encoder_plugin: add method pre_tag()

In the "vorbis" plugin, this is a copy of the old flush() method,
while flush() gets a lot of code remove, it just sets the "flush" flag
and nothing else.  It doesn't start a new stream now, which should fix
a few problems in some players.

4 files changed, 37 insertions, 2 deletions

diff --git a/src/encoder/vorbis_encoder.c b/src/encoder/vorbis_encoder.c
index 08147be1c..38a998bd2 100644
--- a/src/encoder/vorbis_encoder.c
+++ b/src/encoder/vorbis_encoder.c
@@ -266,6 +266,15 @@ vorbis_encoder_flush(struct encoder *_encoder, G_GNUC_UNUSED GError **error)
 {
 	struct vorbis_encoder *encoder = (struct vorbis_encoder *)_encoder;
 
+	encoder->flush = true;
+	return true;
+}
+
+static bool
+vorbis_encoder_pre_tag(struct encoder *_encoder, G_GNUC_UNUSED GError **error)
+{
+	struct vorbis_encoder *encoder = (struct vorbis_encoder *)_encoder;
+
 	vorbis_analysis_wrote(&encoder->vd, 0);
 	vorbis_encoder_blockout(encoder);
 
@@ -366,6 +375,7 @@ vorbis_encoder_read(struct encoder *_encoder, void *_dest, size_t length)
 	if (ret == 0 && encoder->flush) {
 		encoder->flush = false;
 		ret = ogg_stream_flush(&encoder->os, &page);
+
 	}
 
 	if (ret == 0)
@@ -398,6 +408,7 @@ const struct encoder_plugin vorbis_encoder_plugin = {
 	.open = vorbis_encoder_open,
 	.close = vorbis_encoder_close,
 	.flush = vorbis_encoder_flush,
+	.pre_tag = vorbis_encoder_pre_tag,
 	.tag = vorbis_encoder_tag,
 	.write = vorbis_encoder_write,
 	.read = vorbis_encoder_read,
diff --git a/src/encoder_plugin.h b/src/encoder_plugin.h
index 13fb231f4..fb00413e6 100644
--- a/src/encoder_plugin.h
+++ b/src/encoder_plugin.h
@@ -50,6 +50,8 @@ struct encoder_plugin {
 
 	bool (*flush)(struct encoder *encoder, GError **error);
 
+	bool (*pre_tag)(struct encoder *encoder, GError **error);
+
 	bool (*tag)(struct encoder *encoder, const struct tag *tag,
 		    GError **error);
 
@@ -148,8 +150,30 @@ encoder_flush(struct encoder *encoder, GError **error)
 }
 
 /**
+ * Prepare for sending a tag to the encoder.  This is used by some
+ * encoders to flush the previous sub-stream, in preparation to begin
+ * a new one.
+ *
+ * @param encoder the encoder
+ * @param tag the tag object
+ * @param error location to store the error occuring, or NULL to ignore errors.
+ * @return true on success
+ */
+static inline bool
+encoder_pre_tag(struct encoder *encoder, GError **error)
+{
+	/* this method is optional */
+	return encoder->plugin->pre_tag != NULL
+		? encoder->plugin->pre_tag(encoder, error)
+		: true;
+}
+
+/**
  * Sends a tag to the encoder.
  *
+ * Instructions: call encoder_pre_tag(); then obtain flushed data with
+ * encoder_read(); finally call encoder_tag().
+ *
  * @param encoder the encoder
  * @param tag the tag object
  * @param error location to store the error occuring, or NULL to ignore errors.
diff --git a/src/output/httpd_output_plugin.c b/src/output/httpd_output_plugin.c
index 0137965a6..40ad05c3d 100644
--- a/src/output/httpd_output_plugin.c
+++ b/src/output/httpd_output_plugin.c
@@ -523,7 +523,7 @@ httpd_output_tag(void *data, const struct tag *tag)
 
 		/* flush the current stream, and end it */
 
-		encoder_flush(httpd->encoder, NULL);
+		encoder_pre_tag(httpd->encoder, NULL);
 		httpd_output_encoder_to_clients(httpd);
 
 		/* send the tag to the encoder - which starts a new
diff --git a/src/output/shout_plugin.c b/src/output/shout_plugin.c
index 5e1ef762a..35efd9fc7 100644
--- a/src/output/shout_plugin.c
+++ b/src/output/shout_plugin.c
@@ -511,7 +511,7 @@ static void my_shout_set_tag(void *data,
 	if (sd->encoder->plugin->tag != NULL) {
 		/* encoder plugin supports stream tags */
 
-		ret = encoder_flush(sd->encoder, &error);
+		ret = encoder_pre_tag(sd->encoder, &error);
 		if (!ret) {
 			g_warning("%s", error->message);
 			g_error_free(error);