4 files changed, 99 insertions, 4 deletions

diff --git a/src/encoder/flac_encoder.c b/src/encoder/flac_encoder.c
index 9f60bdae5..e32588e29 100644
--- a/src/encoder/flac_encoder.c
+++ b/src/encoder/flac_encoder.c
@@ -354,6 +354,7 @@ const struct encoder_plugin flac_encoder_plugin = {
 	.finish = flac_encoder_finish,
 	.open = flac_encoder_open,
 	.close = flac_encoder_close,
+	.end = flac_encoder_flush,
 	.flush = flac_encoder_flush,
 	.write = flac_encoder_write,
 	.read = flac_encoder_read,
diff --git a/src/encoder/twolame_encoder.c b/src/encoder/twolame_encoder.c
index 00ebcc0d7..934b2ab24 100644
--- a/src/encoder/twolame_encoder.c
+++ b/src/encoder/twolame_encoder.c
@@ -300,6 +300,7 @@ const struct encoder_plugin twolame_encoder_plugin = {
 	.finish = twolame_encoder_finish,
 	.open = twolame_encoder_open,
 	.close = twolame_encoder_close,
+	.end = twolame_encoder_flush,
 	.flush = twolame_encoder_flush,
 	.write = twolame_encoder_write,
 	.read = twolame_encoder_read,
diff --git a/src/encoder/vorbis_encoder.c b/src/encoder/vorbis_encoder.c
index 3e9d486b6..fcf2b5135 100644
--- a/src/encoder/vorbis_encoder.c
+++ b/src/encoder/vorbis_encoder.c
@@ -285,8 +285,6 @@ vorbis_encoder_pre_tag(struct encoder *_encoder, G_GNUC_UNUSED GError **error)
 	vorbis_analysis_init(&encoder->vd, &encoder->vi);
 	vorbis_block_init(&encoder->vd, &encoder->vb);
 
-	ogg_stream_reset(&encoder->os);
-
 	encoder->flush = true;
 	return true;
 }
@@ -407,6 +405,7 @@ const struct encoder_plugin vorbis_encoder_plugin = {
 	.finish = vorbis_encoder_finish,
 	.open = vorbis_encoder_open,
 	.close = vorbis_encoder_close,
+	.end = vorbis_encoder_pre_tag,
 	.flush = vorbis_encoder_flush,
 	.pre_tag = vorbis_encoder_pre_tag,
 	.tag = vorbis_encoder_tag,
diff --git a/src/encoder_plugin.h b/src/encoder_plugin.h
index 95b3da016..33a379115 100644
--- a/src/encoder_plugin.h
+++ b/src/encoder_plugin.h
@@ -22,6 +22,7 @@
 
 #include <glib.h>
 
+#include <assert.h>
 #include <stdbool.h>
 #include <stddef.h>
 
@@ -32,6 +33,10 @@ struct tag;
 
 struct encoder {
 	const struct encoder_plugin *plugin;
+
+#ifndef NDEBUG
+	bool open, pre_tag, tag, end;
+#endif
 };
 
 struct encoder_plugin {
@@ -48,6 +53,8 @@ struct encoder_plugin {
 
 	void (*close)(struct encoder *encoder);
 
+	bool (*end)(struct encoder *encoder, GError **error);
+
 	bool (*flush)(struct encoder *encoder, GError **error);
 
 	bool (*pre_tag)(struct encoder *encoder, GError **error);
@@ -73,6 +80,10 @@ encoder_struct_init(struct encoder *encoder,
 		    const struct encoder_plugin *plugin)
 {
 	encoder->plugin = plugin;
+
+#ifndef NDEBUG
+	encoder->open = false;
+#endif
 }
 
 /**
@@ -98,6 +109,8 @@ encoder_init(const struct encoder_plugin *plugin,
 static inline void
 encoder_finish(struct encoder *encoder)
 {
+	assert(!encoder->open);
+
 	encoder->plugin->finish(encoder);
 }
 
@@ -116,7 +129,14 @@ static inline bool
 encoder_open(struct encoder *encoder, struct audio_format *audio_format,
 	     GError **error)
 {
-	return encoder->plugin->open(encoder, audio_format, error);
+	assert(!encoder->open);
+
+	bool success = encoder->plugin->open(encoder, audio_format, error);
+#ifndef NDEBUG
+	encoder->open = success;
+	encoder->pre_tag = encoder->tag = encoder->end = false;
+#endif
+	return success;
 }
 
 /**
@@ -128,8 +148,43 @@ encoder_open(struct encoder *encoder, struct audio_format *audio_format,
 static inline void
 encoder_close(struct encoder *encoder)
 {
+	assert(encoder->open);
+
 	if (encoder->plugin->close != NULL)
 		encoder->plugin->close(encoder);
+
+#ifndef NDEBUG
+	encoder->open = false;
+#endif
+}
+
+/**
+ * Ends the stream: flushes the encoder object, generate an
+ * end-of-stream marker (if applicable), make everything which might
+ * currently be buffered available by encoder_read().
+ *
+ * After this function has been called, the encoder may not be usable
+ * for more data, and only encoder_read() and encoder_close() can be
+ * called.
+ *
+ * @param encoder the encoder
+ * @param error location to store the error occuring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_end(struct encoder *encoder, GError **error)
+{
+	assert(encoder->open);
+	assert(!encoder->end);
+
+#ifndef NDEBUG
+	encoder->end = true;
+#endif
+
+	/* this method is optional */
+	return encoder->plugin->end != NULL
+		? encoder->plugin->end(encoder, error)
+		: true;
 }
 
 /**
@@ -143,6 +198,11 @@ encoder_close(struct encoder *encoder)
 static inline bool
 encoder_flush(struct encoder *encoder, GError **error)
 {
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(!encoder->tag);
+	assert(!encoder->end);
+
 	/* this method is optional */
 	return encoder->plugin->flush != NULL
 		? encoder->plugin->flush(encoder, error)
@@ -162,10 +222,20 @@ encoder_flush(struct encoder *encoder, GError **error)
 static inline bool
 encoder_pre_tag(struct encoder *encoder, GError **error)
 {
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(!encoder->tag);
+	assert(!encoder->end);
+
 	/* this method is optional */
-	return encoder->plugin->pre_tag != NULL
+	bool success = encoder->plugin->pre_tag != NULL
 		? encoder->plugin->pre_tag(encoder, error)
 		: true;
+
+#ifndef NDEBUG
+	encoder->pre_tag = success;
+#endif
+	return success;
 }
 
 /**
@@ -182,6 +252,15 @@ encoder_pre_tag(struct encoder *encoder, GError **error)
 static inline bool
 encoder_tag(struct encoder *encoder, const struct tag *tag, GError **error)
 {
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(encoder->tag);
+	assert(!encoder->end);
+
+#ifndef NDEBUG
+	encoder->tag = false;
+#endif
+
 	/* this method is optional */
 	return encoder->plugin->tag != NULL
 		? encoder->plugin->tag(encoder, tag, error)
@@ -201,6 +280,11 @@ static inline bool
 encoder_write(struct encoder *encoder, const void *data, size_t length,
 	      GError **error)
 {
+	assert(encoder->open);
+	assert(!encoder->pre_tag);
+	assert(!encoder->tag);
+	assert(!encoder->end);
+
 	return encoder->plugin->write(encoder, data, length, error);
 }
 
@@ -215,6 +299,16 @@ encoder_write(struct encoder *encoder, const void *data, size_t length,
 static inline size_t
 encoder_read(struct encoder *encoder, void *dest, size_t length)
 {
+	assert(encoder->open);
+	assert(!encoder->pre_tag || !encoder->tag);
+
+#ifndef NDEBUG
+	if (encoder->pre_tag) {
+		encoder->pre_tag = false;
+		encoder->tag = true;
+	}
+#endif
+
 	return encoder->plugin->read(encoder, dest, length);
 }