wxWidgets/wxPython/wx/py/introspect.py
Robin Dunn 8d9be42a28 Patch from Prabhu Ramachandran to make introspection of lazily
evaluated objects not create the final object.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@31352 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2005-01-13 21:18:17 +00:00

372 lines
13 KiB
Python

"""Provides a variety of introspective-type support functions for
things like call tips and command auto completion."""
__author__ = "Patrick K. O'Brien <pobrien@orbtech.com>"
__cvsid__ = "$Id$"
__revision__ = "$Revision$"[11:-2]
from __future__ import nested_scopes
import cStringIO
import inspect
import sys
import tokenize
import types
def getAutoCompleteList(command='', locals=None, includeMagic=1,
includeSingle=1, includeDouble=1):
"""Return list of auto-completion options for command.
The list of options will be based on the locals namespace."""
attributes = []
# Get the proper chunk of code from the command.
root = getRoot(command, terminator='.')
try:
if locals is not None:
object = eval(root, locals)
else:
object = eval(root)
except:
pass
else:
attributes = getAttributeNames(object, includeMagic,
includeSingle, includeDouble)
return attributes
def getAttributeNames(object, includeMagic=1, includeSingle=1,
includeDouble=1):
"""Return list of unique attributes, including inherited, for object."""
attributes = []
dict = {}
if not hasattrAlwaysReturnsTrue(object):
# Add some attributes that don't always get picked up.
special_attrs = ['__bases__', '__class__', '__dict__', '__name__',
'func_closure', 'func_code', 'func_defaults',
'func_dict', 'func_doc', 'func_globals', 'func_name']
attributes += [attr for attr in special_attrs \
if hasattr(object, attr)]
if includeMagic:
try: attributes += object._getAttributeNames()
except: pass
# Get all attribute names.
attrdict = getAllAttributeNames(object)
# Store the object's dir.
object_dir = dir(object)
for (str_obj, technique, count), attrlist in attrdict.items():
# This complexity is necessary to avoid accessing all the
# attributes of the object. This is very handy for objects
# whose attributes are lazily evaluated.
if str(object) == str_obj and technique == 'dir':
attributes += attrlist
else:
attributes += [attr for attr in attrlist \
if attr not in object_dir and hasattr(object, attr)]
# Remove duplicates from the attribute list.
for item in attributes:
dict[item] = None
attributes = dict.keys()
# new-style swig wrappings can result in non-string attributes
# e.g. ITK http://www.itk.org/
attributes = [attribute for attribute in attributes \
if type(attribute) == str]
attributes.sort(lambda x, y: cmp(x.upper(), y.upper()))
if not includeSingle:
attributes = filter(lambda item: item[0]!='_' \
or item[1]=='_', attributes)
if not includeDouble:
attributes = filter(lambda item: item[:2]!='__', attributes)
return attributes
def hasattrAlwaysReturnsTrue(object):
return hasattr(object, 'bogu5_123_aTTri8ute')
def getAllAttributeNames(object):
"""Return dict of all attributes, including inherited, for an object.
Recursively walk through a class and all base classes.
"""
attrdict = {} # (object, technique, count): [list of attributes]
# !!!
# Do Not use hasattr() as a test anywhere in this function,
# because it is unreliable with remote objects: xmlrpc, soap, etc.
# They always return true for hasattr().
# !!!
try:
# Yes, this can fail if object is an instance of a class with
# __str__ (or __repr__) having a bug or raising an
# exception. :-(
key = str(object)
except:
key = 'anonymous'
# Wake up sleepy objects - a hack for ZODB objects in "ghost" state.
wakeupcall = dir(object)
del wakeupcall
# Get attributes available through the normal convention.
attributes = dir(object)
attrdict[(key, 'dir', len(attributes))] = attributes
# Get attributes from the object's dictionary, if it has one.
try:
attributes = object.__dict__.keys()
attributes.sort()
except: # Must catch all because object might have __getattr__.
pass
else:
attrdict[(key, '__dict__', len(attributes))] = attributes
# For a class instance, get the attributes for the class.
try:
klass = object.__class__
except: # Must catch all because object might have __getattr__.
pass
else:
if klass is object:
# Break a circular reference. This happens with extension
# classes.
pass
else:
attrdict.update(getAllAttributeNames(klass))
# Also get attributes from any and all parent classes.
try:
bases = object.__bases__
except: # Must catch all because object might have __getattr__.
pass
else:
if isinstance(bases, types.TupleType):
for base in bases:
if type(base) is types.TypeType:
# Break a circular reference. Happens in Python 2.2.
pass
else:
attrdict.update(getAllAttributeNames(base))
return attrdict
def getCallTip(command='', locals=None):
"""For a command, return a tuple of object name, argspec, tip text.
The call tip information will be based on the locals namespace."""
calltip = ('', '', '') # object name, argspec, tip text.
# Get the proper chunk of code from the command.
root = getRoot(command, terminator='(')
try:
if locals is not None:
object = eval(root, locals)
else:
object = eval(root)
except:
return calltip
name = ''
object, dropSelf = getBaseObject(object)
try:
name = object.__name__
except AttributeError:
pass
tip1 = ''
argspec = ''
if inspect.isbuiltin(object):
# Builtin functions don't have an argspec that we can get.
pass
elif inspect.isfunction(object):
# tip1 is a string like: "getCallTip(command='', locals=None)"
argspec = apply(inspect.formatargspec, inspect.getargspec(object))
if dropSelf:
# The first parameter to a method is a reference to an
# instance, usually coded as "self", and is usually passed
# automatically by Python; therefore we want to drop it.
temp = argspec.split(',')
if len(temp) == 1: # No other arguments.
argspec = '()'
elif temp[0][:2] == '(*': # first param is like *args, not self
pass
else: # Drop the first argument.
argspec = '(' + ','.join(temp[1:]).lstrip()
tip1 = name + argspec
doc = ''
if callable(object):
try:
doc = inspect.getdoc(object)
except:
pass
if doc:
# tip2 is the first separated line of the docstring, like:
# "Return call tip text for a command."
# tip3 is the rest of the docstring, like:
# "The call tip information will be based on ... <snip>
firstline = doc.split('\n')[0].lstrip()
if tip1 == firstline or firstline[:len(name)+1] == name+'(':
tip1 = ''
else:
tip1 += '\n\n'
docpieces = doc.split('\n\n')
tip2 = docpieces[0]
tip3 = '\n\n'.join(docpieces[1:])
tip = '%s%s\n\n%s' % (tip1, tip2, tip3)
else:
tip = tip1
calltip = (name, argspec[1:-1], tip.strip())
return calltip
def getRoot(command, terminator=None):
"""Return the rightmost root portion of an arbitrary Python command.
Return only the root portion that can be eval()'d without side
effects. The command would normally terminate with a '(' or
'.'. The terminator and anything after the terminator will be
dropped."""
command = command.split('\n')[-1]
if command.startswith(sys.ps2):
command = command[len(sys.ps2):]
command = command.lstrip()
command = rtrimTerminus(command, terminator)
tokens = getTokens(command)
if not tokens:
return ''
if tokens[-1][0] is tokenize.ENDMARKER:
# Remove the end marker.
del tokens[-1]
if not tokens:
return ''
if terminator == '.' and \
(tokens[-1][1] <> '.' or tokens[-1][0] is not tokenize.OP):
# Trap decimals in numbers, versus the dot operator.
return ''
else:
# Strip off the terminator.
if terminator and command.endswith(terminator):
size = 0 - len(terminator)
command = command[:size]
command = command.rstrip()
tokens = getTokens(command)
tokens.reverse()
line = ''
start = None
prefix = ''
laststring = '.'
emptyTypes = ('[]', '()', '{}')
for token in tokens:
tokentype = token[0]
tokenstring = token[1]
line = token[4]
if tokentype is tokenize.ENDMARKER:
continue
if tokentype in (tokenize.NAME, tokenize.STRING, tokenize.NUMBER) \
and laststring != '.':
# We've reached something that's not part of the root.
if prefix and line[token[3][1]] != ' ':
# If it doesn't have a space after it, remove the prefix.
prefix = ''
break
if tokentype in (tokenize.NAME, tokenize.STRING, tokenize.NUMBER) \
or (tokentype is tokenize.OP and tokenstring == '.'):
if prefix:
# The prefix isn't valid because it comes after a dot.
prefix = ''
break
else:
# start represents the last known good point in the line.
start = token[2][1]
elif len(tokenstring) == 1 and tokenstring in ('[({])}'):
# Remember, we're working backwords.
# So prefix += tokenstring would be wrong.
if prefix in emptyTypes and tokenstring in ('[({'):
# We've already got an empty type identified so now we
# are in a nested situation and we can break out with
# what we've got.
break
else:
prefix = tokenstring + prefix
else:
# We've reached something that's not part of the root.
break
laststring = tokenstring
if start is None:
start = len(line)
root = line[start:]
if prefix in emptyTypes:
# Empty types are safe to be eval()'d and introspected.
root = prefix + root
return root
def getTokens(command):
"""Return list of token tuples for command."""
command = str(command) # In case the command is unicode, which fails.
f = cStringIO.StringIO(command)
# tokens is a list of token tuples, each looking like:
# (type, string, (srow, scol), (erow, ecol), line)
tokens = []
# Can't use list comprehension:
# tokens = [token for token in tokenize.generate_tokens(f.readline)]
# because of need to append as much as possible before TokenError.
try:
## This code wasn't backward compatible with Python 2.1.3.
##
## for token in tokenize.generate_tokens(f.readline):
## tokens.append(token)
# This works with Python 2.1.3 (with nested_scopes).
def eater(*args):
tokens.append(args)
tokenize.tokenize_loop(f.readline, eater)
except tokenize.TokenError:
# This is due to a premature EOF, which we expect since we are
# feeding in fragments of Python code.
pass
return tokens
def rtrimTerminus(command, terminator=None):
"""Return command minus anything that follows the final terminator."""
if terminator:
pieces = command.split(terminator)
if len(pieces) > 1:
command = terminator.join(pieces[:-1]) + terminator
return command
def getBaseObject(object):
"""Return base object and dropSelf indicator for an object."""
if inspect.isbuiltin(object):
# Builtin functions don't have an argspec that we can get.
dropSelf = 0
elif inspect.ismethod(object):
# Get the function from the object otherwise
# inspect.getargspec() complains that the object isn't a
# Python function.
try:
if object.im_self is None:
# This is an unbound method so we do not drop self
# from the argspec, since an instance must be passed
# as the first arg.
dropSelf = 0
else:
dropSelf = 1
object = object.im_func
except AttributeError:
dropSelf = 0
elif inspect.isclass(object):
# Get the __init__ method function for the class.
constructor = getConstructor(object)
if constructor is not None:
object = constructor
dropSelf = 1
else:
dropSelf = 0
elif callable(object):
# Get the __call__ method instead.
try:
object = object.__call__.im_func
dropSelf = 1
except AttributeError:
dropSelf = 0
else:
dropSelf = 0
return object, dropSelf
def getConstructor(object):
"""Return constructor for class object, or None if there isn't one."""
try:
return object.__init__.im_func
except AttributeError:
for base in object.__bases__:
constructor = getConstructor(base)
if constructor is not None:
return constructor
return None