README.md

nexus-writer source code description

This file explains the nexus-writer source code file structure.

Top-Level Modules

main.rs

This module operates in a similar way to other components, containing the clap Cli structure.

message_handlers.rs

Consists of functions which bridge the main main module and run_engine.

flush_to_archive.rs

Implements

error.rs

run_engine.rs

Manages the run cache, accepts flatbuffer messages via the message_handler module and passes them to the appropriate run object.

hdf5_handlers.rs

Extension Traits for hdf5 objects.

nexus

Defines general structs and traits used in the nexus_structure module.

nexus_structure

This is where the nexus file structure is found, files and directories are set out in a way that roughly follows the group structure of the nexus format.

Lower-Level Modules

nexus.rs

Defines the NexusSchematic trait which is implemented by every struct in the nexus_structure module. This trait standardises the creating and opening of the appropriate fields in nexus files.

Defines the NexusMessageHandler<M> trait which takes a generic M. This trait is implemented by structs in nexus_structure module which process messages M.

Defines the NexusGroup<S> struct which takes a generic S : NexusSchematic. This struct is a wrapper around the structs defined in the nexus_structure module.

Note that for every S : NexusSchematic which implements NexusMessageHandler<M>, NexusGroup<S> automatically implements NexusMessageHandler<M> and passes M to S.

file_interface.rs

This defines a trait which abstracts the hdf5 file functionality. This interface is injected into the Run object. This allows the hdf5 file to be mocked in unit tests.

logs.rs

This defines the LogMessage and AlarmMessage traits which are implemented on appropriate types of log message (e.g. flatbuffer logs). This trait allows performs tasks such as getting the approprate type_description for the message, or writing its time/value to a given Dataset.

classes.rs

Implements the enum NexusClass which standardises the adding of attributes specifying the nexus classes of groups.

units.rs

Implements the enum NexusUnits which standardises the adding of attributes specifying physical units.

nexus_structure.rs

Defines the Root struct which is the top level of the nexus format.

entry.rs

Defines the Entry struct which contains most of the fields, and implements NexusSchematic for it.

event_data.rs

Defines the EventData struct, and implements NexusSchematic for it.

runlog.rs

Defines the RunLog struct, and implements NexusSchematic for it.

RunLog maintains a HashMap of NexusGroup<Log> keyed by String.

selog.rs

Defines the SELog struct, and implements NexusSchematic for it.

RunLog maintains a HashMap of NexusGroup<ValueLog> keyed by String.

logs

Defines the Log, ValueLog and AlarmLog structs which are used in runlog.rs and selog.rs, and implements NexusSchematic for them.

The struct ValueLog consists of Option<Log> and Option<AlarmLog> fields.