# -*- coding: iso-8859-1 -*-
"""Get useful information from live Python objects.
This module encapsulates the interface provided by the internal special
attributes (func_*, co_*, im_*, tb_*, etc.) in a friendlier fashion.
It also provides some help for examining source code and class layout.
Here are some of the useful functions provided by this module:
ismodule(), isclass(), ismethod(), isfunction(), isgeneratorfunction(),
isgenerator(), istraceback(), isframe(), iscode(), isbuiltin(),
isroutine() - check object types
getmembers() - get members of an object that satisfy a given condition
getfile(), getsourcefile(), getsource() - find an object's source code
getdoc(), getcomments() - get documentation on an object
getmodule() - determine the module that an object came from
getclasstree() - arrange classes so as to represent their hierarchy
getargspec(), getargvalues(), getcallargs() - get info about function arguments
formatargspec(), formatargvalues() - format an argument spec
getouterframes(), getinnerframes() - get info about frames
currentframe() - get the current stack frame
stack(), trace() - get info about frames on the stack or in a traceback
"""
# This module is in the public domain. No warranties.
__author__ = 'Ka-Ping Yee <ping@lfw.org>'
__date__ = '1 Jan 2001'
import sys
import os
import types
import string
import re
import dis
import imp
import tokenize
import linecache
from operator import attrgetter
from collections import namedtuple
# These constants are from Include/code.h.
CO_OPTIMIZED, CO_NEWLOCALS, CO_VARARGS, CO_VARKEYWORDS = 0x1, 0x2, 0x4, 0x8
CO_NESTED, CO_GENERATOR, CO_NOFREE = 0x10, 0x20, 0x40
# See Include/object.h
TPFLAGS_IS_ABSTRACT = 1 << 20
# ----------------------------------------------------------- type-checking
def ismodule(object):
"""Return true if the object is a module.
Module objects provide these attributes:
__doc__ documentation string
__file__ filename (missing for built-in modules)"""
return isinstance(object, types.ModuleType)
def isclass(object):
"""Return true if the object is a class.
Class objects provide these attributes:
__doc__ documentation string
__module__ name of module in which this class was defined"""
return isinstance(object, (type, types.ClassType))
def ismethod(object):
"""Return true if the object is an instance method.
Instance method objects provide these attributes:
__doc__ documentation string
__name__ name with which this method was defined
im_class class object in which this method belongs
im_func function object containing implementation of method
im_self instance to which this method is bound, or None"""
return isinstance(object, types.MethodType)
def ismethoddescriptor(object):
"""Return true if the object is a method descriptor.
But not if ismethod() or isclass() or isfunction() are true.
This is new in Python 2.2, and, for example, is true of int.__add__.
An object passing this test has a __get__ attribute but not a __set__
attribute, but beyond that the set of attributes varies. __name__ is
usually sensible, and __doc__ often is.
Methods implemented via descriptors that also pass one of the other
tests return false from the ismethoddescriptor() test, simply because
the other tests promise more -- you can, e.g., count on having the
im_func attribute (etc) when an object passes ismethod()."""
return (hasattr(object, "__get__")
and not hasattr(object, "__set__") # else it's a data descriptor
and not ismethod(object) # mutual exclusion
and not isfunction(object)
and not isclass(object))
def isdatadescriptor(object):
"""Return true if the object is a data descriptor.
Data descriptors have both a __get__ and a __set__ attribute. Examples are
properties (defined in Python) and getsets and members (defined in C).
Typically, data descriptors will also have __name__ and __doc__ attributes
(properties, getsets, and members have both of these attributes), but this
is not guaranteed."""
return (hasattr(object, "__set__") and hasattr(object, "__get__"))
if hasattr(types, 'MemberDescriptorType'):
# CPython and equivalent
def ismemberdescriptor(object):
"""Return true if the object is a member descriptor.
Member descriptors are specialized descriptors defined in extension
modules."""
return isinstance(object, types.MemberDescriptorType)
else:
# Other implementations
def ismemberdescriptor(object):
"""Return true if the object is a member descriptor.
Member descriptors are specialized descriptors defined in extension
modules."""
return False
if hasattr(types, 'GetSetDescriptorType'):
# CPython and equivalent
def isgetsetdescriptor(object):
"""Return true if the object is a getset descriptor.
getset descriptors are specialized descriptors defined in extension
modules."""
return isinstance(object, types.GetSetDescriptorType)
else:
# Other implementations
def isgetsetdescriptor(object):
"""Return true if the object is a getset descriptor.
getset descriptors are specialized descriptors defined in extension
modules."""
return False
def isfunction(object):
"""Return true if the object is a user-defined function.
Function objects provide these attributes:
__doc__ documentation string
__name__ name with which this function was defined
func_code code object containing compiled function bytecode
func_defaults tuple of any default values for arguments
func_doc (same as __doc__)
func_globals global namespace in which this function was defined
func_name (same as __name__)"""
return isinstance(object, types.FunctionType)
def isgeneratorfunction(object):
"""Return true if the object is a user-defined generator function.
Generator function objects provides same attributes as functions.
See help(isfunction) for attributes listing."""
return bool((isfunction(object) or ismethod(object)) and
object.func_code.co_flags & CO_GENERATOR)
def isgenerator(object):
"""Return true if the object is a generator.
Generator objects provide these attributes:
__iter__ defined to support iteration over container
close raises a new GeneratorExit exception inside the
generator to terminate the iteration
gi_code code object
gi_frame frame object or possibly None once the generator has
been exhausted
gi_running set to 1 when generator is executing, 0 otherwise
next return the next item from the container
send resumes the generator and "sends" a value that becomes
the result of the current yield-expression
throw used to raise an exception inside the generator"""
return isinstance(object, types.GeneratorType)
def istraceback(object):
"""Return true if the object is a traceback.
Traceback objects provide these attributes:
tb_frame frame object at this level
tb_lasti index of last attempted instruction in bytecode
tb_lineno current line number in Python source code
tb_next next inner traceback object (called by this level)"""
return isinstance(object, types.TracebackType)
def isframe(object):
"""Return true if the object is a frame object.
Frame objects provide these attributes:
f_back next outer frame object (this frame's caller)
f_builtins built-in namespace seen by this frame
f_code code object being executed in this frame
f_exc_traceback traceback if raised in this frame, or None
f_exc_type exception type if raised in this frame, or None
f_exc_value exception value if raised in this frame, or None
f_globals global namespace seen by this frame
f_lasti index of last attempted instruction in bytecode
f_lineno current line number in Python source code
f_locals local namespace seen by this frame
f_restricted 0 or 1 if frame is in restricted execution mode
f_trace tracing function for this frame, or None"""
return isinstance(object, types.FrameType)
def iscode(object):
"""Return true if the object is a code object.
Code objects provide these attributes:
co_argcount number of arguments (not including * or ** args)
co_code string of raw compiled bytecode
co_consts tuple of constants used in the bytecode
co_filename name of file in which this code object was created
co_firstlineno number of first line in Python source code
co_flags bitmap: 1=optimized | 2=newlocals | 4=*arg | 8=**arg
co_lnotab encoded mapping of line numbers to bytecode indices
co_name name with which this code object was defined
co_names tuple of names of local variables
co_nlocals number of local variables
co_stacksize virtual machine stack space required
co_varnames tuple of names of arguments and local variables"""
return isinstance(object, types.CodeType)
def isbuiltin(object):
"""Return true if the object is a built-in function or method.
Built-in functions and methods provide these attributes:
__doc__ documentation string
__name__ original name of this function or method
__self__ instance to which a method is bound, or None"""
return isinstance(object, types.BuiltinFunctionType)
def isroutine(object):
"""Return true if the object is any kind of function or method."""
return (isbuiltin(object)
or isfunction(object)
or ismethod(object)
or ismethoddescriptor(object))
def isabstract(object):
"""Return true if the object is an abstract base class (ABC)."""
return bool(isinstance(object, type) and object.__flags__ & TPFLAGS_IS_ABSTRACT)
def getmembers(object, predicate=None):
"""Return all members of an object as (name, value) pairs sorted by name.
Optionally, only return members that satisfy a given predicate."""
results = []
for key in dir(object):
try:
value = getattr(object, key)
except AttributeError:
continue
if not predicate or predicate(value):
results.append((key, value))
results.sort()
return results
Attribute = namedtuple('Attribute', 'name kind defining_class object')
def classify_class_attrs(cls):
"""Return list of attribute-descriptor tuples.
For each name in dir(cls), the return list contains a 4-tuple
with these elements:
0. The name (a string).
1. The kind of attribute this is, one of these strings:
'class method' created via classmethod()
'static method' created via staticmethod()
'property' created via property()
'method' any other flavor of method
'data' not a method
2. The class which defined this attribute (a class).
3. The object as obtained directly from the defining class's
__dict__, not via getattr. This is especially important for
data attributes: C.data is just a data object, but
C.__dict__['data'] may be a data descriptor with additional
info, like a __doc__ string.
"""
mro = getmro(cls)
names = dir(cls)
result = []
for name in names:
# Get the object associated with the name, and where it was defined.
# Getting an obj from the __dict__ sometimes reveals more than
# using getattr. Static and class methods are dramatic examples.
# Furthermore, some objects may raise an Exception when fetched with
# getattr(). This is the case with some descriptors (bug #1785).
# Thus, we only use getattr() as a last resort.
homecls = None
for base in (cls,) + mro:
if name in base.__dict__:
obj = base.__dict__[name]
homecls = base
break
else:
obj = getattr(cls, name)
homecls = getattr(obj, "__objclass__", homecls)
# Classify the object.
if isinstance(obj, staticmethod):
kind = "static method"
elif isinstance(obj, classmethod):
kind = "class method"
elif isinstance(obj, property):
kind = "property"
elif ismethoddescriptor(obj):
kind = "method"
elif isdatadescriptor(obj):
kind = "data"
else:
obj_via_getattr = getattr(cls, name)
if (ismethod(obj_via_getattr) or
ismethoddescriptor(obj_via_getattr)):
kind = "method"
else:
kind = "data"
obj = obj_via_getattr
result.append(Attribute(name, kind, homecls, obj))
return result
# ----------------------------------------------------------- class helpers
def _searchbases(cls, accum):
# Simulate the "classic class" search order.
if cls in accum:
return
accum.append(cls)
for base in cls.__bases__:
_searchbases(base, accum)
def getmro(cls):
"Return tuple of base classes (including cls) in method resolution order."
if hasattr(cls, "__mro__"):
return cls.__mro__
else:
result = []
_searchbases(cls, result)
return tuple(result)
# -------------------------------------------------- source code extraction
def indentsize(line):
"""Return the indent size, in spaces, at the start of a line of text."""
expline = string.expandtabs(line)
return len(expline) - len(string.lstrip(expline))
def getdoc(object):
"""Get the documentation string for an object.
All tabs are expanded to spaces. To clean up docstrings that are
indented to line up with blocks of code, any whitespace than can be
uniformly removed from the second line onwards is removed."""
try:
doc = object.__doc__
except AttributeError:
return None
if not isinstance(doc, types.StringTypes):
return None
return cleandoc(doc)
def cleandoc(doc):
"""Clean up indentation from docstrings.
Any whitespace that can be uniformly removed from the second line
onwards is removed."""
try:
lines = string.split(string.expandtabs(doc), '\n')
except UnicodeError:
return None
else:
# Find minimum indentation of any non-blank lines after first line.
margin = sys.maxint
for line in lines[1:]:
content = len(string.lstrip(line))
if content:
indent = len(line) - content
margin = min(margin, indent)
# Remove indentation.
if lines:
lines[0] = lines[0].lstrip()
if margin < sys.maxint:
for i in range(1, len(lines)): lines[i] = lines[i][margin:]
# Remove any trailing or leading blank lines.
while lines and not lines[-1]:
lines.pop()
while lines and not lines[0]:
lines.pop(0)
return string.join(lines, '\n')
def getfile(object):
"""Work out which source or compiled file an object was defined in."""
if ismodule(object):
if hasattr(object, '__file__'):
return object.__file__
raise TypeError('{!r} is a built-in module'.format(object))
if isclass(object):
object = sys.modules.get(object.__module__)
if hasattr(object, '__file__'):
return object.__file__
raise TypeError('{!r} is a built-in class'.format(object))
if ismethod(object):
object = object.im_func
if isfunction(object):
object = object.func_code
if istraceback(object):
object = object.tb_frame
if isframe(object):
object = object.f_code
if iscode(object):
return object.co_filename
raise TypeError('{!r} is not a module, class, method, '
'function, traceback, frame, or code object'.format(object))
ModuleInfo = namedtuple('ModuleInfo', 'name suffix mode module_type')
def getmoduleinfo(path):
"""Get the module name, suffix, mode, and module type for a given file."""
filename = os.path.basename(path)
suffixes = map(lambda info:
(-len(info[0]), info[0], info[1], info[2]),
imp.get_suffixes())
suffixes.sort() # try longest suffixes first, in case they overlap
for neglen, suffix, mode, mtype in suffixes:
if filename[neglen:] == suffix:
return ModuleInfo(filename[:neglen], suffix, mode, mtype)
def getmodulename(path):
"""Return the module name for a given file, or None."""
info = getmoduleinfo(path)
if info: return info[0]
def getsourcefile(object):
"""Return the filename that can be used to locate an object's source.
Return None if no way can be identified to get the source.
"""
filename = getfile(object)
if string.lower(filename[-4:]) in ('.pyc', '.pyo'):
filename = filename[:-4] + '.py'
for suffix, mode, kind in imp.get_suffixes():
if 'b' in mode and string.lower(filename[-len(suffix):]) == suffix:
# Looks like a binary file. We want to only return a text file.
return None
if os.path.exists(filename):
return filename
# only return a non-existent filename if the module has a PEP 302 loader
if hasattr(getmodule(object, filename), '__loader__'):
return filename
# or it is in the linecache
if filename in linecache.cache:
return filename
def getabsfile(object, _filename=None):
"""Return an absolute path to the source or compiled file for an object.
The idea is for each object to have a unique origin, so this routine
normalizes the result as much as possible."""
if _filename is None:
_filename = getsourcefile(object) or getfile(object)
return os.path.normcase(os.path.abspath(_filename))
modulesbyfile = {}
_filesbymodname = {}
def getmodule(object, _filename=None):
"""Return the module an object was defined in, or None if not found."""
if ismodule(object):
return object
if hasattr(object, '__module__'):
return sys.modules.get(object.__module__)
# Try the filename to modulename cache
if _filename is not None and _filename in modulesbyfile:
return sys.modules.get(modulesbyfile[_filename])
# Try the cache again with the absolute file name
try:
file = getabsfile(object, _filename)
except TypeError:
return None
if file in modulesbyfile:
return sys.modules.get(modulesbyfile[file])
# Update the filename to module name cache and check yet again
# Copy sys.modules in order to cope with changes while iterating
for modname, module in sys.modules.items():
if ismodule(module) and hasattr(module, '__file__'):
f = module.__file__
if f == _filesbymodname.get(modname, None):
# Have already mapped this module, so skip it
continue
_filesbymodname[modname] = f
f = getabsfile(module)
# Always map to the name the module knows itself by
modulesbyfile[f] = modulesbyfile[
os.path.realpath(f)] = module.__name__
if file in modulesbyfile:
return sys.modules.get(modulesbyfile[file])
# Check the main module
main = sys.modules['__main__']
if not hasattr(object, '__name__'):
return None
if hasattr(main, object.__name__):
mainobject = getattr(main, object.__name__)
if mainobject is object:
return main
# Check builtins
builtin = sys.modules['__builtin__']
if hasattr(builtin, object.__name__):
builtinobject = getattr(builtin, object.__name__)
if builtinobject is object:
return builtin
def findsource(object):
"""Return the entire source file and starting line number for an object.
The argument may be a module, class, method, function, traceback, frame,
or code object. The source code is returned as a list of all the lines
in the file and the line number indexes a line in that list. An IOError
is raised if the source code cannot be retrieved."""
file = getfile(object)
sourcefile = getsourcefile(object)
if not sourcefile and file[:1] + file[-1:] != '<>':
raise IOError('source code not available')
file = sourcefile if sourcefile else file
module = getmodule(object, file)
if module:
lines = linecache.getlines(file, module.__dict__)
else:
lines = linecache.getlines(file)
if not lines:
raise IOError('could not get source code')
if ismodule(object):
return lines, 0
if isclass(object):
name = object.__name__
pat = re.compile(r'^(\s*)class\s*' + name + r'\b')
# make some effort to find the best matching class definition:
# use the one with the least indentation, which is the one
# that's most probably not inside a function definition.
candidates = []
for i in range(len(lines)):
match = pat.match(lines[i])
if match:
# if it's at toplevel, it's already the best one
if lines[i][0] == 'c':
return lines, i
# else add whitespace to candidate list
candidates.append((match.group(1), i))
if candidates:
# this will sort by whitespace, and by line number,
# less whitespace first
candidates.sort()
return lines, candidates[0][1]
else:
raise IOError('could not find class definition')
if ismethod(object):
object = object.im_func
if isfunction(object):
object = object.func_code
if istraceback(object):
object = object.tb_frame
if isframe(object):
object = object.f_code
if iscode(object):
if not hasattr(object, 'co_firstlineno'):
raise IOError('could not find function definition')
lnum = object.co_firstlineno - 1
pat = re.compile(r'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)')
while lnum > 0:
if pat.match(lines[lnum]): break
lnum = lnum - 1
return lines, lnum
raise IOError('could not find code object')
def getcomments(object):
"""Get lines of comments immediately preceding an object's source code.
Returns None when source can't be found.
"""
try:
lines, lnum = findsource(object)
except (IOError, TypeError):
return None
if ismodule(object):
# Look for a comment block at the top of the file.
start = 0
if lines and lines[0][:2] == '#!': start = 1
while start < len(lines) and string.strip(lines[start]) in ('', '#'):
start = start + 1
if start < len(lines) and lines[start][:1] == '#':
comments = []
end = start
while end < len(lines) and lines[end][:1] == '#':
comments.append(string.expandtabs(lines[end]))
end = end + 1
return string.join(comments, '')
# Look for a preceding block of comments at the same indentation.
elif lnum > 0:
indent = indentsize(lines[lnum])
end = lnum - 1
if end >= 0 and string.lstrip(lines[end])[:1] == '#' and \
indentsize(lines[end]) == indent:
comments = [string.lstrip(string.expandtabs(lines[end]))]
if end > 0:
end = end - 1
comment = string.lstrip(string.expandtabs(lines[end]))
while comment[:1] == '#' and indentsize(lines[end]) == indent:
comments[:0] = [comment]
end = end - 1
if end < 0: break
comment = string.lstrip(string.expandtabs(lines[end]))
while comments and string.strip(comments[0]) == '#':
comments[:1] = []
while comments and string.strip(comments[-1]) == '#':
comments[-1:] = []
return string.join(comments, '')
class EndOfBlock(Exception): pass
class BlockFinder:
"""Provide a tokeneater() method to detect the end of a code block."""
def __init__(self):
self.indent = 0
self.islambda = False
self.started = False
self.passline = False
self.last = 1
def tokeneater(self, type, token, srow_scol, erow_ecol, line):
srow, scol = srow_scol
erow, ecol = erow_ecol
if not self.started:
# look for the first "def", "class" or "lambda"
if token in ("def", "class", "lambda"):
if token == "lambda":
self.islambda = True
self.started = True
self.passline = True # skip to the end of the line
elif type == tokenize.NEWLINE:
self.passline = False # stop skipping when a NEWLINE is seen
self.last = srow
if self.islambda: # lambdas always end at the first NEWLINE
raise EndOfBlock
elif self.passline:
pass
elif type == tokenize.INDENT:
self.indent = self.indent + 1
self.passline = True
elif type == tokenize.DEDENT:
self.indent = self.indent - 1
# the end of matching indent/dedent pairs end a block
# (note that this only works for "def"/"class" blocks,
# not e.g. for "if: else:" or "try: finally:" blocks)
if self.indent <= 0:
raise EndOfBlock
elif self.indent == 0 and type not in (tokenize.COMMENT, tokenize.NL):
# any other token on the same indentation level end the previous
# block as well, except the pseudo-tokens COMMENT and NL.
raise EndOfBlock
def getblock(lines):
"""Extract the block of code at the top of the given list of lines."""
blockfinder = BlockFinder()
try:
tokenize.tokenize(iter(lines).next, blockfinder.tokeneater)
except (EndOfBlock, IndentationError):
pass
return lines[:blockfinder.last]
def getsourcelines(object):
"""Return a list of source lines and starting line number for an object.
The argument may be a module, class, method, function, traceback, frame,
or code object. The source code is returned as a list of the lines
corresponding to the object and the line number indicates where in the
original source file the first line of code was found. An IOError is
raised if the source code cannot be retrieved."""
lines, lnum = findsource(object)
if ismodule(object): return lines, 0
else: return getblock(lines[lnum:]), lnum + 1
def getsource(object):
"""Return the text of the source code for an object.
The argument may be a module, class, method, function, traceback, frame,
or code object. The source code is returned as a single string. An
IOError is raised if the source code cannot be retrieved."""
lines, lnum = getsourcelines(object)
return string.join(lines, '')
# --------------------------------------------------- class tree extraction
def walktree(classes, children, parent):
"""Recursive helper function for getclasstree()."""
results = []
classes.sort(key=attrgetter('__module__', '__name__'))
for c in classes:
results.append((c, c.__bases__))
if c in children:
results.append(walktree(children[c], children, c))
return results
def getclasstree(classes, unique=0):
"""Arrange the given list of classes into a hierarchy of nested lists.
Where a nested list appears, it contains classes derived from the class
whose entry immediately precedes the list. Each entry is a 2-tuple
containing a class and a tuple of its base classes. If the 'unique'
argument is true, exactly one entry appears in the returned structure
for each class in the given list. Otherwise, classes using multiple
inheritance and their descendants will appear multiple times."""
children = {}
roots = []
for c in classes:
if c.__bases__:
for parent in c.__bases__:
if not parent in children:
children[parent] = []
if c not in children[parent]:
children[parent].append(c)
if unique and parent in classes: break
elif c not in roots:
roots.append(c)
for parent in children:
if parent not in classes:
roots.append(parent)
return walktree(roots, children, None)
# ------------------------------------------------ argument list extraction
Arguments = namedtuple('Arguments', 'args varargs keywords')
def getargs(co):
"""Get information about the arguments accepted by a code object.
Three things are returned: (args, varargs, varkw), where 'args' is
a list of argument names (possibly containing nested lists), and
'varargs' and 'varkw' are the names of the * and ** arguments or None."""
if not iscode(co):
raise TypeError('{!r} is not a code object'.format(co))
nargs = co.co_argcount
names = co.co_varnames
args = list(names[:nargs])
step = 0
# The following acrobatics are for anonymous (tuple) arguments.
for i in range(nargs):
if args[i][:1] in ('', '.'):
stack, remain, count = [], [], []
while step < len(co.co_code):
op = ord(co.co_code[step])
step = step + 1
if op >= dis.HAVE_ARGUMENT:
opname = dis.opname[op]
value = ord(co.co_code[step]) + ord(co.co_code[step+1])*256
step = step + 2
if opname in ('UNPACK_TUPLE', 'UNPACK_SEQUENCE'):
remain.append(value)
count.append(value)
elif opname == 'STORE_FAST':
stack.append(names[value])
# Special case for sublists of length 1: def foo((bar))
# doesn't generate the UNPACK_TUPLE bytecode, so if
# `remain` is empty here, we have such a sublist.
if not remain:
stack[0] = [stack[0]]
break
else:
remain[-1] = remain[-1] - 1
while remain[-1] == 0:
remain.pop()
size = count.pop()
stack[-size:] = [stack[-size:]]
if not remain: break
remain[-1] = remain[-1] - 1
if not remain: break
args[i] = stack[0]
varargs = None
if co.co_flags & CO_VARARGS:
varargs = co.co_varnames[nargs]
nargs = nargs + 1
varkw = None
if co.co_flags & CO_VARKEYWORDS:
varkw = co.co_varnames[nargs]
return Arguments(args, varargs, varkw)
ArgSpec = namedtuple('ArgSpec', 'args varargs keywords defaults')
def getargspec(func):
"""Get the names and default values of a function's arguments.
A tuple of four things is returned: (args, varargs, varkw, defaults).
'args' is a list of the argument names (it may contain nested lists).
'varargs' and 'varkw' are the names of the * and ** arguments or None.
'defaults' is an n-tuple of the default values of the last n arguments.
"""
if ismethod(func):
func = func.im_func
if not isfunction(func):
raise TypeError('{!r} is not a Python function'.format(func))
args, varargs, varkw = getargs(func.func_code)
return ArgSpec(args, varargs, varkw, func.func_defaults)
ArgInfo = namedtuple('ArgInfo', 'args varargs keywords locals')
def getargvalues(frame):
"""Get information about arguments passed into a particular frame.
A tuple of four things is returned: (args, varargs, varkw, locals).
'args' is a list of the argument names (it may contain nested lists).
'varargs' and 'varkw' are the names of the * and ** arguments or None.
'locals' is the locals dictionary of the given frame."""
args, varargs, varkw = getargs(frame.f_code)
return ArgInfo(args, varargs, varkw, frame.f_locals)
def joinseq(seq):
if len(seq) == 1:
return '(' + seq[0] + ',)'
else:
return '(' + string.join(seq, ', ') + ')'
def strseq(object, convert, join=joinseq):
"""Recursively walk a sequence, stringifying each element."""
if type(object) in (list, tuple):
return join(map(lambda o, c=convert, j=join: strseq(o, c, j), object))
else:
return convert(object)
def formatargspec(args, varargs=None, varkw=None, defaults=None,
formatarg=str,
formatvarargs=lambda name: '*' + name,
formatvarkw=lambda name: '**' + name,
formatvalue=lambda value: '=' + repr(value),
join=joinseq):
"""Format an argument spec from the 4 values returned by getargspec.
The first four arguments are (args, varargs, varkw, defaults). The
other four arguments are the corresponding optional formatting functions
that are called to turn names and values into strings. The ninth
argument is an optional function to format the sequence of arguments."""
specs = []
if defaults:
firstdefault = len(args) - len(defaults)
for i, arg in enumerate(args):
spec = strseq(arg, formatarg, join)
if defaults and i >= firstdefault:
spec = spec + formatvalue(defaults[i - firstdefault])
specs.append(spec)
if varargs is not None:
specs.append(formatvarargs(varargs))
if varkw is not None:
specs.append(formatvarkw(varkw))
return '(' + string.join(specs, ', ') + ')'
def formatargvalues(args, varargs, varkw, locals,
formatarg=str,
formatvarargs=lambda name: '*' + name,
formatvarkw=lambda name: '**' + name,
formatvalue=lambda value: '=' + repr(value),
join=joinseq):
"""Format an argument spec from the 4 values returned by getargvalues.
The first four arguments are (args, varargs, varkw, locals). The
next four arguments are the corresponding optional formatting functions
that are called to turn names and values into strings. The ninth
argument is an optional function to format the sequence of arguments."""
def convert(name, locals=locals,
formatarg=formatarg, formatvalue=formatvalue):
return formatarg(name) + formatvalue(locals[name])
specs = []
for i in range(len(args)):
specs.append(strseq(args[i], convert, join))
if varargs:
specs.append(formatvarargs(varargs) + formatvalue(locals[varargs]))
if varkw:
specs.append(formatvarkw(varkw) + formatvalue(locals[varkw]))
return '(' + string.join(specs, ', ') + ')'
def getcallargs(func, *positional, **named):
"""Get the mapping of arguments to values.
A dict is returned, with keys the function argument names (including the
names of the * and ** arguments, if any), and values the respective bound
values from 'positional' and 'named'."""
args, varargs, varkw, defaults = getargspec(func)
f_name = func.__name__
arg2value = {}
# The following closures are basically because of tuple parameter unpacking.
assigned_tuple_params = []
def assign(arg, value):
if isinstance(arg, str):
arg2value[arg] = value
else:
assigned_tuple_params.append(arg)
value = iter(value)
for i, subarg in enumerate(arg):
try:
subvalue = next(value)
except StopIteration:
raise ValueError('need more than %d %s to unpack' %
(i, 'values' if i > 1 else 'value'))
assign(subarg,subvalue)
try:
next(value)
except StopIteration:
pass
else:
raise ValueError('too many values to unpack')
def is_assigned(arg):
if isinstance(arg,str):
return arg in arg2value
return arg in assigned_tuple_params
if ismethod(func) and func.im_self is not None:
# implicit 'self' (or 'cls' for classmethods) argument
positional = (func.im_self,) + positional
num_pos = len(positional)
num_total = num_pos + len(named)
num_args = len(args)
num_defaults = len(defaults) if defaults else 0
for arg, value in zip(args, positional):
assign(arg, value)
if varargs:
if num_pos > num_args:
assign(varargs, positional[-(num_pos-num_args):])
else:
assign(varargs, ())
elif 0 < num_args < num_pos:
raise TypeError('%s() takes %s %d %s (%d given)' % (
f_name, 'at most' if defaults else 'exactly', num_args,
'arguments' if num_args > 1 else 'argument', num_total))
elif num_args == 0 and num_total:
if varkw:
if num_pos:
# XXX: We should use num_pos, but Python also uses num_total:
raise TypeError('%s() takes exactly 0 arguments '
'(%d given)' % (f_name, num_total))
else:
raise TypeError('%s() takes no arguments (%d given)' %
(f_name, num_total))
for arg in args:
if isinstance(arg, str) and arg in named:
if is_assigned(arg):
raise TypeError("%s() got multiple values for keyword "
"argument '%s'" % (f_name, arg))
else:
assign(arg, named.pop(arg))
if defaults: # fill in any missing values with the defaults
for arg, value in zip(args[-num_defaults:], defaults):
if not is_assigned(arg):
assign(arg, value)
if varkw:
assign(varkw, named)
elif named:
unexpected = next(iter(named))
if isinstance(unexpected, unicode):
unexpected = unexpected.encode(sys.getdefaultencoding(), 'replace')
raise TypeError("%s() got an unexpected keyword argument '%s'" %
(f_name, unexpected))
unassigned = num_args - len([arg for arg in args if is_assigned(arg)])
if unassigned:
num_required = num_args - num_defaults
raise TypeError('%s() takes %s %d %s (%d given)' % (
f_name, 'at least' if defaults else 'exactly', num_required,
'arguments' if num_required > 1 else 'argument', num_total))
return arg2value
# -------------------------------------------------- stack frame extraction
Traceback = namedtuple('Traceback', 'filename lineno function code_context index')
def getframeinfo(frame, context=1):
"""Get information about a frame or traceback object.
A tuple of five things is returned: the filename, the line number of
the current line, the function name, a list of lines of context from
the source code, and the index of the current line within that list.
The optional second argument specifies the number of lines of context
to return, which are centered around the current line."""
if istraceback(frame):
lineno = frame.tb_lineno
frame = frame.tb_frame
else:
lineno = frame.f_lineno
if not isframe(frame):
raise TypeError('{!r} is not a frame or traceback object'.format(frame))
filename = getsourcefile(frame) or getfile(frame)
if context > 0:
start = lineno - 1 - context//2
try:
lines, lnum = findsource(frame)
except IOError:
lines = index = None
else:
start = max(start, 1)
start = max(0, min(start, len(lines) - context))
lines = lines[start:start+context]
index = lineno - 1 - start
else:
lines = index = None
return Traceback(filename, lineno, frame.f_code.co_name, lines, index)
def getlineno(frame):
"""Get the line number from a frame object, allowing for optimization."""
# FrameType.f_lineno is now a descriptor that grovels co_lnotab
return frame.f_lineno
def getouterframes(frame, context=1):
"""Get a list of records for a frame and all higher (calling) frames.
Each record contains a frame object, filename, line number, function
name, a list of lines of context, and index within the context."""
framelist = []
while frame:
framelist.append((frame,) + getframeinfo(frame, context))
frame = frame.f_back
return framelist
def getinnerframes(tb, context=1):
"""Get a list of records for a traceback's frame and all lower frames.
Each record contains a frame object, filename, line number, function
name, a list of lines of context, and index within the context."""
framelist = []
while tb:
framelist.append((tb.tb_frame,) + getframeinfo(tb, context))
tb = tb.tb_next
return framelist
if hasattr(sys, '_getframe'):
currentframe = sys._getframe
else:
currentframe = lambda _=None: None
def stack(context=1):
"""Return a list of records for the stack above the caller's frame."""
return getouterframes(sys._getframe(1), context)
def trace(context=1):
"""Return a list of records for the stack below the current exception."""
return getinnerframes(sys.exc_info()[2], context)
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