common/hooks: add support for do-<phase> hooks as suggested by Gottox.

- New hooks for do-fetch and do-extract moved from xbps-src.
- Renamed some hooks to have XX as prefix.

common/hooks/do-fetch/00-distfiles.sh

@@ -0,0 +1,102 @@
+# This hook downloads the distfiles specified in a template by
+# the $distfiles variable and then verifies its sha256 checksum comparing
+# its value with the one stored in the $checksum variable.
+
+verify_sha256_cksum() {
+	local file="$1" origsum="$2" distfile="$3"
+
+	[ -z "$file" -o -z "$cksum" ] && return 1
+
+	msg_normal "$pkgver: verifying checksum for distfile '$file'... "
+	filesum=$(${XBPS_DIGEST_CMD} $distfile)
+	if [ "$origsum" != "$filesum" ]; then
+		echo
+		msg_red "SHA256 mismatch for '$file:'\n$filesum\n"
+		return 1
+	else
+		msg_normal_append "OK.\n"
+	fi
+}
+
+hook() {
+	local srcdir="$XBPS_SRCDISTDIR/$pkgname-$version"
+
+	if [ ! -d "$srcdir" ]; then
+		mkdir -p -m775 "$srcdir"
+		chgrp $(id -g) "$srcdir"
+	fi
+
+	cd $srcdir || msg_error "$pkgver: cannot change dir to $srcdir!\n"
+
+	for f in ${distfiles}; do
+		curfile=$(basename $f)
+		distfile="$srcdir/$curfile"
+		while true; do
+			flock -w 1 ${distfile}.part true
+			if [ $? -eq 0 ]; then
+				break
+			fi
+			msg_warn "$pkgver: ${distfile} is being already downloaded, waiting for 1s ...\n"
+		done
+		if [ -f "$distfile" ]; then
+			flock -n ${distfile}.part rm -f ${distfile}.part
+			for i in ${checksum}; do
+				if [ $dfcount -eq $ckcount -a -n "$i" ]; then
+					cksum=$i
+					found=yes
+					break
+				fi
+				ckcount=$(($ckcount + 1))
+			done
+			if [ -z $found ]; then
+				msg_error "$pkgver: cannot find checksum for $curfile.\n"
+			fi
+
+			verify_sha256_cksum $curfile $cksum $distfile
+			rval=$?
+			unset cksum found
+			ckcount=0
+			dfcount=$(($dfcount + 1))
+			continue
+		fi
+
+		msg_normal "$pkgver: fetching distfile '$curfile'...\n"
+
+		if [ -n "$distfiles" ]; then
+			localurl="$f"
+		else
+			localurl="$url/$curfile"
+		fi
+
+		flock ${distfile}.part $XBPS_FETCH_CMD $localurl
+		if [ $? -ne 0 ]; then
+			unset localurl
+			if [ ! -f $distfile ]; then
+				msg_error "$pkgver: couldn't fetch $curfile.\n"
+			else
+				msg_error "$pkgver: there was an error fetching $curfile.\n"
+			fi
+		else
+			unset localurl
+			#
+			# XXX duplicate code.
+			#
+			for i in ${checksum}; do
+				if [ $dfcount -eq $ckcount -a -n "$i" ]; then
+					cksum=$i
+					found=yes
+					break
+				fi
+				ckcount=$(($ckcount + 1))
+			done
+			if [ -z $found ]; then
+				msg_error "$pkgver: cannot find checksum for $curfile.\n"
+			fi
+			verify_sha256_cksum $curfile $cksum $distfile
+			rval=$?
+			unset cksum found
+			ckcount=0
+		fi
+		dfcount=$(($dfcount + 1))
+	done
+}