bitbake: Add codeparser for parsing shell and python functions

This commit is derived from Chris Larson's checksum work, turned into a
standalone piece of code for parsing python and shell functions.

The deindent code has been replaced with code to work around indentation
for speed. The original NodeVisitor in the ast was replaced with a faster
class walk call.

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

bitbake/lib/bb/data_smart.py

@@ -46,7 +46,7 @@ class VariableParse:
         self.value = val
 
         self.references = set()
-        self.funcrefs = set()
+        self.execs = set()
 
     def var_sub(self, match):
             key = match.group()[2:-1]
@@ -64,10 +64,10 @@ class VariableParse:
             code = match.group()[3:-1]
             codeobj = compile(code.strip(), self.varname or "<expansion>", "eval")
 
-            parser = bb.rptest.PythonParser()
+            parser = bb.codeparser.PythonParser()
             parser.parse_python(code)
             self.references |= parser.references
-            self.funcrefs |= parser.execs
+            self.execs |= parser.execs
 
             value = utils.better_eval(codeobj, {"d": self.d})
             return str(value)