1 # -*- coding: iso-8859-1 -*-
2 """Get useful information from live Python objects.
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.
8 Here are some of the useful functions provided by this module:
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
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
20 getargspec(), getargvalues() - 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
27 # This module is in the public domain. No warranties.
29 __author__
= 'Ka-Ping Yee <ping@lfw.org>'
30 __date__
= '1 Jan 2001'
41 from abc
import ABCMeta
42 from operator
import attrgetter
43 from collections
import namedtuple
45 # These constants are from Include/code.h.
46 CO_OPTIMIZED
, CO_NEWLOCALS
, CO_VARARGS
, CO_VARKEYWORDS
= 0x1, 0x2, 0x4, 0x8
47 CO_NESTED
, CO_GENERATOR
, CO_NOFREE
= 0x10, 0x20, 0x40
48 # See Include/object.h
49 TPFLAGS_IS_ABSTRACT
= 1 << 20
51 # ----------------------------------------------------------- type-checking
53 """Return true if the object is a module.
55 Module objects provide these attributes:
56 __doc__ documentation string
57 __file__ filename (missing for built-in modules)"""
58 return isinstance(object, types
.ModuleType
)
61 """Return true if the object is a class.
63 Class objects provide these attributes:
64 __doc__ documentation string
65 __module__ name of module in which this class was defined"""
66 return isinstance(object, types
.ClassType
) or hasattr(object, '__bases__')
69 """Return true if the object is an instance method.
71 Instance method objects provide these attributes:
72 __doc__ documentation string
73 __name__ name with which this method was defined
74 im_class class object in which this method belongs
75 im_func function object containing implementation of method
76 im_self instance to which this method is bound, or None"""
77 return isinstance(object, types
.MethodType
)
79 def ismethoddescriptor(object):
80 """Return true if the object is a method descriptor.
82 But not if ismethod() or isclass() or isfunction() are true.
84 This is new in Python 2.2, and, for example, is true of int.__add__.
85 An object passing this test has a __get__ attribute but not a __set__
86 attribute, but beyond that the set of attributes varies. __name__ is
87 usually sensible, and __doc__ often is.
89 Methods implemented via descriptors that also pass one of the other
90 tests return false from the ismethoddescriptor() test, simply because
91 the other tests promise more -- you can, e.g., count on having the
92 im_func attribute (etc) when an object passes ismethod()."""
93 return (hasattr(object, "__get__")
94 and not hasattr(object, "__set__") # else it's a data descriptor
95 and not ismethod(object) # mutual exclusion
96 and not isfunction(object)
97 and not isclass(object))
99 def isdatadescriptor(object):
100 """Return true if the object is a data descriptor.
102 Data descriptors have both a __get__ and a __set__ attribute. Examples are
103 properties (defined in Python) and getsets and members (defined in C).
104 Typically, data descriptors will also have __name__ and __doc__ attributes
105 (properties, getsets, and members have both of these attributes), but this
106 is not guaranteed."""
107 return (hasattr(object, "__set__") and hasattr(object, "__get__"))
109 if hasattr(types
, 'MemberDescriptorType'):
110 # CPython and equivalent
111 def ismemberdescriptor(object):
112 """Return true if the object is a member descriptor.
114 Member descriptors are specialized descriptors defined in extension
116 return isinstance(object, types
.MemberDescriptorType
)
118 # Other implementations
119 def ismemberdescriptor(object):
120 """Return true if the object is a member descriptor.
122 Member descriptors are specialized descriptors defined in extension
126 if hasattr(types
, 'GetSetDescriptorType'):
127 # CPython and equivalent
128 def isgetsetdescriptor(object):
129 """Return true if the object is a getset descriptor.
131 getset descriptors are specialized descriptors defined in extension
133 return isinstance(object, types
.GetSetDescriptorType
)
135 # Other implementations
136 def isgetsetdescriptor(object):
137 """Return true if the object is a getset descriptor.
139 getset descriptors are specialized descriptors defined in extension
143 def isfunction(object):
144 """Return true if the object is a user-defined function.
146 Function objects provide these attributes:
147 __doc__ documentation string
148 __name__ name with which this function was defined
149 func_code code object containing compiled function bytecode
150 func_defaults tuple of any default values for arguments
151 func_doc (same as __doc__)
152 func_globals global namespace in which this function was defined
153 func_name (same as __name__)"""
154 return isinstance(object, types
.FunctionType
)
156 def isgeneratorfunction(object):
157 """Return true if the object is a user-defined generator function.
159 Generator function objects provides same attributes as functions.
161 See isfunction.__doc__ for attributes listing."""
162 if (isfunction(object) or ismethod(object)) and \
163 object.func_code
.co_flags
& CO_GENERATOR
:
166 def isgenerator(object):
167 """Return true if the object is a generator.
169 Generator objects provide these attributes:
170 __iter__ defined to support interation over container
171 close raises a new GeneratorExit exception inside the
172 generator to terminate the iteration
174 gi_frame frame object or possibly None once the generator has
176 gi_running set to 1 when generator is executing, 0 otherwise
177 next return the next item from the container
178 send resumes the generator and "sends" a value that becomes
179 the result of the current yield-expression
180 throw used to raise an exception inside the generator"""
181 return isinstance(object, types
.GeneratorType
)
183 def istraceback(object):
184 """Return true if the object is a traceback.
186 Traceback objects provide these attributes:
187 tb_frame frame object at this level
188 tb_lasti index of last attempted instruction in bytecode
189 tb_lineno current line number in Python source code
190 tb_next next inner traceback object (called by this level)"""
191 return isinstance(object, types
.TracebackType
)
194 """Return true if the object is a frame object.
196 Frame objects provide these attributes:
197 f_back next outer frame object (this frame's caller)
198 f_builtins built-in namespace seen by this frame
199 f_code code object being executed in this frame
200 f_exc_traceback traceback if raised in this frame, or None
201 f_exc_type exception type if raised in this frame, or None
202 f_exc_value exception value if raised in this frame, or None
203 f_globals global namespace seen by this frame
204 f_lasti index of last attempted instruction in bytecode
205 f_lineno current line number in Python source code
206 f_locals local namespace seen by this frame
207 f_restricted 0 or 1 if frame is in restricted execution mode
208 f_trace tracing function for this frame, or None"""
209 return isinstance(object, types
.FrameType
)
212 """Return true if the object is a code object.
214 Code objects provide these attributes:
215 co_argcount number of arguments (not including * or ** args)
216 co_code string of raw compiled bytecode
217 co_consts tuple of constants used in the bytecode
218 co_filename name of file in which this code object was created
219 co_firstlineno number of first line in Python source code
220 co_flags bitmap: 1=optimized | 2=newlocals | 4=*arg | 8=**arg
221 co_lnotab encoded mapping of line numbers to bytecode indices
222 co_name name with which this code object was defined
223 co_names tuple of names of local variables
224 co_nlocals number of local variables
225 co_stacksize virtual machine stack space required
226 co_varnames tuple of names of arguments and local variables"""
227 return isinstance(object, types
.CodeType
)
229 def isbuiltin(object):
230 """Return true if the object is a built-in function or method.
232 Built-in functions and methods provide these attributes:
233 __doc__ documentation string
234 __name__ original name of this function or method
235 __self__ instance to which a method is bound, or None"""
236 return isinstance(object, types
.BuiltinFunctionType
)
238 def isroutine(object):
239 """Return true if the object is any kind of function or method."""
240 return (isbuiltin(object)
241 or isfunction(object)
243 or ismethoddescriptor(object))
245 def isgenerator(object):
246 """Return true if the object is a generator object."""
247 return isinstance(object, types
.GeneratorType
)
249 def isabstract(object):
250 """Return true if the object is an abstract base class (ABC)."""
251 return isinstance(object, type) and object.__flags
__ & TPFLAGS_IS_ABSTRACT
253 def getmembers(object, predicate
=None):
254 """Return all members of an object as (name, value) pairs sorted by name.
255 Optionally, only return members that satisfy a given predicate."""
257 for key
in dir(object):
258 value
= getattr(object, key
)
259 if not predicate
or predicate(value
):
260 results
.append((key
, value
))
264 Attribute
= namedtuple('Attribute', 'name kind defining_class object')
266 def classify_class_attrs(cls
):
267 """Return list of attribute-descriptor tuples.
269 For each name in dir(cls), the return list contains a 4-tuple
272 0. The name (a string).
274 1. The kind of attribute this is, one of these strings:
275 'class method' created via classmethod()
276 'static method' created via staticmethod()
277 'property' created via property()
278 'method' any other flavor of method
281 2. The class which defined this attribute (a class).
283 3. The object as obtained directly from the defining class's
284 __dict__, not via getattr. This is especially important for
285 data attributes: C.data is just a data object, but
286 C.__dict__['data'] may be a data descriptor with additional
287 info, like a __doc__ string.
294 # Get the object associated with the name.
295 # Getting an obj from the __dict__ sometimes reveals more than
296 # using getattr. Static and class methods are dramatic examples.
297 if name
in cls
.__dict
__:
298 obj
= cls
.__dict
__[name
]
300 obj
= getattr(cls
, name
)
302 # Figure out where it was defined.
303 homecls
= getattr(obj
, "__objclass__", None)
307 if name
in base
.__dict
__:
311 # Get the object again, in order to get it from the defining
312 # __dict__ instead of via getattr (if possible).
313 if homecls
is not None and name
in homecls
.__dict
__:
314 obj
= homecls
.__dict
__[name
]
316 # Also get the object via getattr.
317 obj_via_getattr
= getattr(cls
, name
)
319 # Classify the object.
320 if isinstance(obj
, staticmethod):
321 kind
= "static method"
322 elif isinstance(obj
, classmethod):
323 kind
= "class method"
324 elif isinstance(obj
, property):
326 elif (ismethod(obj_via_getattr
) or
327 ismethoddescriptor(obj_via_getattr
)):
332 result
.append(Attribute(name
, kind
, homecls
, obj
))
336 # ----------------------------------------------------------- class helpers
337 def _searchbases(cls
, accum
):
338 # Simulate the "classic class" search order.
342 for base
in cls
.__bases
__:
343 _searchbases(base
, accum
)
346 "Return tuple of base classes (including cls) in method resolution order."
347 if hasattr(cls
, "__mro__"):
351 _searchbases(cls
, result
)
354 # -------------------------------------------------- source code extraction
355 def indentsize(line
):
356 """Return the indent size, in spaces, at the start of a line of text."""
357 expline
= string
.expandtabs(line
)
358 return len(expline
) - len(string
.lstrip(expline
))
361 """Get the documentation string for an object.
363 All tabs are expanded to spaces. To clean up docstrings that are
364 indented to line up with blocks of code, any whitespace than can be
365 uniformly removed from the second line onwards is removed."""
368 except AttributeError:
370 if not isinstance(doc
, types
.StringTypes
):
375 """Clean up indentation from docstrings.
377 Any whitespace that can be uniformly removed from the second line
378 onwards is removed."""
380 lines
= string
.split(string
.expandtabs(doc
), '\n')
384 # Find minimum indentation of any non-blank lines after first line.
386 for line
in lines
[1:]:
387 content
= len(string
.lstrip(line
))
389 indent
= len(line
) - content
390 margin
= min(margin
, indent
)
391 # Remove indentation.
393 lines
[0] = lines
[0].lstrip()
394 if margin
< sys
.maxint
:
395 for i
in range(1, len(lines
)): lines
[i
] = lines
[i
][margin
:]
396 # Remove any trailing or leading blank lines.
397 while lines
and not lines
[-1]:
399 while lines
and not lines
[0]:
401 return string
.join(lines
, '\n')
404 """Work out which source or compiled file an object was defined in."""
406 if hasattr(object, '__file__'):
407 return object.__file
__
408 raise TypeError('arg is a built-in module')
410 object = sys
.modules
.get(object.__module
__)
411 if hasattr(object, '__file__'):
412 return object.__file
__
413 raise TypeError('arg is a built-in class')
415 object = object.im_func
416 if isfunction(object):
417 object = object.func_code
418 if istraceback(object):
419 object = object.tb_frame
421 object = object.f_code
423 return object.co_filename
424 raise TypeError('arg is not a module, class, method, '
425 'function, traceback, frame, or code object')
427 ModuleInfo
= namedtuple('ModuleInfo', 'name suffix mode module_type')
429 def getmoduleinfo(path
):
430 """Get the module name, suffix, mode, and module type for a given file."""
431 filename
= os
.path
.basename(path
)
432 suffixes
= map(lambda info
:
433 (-len(info
[0]), info
[0], info
[1], info
[2]),
435 suffixes
.sort() # try longest suffixes first, in case they overlap
436 for neglen
, suffix
, mode
, mtype
in suffixes
:
437 if filename
[neglen
:] == suffix
:
438 return ModuleInfo(filename
[:neglen
], suffix
, mode
, mtype
)
440 def getmodulename(path
):
441 """Return the module name for a given file, or None."""
442 info
= getmoduleinfo(path
)
443 if info
: return info
[0]
445 def getsourcefile(object):
446 """Return the Python source file an object was defined in, if it exists."""
447 filename
= getfile(object)
448 if string
.lower(filename
[-4:]) in ('.pyc', '.pyo'):
449 filename
= filename
[:-4] + '.py'
450 for suffix
, mode
, kind
in imp
.get_suffixes():
451 if 'b' in mode
and string
.lower(filename
[-len(suffix
):]) == suffix
:
452 # Looks like a binary file. We want to only return a text file.
454 if os
.path
.exists(filename
):
456 # only return a non-existent filename if the module has a PEP 302 loader
457 if hasattr(getmodule(object, filename
), '__loader__'):
460 def getabsfile(object, _filename
=None):
461 """Return an absolute path to the source or compiled file for an object.
463 The idea is for each object to have a unique origin, so this routine
464 normalizes the result as much as possible."""
465 if _filename
is None:
466 _filename
= getsourcefile(object) or getfile(object)
467 return os
.path
.normcase(os
.path
.abspath(_filename
))
472 def getmodule(object, _filename
=None):
473 """Return the module an object was defined in, or None if not found."""
476 if hasattr(object, '__module__'):
477 return sys
.modules
.get(object.__module
__)
478 # Try the filename to modulename cache
479 if _filename
is not None and _filename
in modulesbyfile
:
480 return sys
.modules
.get(modulesbyfile
[_filename
])
481 # Try the cache again with the absolute file name
483 file = getabsfile(object, _filename
)
486 if file in modulesbyfile
:
487 return sys
.modules
.get(modulesbyfile
[file])
488 # Update the filename to module name cache and check yet again
489 # Copy sys.modules in order to cope with changes while iterating
490 for modname
, module
in sys
.modules
.items():
491 if ismodule(module
) and hasattr(module
, '__file__'):
493 if f
== _filesbymodname
.get(modname
, None):
494 # Have already mapped this module, so skip it
496 _filesbymodname
[modname
] = f
497 f
= getabsfile(module
)
498 # Always map to the name the module knows itself by
499 modulesbyfile
[f
] = modulesbyfile
[
500 os
.path
.realpath(f
)] = module
.__name
__
501 if file in modulesbyfile
:
502 return sys
.modules
.get(modulesbyfile
[file])
503 # Check the main module
504 main
= sys
.modules
['__main__']
505 if not hasattr(object, '__name__'):
507 if hasattr(main
, object.__name
__):
508 mainobject
= getattr(main
, object.__name
__)
509 if mainobject
is object:
512 builtin
= sys
.modules
['__builtin__']
513 if hasattr(builtin
, object.__name
__):
514 builtinobject
= getattr(builtin
, object.__name
__)
515 if builtinobject
is object:
518 def findsource(object):
519 """Return the entire source file and starting line number for an object.
521 The argument may be a module, class, method, function, traceback, frame,
522 or code object. The source code is returned as a list of all the lines
523 in the file and the line number indexes a line in that list. An IOError
524 is raised if the source code cannot be retrieved."""
525 file = getsourcefile(object) or getfile(object)
526 module
= getmodule(object, file)
528 lines
= linecache
.getlines(file, module
.__dict
__)
530 lines
= linecache
.getlines(file)
532 raise IOError('could not get source code')
538 name
= object.__name
__
539 pat
= re
.compile(r
'^(\s*)class\s*' + name
+ r
'\b')
540 # make some effort to find the best matching class definition:
541 # use the one with the least indentation, which is the one
542 # that's most probably not inside a function definition.
544 for i
in range(len(lines
)):
545 match
= pat
.match(lines
[i
])
547 # if it's at toplevel, it's already the best one
548 if lines
[i
][0] == 'c':
550 # else add whitespace to candidate list
551 candidates
.append((match
.group(1), i
))
553 # this will sort by whitespace, and by line number,
554 # less whitespace first
556 return lines
, candidates
[0][1]
558 raise IOError('could not find class definition')
561 object = object.im_func
562 if isfunction(object):
563 object = object.func_code
564 if istraceback(object):
565 object = object.tb_frame
567 object = object.f_code
569 if not hasattr(object, 'co_firstlineno'):
570 raise IOError('could not find function definition')
571 lnum
= object.co_firstlineno
- 1
572 pat
= re
.compile(r
'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)')
574 if pat
.match(lines
[lnum
]): break
577 raise IOError('could not find code object')
579 def getcomments(object):
580 """Get lines of comments immediately preceding an object's source code.
582 Returns None when source can't be found.
585 lines
, lnum
= findsource(object)
586 except (IOError, TypeError):
590 # Look for a comment block at the top of the file.
592 if lines
and lines
[0][:2] == '#!': start
= 1
593 while start
< len(lines
) and string
.strip(lines
[start
]) in ('', '#'):
595 if start
< len(lines
) and lines
[start
][:1] == '#':
598 while end
< len(lines
) and lines
[end
][:1] == '#':
599 comments
.append(string
.expandtabs(lines
[end
]))
601 return string
.join(comments
, '')
603 # Look for a preceding block of comments at the same indentation.
605 indent
= indentsize(lines
[lnum
])
607 if end
>= 0 and string
.lstrip(lines
[end
])[:1] == '#' and \
608 indentsize(lines
[end
]) == indent
:
609 comments
= [string
.lstrip(string
.expandtabs(lines
[end
]))]
612 comment
= string
.lstrip(string
.expandtabs(lines
[end
]))
613 while comment
[:1] == '#' and indentsize(lines
[end
]) == indent
:
614 comments
[:0] = [comment
]
617 comment
= string
.lstrip(string
.expandtabs(lines
[end
]))
618 while comments
and string
.strip(comments
[0]) == '#':
620 while comments
and string
.strip(comments
[-1]) == '#':
622 return string
.join(comments
, '')
624 class EndOfBlock(Exception): pass
627 """Provide a tokeneater() method to detect the end of a code block."""
630 self
.islambda
= False
632 self
.passline
= False
635 def tokeneater(self
, type, token
, srow_scol
, erow_ecol
, line
):
636 srow
, scol
= srow_scol
637 erow
, ecol
= erow_ecol
639 # look for the first "def", "class" or "lambda"
640 if token
in ("def", "class", "lambda"):
641 if token
== "lambda":
644 self
.passline
= True # skip to the end of the line
645 elif type == tokenize
.NEWLINE
:
646 self
.passline
= False # stop skipping when a NEWLINE is seen
648 if self
.islambda
: # lambdas always end at the first NEWLINE
652 elif type == tokenize
.INDENT
:
653 self
.indent
= self
.indent
+ 1
655 elif type == tokenize
.DEDENT
:
656 self
.indent
= self
.indent
- 1
657 # the end of matching indent/dedent pairs end a block
658 # (note that this only works for "def"/"class" blocks,
659 # not e.g. for "if: else:" or "try: finally:" blocks)
662 elif self
.indent
== 0 and type not in (tokenize
.COMMENT
, tokenize
.NL
):
663 # any other token on the same indentation level end the previous
664 # block as well, except the pseudo-tokens COMMENT and NL.
668 """Extract the block of code at the top of the given list of lines."""
669 blockfinder
= BlockFinder()
671 tokenize
.tokenize(iter(lines
).next
, blockfinder
.tokeneater
)
672 except (EndOfBlock
, IndentationError):
674 return lines
[:blockfinder
.last
]
676 def getsourcelines(object):
677 """Return a list of source lines and starting line number for an object.
679 The argument may be a module, class, method, function, traceback, frame,
680 or code object. The source code is returned as a list of the lines
681 corresponding to the object and the line number indicates where in the
682 original source file the first line of code was found. An IOError is
683 raised if the source code cannot be retrieved."""
684 lines
, lnum
= findsource(object)
686 if ismodule(object): return lines
, 0
687 else: return getblock(lines
[lnum
:]), lnum
+ 1
689 def getsource(object):
690 """Return the text of the source code for an object.
692 The argument may be a module, class, method, function, traceback, frame,
693 or code object. The source code is returned as a single string. An
694 IOError is raised if the source code cannot be retrieved."""
695 lines
, lnum
= getsourcelines(object)
696 return string
.join(lines
, '')
698 # --------------------------------------------------- class tree extraction
699 def walktree(classes
, children
, parent
):
700 """Recursive helper function for getclasstree()."""
702 classes
.sort(key
=attrgetter('__module__', '__name__'))
704 results
.append((c
, c
.__bases
__))
706 results
.append(walktree(children
[c
], children
, c
))
709 def getclasstree(classes
, unique
=0):
710 """Arrange the given list of classes into a hierarchy of nested lists.
712 Where a nested list appears, it contains classes derived from the class
713 whose entry immediately precedes the list. Each entry is a 2-tuple
714 containing a class and a tuple of its base classes. If the 'unique'
715 argument is true, exactly one entry appears in the returned structure
716 for each class in the given list. Otherwise, classes using multiple
717 inheritance and their descendants will appear multiple times."""
722 for parent
in c
.__bases
__:
723 if not parent
in children
:
724 children
[parent
] = []
725 children
[parent
].append(c
)
726 if unique
and parent
in classes
: break
729 for parent
in children
:
730 if parent
not in classes
:
732 return walktree(roots
, children
, None)
734 # ------------------------------------------------ argument list extraction
735 Arguments
= namedtuple('Arguments', 'args varargs keywords')
738 """Get information about the arguments accepted by a code object.
740 Three things are returned: (args, varargs, varkw), where 'args' is
741 a list of argument names (possibly containing nested lists), and
742 'varargs' and 'varkw' are the names of the * and ** arguments or None."""
745 raise TypeError('arg is not a code object')
747 nargs
= co
.co_argcount
748 names
= co
.co_varnames
749 args
= list(names
[:nargs
])
752 # The following acrobatics are for anonymous (tuple) arguments.
753 for i
in range(nargs
):
754 if args
[i
][:1] in ('', '.'):
755 stack
, remain
, count
= [], [], []
756 while step
< len(co
.co_code
):
757 op
= ord(co
.co_code
[step
])
759 if op
>= dis
.HAVE_ARGUMENT
:
760 opname
= dis
.opname
[op
]
761 value
= ord(co
.co_code
[step
]) + ord(co
.co_code
[step
+1])*256
763 if opname
in ('UNPACK_TUPLE', 'UNPACK_SEQUENCE'):
766 elif opname
== 'STORE_FAST':
767 stack
.append(names
[value
])
769 # Special case for sublists of length 1: def foo((bar))
770 # doesn't generate the UNPACK_TUPLE bytecode, so if
771 # `remain` is empty here, we have such a sublist.
773 stack
[0] = [stack
[0]]
776 remain
[-1] = remain
[-1] - 1
777 while remain
[-1] == 0:
780 stack
[-size
:] = [stack
[-size
:]]
782 remain
[-1] = remain
[-1] - 1
787 if co
.co_flags
& CO_VARARGS
:
788 varargs
= co
.co_varnames
[nargs
]
791 if co
.co_flags
& CO_VARKEYWORDS
:
792 varkw
= co
.co_varnames
[nargs
]
793 return Arguments(args
, varargs
, varkw
)
795 ArgSpec
= namedtuple('ArgSpec', 'args varargs keywords defaults')
797 def getargspec(func
):
798 """Get the names and default values of a function's arguments.
800 A tuple of four things is returned: (args, varargs, varkw, defaults).
801 'args' is a list of the argument names (it may contain nested lists).
802 'varargs' and 'varkw' are the names of the * and ** arguments or None.
803 'defaults' is an n-tuple of the default values of the last n arguments.
808 if not isfunction(func
):
809 raise TypeError('arg is not a Python function')
810 args
, varargs
, varkw
= getargs(func
.func_code
)
811 return ArgSpec(args
, varargs
, varkw
, func
.func_defaults
)
813 ArgInfo
= namedtuple('ArgInfo', 'args varargs keywords locals')
815 def getargvalues(frame
):
816 """Get information about arguments passed into a particular frame.
818 A tuple of four things is returned: (args, varargs, varkw, locals).
819 'args' is a list of the argument names (it may contain nested lists).
820 'varargs' and 'varkw' are the names of the * and ** arguments or None.
821 'locals' is the locals dictionary of the given frame."""
822 args
, varargs
, varkw
= getargs(frame
.f_code
)
823 return args
, varargs
, varkw
, frame
.f_locals
827 return '(' + seq
[0] + ',)'
829 return '(' + string
.join(seq
, ', ') + ')'
831 def strseq(object, convert
, join
=joinseq
):
832 """Recursively walk a sequence, stringifying each element."""
833 if type(object) in (list, tuple):
834 return join(map(lambda o
, c
=convert
, j
=join
: strseq(o
, c
, j
), object))
836 return convert(object)
838 def formatargspec(args
, varargs
=None, varkw
=None, defaults
=None,
840 formatvarargs
=lambda name
: '*' + name
,
841 formatvarkw
=lambda name
: '**' + name
,
842 formatvalue
=lambda value
: '=' + repr(value
),
844 """Format an argument spec from the 4 values returned by getargspec.
846 The first four arguments are (args, varargs, varkw, defaults). The
847 other four arguments are the corresponding optional formatting functions
848 that are called to turn names and values into strings. The ninth
849 argument is an optional function to format the sequence of arguments."""
852 firstdefault
= len(args
) - len(defaults
)
853 for i
in range(len(args
)):
854 spec
= strseq(args
[i
], formatarg
, join
)
855 if defaults
and i
>= firstdefault
:
856 spec
= spec
+ formatvalue(defaults
[i
- firstdefault
])
858 if varargs
is not None:
859 specs
.append(formatvarargs(varargs
))
860 if varkw
is not None:
861 specs
.append(formatvarkw(varkw
))
862 return '(' + string
.join(specs
, ', ') + ')'
864 def formatargvalues(args
, varargs
, varkw
, locals,
866 formatvarargs
=lambda name
: '*' + name
,
867 formatvarkw
=lambda name
: '**' + name
,
868 formatvalue
=lambda value
: '=' + repr(value
),
870 """Format an argument spec from the 4 values returned by getargvalues.
872 The first four arguments are (args, varargs, varkw, locals). The
873 next four arguments are the corresponding optional formatting functions
874 that are called to turn names and values into strings. The ninth
875 argument is an optional function to format the sequence of arguments."""
876 def convert(name
, locals=locals,
877 formatarg
=formatarg
, formatvalue
=formatvalue
):
878 return formatarg(name
) + formatvalue(locals[name
])
880 for i
in range(len(args
)):
881 specs
.append(strseq(args
[i
], convert
, join
))
883 specs
.append(formatvarargs(varargs
) + formatvalue(locals[varargs
]))
885 specs
.append(formatvarkw(varkw
) + formatvalue(locals[varkw
]))
886 return '(' + string
.join(specs
, ', ') + ')'
888 # -------------------------------------------------- stack frame extraction
890 Traceback
= namedtuple('Traceback', 'filename lineno function code_context index')
892 def getframeinfo(frame
, context
=1):
893 """Get information about a frame or traceback object.
895 A tuple of five things is returned: the filename, the line number of
896 the current line, the function name, a list of lines of context from
897 the source code, and the index of the current line within that list.
898 The optional second argument specifies the number of lines of context
899 to return, which are centered around the current line."""
900 if istraceback(frame
):
901 lineno
= frame
.tb_lineno
902 frame
= frame
.tb_frame
904 lineno
= frame
.f_lineno
905 if not isframe(frame
):
906 raise TypeError('arg is not a frame or traceback object')
908 filename
= getsourcefile(frame
) or getfile(frame
)
910 start
= lineno
- 1 - context
//2
912 lines
, lnum
= findsource(frame
)
916 start
= max(start
, 1)
917 start
= max(0, min(start
, len(lines
) - context
))
918 lines
= lines
[start
:start
+context
]
919 index
= lineno
- 1 - start
923 return Traceback(filename
, lineno
, frame
.f_code
.co_name
, lines
, index
)
925 def getlineno(frame
):
926 """Get the line number from a frame object, allowing for optimization."""
927 # FrameType.f_lineno is now a descriptor that grovels co_lnotab
928 return frame
.f_lineno
930 def getouterframes(frame
, context
=1):
931 """Get a list of records for a frame and all higher (calling) frames.
933 Each record contains a frame object, filename, line number, function
934 name, a list of lines of context, and index within the context."""
937 framelist
.append((frame
,) + getframeinfo(frame
, context
))
941 def getinnerframes(tb
, context
=1):
942 """Get a list of records for a traceback's frame and all lower frames.
944 Each record contains a frame object, filename, line number, function
945 name, a list of lines of context, and index within the context."""
948 framelist
.append((tb
.tb_frame
,) + getframeinfo(tb
, context
))
952 currentframe
= sys
._getframe
954 def stack(context
=1):
955 """Return a list of records for the stack above the caller's frame."""
956 return getouterframes(sys
._getframe
(1), context
)
958 def trace(context
=1):
959 """Return a list of records for the stack below the current exception."""
960 return getinnerframes(sys
.exc_info()[2], context
)