Sample implementation of embedding theme files

[LordFlashmeow]

Building on #25, here's a sample of how we can embed the theme and filetypes files into the executable.

[sharkdp]

Thank you very much for your contribution!

To be honest, I'd like to avoid doing this. As far as I can see, the only reason would be the packaging difficulties on macOS. I can't really believe that we can not solve this in another way. It should be possible to install a few files to a specified location and load them from there.

[LordFlashmeow]

It's not just packaging difficulties with macOS, but packaging difficulties on every platform. Currently, unless you are using debian or Arch, you need to download the repo and copy the files by hand. As I've discovered, every system is different, and the less we depend on the system, the better.

Cargo doesn't let us copy files to a directory when doing cargo install, we need a full-on package manager to handle that for us instead.

If we embed the files, then it is possible for the average user to download the binary from the releases page and it'll work no matter where they put it. Users can also use cargo install vivid without any further action.

The only time a user would need to add a file to the config directory would be if they wanted to customize one of the themes, and even then they also have the option of specifying the exact file via the command line or an environment variable.

Embedding allows:

• Portable executable
• No setup for majority of users
• Minimal change in binary size (less than .1 MB larger)
• cargo update adds new themes when pushed to repo

[sharkdp]

You have some excellent arguments, thank you. I will give this a review.

[sharkdp]

Rust Embed
Rust Custom Derive Macro which loads files into the rust binary at compile time during release and loads the file from the fs during dev.

Oh, that's pretty cool!

[sharkdp]

Can we remove VividError::CouldNotFindDatabase in that case?

warning: variant is never constructed: `CouldNotFindDatabase`
  --> src/error.rs:15:5
   |
15 |     CouldNotFindDatabase,
   |     ^^^^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(dead_code)]` on by default

[LordFlashmeow]

I think so, although we will need to keep the CouldNotFindTheme error

[sharkdp]

The code changes look great - thank you very much!

[LordFlashmeow]

    let theme = sub_matches
        .value_of("theme")
        .or_else(|| theme_from_env.as_ref().map(String::as_str))
        .unwrap_or("molokai");

In this bit, it looks like we're setting the theme to molokai when unwrapping the environment theme fails there is no environment theme specified. Can we raise an error in that case?

[sharkdp]

In this bit, it looks like we're setting the theme to molokai when unwrapping the environment theme fails. Can we just raise an error in that case?

Yes - sounds good. Thanks

[LordFlashmeow]

Turns out it's checking if no theme is specified. Should that raise an error?

[sharkdp]

Well, for now, vivid generate will use molokai as a default if VIVID_THEME is not set. I'm okay with changing this.

Ideally, we would cover all cases:

• VIVID_THEME unset => vivid generate should throw an error.
• unknown VIVID_THEME => vivid generate should throw an error.
• vivid generate <theme> for unknown <theme> => should throw an error.

[sharkdp]

Thank you for the update!