bitbake: codeparser: Allow code visitor expressions to be declared in metadata

Allow the metadata to define code visitor expressions which mean that
custom dependencies can be handled in function libraries.

An example is the qa.handle_error function in OE which can set something
like:

"""
def handle_error_visitorcode(name, args):
    execs = set()
    contains = {}
    warn = None
    if isinstance(args[0], ast.Constant) and isinstance(args[0].value, str):
        for i in ["ERROR_QA", "WARN_QA"]:
            if i not in contains:
                contains[i] = set()
        contains[i].add(args[0].value)
    else:
        warn = args[0]
        execs.add(name)
    return contains, execs, warn

handle_error.visitorcode = handle_error_visitorcode
"""

Meaning that it can have contains optimisations on ERROR and WARN_QA
instead of hard dependencies.

One drawback to this solution is the parsing order. Functions with
visitorcode need to be defined before anything else references them
or the visitor code will not function for the earlier references.

(Bitbake rev: 5bd0c65c217394cde4c8e382eba6cf7f4b909c97)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/cache.py

@@ -28,7 +28,7 @@ import shutil
 
 logger = logging.getLogger("BitBake.Cache")
 
-__cache_version__ = "155"
+__cache_version__ = "156"
 
 def getCacheFile(path, filename, mc, data_hash):
     mcspec = ''

bitbake/lib/bb/codeparser.py

@@ -87,14 +87,17 @@ def add_module_functions(fn, functions, namespace):
             if e in functions:
                 execs.remove(e)
                 execs.add(namespace + "." + e)
-        modulecode_deps[name] = [parser.references.copy(), execs, parser.var_execs.copy(), parser.contains.copy(), parser.extra]
+        visitorcode = None
+        if hasattr(functions[f], 'visitorcode'):
+            visitorcode = getattr(functions[f], "visitorcode")
+        modulecode_deps[name] = [parser.references.copy(), execs, parser.var_execs.copy(), parser.contains.copy(), parser.extra, visitorcode]
         #bb.warn("%s: %s\nRefs:%s Execs: %s %s %s" % (name, fn, parser.references, parser.execs, parser.var_execs, parser.contains))
 
 def update_module_dependencies(d):
     for mod in modulecode_deps:
         excludes = set((d.getVarFlag(mod, "vardepsexclude") or "").split())
         if excludes:
-            modulecode_deps[mod] = [modulecode_deps[mod][0] - excludes, modulecode_deps[mod][1] - excludes, modulecode_deps[mod][2] - excludes, modulecode_deps[mod][3], modulecode_deps[mod][4]]
+            modulecode_deps[mod] = [modulecode_deps[mod][0] - excludes, modulecode_deps[mod][1] - excludes, modulecode_deps[mod][2] - excludes, modulecode_deps[mod][3], modulecode_deps[mod][4], modulecode_deps[mod][5]]
 
 # A custom getstate/setstate using tuples is actually worth 15% cachesize by
 # avoiding duplication of the attribute names!
@@ -161,7 +164,7 @@ class CodeParserCache(MultiProcessCache):
     # so that an existing cache gets invalidated. Additionally you'll need
     # to increment __cache_version__ in cache.py in order to ensure that old
     # recipe caches don't trigger "Taskhash mismatch" errors.
-    CACHE_VERSION = 12
+    CACHE_VERSION = 14
 
     def __init__(self):
         MultiProcessCache.__init__(self)
@@ -261,7 +264,15 @@ class PythonParser():
 
     def visit_Call(self, node):
         name = self.called_node_name(node.func)
-        if name and (name.endswith(self.getvars) or name.endswith(self.getvarflags) or name in self.containsfuncs or name in self.containsanyfuncs):
+        if name and name in modulecode_deps and modulecode_deps[name][5]:
+            visitorcode = modulecode_deps[name][5]
+            contains, execs, warn = visitorcode(name, node.args)
+            for i in contains:
+                self.contains[i] = contains[i]
+            self.execs |= execs
+            if warn:
+                self.warn(node.func, warn)
+        elif name and (name.endswith(self.getvars) or name.endswith(self.getvarflags) or name in self.containsfuncs or name in self.containsanyfuncs):
             if isinstance(node.args[0], ast.Constant) and isinstance(node.args[0].value, str):
                 varname = node.args[0].value
                 if name in self.containsfuncs and isinstance(node.args[1], ast.Constant):