#!/bin/bash

# Grab default values for $CFLAGS and such.

export LANG=c
export LC_ALL=C
set -o pipefail
source ./configure

[ -z "$KCONFIG_CONFIG" ] && KCONFIG_CONFIG=".config"

# Since each cc invocation is short, launch half again as many processes
# as we have processors so they don't exit faster than we can start them.
[ -z "$CPUS" ] &&
  CPUS=$((($(echo /sys/devices/system/cpu/cpu[0-9]* | wc -w)*3)/2))

# Respond to V= by echoing command lines as well as running them
DOTPROG=
do_loudly()
{
  [ ! -z "$V" ] && echo "$@" || echo -n "$DOTPROG"
  "$@"
}

# Is anything under directory $2 newer than file $1
isnewer()
{
 [ ! -z "$(find "$2" -newer "$1" 2>/dev/null || echo yes)" ]
}

echo "Generate headers from toys/*/*.c..."

mkdir -p generated

if isnewer generated/Config.in toys
then
  echo "Extract configuration information from toys/*.c files..."
  scripts/genconfig.sh
fi

# Create a list of all the commands toybox can provide. Note that the first
# entry is out of order on purpose (the toybox multiplexer command must be the
# first element of the array). The rest must be sorted in alphabetical order
# for fast binary search.

if isnewer generated/newtoys.h toys
then
  echo -n "generated/newtoys.h "

  echo "USE_TOYBOX(NEWTOY(toybox, NULL, TOYFLAG_STAYROOT))" > generated/newtoys.h
  sed -n -e 's/^USE_[A-Z0-9_]*(/&/p' toys/*/*.c \
	| sed 's/\(.*TOY(\)\([^,]*\),\(.*\)/\2 \1\2,\3/' | sort -s -k 1,1 \
	| sed 's/[^ ]* //'  >> generated/newtoys.h || exit 1
fi

[ ! -z "$V" ] && echo "Which C files to build..."

# Extract a list of toys/*/*.c files to compile from the data in $KCONFIG_CONFIG
# (First command names, then filenames with relevant {NEW,OLD}TOY() macro.)

TOYFILES="$(sed -n 's/^CONFIG_\([^=]*\)=.*/\1/p' "$KCONFIG_CONFIG" | xargs | tr ' [A-Z]' '|[a-z]')"
TOYFILES="$(egrep -l "TOY[(]($TOYFILES)[ ,]" toys/*/*.c)"
BUILD="$(echo ${CROSS_COMPILE}${CC} $CFLAGS -I . $OPTIMIZE)"
FILES="$(echo lib/*.c main.c $TOYFILES)"

genbuildsh()
{
  # Write a canned build line for use on crippled build machines.

  echo "#!/bin/sh"
  echo
  echo "BUILD=\"$BUILD\""
  echo
  echo "FILES=\"$FILES\""
  echo
  echo "LINK=\"$LINK\""
  echo
  echo
  echo '$BUILD $FILES $LINK'
}

if ! cmp -s <(genbuildsh | head -n 3) \
          <(head -n 3 generated/build.sh 2>/dev/null)
then
  echo -n "Library probe"

  # We trust --as-needed to remove each library if we don't use any symbols
  # out of it, this loop is because the compiler has no way to ignore a library
  # that doesn't exist, so we have to detect and skip nonexistent libraries
  # for it.

  > generated/optlibs.dat
  for i in util crypt m resolv selinux
  do
    echo "int main(int argc, char *argv[]) {return 0;}" | \
    ${CROSS_COMPILE}${CC} $CFLAGS -xc - -o /dev/null -Wl,--as-needed -l$i > /dev/null 2>/dev/null &&
    echo -l$i >> generated/optlibs.dat
    echo -n .
  done
  echo
fi

# LINK needs optlibs.dat, above

LINK="$(echo $LDOPTIMIZE $LDFLAGS -o toybox_unstripped -Wl,--as-needed $(cat generated/optlibs.dat))"
genbuildsh > generated/build.sh && chmod +x generated/build.sh || exit 1

echo "Make generated/config.h from $KCONFIG_CONFIG."

# This long and roundabout sed invocation is to make old versions of sed happy.
# New ones have '\n' so can replace one line with two without all the branches
# and tedious mucking about with hold space.

sed -n \
  -e 's/^# CONFIG_\(.*\) is not set.*/\1/' \
  -e 't notset' \
  -e 's/^CONFIG_\(.*\)=y.*/\1/' \
  -e 't isset' \
  -e 's/^CONFIG_\([^=]*\)=\(.*\)/#define CFG_\1 \2/p' \
  -e 'd' \
  -e ':notset' \
  -e 'h' \
  -e 's/.*/#define CFG_& 0/p' \
  -e 'g' \
  -e 's/.*/#define USE_&(...)/p' \
  -e 'd' \
  -e ':isset' \
  -e 'h' \
  -e 's/.*/#define CFG_& 1/p' \
  -e 'g' \
  -e 's/.*/#define USE_&(...) __VA_ARGS__/p' \
  $KCONFIG_CONFIG > generated/config.h || exit 1

if [ generated/mkflags -ot scripts/mkflags.c ]
then
  do_loudly $HOSTCC scripts/mkflags.c -o generated/mkflags || exit 1
fi

echo -n "generated/flags.h "

# Process config.h and newtoys.h to generate FLAG_x macros. Note we must
# always #define the relevant macro, even when it's disabled, because we
# allow multiple NEWTOY() in the same C file. (When disabled the FLAG is 0,
# so flags&0 becomes a constant 0 allowing dead code elimination.)

# Parse files through C preprocessor twice, once to get flags for current
# .config and once to get flags for allyesconfig
for I in A B
do
  (
  # define macros and select header files with option string data

  echo "#define NEWTOY(aa,bb,cc) aa $I bb"
  echo '#define OLDTOY(...)'
  if [ "$I" == A ]
  then
    cat generated/config.h
  else
    sed '/USE_.*([^)]*)$/s/$/ __VA_ARGS__/' generated/config.h
  fi
  cat generated/newtoys.h

  # Run result through preprocessor, glue together " " gaps leftover from USE
  # macros, delete comment lines, print any line with a quoted optstring,
  # turn any non-quoted opstring (NULL or 0) into " " (because fscanf can't
  # handle "" with nothing in it, and mkflags uses that).

  ) | ${CROSS_COMPILE}${CC} -E - | \
    sed -n -e 's/" *"//g;/^#/d;t clear;:clear;s/"/"/p;t;s/\( [AB] \).*/\1 " "/p'

# Sort resulting line pairs and glue them together into triplets of
#   command "flags" "allflags"
# to feed into mkflags C program that outputs actual flag macros
# If no pair (because command's disabled in config), use " " for flags
# so allflags can define the appropriate zero macros.

done | sort -s | sed -n 's/ A / /;t pair;h;s/\([^ ]*\).*/\1 " "/;x;b single;:pair;h;n;:single;s/[^ ]* B //;H;g;s/\n/ /;p' |\
generated/mkflags > generated/flags.h || exit 1

# Extract global structure definitions and flag definitions from toys/*/*.c

function getglobals()
{
  for i in toys/*/*.c
  do
    NAME="$(echo $i | sed 's@.*/\(.*\)\.c@\1@')"
    DATA="$(sed -n -e '/^GLOBALS(/,/^)/b got;b;:got' \
            -e 's/^GLOBALS(/struct '"$NAME"'_data {/' \
            -e 's/^)/};/' -e 'p' $i)"

    [ ! -z "$DATA" ] && echo -e "// $i\n\n$DATA\n"
  done
}

if isnewer generated/globals.h toys
then
  echo -n "generated/globals.h "
  GLOBSTRUCT="$(getglobals)"
  (
    echo "$GLOBSTRUCT"
    echo
    echo "extern union global_union {"
    echo "$GLOBSTRUCT" | \
      sed -n 's/struct \(.*\)_data {/	struct \1_data \1;/p'
    echo "} this;"
  ) > generated/globals.h
fi

echo "generated/help.h"
if [ generated/config2help -ot scripts/config2help.c ]
then
  do_loudly $HOSTCC scripts/config2help.c -I . lib/xwrap.c lib/llist.c \
    lib/lib.c lib/portability.c -o generated/config2help || exit 1
fi
generated/config2help Config.in $KCONFIG_CONFIG > generated/help.h || exit 1

[ ! -z "$NOBUILD" ] && exit 0

echo -n "Compile toybox"
[ ! -z "$V" ] && echo
DOTPROG=.

# This is a parallel version of: do_loudly $BUILD $FILES $LINK || exit 1

X="$(ls -1t generated/obj/* 2>/dev/null | tail -n 1)"
if [ ! -e "$X" ] || [ ! -z "$(find toys -name "*.h" -newer "$X")" ]
then
  rm -rf generated/obj && mkdir -p generated/obj || exit 1
else
  rm -f generated/obj/{main,lib_help}.o || exit 1
fi
PENDING=
LFILES=
DONE=0
for i in $FILES
do
  # build each generated/obj/*.o file in parallel

  X=${i/lib\//lib_}
  X=${X##*/}
  OUT="generated/obj/${X%%.c}.o"
  LFILES="$LFILES $OUT"
  [ "$OUT" -nt "$i" ] && continue
  do_loudly $BUILD -c $i -o $OUT &

  # ratelimit to $CPUS many parallel jobs, detecting errors

  while true
  do
    PENDING="$(echo $PENDING $(jobs -rp) | tr ' ' '\n' | sort -u)"
    [ $(echo -n "$PENDING" | wc -l) -lt "$CPUS" ] && break;

    wait $(echo "$PENDING" | head -n 1)
    DONE=$(($DONE+$?))
    PENDING="$(echo "$PENDING" | tail -n +2)"
  done
  [ $DONE -ne 0 ] && break
done

# wait for all background jobs, detecting errors

for i in $PENDING
do
  wait $i
  DONE=$(($DONE+$?))
done

[ $DONE -ne 0 ] && exit 1

do_loudly $BUILD $LFILES $LINK || exit 1
if ! do_loudly ${CROSS_COMPILE}strip toybox_unstripped -o toybox
then
  echo "strip failed, using unstripped" && cp toybox_unstripped toybox ||
  exit 1
fi
# gcc 4.4's strip command is buggy, and doesn't set the executable bit on
# its output the way SUSv4 suggests it do so.
do_loudly chmod +x toybox || exit 1
echo
