avro.patch

diff --git a/lang/c/src/avro/io.h b/lang/c/src/avro/io.h
index ffbb68dc5..5bb2ee699 100644
--- a/lang/c/src/avro/io.h
+++ b/lang/c/src/avro/io.h
@@ -109,12 +109,17 @@ int avro_file_writer_create_with_codec(const char *path,
 int avro_file_writer_create_with_codec_fp(FILE *fp, const char *path, int should_close,
 				avro_schema_t schema, avro_file_writer_t * writer,
 				const char *codec, size_t block_size);
+int avro_file_writer_create_with_codec_metadata_fp(FILE *fp, const char *path, int should_close,
+				avro_schema_t schema, avro_file_writer_t * writer,
+				const char *codec, size_t block_size, avro_value_t *meta);
 int avro_file_writer_open(const char *path, avro_file_writer_t * writer);
 int avro_file_writer_open_bs(const char *path, avro_file_writer_t * writer, size_t block_size);
 int avro_file_reader(const char *path, avro_file_reader_t * reader);
 int avro_file_reader_fp(FILE *fp, const char *path, int should_close,
 			avro_file_reader_t * reader);
 
+int avro_file_reader_json_schema(const char *file_path, const char **json_schema);
+
 avro_schema_t
 avro_file_reader_get_writer_schema(avro_file_reader_t reader);
 
diff --git a/lang/c/src/datafile.c b/lang/c/src/datafile.c
index c9d4dfeb6..a2c9d54b1 100644
--- a/lang/c/src/datafile.c
+++ b/lang/c/src/datafile.c
@@ -73,7 +73,7 @@ static int write_sync(avro_file_writer_t w)
 	return avro_write(w->writer, w->sync, sizeof(w->sync));
 }
 
-static int write_header(avro_file_writer_t w)
+static int write_header(avro_file_writer_t w, avro_value_t *extra_meta)
 {
 	int rval;
 	uint8_t version = 1;
@@ -82,6 +82,15 @@ static int write_header(avro_file_writer_t w)
 	const avro_encoding_t *enc = &avro_binary_encoding;
 	int64_t schema_len;
 
+	const char *json_schema = NULL;
+	size_t json_schema_len = 0;
+	if (extra_meta != NULL)
+	{
+		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 */
 	generate_sync(w);
 
@@ -94,15 +103,24 @@ static int write_header(avro_file_writer_t w)
 	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));
+
 	check(rval, enc->write_long(w->writer, 0));
 	return write_sync(w);
 }
@@ -140,7 +158,7 @@ file_writer_init_fp(FILE *fp, const char *path, int should_close, const char *mo
 #endif
 
 static int
-file_writer_create(FILE *fp, const char *path, int should_close, avro_schema_t schema, avro_file_writer_t w, size_t block_size)
+file_writer_create(FILE *fp, const char *path, int should_close, avro_schema_t schema, avro_file_writer_t w, size_t block_size, avro_value_t *extra_meta)
 {
 	int rval;
 
@@ -169,7 +187,7 @@ file_writer_create(FILE *fp, const char *path, int should_close, avro_schema_t s
 	}
 
 	w->writers_schema = avro_schema_incref(schema);
-	return write_header(w);
+	return write_header(w, extra_meta);
 }
 
 int
@@ -196,6 +214,15 @@ int avro_file_writer_create_with_codec(const char *path,
 int avro_file_writer_create_with_codec_fp(FILE *fp, const char *path, int should_close,
 			avro_schema_t schema, avro_file_writer_t * writer,
 			const char *codec, size_t block_size)
+{
+	return avro_file_writer_create_with_codec_metadata_fp(fp, path, should_close, schema, writer, codec,
+														  block_size, NULL);
+}
+
+
+int avro_file_writer_create_with_codec_metadata_fp(FILE *fp, const char *path, int should_close,
+			avro_schema_t schema, avro_file_writer_t * writer,
+			const char *codec, size_t block_size, avro_value_t *extra_meta)
 {
 	avro_file_writer_t w;
 	int rval;
@@ -226,7 +253,7 @@ int avro_file_writer_create_with_codec_fp(FILE *fp, const char *path, int should
 		avro_freet(struct avro_file_writer_t_, w);
 		return rval;
 	}
-	rval = file_writer_create(fp, path, should_close, schema, w, block_size);
+	rval = file_writer_create(fp, path, should_close, schema, w, block_size, extra_meta);
 	if (rval) {
 		avro_codec_reset(w->codec);
 		avro_freet(struct avro_codec_t_, w->codec);
@@ -541,6 +568,93 @@ int avro_file_reader_fp(FILE *fp, const char *path, int should_close,
 	return 0;
 }
 
+int
+avro_file_reader_json_schema(const char *file_path, const char **json_schema)
+{
+	FILE *file = fopen(file_path, "rb");
+	if (!file) {
+		avro_set_error("Error opening file: %s",
+			       strerror(errno));
+		return errno;
+	}
+
+	avro_reader_t reader = avro_reader_file(file);
+
+	int rval;
+
+	char		magic[4] = {0};
+
+	/* read magic footer */
+	check(rval, avro_read(reader, magic, sizeof(magic)));
+
+	if (magic[0] != 'O' || magic[1] != 'b' || magic[2] != 'j'
+		|| magic[3] != 1)
+	{
+		avro_reader_free(reader);
+		avro_set_error("Incorrect Avro container file magic number");
+		return 1;
+	}
+
+	/* each value is bytes */
+	avro_schema_t meta_values_schema = avro_schema_bytes();
+
+	/* metadata is map */
+	avro_schema_t meta_schema = avro_schema_map(meta_values_schema);
+
+	/* prepare avro interface for the schema */
+	avro_value_iface_t *meta_iface = avro_generic_class_from_schema(meta_schema);
+
+	if (meta_iface == NULL)
+	{
+		avro_reader_free(reader);
+		avro_set_error("Cannot create metadata interface");
+		return 1;
+	}
+
+	/* read avro metadata */
+	avro_value_t meta;
+
+	if (avro_generic_value_new(meta_iface, &meta) != 0)
+	{
+		avro_reader_free(reader);
+		avro_set_error("Cannot create metadata value");
+		return 1;
+	}
+
+	if (avro_value_read(reader, &meta) != 0)
+	{
+		avro_reader_free(reader);
+		avro_set_error("Cannot read file header");
+		return 1;
+	}
+
+	/* read "avro.schema" from the metadata */
+	avro_value_t schema_bytes;
+
+	if (avro_value_get_by_name(&meta, "avro.schema", &schema_bytes, NULL) != 0)
+	{
+		avro_reader_free(reader);
+		avro_set_error("File header doesn't contain a schema");
+		return 1;
+	}
+
+	const void *p = NULL;
+	size_t		len = 0;
+
+	avro_value_get_bytes(&schema_bytes, &p, &len);
+
+	char *schema = avro_malloc(len + 1);
+
+	memcpy((void *) schema, p, len);
+	schema[len] = '\0';
+
+	*json_schema = schema;
+
+	avro_reader_free(reader);
+
+	return 0;
+}
+
 int avro_file_reader(const char *path, avro_file_reader_t * reader)
 {
 	FILE *fp;
diff --git a/lang/c/src/schema.c b/lang/c/src/schema.c
index a4d8e9f89..cddea00cc 100644
--- a/lang/c/src/schema.c
+++ b/lang/c/src/schema.c
@@ -56,7 +56,7 @@ static int is_avro_id(const char *name)
 		}
 		for (i = 0; i < len; i++) {
 			if (!(isalpha(name[i])
-			      || name[i] == '_' || (i && isdigit(name[i])))) {
+			      || name[i] == '_' || name[i] == '.' || (i && isdigit(name[i])))) {
 				return 0;
 			}
 		}