Enables opening read-only files in electron.

[kejsitake]

Signed-off-by: Kejsi Take [email protected]

Fixes: #9860
Makes sure that a user can open a new file in the ElectronFileDialog when it has Read permissions (and not Write).

What it does

• Adds a new canRead() method to check if the user has read permissions to the file.
• Calls the method from .showOpenDialog()

How to test

After making the above-mentioned changes, I ran the Electron example and verified that I could open a file that had only read permissions.

Review checklist

• [ X] as an author, I have thoroughly tested my changes and carefully followed the review guidelines

[tsmaeder]

The code looks good and I've tested that I can open a read-only file on Windows. There is a lot of weird behaviour around reading/writing files into read-only directories on Windows, but the PR fixes the particular problem the issue is about.

[tsmaeder]

@colin-grant-work could you test on Linux?

[msujew]

I could imagine that this could impact performance for large arrays of URIs because every access call is sequential. We can parallelize this fairly well like this:

Suggested change

	for (const uri of Array.isArray(uris) ? uris : [uris]) {
	if (!(await this.fileService.access(uri, FileAccess.Constants.R_OK))) {
	this.messageService.error(`Cannot read resource at ${uri.path}.`);
	return false;
	}
	}
	const filePaths = await Promise.all((Array.isArray(uris) ? uris : [uris]).map(uri => {
	return !await this.fileService.access(uri, FileAccess.Constants.R_OK) && uri.path || '';
	}).filter(e => e);
	if (filePaths.length) {
	this.messageService.error(`Cannot read ${filePaths.length} resources: ${filePaths.join(', ')}`);
	}
	return !!filePaths.length;

[msujew]

Hi @kejsitake, thank you for your first contribution and taking care of this issue 👍

Please be sure to sign the eclipse contributor agreement (eca) with the same email as your authorship in order for us to accept the changes.

[kejsitake]

I think I got the changes done and signed the eca. I am happy to look at this again if needed.

[colin-grant-work]

Code looks good to me and works. One minor comment about naming that may prevent future confusion, but otherwise 👍

[colin-grant-work]

@kejsitake Thank you very much for the contribution!

[msujew]

That looks good to me as well 👍