# Pretty-printers for SpiderMonkey JSObjects. import re import gdb import mozilla.JSString import mozilla.prettyprinters as prettyprinters from mozilla.prettyprinters import ptr_pretty_printer, ref_pretty_printer from mozilla.Root import deref prettyprinters.clear_module_printers(__name__) class JSObjectTypeCache(object): def __init__(self, value, cache): baseshape_flags = gdb.lookup_type('js::BaseShape::Flag') self.flag_DELEGATE = prettyprinters.enum_value(baseshape_flags, 'js::BaseShape::DELEGATE') self.func_ptr_type = gdb.lookup_type('JSFunction').pointer() self.class_NON_NATIVE = gdb.parse_and_eval('js::Class::NON_NATIVE') self.NativeObject_ptr_t = gdb.lookup_type('js::NativeObject').pointer() # There should be no need to register this for JSFunction as well, since we # search for pretty-printers under the names of base classes, and # JSFunction has JSObject as a base class. gdb_string_regexp = re.compile(r'(?:0x[0-9a-z]+ )?(?:<.*> )?"(.*)"', re.I) @ptr_pretty_printer('JSObject') class JSObjectPtrOrRef(prettyprinters.Pointer): def __init__(self, value, cache): super(JSObjectPtrOrRef, self).__init__(value, cache) if not cache.mod_JSObject: cache.mod_JSObject = JSObjectTypeCache(value, cache) self.otc = cache.mod_JSObject def summary(self): group = deref(self.value['group_']) classp = group['clasp_'] non_native = classp['flags'] & self.otc.class_NON_NATIVE # Use GDB to format the class name, but then strip off the address # and the quotes. class_name = str(classp['name']) m = gdb_string_regexp.match(class_name) if m: class_name = m.group(1) if non_native: return '[object {}]'.format(class_name) else: native = self.value.cast(self.otc.NativeObject_ptr_t) shape = deref(native['shape_']) baseshape = deref(shape['base_']) flags = baseshape['flags'] is_delegate = bool(flags & self.otc.flag_DELEGATE) name = None if class_name == 'Function': function = self.value concrete_type = function.type.strip_typedefs() if concrete_type.code == gdb.TYPE_CODE_REF: function = function.address function = function.cast(self.otc.func_ptr_type) atom = deref(function['atom_']) name = str(atom) if atom else '<unnamed>' return '[object {}{}]{}'.format(class_name, ' ' + name if name else '', ' delegate' if is_delegate else '') @ref_pretty_printer('JSObject') def JSObjectRef(value, cache): return JSObjectPtrOrRef(value, cache)