source: rtems-tools/tools/gdb/python/supercore_printer.py @ a785e25

#
# RTEMS Supercore pretty printers for GDB
#
import objects
import itertools

class id_printer:
    """Print an object given the ID. Print using the struct display hint and an
    iterator."""

    class iterator:
        """Use an iterator for each field expanded from the id so GDB output
        is formatted correctly."""

        def __init__(self, id):
            self.id = id
            self.count = 0

        def __iter__(self):
            return self

        def next(self):
            self.count += 1
            if self.count == 1:
                return int(self.id.value())
            elif self.count == 2:
                return self.id.node()
            elif self.count == 3:
                return self.id.api()
            elif self.count == 4:
                return self.id._class()
            elif self.count == 5:
                return self.id.index()
            raise StopIteration

    def __init__(self, id):
        self.id = objects.ident(id)

    def to_string(self):
        return ''

    @staticmethod
    def key(i):
        if i == 0:
            return 'id'
        elif i == 1:
            return 'node'
        elif i == 2:
            return 'api'
        elif i == 3:
            return 'class'
        elif i == 4:
            return 'index'
        return 'bad'

    def children(self):
        counter = itertools.imap (self.key, itertools.count())
        return itertools.izip (counter, self.iterator(self.id))

    def display_hint (self):
        return 'struct'

class name_printer:
    """Pretty printer for an object's name. It has to guess the type as no
    information is available to help determine it."""

    def __init__(self, nameval):
        self.name = objects.name(nameval)

    def to_string(self):
        return str(self.name)

class control_printer:

    class iterator:
        """Use an iterator for each field expanded from the id so GDB output
        is formatted correctly."""

        def __init__(self, object):
            self.object = object
            self.count = 0

        def __iter__(self):
            return self

        def next(self):
            self.count += 1
            if self.count == 1:
                return self.object.node()
            elif self.count == 2:
                return self.object.id()
            elif self.count == 3:
                return self.object.name()
            raise StopIteration

    def to_string(self):
        return ''

    def __init__(self, object):
        self.object = objects.control(object)

    @staticmethod
    def key(i):
        if i == 0:
            return 'Node'
        elif i == 1:
            return 'id'
        elif i == 2:
            return 'name'
        return 'bad'

    def children(self):
        counter = itertools.imap (self.key, itertools.count())
        return itertools.izip (counter, self.iterator(self.object))

    def display_hint (self):
        return 'struct'


class state_printer:

    def __init__(self, state):
        self.state = threads.state(state)
    def to_string(self):
        return self.state.to_string()

class chains_printer:

    def __init__(self,chain):
        self.chain = chains.control(chain)

    def to_string(self):
        return "First:"+str(self.chain.first())+"\n Last:"+str(self.chain.last())

class node_printer:
    def __init__(self, node):
        self.node = chains.node(node)

    def to_string(self):
        return "Node: "+str(self.node)+" Next: "+str(self.node.next())+" Prev: "+str(self.node.previous())