#----------------------------------------------------------------------------
# Name:         IsolatedDebugger.py
# Purpose:      A Bdb-based debugger (tracer) that can be operated by
#               another process
#
# Authors:      Shane Hathaway, Riaan Booysen
#
# Created:      November 2000
# RCS-ID:       $Id: IsolatedDebugger.py,v 1.28 2004/08/16 13:18:53 riaan Exp $
# Copyright:    (c) 2000 - 2004 : Shane Hathaway, Riaan Booysen
# Licence:      GPL
#----------------------------------------------------------------------------

import sys, thread, threading, Queue
import pprint
from os import chdir
from os import path
import bdb
from bdb import Bdb, BdbQuit, Breakpoint
from repr import Repr
from types import TupleType


# XXX Extend breakpoints to break on exception (like conditional breakpoints)

__traceable__ = 0      # Never trace the tracer.
bdb.__traceable__ = 0


class DebugError(Exception):
    """Incorrect operation of the debugger"""

class BreakpointError(DebugError):
    """Incorrect operation on a breakpoint"""


class DebuggerConnection:
    """A debugging connection that can be operated via RPC.
    """

    def __init__(self, ds):
        """Creates a DebuggerConnection that wraps around a DebugServer."""
        self._ds = ds

    def _callNoWait(self, func_name, do_return, *args, **kw):
        sm = MethodCall(func_name, args, kw, do_return)
        sm.setWait(0)
        self._ds.queueServerMessage(sm)

    def _callMethod(self, func_name, do_return, *args, **kw):
        sm = MethodCall(func_name, args, kw, do_return)
        sm.setupEvent()
        self._ds.queueServerMessage(sm)
        # Block.
        res = sm.getResult()
        return res

    ### Non-blocking calls.

    def allowEnvChanges(self, allow=1):
        """Allows the debugger to set sys.path, sys.argv, and
        use os.chdir().
        """
        self._ds._allow_env_changes = allow

    def run(self, cmd, globals=None, locals=None):
        """Starts debugging.  Stops the process at the
        first source line.  Non-blocking.
        """
        self._callNoWait('run', 1, cmd, globals, locals)

    def runFile(self, filename, params=(), autocont=0, add_paths=()):
        """Starts debugging.  Stops the process at the
        first source line.  Use the autocont parameter to proceed immediately
        rather than stop.  Non-blocking.
        """
        self._callNoWait('runFile', 1, filename, params, autocont, add_paths)
    
    def post_mortem(self):
        """ Inspecting tracebacks in the debugger 
        """
        self._callMethod('post_mortem', 0)

    def set_continue(self, full_speed=0):
        """Proceeds until a breakpoint or program stop.
        Non-blocking.
        """
        self._callNoWait('set_continue', 1, full_speed)

    def set_step(self):
        """Steps to the next instruction.  Non-blocking.
        """
        self._callNoWait('set_step', 1)

    def set_step_out(self):
        """Proceeds until the process returns from the current
        stack frame.  Non-blocking."""
        self._callNoWait('set_step_out', 1)

    def set_step_over(self):
        """Proceeds to the next source line in the current frame
        or above.  Non-blocking."""
        self._callNoWait('set_step_over', 1)

    def set_step_jump(self, lineno):
        """Updates the lineno of the bottom frame.  Non-blocking."""
        self._callMethod('set_step_jump', 0, lineno)
    
    def set_pause(self):
        """Stops as soon as possible.  Non-blocking and immediate.
        """
        self._ds.stopAnywhere()

    def set_quit(self):
        """Attempts to quits debugging, executing only the try/finally
        handlers.  Non-blocking.
        """
        self._callNoWait('set_quit', 1)

    def set_disconnect(self):
        """Raises a BdbQuit exception in the current thread then
        allows other threads to continue.  Non-blocking.
        """
        self._callNoWait('set_disconnect', 1)

    def setAllBreakpoints(self, brks):
        """brks is a list of mappings containing the keys:
        filename, lineno, temporary, enabled, and cond.
        Non-blocking and immediate."""
        self._ds.setAllBreakpoints(brks)

    def addBreakpoint(self, filename, lineno, temporary=0,
                      cond='', enabled=1, ignore=0):
        """Sets a breakpoint.  Non-blocking and immediate.
        """
        self._ds.addBreakpoint(filename, lineno, temporary,
                               cond, enabled, ignore)

    def enableBreakpoints(self, filename, lineno, enabled=1):
        """Sets the enabled flag for all breakpoints on a given line.
        Non-blocking and immediate.
        """
        self._ds.enableBreakpoints(filename, lineno, enabled)

    def ignoreBreakpoints(self, filename, lineno, ignore=0):
        """Sets the ignore flag for all breakpoints on a given line.
        Non-blocking and immediate.
        """
        self._ds.ignoreBreakpoints(filename, lineno, ignore)

    def conditionalBreakpoints(self, filename, lineno, cond=''):
        """Sets the break condition for all breakpoints on a given line.
        Non-blocking.
        """
        self._ds.conditionalBreakpoints(filename, lineno, cond)

    def clearBreakpoints(self, filename, lineno):
        """Clears all breakpoints on a line.
        Non-blocking and immediate.
        """
        self._ds.clearBreakpoints(filename, lineno)

    def adjustBreakpoints(self, filename, lineno, delta):
        """Moves all applicable breakpoints when delta lines are added or
        deleted.
        Non-blocking and immediate.
        """
        self._ds.adjustBreakpoints(filename, lineno, delta)

    ### Blocking methods.

    def pprintVarValue(self, name, frameno):
        """Pretty-prints the value of name.  Blocking."""
        return self._callMethod('pprintVarValue', 0, name, frameno)

    def getStatusSummary(self):
        """Returns a mapping containing the keys:
          exc_type, exc_value, stack, frame_stack_len, running.
        Also returns and empties the stdout and stderr buffers.
        stack is a list of mappings containing the keys:
          filename, lineno, funcname, modname.
        breaks contains the breakpoint statistics information
          for all current breakpoints.
        The most recent stack entry will be at the last
        of the list.  Blocking.
        """
        return self._callMethod('getStatusSummary', 0)

    def proceedAndRequestStatus(self, command, temp_breakpoint=0, args=()):
        """Executes one non-blocking command then returns
        getStatusSummary().  Blocking."""
        if temp_breakpoint:
            self.addBreakpoint(temp_breakpoint[0], temp_breakpoint[1], 1)
        if command:
            allowed = ('set_continue', 'set_step', 'set_step_over',
                       'set_step_out', 'set_pause', 'set_quit',
                       'set_disconnect', 'set_step_jump')
            if command not in allowed:
                raise DebugError('Illegal command: %s' % command)
            apply(getattr(self, command), args)
        ss = self.getStatusSummary()
        return ss

    def runFileAndRequestStatus(self, filename, params=(), autocont=0,
                                add_paths=(), breaks=()):
        """Calls setAllBreakpoints(), runFile(), and
        getStatusSummary().  Blocking."""
        self.setAllBreakpoints(breaks)
        self._callNoWait('runFile', 1, filename, params, autocont, add_paths)
        return self.getStatusSummary()

    def setupAndRequestStatus(self, autocont=0, breaks=()):
        """Calls setAllBreakpoints() and
        getStatusSummary().  Blocking."""
        self.setAllBreakpoints(breaks)
        if autocont:
            self.set_continue()
        else:
            self._ds.set_step()
        return self.getStatusSummary()

    def getSafeDict(self, locals, frameno):
        """Returns the repr-fied mappings of locals and globals in a
        tuple.  Blocking."""
        return self._callMethod('getSafeDict', 0, locals, frameno)

    def evaluateWatches(self, exprs, frameno):
        """Evalutes the watches listed in exprs and returns the
        results. Input is a tuple of mappings with keys name and
        local; output is a mapping of name -> svalue.  Blocking.
        """
        return self._callMethod('evaluateWatches', 0, exprs, frameno)

    def getWatchSubobjects(self, expr, frameno):
        """Returns a tuple containing the names of subobjects
        available through the given watch expression.  Blocking."""
        return self._callMethod('getWatchSubobjects', 0, expr, frameno)

##    def updateBottomOfStackCodeObject(self, code):
##        """ Experimental
##        """
##        return self._callMethod('updateBottomOfStackCodeObject', 0, code)

class NonBlockingDebuggerConnection (DebuggerConnection):
    """Modifies call semantics in such a way that even blocking
    calls don't block but instead return None.
    Note that for each call, a new NonBlockingDebuggerConnection object
    has to be created.  Use setCallback() to receive notification when
    blocking calls are finished.
    """

    callback = None

    def setCallback(self, callback):
        self.callback = callback

    def _callMethod(self, func_name, do_return, *args, **kw):
        sm = MethodCall(func_name, args, kw, do_return)
        if self.callback:
            sm.setCallback(self.callback)
        self._ds.queueServerMessage(sm)
        return None


# Set exclusive mode to kill all existing debug servers whenever
# a new connection is created.  This helps avoid resource drains.
exclusive_mode = 1


class DebuggerController:
    """Interfaces between DebuggerConnections and DebugServers."""

    def __init__(self):
        self._debug_servers = {}
        self._next_server_id = 0
        self._server_id_lock = threading.Lock()
        self._message_timeout = None

    def _newServerId(self):
        self._server_id_lock.acquire()
        try:
            id = str(self._next_server_id)
            self._next_server_id = self._next_server_id + 1
        finally:
            self._server_id_lock.release()
        return id

    def createServer(self):
        """Returns a string which identifies a new DebugServer.
        """
        global exclusive_mode
        if exclusive_mode:
            # Kill existing servers.
            for id in self._debug_servers.keys():
                self.deleteServer(id)
        ds = DebugServer()
        id = self._newServerId()
        self._debug_servers[id] = ds
        return id

    def deleteServer(self, id):
        """Terminates the connection to the DebugServer."""
        try:
            ds = self._debug_servers[id]
            ds.set_quit()
            self._deleteServer(id)
        except: pass

    def _deleteServer(self, id):
        del self._debug_servers[id]

    def _getDebugServer(self, id):
        return self._debug_servers[id]

    def getMessageTimeout(self):
        return self._message_timeout


class ServerMessage:
    def setupEvent(self):
        self.event = threading.Event()

    def wait(self, timeout=None):
        if hasattr(self, 'event'):
            self.event.wait()

    def doExecute(self): return 0
    def doReturn(self): return 0
    def doExit(self): return 0
    def execute(self, ds): pass

class MethodCall (ServerMessage):
    def __init__(self, func_name, args, kw, do_return):
        self.func_name = func_name
        self.args = args
        self.kw = kw
        self.do_return = do_return
        self.waiting = 1

    def setWait(self, val):
        self.waiting = val

    def doExecute(self):
        return 1

    def execute(self, ob):
        try:
            result = apply(getattr(ob, self.func_name), self.args, self.kw)
        except (SystemExit, BdbQuit):
            raise
        except:
            if hasattr(self, 'callback'):
                self.callback.notifyException()
            else:
                if self.waiting:
                    self.exc = sys.exc_info()
                else:
                    # No one will see this message otherwise.
                    import traceback
                    traceback.print_exc()
        else:
            if hasattr(self, 'callback'):
                self.callback.notifyReturn(result)
            else:
                self.result = result

        if hasattr(self, 'event'):
            self.event.set()

    def doReturn(self):
        return self.do_return

    def setCallback(self, callback):
        self.callback = callback

    def getResult(self, timeout=None):
        self.wait()
        if hasattr(self, 'exc'):
            try:
                raise self.exc[0], self.exc[1], self.exc[2]
            finally:
                # Circ ref
                del self.exc
        if not hasattr(self, 'result'):
            raise DebugError, 'Timed out while waiting for debug server.'
        return self.result



class ThreadChoiceLock:
    """A reentrant lock designed for simply choosing a thread.
    It is always released when you call release()."""

    def __init__(self):
        self._owner = None
        self._block = thread.allocate_lock()

    def acquire(self, blocking=1):
        me = thread.get_ident()
        if self._owner == me:
            return 1
        rc = self._block.acquire(blocking)
        if rc:
            self._owner = me
        return rc

    def release(self):
        me = thread.get_ident()
        assert me == self._owner, "release of unacquired lock"
        self._owner = None
        self._block.release()

    def releaseIfOwned(self):
        me = thread.get_ident()
        if me == self._owner:
            self.release()


_orig_syspath = sys.path

class DebugServer (Bdb):

    # frame is set only while paused.
    frame = None

    # exc_info is set only while paused and an exception occurred.
    exc_info = None

    # starting_trace is set to make sure sys.set_trace() gets called before
    # resuming user code.
    starting_trace = 0

    # ignore_stopline is the line number we should *not* stop on.
    ignore_stopline = -1

    # autocont is set by runFile() if the debugger should enter set_continue
    # mode right after starting.
    autocont = 0

    # _allow_env_changes governs whether sys.path, etc. can be modified.
    _allow_env_changes = 0

    # quitting is set to true when the user clicks the stop button.
    quitting = 0

    # stopframe can hold several values:
    #   None: Stop anywhere
    #   frame object: Stop in that frame
    #   (): Stop nowhere

    def __init__(self):
        Bdb.__init__(self)
        self.fncache = {}
        self.botframe = None

        self.__queue = Queue.Queue(0)

        # self._lock governs which thread the debugger will stop in.
        self._lock = ThreadChoiceLock()

        self.repr = repr = Repr()
        repr.maxstring = 100
        repr.maxother = 100
        self.maxdict2 = 1000

        self._running = 0
        self.cleanupServer()
        self.stopframe = ()  # Don't stop unless requested to do so.

    def queueServerMessage(self, sm):
        self.__queue.put(sm)

    def cleanupServer(self):
        self.reset()
        self.frame = None
        self.ignore_stopline = -1
        self.autocont = 0
        self.exc_info = None
        self.starting_trace = 0
        self.fncache.clear()
        self._lock.releaseIfOwned()

    def servicerThread(self):
        """Bootstraps the debugger server loop."""
        while 1:
            try:
                self.eventLoop()
            except:
                # ??
                import traceback
                traceback.print_exc()
            self.quitting = 0

    def eventLoop(self):
        while not self.quitting:
            if not self.executeOneEvent():
                break  # event requested a return

    def executeOneEvent(self):
        # The heart of this whole mess.  Fetches a message and executes
        # it in the current frame.
        # Should not catch exceptions.
        sm = self.__queue.get()
        if sm.doExecute():
            sm.execute(self)
        if sm.doExit():
            thread.exit()
        if sm.doReturn():
            # Return to user code
            self.beforeResume()
            if self.starting_trace:
                self.starting_trace = 0
                sys.settrace(self.trace_dispatch)
            return 0
        return 1

    def beforeResume(self):
        """Frees references before jumping back into user code."""
        self.frame = None
        self.exc_info = None

    # Bdb overrides.
    def canonic(self, filename):
        canonic = self.fncache.get(filename, None)
        if not canonic:
            if ((filename[:1] == '<' and filename[-1:] == '>') or
                filename.find('://') >= 0):
                # Don't change URLs or special filenames
                canonic = filename
            else:
                canonic = path.abspath(filename)

            self.fncache[filename] = canonic
        return canonic

    def getFilenameAndLine(self, frame):
        """Returns the filename and line number for the frame.
        """
        filename = self.canonic(frame.f_code.co_filename)
        return filename, frame.f_lineno

    def getFrameNames(self, frame):
        """Returns the module and function name for the frame.
        """
        try:
            modname = frame.f_globals['__name__']
        except KeyError:
            modname = ''
        if modname is None:
            modname = ''
        funcname = frame.f_code.co_name
        return modname, funcname

    def isTraceable(self, frame):
        return frame.f_globals.get('__traceable__', 1)

    def break_here(self, frame):
        filename, lineno = self.getFilenameAndLine(frame)
        if not self.breaks.has_key(filename):
            return 0

        if not lineno in self.breaks[filename]:
            return 0
        # flag says ok to delete temp. bp
        (bp, flag) = bdb.effective(filename, lineno, frame)
        if bp:
            self.currentbp = bp.number
            if (flag and bp.temporary):
                self.do_clear(str(bp.number))
            self.afterBreakpoint(frame)
            return 1
        else:
            return 0

    def break_anywhere(self, frame):
        filename, lineno = self.getFilenameAndLine(frame)
        return self.breaks.has_key(filename)

    def stop_here(self, frame):
        # Redefine stopping.
        if frame is self.botframe:
            # Don't stop in the bottom frame.
            return 0
        sf = self.stopframe
        if sf is None:
            # Stop anywhere.
            return self.isTraceable(frame)
        elif sf is ():
            # Stop nowhere.
            return 0
        # else stop in a specific frame.
        if (frame is sf and frame.f_lineno != self.ignore_stopline):
            # Stop in the current frame unless we're on
            # ignore_stopline.
            return self.isTraceable(frame)
        # Stop at any frame that called stopframe.
        f = sf
        while f:
            if frame is f:
                return self.isTraceable(frame)
            f = f.f_back
        return 0

    def add_trace_hooks(self, frame):
        root_frame = None
        f = frame
        td = self.trace_dispatch
        while f:
            f.f_trace = td
            root_frame = f
            f = f.f_back
            if f is self.botframe:
                break
        if self.botframe is None:
            # Make the entire stack visible.
            self.botframe = root_frame

    def remove_trace_hooks(self):
        sys.settrace(None)
        try:
            raise 'gen_exc_info'
        except:
            frame = sys.exc_info()[2].tb_frame
            while frame:
                # Clear all the f_trace attributes
                # that were created while processing with a
                # settrace callback enabled.
                del frame.f_trace
                if frame is self.botframe:
                    break
                frame = frame.f_back

    def set_continue(self, full_speed=0):
        """Only stop at breakpoints, exceptions or when finished.
        """
        self.stopframe = ()
        self.returnframe = None
        self.quitting = 0

        if full_speed:
            # run without debugger overhead
            self.starting_trace = 0
            self.remove_trace_hooks()
        else:
            self.starting_trace = 1

        # Allow a stop in any thread.
        self._lock.releaseIfOwned()

    def set_disconnect(self):
        """Debugging client disconnected.  Raise a quit exception in just
        this thread, but allow other threads to continue.
        """
        self.set_continue(1)
        raise BdbQuit, 'Client disconnected'

    def set_traceable(self, enable=1):
        """Allows user code to enable/disable tracing without changing the
        stepping mode.
        """
        sys.settrace(None)
        self._running = 1
        if enable:
            # Add trace hooks.
            try:
                raise 'gen_exc_info'
            except:
                frame = sys.exc_info()[2].tb_frame.f_back
            self.add_trace_hooks(frame)
            sys.settrace(self.trace_dispatch)
        else:
            # Remove trace hooks and allow other threads to capture the lock.
            self.remove_trace_hooks()
            self._lock.releaseIfOwned()

    def hard_break_here(self, frame):
        """Indicates whether the debugger should stop at a hard breakpoint.

        Returns a (filename, lineno) tuple if the debugger should also
        set a soft breakpoint.
        """
        filename, lineno = self.getFilenameAndLine(frame)
        brks = self.breaks.get(filename, None)
        if brks is None or lineno not in brks:
            # No soft breakpoint has been set, so plan to add the soft
            # breakpoint and stop.
            return (filename, lineno)
        # Let the soft breakpoint control whether the hard breakpoint
        # takes effect.
        return self.break_here(frame)

    def set_trace(self):
        """Start debugging from the caller's frame.

        Called by hard breakpoints.
        """
        try:
            raise 'gen_exc_info'
        except:
            frame = sys.exc_info()[2].tb_frame.f_back
        stop = self.hard_break_here(frame)
        if not stop:
            # The user has disabled this breakpoint.
            return
        if not self._lock.acquire(0):
            # The debugger is busy in another thread.
            return

        if isinstance(stop, TupleType):
            # Add a soft breakpoint here so the user can manage the breakpoint.
            filename, lineno = stop
            self.set_break(filename, lineno)
        self._running = 1
        self.add_trace_hooks(frame)
        # Get sys.settrace() called when resuming.
        self.starting_trace = 1
        self.afterBreakpoint(frame)
        # Pause in the frame
        self.user_line(frame)

    def afterBreakpoint(self, frame):
        # Set a default stepping mode.
        self.set_step()

    def set_internal_breakpoint(self, filename, lineno, temporary=0,
                                cond=None):
        if not self.breaks.has_key(filename):
            self.breaks[filename] = []
        list = self.breaks[filename]
        if not lineno in list:
            list.append(lineno)

    def set_break(self, filename, lineno, temporary=0, cond=None):
        filename = self.canonic(filename)
        self.set_internal_breakpoint(filename, lineno, temporary, cond)
        # Note that we can't reliably verify a filename anymore.
        return bdb.Breakpoint(filename, lineno, temporary, cond)

    def do_clear(self, bpno):
        self.clear_bpbynumber(bpno)

    def clearTemporaryBreakpoints(self, filename, lineno):
        filename = self.canonic(filename)
        if not self.breaks.has_key(filename):
            return
        if lineno not in self.breaks[filename]:
            return
        # If all bp's are removed for that file,line
        # pair, then remove the breaks entry
        for bp in Breakpoint.bplist[filename, lineno][:]:
            if bp.temporary:
                bp.deleteMe()
        if not Breakpoint.bplist.has_key((filename, lineno)):
            self.breaks[filename].remove(lineno)
        if not self.breaks[filename]:
            del self.breaks[filename]

    # Bdb callbacks.

    def user_line(self, frame):
        # This method is called when we stop or break at a line
        if not self._lock.acquire(0):
            # Already working in another thread.
            return
        if self.autocont:
            self.autocont = 0
            self.set_continue()
            return
        self.stopframe = ()  # Don't stop.
        self.ignore_stopline = -1
        self.frame = frame
        self.exc_info = None
        filename, lineno = self.getFilenameAndLine(frame)
        self.clearTemporaryBreakpoints(filename, lineno)
        self.eventLoop()

    def user_return(self, frame, return_value):
        # This method is called when stepping in or next,
        # but not when stepping out.
        frame.f_locals['__return__'] = return_value
        self.user_line(frame)

    def user_exception(self, frame, exc_info):
        # This method should be used to automatically stop
        # when specific exception types occur.
        #self.ignore_stopline = -1
        #self.frame = frame
        #self.exc_info = exc_info
        #self.eventLoop()
        pass

    ### Utility methods.
    def stopAnywhere(self):
        self.stopframe = None
        self.returnframe = None

    def runFile(self, filename, params, autocont, add_paths):
        d = {'__name__': '__main__',
             '__doc__': 'Debugging',
             '__builtins__': __builtins__,}

        fn = self.canonic(filename)
        if self._allow_env_changes:
            bn = path.basename(fn)
            dn = path.dirname(fn)
            sys.argv = [bn] + list(params)
            if not add_paths:
                add_paths = []
            sys.path = [dn] + list(add_paths) + list(_orig_syspath)
            chdir(dn)

        self.autocont = autocont

        self.run("execfile(fn, d)", {
            'fn':fn, 'd':d, '__debugger__': self})

    def run(self, cmd, globals=None, locals=None):
        try:
            self._running = 1
            try:
                Bdb.run(self, cmd, globals, locals)
            except (BdbQuit, SystemExit):
                pass
            except:
                import traceback
                traceback.print_exc()
                if self._lock.acquire(0):
                    # Provide post-mortem analysis.
                    self.exc_info = sys.exc_info()
                    self.frame = self.exc_info[2].tb_frame
                    self.quitting = 0
                    self.eventLoop()
        finally:
            sys.settrace(None)  # Just to be sure
            self.quitting = 1
            self._running = 0
            self.cleanupServer()

    def isRunning(self):
        return self._running
    
    def post_mortem(self, exc_info=None):
        if exc_info is None:
            self.exc_info = sys.exc_info()
        else:
            self.exc_info = exc_info
            
        if self.exc_info[2] is not None:
            self.frame = self.exc_info[2].tb_frame
        else:
            self.frame = None    

        self._running = 1
        self.quitting = 0
        self.eventLoop()

    def set_step_out(self):
        """Stop when returning from the topmost frame."""
        frame = self.getFrameByNumber(-1)
        if frame is not None:
            self.stopframe = frame.f_back
            self.returnframe = None
            self.quitting = 0
        else:
            raise DebugError('No current frame')

    def set_step_over(self):
        """Stop on the next line in the topmost frame or in one of its callers.
        """
        frame = self.getFrameByNumber(-1)
        if frame is not None:
            # ignore_stopline is brittle for scripts.
            #self.ignore_stopline = frame.f_lineno
            self.set_next(frame)
        else:
            raise DebugError('No current frame')
        
    def set_step_jump(self, lineno):
        """ Adjust the linenumber attribute of the bottom frame """
        frame = self.getFrameByNumber(-1)
        if frame is not None:
            frame.f_lineno = lineno
        else:
            raise DebugError('No current frame')
    

    ### Breakpoint control.
    def setAllBreakpoints(self, brks):
        """brks is a list of mappings containing the keys:
        filename, lineno, temporary, enabled, and cond.
        Non-blocking."""
        self.clear_all_breaks()
        if brks:
            for brk in brks:
                apply(self.addBreakpoint, (), brk)

    def addBreakpoint(self, filename, lineno, temporary=0,
                      cond='', enabled=1, ignore=0):
        """Sets a breakpoint.  Non-blocking.
        """
        bp = self.set_break(filename, lineno, temporary, cond)
        if type(bp) == type(''):
            # Note that checking for string type is strange. Argh.
            raise BreakpointError(bp)
        elif bp is not None and not enabled:
            bp.disable()
        bp.ignore = ignore

    def enableBreakpoints(self, filename, lineno, enabled=1):
        """Sets the enabled flag for all breakpoints on a given line.
        Non-blocking.
        """
        bps = self.get_breaks(filename, lineno)
        if bps:
            for bp in bps:
                if enabled: bp.enable()
                else: bp.disable()

    def ignoreBreakpoints(self, filename, lineno, ignore=0):
        """Sets the ignore count for all breakpoints on a given line.
        Non-blocking.
        """
        bps = self.get_breaks(filename, lineno)
        if bps:
            for bp in bps:
                bp.ignore = ignore

    def conditionalBreakpoints(self, filename, lineno, cond=''):
        """Sets the break condition for all breakpoints on a given line.
        Non-blocking.
        """
        bps = self.get_breaks(filename, lineno)
        if bps:
            for bp in bps:
                bp.cond = cond

    def clearBreakpoints(self, filename, lineno):
        """Clears all breakpoints on a line.
        Non-blocking.
        """
        msg = self.clear_break(filename, lineno)
        if msg is not None:
            raise BreakpointError(msg)

    def adjustBreakpoints(self, filename, lineno, delta):
        """Moves all applicable breakpoints when delta lines are added or
        deleted.
        Non-blocking.
        """
        # This can be more efficient, but for now sticking to the bdb interface
        # Unfortunately this must be done on a low level
        filename = self.canonic(filename)
        breaklines = self.get_file_breaks(filename)
        bplist = bdb.Breakpoint.bplist
        set_breaks = []
        # store reference and remove from (fn, ln) refed dict.
        for line in breaklines[:]:
            if line > lineno:
                set_breaks.append(self.get_breaks(filename, line))
                breaklines.remove(line)
                del bplist[filename, line]
        # put old break at new place and renumber
        for brks in set_breaks:
            for brk in brks:
                brk.line = brk.line + delta
                breaklines.append(brk.line)
                # merge in moved breaks
                if bplist.has_key((filename, brk.line)):
                    bplist[filename, brk.line].append(brk)
                else:
                    bplist[filename, brk.line] = [brk]
        # reorder lines
        breaklines.sort()

    def getStackInfo(self):
        try:
            if self.exc_info is not None:
                exc_type, exc_value, exc_tb = self.exc_info
                try:
                    exc_type = exc_type.__name__
                except AttributeError:
                    # Python 2.x -> ustr()?
                    exc_type = "%s" % str(exc_type)
                if exc_value is not None:
                    exc_value = str(exc_value)

                stack, frame_stack_len = self.get_stack(
                    exc_tb.tb_frame, exc_tb)
            else:
                exc_type = None
                exc_value = None
                stack, frame_stack_len = self.get_stack(
                    self.frame, None)
            # Remove debugger's own stack.
            for index in range(len(stack)):
                g = stack[index][0].f_globals
                if g.get('__debugger__', None) is self:
                    stack = stack[index + 1:]
                    frame_stack_len = frame_stack_len - (index + 1)
                    break
            return exc_type, exc_value, stack, frame_stack_len
        finally:
            exc_tb = None
            stack = None

    def getFrameByNumber(self, frameno):
        """Gets the specified frame number from the stack.

        Returns None if the stack is not available.
        """
        try:
            stack = self.getStackInfo()[2]
            if stack:
                if frameno >= len(stack):
                    # Should we be doing this?
                    frameno = len(stack) - 1
                return stack[frameno][0]
            else:
                return None
        finally:
            stack = None

    def getFrameNamespaces(self, frame):
        """Returns the locals and globals for a frame.

        Can be overridden for high-level scripts.
        """
        return frame.f_globals, frame.f_locals

    def getExtendedFrameInfo(self):
        try:
            (exc_type, exc_value, stack,
             frame_stack_len) = self.getStackInfo()
            stack_summary = []
            for frame, lineno in stack:
                filename, lineno = self.getFilenameAndLine(frame)
                modname, funcname = self.getFrameNames(frame)
                stack_summary.append(
                    {'filename':filename, 'lineno':lineno,
                     'funcname':funcname, 'modname':modname})

            result = {'stack':stack_summary,
                      'frame_stack_len':frame_stack_len,
                      'running':self._running and 1 or 0}
            if exc_type:
                result['exc_type'] = exc_type
            if exc_value:
                result['exc_value'] = exc_value
            return result
        finally:
            frame = None
            stack = None

    def getBreakpointStats(self):
        rval = []
        for bps in bdb.Breakpoint.bplist.values():
            for bp in bps:
                filename = bp.file  # Already canonic
                rval.append({'filename':filename,
                             'lineno':bp.line,
                             'cond':bp.cond or '',
                             'temporary':bp.temporary and 1 or 0,
                             'enabled':bp.enabled and 1 or 0,
                             'hits':bp.hits or 0,
                             'ignore':bp.ignore or 0,
                             })
        return rval

    def getStatusSummary(self):
        rval = self.getExtendedFrameInfo()
        rval['breaks'] = self.getBreakpointStats()
        return rval

    def getSafeDict(self, locals, frameno):
        if locals:
            rname = 'locals'
        else:
            rname = 'globals'
        frame = self.getFrameByNumber(frameno)
        if frame is None:
            return {'frameno':frameno, rname:{}}
        globalsDict, localsDict = self.getFrameNamespaces(frame)
        if locals:
            d = self.safeReprDict(localsDict)
        else:
            d = self.safeReprDict(globalsDict)
        return {'frameno':frameno, rname:d}

    def evaluateWatches(self, exprs, frameno):
        frame = self.getFrameByNumber(frameno)
        if frame is None:
            return {'frameno':frameno, 'watches':{}}
        globalsDict, localsDict = self.getFrameNamespaces(frame)
        rval = {}
        for info in exprs:
            name = info['name']
            local = info['local']
            if local:
                primaryDict = localsDict
            else:
                primaryDict = globalsDict
            if primaryDict.has_key(name):
                value = primaryDict[name]
            else:
                try:
                    value = eval(name, globalsDict, localsDict)
                except Exception, message:
                    value = '??? (%s)' % message
            svalue = self.safeRepr(value)
            rval[name] = svalue
        return {'frameno':frameno, 'watches':rval}

    def getWatchSubobjects(self, expr, frameno):
        """Returns a tuple containing the names of subobjects
        available through the given watch expression."""
        frame = self.getFrameByNumber(frameno)
        if frame is None:
            return []
        globalsDict, localsDict = self.getFrameNamespaces(frame)
        try: inst_items = dir(eval(expr, globalsDict, localsDict))
        except: inst_items = []
        try: clss_items = dir(eval(expr, globalsDict, localsDict)
                              .__class__)
        except: clss_items = []
        return inst_items + clss_items

    def pythonShell(self, code, globalsDict, localsDict, name='<debug>'):
        from StringIO import StringIO

        _ts, sys.stdout = sys.stdout, StringIO('')
        try:
            co = compile(code, name, 'single')
            exec co in globalsDict, localsDict
            return sys.stdout.getvalue()
# lame attempt at handling None values
##            res = sys.stdout.getvalue()
##            if not res:
##                try:
##                    if eval(co, globalsDict, localsDict) is None:
##                        return 'None'
##                except:
##                    pass
##            return res
                    
        finally:
            sys.stdout = _ts

    def pprintVarValue(self, expr, frameno):
        frame = self.getFrameByNumber(frameno)
        if frame is None:
            return 'error: no current frame'
        else:
            try:
                globalsDict, localsDict = self.getFrameNamespaces(frame)
                return self.pythonShell(expr, globalsDict, localsDict)
            except:
                t, v = sys.exc_info()[:2]
                import traceback
                return ''.join(traceback.format_exception_only(t, v))

    def safeRepr(self, s):
        return self.repr.repr(s)

    def safeReprDict(self, dict):
        rval = {}
        l = dict.items()
        if len(l) >= self.maxdict2:
            l = l[:self.maxdict2]
        for key, value in l:
            rval[str(key)] = self.safeRepr(value)
        return rval

##    def updateBottomOfStackCodeObject(self, code):
##        frame = self.getFrameByNumber(-1)
##        if frame is not None:
##            frame.f_lineno = lineno
##            self.quitting = 0
##        else:
##            raise DebugError('No current frame')