#!/bin/bash

makelinks() { (
  local volume=$1
  local file=$2  # ignored in this version
  echostep Making as many links as possible on $volume
  # Iterate until the ln command fails
  set -e
  cd $volume
  mkdir -p links
  for a in 0 1 2 3 4 5 6 7 8 9 ; do
    for b in 0 1 2 3 4 5 6 7 8 9 ; do
      echo making 10,000 pairs of hard-linked files ...
      mkdir -p links/$a$b
      for c in 0 1 2 3 4 5 6 7 8 9 ; do
        for d in 0 1 2 3 4 5 6 7 8 9 ; do
          mkdir -p links/$a$b/$c$d
          for e in 0 1 2 3 4 5 6 7 8 9 ; do
            for f in 0 1 2 3 4 5 6 7 8 9 ; do
              file=links/$a$b/$c$d/$e$f
              touch ${file}a
              ln    ${file}a ${file}b
            done
          done
        done
      done
    done
  done
) }

makelinksAllToOneFile() { (
  local volume=$1
  local file=$2
  echostep Making as many links as possible on $volume
  # Iterate until the ln command fails
  set -e
  cd $volume
  mkdir -p links
  for a in 0 1 2 3 4 5 6 7 8 9 ; do
    for b in 0 1 2 3 4 5 6 7 8 9 ; do
      echo making 10,000 hard links ...
      mkdir -p links/$a$b
      for c in 0 1 2 3 4 5 6 7 8 9 ; do
        for d in 0 1 2 3 4 5 6 7 8 9 ; do
          mkdir -p links/$a$b/$c$d
          for e in 0 1 2 3 4 5 6 7 8 9 ; do
            for f in 0 1 2 3 4 5 6 7 8 9 ; do
              ln -f $file links/$a$b/$c$d/$e$f
            done
          done
        done
      done
    done
  done
) }

createRamVolume() {
  #!/bin/sh
  # Copyright 2008 DIGLLOYD INC
  #
  # constants for crd (create ram disk)
  # Copyright 2008 DIGLLOYD INC
  #
  # http://macperformanceguide.com/Mac-HowToUseARAMDisk.html
  # original name is crd; modify time 2010-01-19.12:19:59

  # minimum allowed size
  MIN_MB=32
  
  # maximum allowed size
  MAX_MB=60000
  
  # base name for ram disks
  VOLUME_NAME_BASE=RamDisk
  
  echo ""
  echo "Copyright 2010, DIGLLOYD INC. All Rights Reserved"
  echo "See our performance tools at http://macperformanceguide.com/Software-Main.html"
  echo ""
  echo "This script is designed for Mac OS X Snow Leopard 10.6.x only!."
  echo "Do not use it with OS X Leopard (10.5) or earlier."
  echo "..."
  echo ""
  
  PROG_NAME=$0
  EXAMPLE="${PROG_NAME}  4096 RamDisk1"
  
  if [ -n "$3" ]; then 
      echo Too many arguments.  Specify size in MB then volume name. Example:
      echo $EXAMPLE
      exit
  fi
  
  if [ -z "$2" ]; then
      echo Specify size in MB then volume name. Example:
      echo $EXAMPLE
      exit
  fi
  
  if [ -z "$1" ]; then
     echo Specify size in MB then volume name. Example:
     echo $EXAMPLE
     exit
  fi
  
  
  MB_SIZE=$1
  DISK_NAME=$2
  
  if [ ${MB_SIZE} -lt ${MIN_MB} ]; then
     echo RAM disk size minimum ${MIN_MB}MB, maximum ${MAX_MB}MB.
     echo $EXAMPLE
     exit
  fi
  
  if [ ${MB_SIZE} -gt ${MAX_MB} ]; then
     echo RAM disk size minimum ${MIN_MB}MB, maximum ${MAX_MB}MB.
     echo $EXAMPLE
     exit
  fi
  
  
  if [ -e /Volumes/$DISK_NAME ]; then
     echo Volume \"$DISK_NAME\" already exists, to unmount use: hdiutil detach /Volumes/$DISK_NAME
     exit
  fi
  
  
  BLOCKS=${MB_SIZE}
  let "BLOCKS *= 2048"
  
  echo Creating ${MB_SIZE} MB ram disk named ${DISK_NAME}
  echo hdid -nomount ram://$BLOCKS
  CREATED_RAMDISK=`hdid -nomount ram://$BLOCKS`
  
  echo New block device: ${CREATED_RAMDISK}
  #DISK_NAME=`basename ${CREATED_RAMDISK}`
  
  echo Creating volume named: ${DISK_NAME}
  newfs_hfs -v ${DISK_NAME} /dev/$CREATED_RAMDISK
  
  echo Mounting in /Volumes/${DISK_NAME}
  #mkdir /Volumes/${DISK_NAME}
  diskutil mount ${CREATED_RAMDISK}
  
  open -a Finder /Volumes/$DISK_NAME
  
  echo ""
  echo "RamDisk '${DISK_NAME}' created, ${MB_SIZE}MB"
}

createVolume() { (
  local name=$1
  local volume=/Volumes/$name
  echostep Creating and mounting $volume
  if [[ ! -e $volume ]] ; then
    createRamVolume 32 $name
    return 1
  else
    echo $volume already exists.
    return 0
  fi
) }

clearVolume() {
  local name=$1
  if [[ -z $name ]] ; then
    echo dangerous bug, exiting
    exit 2
  fi
  local volume=/Volumes/$name
  shopt -u nullglob
  files=$(echo $volume/*)
  if [[ "$files" != $volume/'*' ]] ; then
    echo "Removing $volume/*"
    rm -rf $volume/*
  fi
}

numberOfFiles() {
  local volume=$1
  echostep "Number of files on $volume: "
  find $volume -type f | lines
}

lines() {
  wc | awk '{ print $1}'
}

echodo() {
  eval "echo-command $@"
  eval "$@"
}

echo-command() {
  echo -n "[ "
  echo -n    $@
  echo        " ]"
}

echostep() {
  echo
  echo '========' "$@"
}

#===============================================================================

sourceName=LottaLinks ; source=/Volumes/$sourceName
destName=Copy         ;   dest=/Volumes/$destName

echostep "Test copying lots of hard links"
echo "
Make two minimal-sized ram disks, '$source' and '$dest'.
Populate $source with as many hard links sharing a single file as possible.
Copy $source to $dest.
See if it worked properly."

if ! createVolume $sourceName ; then
  echostep Populate the source volume
  filename=sleep
  rsync -a /bin/$filename $source
  makelinks $source $filename
fi

createVolume $destName

numberOfFiles $source

for x in \
     "/usr/bin/rsync -a --hard-links"
#     "/Local/Software/CCC/rsync -a --hard-links" \
#     "/usr/local/bin/rsync -a --hard-links"
#     ditto
do
  echostep "Clear volume $dest"
  clearVolume $destName

  echostep Copy using $x
  echodo $x $source/ $dest

  numberOfFiles $dest
done