Detect Darwin with lighter method

[delphinus]

The plugin is detecting Darwin by system uname command. But the system() call is too slow, and I noticed it makes the starting method slow, also. In this PR, has('macunix') is used for detecting Darwin instead of system() call.

You can see this with +profile feature.

vim --cmd "profile start profile.txt" --cmd "profile file /path/to/plugin/webdevicons.vim" +q && vim profile.txt

SCRIPT  /path/to/plugin/webdevicons.vim
Sourced 1 time
Total time:   0.286557
 Self time:   0.001238

count  total (s)   self (s)
                            " Version: 0.7.0
                            " Webpage: https://github.com/ryanoasis/vim-devicons
                            " Maintainer: Ryan McIntyre <[email protected]>
                            " License: see LICENSE

    1              0.000003 let s:version = '0.7.0'
    1   0.284813   0.000301 let s:operatingsystem = system("uname -s")

                            " standard fix/safety: line continuation (avoiding side effects) {{{1
                            "========================================================================

...

• Mac OS X 10.11.2
• Vim 7.4.972 (MacVim snapshot 87)

Vim took 0.286557 second with its loading, and system("uname -s") occupied most of it, 0.284813 second.

[ryanoasis]

Thanks! This looks interesting and like a good improvement. I just upgraded so the difference seems negligible to me but I will try on my old laptop.

Any ideas of has('macunix') vs has('mac') ?
seems like the former is for detecting a bit 'newer' mac os.

Ah here we go:

mac             Macintosh version of Vim.
macunix         Macintosh version of Vim, using Unix files (OS-X).

So... 'macunix' is probably the one to go with (OSX) I think 😄

Do you know anything about the reliability of this vs the system call?

I will read up on this more. So far looks like this would be a good change...

[delphinus]

Sorry, I was mistaken. has('mac') or has('macunix') means it to be built as MacVim. So both are false in a normal vim such as /usr/bin/vim even if on OS X Darwin.

After all, we have to call uname for detecting OS correctly, but it took a bit time. The starting time of my Vim doubled with this plugin. My suggestion for detecting OS logic is below...

1. If has('macunix'), it is Darwin.
2. If not has('macunix') and has('unix'), call uname -r.
3. If output is Darwin, it is Darwin. If not, it is other unix system such as Linux.
4. system() call will take a bit time. If you want to avoid this, you should set a variable (ex. g:devicons_operating_system) to detect OS without calling system().

I will rewrite PR for this logic.

[delphinus]

Updated. I added a config value g:WebDevIconsUseSystemCallToDetectOS. Please review this.

[ryanoasis]

Sorry for long delay. Overall I like this change but have some questions and feedback.

The 2nd conditional seems a little odd to me. Couldn't it be eliminated if g:WebDevIconsUseSystemCallToDetectOS was used in the third conditional.

I think by default the system call should be done if we still aren't 100% from the info from feature-list

Maybe instead of g:WebDevIconsUseSystemCallToDetectOS being an on|off it could be a string to allow the user to just specify the system they are on and thus even avoid the system call when it is set. With this I think the system call will only fire if: unix file format and not mac vim and the variable not set. Also we could move the detection call so it doesn't fire for Dos fileformat. Thoughts?

[delphinus]

Indeed. It is useless that system() call if the file is not ff=unix or if the plugin already knows OS. So I will change logic such below.

1. I will add a variable g:WebDevIconsOS. This is not defined in default.
2. If you open a file of ff=dos or ff=mac, it doesn't care.
3. If you open a file of ff=unix,
   • If has('macunix'), the plugin use Apple Logo.
   • If g:WebDevIconsOS is defined, the plugin use this. When it is Darwin, use Apple Logo. When other, use Linux Logo.
   • If g:WebDevIconsOS is not defined, the plugin call system('uname -r') to detect OS.

[delphinus]

Updated. Should I explain about g:WebDevIconsOS in README?

[ryanoasis]

Awesome. Glad you agreed 😃

Feel free to add it to the readme, just know I might tweak it.

Thanks.

[ryanoasis]

feel free to test this out in 0.8.0 branch

Not fully tested but seems stable

[delphinus]

readme updated. Please correct expression, if needed.