tree c02085f5278bf8d4008fd653628701b398af0dbd
parent 3b58ef4ffabfd9df2ecc612eabf942da7a241048
author Christophe Bedard <bedard.christophe@gmail.com> 1555386736 -0400
committer Christophe Bedard <bedard.christophe@gmail.com> 1556225526 -0400

ros: add message flow analysis

From the ROS queues view, the user can select a message from a queue,
which will trigger the message flow analysis. This analysis computes
the path of that message through ROS nodes, including pub/sub queues
and callbacks. It depends on three analyses:

1. (Existing) queues analysis, for all the information about the
   state of queues and callbacks.
2. Connections model, which provides a list of ROS connections (e.g.
   pub/sub) between nodes. Note: services are not supported yet.
3. Messages transport analysis, itself depending on the connections
   model. It uses this model along with a ROS-specific extension of
   TmfEventMatching to try to link every message that gets sent over
   the network (by a publisher) to a message that is received on the
   other side (by a subscriber) in order to build a flow graph.

Its current limitations, which should eventually be addressed, are:

1. At this moment, it assumes that the flow graph is linear, i.e. one
   input message in a callback leads to, at most, one published
   message.
2. It currently only builds a graph for the selected message, and only
   builds it going forward.

Eventually, this should be used/extended to create a ROS-aware
critical path analysis.

Change-Id: I2effd8d74143f5431b713cb034119746fa7708b5
Signed-off-by: Christophe Bedard <bedard.christophe@gmail.com>
Reviewed-on: https://git.eclipse.org/r/140644
Tested-by: CI Bot
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>