ImportCache

Remarks

This is what resolves the cache key's chicken and egg. The key includes the artefact ids of everything the import depended on — and what it depends on is only known once it has run. So the key is computed from the dependencies the previous import declared: if they have not changed, neither has the answer, and the import is skipped; if any of them has, the key differs and the import runs, declaring a fresh set as it goes.

A newly-declared dependency is therefore respected from the second import onwards, not the first — which is exactly right, because the first import is the one that ran and produced a correct artefact. Every incremental build system reaches this answer; it is worth writing down because it looks like a bug until it is stated.

Tab-separated text, like the GUID index it sits next to. It lives in Library/, so it is never committed and never has to be compatible with anything — and a hundred thousand entries of it are read line by line rather than parsed as one document.

Fields and properties (2)

• public int Count

  How many assets have a record.

• public IReadOnlyCollection<ImportRecord> Records

  Every record.

Methods (5)

• public bool TryGet(AssetId asset, out ImportRecord? record)

  Looks up what an asset's last import produced.

• public void Set(ImportRecord record)

  Records an import.

• public bool Forget(AssetId asset)

  Forgets an asset, so its next import runs.

• public void Save(string path)

  Writes the cache.

• public bool TryLoad(string path)

  Reads the cache back, if it is there.

Used by (12)

• BuildPlannerVixen.Editor.Assets
• ContentTasksVixen.Editor.App
• DoctorRunnerVixen.Cli
• EditorContentVixen.Editor.App
• ImportPipelineVixen.Editor.Assets
• ImportPipelineTestsVixen.Editor.Assets.Tests
• LooseContentTestsVixen.Editor.Assets.Tests
• PlannedProjectVixen.Editor.Assets.Tests
• ProjectVixen.Cli
• ProjectMeshSourceVixen.Editor.Assets
• ProjectSurfaceSourceVixen.Editor.Assets
• ProjectWorkspaceVixen.Editor.Assets