From a8c552d4770b50da1ed6248000392ac28fe17950 Mon Sep 17 00:00:00 2001
From: Dale Ogilvie <pnyli0002@sneakemail.com>
Date: Wed, 30 May 2007 11:48:18 +0100
Subject: Add support for creating xdeltas in makepkg.

Add xdelta option to makepkg.conf

Added xfer script to contrib.

Signed-off-by: Andrew Fyfe <andrew@neptune-one.net>
---
 contrib/wget-xdelta.sh | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 etc/makepkg.conf.in    |  2 +-
 scripts/makepkg.in     | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+), 1 deletion(-)
 create mode 100755 contrib/wget-xdelta.sh

diff --git a/contrib/wget-xdelta.sh b/contrib/wget-xdelta.sh
new file mode 100755
index 00000000..d99dd3cc
--- /dev/null
+++ b/contrib/wget-xdelta.sh
@@ -0,0 +1,47 @@
+#!/bin/bash
+o=$(basename $1)
+u=$2
+CARCH="i686" # Hmmm where to get this from? /etc/makepkg.conf?
+cached_file=""
+# Only check for pkg.tar.gz files in the cache, we download db.tar.gz as well
+if [[ "$o" =~ "pkg.tar.gz" ]] # if $o contains pkg.tar.gz
+then
+  pkgname=${o%-*-[0-9]-${CARCH}.pkg.tar.gz.part}   # Parse out the package name
+  newend=${o##$pkgname-}                  # Parse out everything following pkgname
+  new_version=${newend%-${CARCH}.pkg.tar.gz.part}  # Strip off .pkg.tar.gz.part leaving version
+  url=${u%/*}
+  for cached_file in $(ls -r /var/cache/pacman/pkg/${pkgname}-*-${CARCH}.pkg.tar.gz 2>/dev/null); do
+    # just take the first one, by name. I suppose we could take the latest by date...
+    oldend=${cached_file##*/$pkgname-}
+    old_version=${oldend%-${CARCH}.pkg.tar.gz}
+    if [ "$old_version" = "$new_version" ]; then
+      # We already have the new version in the cache! Just continue the download.
+      cached_file=""
+    fi
+    break
+  done
+fi
+if [ "$cached_file" != "" ]; then
+  # Great, we have a cached file, now calculate a patch name from it
+  delta_name=$pkgname-${old_version}_to_${new_version}-${CARCH}.delta
+  # try to download the delta
+  if wget --passive-ftp -c $url/$delta_name; then
+    # Now apply the delta to the cached file to produce the new file
+    echo Applying delta...
+    if xdelta patch $delta_name $cached_file $o; then
+      # Remove the delta now that we are finished with it
+      rm $delta_name
+    else
+      # Hmmm. xdelta failed for some reason
+      rm $delta_name
+      # just download the file
+      wget --passive-ftp -c -O $o $u
+    fi
+  else
+    # just download the file
+    wget --passive-ftp -c -O $o $u
+  fi 
+else
+  # just download the file
+  wget --passive-ftp -c -O $o $u
+fi
diff --git a/etc/makepkg.conf.in b/etc/makepkg.conf.in
index 2fc796e1..b68b937e 100644
--- a/etc/makepkg.conf.in
+++ b/etc/makepkg.conf.in
@@ -46,7 +46,7 @@ CXXFLAGS="-@ARCHSWITCH@=@CARCHFLAGS@ -mtune=generic -O2 -pipe"
 #-- color:    Colorize output messages
 #-- ccache:   Use ccache to cache compilation
 #
-BUILDENV=(fakeroot !distcc color !ccache)
+BUILDENV=(fakeroot !distcc color !ccache !xdelta)
 #
 #-- If using DistCC, your MAKEFLAGS will also need modification. In addition,
 #-- specify a space-delimited list of hosts running in the DistCC cluster.
diff --git a/scripts/makepkg.in b/scripts/makepkg.in
index 00e7b443..8c573461 100644
--- a/scripts/makepkg.in
+++ b/scripts/makepkg.in
@@ -594,6 +594,53 @@ create_package() {
 		error "$(gettext "Failed to create package file.")"
 		exit 1 # TODO: error code
 	fi
+
+	create_xdelta "$pkg_file"
+}
+
+create_xdelta() {
+	if [ "$(check_buildenv xdelta)" != "y" ]; then
+		return
+	fi
+
+	# Check to see if we have any old versions to create deltas with
+	local pkg_file=$1
+	local base_file=""
+	local delta_file=""
+	local cache_dir="/var/cache/pacman/pkg"
+	local latest_version=""
+	local old_versions=( $(ls ${cache_dir}/${pkgname}-*-${CARCH}.${PKGEXT} 2>/dev/null; ls ${PKGDEST}/${pkgname}-*-${CARCH}.${PKGEXT} 2>/dev/null) )
+
+	local old_file dirname filename namend old_version
+	for old_file in "${old_versions[@]}"; do
+		dirname=$(dirname $old_file)
+		filename=$(basename $old_file)
+		namend=${filename#"$pkgname-"}
+		old_version=${namend%-"${CARCH}.${PKGEXT}"}
+
+		# old_version may include the target package, only use the old versions
+		if [ "$old_version" != "$pkgver-$pkgrel" ] && [[ "$old_version" > "$latest_version" ]]; then
+			latest_version=$old_version
+			base_file=$old_file
+			delta_file=$PKGDEST/$pkgname-${old_version}_to_$pkgver-$pkgrel-${CARCH}.delta
+		fi
+	done
+
+	if [ "$delta_file" != "" ]; then
+		msg "Making delta from version $latest_version"
+		# xdelta will decompress base_file & pkg_file into TMP_DIR (or /tmp if TMP_DIR is unset)
+		# then perform the delta on the resulting tars
+		xdelta delta $base_file $pkg_file $delta_file
+		# Generate the final gz using xdelta for compression. xdelta will be our common
+		# denominator compression utility between the packager and the users
+		#
+		# makepkg and pacman must use the same compression algorithm or the delta generated
+		# package may not match, producing md5 checksum errors.
+		#
+		xdelta patch $delta_file $base_file $pkg_file
+	else
+		msg "No previous version found, skipping xdelta"
+	fi
 }
 
 create_srcpackage() {
-- 
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