Coding Conventions

This page summarizes the coding conventions used for RST.

Generally, data types are described using the Google Protocol Buffers IDL syntax and hence the proposed conventions for this language apply. They can be found in the Google Protocol Buffers Style Guide.

Apart from the general conventions we apply the following ones:

Note

The source code is continuously checked against these conventions using the CI server. Results of the checks can be found at: https://ci.cor-lab.org/view/rst/job/rst-trunk-static-analysis/

Naming

• Do not include a description of a particular communication pattern in the name of a data type. For example, if you currently send events containing images, your data type must not be called ImageEvent, but Image, as the name Image would also be suitable for other patterns like RPC communication.
• The Google Protocol Buffers option java_outer_class_name has to specified and its value has to be of the form TYPE-NAMEType. For example, the correct value for Image is ImageType.

Directory and File Layout

• The directory (relative to the proto/{stable,sandbox} directory in the project root) in which the proto-file resides must match the package name with all ”.”s replaced with “/”s.
• The filename must match the name of the “primary” message definition (with ”.proto” appended).
• There should only be one “primary” message definition in each proto-file.
  • Groups of related messages should reside in individual files and refer to each other using the import directive.
• Directory names are all lowercase and without word separations, e.g. imageprocessing.
• imports are always performed using absolute paths starting from the rst package, e.g. import "rst/vision/Image.proto";.

Rationale

• Facilitate easy documentation and reuse via import.
• Data type definitions can be treated as resources with unique URLs in e.g. a repository browser.

Example

In case you define a data type named MyData which logically belongs to the foo package, the containing file has to contain the package declaration package rst.foo; in the first line and must reside in the directory proto/{stable,sandbox}/rst/foo with the name MyData.proto.

File Content Structure

Each file is constructed as follows:

1. package declaration on first line
2. import statement(s)
3. option statement(s)
4. Message definition(s)

Indentation and White Spaces

• Indentation is performed exclusively using spaces (not tabs).
• Indentations are always multiples of 4 spaces.
• There must be no have trailing spaces.
• Each file ends with a newline.
• File-wide declarations like package, import or option statements must not be indented.
• All text inside message and enum definitions are indented by 4 spaces.
• Curly braces are placed on the same lines as the corresponding message or enum keywords. The closing curly brace is on a separate line.
• All elements are at a maximum separated by one empty line.