[lttng-dev] [UST PATCH 1/2] Specialize lttng_ust_lib_ring_buffer_client_cb

[Julien Desfossez]

Prepare the ring-buffer config to have custom callbacks. These custom
callbacks are not related to the ring-buffer operations but allow
applications to add custom functions.
No additional feature or change in behaviour in this patch.

Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
---
 include/lttng/ringbuffer-config.h                |    1 +
 include/lttng/ust-events.h                       |    6 +++---
 liblttng-ust/lttng-rb-clients.h                  |    8 ++++++++
 liblttng-ust/lttng-ring-buffer-client.h          |   18 +++++++++++++++++-
 liblttng-ust/lttng-ring-buffer-metadata-client.h |   18 +++++++++++++++++-
 5 files changed, 46 insertions(+), 5 deletions(-)
 create mode 100644 liblttng-ust/lttng-rb-clients.h

diff --git a/include/lttng/ringbuffer-config.h b/include/lttng/ringbuffer-config.h
index 3b7d348..e81b827 100644
--- a/include/lttng/ringbuffer-config.h
+++ b/include/lttng/ringbuffer-config.h
@@ -204,6 +204,7 @@ struct lttng_ust_lib_ring_buffer_config {
 	 * callbacks and update the cb pointers.
 	 */
 	int client_type;
+	const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr;
 	char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
 };
 
diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
index f40c044..153c0ff 100644
--- a/include/lttng/ust-events.h
+++ b/include/lttng/ust-events.h
@@ -569,9 +569,9 @@ int lttng_add_ip_to_ctx(struct lttng_ctx **ctx);
 void lttng_context_vtid_reset(void);
 void lttng_context_vpid_reset(void);
 
-extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_metadata;
-extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_discard;
-extern const struct lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_overwrite;
+extern const struct specialized_lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_metadata;
+extern const struct specialized_lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_discard;
+extern const struct specialized_lttng_ust_lib_ring_buffer_client_cb *lttng_client_callbacks_overwrite;
 
 struct lttng_transport *lttng_transport_find(const char *name);
 
diff --git a/liblttng-ust/lttng-rb-clients.h b/liblttng-ust/lttng-rb-clients.h
new file mode 100644
index 0000000..37fd842
--- /dev/null
+++ b/liblttng-ust/lttng-rb-clients.h
@@ -0,0 +1,8 @@
+#ifndef _LTTNG_RB_CLIENT_H
+#define _LTTNG_RB_CLIENT_H
+
+struct specialized_lttng_ust_lib_ring_buffer_client_cb {
+	struct lttng_ust_lib_ring_buffer_client_cb parent;
+};
+
+#endif /* _LTTNG_RB_CLIENT_H */
diff --git a/liblttng-ust/lttng-ring-buffer-client.h b/liblttng-ust/lttng-ring-buffer-client.h
index 72b6d2c..94db97e 100644
--- a/liblttng-ust/lttng-ring-buffer-client.h
+++ b/liblttng-ust/lttng-ring-buffer-client.h
@@ -161,6 +161,7 @@ unsigned char record_header_size(const struct lttng_ust_lib_ring_buffer_config *
 }
 
 #include "../libringbuffer/api.h"
+#include "lttng-rb-clients.h"
 
 static
 void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config *config,
@@ -385,6 +386,19 @@ static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *
 {
 }
 
+static const
+struct specialized_lttng_ust_lib_ring_buffer_client_cb client_cb = {
+	.parent = {
+		.ring_buffer_clock_read = client_ring_buffer_clock_read,
+		.record_header_size = client_record_header_size,
+		.subbuffer_header_size = client_packet_header_size,
+		.buffer_begin = client_buffer_begin,
+		.buffer_end = client_buffer_end,
+		.buffer_create = client_buffer_create,
+		.buffer_finalize = client_buffer_finalize,
+	},
+};
+
 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 	.cb.record_header_size = client_record_header_size,
@@ -404,9 +418,11 @@ static const struct lttng_ust_lib_ring_buffer_config client_config = {
 	.ipi = RING_BUFFER_NO_IPI_BARRIER,
 	.wakeup = LTTNG_CLIENT_WAKEUP,
 	.client_type = LTTNG_CLIENT_TYPE,
+
+	.cb_ptr = &client_cb.parent,
 };
 
-const struct lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_config.cb;
+const struct specialized_lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 
 static
 struct lttng_channel *_channel_create(const char *name,
diff --git a/liblttng-ust/lttng-ring-buffer-metadata-client.h b/liblttng-ust/lttng-ring-buffer-metadata-client.h
index 89f2620..5098f21 100644
--- a/liblttng-ust/lttng-ring-buffer-metadata-client.h
+++ b/liblttng-ust/lttng-ring-buffer-metadata-client.h
@@ -61,6 +61,7 @@ unsigned char record_header_size(const struct lttng_ust_lib_ring_buffer_config *
 }
 
 #include "../libringbuffer/api.h"
+#include "lttng-rb-clients.h"
 
 static uint64_t client_ring_buffer_clock_read(struct channel *chan)
 {
@@ -153,6 +154,19 @@ static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf,
 {
 }
 
+static const
+struct specialized_lttng_ust_lib_ring_buffer_client_cb client_cb = {
+	.parent = {
+		.ring_buffer_clock_read = client_ring_buffer_clock_read,
+		.record_header_size = client_record_header_size,
+		.subbuffer_header_size = client_packet_header_size,
+		.buffer_begin = client_buffer_begin,
+		.buffer_end = client_buffer_end,
+		.buffer_create = client_buffer_create,
+		.buffer_finalize = client_buffer_finalize,
+	},
+};
+
 static const struct lttng_ust_lib_ring_buffer_config client_config = {
 	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 	.cb.record_header_size = client_record_header_size,
@@ -172,9 +186,11 @@ static const struct lttng_ust_lib_ring_buffer_config client_config = {
 	.ipi = RING_BUFFER_NO_IPI_BARRIER,
 	.wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
 	.client_type = LTTNG_CLIENT_TYPE,
+
+	 .cb_ptr = &client_cb.parent,
 };
 
-const struct lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_config.cb;
+const struct specialized_lttng_ust_lib_ring_buffer_client_cb *LTTNG_CLIENT_CALLBACKS = &client_cb;
 
 static
 struct lttng_channel *_channel_create(const char *name,
-- 
1.7.10.4