X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=include%2Fbabeltrace%2Fiterator.h;h=5c3939c32b4261eaae4ed3676a20fbb205586c73;hb=f3985ab106d89d8e764c1a8dd0c8bda09b755d10;hp=07f8f2ffeff1d8e90389478cd33a320cfb999eda;hpb=50cb52a8fd57684ccdc316f609f5d51f4dfcc2eb;p=babeltrace.git

diff --git a/include/babeltrace/iterator.h b/include/babeltrace/iterator.h
index 07f8f2ff..5c3939c3 100644
--- a/include/babeltrace/iterator.h
+++ b/include/babeltrace/iterator.h
@@ -15,49 +15,72 @@
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
  */
 
 #include <babeltrace/format.h>
 #include <babeltrace/context.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Flags for the iterator read_event */
+enum {
+	BT_ITER_FLAG_LOST_EVENTS	= (1 << 0),
+	BT_ITER_FLAG_RETRY		= (1 << 1),
+};
+
 /* Forward declarations */
 struct bt_iter;
 struct bt_saved_pos;
 
-struct bt_iter_pos {
-	enum {
-		BT_SEEK_TIME,		/* uses u.seek_time */
-		BT_SEEK_RESTORE,	/* uses u.restore */
-		BT_SEEK_CUR,
-		BT_SEEK_BEGIN,
-		BT_SEEK_END,
-	} type;
-	union {
-		uint64_t seek_time;
-		struct bt_saved_pos *restore;
-	} u;
-};
+/*
+ * bt_iter is an abstract class, each format has to implement its own
+ * iterator derived from this parent class.
+ */
 
 /*
- * bt_iter_create - Allocate a trace collection iterator.
+ * bt_iter_pos
  *
- * begin_pos and end_pos are optional parameters to specify the position
- * at which the trace collection should be seeked upon iterator
- * creation, and the position at which iteration will start returning
- * "EOF".
+ * This structure represents the position where to set an iterator.
  *
- * By default, if begin_pos is NULL, a BT_SEEK_CUR is performed at
- * creation. By default, if end_pos is NULL, a BT_SEEK_END (end of
- * trace) is the EOF criterion.
+ * type represents the type of seek to use.
+ * u is the argument of the seek if necessary :
+ * - seek_time is the real timestamp to seek to when using BT_SEEK_TIME, it
+ *   is expressed in nanoseconds
+ * - restore is a position saved with bt_iter_get_pos, it is used with
+ *   BT_SEEK_RESTORE.
+ *
+ * Note about BT_SEEK_LAST: if many events happen to be at the last
+ * timestamp, it is implementation-defined which event will be the last,
+ * and the order of events with the same timestamp may not be the same
+ * as normal iteration on the trace. Therefore, it is recommended to
+ * only use BT_SEEK_LAST to get the timestamp of the last event(s) in
+ * the trace.
  */
-struct bt_iter *bt_iter_create(struct bt_context *ctx,
-		struct bt_iter_pos *begin_pos,
-		struct bt_iter_pos *end_pos);
+enum bt_iter_pos_type {
+	BT_SEEK_TIME,		/* uses u.seek_time */
+	BT_SEEK_RESTORE,	/* uses u.restore */
+	BT_SEEK_CUR,
+	BT_SEEK_BEGIN,
+	BT_SEEK_LAST,
+};
 
-/*
- * bt_iter_destroy - Free a trace collection iterator.
- */
-void bt_iter_destroy(struct bt_iter *iter);
+struct bt_iter_pos {
+	enum bt_iter_pos_type type;
+	union {
+		uint64_t seek_time;
+		struct bt_saved_pos *restore;
+	} u;
+};
 
 /*
  * bt_iter_next: Move trace collection position to the next event.
@@ -72,8 +95,7 @@ int bt_iter_next(struct bt_iter *iter);
  * The position returned by this function needs to be freed by
  * bt_iter_free_pos after use.
  */
-struct bt_iter_pos *
-	bt_iter_get_pos(struct bt_iter *iter);
+struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter);
 
 /*
  * bt_iter_free_pos - Free the position.
@@ -99,9 +121,13 @@ int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *pos);
  *
  * This function allocates and returns a new bt_iter_pos (which must be freed
  * with bt_iter_free_pos) to be able to restore an iterator position based on a
- * timestamp.
+ * real timestamp.
  */
 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 		uint64_t timestamp);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* _BABELTRACE_ITERATOR_H */