Clean-up: ust-consumer: replace manual metadata cache buffer allocation

[lttng-tools.git] / src / common / consumer / consumer-metadata-cache.h

diff --git a/src/common/consumer/consumer-metadata-cache.h b/src/common/consumer/consumer-metadata-cache.h
index ecb7e15495d2a1706fa013c0d9b9741af90aa328..b207cc79c233df23fb926aec7382b83094700a0d 100644 (file)
--- a/src/common/consumer/consumer-metadata-cache.h
+++ b/src/common/consumer/consumer-metadata-cache.h
@@ -10,22 +10,37 @@
 #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).
@@ -35,13 +50,13 @@ 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,
                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,
                uint64_t offset, int timer);
-int consumer_metadata_wakeup_pipe(const struct lttng_consumer_channel *channel);
 
 #endif /* CONSUMER_METADATA_CACHE_H */