gdb/helper.py

   1 # -*- coding: utf-8 -*-
   2 # Helper module for pretty-printers
   3
   4 # Copyright (C) 2013 Kevin Funk <kfunk@kde.org>
   5
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 import sys
  20
  21 # BEGIN: Utilities for wrapping differences of Python 2.x and Python 3
  22 # Inspired by http://pythonhosted.org/six/
  23
  24 # Useful for very coarse version differentiation.
  25 PY2 = sys.version_info[0] == 2
  26 PY3 = sys.version_info[0] == 3
  27
  28 # create Python 2.x & 3.x compatible iterator base
  29 if PY3:
  30     Iterator = object
  31 else:
  32     class Iterator(object):
  33
  34         def next(self):
  35             return type(self).__next__(self)
  36 if PY3:
  37     unichr = chr
  38 else:
  39     unichr = unichr
  40
  41 # END
  42
  43 # BEGIN: Helper functions for pretty-printers
  44
  45 def has_field(val, name):
  46     """Check whether @p val (gdb.Value) has a field named @p name"""
  47     try:
  48         val[name]
  49         return True
  50     except Exception:
  51         return False
  52
  53 def default_iterator(val):
  54     for field in val.type.fields():
  55         yield field.name, val[field.name]
  56
  57 class FunctionLookup:
  58
  59     def __init__(self, gdb, pretty_printers_dict):
  60         self.gdb = gdb
  61         self.pretty_printers_dict = pretty_printers_dict
  62
  63     def __call__(self, val):
  64         "Look-up and return a pretty-printer that can print val."
  65
  66         # Get the type.
  67         type = val.type;
  68
  69         # If it points to a reference, get the reference.
  70         if type.code == self.gdb.TYPE_CODE_REF:
  71             type = type.target ()
  72
  73         # Get the unqualified type, stripped of typedefs.
  74         type = type.unqualified ().strip_typedefs ()
  75
  76         # Get the type name.
  77         typename = type.tag
  78         if typename == None:
  79             return None
  80
  81         # Iterate over local dictionary of types to determine
  82         # if a printer is registered for that type.  Return an
  83         # instantiation of the printer if found.
  84         for function in self.pretty_printers_dict:
  85             if function.search (typename):
  86                 return self.pretty_printers_dict[function](val)
  87
  88         # Cannot find a pretty printer.  Return None.
  89         return None
  90
  91 # END