1 files changed, 24 insertions, 2 deletions

diff --git a/bin/build-snapshot b/bin/build-snapshot
index 43c6293..5633abd 100755
--- a/bin/build-snapshot
+++ b/bin/build-snapshot
@@ -59,6 +59,29 @@ create_snapshot()
         cd "$OLDPWD"
 }
 
+rm_old_snapshots()
+{
+        snapshot_dir=$1
+        keep_days=$2
+        link_targets=$(find "$snapshot_dir" -type l -exec readlink '{}' ';')
+
+        find "$snapshot_dir" -type f -mtime "+$((keep_days - 1))" -print \
+            | while read file
+        do
+                referenced=0
+
+                for link_target in $link_targets
+                do
+                        if [ "$link_target" = "$file" ]
+                        then
+                                referenced=1
+                                break
+                        fi
+                done
+                test $referenced -eq 1 || rm -f "$file"
+        done
+}
+
 if [ $# -eq 1 ] && [ "x$1" = 'x-h' -o "x$1" = 'x--help' ]
 then
         echo "Usage: $myself [branch ...]"
@@ -82,7 +105,6 @@ do
 done
 
 cd "$OLDPWD"
-find "$snapshot_dir" -type f -mtime "+$((keep_days - 1))" -exec rm -f '{}' '+'
-find "$snapshot_dir" -type l '!' -exec test -e '{}' ';' -exec rm -f '{}' '+'
+rm_old_snapshots "$snapshot_dir" "$keep_days"
 trap - EXIT
 rm -rf "$temp_dir"