1 """Debugger basics""" 2 3 import fnmatch 4 import sys 5 import os 6 import types 7 8 __all__ = ["BdbQuit","Bdb","Breakpoint"] 9 10 class BdbQuit(Exception): 11 """Exception to give up completely""" 12 13 14 class Bdb: 15 16 """Generic Python debugger base class. 17 18 This class takes care of details of the trace facility; 19 a derived class should implement user interaction. 20 The standard debugger class (pdb.Pdb) is an example. 21 """ 22 23 def __init__(self, skip=None): 24 self.skip = set(skip) if skip else None 25 self.breaks = {} 26 self.fncache = {} 27 28 def canonic(self, filename): 29 if filename == "<" + filename[1:-1] + ">": 30 return filename 31 canonic = self.fncache.get(filename) 32 if not canonic: 33 canonic = os.path.abspath(filename) 34 canonic = os.path.normcase(canonic) 35 self.fncache[filename] = canonic 36 return canonic 37 38 def reset(self): 39 import linecache 40 linecache.checkcache() 41 self.botframe = None 42 self._set_stopinfo(None, None) 43 44 def trace_dispatch(self, frame, event, arg): 45 if self.quitting: 46 return # None 47 if event == 'line': 48 return self.dispatch_line(frame) 49 if event == 'call': 50 return self.dispatch_call(frame, arg) 51 if event == 'return': 52 return self.dispatch_return(frame, arg) 53 if event == 'exception': 54 return self.dispatch_exception(frame, arg) 55 if event == 'c_call': 56 return self.trace_dispatch 57 if event == 'c_exception': 58 return self.trace_dispatch 59 if event == 'c_return': 60 return self.trace_dispatch 61 print 'bdb.Bdb.dispatch: unknown debugging event:', repr(event) 62 return self.trace_dispatch 63 64 def dispatch_line(self, frame): 65 if self.stop_here(frame) or self.break_here(frame): 66 self.user_line(frame) 67 if self.quitting: raise BdbQuit 68 return self.trace_dispatch 69 70 def dispatch_call(self, frame, arg): 71 # XXX 'arg' is no longer used 72 if self.botframe is None: 73 # First call of dispatch since reset() 74 self.botframe = frame.f_back # (CT) Note that this may also be None! 75 return self.trace_dispatch 76 if not (self.stop_here(frame) or self.break_anywhere(frame)): 77 # No need to trace this function 78 return # None 79 self.user_call(frame, arg) 80 if self.quitting: raise BdbQuit 81 return self.trace_dispatch 82 83 def dispatch_return(self, frame, arg): 84 if self.stop_here(frame) or frame == self.returnframe: 85 self.user_return(frame, arg) 86 if self.quitting: raise BdbQuit 87 return self.trace_dispatch 88 89 def dispatch_exception(self, frame, arg): 90 if self.stop_here(frame): 91 self.user_exception(frame, arg) 92 if self.quitting: raise BdbQuit 93 return self.trace_dispatch 94 95 # Normally derived classes don't override the following 96 # methods, but they may if they want to redefine the 97 # definition of stopping and breakpoints. 98 99 def is_skipped_module(self, module_name): 100 for pattern in self.skip: 101 if fnmatch.fnmatch(module_name, pattern): 102 return True 103 return False 104 105 def stop_here(self, frame): 106 # (CT) stopframe may now also be None, see dispatch_call. 107 # (CT) the former test for None is therefore removed from here. 108 if self.skip and \ 109 self.is_skipped_module(frame.f_globals.get('__name__')): 110 return False 111 if frame is self.stopframe: 112 if self.stoplineno == -1: 113 return False 114 return frame.f_lineno >= self.stoplineno 115 while frame is not None and frame is not self.stopframe: 116 if frame is self.botframe: 117 return True 118 frame = frame.f_back 119 return False 120 121 def break_here(self, frame): 122 filename = self.canonic(frame.f_code.co_filename) 123 if not filename in self.breaks: 124 return False 125 lineno = frame.f_lineno 126 if not lineno in self.breaks[filename]: 127 # The line itself has no breakpoint, but maybe the line is the 128 # first line of a function with breakpoint set by function name. 129 lineno = frame.f_code.co_firstlineno 130 if not lineno in self.breaks[filename]: 131 return False 132 133 # flag says ok to delete temp. bp 134 (bp, flag) = effective(filename, lineno, frame) 135 if bp: 136 self.currentbp = bp.number 137 if (flag and bp.temporary): 138 self.do_clear(str(bp.number)) 139 return True 140 else: 141 return False 142 143 def do_clear(self, arg): 144 raise NotImplementedError, "subclass of bdb must implement do_clear()" 145 146 def break_anywhere(self, frame): 147 return self.canonic(frame.f_code.co_filename) in self.breaks 148 149 # Derived classes should override the user_* methods 150 # to gain control. 151 152 def user_call(self, frame, argument_list): 153 """This method is called when there is the remote possibility 154 that we ever need to stop in this function.""" 155 pass 156 157 def user_line(self, frame): 158 """This method is called when we stop or break at this line.""" 159 pass 160 161 def user_return(self, frame, return_value): 162 """This method is called when a return trap is set here.""" 163 pass 164 165 def user_exception(self, frame, exc_info): 166 exc_type, exc_value, exc_traceback = exc_info 167 """This method is called if an exception occurs, 168 but only if we are to stop at or just below this level.""" 169 pass 170 171 def _set_stopinfo(self, stopframe, returnframe, stoplineno=0): 172 self.stopframe = stopframe 173 self.returnframe = returnframe 174 self.quitting = 0 175 # stoplineno >= 0 means: stop at line >= the stoplineno 176 # stoplineno -1 means: don't stop at all 177 self.stoplineno = stoplineno 178 179 # Derived classes and clients can call the following methods 180 # to affect the stepping state. 181 182 def set_until(self, frame): #the name "until" is borrowed from gdb 183 """Stop when the line with the line no greater than the current one is 184 reached or when returning from current frame""" 185 self._set_stopinfo(frame, frame, frame.f_lineno+1) 186 187 def set_step(self): 188 """Stop after one line of code.""" 189 self._set_stopinfo(None, None) 190 191 def set_next(self, frame): 192 """Stop on the next line in or below the given frame.""" 193 self._set_stopinfo(frame, None) 194 195 def set_return(self, frame): 196 """Stop when returning from the given frame.""" 197 self._set_stopinfo(frame.f_back, frame) 198 199 def set_trace(self, frame=None): 200 """Start debugging from `frame`. 201 202 If frame is not specified, debugging starts from caller's frame. 203 """ 204 if frame is None: 205 frame = sys._getframe().f_back 206 self.reset() 207 while frame: 208 frame.f_trace = self.trace_dispatch 209 self.botframe = frame 210 frame = frame.f_back 211 self.set_step() 212 sys.settrace(self.trace_dispatch) 213 214 def set_continue(self): 215 # Don't stop except at breakpoints or when finished 216 self._set_stopinfo(self.botframe, None, -1) 217 if not self.breaks: 218 # no breakpoints; run without debugger overhead 219 sys.settrace(None) 220 frame = sys._getframe().f_back 221 while frame and frame is not self.botframe: 222 del frame.f_trace 223 frame = frame.f_back 224 225 def set_quit(self): 226 self.stopframe = self.botframe 227 self.returnframe = None 228 self.quitting = 1 229 sys.settrace(None) 230 231 # Derived classes and clients can call the following methods 232 # to manipulate breakpoints. These methods return an 233 # error message is something went wrong, None if all is well. 234 # Set_break prints out the breakpoint line and file:lineno. 235 # Call self.get_*break*() to see the breakpoints or better 236 # for bp in Breakpoint.bpbynumber: if bp: bp.bpprint(). 237 238 def set_break(self, filename, lineno, temporary=0, cond = None, 239 funcname=None): 240 filename = self.canonic(filename) 241 import linecache # Import as late as possible 242 line = linecache.getline(filename, lineno) 243 if not line: 244 return 'Line %s:%d does not exist' % (filename, 245 lineno) 246 if not filename in self.breaks: 247 self.breaks[filename] = [] 248 list = self.breaks[filename] 249 if not lineno in list: 250 list.append(lineno) 251 bp = Breakpoint(filename, lineno, temporary, cond, funcname) 252 253 def _prune_breaks(self, filename, lineno): 254 if (filename, lineno) not in Breakpoint.bplist: 255 self.breaks[filename].remove(lineno) 256 if not self.breaks[filename]: 257 del self.breaks[filename] 258 259 def clear_break(self, filename, lineno): 260 filename = self.canonic(filename) 261 if not filename in self.breaks: 262 return 'There are no breakpoints in %s' % filename 263 if lineno not in self.breaks[filename]: 264 return 'There is no breakpoint at %s:%d' % (filename, 265 lineno) 266 # If there's only one bp in the list for that file,line 267 # pair, then remove the breaks entry 268 for bp in Breakpoint.bplist[filename, lineno][:]: 269 bp.deleteMe() 270 self._prune_breaks(filename, lineno) 271 272 def clear_bpbynumber(self, arg): 273 try: 274 number = int(arg) 275 except: 276 return 'Non-numeric breakpoint number (%s)' % arg 277 try: 278 bp = Breakpoint.bpbynumber[number] 279 except IndexError: 280 return 'Breakpoint number (%d) out of range' % number 281 if not bp: 282 return 'Breakpoint (%d) already deleted' % number 283 bp.deleteMe() 284 self._prune_breaks(bp.file, bp.line) 285 286 def clear_all_file_breaks(self, filename): 287 filename = self.canonic(filename) 288 if not filename in self.breaks: 289 return 'There are no breakpoints in %s' % filename 290 for line in self.breaks[filename]: 291 blist = Breakpoint.bplist[filename, line] 292 for bp in blist: 293 bp.deleteMe() 294 del self.breaks[filename] 295 296 def clear_all_breaks(self): 297 if not self.breaks: 298 return 'There are no breakpoints' 299 for bp in Breakpoint.bpbynumber: 300 if bp: 301 bp.deleteMe() 302 self.breaks = {} 303 304 def get_break(self, filename, lineno): 305 filename = self.canonic(filename) 306 return filename in self.breaks and \ 307 lineno in self.breaks[filename] 308 309 def get_breaks(self, filename, lineno): 310 filename = self.canonic(filename) 311 return filename in self.breaks and \ 312 lineno in self.breaks[filename] and \ 313 Breakpoint.bplist[filename, lineno] or [] 314 315 def get_file_breaks(self, filename): 316 filename = self.canonic(filename) 317 if filename in self.breaks: 318 return self.breaks[filename] 319 else: 320 return [] 321 322 def get_all_breaks(self): 323 return self.breaks 324 325 # Derived classes and clients can call the following method 326 # to get a data structure representing a stack trace. 327 328 def get_stack(self, f, t): 329 stack = [] 330 if t and t.tb_frame is f: 331 t = t.tb_next 332 while f is not None: 333 stack.append((f, f.f_lineno)) 334 if f is self.botframe: 335 break 336 f = f.f_back 337 stack.reverse() 338 i = max(0, len(stack) - 1) 339 while t is not None: 340 stack.append((t.tb_frame, t.tb_lineno)) 341 t = t.tb_next 342 if f is None: 343 i = max(0, len(stack) - 1) 344 return stack, i 345 346 # 347 348 def format_stack_entry(self, frame_lineno, lprefix=': '): 349 import linecache, repr 350 frame, lineno = frame_lineno 351 filename = self.canonic(frame.f_code.co_filename) 352 s = '%s(%r)' % (filename, lineno) 353 if frame.f_code.co_name: 354 s = s + frame.f_code.co_name 355 else: 356 s = s + "<lambda>" 357 if '__args__' in frame.f_locals: 358 args = frame.f_locals['__args__'] 359 else: 360 args = None 361 if args: 362 s = s + repr.repr(args) 363 else: 364 s = s + '()' 365 if '__return__' in frame.f_locals: 366 rv = frame.f_locals['__return__'] 367 s = s + '->' 368 s = s + repr.repr(rv) 369 line = linecache.getline(filename, lineno, frame.f_globals) 370 if line: s = s + lprefix + line.strip() 371 return s 372 373 # The following two methods can be called by clients to use 374 # a debugger to debug a statement, given as a string. 375 376 def run(self, cmd, globals=None, locals=None): 377 if globals is None: 378 import __main__ 379 globals = __main__.__dict__ 380 if locals is None: 381 locals = globals 382 self.reset() 383 sys.settrace(self.trace_dispatch) 384 if not isinstance(cmd, types.CodeType): 385 cmd = cmd+'\n' 386 try: 387 exec cmd in globals, locals 388 except BdbQuit: 389 pass 390 finally: 391 self.quitting = 1 392 sys.settrace(None) 393 394 def runeval(self, expr, globals=None, locals=None): 395 if globals is None: 396 import __main__ 397 globals = __main__.__dict__ 398 if locals is None: 399 locals = globals 400 self.reset() 401 sys.settrace(self.trace_dispatch) 402 if not isinstance(expr, types.CodeType): 403 expr = expr+'\n' 404 try: 405 return eval(expr, globals, locals) 406 except BdbQuit: 407 pass 408 finally: 409 self.quitting = 1 410 sys.settrace(None) 411 412 def runctx(self, cmd, globals, locals): 413 # B/W compatibility 414 self.run(cmd, globals, locals) 415 416 # This method is more useful to debug a single function call. 417 418 def runcall(self, func, *args, **kwds): 419 self.reset() 420 sys.settrace(self.trace_dispatch) 421 res = None 422 try: 423 res = func(*args, **kwds) 424 except BdbQuit: 425 pass 426 finally: 427 self.quitting = 1 428 sys.settrace(None) 429 return res 430 431 432 def set_trace(): 433 Bdb().set_trace() 434 435 436 class Breakpoint: 437 438 """Breakpoint class 439 440 Implements temporary breakpoints, ignore counts, disabling and 441 (re)-enabling, and conditionals. 442 443 Breakpoints are indexed by number through bpbynumber and by 444 the file,line tuple using bplist. The former points to a 445 single instance of class Breakpoint. The latter points to a 446 list of such instances since there may be more than one 447 breakpoint per line. 448 449 """ 450 451 # XXX Keeping state in the class is a mistake -- this means 452 # you cannot have more than one active Bdb instance. 453 454 next = 1 # Next bp to be assigned 455 bplist = {} # indexed by (file, lineno) tuple 456 bpbynumber = [None] # Each entry is None or an instance of Bpt 457 # index 0 is unused, except for marking an 458 # effective break .... see effective() 459 460 def __init__(self, file, line, temporary=0, cond=None, funcname=None): 461 self.funcname = funcname 462 # Needed if funcname is not None. 463 self.func_first_executable_line = None 464 self.file = file # This better be in canonical form! 465 self.line = line 466 self.temporary = temporary 467 self.cond = cond 468 self.enabled = 1 469 self.ignore = 0 470 self.hits = 0 471 self.number = Breakpoint.next 472 Breakpoint.next = Breakpoint.next + 1 473 # Build the two lists 474 self.bpbynumber.append(self) 475 if (file, line) in self.bplist: 476 self.bplist[file, line].append(self) 477 else: 478 self.bplist[file, line] = [self] 479 480 481 def deleteMe(self): 482 index = (self.file, self.line) 483 self.bpbynumber[self.number] = None # No longer in list 484 self.bplist[index].remove(self) 485 if not self.bplist[index]: 486 # No more bp for this f:l combo 487 del self.bplist[index] 488 489 def enable(self): 490 self.enabled = 1 491 492 def disable(self): 493 self.enabled = 0 494 495 def bpprint(self, out=None): 496 if out is None: 497 out = sys.stdout 498 if self.temporary: 499 disp = 'del ' 500 else: 501 disp = 'keep ' 502 if self.enabled: 503 disp = disp + 'yes ' 504 else: 505 disp = disp + 'no ' 506 print >>out, '%-4dbreakpoint %s at %s:%d' % (self.number, disp, 507 self.file, self.line) 508 if self.cond: 509 print >>out, '\tstop only if %s' % (self.cond,) 510 if self.ignore: 511 print >>out, '\tignore next %d hits' % (self.ignore) 512 if (self.hits): 513 if (self.hits > 1): ss = 's' 514 else: ss = '' 515 print >>out, ('\tbreakpoint already hit %d time%s' % 516 (self.hits, ss)) 517 518 # -----------end of Breakpoint class---------- 519 520 def checkfuncname(b, frame): 521 """Check whether we should break here because of `b.funcname`.""" 522 if not b.funcname: 523 # Breakpoint was set via line number. 524 if b.line != frame.f_lineno: 525 # Breakpoint was set at a line with a def statement and the function 526 # defined is called: don't break. 527 return False 528 return True 529 530 # Breakpoint set via function name. 531 532 if frame.f_code.co_name != b.funcname: 533 # It's not a function call, but rather execution of def statement. 534 return False 535 536 # We are in the right frame. 537 if not b.func_first_executable_line: 538 # The function is entered for the 1st time. 539 b.func_first_executable_line = frame.f_lineno 540 541 if b.func_first_executable_line != frame.f_lineno: 542 # But we are not at the first line number: don't break. 543 return False 544 return True 545 546 # Determines if there is an effective (active) breakpoint at this 547 # line of code. Returns breakpoint number or 0 if none 548 def effective(file, line, frame): 549 """Determine which breakpoint for this file:line is to be acted upon. 550 551 Called only if we know there is a bpt at this 552 location. Returns breakpoint that was triggered and a flag 553 that indicates if it is ok to delete a temporary bp. 554 555 """ 556 possibles = Breakpoint.bplist[file,line] 557 for i in range(0, len(possibles)): 558 b = possibles[i] 559 if b.enabled == 0: 560 continue 561 if not checkfuncname(b, frame): 562 continue 563 # Count every hit when bp is enabled 564 b.hits = b.hits + 1 565 if not b.cond: 566 # If unconditional, and ignoring, 567 # go on to next, else break 568 if b.ignore > 0: 569 b.ignore = b.ignore -1 570 continue 571 else: 572 # breakpoint and marker that's ok 573 # to delete if temporary 574 return (b,1) 575 else: 576 # Conditional bp. 577 # Ignore count applies only to those bpt hits where the 578 # condition evaluates to true. 579 try: 580 val = eval(b.cond, frame.f_globals, 581 frame.f_locals) 582 if val: 583 if b.ignore > 0: 584 b.ignore = b.ignore -1 585 # continue 586 else: 587 return (b,1) 588 # else: 589 # continue 590 except: 591 # if eval fails, most conservative 592 # thing is to stop on breakpoint 593 # regardless of ignore count. 594 # Don't delete temporary, 595 # as another hint to user. 596 return (b,0) 597 return (None, None) 598 599 # -------------------- testing -------------------- 600 601 class Tdb(Bdb): 602 def user_call(self, frame, args): 603 name = frame.f_code.co_name 604 if not name: name = '???' 605 print '+++ call', name, args 606 def user_line(self, frame): 607 import linecache 608 name = frame.f_code.co_name 609 if not name: name = '???' 610 fn = self.canonic(frame.f_code.co_filename) 611 line = linecache.getline(fn, frame.f_lineno, frame.f_globals) 612 print '+++', fn, frame.f_lineno, name, ':', line.strip() 613 def user_return(self, frame, retval): 614 print '+++ return', retval 615 def user_exception(self, frame, exc_stuff): 616 print '+++ exception', exc_stuff 617 self.set_continue() 618 619 def foo(n): 620 print 'foo(', n, ')' 621 x = bar(n*10) 622 print 'bar returned', x 623 624 def bar(a): 625 print 'bar(', a, ')' 626 return a/2 627 628 def test(): 629 t = Tdb() 630 t.run('import bdb; bdb.foo(10)') 631 632 # end 633
