"""Debugger basics"""

import sys

import os

import types

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

BdbQuit = 'bdb.BdbQuit' # 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):

canonic = self.fncache.get(filename)

if not canonic:

canonic = os.path.abspath(filename)

self.fncache[filename] = canonic

return canonic

def reset(self):

import linecache

linecache.checkcache()

self.botframe = None

self.stopframe = None

self.returnframe = None

self.quitting = 0

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)

print 'bdb.Bdb.dispatch: unknown debugging event:', `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

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

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):

if self.stopframe is None:

return 1

if frame is self.stopframe:

return 1

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

if frame is self.botframe:

return 1

frame = frame.f_back

return 0

def break_here(self, frame):

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

if not self.breaks.has_key(filename):

return 0

lineno = frame.f_lineno

if not lineno in self.breaks[filename]:

return 0

# 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 1

else:

return 0

def break_anywhere(self, frame):

return self.breaks.has_key(

self.canonic(frame.f_code.co_filename))

# 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_type, exc_value, exc_traceback)):

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

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

pass

# Derived classes and clients can call the following methods

# to affect the stepping state.

def set_step(self):

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

self.stopframe = None

self.returnframe = None

self.quitting = 0

def set_next(self, frame):

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

self.stopframe = frame

self.returnframe = None

self.quitting = 0

def set_return(self, frame):

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

self.stopframe = frame.f_back

self.returnframe = frame

self.quitting = 0

def set_trace(self):

"""Start debugging from here."""

try:

1 + ''

except:

frame = sys.exc_info()[2].tb_frame.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.stopframe = self.botframe

self.returnframe = None

self.quitting = 0

if not self.breaks:

# no breakpoints; run without debugger overhead

sys.settrace(None)

try:

1 + '' # raise an exception

except:

frame = sys.exc_info()[2].tb_frame.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):

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 self.breaks.has_key(filename):

self.breaks[filename] = []

list = self.breaks[filename]

if not lineno in list:

list.append(lineno)

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

def clear_break(self, filename, lineno):

filename = self.canonic(filename)

if not self.breaks.has_key(filename):

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 self.breaks.has_key(filename):

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 self.breaks.has_key(filename) and \

lineno in self.breaks[filename]

def get_breaks(self, filename, lineno):

filename = self.canonic(filename)

return self.breaks.has_key(filename) and \

lineno in self.breaks[filename] and \

Breakpoint.bplist[filename, lineno] or []

def get_file_breaks(self, filename):

filename = self.canonic(filename)

if self.breaks.has_key(filename):

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

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 = filename + '(' + `lineno` + ')'

if frame.f_code.co_name:

s = s + frame.f_code.co_name

else:

s = s + "<lambda>"

if frame.f_locals.has_key('__args__'):

args = frame.f_locals['__args__']

else:

args = None

if args:

s = s + repr.repr(args)

else:

s = s + '()'

if frame.f_locals.has_key('__return__'):

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:

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:

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):

self.reset()

sys.settrace(self.trace_dispatch)

res = None

try:

try:

res = apply(func, args)

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):

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):

if self.temporary:

disp = 'del '

else:

disp = 'keep '

if self.enabled:

disp = disp + 'yes'

else:

disp = disp + 'no '

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

self.file, self.line)

if self.cond:

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

if self.ignore:

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

if (self.hits):

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

else: ss = ''

print ('\tbreakpoint already hit %d time%s' %

(self.hits, ss))

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

# 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):

"""Determine which breakpoint for this file:line is to be acted upon.

Called only if we know there is a bpt at this

location. Returns breakpoint that was triggered and a flag

that indicates if it is ok to delete a temporary bp.

"""

possibles = Breakpoint.bplist[file,line]

for i in range(0, len(possibles)):

b = possibles[i]

if b.enabled == 0:

continue

# Count every hit when bp is enabled

b.hits = b.hits + 1

if not b.cond:

# If unconditional, and ignoring,

# go on to next, else break

if b.ignore > 0:

b.ignore = b.ignore -1

continue

else:

# breakpoint and marker that's ok

# to delete if temporary

return (b,1)

else:

# Conditional bp.

# Ignore count applies only to those bpt hits where the

# condition evaluates to true.

try:

val = eval(b.cond, frame.f_globals,

frame.f_locals)

if val:

if b.ignore > 0:

b.ignore = b.ignore -1

# continue

else:

return (b,1)

# else:

# continue

except:

# if eval fails, most conservative

# thing is to stop on breakpoint

# regardless of ignore count.

# Don't delete temporary,

# as another hint to user.

return (b,0)

return (None, None)

# -------------------- testing --------------------

class Tdb(Bdb):

def user_call(self, frame, args):

name = frame.f_code.co_name

if not name: name = '???'

print '+++ call', name, args

def user_line(self, frame):

import linecache

name = frame.f_code.co_name

if not name: name = '???'

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

line = linecache.getline(fn, frame.f_lineno)

print '+++', fn, frame.f_lineno, name, ':', line.strip()

def user_return(self, frame, retval):

print '+++ return', retval

def user_exception(self, frame, exc_stuff):

print '+++ exception', exc_stuff

self.set_continue()

def foo(n):

print 'foo(', n, ')'

x = bar(n*10)

print 'bar returned', x

def bar(a):

print 'bar(', a, ')'

return a/2

def test():

t = Tdb()

t.run('import bdb; bdb.foo(10)')

# end