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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# You can obtain one at http://mozilla.org/MPL/2.0/.
# Pretty-printers for SpiderMonkey JSObjects.
import re
import gdb
import mozilla.prettyprinters as prettyprinters
from mozilla.prettyprinters import ptr_pretty_printer, ref_pretty_printer
from mozilla.Root import deref
from mozilla.CellHeader import get_header_ptr
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("JSClass::NON_NATIVE")
self.NativeObject_ptr_t = gdb.lookup_type("js::NativeObject").pointer()
self.BaseShape_ptr_t = gdb.lookup_type("js::BaseShape").pointer()
self.Shape_ptr_t = gdb.lookup_type("js::Shape").pointer()
self.ObjectGroup_ptr_t = gdb.lookup_type("js::ObjectGroup").pointer()
self.JSClass_ptr_t = gdb.lookup_type("JSClass").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 = get_header_ptr(self.value, self.otc.ObjectGroup_ptr_t)
classp = get_header_ptr(group, self.otc.JSClass_ptr_t)
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 = get_header_ptr(shape, self.otc.BaseShape_ptr_t)
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)
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