"""Debugger basics"""

import sys

import os

import types

__all__ = ["BdbQuit","Bdb","Breakpoint"]

class BdbQuit(Exception):

    """Exception to give up completely"""

class Bdb:

    """Generic Python debugger base class.

    This class takes care of details of the trace facility;

    a derived class should implement user interaction.

    The standard debugger class (pdb.Pdb) is an example.

    """

    def __init__(self):

        self.breaks = {}

        self.fncache = {}

    def canonic(self, filename):

        if filename == "<" + filename[1:-1] + ">":

            return filename

        canonic = self.fncache.get(filename)

        if not canonic:

            canonic = os.path.abspath(filename)

            canonic = os.path.normcase(canonic)

            self.fncache[filename] = canonic

        return canonic

    def reset(self):

        import linecache

        linecache.checkcache()

        self.botframe = None

        self._set_stopinfo(None, None)

    def trace_dispatch(self, frame, event, arg):

        if self.quitting:

            return # None

        if event == 'line':

            return self.dispatch_line(frame)

        if event == 'call':

            return self.dispatch_call(frame, arg)

        if event == 'return':

            return self.dispatch_return(frame, arg)

        if event == 'exception':

            return self.dispatch_exception(frame, arg)

        if event == 'c_call':

            return self.trace_dispatch

        if event == 'c_exception':

            return self.trace_dispatch

        if event == 'c_return':

            return self.trace_dispatch

        print 'bdb.Bdb.dispatch: unknown debugging event:', repr(event)

        return self.trace_dispatch

    def dispatch_line(self, frame):

        if self.stop_here(frame) or self.break_here(frame):

            self.user_line(frame)

            if self.quitting: raise BdbQuit

        return self.trace_dispatch

    def dispatch_call(self, frame, arg):

        # XXX 'arg' is no longer used

        if self.botframe is None:

            # First call of dispatch since reset()

            self.botframe = frame.f_back # (CT) Note that this may also be None!

            return self.trace_dispatch

        if not (self.stop_here(frame) or self.break_anywhere(frame)):

            # No need to trace this function

            return # None

        self.user_call(frame, arg)

        if self.quitting: raise BdbQuit

        return self.trace_dispatch

    def dispatch_return(self, frame, arg):

        if self.stop_here(frame) or frame == self.returnframe:

            self.user_return(frame, arg)

            if self.quitting: raise BdbQuit

        return self.trace_dispatch

    def dispatch_exception(self, frame, arg):

        if self.stop_here(frame):

            self.user_exception(frame, arg)

            if self.quitting: raise BdbQuit

        return self.trace_dispatch

    # Normally derived classes don't override the following

    # methods, but they may if they want to redefine the

    # definition of stopping and breakpoints.

    def stop_here(self, frame):

        # (CT) stopframe may now also be None, see dispatch_call.

        # (CT) the former test for None is therefore removed from here.

        if frame is self.stopframe:

            return frame.f_lineno >= self.stoplineno

        while frame is not None and frame is not self.stopframe:

            if frame is self.botframe:

                return True

            frame = frame.f_back

        return False

    def break_here(self, frame):

        filename = self.canonic(frame.f_code.co_filename)

        if not filename in self.breaks:

            return False

        lineno = frame.f_lineno

        if not lineno in self.breaks[filename]:

            # The line itself has no breakpoint, but maybe the line is the

            # first line of a function with breakpoint set by function name.

            lineno = frame.f_code.co_firstlineno

            if not lineno in self.breaks[filename]:

                return False

        # flag says ok to delete temp. bp

        (bp, flag) = effective(filename, lineno, frame)

        if bp:

            self.currentbp = bp.number

            if (flag and bp.temporary):

                self.do_clear(str(bp.number))

            return True

        else:

            return False

    def do_clear(self, arg):

        raise NotImplementedError, "subclass of bdb must implement do_clear()"

    def break_anywhere(self, frame):

        return self.canonic(frame.f_code.co_filename) in self.breaks

    # Derived classes should override the user_* methods

    # to gain control.

    def user_call(self, frame, argument_list):

        """This method is called when there is the remote possibility

        that we ever need to stop in this function."""

        pass

    def user_line(self, frame):

        """This method is called when we stop or break at this line."""

        pass

    def user_return(self, frame, return_value):

        """This method is called when a return trap is set here."""

        pass

    def user_exception(self, frame, exc_info):

        exc_type, exc_value, exc_traceback = exc_info

        """This method is called if an exception occurs,

        but only if we are to stop at or just below this level."""

        pass

    def _set_stopinfo(self, stopframe, returnframe, stoplineno=-1):

        self.stopframe = stopframe

        self.returnframe = returnframe

        self.quitting = 0

        self.stoplineno = stoplineno

    # Derived classes and clients can call the following methods

    # to affect the stepping state.

    def set_until(self, frame): #the name "until" is borrowed from gdb

        """Stop when the line with the line no greater than the current one is

        reached or when returning from current frame"""

        self._set_stopinfo(frame, frame, frame.f_lineno+1)

    def set_step(self):

        """Stop after one line of code."""

        self._set_stopinfo(None,None)

    def set_next(self, frame):

        """Stop on the next line in or below the given frame."""

        self._set_stopinfo(frame, None)

    def set_return(self, frame):

        """Stop when returning from the given frame."""

        self._set_stopinfo(frame.f_back, frame)

    def set_trace(self, frame=None):

        """Start debugging from `frame`.

        If frame is not specified, debugging starts from caller's frame.

        """

        if frame is None:

            frame = sys._getframe().f_back

        self.reset()

        while frame:

            frame.f_trace = self.trace_dispatch

            self.botframe = frame

            frame = frame.f_back

        self.set_step()

        sys.settrace(self.trace_dispatch)

    def set_continue(self):

        # Don't stop except at breakpoints or when finished

        self._set_stopinfo(self.botframe, None)

        if not self.breaks:

            # no breakpoints; run without debugger overhead

            sys.settrace(None)

            frame = sys._getframe().f_back

            while frame and frame is not self.botframe:

                del frame.f_trace

                frame = frame.f_back

    def set_quit(self):

        self.stopframe = self.botframe

        self.returnframe = None

        self.quitting = 1

        sys.settrace(None)

    # Derived classes and clients can call the following methods

    # to manipulate breakpoints.  These methods return an

    # error message is something went wrong, None if all is well.

    # Set_break prints out the breakpoint line and file:lineno.

    # Call self.get_*break*() to see the breakpoints or better

    # for bp in Breakpoint.bpbynumber: if bp: bp.bpprint().

    def set_break(self, filename, lineno, temporary=0, cond = None,

                  funcname=None):

        filename = self.canonic(filename)

        import linecache # Import as late as possible

        line = linecache.getline(filename, lineno)

        if not line:

            return 'Line %s:%d does not exist' % (filename,

                                   lineno)

        if not filename in self.breaks:

            self.breaks[filename] = []

        list = self.breaks[filename]

        if not lineno in list:

            list.append(lineno)

        bp = Breakpoint(filename, lineno, temporary, cond, funcname)

    def clear_break(self, filename, lineno):

        filename = self.canonic(filename)

        if not filename in self.breaks:

            return 'There are no breakpoints in %s' % filename

        if lineno not in self.breaks[filename]:

            return 'There is no breakpoint at %s:%d' % (filename,

                                    lineno)

        # If there's only one bp in the list for that file,line

        # pair, then remove the breaks entry

        for bp in Breakpoint.bplist[filename, lineno][:]:

            bp.deleteMe()

        if not Breakpoint.bplist.has_key((filename, lineno)):

            self.breaks[filename].remove(lineno)

        if not self.breaks[filename]:

            del self.breaks[filename]

    def clear_bpbynumber(self, arg):

        try:

            number = int(arg)

        except:

            return 'Non-numeric breakpoint number (%s)' % arg

        try:

            bp = Breakpoint.bpbynumber[number]

        except IndexError:

            return 'Breakpoint number (%d) out of range' % number

        if not bp:

            return 'Breakpoint (%d) already deleted' % number

        self.clear_break(bp.file, bp.line)

    def clear_all_file_breaks(self, filename):

        filename = self.canonic(filename)

        if not filename in self.breaks:

            return 'There are no breakpoints in %s' % filename

        for line in self.breaks[filename]:

            blist = Breakpoint.bplist[filename, line]

            for bp in blist:

                bp.deleteMe()

        del self.breaks[filename]

    def clear_all_breaks(self):

        if not self.breaks:

            return 'There are no breakpoints'

        for bp in Breakpoint.bpbynumber:

            if bp:

                bp.deleteMe()

        self.breaks = {}

    def get_break(self, filename, lineno):

        filename = self.canonic(filename)

        return filename in self.breaks and \

            lineno in self.breaks[filename]

    def get_breaks(self, filename, lineno):

        filename = self.canonic(filename)

        return filename in self.breaks and \

            lineno in self.breaks[filename] and \

            Breakpoint.bplist[filename, lineno] or []

    def get_file_breaks(self, filename):

        filename = self.canonic(filename)

        if filename in self.breaks:

            return self.breaks[filename]

        else:

            return []

    def get_all_breaks(self):

        return self.breaks

    # Derived classes and clients can call the following method

    # to get a data structure representing a stack trace.

    def get_stack(self, f, t):

        stack = []

        if t and t.tb_frame is f:

            t = t.tb_next

        while f is not None:

            stack.append((f, f.f_lineno))

            if f is self.botframe:

                break

            f = f.f_back

        stack.reverse()

        i = max(0, len(stack) - 1)

        while t is not None:

            stack.append((t.tb_frame, t.tb_lineno))

            t = t.tb_next

        if f is None:

            i = max(0, len(stack) - 1)

        return stack, i

    #

    def format_stack_entry(self, frame_lineno, lprefix=': '):

        import linecache, repr

        frame, lineno = frame_lineno

        filename = self.canonic(frame.f_code.co_filename)

        s = '%s(%r)' % (filename, lineno)

        if frame.f_code.co_name:

            s = s + frame.f_code.co_name

        else:

            s = s + "<lambda>"

        if '__args__' in frame.f_locals:

            args = frame.f_locals['__args__']

        else:

            args = None

        if args:

            s = s + repr.repr(args)

        else:

            s = s + '()'

        if '__return__' in frame.f_locals:

            rv = frame.f_locals['__return__']

            s = s + '->'

            s = s + repr.repr(rv)

        line = linecache.getline(filename, lineno)

        if line: s = s + lprefix + line.strip()

        return s

    # The following two methods can be called by clients to use

    # a debugger to debug a statement, given as a string.

    def run(self, cmd, globals=None, locals=None):

        if globals is None:

            import __main__

            globals = __main__.__dict__

        if locals is None:

            locals = globals

        self.reset()

        sys.settrace(self.trace_dispatch)

        if not isinstance(cmd, types.CodeType):

            cmd = cmd+'\n'

        try:

            exec cmd in globals, locals

        except BdbQuit:

            pass

        finally:

            self.quitting = 1

            sys.settrace(None)

    def runeval(self, expr, globals=None, locals=None):

        if globals is None:

            import __main__

            globals = __main__.__dict__

        if locals is None:

            locals = globals

        self.reset()

        sys.settrace(self.trace_dispatch)

        if not isinstance(expr, types.CodeType):

            expr = expr+'\n'

        try:

            return eval(expr, globals, locals)

        except BdbQuit:

            pass

        finally:

            self.quitting = 1

            sys.settrace(None)

    def runctx(self, cmd, globals, locals):

        # B/W compatibility

        self.run(cmd, globals, locals)

    # This method is more useful to debug a single function call.

    def runcall(self, func, *args, **kwds):

        self.reset()

        sys.settrace(self.trace_dispatch)

        res = None

        try:

            res = func(*args, **kwds)

        except BdbQuit:

            pass

        finally:

            self.quitting = 1

            sys.settrace(None)

        return res

def set_trace():

    Bdb().set_trace()

class Breakpoint:

    """Breakpoint class

    Implements temporary breakpoints, ignore counts, disabling and

    (re)-enabling, and conditionals.

    Breakpoints are indexed by number through bpbynumber and by

    the file,line tuple using bplist.  The former points to a

    single instance of class Breakpoint.  The latter points to a

    list of such instances since there may be more than one

    breakpoint per line.

    """

    # XXX Keeping state in the class is a mistake -- this means

    # you cannot have more than one active Bdb instance.

    next = 1        # Next bp to be assigned

    bplist = {}     # indexed by (file, lineno) tuple

    bpbynumber = [None] # Each entry is None or an instance of Bpt

                # index 0 is unused, except for marking an

                # effective break .... see effective()

    def __init__(self, file, line, temporary=0, cond=None, funcname=None):

        self.funcname = funcname

        # Needed if funcname is not None.

        self.func_first_executable_line = None

        self.file = file    # This better be in canonical form!

        self.line = line

        self.temporary = temporary

        self.cond = cond

        self.enabled = 1

        self.ignore = 0

        self.hits = 0

        self.number = Breakpoint.next

        Breakpoint.next = Breakpoint.next + 1

        # Build the two lists

        self.bpbynumber.append(self)

        if self.bplist.has_key((file, line)):

            self.bplist[file, line].append(self)

        else:

            self.bplist[file, line] = [self]

    def deleteMe(self):

        index = (self.file, self.line)

        self.bpbynumber[self.number] = None   # No longer in list

        self.bplist[index].remove(self)

        if not self.bplist[index]:

            # No more bp for this f:l combo

            del self.bplist[index]

    def enable(self):

        self.enabled = 1

    def disable(self):

        self.enabled = 0

    def bpprint(self, out=None):

        if out is None:

            out = sys.stdout

        if self.temporary:

            disp = 'del  '

        else:

            disp = 'keep '

        if self.enabled:

            disp = disp + 'yes  '

        else:

            disp = disp + 'no   '

        print >>out, '%-4dbreakpoint   %s at %s:%d' % (self.number, disp,

                                                       self.file, self.line)

        if self.cond:

            print >>out, '\tstop only if %s' % (self.cond,)

        if self.ignore:

            print >>out, '\tignore next %d hits' % (self.ignore)

        if (self.hits):

            if (self.hits > 1): ss = 's'

            else: ss = ''

            print >>out, ('\tbreakpoint already hit %d time%s' %

                          (self.hits, ss))

# -----------end of Breakpoint class----------

def checkfuncname(b, frame):

    """Check whether we should break here because of `b.funcname`."""

    if not b.funcname:

        # Breakpoint was set via line number.

        if b.line != frame.f_lineno:

            # Breakpoint was set at a line with a def statement and the function

            # defined is called: don't break.

            return False

        return True

    # Breakpoint set via function name.

    if frame.f_code.co_name != b.funcname:

        # It's not a function call, but rather execution of def statement.

        return False

    # We are in the right frame.

    if not b.func_first_executable_line:

        # The function is entered for the 1st time.

        b.func_first_executable_line = frame.f_lineno

    if  b.func_first_executable_line != frame.f_lineno:

        # But we are not at the first line number: don't break.

        return False

    return True

# Determines if there is an effective (active) breakpoint at this

# line of code.  Returns breakpoint number or 0 if none

def effective(file, line, frame):