Lib/bdb.py

   1 """Debugger basics"""
   2
   3 import sys
   4 import os
   5 import types
   6
   7 __all__ = ["BdbQuit","Bdb","Breakpoint"]
   8
   9 BdbQuit = 'bdb.BdbQuit' # Exception to give up completely
  10
  11
  12 class Bdb:
  13
  14     """Generic Python debugger base class.
  15
  16     This class takes care of details of the trace facility;
  17     a derived class should implement user interaction.
  18     The standard debugger class (pdb.Pdb) is an example.
  19     """
  20
  21     def __init__(self):
  22         self.breaks = {}
  23         self.fncache = {}
  24
  25     def canonic(self, filename):
  26         if filename == "<" + filename[1:-1] + ">":
  27             return filename
  28         canonic = self.fncache.get(filename)
  29         if not canonic:
  30             canonic = os.path.abspath(filename)
  31             self.fncache[filename] = canonic
  32         return canonic
  33
  34     def reset(self):
  35         import linecache
  36         linecache.checkcache()
  37         self.botframe = None
  38         self.stopframe = None
  39         self.returnframe = None
  40         self.quitting = 0
  41
  42     def trace_dispatch(self, frame, event, arg):
  43         if self.quitting:
  44             return # None
  45         if event == 'line':
  46             return self.dispatch_line(frame)
  47         if event == 'call':
  48             return self.dispatch_call(frame, arg)
  49         if event == 'return':
  50             return self.dispatch_return(frame, arg)
  51         if event == 'exception':
  52             return self.dispatch_exception(frame, arg)
  53         print 'bdb.Bdb.dispatch: unknown debugging event:', `event`
  54         return self.trace_dispatch
  55
  56     def dispatch_line(self, frame):
  57         if self.stop_here(frame) or self.break_here(frame):
  58             self.user_line(frame)
  59             if self.quitting: raise BdbQuit
  60         return self.trace_dispatch
  61
  62     def dispatch_call(self, frame, arg):
  63         # XXX 'arg' is no longer used
  64         if self.botframe is None:
  65             # First call of dispatch since reset()
  66             self.botframe = frame
  67             return self.trace_dispatch
  68         if not (self.stop_here(frame) or self.break_anywhere(frame)):
  69             # No need to trace this function
  70             return # None
  71         self.user_call(frame, arg)
  72         if self.quitting: raise BdbQuit
  73         return self.trace_dispatch
  74
  75     def dispatch_return(self, frame, arg):
  76         if self.stop_here(frame) or frame == self.returnframe:
  77             self.user_return(frame, arg)
  78             if self.quitting: raise BdbQuit
  79         return self.trace_dispatch
  80
  81     def dispatch_exception(self, frame, arg):
  82         if self.stop_here(frame):
  83             self.user_exception(frame, arg)
  84             if self.quitting: raise BdbQuit
  85         return self.trace_dispatch
  86
  87     # Normally derived classes don't override the following
  88     # methods, but they may if they want to redefine the
  89     # definition of stopping and breakpoints.
  90
  91     def stop_here(self, frame):
  92         if self.stopframe is None:
  93             return 1
  94         if frame is self.stopframe:
  95             return 1
  96         while frame is not None and frame is not self.stopframe:
  97             if frame is self.botframe:
  98                 return 1
  99             frame = frame.f_back
 100         return 0
 101
 102     def break_here(self, frame):
 103         filename = self.canonic(frame.f_code.co_filename)
 104         if not self.breaks.has_key(filename):
 105             return 0
 106         lineno = frame.f_lineno
 107         if not lineno in self.breaks[filename]:
 108             return 0
 109         # flag says ok to delete temp. bp
 110         (bp, flag) = effective(filename, lineno, frame)
 111         if bp:
 112             self.currentbp = bp.number
 113             if (flag and bp.temporary):
 114                 self.do_clear(str(bp.number))
 115             return 1
 116         else:
 117             return 0
 118
 119     def do_clear(self, arg):
 120         raise NotImplementedError, "subclass of bdb must implement do_clear()"
 121
 122     def break_anywhere(self, frame):
 123         return self.breaks.has_key(
 124             self.canonic(frame.f_code.co_filename))
 125
 126     # Derived classes should override the user_* methods
 127     # to gain control.
 128
 129     def user_call(self, frame, argument_list):
 130         """This method is called when there is the remote possibility
 131         that we ever need to stop in this function."""
 132         pass
 133
 134     def user_line(self, frame):
 135         """This method is called when we stop or break at this line."""
 136         pass
 137
 138     def user_return(self, frame, return_value):
 139         """This method is called when a return trap is set here."""
 140         pass
 141
 142     def user_exception(self, frame, (exc_type, exc_value, exc_traceback)):
 143         """This method is called if an exception occurs,
 144         but only if we are to stop at or just below this level."""
 145         pass
 146
 147     # Derived classes and clients can call the following methods
 148     # to affect the stepping state.
 149
 150     def set_step(self):
 151         """Stop after one line of code."""
 152         self.stopframe = None
 153         self.returnframe = None
 154         self.quitting = 0
 155
 156     def set_next(self, frame):
 157         """Stop on the next line in or below the given frame."""
 158         self.stopframe = frame
 159         self.returnframe = None
 160         self.quitting = 0
 161
 162     def set_return(self, frame):
 163         """Stop when returning from the given frame."""
 164         self.stopframe = frame.f_back
 165         self.returnframe = frame
 166         self.quitting = 0
 167
 168     def set_trace(self):
 169         """Start debugging from here."""
 170         try:
 171             1 + ''
 172         except:
 173             frame = sys.exc_info()[2].tb_frame.f_back
 174         self.reset()
 175         while frame:
 176             frame.f_trace = self.trace_dispatch
 177             self.botframe = frame
 178             frame = frame.f_back
 179         self.set_step()
 180         sys.settrace(self.trace_dispatch)
 181
 182     def set_continue(self):
 183         # Don't stop except at breakpoints or when finished
 184         self.stopframe = self.botframe
 185         self.returnframe = None
 186         self.quitting = 0
 187         if not self.breaks:
 188             # no breakpoints; run without debugger overhead
 189             sys.settrace(None)
 190             try:
 191                 1 + ''  # raise an exception
 192             except:
 193                 frame = sys.exc_info()[2].tb_frame.f_back
 194             while frame and frame is not self.botframe:
 195                 del frame.f_trace
 196                 frame = frame.f_back
 197
 198     def set_quit(self):
 199         self.stopframe = self.botframe
 200         self.returnframe = None
 201         self.quitting = 1
 202         sys.settrace(None)
 203
 204     # Derived classes and clients can call the following methods
 205     # to manipulate breakpoints.  These methods return an
 206     # error message is something went wrong, None if all is well.
 207     # Set_break prints out the breakpoint line and file:lineno.
 208     # Call self.get_*break*() to see the breakpoints or better
 209     # for bp in Breakpoint.bpbynumber: if bp: bp.bpprint().
 210
 211     def set_break(self, filename, lineno, temporary=0, cond = None):
 212         filename = self.canonic(filename)
 213         import linecache # Import as late as possible
 214         line = linecache.getline(filename, lineno)
 215         if not line:
 216             return 'Line %s:%d does not exist' % (filename,
 217                                    lineno)
 218         if not self.breaks.has_key(filename):
 219             self.breaks[filename] = []
 220         list = self.breaks[filename]
 221         if not lineno in list:
 222             list.append(lineno)
 223         bp = Breakpoint(filename, lineno, temporary, cond)
 224
 225     def clear_break(self, filename, lineno):
 226         filename = self.canonic(filename)
 227         if not self.breaks.has_key(filename):
 228             return 'There are no breakpoints in %s' % filename
 229         if lineno not in self.breaks[filename]:
 230             return 'There is no breakpoint at %s:%d' % (filename,
 231                                     lineno)
 232         # If there's only one bp in the list for that file,line
 233         # pair, then remove the breaks entry
 234         for bp in Breakpoint.bplist[filename, lineno][:]:
 235             bp.deleteMe()
 236         if not Breakpoint.bplist.has_key((filename, lineno)):
 237             self.breaks[filename].remove(lineno)
 238         if not self.breaks[filename]:
 239             del self.breaks[filename]
 240
 241     def clear_bpbynumber(self, arg):
 242         try:
 243             number = int(arg)
 244         except:
 245             return 'Non-numeric breakpoint number (%s)' % arg
 246         try:
 247             bp = Breakpoint.bpbynumber[number]
 248         except IndexError:
 249             return 'Breakpoint number (%d) out of range' % number
 250         if not bp:
 251             return 'Breakpoint (%d) already deleted' % number
 252         self.clear_break(bp.file, bp.line)
 253
 254     def clear_all_file_breaks(self, filename):
 255         filename = self.canonic(filename)
 256         if not self.breaks.has_key(filename):
 257             return 'There are no breakpoints in %s' % filename
 258         for line in self.breaks[filename]:
 259             blist = Breakpoint.bplist[filename, line]
 260             for bp in blist:
 261                 bp.deleteMe()
 262         del self.breaks[filename]
 263
 264     def clear_all_breaks(self):
 265         if not self.breaks:
 266             return 'There are no breakpoints'
 267         for bp in Breakpoint.bpbynumber:
 268             if bp:
 269                 bp.deleteMe()
 270         self.breaks = {}
 271
 272     def get_break(self, filename, lineno):
 273         filename = self.canonic(filename)
 274         return self.breaks.has_key(filename) and \
 275             lineno in self.breaks[filename]
 276
 277     def get_breaks(self, filename, lineno):
 278         filename = self.canonic(filename)
 279         return self.breaks.has_key(filename) and \
 280             lineno in self.breaks[filename] and \
 281             Breakpoint.bplist[filename, lineno] or []
 282
 283     def get_file_breaks(self, filename):
 284         filename = self.canonic(filename)
 285         if self.breaks.has_key(filename):
 286             return self.breaks[filename]
 287         else:
 288             return []
 289
 290     def get_all_breaks(self):
 291         return self.breaks
 292
 293     # Derived classes and clients can call the following method
 294     # to get a data structure representing a stack trace.
 295
 296     def get_stack(self, f, t):
 297         stack = []
 298         if t and t.tb_frame is f:
 299             t = t.tb_next
 300         while f is not None:
 301             stack.append((f, f.f_lineno))
 302             if f is self.botframe:
 303                 break
 304             f = f.f_back
 305         stack.reverse()
 306         i = max(0, len(stack) - 1)
 307         while t is not None:
 308             stack.append((t.tb_frame, t.tb_lineno))
 309             t = t.tb_next
 310         return stack, i
 311
 312     #
 313
 314     def format_stack_entry(self, frame_lineno, lprefix=': '):
 315         import linecache, repr
 316         frame, lineno = frame_lineno
 317         filename = self.canonic(frame.f_code.co_filename)
 318         s = filename + '(' + `lineno` + ')'
 319         if frame.f_code.co_name:
 320             s = s + frame.f_code.co_name
 321         else:
 322             s = s + "<lambda>"
 323         if frame.f_locals.has_key('__args__'):
 324             args = frame.f_locals['__args__']
 325         else:
 326             args = None
 327         if args:
 328             s = s + repr.repr(args)
 329         else:
 330             s = s + '()'
 331         if frame.f_locals.has_key('__return__'):
 332             rv = frame.f_locals['__return__']
 333             s = s + '->'
 334             s = s + repr.repr(rv)
 335         line = linecache.getline(filename, lineno)
 336         if line: s = s + lprefix + line.strip()
 337         return s
 338
 339     # The following two methods can be called by clients to use
 340     # a debugger to debug a statement, given as a string.
 341
 342     def run(self, cmd, globals=None, locals=None):
 343         if globals is None:
 344             import __main__
 345             globals = __main__.__dict__
 346         if locals is None:
 347             locals = globals
 348         self.reset()
 349         sys.settrace(self.trace_dispatch)
 350         if not isinstance(cmd, types.CodeType):
 351             cmd = cmd+'\n'
 352         try:
 353             try:
 354                 exec cmd in globals, locals
 355             except BdbQuit:
 356                 pass
 357         finally:
 358             self.quitting = 1
 359             sys.settrace(None)
 360
 361     def runeval(self, expr, globals=None, locals=None):
 362         if globals is None:
 363             import __main__
 364             globals = __main__.__dict__
 365         if locals is None:
 366             locals = globals
 367         self.reset()
 368         sys.settrace(self.trace_dispatch)
 369         if not isinstance(expr, types.CodeType):
 370             expr = expr+'\n'
 371         try:
 372             try:
 373                 return eval(expr, globals, locals)
 374             except BdbQuit:
 375                 pass
 376         finally:
 377             self.quitting = 1
 378             sys.settrace(None)
 379
 380     def runctx(self, cmd, globals, locals):
 381         # B/W compatibility
 382         self.run(cmd, globals, locals)
 383
 384     # This method is more useful to debug a single function call.
 385
 386     def runcall(self, func, *args):
 387         self.reset()
 388         sys.settrace(self.trace_dispatch)
 389         res = None
 390         try:
 391             try:
 392                 res = apply(func, args)
 393             except BdbQuit:
 394                 pass
 395         finally:
 396             self.quitting = 1
 397             sys.settrace(None)
 398         return res
 399
 400
 401 def set_trace():
 402     Bdb().set_trace()
 403
 404
 405 class Breakpoint:
 406
 407     """Breakpoint class
 408
 409     Implements temporary breakpoints, ignore counts, disabling and
 410     (re)-enabling, and conditionals.
 411
 412     Breakpoints are indexed by number through bpbynumber and by
 413     the file,line tuple using bplist.  The former points to a
 414     single instance of class Breakpoint.  The latter points to a
 415     list of such instances since there may be more than one
 416     breakpoint per line.
 417
 418     """
 419
 420     # XXX Keeping state in the class is a mistake -- this means
 421     # you cannot have more than one active Bdb instance.
 422
 423     next = 1        # Next bp to be assigned
 424     bplist = {}     # indexed by (file, lineno) tuple
 425     bpbynumber = [None] # Each entry is None or an instance of Bpt
 426                 # index 0 is unused, except for marking an
 427                 # effective break .... see effective()
 428
 429     def __init__(self, file, line, temporary=0, cond = None):
 430         self.file = file    # This better be in canonical form!
 431         self.line = line
 432         self.temporary = temporary
 433         self.cond = cond
 434         self.enabled = 1
 435         self.ignore = 0
 436         self.hits = 0
 437         self.number = Breakpoint.next
 438         Breakpoint.next = Breakpoint.next + 1
 439         # Build the two lists
 440         self.bpbynumber.append(self)
 441         if self.bplist.has_key((file, line)):
 442             self.bplist[file, line].append(self)
 443         else:
 444             self.bplist[file, line] = [self]
 445
 446
 447     def deleteMe(self):
 448         index = (self.file, self.line)
 449         self.bpbynumber[self.number] = None   # No longer in list
 450         self.bplist[index].remove(self)
 451         if not self.bplist[index]:
 452             # No more bp for this f:l combo
 453             del self.bplist[index]
 454
 455     def enable(self):
 456         self.enabled = 1
 457
 458     def disable(self):
 459         self.enabled = 0
 460
 461     def bpprint(self):
 462         if self.temporary:
 463             disp = 'del  '
 464         else:
 465             disp = 'keep '
 466         if self.enabled:
 467             disp = disp + 'yes'
 468         else:
 469             disp = disp + 'no '
 470         print '%-4dbreakpoint    %s at %s:%d' % (self.number, disp,
 471                              self.file, self.line)
 472         if self.cond:
 473             print '\tstop only if %s' % (self.cond,)
 474         if self.ignore:
 475             print '\tignore next %d hits' % (self.ignore)
 476         if (self.hits):
 477             if (self.hits > 1): ss = 's'
 478             else: ss = ''
 479             print ('\tbreakpoint already hit %d time%s' %
 480                    (self.hits, ss))
 481
 482 # -----------end of Breakpoint class----------
 483
 484 # Determines if there is an effective (active) breakpoint at this
 485 # line of code.  Returns breakpoint number or 0 if none
 486 def effective(file, line, frame):
 487     """Determine which breakpoint for this file:line is to be acted upon.
 488
 489     Called only if we know there is a bpt at this
 490     location.  Returns breakpoint that was triggered and a flag
 491     that indicates if it is ok to delete a temporary bp.
 492
 493     """
 494     possibles = Breakpoint.bplist[file,line]
 495     for i in range(0, len(possibles)):
 496         b = possibles[i]
 497         if b.enabled == 0:
 498             continue
 499         # Count every hit when bp is enabled
 500         b.hits = b.hits + 1
 501         if not b.cond:
 502             # If unconditional, and ignoring,
 503             # go on to next, else break
 504             if b.ignore > 0:
 505                 b.ignore = b.ignore -1
 506                 continue
 507             else:
 508                 # breakpoint and marker that's ok
 509                 # to delete if temporary
 510                 return (b,1)
 511         else:
 512             # Conditional bp.
 513             # Ignore count applies only to those bpt hits where the
 514             # condition evaluates to true.
 515             try:
 516                 val = eval(b.cond, frame.f_globals,
 517                        frame.f_locals)
 518                 if val:
 519                     if b.ignore > 0:
 520                         b.ignore = b.ignore -1
 521                         # continue
 522                     else:
 523                         return (b,1)
 524                 # else:
 525                 #   continue
 526             except:
 527                 # if eval fails, most conservative
 528                 # thing is to stop on breakpoint
 529                 # regardless of ignore count.
 530                 # Don't delete temporary,
 531                 # as another hint to user.
 532                 return (b,0)
 533     return (None, None)
 534
 535 # -------------------- testing --------------------
 536
 537 class Tdb(Bdb):
 538     def user_call(self, frame, args):
 539         name = frame.f_code.co_name
 540         if not name: name = '???'
 541         print '+++ call', name, args
 542     def user_line(self, frame):
 543         import linecache
 544         name = frame.f_code.co_name
 545         if not name: name = '???'
 546         fn = self.canonic(frame.f_code.co_filename)
 547         line = linecache.getline(fn, frame.f_lineno)
 548         print '+++', fn, frame.f_lineno, name, ':', line.strip()
 549     def user_return(self, frame, retval):
 550         print '+++ return', retval
 551     def user_exception(self, frame, exc_stuff):
 552         print '+++ exception', exc_stuff
 553         self.set_continue()
 554
 555 def foo(n):
 556     print 'foo(', n, ')'
 557     x = bar(n*10)
 558     print 'bar returned', x
 559
 560 def bar(a):
 561     print 'bar(', a, ')'
 562     return a/2
 563
 564 def test():
 565     t = Tdb()
 566     t.run('import bdb; bdb.foo(10)')
 567
 568 # end