Improve shorten_path script

usr/bin/shorten_path

@@ -1,46 +1,74 @@
-#!/bin/sh
+#!/usr/bin/zsh -f
 #
-# Shorten path according to hashed dir list ('hash -d' in Zsh)
-# It also replaces $HOME with ~.
+# Shorten path according to hashed dir list ('hash -d' in Zsh),
+# maintained in ~/.dotfiles/oh-my-zsh/lib/hash_dirs.
+# This also replaces $HOME with ~.
 #
 # This is used from vimrc.
 
-# TODO: relative to current dir?! currently done by Vim
+# Plain sh would be ~4x faster on startup, but with cat/sed etc similar slow/fast,
+# and needs a cache file.
+#!/bin/sh
+
+# Self-tests: run with '--test'. {{{
+tests() {
+  hash -d df=~/.dotfiles
+
+  set -x -e
+  cd ~
+  [[ $(shorten_path .dotfiles/vimrc) == '~df/vimrc' ]]
+
+  cd .dotfiles
+  [[ $(shorten_path ~/.dotfiles/vimrc) == 'vimrc' ]]
+  [[ $(shorten_path vimrc) == 'vimrc' ]]
+  [[ $(shorten_path ../.dotfiles/vimrc) == 'vimrc' ]]
+
+  [[ $(shorten_path ~/.dotfiles/foo/bar) == 'foo/bar' ]]
+  [[ $(shorten_path foo/bar) == 'foo/bar' ]]
+  [[ $(shorten_path ../.dotfiles/foo/bar) == 'foo/bar' ]]
+
+  # With "base" dir.
+  cd ~
+  [[ $(shorten_path .dotfiles/vimrc $PWD) == '~df/vimrc' ]]
+  [[ $(shorten_path vimrc .dotfiles) == 'vimrc' ]]
+  [[ $(shorten_path ~/.dotfiles/vimrc /) == '~df/vimrc' ]]
+
+  cd .dotfiles
+  [[ $(shorten_path ../.vimrc) == '../.vimrc' ]]
+  [[ $(shorten_path ../non-existent) == '../non-existent' ]]
+
+  set +x
+  time ( for i in {1..200}; do shorten_path foo; done )
+}
+if [ x$1 = 'x--test' ]; then
+  tests
+  return
+fi
+# }}}
+
+if [ -z "$1" ]; then
+  echo "Argument (path) required." >&2
+  exit 1
+fi
 
 path="$1"
+if [ -n "$2" ]; then
+  cd "$2"
+fi
 
-hash_file=$HOME/.cache/hashd
+source ~/.dotfiles/oh-my-zsh/lib/hash_dirs.zsh
+test -f ~/.dotfiles/oh-my-zsh/lib/hash_dirs.local.zsh && source ~/.dotfiles/oh-my-zsh/lib/hash_dirs.local.zsh
 
-# Regenerate hash cache file, if zshrc/zshrc.local (which contains hash
-# commands) is newer.
-# if ! [ -f $hash_file ] || [ $(( $(date +%s) - $(stat -c %Y $hash_file) )) -gt 86400 ]; then
-if ! [ -f $hash_file ] || [ ~/.zshrc -nt $hash_file ] || [ ~/.zshrc.local -nt $hash_file ]; then
-  # Generate list, sorted by length (so ~omz gets shortened instead of ~df/oh-my-zsh).
-  # zsh -i -c 'hash -d' | awk '{print length, $0;}' | sort -nr | cut -d\  -f2- > $hash_file
+# dir=${path:h:a}
 
-  # Use a temporary file to only get the output from "hash -d".
-  (cd /tmp \
-    && t=$(mktemp) \
-    && zsh -i -c "hash -d > $t" 2>/dev/null \
-    && awk '{print length, $0;}' $t | sort -nr | cut -d\  -f2- > $hash_file)
+abs_path=${path:a}
+# Keep relative dirs, which are not going back to below base/$PWD.
+if [[ $path = ../* ]] && [[ $abs_path != $PWD/* ]]; then
+  printf $path
+  return
 fi
 
-set -f  # Disable path globbing, in case there's '*' in the cache file.
-IFS='
-'
-for line in $(cat $hash_file); do
-  var=${line%%=*}
-  val=${line#*=}
-  # Skip any unexpected lines.
-  [ "$var" != "$line" ] && [ "$val" != "" ] || continue
-
-  # TODO: match only at beginning?!
-  # echo "$var => $val"
-  new=${path#$val}
-  if [ "$new" != "$path" ]; then
-    new="~$var$new"
-    echo -n $new
-    exit
-  fi
-done
-echo -n $path | sed "s:^$HOME:~:"
+pwd_short=${(D)PWD}/
+path_short=${(D)abs_path}
+printf ${path_short#$pwd_short}
+exit