From 36ac02772c42c41b454cc0da051cebcddcd433e2 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Wed, 15 Sep 2021 17:15:52 +0200
Subject: ASAP::O: Stream switching

---
 src/im-asapo.c | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 118 insertions(+), 4 deletions(-)

(limited to 'src/im-asapo.c')

diff --git a/src/im-asapo.c b/src/im-asapo.c
index 5f4f2b65..0fc0a2b2 100644
--- a/src/im-asapo.c
+++ b/src/im-asapo.c
@@ -47,6 +47,7 @@
 
 struct im_asapo
 {
+	char *stream;
 	AsapoConsumerHandle consumer;
 	AsapoStringHandle group_id;
 };
@@ -114,23 +115,130 @@ struct im_asapo *im_asapo_connect(const char *endpoint,
 	asapo_consumer_set_timeout(a->consumer, 1000);
 
 	a->group_id = asapo_string_from_c_str(group_id);
+	a->stream = NULL;
 
 	return a;
 }
 
 
+static int select_last_stream(struct im_asapo *a)
+{
+	AsapoStreamInfosHandle si;
+	size_t len;
+	int i;
+	AsapoStreamInfoHandle st;
+	AsapoErrorHandle err = asapo_new_handle();
+
+	si = asapo_consumer_get_stream_list(a->consumer, NULL,
+	                                    kAllStreams, &err);
+
+	if ( asapo_is_error(err) ) {
+		show_asapo_error("Couldn't get ASAP::O stream list", err);
+		asapo_free_handle(err);
+		return 1;
+	}
+
+	STATUS("for info: stream list:\n");
+	n = asapo_stream_infos_get_size(si);
+	for ( i=0; i<n; i++ ) {
+		AsapoStreamInfoHandle st;
+		st = asapo_stream_infos_get_item(si, i);
+		STATUS("Stream %i: %s\n", i, asapo_stream_info_get_name(st));
+		asapo_free_handle(st);
+	}
+	STATUS("end of stream list\n");
+
+	st = asapo_stream_infos_get_item(si, n-1);
+	a->stream = strdup(asapo_stream_info_get_name(st));
+	asapo_free_handle(st);
+
+	asapo_free_handle(si);
+	asapo_free_handle(err);
+	return 0;
+}
+
+
+static int select_next_stream(struct im_asapo *a)
+{
+	AsapoStreamInfosHandle si;
+	size_t len;
+	int i;
+	AsapoErrorHandle err = asapo_new_handle();
+
+	si = asapo_consumer_get_stream_list(a->consumer, NULL,
+	                                    kAllStreams, &err);
+
+	if ( asapo_is_error(err) ) {
+		show_asapo_error("Couldn't get ASAP::O stream list", err);
+		asapo_free_handle(err);
+		return 1;
+	}
+
+	n = asapo_stream_infos_get_size(si);
+	for ( i=n-1; i>0; i-- ) {
+
+		AsapoStreamInfoHandle st;
+		const char *name;
+
+		st = asapo_stream_infos_get_item(si, i);
+		name = asapo_stream_info_get_name(st);
+
+		if ( strcmp(name, a->stream) == 0 ) {
+			free(a->stream);
+			a->stream = strdup(asapo_stream_info_get_next_stream(st));
+			asapo_free_handle(st);
+			break;
+		}
+
+		asapo_free_handle(st);
+	}
+	asapo_free_handle(si);
+	asapo_free_handle(err);
+
+	return 0;
+}
+
+
+static void skip_to_stream_end(struct im_asapo *a)
+{
+	/* FIXME: Implementation */
+}
+
+
 void *im_asapo_fetch(struct im_asapo *a, size_t *pdata_size)
 {
 	void *data_copy;
-	AsapoMessageMetaHandle meta = asapo_new_handle();
-	AsapoMessageDataHandle data = asapo_new_handle();
+	AsapoMessageMetaHandle meta;
+	AsapoMessageDataHandle data;
 	AsapoErrorHandle err = asapo_new_handle();
 	uint64_t msg_size;
 
+	if ( a->stream == NULL ) {
+		if ( select_last_stream(a) ) {
+			asapo_free_handle(&err);
+			return NULL;
+		}
+		skip_to_stream_end(a);
+	}
+
+	meta = asapo_new_handle();
+	data = asapo_new_handle();
+
 	asapo_consumer_get_next(a->consumer, a->group_id, &meta, &data,
-	                        "default", &err);
+	                        a->stream, &err);
+	if ( asapo_error_get_type(err) == kEndOfStream ) {
+		select_next_stream(a);
+		asapo_free_handle(&err);
+		asapo_free_handle(&meta);
+		asapo_free_handle(&data);
+		return NULL;  /* Please call back later! */
+	}
+
 	if ( asapo_is_error(err) ) {
 		show_asapo_error("Couldn't get next ASAP::O record", err);
+		asapo_free_handle(&err);
+		asapo_free_handle(&meta);
+		asapo_free_handle(&data);
 		return NULL;
 	}
 
@@ -141,7 +249,13 @@ void *im_asapo_fetch(struct im_asapo *a, size_t *pdata_size)
 	STATUS("ASAP::O size: %lli\n", (long long int)msg_size);
 
 	data_copy = malloc(msg_size);
-	if ( data_copy == NULL ) return NULL;
+	if ( data_copy == NULL ) {
+		ERROR("Failed to copy data block.\n");
+		asapo_free_handle(&err);
+		asapo_free_handle(&meta);
+		asapo_free_handle(&data);
+		return NULL;
+	}
 	memcpy(data_copy, asapo_message_data_get_as_chars(data), msg_size);
 
 	asapo_free_handle(&err);
-- 
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