Basic seek support

For now just mimic the previous behaviour of babeltrace but with a basic
seek structure.
We define the babeltrace_iter_seek that seeks each file_stream of an
iterator to a given position and the babeltrace_filestream_seek function
that does the actual seek on the file_stream and can be used internally.

Signed-off-by: Julien Desfossez <julien.desfossez@polymtl.ca>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/converter/babeltrace-lib.c b/converter/babeltrace-lib.c
index d078a690474e29a24c6fc5e252a80526f71dbd4a..86fadc4a6ea23f5a91d580070c30acb55ec36d76 100644 (file)
--- a/converter/babeltrace-lib.c
+++ b/converter/babeltrace-lib.c
@@ -156,7 +156,79 @@ int stream_compare(void *a, void *b)
                return 0;
 }
 
-/* TODO: use begin_pos/end_pos */
+/*
+ * babeltrace_filestream_seek: seek a filestream to given position.
+ *
+ * The stream_id parameter is only useful for BT_SEEK_RESTORE.
+ */
+static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
+               const struct trace_collection_pos *begin_pos,
+               unsigned long stream_id)
+{
+       int ret = 0;
+
+       switch (begin_pos->type) {
+       case BT_SEEK_CUR:
+               /*
+                * just insert into the heap we should already know
+                * the timestamps
+                */
+               break;
+       case BT_SEEK_BEGIN:
+               ctf_move_pos_slow(&file_stream->pos, 0, SEEK_SET);
+               ret = stream_read_event(file_stream);
+               break;
+       case BT_SEEK_TIME:
+       case BT_SEEK_RESTORE:
+       case BT_SEEK_END:
+       default:
+               assert(0); /* Not yet defined */
+       }
+
+       return ret;
+}
+
+/*
+ * babeltrace_iter_seek: seek iterator to given position.
+ */
+int babeltrace_iter_seek(struct babeltrace_iter *iter,
+               const struct trace_collection_pos *begin_pos)
+{
+    int i, stream_id;
+       int ret = 0;
+       struct trace_collection *tc = iter->tc;
+
+       for (i = 0; i < tc->array->len; i++) {
+               struct ctf_trace *tin;
+               struct trace_descriptor *td_read;
+
+               td_read = g_ptr_array_index(tc->array, i);
+               tin = container_of(td_read, struct ctf_trace, parent);
+
+               /* Populate heap with each stream */
+               for (stream_id = 0; stream_id < tin->streams->len;
+                               stream_id++) {
+                       struct ctf_stream_class *stream;
+                       int filenr;
+
+                       stream = g_ptr_array_index(tin->streams, stream_id);
+                       for (filenr = 0; filenr < stream->streams->len;
+                                       filenr++) {
+                               struct ctf_file_stream *file_stream;
+
+                               file_stream = g_ptr_array_index(stream->streams,
+                                               filenr);
+                               ret = babeltrace_filestream_seek(file_stream, begin_pos,
+                                               stream_id);
+                               if (ret < 0)
+                                       goto end;
+                       }
+               }
+       }
+end:
+       return ret;
+}
+
 struct babeltrace_iter *babeltrace_iter_create(struct trace_collection *tc,
                struct trace_collection_pos *begin_pos,
                struct trace_collection_pos *end_pos)
@@ -170,6 +242,7 @@ struct babeltrace_iter *babeltrace_iter_create(struct trace_collection *tc,
                goto error_malloc;
        iter->stream_heap = g_new(struct ptr_heap, 1);
        iter->tc = tc;
+       iter->end_pos = end_pos;
 
        ret = heap_init(iter->stream_heap, 0, stream_compare);
        if (ret < 0)
@@ -198,12 +271,15 @@ struct babeltrace_iter *babeltrace_iter_create(struct trace_collection *tc,
                                file_stream = g_ptr_array_index(stream->streams,
                                                filenr);
 
-                               ret = stream_read_event(file_stream);
-                               if (ret == EOF) {
-                                       ret = 0;
-                                       continue;
-                               } else if (ret) {
-                                       goto error;
+                               if (begin_pos) {
+                                   ret = babeltrace_filestream_seek(file_stream, begin_pos,
+                                                       stream_id);
+                                   if (ret == EOF) {
+                                          ret = 0;
+                                          continue;
+                                   } else if (ret) {
+                                          goto error;
+                                   }
                                }
                                /* Add to heap */
                                ret = heap_insert(iter->stream_heap, file_stream);
@@ -286,12 +362,14 @@ int convert_trace(struct trace_descriptor *td_write,
        struct ctf_stream *stream;
        struct ctf_stream_event *event;
        struct ctf_text_stream_pos *sout;
+       struct trace_collection_pos begin_pos;
        int ret = 0;
 
        sout = container_of(td_write, struct ctf_text_stream_pos,
                        trace_descriptor);
 
-       iter = babeltrace_iter_create(trace_collection_read, NULL, NULL);
+       begin_pos.type = BT_SEEK_BEGIN;
+       iter = babeltrace_iter_create(trace_collection_read, &begin_pos, NULL);
        while (babeltrace_iter_read_event(iter, &stream, &event) == 0) {
                ret = sout->parent.event_cb(&sout->parent, stream);
                if (ret) {