| """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 <ping@lfw.org>' |
| __date__ = '1 Jan 2001' |
| |
| import sys, os, types, string, re, dis, imp, tokenize |
| |
| # ----------------------------------------------------------- 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 type(object) is 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 type(object) is 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 type(object) is types.MethodType |
| |
| 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 type(object) in [types.FunctionType, types.LambdaType] |
| |
| 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 type(object) is 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 type(object) is 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 type(object) is 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 type(object) in [types.BuiltinFunctionType, |
| types.BuiltinMethodType] |
| |
| def isroutine(object): |
| """Return true if the object is any kind of function or method.""" |
| return type(object) in [types.FunctionType, types.LambdaType, |
| types.MethodType, types.BuiltinFunctionType, |
| types.BuiltinMethodType] |
| |
| 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 |
| |
| # -------------------------------------------------- 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.""" |
| if hasattr(object, '__doc__') and object.__doc__: |
| lines = string.split(string.expandtabs(object.__doc__), '\n') |
| margin = None |
| for line in lines[1:]: |
| content = len(string.lstrip(line)) |
| if not content: continue |
| indent = len(line) - content |
| if margin is None: margin = indent |
| else: margin = min(margin, indent) |
| if margin is not None: |
| for i in range(1, len(lines)): lines[i] = lines[i][margin:] |
| 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[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 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 isclass(object): |
| return sys.modules.get(object.__module__) |
| try: |
| file = getabsfile(object) |
| except TypeError: |
| return None |
| if modulesbyfile.has_key(file): |
| return sys.modules[modulesbyfile[file]] |
| for module in sys.modules.values(): |
| if hasattr(module, '__file__'): |
| modulesbyfile[getabsfile(module)] = module.__name__ |
| if modulesbyfile.has_key(file): |
| return sys.modules[modulesbyfile[file]] |
| main = sys.modules['__main__'] |
| 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.""" |
| try: |
| file = open(getsourcefile(object)) |
| except (TypeError, IOError): |
| raise IOError, 'could not get source code' |
| lines = file.readlines() |
| file.close() |
| |
| 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') |
| while lnum > 0: |
| if pat.match(lines[lnum]): break |
| lnum = lnum - 1 |
| return lines, lnum |
| |
| def getcomments(object): |
| """Get lines of comments immediately preceding an object's source code.""" |
| try: lines, lnum = findsource(object) |
| except IOError: return None |
| |
| if ismodule(object): |
| # Look for a comment block at the top of the file. |
| start = 0 |
| if lines[0][:2] == '#!': start = 1 |
| while start < len(lines) and string.strip(lines[start]) in ['', '#']: |
| start = start + 1 |
| if 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 |
| |
| 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]] |
| |
| 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(lambda a, b: cmp(a.__name__, b.__name__)) |
| for c in classes: |
| results.append((c, c.__bases__)) |
| if children.has_key(c): |
| 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 children.has_key(parent): |
| 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.keys(): |
| 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 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: |
| specs.append(formatvarargs(varargs)) |
| if varkw: |
| 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): |
| frame = frame.tb_frame |
| if not isframe(frame): |
| raise TypeError, 'arg is not a frame or traceback object' |
| |
| filename = getsourcefile(frame) |
| lineno = getlineno(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 = 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.""" |
| # Written by Marc-André Lemburg; revised by Jim Hugunin and Fredrik Lundh. |
| lineno = frame.f_lineno |
| code = frame.f_code |
| if hasattr(code, 'co_lnotab'): |
| table = code.co_lnotab |
| lineno = code.co_firstlineno |
| addr = 0 |
| for i in range(0, len(table), 2): |
| addr = addr + ord(table[i]) |
| if addr > frame.f_lasti: break |
| lineno = lineno + ord(table[i+1]) |
| return 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.""" |
| tb = tb.tb_next |
| framelist = [] |
| while tb: |
| framelist.append((tb.tb_frame,) + getframeinfo(tb, context)) |
| tb = tb.tb_next |
| return framelist |
| |
| def currentframe(): |
| """Return the frame object for the caller's stack frame.""" |
| try: |
| raise 'catch me' |
| except: |
| return sys.exc_traceback.tb_frame.f_back |
| |
| if hasattr(sys, '_getframe'): currentframe = sys._getframe |
| |
| def stack(context=1): |
| """Return a list of records for the stack above the caller's frame.""" |
| return getouterframes(currentframe().f_back, context) |
| |
| def trace(context=1): |
| """Return a list of records for the stack below the current exception.""" |
| return getinnerframes(sys.exc_traceback, context) |