Support fs.open() flags being a number vs. string

[tinchoz49]

Hi everyone!

I'm trying to do this and I'm getting flags is not valid:

fs.open("/file.txt", fs.constants.O_RDWR | fs.constants.O_CREAT, function(err, fd) {
  if(err) throw err;
  fs.fstat(fd, function(err, stats) {
    if(err) throw err;
    fs.close(fd);
  });
});

[humphd]

Hey @tinchoz49, this is a bug, thanks for filing. We currently assume flags are in string form ('w+' is closest to what you'd want), and don't yet support passing flags as a bitwise number. We should.

Fixing this would involve making our code do what node does:

• docs where it discusses flags being a String or Number
• code for stringToFlags() in node

A simple fix would be to alter our O_FLAGS object to use numeric keys vs. strings, and convert strings to numbers like node does.

[humphd]

@rscotchmer not sure what you're looking to do for your 0.3 bugs, but this one might be interesting to you. I could mentor you through it, if you have interest. No pressure if you have other things you want to try next.

[CDNRae]

@humphd I'd love to work on this! Thanks for notifying me!

[humphd]

@rscotchmer great, here are some more thoughts.

We currently use strings for flags, and we should switch to using numbers. If a string is passed to us, we should convert it into a number. See the code I linked to above from node, which does what we want.

Next, we do a bunch of checks all over like this: https://github.com/filerjs/filer/blob/master/src/filesystem/implementation.js#L622. Instead of doing this, we'd want to convert that to use the flags number, and bitwise & (and) it with the constant we want to check against. The constants we want are defined in https://github.com/filerjs/filer/blob/master/src/constants.js#L88.

We could start by converting the code in the first comment above into a test we add to the fs.open.spec.js test file, and add more as we go. I have no doubt you'll find other bugs while fixing this, since we probably don't do the right thing in all cases with flags vs. what node does.

Let me know what questions you have, or further help I can give. I'm happy to guide you as you deem necessary.

[tinchoz49]

Hey everyone, thanks to start working on this!