pass extrametadata as record instead of keys and values

lang/c/src/datafile.c

@@ -81,12 +81,14 @@ static int write_header(avro_file_writer_t w, avro_value_t *extra_meta)
 	avro_writer_t schema_writer;
 	const avro_encoding_t *enc = &avro_binary_encoding;
 	int64_t schema_len;
-	size_t extra_meta_index;
-	size_t extra_meta_size = 0;
 
+	const char *json_schema = NULL;
+	size_t json_schema_len = 0;
 	if (extra_meta != NULL)
 	{
-		check(rval, avro_value_get_size(extra_meta, &extra_meta_size));
+		avro_value_t meta_schema = {0};
+		check(rval, avro_value_get_by_name(extra_meta, "avroschema", &meta_schema, NULL));
+		check(rval, avro_value_get_string(&meta_schema, &json_schema, &json_schema_len));
 	}
 
 	/* Generate random sync */
@@ -95,34 +97,30 @@ static int write_header(avro_file_writer_t w, avro_value_t *extra_meta)
 	check(rval, avro_write(w->writer, "Obj", 3));
 	check(rval, avro_write(w->writer, &version, 1));
 
-	check(rval, enc->write_long(w->writer, 2 + extra_meta_size));
+	check(rval, enc->write_long(w->writer, 2));
 	check(rval, enc->write_string(w->writer, "avro.codec"));
 	check(rval, enc->write_bytes(w->writer, w->codec->name, strlen(w->codec->name)));
 	check(rval, enc->write_string(w->writer, "avro.schema"));
 	schema_writer =
 	    avro_writer_memory(&w->schema_buf[0], sizeof(w->schema_buf));
-	rval = avro_schema_to_json(w->writers_schema, schema_writer);
+
+	if (json_schema) {
+		rval = avro_write(schema_writer, (char *)json_schema, strlen(json_schema));
+	}
+	else {
+		rval = avro_schema_to_json(w->writers_schema, schema_writer);
+	}
+
 	if (rval) {
 		avro_writer_free(schema_writer);
 		return rval;
 	}
+
 	schema_len = avro_writer_tell(schema_writer);
 	avro_writer_free(schema_writer);
 	check(rval,
 	      enc->write_bytes(w->writer, w->schema_buf, schema_len));
 
-	for (extra_meta_index = 0; extra_meta_index < extra_meta_size; extra_meta_index++) {
-		avro_value_t child;
-		const char *key;
-		const void *value;
-		size_t value_len;
-
-		check(rval, avro_value_get_by_index(extra_meta, extra_meta_index, &child, &key));
-		check(rval, avro_value_get_bytes(&child, &value, &value_len));
-		check(rval, enc->write_string(w->writer, key));
-		check(rval, enc->write_bytes(w->writer, value, value_len));
-	}
-
 	check(rval, enc->write_long(w->writer, 0));
 	return write_sync(w);
 }