"""Debugger basics""" | |
import fnmatch | |
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, skip=None): | |
self.skip = set(skip) if skip else None | |
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 is_skipped_module(self, module_name): | |
for pattern in self.skip: | |
if fnmatch.fnmatch(module_name, pattern): | |
return True | |
return False | |
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 self.skip and \ | |
self.is_skipped_module(frame.f_globals.get('__name__')): | |
return False | |
if frame is self.stopframe: | |
if self.stoplineno == -1: | |
return False | |
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=0): | |
self.stopframe = stopframe | |
self.returnframe = returnframe | |
self.quitting = 0 | |
# stoplineno >= 0 means: stop at line >= the stoplineno | |
# stoplineno -1 means: don't stop at all | |
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, -1) | |
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 _prune_breaks(self, filename, lineno): | |
if (filename, lineno) not in Breakpoint.bplist: | |
self.breaks[filename].remove(lineno) | |
if not self.breaks[filename]: | |
del self.breaks[filename] | |
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() | |
self._prune_breaks(filename, lineno) | |
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 | |
bp.deleteMe() | |
self._prune_breaks(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, frame.f_globals) | |
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 (file, line) in self.bplist: | |
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): | |
"""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 | |
if not checkfuncname(b, frame): | |
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, frame.f_globals) | |
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 |