#! /bin/sh

# Script to tell whether a patch has been applied to a tree or not.
# Assume patch is in diff -u form, and applies in dir with -p1.

if [ $# != 2 ] || [ ! -d $1 ] || [ ! -f $2 ]
then
    echo Need directory and patch. >&2
    exit 1
fi

# Convert $2 to absolute.
case "$2"
in
    /*) PATCH="$2" ;;
    *) PATCH="`pwd`/$2" ;;
esac

[ -d tmp-isapplied ] && rm -rf tmp-isapplied

# Copy only files which are mentioned in patch.
# eg. +++ working-2.4.0-test11-5/net/ipv4/netfilter/ipt_MASQUERADE.c	Fri Dec  1 17:56:02 2000
mkdir tmp-isapplied
for f in `grep '^+++ ' $2 | cut -d/ -f2- | cut -d'	' -f1`
do
    mkdir -p `dirname tmp-isapplied/$f` 2>/dev/null
    cp $1/$f tmp-isapplied/$f 2>/dev/null
done

cd tmp-isapplied || (echo Can\'t change into tmp-isapplied >&2; exit 1)

patch -R -f -p1 < $PATCH > ../tmp-isapplied-result 2>&1

MISSING_FILES=`grep -c "No file to patch" < ../tmp-isapplied-result`
REJECTS=`grep -c "FAILED at" < ../tmp-isapplied-result`
HUNKS="`grep -c ^@@ $PATCH`"
NOTEMPTY_FILES=`grep -c "not empty after patch, as expected" < ../tmp-isapplied-result`

if [ "$MISSING_FILES" -ne 0 ]
then
    echo `basename $PATCH` NOT APPLIED \($MISSING_FILES missing files\)
    cd .. && rm -rf tmp-isapplied tmp-isapplied-result
    exit 1
elif [ "$NOTEMPTY_FILES" -ne 0 ]
then
    echo `basename $PATCH` ALREADY APPLIED \($REJECTS rejects out of $HUNKS hunks\).
    cd .. && rm -rf tmp-isapplied tmp-isapplied-result
    exit 0
elif [ `expr $REJECTS \* 2` -gt $HUNKS ]
then
    echo `basename $PATCH` NOT APPLIED \($REJECTS rejects out of $HUNKS hunks\)
    cd .. && rm -rf tmp-isapplied tmp-isapplied-result
    exit 1
else
    echo `basename $PATCH` ALREADY APPLIED \($REJECTS rejects out of $HUNKS hunks\).
    cd .. && rm -rf tmp-isapplied tmp-isapplied-result
    exit 0
fi