cpython/Lib/pdb.py

450 lines
10 KiB
Python
Executable File

# pdb.py -- finally, a Python debugger!
# See file pdb.doc for instructions.
# To do:
# - It should be possible to intercept KeyboardInterrupt
# - Handle return events differently -- always printing the r.v. can be bad!
# - Merge with tb, to get a single debugger for active and post-mortem usage
# - Solve bugs in termination (e.g., 'continue' after the program
# is done proceeds to debug the debugger; 'quit' sometimes complains
# about the PdbQuit exception...)
import string
import sys
import linecache
from cmd import Cmd
# A specialization of Cmd for use by the debugger
PdbQuit = 'pdb.PdbQuit' # Exception to give up
class Pdb(Cmd):
def init(self):
self = Cmd.init(self)
self.prompt = '(Pdb) '
self.reset()
return self
def reset(self):
self.quitting = 0
self.breaks = {}
self.botframe = None
self.stopframe = None
self.lastretval = None
self.forget()
def forget(self):
self.setup(None, None)
def setup(self, f, t):
self.lineno = None
self.stack = []
self.curindex = 0
self.curframe = None
if f is None and t is None:
return
if t and t.tb_frame is f:
t = t.tb_next
while f is not None:
self.stack.append((f, f.f_lineno))
if f is self.botframe:
break
f = f.f_back
else:
print '[Weird: bottom frame not in stack trace.]'
self.stack.reverse()
self.curindex = max(0, len(self.stack) - 1)
while t is not None:
self.stack.append((t.tb_frame, t.tb_lineno))
t = t.tb_next
self.curframe = self.stack[self.curindex][0]
def run(self, cmd):
import __main__
dict = __main__.__dict__
self.runctx(cmd, dict, dict)
def runctx(self, cmd, globals, locals):
t = None
self.reset()
sys.trace = self.dispatch
try:
exec(cmd + '\n', globals, locals)
except PdbQuit:
return
except:
print '***', sys.exc_type + ':', `sys.exc_value`
t = sys.exc_traceback
finally:
self.trace = None
del self.trace
self.forget()
print '!!! Post-mortem debugging'
self.pmd(t)
def pmd(self, traceback):
t = traceback
if self.botframe is not None:
while t is not None:
if t.tb_frame is not self.botframe:
break
t = t.tb_next
else:
t = sys.exc_traceback
try:
self.ask_user(self.botframe, t)
except PdbQuit:
pass
finally:
self.forget()
def 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 '*** dispatch: unknown event type', `event`
return self.dispatch
def dispatch_line(self, frame):
if self.stop_here(frame) or self.break_here(frame):
self.ask_user(frame, None)
return self.dispatch
def dispatch_call(self, frame, arg):
if self.botframe is None:
# First call dispatch since reset()
self.botframe = frame
return None
if not (self.stop_here(frame) or self.break_anywhere(frame)):
return None
if arg is None:
print '[Entering non-function block.]'
else:
frame.f_locals['__args__'] = arg
return self.dispatch
def dispatch_return(self, frame, arg):
self.lastretval = arg
return None
def dispatch_exception(self, frame, arg):
if self.stop_here(frame):
print '!!!', arg[0] + ':', `arg[1]`
self.ask_user(frame, arg[2])
return self.dispatch
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):
if not self.breaks.has_key(frame.f_code.co_filename):
return 0
if not frame.f_lineno in \
self.breaks[frame.f_code.co_filename]:
return 0
return 1
def break_anywhere(self, frame):
return self.breaks.has_key(frame.f_code.co_filename)
def ask_user(self, frame, traceback):
self.setup(frame, traceback)
self.printframelineno(self.stack[self.curindex])
self.cmdloop()
self.forget()
def default(self, line):
if not line:
return self.do_next('')
else:
if line[0] == '!': line = line[1:]
try:
exec(line + '\n', \
self.curframe.f_globals, \
self.curframe.f_locals)
except:
print '***', sys.exc_type + ':',
print `sys.exc_value`
do_h = Cmd.do_help
def do_break(self, arg):
if not arg:
print self.breaks # XXX
return
try:
lineno = int(eval(arg))
except:
print '*** Error in argument:', `arg`
return
filename = self.curframe.f_code.co_filename
line = linecache.getline(filename, lineno)
if not line:
print '*** That line does not exist!'
return
if not self.breaks.has_key(filename):
self.breaks[filename] = []
list = self.breaks[filename]
if lineno in list:
print '*** There is already a break there!'
return
list.append(lineno)
do_b = do_break
def do_clear(self, arg):
if not arg:
try:
reply = raw_input('Clear all breaks? ')
except EOFError:
reply = 'no'
reply = string.lower(string.strip(reply))
if reply in ('y', 'yes'):
self.breaks = {}
return
try:
lineno = int(eval(arg))
except:
print '*** Error in argument:', `arg`
return
filename = self.curframe.f_code.co_filename
try:
self.breaks[filename].remove(lineno)
except (ValueError, KeyError):
print '*** There is no break there!'
return
if not self.breaks[filename]:
del self.breaks[filename]
do_cl = do_clear # 'c' is already an abbreviation for 'continue'
def do_where(self, arg):
self.printstacktrace()
do_w = do_where
def do_up(self, arg):
if self.curindex == 0:
print '*** Oldest frame'
else:
self.curindex = self.curindex - 1
self.curframe = self.stack[self.curindex][0]
self.printframelineno(self.stack[self.curindex])
do_u = do_up
def do_down(self, arg):
if self.curindex + 1 == len(self.stack):
print '*** Newest frame'
else:
self.curindex = self.curindex + 1
self.curframe = self.stack[self.curindex][0]
self.printframelineno(self.stack[self.curindex])
do_d = do_down
def do_step(self, arg):
self.stopframe = None
return 1
do_s = do_step
def do_next(self, arg):
self.stopframe = self.curframe
return 1
do_n = do_next
def do_return(self, arg):
self.stopframe = self.curframe.f_back
return 1
do_r = do_return
def do_retval(self, arg):
print self.lastretval
do_rv = do_retval
def do_continue(self, arg):
self.stopframe = self.botframe
return 1
do_c = do_cont = do_continue
def do_quit(self, arg):
self.quitting = 1
sys.trace = None; del sys.trace
raise PdbQuit
do_q = do_quit
def do_list(self, arg):
self.lastcmd = 'list'
last = None
if arg:
try:
x = eval(arg, {}, {})
if type(x) == type(()):
first, last = x
first = int(first)
last = int(last)
if last < first:
# Assume it's a count
last = first + last
else:
first = int(x)
except:
print '*** Error in argument:', `arg`
return
elif self.lineno is None:
first = max(1, self.curframe.f_lineno - 5)
else:
first = self.lineno + 1
if last is None:
last = first + 10
filename = self.curframe.f_code.co_filename
if self.breaks.has_key(filename):
breaklist = self.breaks[filename]
else:
breaklist = []
try:
for lineno in range(first, last+1):
line = linecache.getline(filename, lineno)
if not line:
print '[EOF]'
break
else:
s = string.rjust(`lineno`, 3)
if len(s) < 4: s = s + ' '
if lineno in breaklist: s = s + 'B'
else: s = s + ' '
if lineno == self.curframe.f_lineno:
s = s + '->'
print s + '\t' + line,
self.lineno = lineno
except KeyboardInterrupt:
pass
do_l = do_list
def do_args(self, arg):
try:
value = eval('__args__', self.curframe.f_globals, \
self.curframe.f_locals)
except:
print '***', sys.exc_type + ':', `sys.exc_value`
return
print `value`
do_a = do_args
def do_p(self, arg):
try:
value = eval(arg, self.curframe.f_globals, \
self.curframe.f_locals)
except:
print '***', sys.exc_type + ':', `sys.exc_value`
return
print `value`
# Print a traceback starting at the top stack frame.
# Note that the most recently entered frame is printed last;
# this is different from dbx and gdb, but consistent with
# the Python interpreter's stack trace.
# It is also consistent with the up/down commands (which are
# compatible with dbx and gdb: up moves towards 'main()'
# and down moves towards the most recent stack frame).
def printstacktrace(self):
for x in self.stack:
self.printframelineno(x)
def printframelineno(self, (frame, lineno)):
if frame is self.curframe: print '->',
code = frame.f_code
filename = code.co_filename
print filename + '(' + `lineno` + ')',
line = linecache.getline(filename, lineno)
print string.strip(line),
print
def run(statement):
Pdb().init().run(statement)
def runctx(statement, globals, locals):
Pdb().init().runctx(statement, globals, locals)
# --------------------- testing ---------------------
# The Ackermann function -- a highly recursive beast
cheat = 2
cache = {}
def ack(x, y):
key = `(long(x), long(y))`
if cache.has_key(key):
res = cache[key]
else:
if x == 0:
res = 1L
elif y == 0:
if x == 1:
res = 2L
else:
res = 2L + x
elif y == 1 and cheat >= 1:
res = 2L * x
elif y == 2 and cheat >= 2:
res = pow(2L, x)
else:
res = ack(ack(x-1, y), y-1)
cache[key] = res
return res
def foo(n):
print 'foo', n
x = bar(n*2)
print 'bar returned', x
y = ack(4, 3)
return y
def bar(a):
print 'bar', a
return a*10
def melt(n):
print 1.0/n
melt(n-1)
def test():
linecache.checkcache()
runctx('from pdb import foo; foo(12)', {}, {})
runctx('from pdb import melt; melt(5)', {}, {})
# --------------------- main ---------------------
import os
def main():
if sys.argv[1:]:
file = sys.argv[1]
head, tail = os.path.split(file)
if tail[-3:] != '.py':
print 'Sorry, file arg must be a python module'
print '(i.e., must end in \'.py\')'
# XXX Or we could copy it to a temp file
sys.exit(2)
del sys.argv[0]
sys.path.insert(0, head)
run('import ' + tail[:-3])
else:
run(raw_input('Python statement to debug: '))