Purpose

This PR adds a new ExtensionStorage interface which can be implemented on Extensions and ViewExtension to give the author of the extension the possibility to store extension data directly in the DYN file.

The interface adds two new methods OnWorkspaceOpen and OnWorkspaceSaving which are triggered when a graph is opened and when its saved. Both methods passes a Dictionary<string,string> which can be used to store extension data in, OnWorkspaceSaving also passes a SaveContext so the implementer can react to different save contexts (i.e. save, save as).

The WorkspaceModel stores a collection of ExtensionData objects which is serialized to the DYN file on save. The OnWorkspaceOpen passes a copy of the extension data dictionary therefor modifications done to this will not be reflected in the ExtensionData object (FYI @saintentropy). OnWorkspaceSaving passes a direct reference to the ExtensionData objects dictionary and there for modification made to this will be reflected in the DYN file.

TODO

• Determine the max size of the dictionary stored in the DYN file
• Add extension version to the ExtensionData model

Declarations

Check these if you believe they are true

• The codebase is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.
• This PR modifies some build requirements and the readme is updated

Reviewers

@saintentropy
@nate-peters

FYIs

@mjkkirschner
@QilongTang