This change takes the existing typedefs for weight, duration and
distance, and makes them proper types, using the existing Alias
functionality.
Primarily this is to prevent bugs where the metrics are switched,
but it also adds additional documentation. For example, it now
makes it clear (despite the naming of variables) that most of the
trip algorithm is running on the duration metric.
I've not made any changes to the casts performed between metrics
and numeric types, they now just more explicit.
Currently route results are annotated with additional path information,
such as geometries, turn-by-turn steps and other metadata.
These annotations are generated if they are not requested or returned
in the response.
Datasets needed to generate these annotations are loaded and available
to the OSRM process even when unused.
This commit is a first step towards making the loading of these datasets
optional. We refactor the code so that route annotations are only
generated if explicitly requested and needed in the response.
Specifically, we change the following annotations to be lazily generated:
- Turn-by-turn steps
- Route Overview geometry
- Route segment metadata
For example. a /route/v1 request with
steps=false&overview=false&annotations=false
would no longer call the following data facade methods:
- GetOSMNodeIDOfNode
- GetTurnInstructionForEdgeID
- GetNameIndex
- GetNameForID
- GetRefForID
- GetTurnInstructionForEdgeID
- GetClassData
- IsLeftHandDriving
- GetTravelMode
- IsSegregated
- PreTurnBearing
- PostTurnBearing
- HasLaneData
- GetLaneData
- GetEntryClass
Requests that include segment metadata and/or overview geometry
but not turn-by-turn instructions will also benefit from this,
although there is some interdependency with the step instructions
- a call to GetTurnInstructionForEdgeID is still required.
Requests for OSM annotations will understandably still need to
call GetOSMNodeIDOfNode.
Making these changes unlocks the optional loading of data contained in
the following OSRM files:
- osrm.names
- osrm.icd
- osrm.nbg_nodes (partial)
- osrm.ebg_nodes (partial)
- osrm.edges
