kiss: alternatives: initial working solution

kiss

@@ -822,14 +822,47 @@ pkg_conflicts() {
 }
 
 pkg_swap() {
+    # Swap between package alternatives.
+
     # Check to see if the package is installed. This
     # will exit with an error if it is not.
     pkg_list "$1" >/dev/null
 
     alt=$(printf %s "$1$2" | sed 's|/|>|g')
+    cd "$sys_db/../choices"
 
-    [ -f "$sys_db/../choices/$alt" ] ||
+    [ -f "$alt" ] || [ -h "$alt" ] ||
         die "Alternative '$1 $2' doesn't exist"
+
+    if [ -f "$2" ]; then
+        # Figure out which package owns the file we are going to
+        # swap for another package's.
+        #
+        # Print the full path to the manifest file which contains
+        # the match to our search.
+        pkg_owns=$(set +f; "$grep" -lFx "$2" "$sys_db/"*/manifest) ||:
+
+        # Extract the package name from the path above.
+        pkg_owns=${pkg_owns%/*}
+        pkg_owns=${pkg_owns##*/}
+
+        [ "$pkg_owns" ] ||
+            die "File '$2' exists on filesystem but isn't owned"
+
+        log "Swapping '$2' from '$pkg_owns' to '$1'"
+
+        # Convert the current owner to an alternative and rewrite
+        # its manifest file to reflect this.
+        dosu mv  -f "'$2'" "'$pkg_owns>${alt#*>}'"
+        dosu sed -i "'s|$2|$PWD/$pkg_owns>${alt#*>}|'" \
+            "'../installed/$pkg_owns/manifest'"
+    fi
+
+    # Convert the desired alternative to a real file and rewrite
+    # the manifest file to reflect this. The reverse of above.
+    dosu mv  -f "'$alt'" "'$2'"
+    dosu sed -i "'s|$PWD/$alt|$2|'" \
+        "'../installed/$1/manifest'"
 }
 
 pkg_remove() {
@@ -1195,7 +1228,7 @@ args() {
                 # Go over each alternative and format the file
                 # name for listing. (pkg_name>usr>bin>ls)
                 for pkg in *; do
-                    [ -f "$pkg" ] &&
+                    [ "$pkg" = '*' ] ||
                         printf '%s\n' "$pkg" | sed 's|>| /|;s|>|/|g'
                 done
             fi