MmsInputStream::ThreadRead(void *ptr, size_t read_size, Error &error)
 {
 	int nbytes = mmsx_read(nullptr, mms, (char *)ptr, read_size);
 	if (nbytes <= 0) {
@@ -106,11 +107,4 @@ const InputPlugin input_plugin_mms = {
 	nullptr,
 	nullptr,
 	input_mms_open,
-	ThreadInputStream::Check,
-	nullptr,
-	nullptr,
-	ThreadInputStream::Available,
-	ThreadInputStream::Read,
-	ThreadInputStream::IsEOF,
-	nullptr,
 };
diff --git a/src/input/plugins/NfsInputPlugin.cxx b/src/input/plugins/NfsInputPlugin.cxx
index 19eda0605..d667e8f2d 100644
--- a/src/input/plugins/NfsInputPlugin.cxx
+++ b/src/input/plugins/NfsInputPlugin.cxx
@@ -54,33 +54,42 @@ public:
 		nfs_destroy_context(ctx);
 	}
 
-	bool IsEOF() const {
+	/* virtual methods from InputStream */
+
+	bool IsEOF() override {
 		return offset >= size;
 	}
 
-	size_t Read(void *ptr, size_t read_size, Error &error) {
-		int nbytes = nfs_read(ctx, fh, read_size, (char *)ptr);
-		if (nbytes < 0) {
-			error.SetErrno(-nbytes, "nfs_read() failed");
-			nbytes = 0;
-		}
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
+};
 
-		return nbytes;
+size_t
+NfsInputStream::Read(void *ptr, size_t read_size, Error &error)
+{
+	int nbytes = nfs_read(ctx, fh, read_size, (char *)ptr);
+	if (nbytes < 0) {
+		error.SetErrno(-nbytes, "nfs_read() failed");
+		nbytes = 0;
 	}
 
-	bool Seek(InputStream::offset_type new_offset, int whence, Error &error) {
-		uint64_t current_offset;
-		int result = nfs_lseek(ctx, fh, new_offset, whence,
-				       &current_offset);
-		if (result < 0) {
-			error.SetErrno(-result, "smbc_lseek() failed");
-			return false;
-		}
-
-		offset = current_offset;
-		return true;
+	return nbytes;
+}
+
+bool
+NfsInputStream::Seek(offset_type new_offset, int whence, Error &error)
+{
+	uint64_t current_offset;
+	int result = nfs_lseek(ctx, fh, new_offset, whence,
+			       &current_offset);
+	if (result < 0) {
+		error.SetErrno(-result, "smbc_lseek() failed");
+		return false;
 	}
-};
+
+	offset = current_offset;
+	return true;
+}
 
 /*
  * InputPlugin methods
@@ -148,40 +157,9 @@ input_nfs_open(const char *uri,
 	return new NfsInputStream(uri, mutex, cond, ctx, fh, st.st_size);
 }
 
-static size_t
-input_nfs_read(InputStream *is, void *ptr, size_t size,
-		     Error &error)
-{
-	NfsInputStream &s = *(NfsInputStream *)is;
-	return s.Read(ptr, size, error);
-}
-
-static bool
-input_nfs_eof(InputStream *is)
-{
-	NfsInputStream &s = *(NfsInputStream *)is;
-	return s.IsEOF();
-}
-
-static bool
-input_nfs_seek(InputStream *is,
-		     InputPlugin::offset_type offset, int whence,
-		     Error &error)
-{
-	NfsInputStream &s = *(NfsInputStream *)is;
-	return s.Seek(offset, whence, error);
-}
-
 const InputPlugin input_plugin_nfs = {
 	"nfs",
 	nullptr,
 	nullptr,
 	input_nfs_open,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	input_nfs_read,
-	input_nfs_eof,
-	input_nfs_seek,
 };
diff --git a/src/input/plugins/RewindInputPlugin.cxx b/src/input/plugins/RewindInputPlugin.cxx
index b1ec3ab62..b11fd8b80 100644
--- a/src/input/plugins/RewindInputPlugin.cxx
+++ b/src/input/plugins/RewindInputPlugin.cxx
@@ -26,7 +26,12 @@
 #include <string.h>
 #include <stdio.h>
 
-extern const InputPlugin rewind_input_plugin;
+static const InputPlugin rewind_input_plugin = {
+	nullptr,
+	nullptr,
+	nullptr,
+	nullptr,
+};
 
 class RewindInputStream final : public InputStream {
 	InputStream *input;
@@ -63,30 +68,31 @@ public:
 		delete input;
 	}
 
-	bool Check(Error &error) {
+	/* virtual methods from InputStream */
+
+	bool Check(Error &error) override {
 		return input->Check(error);
 	}
 
-	void Update() {
+	void Update() override {
 		if (!ReadingFromBuffer())
 			CopyAttributes();
 	}
 
-	Tag *ReadTag() {
-		return input->ReadTag();
+	bool IsEOF() override {
+		return !ReadingFromBuffer() && input->IsEOF();
 	}
 
-	bool IsAvailable() {
-		return input->IsAvailable();
+	Tag *ReadTag() override {
+		return input->ReadTag();
 	}
 
-	size_t Read(void *ptr, size_t size, Error &error);
-
-	bool IsEOF() {
-		return !ReadingFromBuffer() && input->IsEOF();
+	bool IsAvailable() override {
+		return input->IsAvailable();
 	}
 
-	bool Seek(InputPlugin::offset_type offset, int whence, Error &error);
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
 
 private:
 	/**
@@ -121,39 +127,7 @@ private:
 	}
 };
 
-static bool
-input_rewind_check(InputStream *is, Error &error)
-{
-	RewindInputStream *r = (RewindInputStream *)is;
-
-	return r->Check(error);
-}
-
-static void
-input_rewind_update(InputStream *is)
-{
-	RewindInputStream *r = (RewindInputStream *)is;
-
-	r->Update();
-}
-
-static Tag *
-input_rewind_tag(InputStream *is)
-{
-	RewindInputStream *r = (RewindInputStream *)is;
-
-	return r->ReadTag();
-}
-
-static bool
-input_rewind_available(InputStream *is)
-{
-	RewindInputStream *r = (RewindInputStream *)is;
-
-	return r->IsAvailable();
-}
-
-inline size_t
+size_t
 RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	if (ReadingFromBuffer()) {
@@ -193,23 +167,6 @@ RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 	}
 }
 
-static size_t
-input_rewind_read(InputStream *is, void *ptr, size_t size,
-		  Error &error)
-{
-	RewindInputStream *r = (RewindInputStream *)is;
-
-	return r->Read(ptr, size, error);
-}
-
-static bool
-input_rewind_eof(InputStream *is)
-{
-	RewindInputStream *r = (RewindInputStream *)is;
-
-	return r->IsEOF();
-}
-
 inline bool
 RewindInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
 			Error &error)
@@ -240,30 +197,6 @@ RewindInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
 	}
 }
 
-static bool
-input_rewind_seek(InputStream *is, InputPlugin::offset_type offset,
-		  int whence,
-		  Error &error)
-{
-	RewindInputStream *r = (RewindInputStream *)is;
-
-	return r->Seek(offset, whence, error);
-}
-
-const InputPlugin rewind_input_plugin = {
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	input_rewind_check,
-	input_rewind_update,
-	input_rewind_tag,
-	input_rewind_available,
-	input_rewind_read,
-	input_rewind_eof,
-	input_rewind_seek,
-};
-
 InputStream *
 input_rewind_open(InputStream *is)
 {
diff --git a/src/input/plugins/SmbclientInputPlugin.cxx b/src/input/plugins/SmbclientInputPlugin.cxx
index 07ffb83c4..01ee2616a 100644
--- a/src/input/plugins/SmbclientInputPlugin.cxx
+++ b/src/input/plugins/SmbclientInputPlugin.cxx
@@ -50,34 +50,14 @@ public:
 		smbclient_mutex.unlock();
 	}
 
-	bool IsEOF() const {
-		return offset >= size;
-	}
-
-	size_t Read(void *ptr, size_t read_size, Error &error) {
-		smbclient_mutex.lock();
-		ssize_t nbytes = smbc_read(fd, ptr, read_size);
-		smbclient_mutex.unlock();
-		if (nbytes < 0) {
-			error.SetErrno("smbc_read() failed");
-			nbytes = 0;
-		}
+	/* virtual methods from InputStream */
 
-		return nbytes;
+	bool IsEOF() override {
+		return offset >= size;
 	}
 
-	bool Seek(InputStream::offset_type new_offset, int whence, Error &error) {
-		smbclient_mutex.lock();
-		off_t result = smbc_lseek(fd, new_offset, whence);
-		smbclient_mutex.unlock();
-		if (result < 0) {
-			error.SetErrno("smbc_lseek() failed");
-			return false;
-		}
-
-		offset = result;
-		return true;
-	}
+	size_t Read(void *ptr, size_t size, Error &error) override;
+	bool Seek(offset_type offset, int whence, Error &error) override;
 };
 
 /*
@@ -141,28 +121,34 @@ input_smbclient_open(const char *uri,
 	return new SmbclientInputStream(uri, mutex, cond, ctx, fd, st);
 }
 
-static size_t
-input_smbclient_read(InputStream *is, void *ptr, size_t size,
-		     Error &error)
+size_t
+SmbclientInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
-	SmbclientInputStream &s = *(SmbclientInputStream *)is;
-	return s.Read(ptr, size, error);
-}
+	smbclient_mutex.lock();
+	ssize_t nbytes = smbc_read(fd, ptr, read_size);
+	smbclient_mutex.unlock();
+	if (nbytes < 0) {
+		error.SetErrno("smbc_read() failed");
+		nbytes = 0;
+	}
 
-static bool
-input_smbclient_eof(InputStream *is)
-{
-	SmbclientInputStream &s = *(SmbclientInputStream *)is;
-	return s.IsEOF();
+	return nbytes;
 }
 
-static bool
-input_smbclient_seek(InputStream *is,
-		     InputPlugin::offset_type offset, int whence,
-		     Error &error)
+bool
+SmbclientInputStream::Seek(InputStream::offset_type new_offset,
+			   int whence, Error &error)
 {
-	SmbclientInputStream &s = *(SmbclientInputStream *)is;
-	return s.Seek(offset, whence, error);
+	smbclient_mutex.lock();
+	off_t result = smbc_lseek(fd, new_offset, whence);
+	smbclient_mutex.unlock();
+	if (result < 0) {
+		error.SetErrno("smbc_lseek() failed");
+		return false;
+	}
+
+	offset = result;
+	return true;
 }
 
 const InputPlugin input_plugin_smbclient = {
@@ -170,11 +156,4 @@ const InputPlugin input_plugin_smbclient = {
 	input_smbclient_init,
 	nullptr,
 	input_smbclient_open,
-	nullptr,
-	nullptr,
-	nullptr,
-	nullptr,
-	input_smbclient_read,
-	input_smbclient_eof,
-	input_smbclient_seek,
 };