Big live update, see details

[lttngtop.git] / lib / babeltrace / iterator.h

diff --git a/lib/babeltrace/iterator.h b/lib/babeltrace/iterator.h
new file mode 100644 (file)
index 0000000..50232a9
--- /dev/null
+++ b/lib/babeltrace/iterator.h
@@ -0,0 +1,132 @@
+#ifndef _BABELTRACE_ITERATOR_H
+#define _BABELTRACE_ITERATOR_H
+
+/*
+ * BabelTrace API Iterators
+ *
+ * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * 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),
+};
+
+/* Forward declarations */
+struct bt_iter;
+struct bt_saved_pos;
+
+/*
+ * bt_iter is an abstract class, each format has to implement its own
+ * iterator derived from this parent class.
+ */
+
+/*
+ * bt_iter_pos
+ *
+ * This structure represents the position where to set an iterator.
+ *
+ * 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.
+ */
+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,
+};
+
+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.
+ *
+ * Returns 0 on success, a negative value on error
+ */
+int bt_iter_next(struct bt_iter *iter);
+
+/*
+ * bt_iter_get_pos - Get the current iterator position.
+ *
+ * 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);
+
+/*
+ * bt_iter_free_pos - Free the position.
+ */
+void bt_iter_free_pos(struct bt_iter_pos *pos);
+
+/*
+ * bt_iter_set_pos: move the iterator to a given position.
+ *
+ * On error, the stream_heap is reinitialized and returned empty.
+ *
+ * Return 0 for success.
+ *
+ * Return EOF if the position requested is after the last event of the
+ * trace collection.
+ * Return -EINVAL when called with invalid parameter.
+ * Return -ENOMEM if the stream_heap could not be properly initialized.
+ */
+int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *pos);
+
+/*
+ * bt_iter_create_time_pos: create a position based on time
+ *
+ * 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
+ * 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 */