#!/bin/ksh
# @(#) mkdirlist.ksh 2.0 96/01/19
# 94/10/27 John H. DuBois III (john@armory.com)
# 94/11/15 Added all options.
# 94/11/21 Fixed mount option.  Added -u to sort options.
# 95/09/17 Added a option.
# 96/01/19 Changed default tmpdir to home dir for safety.
# 96/04/09 Added x option.

# Output format: 
# directory-name full-directory-path

lng_name=${0##*/}
Usage="Usage: $lng_name [-adhm] [-o<output-file>] [directory|filename  ...]"
Output=$HOME/.dirs
Mount=-mount
DoFind=true
Append=false
Debug=false

while getopts :ahmdo:x opt; do
    case $opt in
    h)
	echo \
"$lng_name: make a file of directory names suitable for searching with 'look'.
The output file contains one line for each directory, with two words on it. 
The first word is the last directory component; the second is the full path to
the directory (including the last component).  The output file is sorted. 
Because the last component is at the start of the line and the lines are
sorted, the look command can quickly find any directory that begins with a
given prefix.  A file in this format is used by the 'ucd' change-directory
Korn shell function.
$Usage
If a list of directories is given, 'find' is run on them to find all
directories below them.  The -mount flag is included (filesystems mounted
below the named directories will not be searched).  The resulting directory
list is processed as described above and the output is stored in the output
file (\"\$HOME/.dirs\" by default; this is where 'ucd' expects to find it).
If the -d flag is given, the arguments are taken to be files of directory
lists, one directory name per line (as produced by e.g. 'find / -type d').  If
-d is given without any command-line arguments, a list of directories is read
from the standard input.  In either case, the directory lists are processed as
described above and stored in the output file.  If one of the input files is
the same as the output file, it will be read correctly before being
overwritten.
Other options:
-a: Append to the output to the output file, if it already exists.
-h: Print this help.
-m: Do not give the -mount flag to find.
-o<output-file>: Store the output in output-file."
       exit 0
       ;;
    a)
	Append=true
	;;
    o)
	Output=$OPTARG
	;;
    m)
	unset Mount
	;;
    d)
	DoFind=false
	;;
    x)
	Debug=true
	print -u2 "Debugging is on."
	;;
    +?)
	print -u2 "$lng_name: options should not be preceded by a '+'."
	exit 1
	;;
    :) 
	print -r -u2 -- \
	"$name: Option '$OPTARG' requires a value.  Use -h for help."
	exit 1
	;;
    ?) 
	print -u2 "$lng_name: $OPTARG: bad option.  Use -h for help."
	exit 1
	;;
    esac
done
 
# In early ksh, false is an alias and so is not run when a shell var is
# expanded to it; in these versions unalias false returns 0 so can use this as
# a test to make it a function instead, which *is* run when expanded from var.
unalias false && function false { return 1; }

# remove args that were options
let OPTIND=OPTIND-1
shift $OPTIND

if [ $# -lt 1 ] && $DoFind; then
    print -u2 "$Usage\nUse -h for help."
    exit
fi

NZSize=false

: ${TMP:=$TMPDIR}
: ${TMP:=$HOME}
: ${TMP:=/tmp}
if $DoFind; then
    # Catch this because find doesn't care.
    for dir; do
	if [ ! -d "$dir" ]; then
	    print -u2 "$lng_name: $dir is not a directory.  Aborting."
	    exit 1
	fi
    done
    tmpfile=$TMP/#mkdls.$$
    $Debug && set -x
    find "$@" -type d $Mount -print > $tmpfile
    $Debug && set +x
    set -- $tmpfile
    [ -s "$tmpfile" ] && NZSize=true
else
    for file; do
	$Debug && print -u2 "Checking $file"
	if [ ! -a "$file" ]; then
	    print -u2 "$lng_name: cannot access $file.  Aborting."
	    exit 1
	fi
	# Do this test separately from read because read will fail for
	# empty file.
	if [ ! -r "$file" ]; then
	    print -u2 "$lng_name: cannot read $file.  Aborting."
	    exit 1
	fi
	# This is mainly to make sure that we don't try to reprocess a dir list
	# that is already in the output format.
	read a1 a2 < "$file"
	if [ -n "$a2" ]; then
	    print -u2 \
	    "$lng_name: $file is not a plain directory list.  Aborting."
	    exit 1
	fi
	[ -s "$file" ] && NZSize=true
    done
fi

# Don't overwrite old output file (if any) if we won't put anything in it.
$NZSize || {
    print -u2 "$lng_name: no directory names to process.  Aborting."
    exit 1
}

PATH=$PATH:/usr/local/bin	# make sure we can find gawk

$Append && OtherFiles=$Output || OtherFiles=

# Usage gawk because its %c works the way we want
gawk -F/ '
BEGIN {
    for (i = 1; i <= 32; i++)
	BadPat = BadPat sprintf("%c",i)
    BadPat = "[" BadPat sprintf("%c",127) "]"
}

# Ignore any dirs that have control chars or spaces in them.
# Control chars are liable to muck up prompt if it includes $PWD,
# spaces will confuse routines that search/use this file.
$0 !~ BadPat {
    printf "%s %s\n",$NF,$0
}
' "$@" | sort -u -o $Output - $OtherFiles

$DoFind && rm $tmpfile