Handle readonly files

[akosyakov]

• FileStat should have access flags. There should be utility methods to check flags on read, write and execute access
• FileTreeModel should mark file stat nodes without read access as invisible
• Resource should have an explicit optional isReadonly property with default based on the presence of Resource.save method. There should be a utility function to check it.
• FileResource should use FileStat flags to implement isReadonly property
• editor providers should use Resource.isReadonly(resource) to mark editors readonly or not

[hexa00]

I disagree that some files should be invisible you have the right to see them... but an error should be thrown when you try to open ?

[akosyakov]

I meant if the user doesn't have rights to see them he should not see them.

[hexa00]

Then it's the directory that does not have read access and thus you won't be able to get to the file at all...

Otherwise I can see a no permission file with ls without any problems:
---------- 1 x x 0 Jun 13 08:22 testfi

[akosyakov]

PRs are welcomed.

[epatpol]

Would you rather have the fs.modes for the filestat (i.e bitmasks) or easier API like Filestat.isReadable: boolean, isWriteable, isExecutable and so on? Like so:

export interface FileStat {

    /**
     * The uri of the file.
     */
    uri: string;

    /**
     * File access
     */
    isReadable: boolean;
    isWriteable: boolean;
    isExecutable: boolean;

    /**
     * The last modification of this file.
     */
    lastModification: number;

    /**
     * The resource is a directory. Iff {{true}}
     * {{encoding}} has no meaning.
     */
    isDirectory: boolean;

    /**
     * The children of the file stat.
     * If it is undefined and isDirectory is true, then this file stat is unresolved.
     */
    children?: FileStat[];

    /**
     * The size of the file if known.
     */
    size?: number;
}

[akosyakov]

@epatpol Could you check how VS Code handle it? They don't seem to expose such apis, maybe we are overthinking it.

[dpetroff]

In theia 1.36, I set some files to read only on the file system with chmod, and all the resource, filestat, etc. properties all still say that it's not read-only.

It looks to me like DiskFileSystemProvider is entirely oblivious of file permissions:

theia/packages/filesystem/src/node/disk-file-system-provider.ts

Lines 151 to 164 in 4539753

	async stat(resource: URI): Promise<Stat> {
	try {
	const { stat, symbolicLink } = await this.statLink(this.toFilePath(resource)); // cannot use fs.stat() here to support links properly
	return {
	type: this.toType(stat, symbolicLink),
	ctime: stat.birthtime.getTime(), // intentionally not using ctime here, we want the creation time
	mtime: stat.mtime.getTime(),
	size: stat.size
	};
	} catch (error) {
	throw this.toFileSystemProviderError(error);
	}
	}

I think this issue should be reopened.

[msujew]

This issue will be resolved by #12354 instead.