#!/bin/bash


# Stream producers
#
# These produce a stream of escaped new-line separated items
#

# Stream the given arguments
#
VGL_sourceS() {
  ( printf '%q\n' "$@" ) || (( $? == 141 ))
}


# Stream the results of the given command
#
VGL_systemS() {
  declare -a command=("$@")
  ( eval $(printf '%q ' "${command[@]}") ) || (( $? == 141 ))
}

# Stream the results of find (correctly escapes all filenames)
#
VGL_findS() {
  declare -a options=("$@") file
  VGL_systemS find "${options[@]}" -print0 |
    while read -d '' -r file; do
      VGL_sourceS "$file"
    done
}

# Stream the closure of the list libraries from an elf file
#
VGL_elfLibsS() {
  declare file=$1 line
  VGL_systemS ldd "$file" |
    while read line; do
      line=${line#$'\t'}
      case "$line" in
        *' => not found')
          line=${line% => not found}
          ;;
        *' => '*' ('*')')
          line=${line#* => }
          line=${line% (*)}
          ;;
        *' ('*')')
          line=${line% (*)}
          ;;
      esac
      VGL_sourceS "$line"
    done
}



# Stream transformers
#
# Take in a set of options and transform a stream of new-line separated items
#

# Group all items onto a single line separated by given deliminator (or space)
#
VGL_joinS() {
  declare deliminator=${1- } next
  if read next; then
    printf '%q' "$next"
    while read next; do
      printf '%s%q' "$deliminator" "$next"
    done
    printf '\n'
  fi
}

# Remove all items for which the given command returns false
#
VGL_filterS() {
  declare command=("$@")
  while read next; do
    if eval $(printf '%q ' "${command[@]}" "$next"); then
      VGL_sourceS "$next"
    fi
  done
}



# Stream consumers
#
# These consume a stream of escaped new-line separated items
#
VGL_anyS() {
  declare command=("$@")
  while read next; do
    if eval $(printf '%q ' "${command[@]}" "$next"); then
      return 0
    fi
  done
  return 1
}


# Tests for the filter transformer
#

# Check for an elf file (binary or library)
#
VGL_isElfBin() {
  declare file=$1
  case "$(file -b -N --mime-type "$file")" in
    application/x-executable | application/x-pie-executable)
      return 0 ;;
    *)
      return 1 ;;
  esac
}

# Check for libGL
#
VGL_isLibGL() {
  declare file=$1
  case "$file" in
    libGL.so* | */libGL.so*)
      return 0 ;;
    *)
      return 1 ;;
  esac
}



# Setup hook
#

# Find all executables that depend on libGL and add a libvglfaker.so dependency
#
VGL_autoAddVGL() {
  echo "Inserting VirtualGL into OpenGL executables in $prefix..." >&2

  for output in $outputs; do
    VGL_findS "${!output}" -type f | VGL_filterS VGL_isElfBin | {
      declare file
      while read file; do
        VGL_elfLibsS "$file" |
          if VGL_anyS VGL_isLibGL; then
            VGL_sourceS "$file"
          fi
      done
    } | {
      declare file
      while read file; do
        printf 'patchelf --add-needed @virtualglLib@/lib/libvglfaker.so %q\n' "$file" >&2
        patchelf --add-needed @virtualglLib@/lib/libvglfaker.so "$file"
      done
    }
  done
}

postFixupHooks+=(VGL_autoAddVGL)