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