X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-relayd%2Ftracefile-array.h;h=09c425fad43267f96e40b30063e28ebdf95159df;hp=9158f4fe40c3c16bd5446ea811cc44cef379b966;hb=9a9c8637bbfb1b12b8302e03d5bc0453672b4d06;hpb=a44ca2ca85e4b64729f7b88b1919fd6737dfff8a

diff --git a/src/bin/lttng-relayd/tracefile-array.h b/src/bin/lttng-relayd/tracefile-array.h
index 9158f4fe4..09c425fad 100644
--- a/src/bin/lttng-relayd/tracefile-array.h
+++ b/src/bin/lttng-relayd/tracefile-array.h
@@ -2,20 +2,10 @@
 #define _TRACEFILE_ARRAY_H
 
 /*
- * Copyright (C) 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@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.
  */
 
 #include <limits.h>
@@ -29,15 +19,30 @@ struct tracefile {
 	uint64_t seq_tail;	/* Oldest seqcount. Inclusive. */
 };
 
+enum tracefile_rotate_type {
+	TRACEFILE_ROTATE_READ,
+	TRACEFILE_ROTATE_WRITE,
+};
+
 /*
  * Represents an array of trace files in a stream.
+ * head is the most recent file/trace packet.
+ * tail is the oldest file/trace packet.
+ *
+ * There are two heads: a "read" head and a "write" head. The "write" head is
+ * the position of the newest data file. The "read" head position is only moved
+ * forward when the index is received.
+ *
+ * The viewer uses the "read" head position as upper bound, which
+ * ensures it never attempts to open a non-existing index file.
  */
 struct tracefile_array {
 	struct tracefile *tf;
 	size_t count;
 
 	/* Current head/tail files. */
-	uint64_t file_head;
+	uint64_t file_head_read;
+	uint64_t file_head_write;
 	uint64_t file_tail;
 
 	/* Overall head/tail seq for the entire array. Inclusive. */
@@ -48,10 +53,12 @@ struct tracefile_array {
 struct tracefile_array *tracefile_array_create(size_t count);
 void tracefile_array_destroy(struct tracefile_array *tfa);
 
-void tracefile_array_file_rotate(struct tracefile_array *tfa);
-void tracefile_array_commit_seq(struct tracefile_array *tfa);
+void tracefile_array_file_rotate(struct tracefile_array *tfa, enum tracefile_rotate_type type);
+void tracefile_array_commit_seq(struct tracefile_array *tfa,
+		uint64_t new_seq_head);
+void tracefile_array_reset(struct tracefile_array *tfa);
 
-uint64_t tracefile_array_get_file_index_head(struct tracefile_array *tfa);
+uint64_t tracefile_array_get_read_file_index_head(struct tracefile_array *tfa);
 /* May return -1ULL in the case where we have not received any indexes yet. */
 uint64_t tracefile_array_get_seq_head(struct tracefile_array *tfa);