[gentoo-dev] rewritten epatch

[Mike Frysinger]

for various reasons/limitations/bugs/whatever, i rewrote epatch.  seems to
work for me, but in case someone wants to check before i release:
epatch() {
	_epatch_draw_line() {
		# create a line of same length as input string
		[[ -z $1 ]] && set "$(printf "%65s" '')"
		echo "${1//?/=}"
	}

	unset P4CONFIG P4PORT P4USER # keep perforce at bay #56402

	# Let the rest of the code process one user arg at a time --
	# each arg may expand into multiple patches, and each arg may
	# need to start off with the default global EPATCH_xxx values
	if [[ $# -gt 1 ]] ; then
		local m
		for m in "$@" ; do
			epatch "${m}"
		done
		return 0
	fi

	local SINGLE_PATCH="no"
	# no args means process ${EPATCH_SOURCE}
	[[ $# -eq 0 ]] && set -- "${EPATCH_SOURCE}"

	if [[ -f $1 ]] ; then
		SINGLE_PATCH="yes"
		set -- "$1"
		# Use the suffix from the single patch (localize it); the code
		# below will find the suffix for us
		local EPATCH_SUFFIX=$1

	elif [[ -d $1 ]] ; then
		# Some people like to make dirs of patches w/out suffixes (vim)
		set -- "$1"/*${EPATCH_SUFFIX:+."${EPATCH_SUFFIX}"}

	else
		# sanity check ... if it isn't a dir or file, wtf man ?
		[[ $# -ne 0 ]] && EPATCH_SOURCE=$1
		echo
		eerror "Cannot find \$EPATCH_SOURCE!  Value for \$EPATCH_SOURCE is:"
		eerror
		eerror "  ${EPATCH_SOURCE}"
		eerror "  ( ${EPATCH_SOURCE##*/} )"
		echo
		die "Cannot find \$EPATCH_SOURCE!"
	fi

	local PIPE_CMD
	case ${EPATCH_SUFFIX##*\.} in
		xz)      PIPE_CMD="xz -dc"    ;;
		lzma)    PIPE_CMD="lzma -dc"  ;;
		bz2)     PIPE_CMD="bzip2 -dc" ;;
		gz|Z|z)  PIPE_CMD="gzip -dc"  ;;
		ZIP|zip) PIPE_CMD="unzip -p"  ;;
		*)       ;;
	esac

	[[ ${SINGLE_PATCH} == "no" ]] && einfo "${EPATCH_MULTI_MSG}"

	local x
	for x in "$@" ; do
		# If the patch dir given contains subdirs, or our EPATCH_SUFFIX
		# didn't match anything, ignore continue on
		[[ ! -f ${x} ]] && continue

		local patchname=${x##*/}

		# Apply single patches, or forced sets of patches, or
		# patches with ARCH dependant names.
		#	???_arch_foo.patch
		# Else, skip this input altogether
		local a=${patchname#*_} # strip the ???_
		a=${a%%_*}              # strip the _foo.patch
		if ! [[ ${SINGLE_PATCH} == "yes" || \
		        ${EPATCH_FORCE} == "yes" || \
		        ${a} == all     || \
		        ${a} == ${ARCH} ]]
		then
			continue
		fi

		# Let people filter things dynamically
		if [[ -n ${EPATCH_EXCLUDE} ]] ; then
			# let people use globs in the exclude
			eshopts_push -o noglob

			local ex
			for ex in ${EPATCH_EXCLUDE} ; do
				if [[ ${patchname} == ${ex} ]] ; then
					eshopts_pop
					continue
				fi
			done
			eshopts_pop
		fi

		if [[ ${SINGLE_PATCH} == "yes" ]] ; then
			if [[ -n ${EPATCH_SINGLE_MSG} ]] ; then
				einfo "${EPATCH_SINGLE_MSG}"
			else
				einfo "Applying ${patchname} ..."
			fi
		else
			einfo "  ${patchname} ..."
		fi

		# most of the time, there will only be one run per unique name,
		# but if there are more, make sure we get unique log filenames
		local STDERR_TARGET="${T}/${patchname}.out"
		if [[ -e ${STDERR_TARGET} ]] ; then
			STDERR_TARGET="${T}/${patchname}-$$.out"
		fi

		printf "***** %s *****\n\n" "${patchname}" > "${STDERR_TARGET}"

		# Decompress the patch if need be
		local count=0
		local PATCH_TARGET
		if [[ -n ${PIPE_CMD} ]] ; then
			PATCH_TARGET="${T}/$$.patch"
			echo "PIPE_COMMAND:  ${PIPE_CMD} ${x} > ${PATCH_TARGET}" >> "${STDERR_TARGET}"

			if ! (${PIPE_CMD} "${x}" > "${PATCH_TARGET}") >> "${STDERR_TARGET}" 2>&1 ; then
				echo
				eerror "Could not extract patch!"
				#die "Could not extract patch!"
				count=5
				break
			fi
		else
			PATCH_TARGET=${x}
		fi

		# Check for absolute paths in patches.  If sandbox is disabled,
		# people could (accidently) patch files in the root filesystem.
		# Or trigger other unpleasantries #237667.  So disallow -p0 on
		# such patches.
		local abs_paths=$(egrep -n '^[-+]{3} /' "${PATCH_TARGET}" | awk '$2 != "/dev/null" { print }')
		if [[ -n ${abs_paths} ]] ; then
			count=1
			printf "NOTE: skipping -p0 due to absolute paths in patch:\n%s\n" "${abs_paths}" >> "${STDERR_TARGET}"
		fi

		# Dynamically detect the correct -p# ... i'm lazy, so shoot me :/
		while [[ ${count} -lt 5 ]] ; do
			# Generate some useful debug info ...
			(
			_epatch_draw_line "***** ${patchname} *****"
			echo
			echo "PATCH COMMAND:  patch -p${count} ${EPATCH_OPTS} < '${PATCH_TARGET}'"
			echo
			_epatch_draw_line "***** ${patchname} *****"
			) >> "${STDERR_TARGET}"

			if (patch -p${count} ${EPATCH_OPTS} --dry-run -f < "${PATCH_TARGET}") >> "${STDERR_TARGET}" 2>&1 ; 
then
				(
				_epatch_draw_line "***** ${patchname} *****"
				echo
				echo "ACTUALLY APPLYING ${patchname} ..."
				echo
				_epatch_draw_line "***** ${patchname} *****"
				patch -p${count} ${EPATCH_OPTS} < "${PATCH_TARGET}" 2>&1
				) >> "${STDERR_TARGET}"

				if [ $? -ne 0 ] ; then
					echo
					eerror "A dry-run of patch command succeeded, but actually"
					eerror "applying the patch failed!"
					#die "Real world sux compared to the dreamworld!"
					count=5
				fi
				break
			fi

			: $(( count++ ))
		done

		# if we had to decompress the patch, delete the temp one
		if [[ -n ${PIPE_CMD} ]] ; then
			rm -f "${PATCH_TARGET}"
		fi

		if [[ ${count} -ge 5 ]] ; then
			echo
			eerror "Failed Patch: ${patchname} !"
			eerror " ( ${PATCH_TARGET} )"
			eerror
			eerror "Include in your bugreport the contents of:"
			eerror
			eerror "  ${STDERR_TARGET}"
			echo
			die "Failed Patch: ${patchname}!"
		fi

		# if everything worked, delete the patch log
		rm -f "${STDERR_TARGET}"
		eend 0
	done

	[[ ${SINGLE_PATCH} == "no" ]] && einfo "Done with patching"
	: # everything worked
}
-mike