bash-completion: add completion script

[audeoudh]

Confer #260.

[ebiggers]

Thanks, a few comments. It's hard to review this without experience writing bash completion scripts, though.

[ebiggers]

I think I'm finally understanding most of this, but it's difficult to read because of the code duplication with the bash-completion boilerplate. Could you add some helper functions like:

_fscrypt_complete_mountpoint()                                                   
{                                                                                
    COMPREPLY=($(compgen -W "$(_fscrypt_mountpoints)" -- "$cur"))                
}

_fscrypt_complete_word()                                                         
{                                                                                
    local wordlist=$1                                                            
                                                                                 
    COMPREPLY=($(compgen -W "$wordlist" -- "$cur"))                              
}                                                                                
                                                                                 
_fscrypt_complete_option()                                                       
{                                                                                
    local additional_opts=${1-}                                                  
    local GLOBAL_OPTS="--verbose --quiet --help"                                 
                                                                                 
    _fscrypt_complete_word "$additional_opts $GLOBAL_OPTS"                       
}                                                                                

... and use them everywhere where they can. Also, please use if instead of case when there are only two branches.

That should make things a lot easier to understand.

E.g. the following:

        case $cur in
            -*)
                COMPREPLY=($(compgen -W "--time= --force ${GLOBAL_OPTS}" \
                           -- "${cur}"))
                ;;
            *)
                COMPREPLY=($(compgen -W "$(_fscrypt_mountpoints)" -- "${cur}"))
                ;;
        esac

... would become:

        if [[ $cur == -* ]]; then
            _fscrypt_complete_option "--time= --force"
        else
            _fscrypt_complete_mountpoint
        fi

[ebiggers]

Also, please squash your commits into one. Thanks!

[audeoudh]

I mainly:

• changed “too simple” case structures to if/else blocks,
• added functions for conceptualize bash-completion typical code,
• added more comments in the script,
• added the script in make lint and make install.
• squashed commits

Let me know if there is still something to do.

[ebiggers]

It looks much better now, thanks. Can you address the two comments I just left (remove --drop-caches, and update make uninstall)? Afterwards I think this will be ready to merge, unless @josephlr has comments.

[ebiggers]

Thanks, merged now.