X-Git-Url: http://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fconsumer%2Fconsumer-metadata-cache.h;h=b207cc79c233df23fb926aec7382b83094700a0d;hp=7dcf6976f3ada26eb4adf05beba86e710bc28752;hb=9eac98281fd4923ea52b94abffd0cf8cfa27588e;hpb=93ec662e687dc15a3601704a1e0c96c51ad228c9

diff --git a/src/common/consumer/consumer-metadata-cache.h b/src/common/consumer/consumer-metadata-cache.h
index 7dcf6976f..b207cc79c 100644
--- a/src/common/consumer/consumer-metadata-cache.h
+++ b/src/common/consumer/consumer-metadata-cache.h
@@ -1,41 +1,46 @@
 /*
- * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
- *                      David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #ifndef CONSUMER_METADATA_CACHE_H
 #define CONSUMER_METADATA_CACHE_H
 
 #include <common/consumer/consumer.h>
+#include <common/dynamic-buffer.h>
 
-struct consumer_metadata_cache {
-	char *data;
-	uint64_t cache_alloc_size;
+enum consumer_metadata_cache_write_status {
+	CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR = -1,
+	/*
+	 * New metadata content was appended to the cache successfully.
+	 * Previously available content remains valid.
+	 */
+	CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT = 0,
+	/*
+	 * The new content pushed to the cache invalidated the content that
+	 * was already present. The contents of the cache should be re-read.
+	 */
+	CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED,
 	/*
-	 * Current version of the metadata cache.
+	 * A metadata cache write can simply overwrite an already existing
+	 * section of the cache (and it should be a write-through with identical
+	 * data). From the caller's standpoint, there is no change to the state
+	 * of the cache.
 	 */
+	CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE,
+};
+
+struct consumer_metadata_cache {
+	/* Current version of the metadata cache. */
 	uint64_t version;
 	/*
-	 * The upper-limit of data written inside the buffer.
-	 *
-	 * With the total_bytes_written it allows us to keep track of when the
-	 * cache contains contiguous metadata ready to be sent to the RB.
+	 * Size is the upper-limit of data written inside the buffer.
 	 * All cached data is contiguous.
 	 */
-	uint64_t max_offset;
+	struct lttng_dynamic_buffer contents;
 	/*
 	 * Lock to update the metadata cache and push into the ring_buffer
 	 * (ustctl_write_metadata_to_channel).
@@ -45,9 +50,10 @@ struct consumer_metadata_cache {
 	pthread_mutex_t lock;
 };
 
-int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
+enum consumer_metadata_cache_write_status
+consumer_metadata_cache_write(struct consumer_metadata_cache *cache,
 		unsigned int offset, unsigned int len, uint64_t version,
-		char *data);
+		const char *data);
 int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel);
 void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel);
 int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,