symbian-qemu-0.9.1-12/python-2.6.1/Lib/inspect.py
changeset 1 2fb8b9db1c86
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0:ffa851df0825 1:2fb8b9db1c86
       
     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() - 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@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, types.ClassType) or hasattr(object, '__bases__')
       
    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 provides same attributes as functions.
       
   159 
       
   160     See isfunction.__doc__ for attributes listing."""
       
   161     if (isfunction(object) or ismethod(object)) and \
       
   162         object.func_code.co_flags & CO_GENERATOR:
       
   163         return True
       
   164 
       
   165 def isgenerator(object):
       
   166     """Return true if the object is a generator.
       
   167 
       
   168     Generator objects provide these attributes:
       
   169         __iter__        defined to support interation over container
       
   170         close           raises a new GeneratorExit exception inside the
       
   171                         generator to terminate the iteration
       
   172         gi_code         code object
       
   173         gi_frame        frame object or possibly None once the generator has
       
   174                         been exhausted
       
   175         gi_running      set to 1 when generator is executing, 0 otherwise
       
   176         next            return the next item from the container
       
   177         send            resumes the generator and "sends" a value that becomes
       
   178                         the result of the current yield-expression
       
   179         throw           used to raise an exception inside the generator"""
       
   180     return isinstance(object, types.GeneratorType)
       
   181 
       
   182 def istraceback(object):
       
   183     """Return true if the object is a traceback.
       
   184 
       
   185     Traceback objects provide these attributes:
       
   186         tb_frame        frame object at this level
       
   187         tb_lasti        index of last attempted instruction in bytecode
       
   188         tb_lineno       current line number in Python source code
       
   189         tb_next         next inner traceback object (called by this level)"""
       
   190     return isinstance(object, types.TracebackType)
       
   191 
       
   192 def isframe(object):
       
   193     """Return true if the object is a frame object.
       
   194 
       
   195     Frame objects provide these attributes:
       
   196         f_back          next outer frame object (this frame's caller)
       
   197         f_builtins      built-in namespace seen by this frame
       
   198         f_code          code object being executed in this frame
       
   199         f_exc_traceback traceback if raised in this frame, or None
       
   200         f_exc_type      exception type if raised in this frame, or None
       
   201         f_exc_value     exception value if raised in this frame, or None
       
   202         f_globals       global namespace seen by this frame
       
   203         f_lasti         index of last attempted instruction in bytecode
       
   204         f_lineno        current line number in Python source code
       
   205         f_locals        local namespace seen by this frame
       
   206         f_restricted    0 or 1 if frame is in restricted execution mode
       
   207         f_trace         tracing function for this frame, or None"""
       
   208     return isinstance(object, types.FrameType)
       
   209 
       
   210 def iscode(object):
       
   211     """Return true if the object is a code object.
       
   212 
       
   213     Code objects provide these attributes:
       
   214         co_argcount     number of arguments (not including * or ** args)
       
   215         co_code         string of raw compiled bytecode
       
   216         co_consts       tuple of constants used in the bytecode
       
   217         co_filename     name of file in which this code object was created
       
   218         co_firstlineno  number of first line in Python source code
       
   219         co_flags        bitmap: 1=optimized | 2=newlocals | 4=*arg | 8=**arg
       
   220         co_lnotab       encoded mapping of line numbers to bytecode indices
       
   221         co_name         name with which this code object was defined
       
   222         co_names        tuple of names of local variables
       
   223         co_nlocals      number of local variables
       
   224         co_stacksize    virtual machine stack space required
       
   225         co_varnames     tuple of names of arguments and local variables"""
       
   226     return isinstance(object, types.CodeType)
       
   227 
       
   228 def isbuiltin(object):
       
   229     """Return true if the object is a built-in function or method.
       
   230 
       
   231     Built-in functions and methods provide these attributes:
       
   232         __doc__         documentation string
       
   233         __name__        original name of this function or method
       
   234         __self__        instance to which a method is bound, or None"""
       
   235     return isinstance(object, types.BuiltinFunctionType)
       
   236 
       
   237 def isroutine(object):
       
   238     """Return true if the object is any kind of function or method."""
       
   239     return (isbuiltin(object)
       
   240             or isfunction(object)
       
   241             or ismethod(object)
       
   242             or ismethoddescriptor(object))
       
   243 
       
   244 def isgenerator(object):
       
   245     """Return true if the object is a generator object."""
       
   246     return isinstance(object, types.GeneratorType)
       
   247 
       
   248 def isabstract(object):
       
   249     """Return true if the object is an abstract base class (ABC)."""
       
   250     return isinstance(object, type) and object.__flags__ & TPFLAGS_IS_ABSTRACT
       
   251 
       
   252 def getmembers(object, predicate=None):
       
   253     """Return all members of an object as (name, value) pairs sorted by name.
       
   254     Optionally, only return members that satisfy a given predicate."""
       
   255     results = []
       
   256     for key in dir(object):
       
   257         value = getattr(object, key)
       
   258         if not predicate or predicate(value):
       
   259             results.append((key, value))
       
   260     results.sort()
       
   261     return results
       
   262 
       
   263 Attribute = namedtuple('Attribute', 'name kind defining_class object')
       
   264 
       
   265 def classify_class_attrs(cls):
       
   266     """Return list of attribute-descriptor tuples.
       
   267 
       
   268     For each name in dir(cls), the return list contains a 4-tuple
       
   269     with these elements:
       
   270 
       
   271         0. The name (a string).
       
   272 
       
   273         1. The kind of attribute this is, one of these strings:
       
   274                'class method'    created via classmethod()
       
   275                'static method'   created via staticmethod()
       
   276                'property'        created via property()
       
   277                'method'          any other flavor of method
       
   278                'data'            not a method
       
   279 
       
   280         2. The class which defined this attribute (a class).
       
   281 
       
   282         3. The object as obtained directly from the defining class's
       
   283            __dict__, not via getattr.  This is especially important for
       
   284            data attributes:  C.data is just a data object, but
       
   285            C.__dict__['data'] may be a data descriptor with additional
       
   286            info, like a __doc__ string.
       
   287     """
       
   288 
       
   289     mro = getmro(cls)
       
   290     names = dir(cls)
       
   291     result = []
       
   292     for name in names:
       
   293         # Get the object associated with the name.
       
   294         # Getting an obj from the __dict__ sometimes reveals more than
       
   295         # using getattr.  Static and class methods are dramatic examples.
       
   296         if name in cls.__dict__:
       
   297             obj = cls.__dict__[name]
       
   298         else:
       
   299             obj = getattr(cls, name)
       
   300 
       
   301         # Figure out where it was defined.
       
   302         homecls = getattr(obj, "__objclass__", None)
       
   303         if homecls is None:
       
   304             # search the dicts.
       
   305             for base in mro:
       
   306                 if name in base.__dict__:
       
   307                     homecls = base
       
   308                     break
       
   309 
       
   310         # Get the object again, in order to get it from the defining
       
   311         # __dict__ instead of via getattr (if possible).
       
   312         if homecls is not None and name in homecls.__dict__:
       
   313             obj = homecls.__dict__[name]
       
   314 
       
   315         # Also get the object via getattr.
       
   316         obj_via_getattr = getattr(cls, name)
       
   317 
       
   318         # Classify the object.
       
   319         if isinstance(obj, staticmethod):
       
   320             kind = "static method"
       
   321         elif isinstance(obj, classmethod):
       
   322             kind = "class method"
       
   323         elif isinstance(obj, property):
       
   324             kind = "property"
       
   325         elif (ismethod(obj_via_getattr) or
       
   326               ismethoddescriptor(obj_via_getattr)):
       
   327             kind = "method"
       
   328         else:
       
   329             kind = "data"
       
   330 
       
   331         result.append(Attribute(name, kind, homecls, obj))
       
   332 
       
   333     return result
       
   334 
       
   335 # ----------------------------------------------------------- class helpers
       
   336 def _searchbases(cls, accum):
       
   337     # Simulate the "classic class" search order.
       
   338     if cls in accum:
       
   339         return
       
   340     accum.append(cls)
       
   341     for base in cls.__bases__:
       
   342         _searchbases(base, accum)
       
   343 
       
   344 def getmro(cls):
       
   345     "Return tuple of base classes (including cls) in method resolution order."
       
   346     if hasattr(cls, "__mro__"):
       
   347         return cls.__mro__
       
   348     else:
       
   349         result = []
       
   350         _searchbases(cls, result)
       
   351         return tuple(result)
       
   352 
       
   353 # -------------------------------------------------- source code extraction
       
   354 def indentsize(line):
       
   355     """Return the indent size, in spaces, at the start of a line of text."""
       
   356     expline = string.expandtabs(line)
       
   357     return len(expline) - len(string.lstrip(expline))
       
   358 
       
   359 def getdoc(object):
       
   360     """Get the documentation string for an object.
       
   361 
       
   362     All tabs are expanded to spaces.  To clean up docstrings that are
       
   363     indented to line up with blocks of code, any whitespace than can be
       
   364     uniformly removed from the second line onwards is removed."""
       
   365     try:
       
   366         doc = object.__doc__
       
   367     except AttributeError:
       
   368         return None
       
   369     if not isinstance(doc, types.StringTypes):
       
   370         return None
       
   371     return cleandoc(doc)
       
   372 
       
   373 def cleandoc(doc):
       
   374     """Clean up indentation from docstrings.
       
   375 
       
   376     Any whitespace that can be uniformly removed from the second line
       
   377     onwards is removed."""
       
   378     try:
       
   379         lines = string.split(string.expandtabs(doc), '\n')
       
   380     except UnicodeError:
       
   381         return None
       
   382     else:
       
   383         # Find minimum indentation of any non-blank lines after first line.
       
   384         margin = sys.maxint
       
   385         for line in lines[1:]:
       
   386             content = len(string.lstrip(line))
       
   387             if content:
       
   388                 indent = len(line) - content
       
   389                 margin = min(margin, indent)
       
   390         # Remove indentation.
       
   391         if lines:
       
   392             lines[0] = lines[0].lstrip()
       
   393         if margin < sys.maxint:
       
   394             for i in range(1, len(lines)): lines[i] = lines[i][margin:]
       
   395         # Remove any trailing or leading blank lines.
       
   396         while lines and not lines[-1]:
       
   397             lines.pop()
       
   398         while lines and not lines[0]:
       
   399             lines.pop(0)
       
   400         return string.join(lines, '\n')
       
   401 
       
   402 def getfile(object):
       
   403     """Work out which source or compiled file an object was defined in."""
       
   404     if ismodule(object):
       
   405         if hasattr(object, '__file__'):
       
   406             return object.__file__
       
   407         raise TypeError('arg is a built-in module')
       
   408     if isclass(object):
       
   409         object = sys.modules.get(object.__module__)
       
   410         if hasattr(object, '__file__'):
       
   411             return object.__file__
       
   412         raise TypeError('arg is a built-in class')
       
   413     if ismethod(object):
       
   414         object = object.im_func
       
   415     if isfunction(object):
       
   416         object = object.func_code
       
   417     if istraceback(object):
       
   418         object = object.tb_frame
       
   419     if isframe(object):
       
   420         object = object.f_code
       
   421     if iscode(object):
       
   422         return object.co_filename
       
   423     raise TypeError('arg is not a module, class, method, '
       
   424                     'function, traceback, frame, or code object')
       
   425 
       
   426 ModuleInfo = namedtuple('ModuleInfo', 'name suffix mode module_type')
       
   427 
       
   428 def getmoduleinfo(path):
       
   429     """Get the module name, suffix, mode, and module type for a given file."""
       
   430     filename = os.path.basename(path)
       
   431     suffixes = map(lambda info:
       
   432                    (-len(info[0]), info[0], info[1], info[2]),
       
   433                     imp.get_suffixes())
       
   434     suffixes.sort() # try longest suffixes first, in case they overlap
       
   435     for neglen, suffix, mode, mtype in suffixes:
       
   436         if filename[neglen:] == suffix:
       
   437             return ModuleInfo(filename[:neglen], suffix, mode, mtype)
       
   438 
       
   439 def getmodulename(path):
       
   440     """Return the module name for a given file, or None."""
       
   441     info = getmoduleinfo(path)
       
   442     if info: return info[0]
       
   443 
       
   444 def getsourcefile(object):
       
   445     """Return the Python source file an object was defined in, if it exists."""
       
   446     filename = getfile(object)
       
   447     if string.lower(filename[-4:]) in ('.pyc', '.pyo'):
       
   448         filename = filename[:-4] + '.py'
       
   449     for suffix, mode, kind in imp.get_suffixes():
       
   450         if 'b' in mode and string.lower(filename[-len(suffix):]) == suffix:
       
   451             # Looks like a binary file.  We want to only return a text file.
       
   452             return None
       
   453     if os.path.exists(filename):
       
   454         return filename
       
   455     # only return a non-existent filename if the module has a PEP 302 loader
       
   456     if hasattr(getmodule(object, filename), '__loader__'):
       
   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     file = getsourcefile(object) or getfile(object)
       
   525     module = getmodule(object, file)
       
   526     if module:
       
   527         lines = linecache.getlines(file, module.__dict__)
       
   528     else:
       
   529         lines = linecache.getlines(file)
       
   530     if not lines:
       
   531         raise IOError('could not get source code')
       
   532 
       
   533     if ismodule(object):
       
   534         return lines, 0
       
   535 
       
   536     if isclass(object):
       
   537         name = object.__name__
       
   538         pat = re.compile(r'^(\s*)class\s*' + name + r'\b')
       
   539         # make some effort to find the best matching class definition:
       
   540         # use the one with the least indentation, which is the one
       
   541         # that's most probably not inside a function definition.
       
   542         candidates = []
       
   543         for i in range(len(lines)):
       
   544             match = pat.match(lines[i])
       
   545             if match:
       
   546                 # if it's at toplevel, it's already the best one
       
   547                 if lines[i][0] == 'c':
       
   548                     return lines, i
       
   549                 # else add whitespace to candidate list
       
   550                 candidates.append((match.group(1), i))
       
   551         if candidates:
       
   552             # this will sort by whitespace, and by line number,
       
   553             # less whitespace first
       
   554             candidates.sort()
       
   555             return lines, candidates[0][1]
       
   556         else:
       
   557             raise IOError('could not find class definition')
       
   558 
       
   559     if ismethod(object):
       
   560         object = object.im_func
       
   561     if isfunction(object):
       
   562         object = object.func_code
       
   563     if istraceback(object):
       
   564         object = object.tb_frame
       
   565     if isframe(object):
       
   566         object = object.f_code
       
   567     if iscode(object):
       
   568         if not hasattr(object, 'co_firstlineno'):
       
   569             raise IOError('could not find function definition')
       
   570         lnum = object.co_firstlineno - 1
       
   571         pat = re.compile(r'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)')
       
   572         while lnum > 0:
       
   573             if pat.match(lines[lnum]): break
       
   574             lnum = lnum - 1
       
   575         return lines, lnum
       
   576     raise IOError('could not find code object')
       
   577 
       
   578 def getcomments(object):
       
   579     """Get lines of comments immediately preceding an object's source code.
       
   580 
       
   581     Returns None when source can't be found.
       
   582     """
       
   583     try:
       
   584         lines, lnum = findsource(object)
       
   585     except (IOError, TypeError):
       
   586         return None
       
   587 
       
   588     if ismodule(object):
       
   589         # Look for a comment block at the top of the file.
       
   590         start = 0
       
   591         if lines and lines[0][:2] == '#!': start = 1
       
   592         while start < len(lines) and string.strip(lines[start]) in ('', '#'):
       
   593             start = start + 1
       
   594         if start < len(lines) and lines[start][:1] == '#':
       
   595             comments = []
       
   596             end = start
       
   597             while end < len(lines) and lines[end][:1] == '#':
       
   598                 comments.append(string.expandtabs(lines[end]))
       
   599                 end = end + 1
       
   600             return string.join(comments, '')
       
   601 
       
   602     # Look for a preceding block of comments at the same indentation.
       
   603     elif lnum > 0:
       
   604         indent = indentsize(lines[lnum])
       
   605         end = lnum - 1
       
   606         if end >= 0 and string.lstrip(lines[end])[:1] == '#' and \
       
   607             indentsize(lines[end]) == indent:
       
   608             comments = [string.lstrip(string.expandtabs(lines[end]))]
       
   609             if end > 0:
       
   610                 end = end - 1
       
   611                 comment = string.lstrip(string.expandtabs(lines[end]))
       
   612                 while comment[:1] == '#' and indentsize(lines[end]) == indent:
       
   613                     comments[:0] = [comment]
       
   614                     end = end - 1
       
   615                     if end < 0: break
       
   616                     comment = string.lstrip(string.expandtabs(lines[end]))
       
   617             while comments and string.strip(comments[0]) == '#':
       
   618                 comments[:1] = []
       
   619             while comments and string.strip(comments[-1]) == '#':
       
   620                 comments[-1:] = []
       
   621             return string.join(comments, '')
       
   622 
       
   623 class EndOfBlock(Exception): pass
       
   624 
       
   625 class BlockFinder:
       
   626     """Provide a tokeneater() method to detect the end of a code block."""
       
   627     def __init__(self):
       
   628         self.indent = 0
       
   629         self.islambda = False
       
   630         self.started = False
       
   631         self.passline = False
       
   632         self.last = 1
       
   633 
       
   634     def tokeneater(self, type, token, srow_scol, erow_ecol, line):
       
   635         srow, scol = srow_scol
       
   636         erow, ecol = erow_ecol
       
   637         if not self.started:
       
   638             # look for the first "def", "class" or "lambda"
       
   639             if token in ("def", "class", "lambda"):
       
   640                 if token == "lambda":
       
   641                     self.islambda = True
       
   642                 self.started = True
       
   643             self.passline = True    # skip to the end of the line
       
   644         elif type == tokenize.NEWLINE:
       
   645             self.passline = False   # stop skipping when a NEWLINE is seen
       
   646             self.last = srow
       
   647             if self.islambda:       # lambdas always end at the first NEWLINE
       
   648                 raise EndOfBlock
       
   649         elif self.passline:
       
   650             pass
       
   651         elif type == tokenize.INDENT:
       
   652             self.indent = self.indent + 1
       
   653             self.passline = True
       
   654         elif type == tokenize.DEDENT:
       
   655             self.indent = self.indent - 1
       
   656             # the end of matching indent/dedent pairs end a block
       
   657             # (note that this only works for "def"/"class" blocks,
       
   658             #  not e.g. for "if: else:" or "try: finally:" blocks)
       
   659             if self.indent <= 0:
       
   660                 raise EndOfBlock
       
   661         elif self.indent == 0 and type not in (tokenize.COMMENT, tokenize.NL):
       
   662             # any other token on the same indentation level end the previous
       
   663             # block as well, except the pseudo-tokens COMMENT and NL.
       
   664             raise EndOfBlock
       
   665 
       
   666 def getblock(lines):
       
   667     """Extract the block of code at the top of the given list of lines."""
       
   668     blockfinder = BlockFinder()
       
   669     try:
       
   670         tokenize.tokenize(iter(lines).next, blockfinder.tokeneater)
       
   671     except (EndOfBlock, IndentationError):
       
   672         pass
       
   673     return lines[:blockfinder.last]
       
   674 
       
   675 def getsourcelines(object):
       
   676     """Return a list of source lines and starting line number for an object.
       
   677 
       
   678     The argument may be a module, class, method, function, traceback, frame,
       
   679     or code object.  The source code is returned as a list of the lines
       
   680     corresponding to the object and the line number indicates where in the
       
   681     original source file the first line of code was found.  An IOError is
       
   682     raised if the source code cannot be retrieved."""
       
   683     lines, lnum = findsource(object)
       
   684 
       
   685     if ismodule(object): return lines, 0
       
   686     else: return getblock(lines[lnum:]), lnum + 1
       
   687 
       
   688 def getsource(object):
       
   689     """Return the text of the source code for an object.
       
   690 
       
   691     The argument may be a module, class, method, function, traceback, frame,
       
   692     or code object.  The source code is returned as a single string.  An
       
   693     IOError is raised if the source code cannot be retrieved."""
       
   694     lines, lnum = getsourcelines(object)
       
   695     return string.join(lines, '')
       
   696 
       
   697 # --------------------------------------------------- class tree extraction
       
   698 def walktree(classes, children, parent):
       
   699     """Recursive helper function for getclasstree()."""
       
   700     results = []
       
   701     classes.sort(key=attrgetter('__module__', '__name__'))
       
   702     for c in classes:
       
   703         results.append((c, c.__bases__))
       
   704         if c in children:
       
   705             results.append(walktree(children[c], children, c))
       
   706     return results
       
   707 
       
   708 def getclasstree(classes, unique=0):
       
   709     """Arrange the given list of classes into a hierarchy of nested lists.
       
   710 
       
   711     Where a nested list appears, it contains classes derived from the class
       
   712     whose entry immediately precedes the list.  Each entry is a 2-tuple
       
   713     containing a class and a tuple of its base classes.  If the 'unique'
       
   714     argument is true, exactly one entry appears in the returned structure
       
   715     for each class in the given list.  Otherwise, classes using multiple
       
   716     inheritance and their descendants will appear multiple times."""
       
   717     children = {}
       
   718     roots = []
       
   719     for c in classes:
       
   720         if c.__bases__:
       
   721             for parent in c.__bases__:
       
   722                 if not parent in children:
       
   723                     children[parent] = []
       
   724                 children[parent].append(c)
       
   725                 if unique and parent in classes: break
       
   726         elif c not in roots:
       
   727             roots.append(c)
       
   728     for parent in children:
       
   729         if parent not in classes:
       
   730             roots.append(parent)
       
   731     return walktree(roots, children, None)
       
   732 
       
   733 # ------------------------------------------------ argument list extraction
       
   734 Arguments = namedtuple('Arguments', 'args varargs keywords')
       
   735 
       
   736 def getargs(co):
       
   737     """Get information about the arguments accepted by a code object.
       
   738 
       
   739     Three things are returned: (args, varargs, varkw), where 'args' is
       
   740     a list of argument names (possibly containing nested lists), and
       
   741     'varargs' and 'varkw' are the names of the * and ** arguments or None."""
       
   742 
       
   743     if not iscode(co):
       
   744         raise TypeError('arg is not a code object')
       
   745 
       
   746     nargs = co.co_argcount
       
   747     names = co.co_varnames
       
   748     args = list(names[:nargs])
       
   749     step = 0
       
   750 
       
   751     # The following acrobatics are for anonymous (tuple) arguments.
       
   752     for i in range(nargs):
       
   753         if args[i][:1] in ('', '.'):
       
   754             stack, remain, count = [], [], []
       
   755             while step < len(co.co_code):
       
   756                 op = ord(co.co_code[step])
       
   757                 step = step + 1
       
   758                 if op >= dis.HAVE_ARGUMENT:
       
   759                     opname = dis.opname[op]
       
   760                     value = ord(co.co_code[step]) + ord(co.co_code[step+1])*256
       
   761                     step = step + 2
       
   762                     if opname in ('UNPACK_TUPLE', 'UNPACK_SEQUENCE'):
       
   763                         remain.append(value)
       
   764                         count.append(value)
       
   765                     elif opname == 'STORE_FAST':
       
   766                         stack.append(names[value])
       
   767 
       
   768                         # Special case for sublists of length 1: def foo((bar))
       
   769                         # doesn't generate the UNPACK_TUPLE bytecode, so if
       
   770                         # `remain` is empty here, we have such a sublist.
       
   771                         if not remain:
       
   772                             stack[0] = [stack[0]]
       
   773                             break
       
   774                         else:
       
   775                             remain[-1] = remain[-1] - 1
       
   776                             while remain[-1] == 0:
       
   777                                 remain.pop()
       
   778                                 size = count.pop()
       
   779                                 stack[-size:] = [stack[-size:]]
       
   780                                 if not remain: break
       
   781                                 remain[-1] = remain[-1] - 1
       
   782                             if not remain: break
       
   783             args[i] = stack[0]
       
   784 
       
   785     varargs = None
       
   786     if co.co_flags & CO_VARARGS:
       
   787         varargs = co.co_varnames[nargs]
       
   788         nargs = nargs + 1
       
   789     varkw = None
       
   790     if co.co_flags & CO_VARKEYWORDS:
       
   791         varkw = co.co_varnames[nargs]
       
   792     return Arguments(args, varargs, varkw)
       
   793 
       
   794 ArgSpec = namedtuple('ArgSpec', 'args varargs keywords defaults')
       
   795 
       
   796 def getargspec(func):
       
   797     """Get the names and default values of a function's arguments.
       
   798 
       
   799     A tuple of four things is returned: (args, varargs, varkw, defaults).
       
   800     'args' is a list of the argument names (it may contain nested lists).
       
   801     'varargs' and 'varkw' are the names of the * and ** arguments or None.
       
   802     'defaults' is an n-tuple of the default values of the last n arguments.
       
   803     """
       
   804 
       
   805     if ismethod(func):
       
   806         func = func.im_func
       
   807     if not isfunction(func):
       
   808         raise TypeError('arg is not a Python function')
       
   809     args, varargs, varkw = getargs(func.func_code)
       
   810     return ArgSpec(args, varargs, varkw, func.func_defaults)
       
   811 
       
   812 ArgInfo = namedtuple('ArgInfo', 'args varargs keywords locals')
       
   813 
       
   814 def getargvalues(frame):
       
   815     """Get information about arguments passed into a particular frame.
       
   816 
       
   817     A tuple of four things is returned: (args, varargs, varkw, locals).
       
   818     'args' is a list of the argument names (it may contain nested lists).
       
   819     'varargs' and 'varkw' are the names of the * and ** arguments or None.
       
   820     'locals' is the locals dictionary of the given frame."""
       
   821     args, varargs, varkw = getargs(frame.f_code)
       
   822     return ArgInfo(args, varargs, varkw, frame.f_locals)
       
   823 
       
   824 def joinseq(seq):
       
   825     if len(seq) == 1:
       
   826         return '(' + seq[0] + ',)'
       
   827     else:
       
   828         return '(' + string.join(seq, ', ') + ')'
       
   829 
       
   830 def strseq(object, convert, join=joinseq):
       
   831     """Recursively walk a sequence, stringifying each element."""
       
   832     if type(object) in (list, tuple):
       
   833         return join(map(lambda o, c=convert, j=join: strseq(o, c, j), object))
       
   834     else:
       
   835         return convert(object)
       
   836 
       
   837 def formatargspec(args, varargs=None, varkw=None, defaults=None,
       
   838                   formatarg=str,
       
   839                   formatvarargs=lambda name: '*' + name,
       
   840                   formatvarkw=lambda name: '**' + name,
       
   841                   formatvalue=lambda value: '=' + repr(value),
       
   842                   join=joinseq):
       
   843     """Format an argument spec from the 4 values returned by getargspec.
       
   844 
       
   845     The first four arguments are (args, varargs, varkw, defaults).  The
       
   846     other four arguments are the corresponding optional formatting functions
       
   847     that are called to turn names and values into strings.  The ninth
       
   848     argument is an optional function to format the sequence of arguments."""
       
   849     specs = []
       
   850     if defaults:
       
   851         firstdefault = len(args) - len(defaults)
       
   852     for i in range(len(args)):
       
   853         spec = strseq(args[i], formatarg, join)
       
   854         if defaults and i >= firstdefault:
       
   855             spec = spec + formatvalue(defaults[i - firstdefault])
       
   856         specs.append(spec)
       
   857     if varargs is not None:
       
   858         specs.append(formatvarargs(varargs))
       
   859     if varkw is not None:
       
   860         specs.append(formatvarkw(varkw))
       
   861     return '(' + string.join(specs, ', ') + ')'
       
   862 
       
   863 def formatargvalues(args, varargs, varkw, locals,
       
   864                     formatarg=str,
       
   865                     formatvarargs=lambda name: '*' + name,
       
   866                     formatvarkw=lambda name: '**' + name,
       
   867                     formatvalue=lambda value: '=' + repr(value),
       
   868                     join=joinseq):
       
   869     """Format an argument spec from the 4 values returned by getargvalues.
       
   870 
       
   871     The first four arguments are (args, varargs, varkw, locals).  The
       
   872     next four arguments are the corresponding optional formatting functions
       
   873     that are called to turn names and values into strings.  The ninth
       
   874     argument is an optional function to format the sequence of arguments."""
       
   875     def convert(name, locals=locals,
       
   876                 formatarg=formatarg, formatvalue=formatvalue):
       
   877         return formatarg(name) + formatvalue(locals[name])
       
   878     specs = []
       
   879     for i in range(len(args)):
       
   880         specs.append(strseq(args[i], convert, join))
       
   881     if varargs:
       
   882         specs.append(formatvarargs(varargs) + formatvalue(locals[varargs]))
       
   883     if varkw:
       
   884         specs.append(formatvarkw(varkw) + formatvalue(locals[varkw]))
       
   885     return '(' + string.join(specs, ', ') + ')'
       
   886 
       
   887 # -------------------------------------------------- stack frame extraction
       
   888 
       
   889 Traceback = namedtuple('Traceback', 'filename lineno function code_context index')
       
   890 
       
   891 def getframeinfo(frame, context=1):
       
   892     """Get information about a frame or traceback object.
       
   893 
       
   894     A tuple of five things is returned: the filename, the line number of
       
   895     the current line, the function name, a list of lines of context from
       
   896     the source code, and the index of the current line within that list.
       
   897     The optional second argument specifies the number of lines of context
       
   898     to return, which are centered around the current line."""
       
   899     if istraceback(frame):
       
   900         lineno = frame.tb_lineno
       
   901         frame = frame.tb_frame
       
   902     else:
       
   903         lineno = frame.f_lineno
       
   904     if not isframe(frame):
       
   905         raise TypeError('arg is not a frame or traceback object')
       
   906 
       
   907     filename = getsourcefile(frame) or getfile(frame)
       
   908     if context > 0:
       
   909         start = lineno - 1 - context//2
       
   910         try:
       
   911             lines, lnum = findsource(frame)
       
   912         except IOError:
       
   913             lines = index = None
       
   914         else:
       
   915             start = max(start, 1)
       
   916             start = max(0, min(start, len(lines) - context))
       
   917             lines = lines[start:start+context]
       
   918             index = lineno - 1 - start
       
   919     else:
       
   920         lines = index = None
       
   921 
       
   922     return Traceback(filename, lineno, frame.f_code.co_name, lines, index)
       
   923 
       
   924 def getlineno(frame):
       
   925     """Get the line number from a frame object, allowing for optimization."""
       
   926     # FrameType.f_lineno is now a descriptor that grovels co_lnotab
       
   927     return frame.f_lineno
       
   928 
       
   929 def getouterframes(frame, context=1):
       
   930     """Get a list of records for a frame and all higher (calling) frames.
       
   931 
       
   932     Each record contains a frame object, filename, line number, function
       
   933     name, a list of lines of context, and index within the context."""
       
   934     framelist = []
       
   935     while frame:
       
   936         framelist.append((frame,) + getframeinfo(frame, context))
       
   937         frame = frame.f_back
       
   938     return framelist
       
   939 
       
   940 def getinnerframes(tb, context=1):
       
   941     """Get a list of records for a traceback's frame and all lower frames.
       
   942 
       
   943     Each record contains a frame object, filename, line number, function
       
   944     name, a list of lines of context, and index within the context."""
       
   945     framelist = []
       
   946     while tb:
       
   947         framelist.append((tb.tb_frame,) + getframeinfo(tb, context))
       
   948         tb = tb.tb_next
       
   949     return framelist
       
   950 
       
   951 currentframe = sys._getframe
       
   952 
       
   953 def stack(context=1):
       
   954     """Return a list of records for the stack above the caller's frame."""
       
   955     return getouterframes(sys._getframe(1), context)
       
   956 
       
   957 def trace(context=1):
       
   958     """Return a list of records for the stack below the current exception."""
       
   959     return getinnerframes(sys.exc_info()[2], context)