bitbake: utils: add optional callback to edit_bblayers_conf()

Add a callback that lets you modify or remove items in addition to the
current scheme where you can only add or remove. This enables you to for
example replace a layer with a temporary copy (which is what we will use
this for first in OE's oe-selftest).

(Bitbake rev: 4f6ba26e8335f975038d90b9e1c1767160bd5272)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/utils.py

@@ -1290,7 +1290,7 @@ def edit_metadata_file(meta_file, variables, varfunc):
     return updated
 
 
-def edit_bblayers_conf(bblayers_conf, add, remove):
+def edit_bblayers_conf(bblayers_conf, add, remove, edit_cb=None):
     """Edit bblayers.conf, adding and/or removing layers
     Parameters:
         bblayers_conf: path to bblayers.conf file to edit
@@ -1298,6 +1298,8 @@ def edit_bblayers_conf(bblayers_conf, add, remove):
             list to add nothing
         remove: layer path (or list of layer paths) to remove; None or
             empty list to remove nothing
+        edit_cb: optional callback function that will be called after
+            processing adds/removes once per existing entry.
     Returns a tuple:
         notadded: list of layers specified to be added but weren't
             (because they were already in the list)
@@ -1361,6 +1363,17 @@ def edit_bblayers_conf(bblayers_conf, add, remove):
                     bblayers.append(addlayer)
             del addlayers[:]
 
+        if edit_cb:
+            newlist = []
+            for layer in bblayers:
+                res = edit_cb(layer, canonicalise_path(layer))
+                if res != layer:
+                    newlist.append(res)
+                    updated = True
+                else:
+                    newlist.append(layer)
+            bblayers = newlist
+
         if updated:
             if op == '+=' and not bblayers:
                 bblayers = None