Cell statusbar API

[roblourens]

Fix #105809

Much better implementation of the cell statusbar API.

Open questions/todos

• Do extensions need to show items that are only visible when the cell is active? Should I just call the providers again when the cell becomes active?
• Need to debounce statusbar updates when scrolling?
• Any other cases when providers should be called? The only case when the provider is canceled is when the item scrolls out of view during an update, is that right?
• The service is kind of pointless here, would it be better to just expose a list of providers, basically a provider registry?
• Get other internal things onto this API, and remove statusMessage metadata
• Fix bugs like Notebook cell status bar lacks left padding #115099 and Notebook cell placeholder text should be updated for Markdown cells #112772

[rebornix]

I added a simple notebook cell status bar items provider like

	vscode.notebook.registerNotebookCellStatusBarItemProvider({
		viewType: 'mimetype-test'
	}, {
		provideCellStatusBarItems: (cell, token) => {
			return [{
				alignment: vscode.NotebookCellStatusBarAlignment.Left,
				command: undefined,
				text: `${cell.outputs.length} outputs`,
				tooltip: `${cell.outputs.length} outputs`
			}];
		}
	})

and after scrolling up and down a couple of times. I'm seeing duplicated status bar items.

[rebornix]

this change is not intentional, right? it's still a decoration id.

[rebornix]

I see this one is being used for cell status bar. I wonder if we should keep decoration and status bar logic separate.

[roblourens]

I figured I'd reuse it, but it doesn't matter, I can keep it separate

[rebornix]

Need to debounce statusbar updates when scrolling?

It would be great if we debounce it a bit as while scrolling / cell resizing (as they have dynamic height), a cell can be created, disposed and then re-created within a short period.

[roblourens]

a cell can be created, disposed and then re-created within a short period.

What do you mean?

The downside of delaying it is that you will see cells without status bar items briefly, then the status bar items will blink into existence, and I found it annoying when testing.

[roblourens]

Fixed the issue with dupe items showing up, I thought a cancel token would be canceled on dispose by default.

[jrieken]

mix of ? and | undefined

[jrieken]

missing dispose?

[jrieken]

Only skimmed over the view-parts but what I have seens looks good. Thanks

[jrieken]

The service is kind of pointless here, would it be better to just expose a list of providers, basically a provider registry?

Services are always better than singletons, tho that's all they are: better singletons