API Fix: bt_ctf_iter_read_event_flags

The new bt_ctf_iter_read_event_flags function behaves like
bt_ctf_iter_read_event but takes a flag pointer.
This flag is used by the trace reading code to inform the user if some
events were discarded by the tracer in the current packet.

The new bt_ctf_get_lost_events_count function allows the user to get the
the number of events discarded immediately prior to the last event read.

[ Edit by Mathieu Desnoyers: use enum instead of define for
  BT_ITER_FLAG_LOST_EVENTS. ]

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/doc/API.txt b/doc/API.txt
index 5c06198ec1f3a721414fd221cdf089db143ff82c..bc3a4a10512e1aef477ee950de8a61d009250159 100644 (file)
--- a/doc/API.txt
+++ b/doc/API.txt
@@ -76,6 +76,14 @@ creation will return NULL. The previous iterator must be destroyed before
 creation of the new iterator. In the future, creation of multiples iterators
 will be allowed.
 
 creation of the new iterator. In the future, creation of multiples iterators
 will be allowed.
 

+The bt_ctf_iter_read_event_flags() function has the same behaviour as
+bt_ctf_iter_read_event() but takes an additionnal flag pointer. This flag is
+used to inform the user if a special condition occured while reading the event.
+As of now, only the BT_ITER_LOST_EVENTS is handled, it informs the user that
+some events were discarded by the tracer. To get the number of events lost
+immediately prior to the last event read, the user can call the
+bt_ctf_get_lost_events_count() function.
+

 Finally, we have the bt_ctf_get_iter() function which returns a struct bt_iter
 with which the iterator can be moved using one of these functions:
        bt_iter_next(),         moves the iterator to the next event
 Finally, we have the bt_ctf_get_iter() function which returns a struct bt_iter
 with which the iterator can be moved using one of these functions:
        bt_iter_next(),         moves the iterator to the next event

diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c
index f43fe91789d21d109c0adf407a0b7e951201ca39..f1fdba178f0a773d28a2286dae9eee133c29e929 100644 (file)
--- a/formats/ctf/ctf.c
+++ b/formats/ctf/ctf.c
@@ -699,6 +699,9 @@ void ctf_packet_seek(struct stream_pos *stream_pos, size_t index, int whence)
                        break;
                }
                case SEEK_SET:
                        break;
                }
                case SEEK_SET:

+                       packet_index = &g_array_index(pos->packet_cycles_index,
+                                       struct packet_index, index);
+                       pos->last_events_discarded = packet_index->events_discarded;

                        pos->cur_index = index;
                        file_stream->parent.prev_real_timestamp = 0;
                        file_stream->parent.prev_real_timestamp_end = 0;
                        pos->cur_index = index;
                        file_stream->parent.prev_real_timestamp = 0;
                        file_stream->parent.prev_real_timestamp_end = 0;

diff --git a/formats/ctf/iterator.c b/formats/ctf/iterator.c
index ec74e59029381e73acc5cbf97a7c43ae4889fedf..0ac041910f7aedf9d967600efd24e718318b6891 100644 (file)
--- a/formats/ctf/iterator.c
+++ b/formats/ctf/iterator.c
@@ -94,11 +94,13 @@ struct bt_iter *bt_ctf_get_iter(struct bt_ctf_iter *iter)
        return &iter->parent;
 }
 
        return &iter->parent;
 }
 

-struct bt_ctf_event *bt_ctf_iter_read_event(struct bt_ctf_iter *iter)
+struct bt_ctf_event *bt_ctf_iter_read_event_flags(struct bt_ctf_iter *iter,
+               int *flags)

 {
        struct ctf_file_stream *file_stream;
        struct bt_ctf_event *ret;
        struct ctf_stream_definition *stream;
 {
        struct ctf_file_stream *file_stream;
        struct bt_ctf_event *ret;
        struct ctf_stream_definition *stream;

+       struct packet_index *packet_index;

 
        /*
         * We do not want to fail for any other reason than end of
 
        /*
         * We do not want to fail for any other reason than end of


@@ -116,6 +118,24 @@ struct bt_ctf_event *bt_ctf_iter_read_event(struct bt_ctf_iter *iter)
        ret->parent = g_ptr_array_index(stream->events_by_id,
                        stream->event_id);
 
        ret->parent = g_ptr_array_index(stream->events_by_id,
                        stream->event_id);
 

+       if (flags)
+               *flags = 0;
+       if (!file_stream->pos.packet_cycles_index)
+               packet_index = NULL;
+       else
+               packet_index = &g_array_index(file_stream->pos.packet_cycles_index,
+                               struct packet_index, file_stream->pos.cur_index);
+       iter->events_lost = 0;
+       if (packet_index && packet_index->events_discarded >
+                       file_stream->pos.last_events_discarded) {
+               if (flags)
+                       *flags |= BT_ITER_FLAG_LOST_EVENTS;
+               iter->events_lost += packet_index->events_discarded -
+                       file_stream->pos.last_events_discarded;
+               file_stream->pos.last_events_discarded =
+                       packet_index->events_discarded;
+       }
+

        if (ret->parent->stream->stream_id > iter->callbacks->len)
                goto end;
 
        if (ret->parent->stream->stream_id > iter->callbacks->len)
                goto end;
 


@@ -126,3 +146,16 @@ end:
 stop:
        return NULL;
 }
 stop:
        return NULL;
 }

+
+struct bt_ctf_event *bt_ctf_iter_read_event(struct bt_ctf_iter *iter)
+{
+       return bt_ctf_iter_read_event_flags(iter, NULL);
+}
+
+uint64_t bt_ctf_get_lost_events_count(struct bt_ctf_iter *iter)
+{
+       if (!iter)
+               return -1ULL;
+
+       return iter->events_lost;
+}

diff --git a/include/babeltrace/ctf/events-internal.h b/include/babeltrace/ctf/events-internal.h
index aaa09262321dfc32f62dddb185430bc7d4e771f3..71f73539c9692c6e3d8aabd62557bec57bb0bec1 100644 (file)
--- a/include/babeltrace/ctf/events-internal.h
+++ b/include/babeltrace/ctf/events-internal.h
@@ -68,6 +68,7 @@ struct bt_ctf_iter {
         * bt_iter.
         */
        GPtrArray *dep_gc;
         * bt_iter.
         */
        GPtrArray *dep_gc;

+       uint64_t events_lost;

 };
 
 #endif /*_BABELTRACE_CTF_EVENTS_INTERNAL_H */
 };
 
 #endif /*_BABELTRACE_CTF_EVENTS_INTERNAL_H */

diff --git a/include/babeltrace/ctf/iterator.h b/include/babeltrace/ctf/iterator.h
index 9370583a58df3e6042b92f74932305234ba0bc51..449ddfeb370b1cd8baba7efce664c1046c8bb809 100644 (file)
--- a/include/babeltrace/ctf/iterator.h
+++ b/include/babeltrace/ctf/iterator.h
@@ -78,4 +78,26 @@ struct bt_ctf_event *bt_ctf_iter_read_event(struct bt_ctf_iter *iter);
 }
 #endif
 
 }
 #endif
 

+/*
+ * bt_ctf_iter_read_event_flags: Read the iterator's current event data.
+ *
+ * @iter: trace collection iterator (input). Should NOT be NULL.
+ * @flags: pointer passed by the user, in which the trace reader populates
+ * flags on special condition (BT_ITER_FLAG_*).
+ *
+ * Return current event on success, NULL on end of trace.
+ */
+struct bt_ctf_event *bt_ctf_iter_read_event_flags(struct bt_ctf_iter *iter,
+               int *flags);
+
+/*
+ * bt_ctf_get_lost_events_count: returns the number of events discarded
+ * immediately prior to the last event read
+ *
+ * @iter: trace collection iterator (input). Should NOT be NULL.
+ *
+ * Return the number of lost events or -1ULL on error.
+ */
+uint64_t bt_ctf_get_lost_events_count(struct bt_ctf_iter *iter);
+

 #endif /* _BABELTRACE_CTF_ITERATOR_H */
 #endif /* _BABELTRACE_CTF_ITERATOR_H */

diff --git a/include/babeltrace/ctf/types.h b/include/babeltrace/ctf/types.h
index 94231555c10dad3763a785b837040d08f410d52e..6a76c6bbf945c3c2e351a191cdf5b015e368f3ad 100644 (file)
--- a/include/babeltrace/ctf/types.h
+++ b/include/babeltrace/ctf/types.h
@@ -67,6 +67,7 @@ struct ctf_stream_pos {
        ssize_t offset;         /* offset from base, in bits. EOF for end of file. */
        ssize_t last_offset;    /* offset before the last read_event */
        size_t cur_index;       /* current index in packet index */
        ssize_t offset;         /* offset from base, in bits. EOF for end of file. */
        ssize_t last_offset;    /* offset before the last read_event */
        size_t cur_index;       /* current index in packet index */

+       uint64_t last_events_discarded; /* last known amount of event discarded */

        void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence); /* function called to switch packet */
 
        void (*packet_seek)(struct stream_pos *pos, size_t index,
                        int whence); /* function called to switch packet */
 

diff --git a/include/babeltrace/iterator.h b/include/babeltrace/iterator.h
index 3f7984fbe66ea00c01e6e5c95090acbf07f634fc..7eb3c5ebc4c34ffea7232afd80f8fd041fb739de 100644 (file)
--- a/include/babeltrace/iterator.h
+++ b/include/babeltrace/iterator.h
@@ -24,6 +24,11 @@
 extern "C" {
 #endif
 
 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;
 /* Forward declarations */
 struct bt_iter;
 struct bt_saved_pos;