# -*- 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(), 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() - 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 ' __date__ = '1 Jan 2001' import sys, os, types, string, re, dis, imp, tokenize, linecache from operator import attrgetter # ----------------------------------------------------------- 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, types.ClassType) or hasattr(object, '__bases__') 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__")) 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 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 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): value = getattr(object, key) if not predicate or predicate(value): results.append((key, value)) results.sort() return results 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. # Getting an obj from the __dict__ sometimes reveals more than # using getattr. Static and class methods are dramatic examples. if name in cls.__dict__: obj = cls.__dict__[name] else: obj = getattr(cls, name) # Figure out where it was defined. homecls = getattr(obj, "__objclass__", None) if homecls is None: # search the dicts. for base in mro: if name in base.__dict__: homecls = base break # Get the object again, in order to get it from the defining # __dict__ instead of via getattr (if possible). if homecls is not None and name in homecls.__dict__: obj = homecls.__dict__[name] # Also get the object via getattr. obj_via_getattr = getattr(cls, name) # Classify the object. if isinstance(obj, staticmethod): kind = "static method" elif isinstance(obj, classmethod): kind = "class method" elif isinstance(obj, property): kind = "property" elif (ismethod(obj_via_getattr) or ismethoddescriptor(obj_via_getattr)): kind = "method" else: kind = "data" result.append((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 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('arg is a built-in module') if isclass(object): object = sys.modules.get(object.__module__) if hasattr(object, '__file__'): return object.__file__ raise TypeError('arg is a built-in class') 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('arg is not a module, class, method, ' 'function, traceback, frame, or code object') def getmoduleinfo(path): """Get the module name, suffix, mode, and module type for a given file.""" filename = os.path.basename(path) suffixes = map(lambda (suffix, mode, mtype): (-len(suffix), suffix, mode, mtype), 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 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 Python source file an object was defined in, if it exists.""" 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 def getabsfile(object): """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.""" return os.path.normcase( os.path.abspath(getsourcefile(object) or getfile(object))) modulesbyfile = {} def getmodule(object): """Return the module an object was defined in, or None if not found.""" if ismodule(object): return object if isclass(object): return sys.modules.get(object.__module__) try: file = getabsfile(object) except TypeError: return None if file in modulesbyfile: return sys.modules.get(modulesbyfile[file]) for module in sys.modules.values(): if hasattr(module, '__file__'): modulesbyfile[ os.path.realpath( getabsfile(module))] = module.__name__ if file in modulesbyfile: return sys.modules.get(modulesbyfile[file]) 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 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 = getsourcefile(object) or getfile(object) 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') for i in range(len(lines)): if pat.match(lines[i]): return lines, i 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)|(.*\slambda(:|\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 ListReader: """Provide a readline() method to return lines from a list of strings.""" def __init__(self, lines): self.lines = lines self.index = 0 def readline(self): i = self.index if i < len(self.lines): self.index = i + 1 return self.lines[i] else: return '' 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.started = 0 self.last = 0 def tokeneater(self, type, token, (srow, scol), (erow, ecol), line): if not self.started: if type == tokenize.NAME: self.started = 1 elif type == tokenize.NEWLINE: self.last = srow elif type == tokenize.INDENT: self.indent = self.indent + 1 elif type == tokenize.DEDENT: self.indent = self.indent - 1 if self.indent == 0: raise EndOfBlock, self.last elif type == tokenize.NAME and scol == 0: raise EndOfBlock, self.last def getblock(lines): """Extract the block of code at the top of the given list of lines.""" try: tokenize.tokenize(ListReader(lines).readline, BlockFinder().tokeneater) except EndOfBlock, eob: return lines[:eob.args[0]] # Fooling the indent/dedent logic implies a one-line definition return lines[:1] 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('__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] = [] 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 # These constants are from Python's compile.h. CO_OPTIMIZED, CO_NEWLOCALS, CO_VARARGS, CO_VARKEYWORDS = 1, 2, 4, 8 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('arg is not a code object') code = co.co_code 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(code): op = ord(code[step]) step = step + 1 if op >= dis.HAVE_ARGUMENT: opname = dis.opname[op] value = ord(code[step]) + ord(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]) 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 args, varargs, varkw 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('arg is not a Python function') args, varargs, varkw = getargs(func.func_code) return args, varargs, varkw, func.func_defaults 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 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 [types.ListType, types.TupleType]: 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 in range(len(args)): spec = strseq(args[i], 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, ', ') + ')' # -------------------------------------------------- stack frame extraction 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('arg is not a frame or traceback object') 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 (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 currentframe = sys._getframe 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)