1 files changed, 47 insertions, 0 deletions
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