ng_gdb.py

import re
import itertools
import gdb
from gdb.FrameDecorator import FrameDecorator
from gdb.FrameDecorator import SymValueWrapper

#
# Pretty printing for layoutng
#
# 1) NGBlockNode -> prints layout_box_->debugName()
#
# 2) backtrace decorates NGBlockNode lines with NGBlockNode->debugName
#
# Backtrace decoration
# Prints pretty names for NGBlockNode, LayoutNGBlockFlow
#
class NGFrameDecorator(FrameDecorator):

  ng_block_re = re.compile('^blink::NGBlockNode')
  ng_block_painter_re = re.compile('^blink::BlockPainter')
  std_re = re.compile('^std::__')
  def __init__(self, fobj):
    super(NGFrameDecorator, self).__init__(fobj)

  def function(self):
    frame = self._base.inferior_frame()
    name = str(frame.name())
    try:
      if NGFrameDecorator.ng_block_re.match(name):
        symbol = frame.read_var('this')
        name = '#? {0} {1}'.format(name, symbol[0])
      if NGFrameDecorator.ng_block_painter_re.match(name):
        symbol = frame.read_var('this')
        name = '#? {0} {1}'.format(name, symbol[0])
      if NGFrameDecorator.ng_block_painter_re.match(name):
        name = 'std::stuff'
    except:
      name = name

    return name

  def address(self):
    return None

  def frame_args(self):
    # return FrameDecorator.frame_args(self)
    return None

  def filename(self):
    return ""

  def frame_locals(self):
    return None

class NGFrameFilter():
  def __init__(self):
    self.name = "NGFilter"
    self.priority = 100
    self.enabled = True

    # Register this frame filter with the global frame_filters
    # dictionary.
    gdb.frame_filters[self.name] = self

  def filter(self, frame_iter):
    frame_iter = itertools.imap(NGFrameDecorator, frame_iter)
    return frame_iter

# install frame filter
NGFrameFilter()

#
# Pretty printers
#
class NGBlockNodePrinter(object):
  "Print blink::NGBlockNode"

  class_name_match = re.compile("^blink::NGBlockNode$")

  @staticmethod
  def can_print(lookup_tag):
    return NGBlockNodePrinter.class_name_match.match(lookup_tag)

  def __init__(self, val):
    self.val = val

  def to_string(self):
    # if layout_box_ call layout_box_->debugName()
    if not self.val['box_']:
      return "no box_";
    eval_string = "((blink::LayoutBox*)%s)->DebugName()" % self.val['box_'].dereference().address
    return gdb.parse_and_eval(eval_string);

  def display_hint(self):
    return 'string'

class LayoutObjectPrinter(object):
  "Print blink::LayoutObject"

  def __init__(self, val):
    self.val = val

  def to_string(self):
    # if layout_box_ call layout_box_->debugName()
    if not self.val['box_']:
      return "no box_";
    eval_string = "((blink::LayoutObject*)%s)->DebugName()" % self.val.address
    return gdb.parse_and_eval(eval_string);

  def display_hint(self):
    return 'string'

class BlockPainterPrinter(object):
  "Print blink::BlockPainter with Node info"

  def __init__(self, val):
    self.val = val

  def to_string(self):
    if not self.val['layout_block_']:
      return "no layout_block_";
    eval_string = "((blink::LayoutBlock*)%s)->DebugName()" % self.val['layout_block_'].address
    return gdb.parse_and_eval(eval_string);

  def display_hint(self):
    return 'string'

class BaseOptionalPrinter(object):
  "Print base::Optional"

  class_name_match = re.compile("^base::Optional<")

  @staticmethod
  def can_print(lookup_tag):
    return BaseOptionalPrinter.class_name_match.match(lookup_tag)

  def __init__(self, val):
    self.val = val

  def to_string(self):
    if self.val['storage_']['is_populated_']:
      return "Optional< %s >" % self.val['storage_']['value_']
    else:
      return "Optional<>"

def ng_pretty_printer_lookup_function(val):
  lookup_tag = val.type.tag
  if lookup_tag == None:
    return None
  block_node = re.compile("^blink::NGBlockNode$")
  input_node = re.compile("^blink::NGLayoutInputNode$")
  block_painter = re.compile("^blink::BlockPainter$")
  layout_block = re.compile("^blink::LayoutBlock$")
  layout_image = re.compile("^blink::LayoutImage$")
  if NGBlockNodePrinter.can_print(lookup_tag):
    return NGBlockNodePrinter(val)
  if input_node.match(lookup_tag):
    return NGBlockNodePrinter(val)
  if block_painter.match(lookup_tag):
    return BlockPainterPrinter(val)
  if BaseOptionalPrinter.can_print(lookup_tag):
    return BaseOptionalPrinter(val)
  if layout_block.match(lookup_tag) or layout_image.match(lookup_tag):
    return LayoutObjectPrinter(val)
  return None

# install pretty printers
gdb.pretty_printers.append(ng_pretty_printer_lookup_function)
print("ng_gdb loaded")