bitbake: [parser] prepare to cache some .bbcclass and .inc files

Our parser is shit but instead to replace it now we will see
how long we can drive the wave by caching parsed files. This
will not go through the feeder again but we can just reevaluate
the StatementGroup.

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/lib/bb/parse/parse_py/BBHandler.py

@@ -78,6 +78,22 @@ def inherit(files, d):
             include(fn, file, d, "inherit")
             __inherit_cache = data.getVar('__inherit_cache', d) or []
 
+def get_statements(filename, absolsute_filename, base_name, file):
+    statements = ast.StatementGroup()
+
+    lineno = 0
+    while 1:
+        lineno = lineno + 1
+        s = file.readline()
+        if not s: break
+        s = s.rstrip()
+        feeder(lineno, s, filename, base_name, statements)
+    if __inpython__:
+        # add a blank line to close out any python definition
+        feeder(IN_PYTHON_EOF, "", filename, base_name, statements)
+
+    return statements
+
 def handle(fn, d, include):
     global __func_start_regexp__, __inherit_regexp__, __export_func_regexp__, __addtask_regexp__, __addhandler_regexp__, __infunc__, __body__, __residue__
     __body__ = []
@@ -113,17 +129,8 @@ def handle(fn, d, include):
     if include:
         bb.parse.mark_dependency(d, abs_fn)
 
-    statements = ast.StatementGroup()
-    lineno = 0
-    while 1:
-        lineno = lineno + 1
-        s = f.readline()
-        if not s: break
-        s = s.rstrip()
-        feeder(lineno, s, fn, base_name, statements)
-    if __inpython__:
-        # add a blank line to close out any python definition
-        feeder(IN_PYTHON_EOF, "", fn, base_name, statements)
+    # actual loading
+    statements = get_statements(fn, abs_fn, base_name, f)
 
     # DONE WITH PARSING... time to evaluate
     if ext != ".bbclass":