How can I selectively disable zsh's version control integration when my CWD is on a remote filesystem?

Question

I'm running zsh on OSX and on occasion I have to work on a mounted sshfs volume. However, git is REALLY slow over sshfs mounts. My prompt makes use of the vc mode stuff that zsh provides built in, but in this case I want to skip that part.

I'd like to selectively disable vc integration any time my CWD is on a mounted filesystem. How can I do that?

I'm currently enabling git info in my prompt using (roughly) this snippet of my .zshrc (well, .oh-my-zsh/themes, but you get the idea):

zstyle ':vcs_info:*' enable hg git bzr svn p4

zstyle ':vcs_info:(hg*|git*):*' get-revision true
zstyle ':vcs_info:(hg*|git*):*' check-for-changes true

# rev+changes branch misc
zstyle ':vcs_info:hg*' formats "[%i%u %b%m]"
zstyle ':vcs_info:hg*' actionformats "(%{$fg_bold[red]%}%a%{$reset_color%})[%i%u %b%m]"

# hash changes branch misc
zstyle ':vcs_info:git*' formats "[%{$fg[yellow]%}%12.12i%{$reset_color%} %u %{$fg[magenta]%}%b%{$reset_color%}%m]"
zstyle ':vcs_info:git*' actionformats "(%a)[%{$fg[yellow]%}%12.12i%{$reset_color%} %u %{$fg[magenta]%}%b%{$reset_color%}%m]"

zstyle ':vcs_info:git*+set-message:*' hooks git-st git-stash

zstyle ':vcs_info:hg*:netbeans' use-simple true

zstyle ':vcs_info:hg*:*' get-bookmarks true

zstyle ':vcs_info:hg*:*' get-mq true
zstyle ':vcs_info:hg*:*' get-unapplied true
zstyle ':vcs_info:hg*:*' patch-format " mq(%g):%{$fg[green]%}%n%{$reset_color%}/%{$fg_bold[blue]%}%c%{$reset_color%} %{$fg[green]%}%p%{$reset_color%}"
zstyle ':vcs_info:hg*:*' nopatch-format ""

zstyle ':vcs_info:hg*:*' unstagedstr " ?"
zstyle ':vcs_info:hg*:*' hgrevformat "%{$fg[yellow]%}%r%{$reset_color%}" # only show local rev.
zstyle ':vcs_info:hg*:*' branchformat "%{$fg[magenta]%}%b%{$reset_color%}" # only show branch

# Show remote ref name and number of commits ahead-of or behind
function +vi-git-st() {
    local ahead behind remote
    local -a gitstatus

    # Are we on a remote-tracking branch?
    remote=${$(git rev-parse --verify ${hook_com[branch]}@{upstream} \
        --symbolic-full-name 2>/dev/null)/refs\/remotes\/}

    if [[ -n ${remote} ]] ; then
        # for git prior to 1.7
        # ahead=$(git rev-list origin/${hook_com[branch]}..HEAD | wc -l)
        ahead=$(git rev-list ${hook_com[branch]}@{upstream}..HEAD 2>/dev/null | wc -l | tr -s ' ')
        (( $ahead )) && gitstatus+=( " ${c3}+${ahead}${c2}" )

        # for git prior to 1.7
        # behind=$(git rev-list HEAD..origin/${hook_com[branch]} | wc -l)
        behind=$(git rev-list HEAD..${hook_com[branch]}@{upstream} 2>/dev/null | wc -l | tr -s ' ')
        (( $behind )) && gitstatus+=( " ${c4}-${behind}${c2}" )

        hook_com[branch]="${hook_com[branch]} [${remote}${(j:/:)gitstatus}]"
    fi
}

# Show count of stashed changes
function +vi-git-stash() {
    local -a stashes

    if [[ -s ${hook_com[base]}/.git/refs/stash ]] ; then
        stashes=$(git stash list 2>/dev/null | wc -l)
        hook_com[misc]+=" (${stashes} stashed)"
    fi
}

precmd () { vcs_info }
PROMPT='
%{$(get_prompt_user_color)%}%n%{$reset_color%} at %{$(get_prompt_host_color)%}%m%{$reset_color%} in %{$fg_bold[green]%}%~%{$reset_color%} ${vcs_info_msg_0_}
$(virtualenv_info)$(prompt_char) '

Answer 1

Have a look at Version-Control-Information

Search for the section on 'disable-patterns' (roughly 20% down the page).
Assuming your remote mounts are fixed, or relatively fixed, i.e. /mnt/remote/* or you can list them all, you should be able to come up with a regex for them.

The example at the link is disabling vcs_info under ~/.zsh/, via:

zstyle ':vcs_info:*' disable-patterns "$HOME/.zsh(|/*)"

I guess you could make the zshrc or equivalent (sorry - bash user) figure out which are remote at startup (or periodically, or ...) and update the zstyle accordingly.