ctf: introduce dry-run mode for `bt_msg_iter`

Dry-run mode can be used when component classes need to decode CTF
packets but do not want the `bt_msg_iter` to create and use the
Babeltrace library objects (bt_field, bt_message_*, etc.).

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Change-Id: I336ec4c893835e7b1d6f32262841793f7543aa06
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1417
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>

diff --git a/src/plugins/ctf/common/msg-iter/msg-iter.c b/src/plugins/ctf/common/msg-iter/msg-iter.c
index ba686961d4034d170ff1d587b5ab41fdaf91981e..5e16f64a73225fb887a2ae8e9f191512950ea6e2 100644 (file)
--- a/src/plugins/ctf/common/msg-iter/msg-iter.c
+++ b/src/plugins/ctf/common/msg-iter/msg-iter.c
@@ -133,6 +133,12 @@ struct bt_msg_iter {
        /* True to emit a stream end message. */
        bool emit_stream_end_msg;
 
+       /*
+        * True if library objects are unavailable during the decoding and
+        * should not be created/used.
+        */
+       bool dry_run;
+
        /* True to set the stream */
        bool set_stream;
 
@@ -977,7 +983,7 @@ enum bt_msg_iter_status read_packet_context_begin_state(
 
        BT_ASSERT(!notit->packet_context_field);
 
-       if (packet_context_fc->in_ir) {
+       if (packet_context_fc->in_ir && !notit->dry_run) {
                /*
                 * Create free packet context field from stream class.
                 * This field is going to be moved to the packet once we
@@ -1296,6 +1302,10 @@ enum bt_msg_iter_status after_event_header_state(
                goto end;
        }
 
+       if (G_UNLIKELY(notit->dry_run)) {
+               goto next_state;
+       }
+
        status = set_current_event_message(notit);
        if (status != BT_MSG_ITER_STATUS_OK) {
                goto end;
@@ -1304,6 +1314,8 @@ enum bt_msg_iter_status after_event_header_state(
        notit->event = bt_message_event_borrow_event(
                notit->event_msg);
        BT_ASSERT(notit->event);
+
+next_state:
        notit->state = STATE_DSCOPE_EVENT_COMMON_CONTEXT_BEGIN;
 
 end:
@@ -1323,7 +1335,7 @@ enum bt_msg_iter_status read_event_common_context_begin_state(
                goto end;
        }
 
-       if (event_common_context_fc->in_ir) {
+       if (event_common_context_fc->in_ir && !notit->dry_run) {
                BT_ASSERT(!notit->dscopes.event_common_context);
                notit->dscopes.event_common_context =
                        bt_event_borrow_common_context_field(
@@ -1376,7 +1388,7 @@ enum bt_msg_iter_status read_event_spec_context_begin_state(
                goto end;
        }
 
-       if (event_spec_context_fc->in_ir) {
+       if (event_spec_context_fc->in_ir && !notit->dry_run) {
                BT_ASSERT(!notit->dscopes.event_spec_context);
                notit->dscopes.event_spec_context =
                        bt_event_borrow_specific_context_field(
@@ -1432,7 +1444,7 @@ enum bt_msg_iter_status read_event_payload_begin_state(
                goto end;
        }
 
-       if (event_payload_fc->in_ir) {
+       if (event_payload_fc->in_ir && !notit->dry_run) {
                BT_ASSERT(!notit->dscopes.event_payload);
                notit->dscopes.event_payload =
                        bt_event_borrow_payload_field(
@@ -1958,7 +1970,7 @@ update_def_clock:
                        (uint64_t) int_fc->storing_index) = value;
        }
 
-       if (G_UNLIKELY(!fc->in_ir)) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -1995,7 +2007,7 @@ enum bt_bfcr_status bfcr_unsigned_int_char_cb(uint64_t value,
        BT_ASSERT(!int_fc->mapped_clock_class);
        BT_ASSERT(int_fc->storing_index < 0);
 
-       if (G_UNLIKELY(!fc->in_ir)) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2047,7 +2059,7 @@ enum bt_bfcr_status bfcr_signed_int_cb(int64_t value,
                        (uint64_t) int_fc->storing_index) = (uint64_t) value;
        }
 
-       if (G_UNLIKELY(!fc->in_ir)) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2078,7 +2090,7 @@ enum bt_bfcr_status bfcr_floating_point_cb(double value,
                "fc-type=%d, fc-in-ir=%d, value=%f",
                notit, notit->bfcr, fc, fc->type, fc->in_ir, value);
 
-       if (G_UNLIKELY(!fc->in_ir)) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2106,7 +2118,7 @@ enum bt_bfcr_status bfcr_string_begin_cb(
                "fc-type=%d, fc-in-ir=%d",
                notit, notit->bfcr, fc, fc->type, fc->in_ir);
 
-       if (G_UNLIKELY(!fc->in_ir)) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2143,7 +2155,7 @@ enum bt_bfcr_status bfcr_string_cb(const char *value,
                notit, notit->bfcr, fc, fc->type, fc->in_ir,
                len);
 
-       if (G_UNLIKELY(!fc->in_ir)) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2175,7 +2187,7 @@ enum bt_bfcr_status bfcr_string_end_cb(
                "fc-type=%d, fc-in-ir=%d",
                notit, notit->bfcr, fc, fc->type, fc->in_ir);
 
-       if (G_UNLIKELY(!fc->in_ir)) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2200,7 +2212,7 @@ enum bt_bfcr_status bfcr_compound_begin_cb(
                "fc-type=%d, fc-in-ir=%d",
                notit, notit->bfcr, fc, fc->type, fc->in_ir);
 
-       if (!fc->in_ir) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2250,7 +2262,7 @@ enum bt_bfcr_status bfcr_compound_end_cb(
                "fc-type=%d, fc-in-ir=%d",
                notit, notit->bfcr, fc, fc->type, fc->in_ir);
 
-       if (!fc->in_ir) {
+       if (G_UNLIKELY(!fc->in_ir || notit->dry_run)) {
                goto end;
        }
 
@@ -2298,6 +2310,11 @@ int64_t bfcr_get_sequence_length_cb(struct ctf_field_class *fc, void *data)
 
        length = (uint64_t) g_array_index(notit->stored_values, uint64_t,
                seq_fc->stored_length_index);
+
+       if (G_UNLIKELY(notit->dry_run)){
+               goto end;
+       }
+
        seq_field = stack_top(notit->stack)->base;
        BT_ASSERT(seq_field);
 
@@ -2319,6 +2336,7 @@ int64_t bfcr_get_sequence_length_cb(struct ctf_field_class *fc, void *data)
                }
        }
 
+end:
        return length;
 }
 
@@ -2381,7 +2399,7 @@ struct ctf_field_class *bfcr_borrow_variant_selected_field_class_cb(
        selected_option = ctf_field_class_variant_borrow_option_by_index(
                var_fc, (uint64_t) option_index);
 
-       if (selected_option->fc->in_ir) {
+       if (selected_option->fc->in_ir && !notit->dry_run) {
                bt_field *var_field = stack_top(notit->stack)->base;
 
                ret = bt_field_variant_select_option_field_by_index(
@@ -2987,3 +3005,10 @@ void bt_msg_iter_set_emit_stream_end_message(struct bt_msg_iter *notit,
 {
        notit->emit_stream_end_msg = val;
 }
+
+BT_HIDDEN
+void bt_msg_iter_set_dry_run(struct bt_msg_iter *notit,
+               bool val)
+{
+       notit->dry_run = val;
+}

diff --git a/src/plugins/ctf/common/msg-iter/msg-iter.h b/src/plugins/ctf/common/msg-iter/msg-iter.h
index b3a129daf27141404092b24ea6376c2413e6585d..7677f770cd2ca6facb98dece2056644de1e330f8 100644 (file)
--- a/src/plugins/ctf/common/msg-iter/msg-iter.h
+++ b/src/plugins/ctf/common/msg-iter/msg-iter.h
@@ -340,6 +340,10 @@ BT_HIDDEN
 void bt_msg_iter_set_emit_stream_end_message(struct bt_msg_iter *notit,
                bool val);
 
+BT_HIDDEN
+void bt_msg_iter_set_dry_run(struct bt_msg_iter *notit,
+               bool val);
+
 static inline
 const char *bt_msg_iter_medium_status_string(
                enum bt_msg_iter_medium_status status)