Implement OUTPUT_META

This replaces the Decoder.add() method with Decoder.register().
The first argument is still output type, but all arguments are now
optional:

  Decoder.register(output_type,
        id='someid',
        meta=(object-type, 'Name', 'Description'))

'id' defaults to the protocol decoder instance id, and only needs changing
if a decoder chain needs to fork.
'object-type' refers to a Python object, such as int or str.

After registering, the PD submits data as usual with Decoder.put(), with
the only argument a value of the registered object-type.

1 files changed, 5 insertions, 0 deletions

diff --git a/libsigrokdecode.h.in b/libsigrokdecode.h.in
index 3beff35..a654373 100644
--- a/libsigrokdecode.h.in
+++ b/libsigrokdecode.h.in
@@ -162,6 +162,7 @@ enum {
 	SRD_OUTPUT_ANN,
 	SRD_OUTPUT_PYTHON,
 	SRD_OUTPUT_BINARY,
+	SRD_OUTPUT_META,
 };
 
 #define SRD_MAX_NUM_PROBES 64
@@ -249,6 +250,10 @@ struct srd_pd_output {
 	int output_type;
 	struct srd_decoder_inst *di;
 	char *proto_id;
+	/* Only used for OUTPUT_META. */
+	const GVariantType *meta_type;
+	char *meta_name;
+	char *meta_descr;
 };
 
 struct srd_proto_data {