simplify variable expansions

[etc/zsh.git] / .zsh / zshrc / 60_vcsprompt

# zshrc/60_vcsprompt
#
# Make git information available to the prompt
#
# Copyright © 1994–2008 martin f. krafft <madduck@madduck.net>
# Released under the terms of the Artistic Licence 2.0
#
# Source repository: http://git.madduck.net/v/etc/zsh.git
#
# Shamelessly based on http://glandium.org/blog/?p=170
#

__git_get_reporoot()
{
  # return the full path to the root of the current git repository
  [ -d "$GIT_DIR" ] && echo "$GIT_DIR" && return 0
  local relroot
  relroot="$(git rev-parse --show-cdup 2>/dev/null)" || return 1
  if [ -n "$relroot" ]; then
    readlink -f "$relroot"
  else
    echo $PWD
  fi
}

__git_get_branch()
{
  # return the name of the git branch we're on
  local ref
  ref=$(git symbolic-ref -q HEAD 2>/dev/null \
     || git-name-rev --name-only HEAD 2>/dev/null) || return 1
  echo "${ref#refs/heads/}"
}

__hg_get_reporoot()
{
  hg root
}

__hg_get_branch()
{
  echo "hg:$(hg branch)"
}

__bzr_get_reporoot()
{
  local reporoot
  reporoot="$(bzr info | sed -rne 's, *branch root: ,,p')"
  case "$reporoot" in
    .) echo "$PWD";;
    *) echo "$reporoot";;
  esac
}

__bzr_get_branch()
{
  local branch revno
  bzr version-info | while read i j; do
      case "$i" in
        revno:) revno="$j";;
        branch-nick:) branch="$j";;
      esac
    done
  echo "bzr:${branch}@$revno"
}

__vcs_get_repo_type()
{
  # return the type of the closest repository in the path hierarchy
  local dir
  while true; do
    [ -d ${dir}.git ] && echo git && break
    [ -d ${dir}.bzr ] && echo bzr && break
    [ -d ${dir}.hg ] && echo hg && break
    [ "$(readlink -f ${dir:-.})" = / ] && echo NONE && break
    dir="../$dir"
  done
}

__vcs_get_prompt_path_components()
{
  # return formatted path components (prefix branch postfix) given
  # the repository root and the branch.

  # shortcut: if there are no arguments, return a default prompt
  if [ -z "${1:-}" ]; then
    pwdnamed="${(%):-'%${_PROMPT_PATH_MAXLEN}<..<%~%<<'}"
    echo "$pwdnamed"
    return
  fi

  local reporoot branch
  reporoot="${1%%/}"
  branch="$2"

  # replace named directories in the PWD, we need thi for the proper component
  # count later
  local pwdnamed
  pwdnamed="${(%):-%~}"

  # store paths in arrays for component count calculation
  typeset -la apwd apwdnamed areporoot
  apwd=(${(s:/:)PWD})
  apwdnamed=(${(s:/:)pwdnamed})
  areporoot=(${(s:/:)reporoot})

  # get the number of leading and trailing path components. Since we're using
  # %~ later and then /home/madduck suddenly becomes ~, which is 1, not
  # 2 components, we calculate the leading component count by using the named
  # path and the number of post components
  local precomps postcomps
  postcomps=$(($#apwd - $#areporoot))
  precomps=$(($#apwdnamed - $postcomps))

  local postfix
  (( $postcomps > 0 )) && postfix="${(%):-'%${postcomps}~'}"

  # we don't want the prompt to get too long, so keep the total prompt length
  # under $_PROMPT_PATH_MAXLEN (25), but ensure that the prefix is not shorter
  # than $_PROMPT_PATH_MINLEN (10), no matter what
  local prelen minlen prefix
  prelen=$((${_PROMPT_PATH_MAXLEN:-25} - $#branch - $#postfix))
  minlen=${_PROMPT_PATH_MINLEN:-10}
  (( $prelen < $minlen )) && prelen=$minlen
  prefix="${(%):-'%${prelen}<..<%-${precomps}~%<<'}"

  echo "'$prefix'" "'$branch'" "'$postfix'"
}

__vcs_set_prompt_variables()
{
  # set psvar[1..3] depending on repo type, or just psvar[1] if no repo found
  local reporoot branch repotype
  repotype="${1:-$(__vcs_get_repo_type)}"

  case "$repotype" in
    git)
      reporoot="$(__git_get_reporoot)" ||
        { error "could not determine git repository root"; return 1 }
      branch="$(__git_get_branch)" ||
        { error "could not determine git branch"; return 1 }
      eval set -- $(__vcs_get_prompt_path_components "$reporoot" "$branch")
      [ -d "$GIT_DIR" ] && set -- "$GIT_DIR" "$2" "$1"
      ;;
    hg)
      reporoot="$(__hg_get_reporoot)" ||
        { error "could not determine hg repository root"; return 1 }
      branch="$(__hg_get_branch)" ||
        { error "could not determine hg branch"; return 1 }
      eval set -- $(__vcs_get_prompt_path_components "$reporoot" "$branch")
      ;;
    bzr)
      reporoot="$(__bzr_get_reporoot)" ||
        { error "could not determine bzr repository root"; return 1 }
      branch="$(__bzr_get_branch)" ||
        { error "could not determine bzr branch"; return 1 }
      eval set -- $(__vcs_get_prompt_path_components "$reporoot" "$branch")
      ;;
    *)
      case "$repotype" in
        NONE) :;;
        *) warn "$repotype repositories not (yet) supported in the prompt";;
      esac
      local p="%${MAXLEN}<..<%~%<<"
      #TODO find a better way so we don't have to nuke $psvar, but since the
      #     %(nv.true.false) check for prompts checks element count, not
      #     content, that's all we get for now
      psvar=("${(%)p}")
      return
  esac

  psvar[1,3]=($1 $2 $3)
}

if ! is_root; then
  # too dangerous to be run as root

  _update_vcs_prompt_vars_if_vcs_ran() {
    local vcs="$(__vcs_get_repo_type)"
    case "$(history $(($HISTCMD - 1)))" in
      # $vcs appeared in last command, so be sure to update
      *${vcs}*) __vcs_set_prompt_variables "$vcs"
    esac
  }
  precmd_functions+=_update_vcs_prompt_vars_if_vcs_ran

  _update_vcs_prompt_vars() {
    __vcs_set_prompt_variables
  }
  chpwd_functions+=_update_vcs_prompt_vars

  # call it once
  _update_vcs_prompt_vars
fi

# vim:ft=zsh