input/plugins: make InputStream the base class

Prepare for adding virtual methods.

10 files changed, 178 insertions, 224 deletions

diff --git a/src/input/plugins/AlsaInputPlugin.cxx b/src/input/plugins/AlsaInputPlugin.cxx
index 129219c01..c1ff41d55 100644
--- a/src/input/plugins/AlsaInputPlugin.cxx
+++ b/src/input/plugins/AlsaInputPlugin.cxx
@@ -32,7 +32,7 @@
 #include "util/Error.hxx"
 #include "util/StringUtil.hxx"
 #include "util/ReusableArray.hxx"
-#include "util/Cast.hxx"
+
 #include "Log.hxx"
 #include "event/MultiSocketMonitor.hxx"
 #include "event/DeferredMonitor.hxx"
@@ -64,8 +64,9 @@ static constexpr unsigned int default_rate = 44100; // cd quality
  */
 static constexpr size_t read_buffer_size = 4096;
 
-class AlsaInputStream final : MultiSocketMonitor, DeferredMonitor {
-	InputStream base;
+class AlsaInputStream final
+	: public InputStream,
+	  MultiSocketMonitor, DeferredMonitor {
 	snd_pcm_t *capture_handle;
 	size_t frame_size;
 	int frames_to_read;
@@ -81,23 +82,23 @@ class AlsaInputStream final : MultiSocketMonitor, DeferredMonitor {
 
 public:
 	AlsaInputStream(EventLoop &loop,
-			const char *uri, Mutex &mutex, Cond &cond,
+			const char *_uri, Mutex &_mutex, Cond &_cond,
 			snd_pcm_t *_handle, int _frame_size)
-		:MultiSocketMonitor(loop),
+		:InputStream(input_plugin_alsa, _uri, _mutex, _cond),
+		 MultiSocketMonitor(loop),
 		 DeferredMonitor(loop),
-		 base(input_plugin_alsa, uri, mutex, cond),
 		 capture_handle(_handle),
 		 frame_size(_frame_size),
 		 eof(false)
 	{
-		assert(uri != nullptr);
+		assert(_uri != nullptr);
 		assert(_handle != nullptr);
 
 		/* this mime type forces use of the PcmDecoderPlugin.
 		   Needs to be generalised when/if that decoder is
 		   updated to support other audio formats */
-		base.SetMimeType("audio/x-mpd-cdda-pcm");
-		base.SetReady();
+		SetMimeType("audio/x-mpd-cdda-pcm");
+		InputStream::SetReady();
 
 		frames_to_read = read_buffer_size / frame_size;
 
@@ -115,19 +116,6 @@ public:
 	static InputStream *Create(const char *uri, Mutex &mutex, Cond &cond,
 				   Error &error);
 
-#if GCC_CHECK_VERSION(4,6) || defined(__clang__)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Winvalid-offsetof"
-#endif
-
-	static constexpr AlsaInputStream *Cast(InputStream *is) {
-		return ContainerCast(is, AlsaInputStream, base);
-	}
-
-#if GCC_CHECK_VERSION(4,6) || defined(__clang__)
-#pragma GCC diagnostic pop
-#endif
-
 	bool Available() {
 		if (snd_pcm_avail(capture_handle) > frames_to_read)
 			return true;
@@ -188,18 +176,17 @@ AlsaInputStream::Create(const char *uri, Mutex &mutex, Cond &cond,
 		return nullptr;
 
 	int frame_size = snd_pcm_format_width(format) / 8 * channels;
-	AlsaInputStream *stream = new AlsaInputStream(io_thread_get(),
-						      uri, mutex, cond,
-						      handle, frame_size);
-	return &stream->base;
+	return new AlsaInputStream(io_thread_get(),
+				   uri, mutex, cond,
+				   handle, frame_size);
 }
 
 inline size_t
-AlsaInputStream::Read(void *ptr, size_t size, Error &error)
+AlsaInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	assert(ptr != nullptr);
 
-	int num_frames = size / frame_size;
+	int num_frames = read_size / frame_size;
 	int ret;
 	while ((ret = snd_pcm_readi(capture_handle, ptr, num_frames)) < 0) {
 		if (Recover(ret) < 0) {
@@ -211,7 +198,7 @@ AlsaInputStream::Read(void *ptr, size_t size, Error &error)
 	}
 
 	size_t nbytes = ret * frame_size;
-	base.offset += nbytes;
+	offset += nbytes;
 	return nbytes;
 }
 
@@ -244,9 +231,9 @@ AlsaInputStream::DispatchSockets()
 {
 	waiting = false;
 
-	const ScopeLock protect(base.mutex);
+	const ScopeLock protect(mutex);
 	/* wake up the thread that is waiting for more data */
-	base.cond.broadcast();
+	cond.broadcast();
 }
 
 inline int
@@ -389,28 +376,28 @@ alsa_input_open(const char *uri, Mutex &mutex, Cond &cond, Error &error)
 static void
 alsa_input_close(InputStream *is)
 {
-	AlsaInputStream *ais = AlsaInputStream::Cast(is);
+	AlsaInputStream *ais = (AlsaInputStream *)is;
 	delete ais;
 }
 
 static bool
 alsa_input_available(InputStream *is)
 {
-	AlsaInputStream *ais = AlsaInputStream::Cast(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::Cast(is);
+	AlsaInputStream *ais = (AlsaInputStream *)is;
 	return ais->Read(ptr, size, error);
 }
 
 static bool
 alsa_input_eof(gcc_unused InputStream *is)
 {
-	AlsaInputStream *ais = AlsaInputStream::Cast(is);
+	AlsaInputStream *ais = (AlsaInputStream *)is;
 	return ais->IsEOF();
 }
 
diff --git a/src/input/plugins/CdioParanoiaInputPlugin.cxx b/src/input/plugins/CdioParanoiaInputPlugin.cxx
index 5b4ce2ec6..8e1762427 100644
--- a/src/input/plugins/CdioParanoiaInputPlugin.cxx
+++ b/src/input/plugins/CdioParanoiaInputPlugin.cxx
@@ -50,9 +50,7 @@
 
 #include <cdio/cd_types.h>
 
-struct CdioParanoiaInputStream {
-	InputStream base;
-
+struct CdioParanoiaInputStream final : public InputStream {
 	cdrom_drive_t *drv;
 	CdIo_t *cdio;
 	cdrom_paranoia_t *para;
@@ -65,9 +63,9 @@ struct CdioParanoiaInputStream {
 	char buffer[CDIO_CD_FRAMESIZE_RAW];
 	int buffer_lsn;
 
-	CdioParanoiaInputStream(const char *uri, Mutex &mutex, Cond &cond,
+	CdioParanoiaInputStream(const char *_uri, Mutex &_mutex, Cond &_cond,
 				int _trackno)
-		:base(input_plugin_cdio_paranoia, uri, mutex, cond),
+		:InputStream(input_plugin_cdio_paranoia, _uri, _mutex, _cond),
 		 drv(nullptr), cdio(nullptr), para(nullptr),
 		 trackno(_trackno)
 	{
@@ -264,16 +262,16 @@ input_cdio_open(const char *uri,
 	/* seek to beginning of the track */
 	cdio_paranoia_seek(i->para, i->lsn_from, SEEK_SET);
 
-	i->base.ready = true;
-	i->base.seekable = true;
-	i->base.size = (i->lsn_to - i->lsn_from + 1) * CDIO_CD_FRAMESIZE_RAW;
+	i->seekable = true;
+	i->size = (i->lsn_to - i->lsn_from + 1) * CDIO_CD_FRAMESIZE_RAW;
 
 	/* hack to make MPD select the "pcm" decoder plugin */
-	i->base.SetMimeType(reverse_endian
+	i->SetMimeType(reverse_endian
 			    ? "audio/x-mpd-cdda-pcm-reverse"
 			    : "audio/x-mpd-cdda-pcm");
+	i->SetReady();
 
-	return &i->base;
+	return i;
 }
 
 static bool
@@ -287,26 +285,26 @@ input_cdio_seek(InputStream *is,
 	case SEEK_SET:
 		break;
 	case SEEK_CUR:
-		offset += cis->base.offset;
+		offset += cis->offset;
 		break;
 	case SEEK_END:
-		offset += cis->base.size;
+		offset += cis->size;
 		break;
 	}
 
-	if (offset < 0 || offset > cis->base.size) {
+	if (offset < 0 || offset > cis->size) {
 		error.Format(cdio_domain, "Invalid offset to seek %ld (%ld)",
-			     (long int)offset, (long int)cis->base.size);
+			     (long int)offset, (long int)cis->size);
 		return false;
 	}
 
 	/* simple case */
-	if (offset == cis->base.offset)
+	if (offset == cis->offset)
 		return true;
 
 	/* calculate current LSN */
 	cis->lsn_relofs = offset / CDIO_CD_FRAMESIZE_RAW;
-	cis->base.offset = offset;
+	cis->offset = offset;
 
 	cdio_paranoia_seek(cis->para, cis->lsn_from + cis->lsn_relofs, SEEK_SET);
 
@@ -360,7 +358,7 @@ input_cdio_read(InputStream *is, void *ptr, size_t length,
 		}
 
 		//correct offset
-		diff = cis->base.offset - cis->lsn_relofs * CDIO_CD_FRAMESIZE_RAW;
+		diff = cis->offset - cis->lsn_relofs * CDIO_CD_FRAMESIZE_RAW;
 
 		assert(diff >= 0 && diff < CDIO_CD_FRAMESIZE_RAW);
 
@@ -374,8 +372,8 @@ input_cdio_read(InputStream *is, void *ptr, size_t length,
 		nbytes += len;
 
 		//update offset
-		cis->base.offset += len;
-		cis->lsn_relofs = cis->base.offset / CDIO_CD_FRAMESIZE_RAW;
+		cis->offset += len;
+		cis->lsn_relofs = cis->offset / CDIO_CD_FRAMESIZE_RAW;
 		//update length
 		length -= len;
 	}
diff --git a/src/input/plugins/CurlInputPlugin.cxx b/src/input/plugins/CurlInputPlugin.cxx
index 5f8b9150a..63fb84190 100644
--- a/src/input/plugins/CurlInputPlugin.cxx
+++ b/src/input/plugins/CurlInputPlugin.cxx
@@ -67,9 +67,7 @@ static const size_t CURL_MAX_BUFFERED = 512 * 1024;
  */
 static const size_t CURL_RESUME_AT = 384 * 1024;
 
-struct CurlInputStream {
-	InputStream base;
-
+struct CurlInputStream final : public InputStream {
 	/* some buffers which were passed to libcurl, which we have
 	   too free */
 	char range[32];
@@ -106,9 +104,9 @@ struct CurlInputStream {
 
 	Error postponed_error;
 
-	CurlInputStream(const char *url, Mutex &mutex, Cond &cond,
+	CurlInputStream(const char *_url, Mutex &_mutex, Cond &_cond,
 			void *_buffer)
-		:base(input_plugin_curl, url, mutex, cond),
+		:InputStream(input_plugin_curl, _url, _mutex, _cond),
 		 request_headers(nullptr),
 		 buffer((uint8_t *)_buffer, CURL_MAX_BUFFERED),
 		 paused(false),
@@ -486,7 +484,7 @@ CurlInputStream::RequestDone(CURLcode result, long status)
 
 	FreeEasy();
 
-	const ScopeLock protect(base.mutex);
+	const ScopeLock protect(mutex);
 
 	if (result != CURLE_OK) {
 		postponed_error.Format(curl_domain, result,
@@ -497,7 +495,7 @@ CurlInputStream::RequestDone(CURLcode result, long status)
 				       status);
 	}
 
-	base.SetReady();
+	SetReady();
 }
 
 static void
@@ -688,7 +686,7 @@ inline bool
 CurlInputStream::FillBuffer(Error &error)
 {
 	while (easy != nullptr && buffer.IsEmpty())
-		base.cond.wait(base.mutex);
+		cond.wait(mutex);
 
 	if (postponed_error.IsDefined()) {
 		error = std::move(postponed_error);
@@ -768,7 +766,7 @@ input_curl_available(InputStream *is)
 }
 
 inline size_t
-CurlInputStream::Read(void *ptr, size_t size, Error &error)
+CurlInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	size_t nbytes;
 
@@ -778,22 +776,22 @@ CurlInputStream::Read(void *ptr, size_t size, Error &error)
 		if (!FillBuffer(error))
 			return 0;
 
-		nbytes = read_from_buffer(icy, buffer, ptr, size);
+		nbytes = read_from_buffer(icy, buffer, ptr, read_size);
 	} while (nbytes == 0);
 
 	if (icy.IsDefined())
 		CopyIcyTag();
 
-	base.offset += (InputPlugin::offset_type)nbytes;
+	offset += (InputPlugin::offset_type)nbytes;
 
 	if (paused && GetTotalBufferSize() < CURL_RESUME_AT) {
-		base.mutex.unlock();
+		mutex.unlock();
 
 		BlockingCall(io_thread_get(), [this](){
 				Resume();
 			});
 
-		base.mutex.lock();
+		mutex.lock();
 	}
 
 	return nbytes;
@@ -828,11 +826,11 @@ CurlInputStream::HeaderReceived(const char *name, std::string &&value)
 	if (StringEqualsCaseASCII(name, "accept-ranges")) {
 		/* a stream with icy-metadata is not seekable */
 		if (!icy.IsDefined())
-			base.seekable = true;
+			seekable = true;
 	} else if (StringEqualsCaseASCII(name, "content-length")) {
-		base.size = base.offset + ParseUint64(value.c_str());
+		size = offset + ParseUint64(value.c_str());
 	} else if (StringEqualsCaseASCII(name, "content-type")) {
-		base.SetMimeType(std::move(value));
+		SetMimeType(std::move(value));
 	} else if (StringEqualsCaseASCII(name, "icy-name") ||
 		   StringEqualsCaseASCII(name, "ice-name") ||
 		   StringEqualsCaseASCII(name, "x-audiocast-name")) {
@@ -856,7 +854,7 @@ CurlInputStream::HeaderReceived(const char *name, std::string &&value)
 
 			/* a stream with icy-metadata is not
 			   seekable */
-			base.seekable = false;
+			seekable = false;
 		}
 	}
 }
@@ -898,13 +896,13 @@ input_curl_headerfunction(void *ptr, size_t size, size_t nmemb, void *stream)
 }
 
 inline size_t
-CurlInputStream::DataReceived(const void *ptr, size_t size)
+CurlInputStream::DataReceived(const void *ptr, size_t received_size)
 {
-	assert(size > 0);
+	assert(received_size > 0);
 
-	const ScopeLock protect(base.mutex);
+	const ScopeLock protect(mutex);
 
-	if (size > buffer.GetSpace()) {
+	if (received_size > buffer.GetSpace()) {
 		paused = true;
 		return CURL_WRITEFUNC_PAUSE;
 	}
@@ -912,23 +910,23 @@ CurlInputStream::DataReceived(const void *ptr, size_t size)
 	auto w = buffer.Write();
 	assert(!w.IsEmpty());
 
-	size_t nbytes = std::min(w.size, size);
+	size_t nbytes = std::min(w.size, received_size);
 	memcpy(w.data, ptr, nbytes);
 	buffer.Append(nbytes);
 
-	const size_t remaining = size - nbytes;
+	const size_t remaining = received_size - nbytes;
 	if (remaining > 0) {
 		w = buffer.Write();
 		assert(!w.IsEmpty());
 		assert(w.size >= remaining);
 
 		memcpy(w.data, (const uint8_t *)ptr + nbytes, remaining);
-		buffer.Append(size);
+		buffer.Append(received_size);
 	}
 
-	base.ready = true;
-	base.cond.broadcast();
-	return size;
+	ready = true;
+	cond.broadcast();
+	return received_size;
 }
 
 /** called by curl when new data is available */
@@ -986,7 +984,7 @@ CurlInputStream::InitEasy(Error &error)
 		curl_easy_setopt(easy, CURLOPT_PROXYUSERPWD, proxy_auth_str);
 	}
 
-	CURLcode code = curl_easy_setopt(easy, CURLOPT_URL, base.GetURI());
+	CURLcode code = curl_easy_setopt(easy, CURLOPT_URL, GetURI());
 	if (code != CURLE_OK) {
 		error.Format(curl_domain, code,
 			     "curl_easy_setopt() failed: %s",
@@ -1003,16 +1001,16 @@ CurlInputStream::InitEasy(Error &error)
 }
 
 inline bool
-CurlInputStream::Seek(InputPlugin::offset_type offset, int whence,
+CurlInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
 		      Error &error)
 {
-	assert(base.ready);
+	assert(IsReady());
 
-	if (whence == SEEK_SET && offset == base.offset)
+	if (whence == SEEK_SET && new_offset == offset)
 		/* no-op */
 		return true;
 
-	if (!base.seekable)
+	if (!IsSeekable())
 		return false;
 
 	/* calculate the absolute offset */
@@ -1022,52 +1020,52 @@ CurlInputStream::Seek(InputPlugin::offset_type offset, int whence,
 		break;
 
 	case SEEK_CUR:
-		offset += base.offset;
+		new_offset += offset;
 		break;
 
 	case SEEK_END:
-		if (base.size < 0)
+		if (size < 0)
 			/* stream size is not known */
 			return false;
 
-		offset += base.size;
+		new_offset += size;
 		break;
 
 	default:
 		return false;
 	}
 
-	if (offset < 0)
+	if (new_offset < 0)
 		return false;
 
 	/* check if we can fast-forward the buffer */
 
-	while (offset > base.offset) {
+	while (new_offset > offset) {
 		auto r = buffer.Read();
 		if (r.IsEmpty())
 			break;
 
 		const size_t nbytes =
-			offset - base.offset < (InputPlugin::offset_type)r.size
-					       ? offset - base.offset
-					       : r.size;
+			new_offset - offset < (InputPlugin::offset_type)r.size
+						   ? new_offset - offset
+						   : r.size;
 
 		buffer.Consume(nbytes);
-		base.offset += nbytes;
+		offset += nbytes;
 	}
 
-	if (offset == base.offset)
+	if (new_offset == offset)
 		return true;
 
 	/* close the old connection and open a new one */
 
-	base.mutex.unlock();
+	mutex.unlock();
 
 	FreeEasyIndirect();
 	buffer.Clear();
 
-	base.offset = offset;
-	if (base.offset == base.size) {
+	offset = new_offset;
+	if (offset == size) {
 		/* seek to EOF: simulate empty result; avoid
 		   triggering a "416 Requested Range Not Satisfiable"
 		   response */
@@ -1079,18 +1077,18 @@ CurlInputStream::Seek(InputPlugin::offset_type offset, int whence,
 
 	/* send the "Range" header */
 
-	if (base.offset > 0) {
-		sprintf(range, "%lld-", (long long)base.offset);
+	if (offset > 0) {
+		sprintf(range, "%lld-", (long long)offset);
 		curl_easy_setopt(easy, CURLOPT_RANGE, range);
 	}
 
-	base.ready = false;
+	ready = false;
 
 	if (!input_curl_easy_add_indirect(this, error))
 		return false;
 
-	base.mutex.lock();
-	base.WaitReady();
+	mutex.lock();
+	WaitReady();
 
 	if (postponed_error.IsDefined()) {
 		error = std::move(postponed_error);
@@ -1127,7 +1125,7 @@ CurlInputStream::Open(const char *url, Mutex &mutex, Cond &cond,
 		return nullptr;
 	}
 
-	return &c->base;
+	return c;
 }
 
 static InputStream *
diff --git a/src/input/plugins/DespotifyInputPlugin.cxx b/src/input/plugins/DespotifyInputPlugin.cxx
index 702ebc132..16ef07f0d 100644
--- a/src/input/plugins/DespotifyInputPlugin.cxx
+++ b/src/input/plugins/DespotifyInputPlugin.cxx
@@ -36,9 +36,7 @@ extern "C" {
 
 #include <stdio.h>
 
-class DespotifyInputStream {
-	InputStream base;
-
+class DespotifyInputStream final : public InputStream {
 	struct despotify_session *session;
 	struct ds_track *track;
 	Tag tag;
@@ -46,11 +44,11 @@ class DespotifyInputStream {
 	size_t len_available;
 	bool eof;
 
-	DespotifyInputStream(const char *uri,
-			     Mutex &mutex, Cond &cond,
+	DespotifyInputStream(const char *_uri,
+			     Mutex &_mutex, Cond &_cond,
 			     despotify_session *_session,
 			     ds_track *_track)
-		:base(input_plugin_despotify, uri, mutex, cond),
+		:InputStream(input_plugin_despotify, _uri, _mutex, _cond),
 		 session(_session), track(_track),
 		 tag(mpd_despotify_tag_from_track(*track)),
 		 len_available(0), eof(false) {
@@ -58,8 +56,8 @@ class DespotifyInputStream {
 		memset(&pcm, 0, sizeof(pcm));
 
 		/* Despotify outputs pcm data */
-		base.SetMimeType("audio/x-mpd-cdda-pcm");
-		base.SetReady();
+		SetMimeType("audio/x-mpd-cdda-pcm");
+		SetReady();
 	}
 
 public:
@@ -190,7 +188,7 @@ DespotifyInputStream::Open(const char *url,
 		return nullptr;
 	}
 
-	return &ctx->base;
+	return ctx;
 }
 
 static InputStream *
@@ -200,16 +198,17 @@ input_despotify_open(const char *url, Mutex &mutex, Cond &cond, Error &error)
 }
 
 inline size_t
-DespotifyInputStream::Read(void *ptr, size_t size, gcc_unused Error &error)
+DespotifyInputStream::Read(void *ptr, size_t read_size,
+			   gcc_unused Error &error)
 {
 	if (len_available == 0)
 		FillBuffer();
 
-	size_t to_cpy = std::min(size, len_available);
+	size_t to_cpy = std::min(read_size, len_available);
 	memcpy(ptr, pcm.buf, to_cpy);
 	len_available -= to_cpy;
 
-	base.offset += to_cpy;
+	offset += to_cpy;
 
 	return to_cpy;
 }
diff --git a/src/input/plugins/FfmpegInputPlugin.cxx b/src/input/plugins/FfmpegInputPlugin.cxx
index d06d4705a..affd76718 100644
--- a/src/input/plugins/FfmpegInputPlugin.cxx
+++ b/src/input/plugins/FfmpegInputPlugin.cxx
@@ -33,26 +33,24 @@ extern "C" {
 #include <libavformat/avformat.h>
 }
 
-struct FfmpegInputStream {
-	InputStream base;
-
+struct FfmpegInputStream final : public InputStream {
 	AVIOContext *h;
 
 	bool eof;
 
-	FfmpegInputStream(const char *uri, Mutex &mutex, Cond &cond,
+	FfmpegInputStream(const char *_uri, Mutex &_mutex, Cond &_cond,
 			  AVIOContext *_h)
-		:base(input_plugin_ffmpeg, uri, mutex, cond),
+		:InputStream(input_plugin_ffmpeg, _uri, _mutex, _cond),
 		 h(_h), eof(false) {
-		base.ready = true;
-		base.seekable = (h->seekable & AVIO_SEEKABLE_NORMAL) != 0;
-		base.size = avio_size(h);
+		seekable = (h->seekable & AVIO_SEEKABLE_NORMAL) != 0;
+		size = avio_size(h);
 
 		/* hack to make MPD select the "ffmpeg" decoder plugin
 		   - since avio.h doesn't tell us the MIME type of the
 		   resource, we can't select a decoder plugin, but the
 		   "ffmpeg" plugin is quite good at auto-detection */
-		base.SetMimeType("audio/x-mpd-ffmpeg");
+		SetMimeType("audio/x-mpd-ffmpeg");
+		SetReady();
 	}
 
 	~FfmpegInputStream() {
@@ -105,8 +103,7 @@ input_ffmpeg_open(const char *uri,
 		return nullptr;
 	}
 
-	auto *i = new FfmpegInputStream(uri, mutex, cond, h);
-	return &i->base;
+	return new FfmpegInputStream(uri, mutex, cond, h);
 }
 
 static size_t
diff --git a/src/input/plugins/FileInputPlugin.cxx b/src/input/plugins/FileInputPlugin.cxx
index 49dc3df7e..932db2150 100644
--- a/src/input/plugins/FileInputPlugin.cxx
+++ b/src/input/plugins/FileInputPlugin.cxx
@@ -33,18 +33,16 @@
 
 static constexpr Domain file_domain("file");
 
-struct FileInputStream {
-	InputStream base;
-
+struct FileInputStream final : public InputStream {
 	int fd;
 
-	FileInputStream(const char *path, int _fd, off_t size,
-			Mutex &mutex, Cond &cond)
-		:base(input_plugin_file, path, mutex, cond),
+	FileInputStream(const char *path, int _fd, off_t _size,
+			Mutex &_mutex, Cond &_cond)
+		:InputStream(input_plugin_file, path, _mutex, _cond),
 		 fd(_fd) {
-		base.size = size;
-		base.seekable = true;
-		base.SetReady();
+		size = _size;
+		seekable = true;
+		SetReady();
 	}
 
 	~FileInputStream() {
@@ -88,9 +86,7 @@ input_file_open(const char *filename,
 	posix_fadvise(fd, (off_t)0, st.st_size, POSIX_FADV_SEQUENTIAL);
 #endif
 
-	FileInputStream *fis = new FileInputStream(filename, fd, st.st_size,
-						   mutex, cond);
-	return &fis->base;
+	return new FileInputStream(filename, fd, st.st_size, mutex, cond);
 }
 
 static bool
diff --git a/src/input/plugins/MmsInputPlugin.cxx b/src/input/plugins/MmsInputPlugin.cxx
index 845fe5d5d..d4095b2cb 100644
--- a/src/input/plugins/MmsInputPlugin.cxx
+++ b/src/input/plugins/MmsInputPlugin.cxx
@@ -33,8 +33,8 @@ class MmsInputStream final : public ThreadInputStream {
 	mmsx_t *mms;
 
 public:
-	MmsInputStream(const char *uri, Mutex &mutex, Cond &cond)
-		:ThreadInputStream(input_plugin_mms, uri, mutex, cond,
+	MmsInputStream(const char *_uri, Mutex &_mutex, Cond &_cond)
+		:ThreadInputStream(input_plugin_mms, _uri, _mutex, _cond,
 				   MMS_BUFFER_SIZE) {
 	}
 
@@ -89,9 +89,9 @@ input_mms_open(const char *url,
 }
 
 size_t
-MmsInputStream::Read(void *ptr, size_t size, Error &error)
+MmsInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
-	int nbytes = mmsx_read(nullptr, mms, (char *)ptr, size);
+	int nbytes = mmsx_read(nullptr, mms, (char *)ptr, read_size);
 	if (nbytes <= 0) {
 		if (nbytes < 0)
 			error.SetErrno("mmsx_read() failed");
diff --git a/src/input/plugins/NfsInputPlugin.cxx b/src/input/plugins/NfsInputPlugin.cxx
index 5081eff27..9b5ca5959 100644
--- a/src/input/plugins/NfsInputPlugin.cxx
+++ b/src/input/plugins/NfsInputPlugin.cxx
@@ -33,22 +33,20 @@ extern "C" {
 #include <sys/stat.h>
 #include <fcntl.h>
 
-class NfsInputStream {
-	InputStream base;
-
+class NfsInputStream final : public InputStream {
 	nfs_context *ctx;
 	nfsfh *fh;
 
 public:
-	NfsInputStream(const char *uri,
-		       Mutex &mutex, Cond &cond,
+	NfsInputStream(const char *_uri,
+		       Mutex &_mutex, Cond &_cond,
 		       nfs_context *_ctx, nfsfh *_fh,
-		       InputStream::offset_type size)
-		:base(input_plugin_nfs, uri, mutex, cond),
+		       InputStream::offset_type _size)
+		:InputStream(input_plugin_nfs, _uri, _mutex, _cond),
 		 ctx(_ctx), fh(_fh) {
-		base.ready = true;
-		base.seekable = true;
-		base.size = size;
+		seekable = true;
+		size = _size;
+		SetReady();
 	}
 
 	~NfsInputStream() {
@@ -56,16 +54,12 @@ public:
 		nfs_destroy_context(ctx);
 	}
 
-	InputStream *GetBase() {
-		return &base;
-	}
-
 	bool IsEOF() const {
-		return base.offset >= base.size;
+		return offset >= size;
 	}
 
-	size_t Read(void *ptr, size_t size, Error &error) {
-		int nbytes = nfs_read(ctx, fh, size, (char *)ptr);
+	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;
@@ -74,15 +68,16 @@ public:
 		return nbytes;
 	}
 
-	bool Seek(InputStream::offset_type offset, int whence, Error &error) {
+	bool Seek(InputStream::offset_type new_offset, int whence, Error &error) {
 		uint64_t current_offset;
-		int result = nfs_lseek(ctx, fh, offset, whence, &current_offset);
+		int result = nfs_lseek(ctx, fh, new_offset, whence,
+				       &current_offset);
 		if (result < 0) {
 			error.SetErrno(-result, "smbc_lseek() failed");
 			return false;
 		}
 
-		base.offset = current_offset;
+		offset = current_offset;
 		return true;
 	}
 };
@@ -150,8 +145,7 @@ input_nfs_open(const char *uri,
 		return nullptr;
 	}
 
-	auto is = new NfsInputStream(uri, mutex, cond, ctx, fh, st.st_size);
-	return is->GetBase();
+	return new NfsInputStream(uri, mutex, cond, ctx, fh, st.st_size);
 }
 
 static size_t
diff --git a/src/input/plugins/RewindInputPlugin.cxx b/src/input/plugins/RewindInputPlugin.cxx
index d8ef62021..9665615f8 100644
--- a/src/input/plugins/RewindInputPlugin.cxx
+++ b/src/input/plugins/RewindInputPlugin.cxx
@@ -28,9 +28,7 @@
 
 extern const InputPlugin rewind_input_plugin;
 
-class RewindInputStream {
-	InputStream base;
-
+class RewindInputStream final : public InputStream {
 	InputStream *input;
 
 	/**
@@ -56,8 +54,8 @@ class RewindInputStream {
 
 public:
 	RewindInputStream(InputStream *_input)
-		:base(rewind_input_plugin, _input->GetURI(),
-		      _input->mutex, _input->cond),
+		:InputStream(rewind_input_plugin, _input->GetURI(),
+			     _input->mutex, _input->cond),
 		 input(_input), tail(0) {
 	}
 
@@ -65,10 +63,6 @@ public:
 		input->Close();
 	}
 
-	InputStream *GetBase() {
-		return &base;
-	}
-
 	bool Check(Error &error) {
 		return input->Check(error);
 	}
@@ -100,7 +94,7 @@ private:
 	 * buffer contain more data for the next read operation?
 	 */
 	bool ReadingFromBuffer() const {
-		return tail > 0 && base.offset < input->offset;
+		return tail > 0 && offset < input->offset;
 	}
 
 	/**
@@ -110,21 +104,20 @@ private:
 	 * attributes.
 	 */
 	void CopyAttributes() {
-		InputStream *dest = &base;
 		const InputStream *src = input;
 
-		assert(dest != src);
+		assert(src != this);
 
-		if (!dest->IsReady() && src->IsReady()) {
+		if (!IsReady() && src->IsReady()) {
 			if (src->HasMimeType())
-				dest->SetMimeType(src->GetMimeType());
+				SetMimeType(src->GetMimeType());
 
-			dest->size = src->GetSize();
-			dest->seekable = src->IsSeekable();
-			dest->SetReady();
+			size = src->GetSize();
+			seekable = src->IsSeekable();
+			SetReady();
 		}
 
-		dest->offset = src->offset;
+		offset = src->offset;
 	}
 };
 
@@ -169,31 +162,31 @@ input_rewind_available(InputStream *is)
 }
 
 inline size_t
-RewindInputStream::Read(void *ptr, size_t size, Error &error)
+RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 {
 	if (ReadingFromBuffer()) {
 		/* buffered read */
 
-		assert(head == (size_t)base.offset);
+		assert(head == (size_t)offset);
 		assert(tail == (size_t)input->offset);
 
-		if (size > tail - head)
-			size = tail - head;
+		if (read_size > tail - head)
+			read_size = tail - head;
 
-		memcpy(ptr, buffer + head, size);
-		head += size;
-		base.offset += size;
+		memcpy(ptr, buffer + head, read_size);
+		head += read_size;
+		offset += read_size;
 
-		return size;
+		return read_size;
 	} else {
 		/* pass method call to underlying stream */
 
-		size_t nbytes = input->Read(ptr, size, error);
+		size_t nbytes = input->Read(ptr, read_size, error);
 
 		if (input->offset > (InputPlugin::offset_type)sizeof(buffer))
 			/* disable buffering */
 			tail = 0;
-		else if (tail == (size_t)base.offset) {
+		else if (tail == (size_t)offset) {
 			/* append to buffer */
 
 			memcpy(buffer + tail, ptr, nbytes);
@@ -226,25 +219,25 @@ input_rewind_eof(InputStream *is)
 }
 
 inline bool
-RewindInputStream::Seek(InputPlugin::offset_type offset, int whence,
+RewindInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
 			Error &error)
 {
-	assert(base.IsReady());
+	assert(IsReady());
 
 	if (whence == SEEK_SET && tail > 0 &&
-	    offset <= (InputPlugin::offset_type)tail) {
+	    new_offset <= (InputPlugin::offset_type)tail) {
 		/* buffered seek */
 
 		assert(!ReadingFromBuffer() ||
-		       head == (size_t)base.offset);
+		       head == (size_t)offset);
 		assert(tail == (size_t)input->offset);
 
-		head = (size_t)offset;
-		base.offset = offset;
+		head = (size_t)new_offset;
+		offset = new_offset;
 
 		return true;
 	} else {
-		bool success = input->Seek(offset, whence, error);
+		bool success = input->Seek(new_offset, whence, error);
 		CopyAttributes();
 
 		/* disable the buffer, because input has left the
@@ -290,6 +283,5 @@ input_rewind_open(InputStream *is)
 		/* seekable resources don't need this plugin */
 		return is;
 
-	RewindInputStream *c = new RewindInputStream(is);
-	return c->GetBase();
+	return new RewindInputStream(is);
 }
diff --git a/src/input/plugins/SmbclientInputPlugin.cxx b/src/input/plugins/SmbclientInputPlugin.cxx
index 9709d089a..c291f0608 100644
--- a/src/input/plugins/SmbclientInputPlugin.cxx
+++ b/src/input/plugins/SmbclientInputPlugin.cxx
@@ -28,21 +28,19 @@
 
 #include <libsmbclient.h>
 
-class SmbclientInputStream {
-	InputStream base;
-
+class SmbclientInputStream final : public InputStream {
 	SMBCCTX *ctx;
 	int fd;
 
 public:
-	SmbclientInputStream(const char *uri,
-			     Mutex &mutex, Cond &cond,
+	SmbclientInputStream(const char *_uri,
+			     Mutex &_mutex, Cond &_cond,
 			     SMBCCTX *_ctx, int _fd, const struct stat &st)
-		:base(input_plugin_smbclient, uri, mutex, cond),
+		:InputStream(input_plugin_smbclient, _uri, _mutex, _cond),
 		 ctx(_ctx), fd(_fd) {
-		base.ready = true;
-		base.seekable = true;
-		base.size = st.st_size;
+		seekable = true;
+		size = st.st_size;
+		SetReady();
 	}
 
 	~SmbclientInputStream() {
@@ -52,17 +50,13 @@ public:
 		smbclient_mutex.unlock();
 	}
 
-	InputStream *GetBase() {
-		return &base;
-	}
-
 	bool IsEOF() const {
-		return base.offset >= base.size;
+		return offset >= size;
 	}
 
-	size_t Read(void *ptr, size_t size, Error &error) {
+	size_t Read(void *ptr, size_t read_size, Error &error) {
 		smbclient_mutex.lock();
-		ssize_t nbytes = smbc_read(fd, ptr, size);
+		ssize_t nbytes = smbc_read(fd, ptr, read_size);
 		smbclient_mutex.unlock();
 		if (nbytes < 0) {
 			error.SetErrno("smbc_read() failed");
@@ -72,16 +66,16 @@ public:
 		return nbytes;
 	}
 
-	bool Seek(InputStream::offset_type offset, int whence, Error &error) {
+	bool Seek(InputStream::offset_type new_offset, int whence, Error &error) {
 		smbclient_mutex.lock();
-		off_t result = smbc_lseek(fd, offset, whence);
+		off_t result = smbc_lseek(fd, new_offset, whence);
 		smbclient_mutex.unlock();
 		if (result < 0) {
 			error.SetErrno("smbc_lseek() failed");
 			return false;
 		}
 
-		base.offset = result;
+		offset = result;
 		return true;
 	}
 };
@@ -144,8 +138,7 @@ input_smbclient_open(const char *uri,
 		return nullptr;
 	}
 
-	auto s = new SmbclientInputStream(uri, mutex, cond, ctx, fd, st);
-	return s->GetBase();
+	return new SmbclientInputStream(uri, mutex, cond, ctx, fd, st);
 }
 
 static size_t