1 # -*- coding: iso-8859-1 -*- 2 """Get useful information from live Python objects. 3 4 This module encapsulates the interface provided by the internal special 5 attributes (func_*, co_*, im_*, tb_*, etc.) in a friendlier fashion. 6 It also provides some help for examining source code and class layout. 7 8 Here are some of the useful functions provided by this module: 9 10 ismodule(), isclass(), ismethod(), isfunction(), isgeneratorfunction(), 11 isgenerator(), istraceback(), isframe(), iscode(), isbuiltin(), 12 isroutine() - check object types 13 getmembers() - get members of an object that satisfy a given condition 14 15 getfile(), getsourcefile(), getsource() - find an object's source code 16 getdoc(), getcomments() - get documentation on an object 17 getmodule() - determine the module that an object came from 18 getclasstree() - arrange classes so as to represent their hierarchy 19 20 getargspec(), getargvalues(), getcallargs() - get info about function arguments 21 formatargspec(), formatargvalues() - format an argument spec 22 getouterframes(), getinnerframes() - get info about frames 23 currentframe() - get the current stack frame 24 stack(), trace() - get info about frames on the stack or in a traceback 25 """ 26 27 # This module is in the public domain. No warranties. 28 29 __author__ = 'Ka-Ping Yee <ping (at] lfw.org>' 30 __date__ = '1 Jan 2001' 31 32 import sys 33 import os 34 import types 35 import string 36 import re 37 import dis 38 import imp 39 import tokenize 40 import linecache 41 from operator import attrgetter 42 from collections import namedtuple 43 44 # These constants are from Include/code.h. 45 CO_OPTIMIZED, CO_NEWLOCALS, CO_VARARGS, CO_VARKEYWORDS = 0x1, 0x2, 0x4, 0x8 46 CO_NESTED, CO_GENERATOR, CO_NOFREE = 0x10, 0x20, 0x40 47 # See Include/object.h 48 TPFLAGS_IS_ABSTRACT = 1 << 20 49 50 # ----------------------------------------------------------- type-checking 51 def ismodule(object): 52 """Return true if the object is a module. 53 54 Module objects provide these attributes: 55 __doc__ documentation string 56 __file__ filename (missing for built-in modules)""" 57 return isinstance(object, types.ModuleType) 58 59 def isclass(object): 60 """Return true if the object is a class. 61 62 Class objects provide these attributes: 63 __doc__ documentation string 64 __module__ name of module in which this class was defined""" 65 return isinstance(object, (type, types.ClassType)) 66 67 def ismethod(object): 68 """Return true if the object is an instance method. 69 70 Instance method objects provide these attributes: 71 __doc__ documentation string 72 __name__ name with which this method was defined 73 im_class class object in which this method belongs 74 im_func function object containing implementation of method 75 im_self instance to which this method is bound, or None""" 76 return isinstance(object, types.MethodType) 77 78 def ismethoddescriptor(object): 79 """Return true if the object is a method descriptor. 80 81 But not if ismethod() or isclass() or isfunction() are true. 82 83 This is new in Python 2.2, and, for example, is true of int.__add__. 84 An object passing this test has a __get__ attribute but not a __set__ 85 attribute, but beyond that the set of attributes varies. __name__ is 86 usually sensible, and __doc__ often is. 87 88 Methods implemented via descriptors that also pass one of the other 89 tests return false from the ismethoddescriptor() test, simply because 90 the other tests promise more -- you can, e.g., count on having the 91 im_func attribute (etc) when an object passes ismethod().""" 92 return (hasattr(object, "__get__") 93 and not hasattr(object, "__set__") # else it's a data descriptor 94 and not ismethod(object) # mutual exclusion 95 and not isfunction(object) 96 and not isclass(object)) 97 98 def isdatadescriptor(object): 99 """Return true if the object is a data descriptor. 100 101 Data descriptors have both a __get__ and a __set__ attribute. Examples are 102 properties (defined in Python) and getsets and members (defined in C). 103 Typically, data descriptors will also have __name__ and __doc__ attributes 104 (properties, getsets, and members have both of these attributes), but this 105 is not guaranteed.""" 106 return (hasattr(object, "__set__") and hasattr(object, "__get__")) 107 108 if hasattr(types, 'MemberDescriptorType'): 109 # CPython and equivalent 110 def ismemberdescriptor(object): 111 """Return true if the object is a member descriptor. 112 113 Member descriptors are specialized descriptors defined in extension 114 modules.""" 115 return isinstance(object, types.MemberDescriptorType) 116 else: 117 # Other implementations 118 def ismemberdescriptor(object): 119 """Return true if the object is a member descriptor. 120 121 Member descriptors are specialized descriptors defined in extension 122 modules.""" 123 return False 124 125 if hasattr(types, 'GetSetDescriptorType'): 126 # CPython and equivalent 127 def isgetsetdescriptor(object): 128 """Return true if the object is a getset descriptor. 129 130 getset descriptors are specialized descriptors defined in extension 131 modules.""" 132 return isinstance(object, types.GetSetDescriptorType) 133 else: 134 # Other implementations 135 def isgetsetdescriptor(object): 136 """Return true if the object is a getset descriptor. 137 138 getset descriptors are specialized descriptors defined in extension 139 modules.""" 140 return False 141 142 def isfunction(object): 143 """Return true if the object is a user-defined function. 144 145 Function objects provide these attributes: 146 __doc__ documentation string 147 __name__ name with which this function was defined 148 func_code code object containing compiled function bytecode 149 func_defaults tuple of any default values for arguments 150 func_doc (same as __doc__) 151 func_globals global namespace in which this function was defined 152 func_name (same as __name__)""" 153 return isinstance(object, types.FunctionType) 154 155 def isgeneratorfunction(object): 156 """Return true if the object is a user-defined generator function. 157 158 Generator function objects provide the same attributes as functions. 159 See help(isfunction) for a list of attributes.""" 160 return bool((isfunction(object) or ismethod(object)) and 161 object.func_code.co_flags & CO_GENERATOR) 162 163 def isgenerator(object): 164 """Return true if the object is a generator. 165 166 Generator objects provide these attributes: 167 __iter__ defined to support iteration over container 168 close raises a new GeneratorExit exception inside the 169 generator to terminate the iteration 170 gi_code code object 171 gi_frame frame object or possibly None once the generator has 172 been exhausted 173 gi_running set to 1 when generator is executing, 0 otherwise 174 next return the next item from the container 175 send resumes the generator and "sends" a value that becomes 176 the result of the current yield-expression 177 throw used to raise an exception inside the generator""" 178 return isinstance(object, types.GeneratorType) 179 180 def istraceback(object): 181 """Return true if the object is a traceback. 182 183 Traceback objects provide these attributes: 184 tb_frame frame object at this level 185 tb_lasti index of last attempted instruction in bytecode 186 tb_lineno current line number in Python source code 187 tb_next next inner traceback object (called by this level)""" 188 return isinstance(object, types.TracebackType) 189 190 def isframe(object): 191 """Return true if the object is a frame object. 192 193 Frame objects provide these attributes: 194 f_back next outer frame object (this frame's caller) 195 f_builtins built-in namespace seen by this frame 196 f_code code object being executed in this frame 197 f_exc_traceback traceback if raised in this frame, or None 198 f_exc_type exception type if raised in this frame, or None 199 f_exc_value exception value if raised in this frame, or None 200 f_globals global namespace seen by this frame 201 f_lasti index of last attempted instruction in bytecode 202 f_lineno current line number in Python source code 203 f_locals local namespace seen by this frame 204 f_restricted 0 or 1 if frame is in restricted execution mode 205 f_trace tracing function for this frame, or None""" 206 return isinstance(object, types.FrameType) 207 208 def iscode(object): 209 """Return true if the object is a code object. 210 211 Code objects provide these attributes: 212 co_argcount number of arguments (not including * or ** args) 213 co_code string of raw compiled bytecode 214 co_consts tuple of constants used in the bytecode 215 co_filename name of file in which this code object was created 216 co_firstlineno number of first line in Python source code 217 co_flags bitmap: 1=optimized | 2=newlocals | 4=*arg | 8=**arg 218 co_lnotab encoded mapping of line numbers to bytecode indices 219 co_name name with which this code object was defined 220 co_names tuple of names of local variables 221 co_nlocals number of local variables 222 co_stacksize virtual machine stack space required 223 co_varnames tuple of names of arguments and local variables""" 224 return isinstance(object, types.CodeType) 225 226 def isbuiltin(object): 227 """Return true if the object is a built-in function or method. 228 229 Built-in functions and methods provide these attributes: 230 __doc__ documentation string 231 __name__ original name of this function or method 232 __self__ instance to which a method is bound, or None""" 233 return isinstance(object, types.BuiltinFunctionType) 234 235 def isroutine(object): 236 """Return true if the object is any kind of function or method.""" 237 return (isbuiltin(object) 238 or isfunction(object) 239 or ismethod(object) 240 or ismethoddescriptor(object)) 241 242 def isabstract(object): 243 """Return true if the object is an abstract base class (ABC).""" 244 return bool(isinstance(object, type) and object.__flags__ & TPFLAGS_IS_ABSTRACT) 245 246 def getmembers(object, predicate=None): 247 """Return all members of an object as (name, value) pairs sorted by name. 248 Optionally, only return members that satisfy a given predicate.""" 249 results = [] 250 for key in dir(object): 251 try: 252 value = getattr(object, key) 253 except AttributeError: 254 continue 255 if not predicate or predicate(value): 256 results.append((key, value)) 257 results.sort() 258 return results 259 260 Attribute = namedtuple('Attribute', 'name kind defining_class object') 261 262 def classify_class_attrs(cls): 263 """Return list of attribute-descriptor tuples. 264 265 For each name in dir(cls), the return list contains a 4-tuple 266 with these elements: 267 268 0. The name (a string). 269 270 1. The kind of attribute this is, one of these strings: 271 'class method' created via classmethod() 272 'static method' created via staticmethod() 273 'property' created via property() 274 'method' any other flavor of method 275 'data' not a method 276 277 2. The class which defined this attribute (a class). 278 279 3. The object as obtained directly from the defining class's 280 __dict__, not via getattr. This is especially important for 281 data attributes: C.data is just a data object, but 282 C.__dict__['data'] may be a data descriptor with additional 283 info, like a __doc__ string. 284 """ 285 286 mro = getmro(cls) 287 names = dir(cls) 288 result = [] 289 for name in names: 290 # Get the object associated with the name, and where it was defined. 291 # Getting an obj from the __dict__ sometimes reveals more than 292 # using getattr. Static and class methods are dramatic examples. 293 # Furthermore, some objects may raise an Exception when fetched with 294 # getattr(). This is the case with some descriptors (bug #1785). 295 # Thus, we only use getattr() as a last resort. 296 homecls = None 297 for base in (cls,) + mro: 298 if name in base.__dict__: 299 obj = base.__dict__[name] 300 homecls = base 301 break 302 else: 303 obj = getattr(cls, name) 304 homecls = getattr(obj, "__objclass__", homecls) 305 306 # Classify the object. 307 if isinstance(obj, staticmethod): 308 kind = "static method" 309 elif isinstance(obj, classmethod): 310 kind = "class method" 311 elif isinstance(obj, property): 312 kind = "property" 313 elif ismethoddescriptor(obj): 314 kind = "method" 315 elif isdatadescriptor(obj): 316 kind = "data" 317 else: 318 obj_via_getattr = getattr(cls, name) 319 if (ismethod(obj_via_getattr) or 320 ismethoddescriptor(obj_via_getattr)): 321 kind = "method" 322 else: 323 kind = "data" 324 obj = obj_via_getattr 325 326 result.append(Attribute(name, kind, homecls, obj)) 327 328 return result 329 330 # ----------------------------------------------------------- class helpers 331 def _searchbases(cls, accum): 332 # Simulate the "classic class" search order. 333 if cls in accum: 334 return 335 accum.append(cls) 336 for base in cls.__bases__: 337 _searchbases(base, accum) 338 339 def getmro(cls): 340 "Return tuple of base classes (including cls) in method resolution order." 341 if hasattr(cls, "__mro__"): 342 return cls.__mro__ 343 else: 344 result = [] 345 _searchbases(cls, result) 346 return tuple(result) 347 348 # -------------------------------------------------- source code extraction 349 def indentsize(line): 350 """Return the indent size, in spaces, at the start of a line of text.""" 351 expline = string.expandtabs(line) 352 return len(expline) - len(string.lstrip(expline)) 353 354 def getdoc(object): 355 """Get the documentation string for an object. 356 357 All tabs are expanded to spaces. To clean up docstrings that are 358 indented to line up with blocks of code, any whitespace than can be 359 uniformly removed from the second line onwards is removed.""" 360 try: 361 doc = object.__doc__ 362 except AttributeError: 363 return None 364 if not isinstance(doc, types.StringTypes): 365 return None 366 return cleandoc(doc) 367 368 def cleandoc(doc): 369 """Clean up indentation from docstrings. 370 371 Any whitespace that can be uniformly removed from the second line 372 onwards is removed.""" 373 try: 374 lines = string.split(string.expandtabs(doc), '\n') 375 except UnicodeError: 376 return None 377 else: 378 # Find minimum indentation of any non-blank lines after first line. 379 margin = sys.maxint 380 for line in lines[1:]: 381 content = len(string.lstrip(line)) 382 if content: 383 indent = len(line) - content 384 margin = min(margin, indent) 385 # Remove indentation. 386 if lines: 387 lines[0] = lines[0].lstrip() 388 if margin < sys.maxint: 389 for i in range(1, len(lines)): lines[i] = lines[i][margin:] 390 # Remove any trailing or leading blank lines. 391 while lines and not lines[-1]: 392 lines.pop() 393 while lines and not lines[0]: 394 lines.pop(0) 395 return string.join(lines, '\n') 396 397 def getfile(object): 398 """Work out which source or compiled file an object was defined in.""" 399 if ismodule(object): 400 if hasattr(object, '__file__'): 401 return object.__file__ 402 raise TypeError('{!r} is a built-in module'.format(object)) 403 if isclass(object): 404 object = sys.modules.get(object.__module__) 405 if hasattr(object, '__file__'): 406 return object.__file__ 407 raise TypeError('{!r} is a built-in class'.format(object)) 408 if ismethod(object): 409 object = object.im_func 410 if isfunction(object): 411 object = object.func_code 412 if istraceback(object): 413 object = object.tb_frame 414 if isframe(object): 415 object = object.f_code 416 if iscode(object): 417 return object.co_filename 418 raise TypeError('{!r} is not a module, class, method, ' 419 'function, traceback, frame, or code object'.format(object)) 420 421 ModuleInfo = namedtuple('ModuleInfo', 'name suffix mode module_type') 422 423 def getmoduleinfo(path): 424 """Get the module name, suffix, mode, and module type for a given file.""" 425 filename = os.path.basename(path) 426 suffixes = map(lambda info: 427 (-len(info[0]), info[0], info[1], info[2]), 428 imp.get_suffixes()) 429 suffixes.sort() # try longest suffixes first, in case they overlap 430 for neglen, suffix, mode, mtype in suffixes: 431 if filename[neglen:] == suffix: 432 return ModuleInfo(filename[:neglen], suffix, mode, mtype) 433 434 def getmodulename(path): 435 """Return the module name for a given file, or None.""" 436 info = getmoduleinfo(path) 437 if info: return info[0] 438 439 def getsourcefile(object): 440 """Return the filename that can be used to locate an object's source. 441 Return None if no way can be identified to get the source. 442 """ 443 filename = getfile(object) 444 if string.lower(filename[-4:]) in ('.pyc', '.pyo'): 445 filename = filename[:-4] + '.py' 446 for suffix, mode, kind in imp.get_suffixes(): 447 if 'b' in mode and string.lower(filename[-len(suffix):]) == suffix: 448 # Looks like a binary file. We want to only return a text file. 449 return None 450 if os.path.exists(filename): 451 return filename 452 # only return a non-existent filename if the module has a PEP 302 loader 453 if hasattr(getmodule(object, filename), '__loader__'): 454 return filename 455 # or it is in the linecache 456 if filename in linecache.cache: 457 return filename 458 459 def getabsfile(object, _filename=None): 460 """Return an absolute path to the source or compiled file for an object. 461 462 The idea is for each object to have a unique origin, so this routine 463 normalizes the result as much as possible.""" 464 if _filename is None: 465 _filename = getsourcefile(object) or getfile(object) 466 return os.path.normcase(os.path.abspath(_filename)) 467 468 modulesbyfile = {} 469 _filesbymodname = {} 470 471 def getmodule(object, _filename=None): 472 """Return the module an object was defined in, or None if not found.""" 473 if ismodule(object): 474 return object 475 if hasattr(object, '__module__'): 476 return sys.modules.get(object.__module__) 477 # Try the filename to modulename cache 478 if _filename is not None and _filename in modulesbyfile: 479 return sys.modules.get(modulesbyfile[_filename]) 480 # Try the cache again with the absolute file name 481 try: 482 file = getabsfile(object, _filename) 483 except TypeError: 484 return None 485 if file in modulesbyfile: 486 return sys.modules.get(modulesbyfile[file]) 487 # Update the filename to module name cache and check yet again 488 # Copy sys.modules in order to cope with changes while iterating 489 for modname, module in sys.modules.items(): 490 if ismodule(module) and hasattr(module, '__file__'): 491 f = module.__file__ 492 if f == _filesbymodname.get(modname, None): 493 # Have already mapped this module, so skip it 494 continue 495 _filesbymodname[modname] = f 496 f = getabsfile(module) 497 # Always map to the name the module knows itself by 498 modulesbyfile[f] = modulesbyfile[ 499 os.path.realpath(f)] = module.__name__ 500 if file in modulesbyfile: 501 return sys.modules.get(modulesbyfile[file]) 502 # Check the main module 503 main = sys.modules['__main__'] 504 if not hasattr(object, '__name__'): 505 return None 506 if hasattr(main, object.__name__): 507 mainobject = getattr(main, object.__name__) 508 if mainobject is object: 509 return main 510 # Check builtins 511 builtin = sys.modules['__builtin__'] 512 if hasattr(builtin, object.__name__): 513 builtinobject = getattr(builtin, object.__name__) 514 if builtinobject is object: 515 return builtin 516 517 def findsource(object): 518 """Return the entire source file and starting line number for an object. 519 520 The argument may be a module, class, method, function, traceback, frame, 521 or code object. The source code is returned as a list of all the lines 522 in the file and the line number indexes a line in that list. An IOError 523 is raised if the source code cannot be retrieved.""" 524 525 file = getfile(object) 526 sourcefile = getsourcefile(object) 527 if not sourcefile and file[:1] + file[-1:] != '<>': 528 raise IOError('source code not available') 529 file = sourcefile if sourcefile else file 530 531 module = getmodule(object, file) 532 if module: 533 lines = linecache.getlines(file, module.__dict__) 534 else: 535 lines = linecache.getlines(file) 536 if not lines: 537 raise IOError('could not get source code') 538 539 if ismodule(object): 540 return lines, 0 541 542 if isclass(object): 543 name = object.__name__ 544 pat = re.compile(r'^(\s*)class\s*' + name + r'\b') 545 # make some effort to find the best matching class definition: 546 # use the one with the least indentation, which is the one 547 # that's most probably not inside a function definition. 548 candidates = [] 549 for i in range(len(lines)): 550 match = pat.match(lines[i]) 551 if match: 552 # if it's at toplevel, it's already the best one 553 if lines[i][0] == 'c': 554 return lines, i 555 # else add whitespace to candidate list 556 candidates.append((match.group(1), i)) 557 if candidates: 558 # this will sort by whitespace, and by line number, 559 # less whitespace first 560 candidates.sort() 561 return lines, candidates[0][1] 562 else: 563 raise IOError('could not find class definition') 564 565 if ismethod(object): 566 object = object.im_func 567 if isfunction(object): 568 object = object.func_code 569 if istraceback(object): 570 object = object.tb_frame 571 if isframe(object): 572 object = object.f_code 573 if iscode(object): 574 if not hasattr(object, 'co_firstlineno'): 575 raise IOError('could not find function definition') 576 lnum = object.co_firstlineno - 1 577 pat = re.compile(r'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)') 578 while lnum > 0: 579 if pat.match(lines[lnum]): break 580 lnum = lnum - 1 581 return lines, lnum 582 raise IOError('could not find code object') 583 584 def getcomments(object): 585 """Get lines of comments immediately preceding an object's source code. 586 587 Returns None when source can't be found. 588 """ 589 try: 590 lines, lnum = findsource(object) 591 except (IOError, TypeError): 592 return None 593 594 if ismodule(object): 595 # Look for a comment block at the top of the file. 596 start = 0 597 if lines and lines[0][:2] == '#!': start = 1 598 while start < len(lines) and string.strip(lines[start]) in ('', '#'): 599 start = start + 1 600 if start < len(lines) and lines[start][:1] == '#': 601 comments = [] 602 end = start 603 while end < len(lines) and lines[end][:1] == '#': 604 comments.append(string.expandtabs(lines[end])) 605 end = end + 1 606 return string.join(comments, '') 607 608 # Look for a preceding block of comments at the same indentation. 609 elif lnum > 0: 610 indent = indentsize(lines[lnum]) 611 end = lnum - 1 612 if end >= 0 and string.lstrip(lines[end])[:1] == '#' and \ 613 indentsize(lines[end]) == indent: 614 comments = [string.lstrip(string.expandtabs(lines[end]))] 615 if end > 0: 616 end = end - 1 617 comment = string.lstrip(string.expandtabs(lines[end])) 618 while comment[:1] == '#' and indentsize(lines[end]) == indent: 619 comments[:0] = [comment] 620 end = end - 1 621 if end < 0: break 622 comment = string.lstrip(string.expandtabs(lines[end])) 623 while comments and string.strip(comments[0]) == '#': 624 comments[:1] = [] 625 while comments and string.strip(comments[-1]) == '#': 626 comments[-1:] = [] 627 return string.join(comments, '') 628 629 class EndOfBlock(Exception): pass 630 631 class BlockFinder: 632 """Provide a tokeneater() method to detect the end of a code block.""" 633 def __init__(self): 634 self.indent = 0 635 self.islambda = False 636 self.started = False 637 self.passline = False 638 self.last = 1 639 640 def tokeneater(self, type, token, srow_scol, erow_ecol, line): 641 srow, scol = srow_scol 642 erow, ecol = erow_ecol 643 if not self.started: 644 # look for the first "def", "class" or "lambda" 645 if token in ("def", "class", "lambda"): 646 if token == "lambda": 647 self.islambda = True 648 self.started = True 649 self.passline = True # skip to the end of the line 650 elif type == tokenize.NEWLINE: 651 self.passline = False # stop skipping when a NEWLINE is seen 652 self.last = srow 653 if self.islambda: # lambdas always end at the first NEWLINE 654 raise EndOfBlock 655 elif self.passline: 656 pass 657 elif type == tokenize.INDENT: 658 self.indent = self.indent + 1 659 self.passline = True 660 elif type == tokenize.DEDENT: 661 self.indent = self.indent - 1 662 # the end of matching indent/dedent pairs end a block 663 # (note that this only works for "def"/"class" blocks, 664 # not e.g. for "if: else:" or "try: finally:" blocks) 665 if self.indent <= 0: 666 raise EndOfBlock 667 elif self.indent == 0 and type not in (tokenize.COMMENT, tokenize.NL): 668 # any other token on the same indentation level end the previous 669 # block as well, except the pseudo-tokens COMMENT and NL. 670 raise EndOfBlock 671 672 def getblock(lines): 673 """Extract the block of code at the top of the given list of lines.""" 674 blockfinder = BlockFinder() 675 try: 676 tokenize.tokenize(iter(lines).next, blockfinder.tokeneater) 677 except (EndOfBlock, IndentationError): 678 pass 679 return lines[:blockfinder.last] 680 681 def getsourcelines(object): 682 """Return a list of source lines and starting line number for an object. 683 684 The argument may be a module, class, method, function, traceback, frame, 685 or code object. The source code is returned as a list of the lines 686 corresponding to the object and the line number indicates where in the 687 original source file the first line of code was found. An IOError is 688 raised if the source code cannot be retrieved.""" 689 lines, lnum = findsource(object) 690 691 if ismodule(object): return lines, 0 692 else: return getblock(lines[lnum:]), lnum + 1 693 694 def getsource(object): 695 """Return the text of the source code for an object. 696 697 The argument may be a module, class, method, function, traceback, frame, 698 or code object. The source code is returned as a single string. An 699 IOError is raised if the source code cannot be retrieved.""" 700 lines, lnum = getsourcelines(object) 701 return string.join(lines, '') 702 703 # --------------------------------------------------- class tree extraction 704 def walktree(classes, children, parent): 705 """Recursive helper function for getclasstree().""" 706 results = [] 707 classes.sort(key=attrgetter('__module__', '__name__')) 708 for c in classes: 709 results.append((c, c.__bases__)) 710 if c in children: 711 results.append(walktree(children[c], children, c)) 712 return results 713 714 def getclasstree(classes, unique=0): 715 """Arrange the given list of classes into a hierarchy of nested lists. 716 717 Where a nested list appears, it contains classes derived from the class 718 whose entry immediately precedes the list. Each entry is a 2-tuple 719 containing a class and a tuple of its base classes. If the 'unique' 720 argument is true, exactly one entry appears in the returned structure 721 for each class in the given list. Otherwise, classes using multiple 722 inheritance and their descendants will appear multiple times.""" 723 children = {} 724 roots = [] 725 for c in classes: 726 if c.__bases__: 727 for parent in c.__bases__: 728 if not parent in children: 729 children[parent] = [] 730 if c not in children[parent]: 731 children[parent].append(c) 732 if unique and parent in classes: break 733 elif c not in roots: 734 roots.append(c) 735 for parent in children: 736 if parent not in classes: 737 roots.append(parent) 738 return walktree(roots, children, None) 739 740 # ------------------------------------------------ argument list extraction 741 Arguments = namedtuple('Arguments', 'args varargs keywords') 742 743 def getargs(co): 744 """Get information about the arguments accepted by a code object. 745 746 Three things are returned: (args, varargs, varkw), where 'args' is 747 a list of argument names (possibly containing nested lists), and 748 'varargs' and 'varkw' are the names of the * and ** arguments or None.""" 749 750 if not iscode(co): 751 raise TypeError('{!r} is not a code object'.format(co)) 752 753 nargs = co.co_argcount 754 names = co.co_varnames 755 args = list(names[:nargs]) 756 step = 0 757 758 # The following acrobatics are for anonymous (tuple) arguments. 759 for i in range(nargs): 760 if args[i][:1] in ('', '.'): 761 stack, remain, count = [], [], [] 762 while step < len(co.co_code): 763 op = ord(co.co_code[step]) 764 step = step + 1 765 if op >= dis.HAVE_ARGUMENT: 766 opname = dis.opname[op] 767 value = ord(co.co_code[step]) + ord(co.co_code[step+1])*256 768 step = step + 2 769 if opname in ('UNPACK_TUPLE', 'UNPACK_SEQUENCE'): 770 remain.append(value) 771 count.append(value) 772 elif opname == 'STORE_FAST': 773 stack.append(names[value]) 774 775 # Special case for sublists of length 1: def foo((bar)) 776 # doesn't generate the UNPACK_TUPLE bytecode, so if 777 # `remain` is empty here, we have such a sublist. 778 if not remain: 779 stack[0] = [stack[0]] 780 break 781 else: 782 remain[-1] = remain[-1] - 1 783 while remain[-1] == 0: 784 remain.pop() 785 size = count.pop() 786 stack[-size:] = [stack[-size:]] 787 if not remain: break 788 remain[-1] = remain[-1] - 1 789 if not remain: break 790 args[i] = stack[0] 791 792 varargs = None 793 if co.co_flags & CO_VARARGS: 794 varargs = co.co_varnames[nargs] 795 nargs = nargs + 1 796 varkw = None 797 if co.co_flags & CO_VARKEYWORDS: 798 varkw = co.co_varnames[nargs] 799 return Arguments(args, varargs, varkw) 800 801 ArgSpec = namedtuple('ArgSpec', 'args varargs keywords defaults') 802 803 def getargspec(func): 804 """Get the names and default values of a function's arguments. 805 806 A tuple of four things is returned: (args, varargs, varkw, defaults). 807 'args' is a list of the argument names (it may contain nested lists). 808 'varargs' and 'varkw' are the names of the * and ** arguments or None. 809 'defaults' is an n-tuple of the default values of the last n arguments. 810 """ 811 812 if ismethod(func): 813 func = func.im_func 814 if not isfunction(func): 815 raise TypeError('{!r} is not a Python function'.format(func)) 816 args, varargs, varkw = getargs(func.func_code) 817 return ArgSpec(args, varargs, varkw, func.func_defaults) 818 819 ArgInfo = namedtuple('ArgInfo', 'args varargs keywords locals') 820 821 def getargvalues(frame): 822 """Get information about arguments passed into a particular frame. 823 824 A tuple of four things is returned: (args, varargs, varkw, locals). 825 'args' is a list of the argument names (it may contain nested lists). 826 'varargs' and 'varkw' are the names of the * and ** arguments or None. 827 'locals' is the locals dictionary of the given frame.""" 828 args, varargs, varkw = getargs(frame.f_code) 829 return ArgInfo(args, varargs, varkw, frame.f_locals) 830 831 def joinseq(seq): 832 if len(seq) == 1: 833 return '(' + seq[0] + ',)' 834 else: 835 return '(' + string.join(seq, ', ') + ')' 836 837 def strseq(object, convert, join=joinseq): 838 """Recursively walk a sequence, stringifying each element.""" 839 if type(object) in (list, tuple): 840 return join(map(lambda o, c=convert, j=join: strseq(o, c, j), object)) 841 else: 842 return convert(object) 843 844 def formatargspec(args, varargs=None, varkw=None, defaults=None, 845 formatarg=str, 846 formatvarargs=lambda name: '*' + name, 847 formatvarkw=lambda name: '**' + name, 848 formatvalue=lambda value: '=' + repr(value), 849 join=joinseq): 850 """Format an argument spec from the 4 values returned by getargspec. 851 852 The first four arguments are (args, varargs, varkw, defaults). The 853 other four arguments are the corresponding optional formatting functions 854 that are called to turn names and values into strings. The ninth 855 argument is an optional function to format the sequence of arguments.""" 856 specs = [] 857 if defaults: 858 firstdefault = len(args) - len(defaults) 859 for i, arg in enumerate(args): 860 spec = strseq(arg, formatarg, join) 861 if defaults and i >= firstdefault: 862 spec = spec + formatvalue(defaults[i - firstdefault]) 863 specs.append(spec) 864 if varargs is not None: 865 specs.append(formatvarargs(varargs)) 866 if varkw is not None: 867 specs.append(formatvarkw(varkw)) 868 return '(' + string.join(specs, ', ') + ')' 869 870 def formatargvalues(args, varargs, varkw, locals, 871 formatarg=str, 872 formatvarargs=lambda name: '*' + name, 873 formatvarkw=lambda name: '**' + name, 874 formatvalue=lambda value: '=' + repr(value), 875 join=joinseq): 876 """Format an argument spec from the 4 values returned by getargvalues. 877 878 The first four arguments are (args, varargs, varkw, locals). The 879 next four arguments are the corresponding optional formatting functions 880 that are called to turn names and values into strings. The ninth 881 argument is an optional function to format the sequence of arguments.""" 882 def convert(name, locals=locals, 883 formatarg=formatarg, formatvalue=formatvalue): 884 return formatarg(name) + formatvalue(locals[name]) 885 specs = [] 886 for i in range(len(args)): 887 specs.append(strseq(args[i], convert, join)) 888 if varargs: 889 specs.append(formatvarargs(varargs) + formatvalue(locals[varargs])) 890 if varkw: 891 specs.append(formatvarkw(varkw) + formatvalue(locals[varkw])) 892 return '(' + string.join(specs, ', ') + ')' 893 894 def getcallargs(func, *positional, **named): 895 """Get the mapping of arguments to values. 896 897 A dict is returned, with keys the function argument names (including the 898 names of the * and ** arguments, if any), and values the respective bound 899 values from 'positional' and 'named'.""" 900 args, varargs, varkw, defaults = getargspec(func) 901 f_name = func.__name__ 902 arg2value = {} 903 904 # The following closures are basically because of tuple parameter unpacking. 905 assigned_tuple_params = [] 906 def assign(arg, value): 907 if isinstance(arg, str): 908 arg2value[arg] = value 909 else: 910 assigned_tuple_params.append(arg) 911 value = iter(value) 912 for i, subarg in enumerate(arg): 913 try: 914 subvalue = next(value) 915 except StopIteration: 916 raise ValueError('need more than %d %s to unpack' % 917 (i, 'values' if i > 1 else 'value')) 918 assign(subarg,subvalue) 919 try: 920 next(value) 921 except StopIteration: 922 pass 923 else: 924 raise ValueError('too many values to unpack') 925 def is_assigned(arg): 926 if isinstance(arg,str): 927 return arg in arg2value 928 return arg in assigned_tuple_params 929 if ismethod(func) and func.im_self is not None: 930 # implicit 'self' (or 'cls' for classmethods) argument 931 positional = (func.im_self,) + positional 932 num_pos = len(positional) 933 num_total = num_pos + len(named) 934 num_args = len(args) 935 num_defaults = len(defaults) if defaults else 0 936 for arg, value in zip(args, positional): 937 assign(arg, value) 938 if varargs: 939 if num_pos > num_args: 940 assign(varargs, positional[-(num_pos-num_args):]) 941 else: 942 assign(varargs, ()) 943 elif 0 < num_args < num_pos: 944 raise TypeError('%s() takes %s %d %s (%d given)' % ( 945 f_name, 'at most' if defaults else 'exactly', num_args, 946 'arguments' if num_args > 1 else 'argument', num_total)) 947 elif num_args == 0 and num_total: 948 if varkw: 949 if num_pos: 950 # XXX: We should use num_pos, but Python also uses num_total: 951 raise TypeError('%s() takes exactly 0 arguments ' 952 '(%d given)' % (f_name, num_total)) 953 else: 954 raise TypeError('%s() takes no arguments (%d given)' % 955 (f_name, num_total)) 956 for arg in args: 957 if isinstance(arg, str) and arg in named: 958 if is_assigned(arg): 959 raise TypeError("%s() got multiple values for keyword " 960 "argument '%s'" % (f_name, arg)) 961 else: 962 assign(arg, named.pop(arg)) 963 if defaults: # fill in any missing values with the defaults 964 for arg, value in zip(args[-num_defaults:], defaults): 965 if not is_assigned(arg): 966 assign(arg, value) 967 if varkw: 968 assign(varkw, named) 969 elif named: 970 unexpected = next(iter(named)) 971 try: 972 unicode 973 except NameError: 974 pass 975 else: 976 if isinstance(unexpected, unicode): 977 unexpected = unexpected.encode(sys.getdefaultencoding(), 'replace') 978 raise TypeError("%s() got an unexpected keyword argument '%s'" % 979 (f_name, unexpected)) 980 unassigned = num_args - len([arg for arg in args if is_assigned(arg)]) 981 if unassigned: 982 num_required = num_args - num_defaults 983 raise TypeError('%s() takes %s %d %s (%d given)' % ( 984 f_name, 'at least' if defaults else 'exactly', num_required, 985 'arguments' if num_required > 1 else 'argument', num_total)) 986 return arg2value 987 988 # -------------------------------------------------- stack frame extraction 989 990 Traceback = namedtuple('Traceback', 'filename lineno function code_context index') 991 992 def getframeinfo(frame, context=1): 993 """Get information about a frame or traceback object. 994 995 A tuple of five things is returned: the filename, the line number of 996 the current line, the function name, a list of lines of context from 997 the source code, and the index of the current line within that list. 998 The optional second argument specifies the number of lines of context 999 to return, which are centered around the current line.""" 1000 if istraceback(frame): 1001 lineno = frame.tb_lineno 1002 frame = frame.tb_frame 1003 else: 1004 lineno = frame.f_lineno 1005 if not isframe(frame): 1006 raise TypeError('{!r} is not a frame or traceback object'.format(frame)) 1007 1008 filename = getsourcefile(frame) or getfile(frame) 1009 if context > 0: 1010 start = lineno - 1 - context//2 1011 try: 1012 lines, lnum = findsource(frame) 1013 except IOError: 1014 lines = index = None 1015 else: 1016 start = max(start, 1) 1017 start = max(0, min(start, len(lines) - context)) 1018 lines = lines[start:start+context] 1019 index = lineno - 1 - start 1020 else: 1021 lines = index = None 1022 1023 return Traceback(filename, lineno, frame.f_code.co_name, lines, index) 1024 1025 def getlineno(frame): 1026 """Get the line number from a frame object, allowing for optimization.""" 1027 # FrameType.f_lineno is now a descriptor that grovels co_lnotab 1028 return frame.f_lineno 1029 1030 def getouterframes(frame, context=1): 1031 """Get a list of records for a frame and all higher (calling) frames. 1032 1033 Each record contains a frame object, filename, line number, function 1034 name, a list of lines of context, and index within the context.""" 1035 framelist = [] 1036 while frame: 1037 framelist.append((frame,) + getframeinfo(frame, context)) 1038 frame = frame.f_back 1039 return framelist 1040 1041 def getinnerframes(tb, context=1): 1042 """Get a list of records for a traceback's frame and all lower frames. 1043 1044 Each record contains a frame object, filename, line number, function 1045 name, a list of lines of context, and index within the context.""" 1046 framelist = [] 1047 while tb: 1048 framelist.append((tb.tb_frame,) + getframeinfo(tb, context)) 1049 tb = tb.tb_next 1050 return framelist 1051 1052 if hasattr(sys, '_getframe'): 1053 currentframe = sys._getframe 1054 else: 1055 currentframe = lambda _=None: None 1056 1057 def stack(context=1): 1058 """Return a list of records for the stack above the caller's frame.""" 1059 return getouterframes(sys._getframe(1), context) 1060 1061 def trace(context=1): 1062 """Return a list of records for the stack below the current exception.""" 1063 return getinnerframes(sys.exc_info()[2], context) 1064
