Make decoration provider API public

[sandy081]

Make the following API public

export interface DecorationProvider {
	onDidChangeDecorations: Event<undefined | Uri | Uri[]>;
	provideDecoration(uri: Uri, token: CancellationToken): ProviderResult<DecorationData>;
}

export namespace window {
	export function registerDecorationProvider(provider: DecorationProvider): Disposable;
}

[eamodio]

Instead of DecorationData, what about just Decoration or UriDecoration or ViewDecoration or TreeViewDecoration or something like that?

[jrieken]

Yeah, +1 for Decoration. No matter what we chose it should be aligned with the provide-function name.

[jrieken]

Moving this out because we wanna get a better understand about the requirements. @eamodio Did you look at the existing API proposal and is there anything you need else or different?

[rebornix]

may I ask how does it work for custom tree views? @sandy081 mentioned in #54939 (comment) that it works for file scheme but based on what I test it's not working when the custom tree view item's resourceUri is a file one.

In our pull request extension, when you expand a Pull Request node, we return a list file change nodes, whose resourceUri can be file and we register a decoration provider. The provider works for File Explorer but not custom tree view.

[jrieken]

@sandy081 will know

[sandy081]

@rebornix Out of the box decorations should work when your view item is a file resource. Please create a separate issue with reproducible steps

[rebornix]

@sandy081 I no longer see this issue when running from source code but still saw issues with latest insider. Will report an issue if tomorrow's Insider still has issues with that (I doubt so but let's see).

[eamodio]

Any chance this api is going to progress or be altered? The DecorationData type itself feels more "raw" than many other vscode apis, and I would also love additional filtering rather than just a pure Uri matching -- maybe Uri and optionally a contextValue so that you can target a specific "version" of a Uri without it affecting the main explorer tree?

[jrieken]

so that you can target a specific "version" of a Uri without it affecting the main explorer tree?

Do you have an example for that? Do you want the same uri to have different representations/decorations?

[eamodio]

Yeah, so in a tree I can set the resourceUri of an item to get the file icon/name to show (which also opts me in to any registered decorations on that Uri), but if I want to add a custom decoration for that Uri, but only for my tree (or trees) it would be great to be able to have an optional additional matcher that would use the contextValue of tree item before applying the decoration. That way I could customize entries for my tree without affecting the main explorer (or other representations of that Uri in other trees)

export interface DecorationProvider {
	onDidChangeDecorations: Event<undefined | Uri | Uri[]>;
	provideDecoration(uri: Uri, contextValue: string | undefined, token: CancellationToken): ProviderResult<Decoration>;
}

export namespace window {
	export function registerDecorationProvider(provider: DecorationProvider): Disposable;
}

Alternatively we could provide a read-only TreeItem if there is one, rather than just the contextValue and then an extension could use other context to decide whether or not to apply decorations.

[jrieken]

@eamodio Well, it looks like you do not want to be a file decoration provider (please check latest proposal) but you want decorations for custom trees.

[eamodio]

@jrieken Ideally yeah, but the difference between the two imo is quite blurred.

[jrieken]

• remove badge length check (limit is 2)
• onDidChange options

[jrieken]

fyi @alexr00 I have changed the name of the event from onDidChange to onDidChangeFileDecorations. I might wanna adopt that in GHPR

[alexr00]

@jrieken thanks for the heads up. I have adopted the change.

[jrieken]

@alexr00 sorry one more change for next (tomorrows) insiders: It's now registerFileDecorationProvider to add a provider.

[jrieken]

Done

[sandy081]

Verified that the file decoration provider API is available in vscode.d.ts. and also reviewed the doc.