bpython/bpython/inspection.py at main · kroy-dev/bpython · GitHub

History

372 lines (314 loc) · 12.2 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

# The MIT License

# Permission is hereby granted, free of charge, to any person obtaining a copy

# of this software and associated documentation files (the "Software"), to deal

# in the Software without restriction, including without limitation the rights

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

# copies of the Software, and to permit persons to whom the Software is

# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in

# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

# THE SOFTWARE.

import inspect

import keyword

import pydoc

import re

from dataclasses import dataclass

from typing import Any, Callable, Optional, Type, Dict, List, ContextManager

from types import MemberDescriptorType, TracebackType

from ._typing_compat import Literal

from pygments.token import Token

from pygments.lexers import Python3Lexer

from .lazyre import LazyReCompile

@dataclass

class ArgSpec:

args: List[str]

varargs: Optional[str]

varkwargs: Optional[str]

defaults: Optional[List[Any]]

kwonly: List[str]

kwonly_defaults: Optional[Dict[str, Any]]

annotations: Optional[Dict[str, Any]]

@dataclass

class FuncProps:

func: str

argspec: ArgSpec

is_bound_method: bool

class AttrCleaner(ContextManager[None]):

"""A context manager that tries to make an object not exhibit side-effects

on attribute lookup.

Unless explicitly required, prefer `getattr_safe`."""

def __init__(self, obj: Any) -> None:

self._obj = obj

def __enter__(self) -> None:

"""Try to make an object not exhibit side-effects on attribute

lookup."""

type_ = type(self._obj)

# Dark magic:

# If __getattribute__ doesn't exist on the class and __getattr__ does

# then __getattr__ will be called when doing

# getattr(type_, '__getattribute__', None)

# so we need to first remove the __getattr__, then the

# __getattribute__, then look up the attributes and then restore the

# original methods. :-(

# The upshot being that introspecting on an object to display its

# attributes will avoid unwanted side-effects.

__getattr__ = getattr(type_, "__getattr__", None)

if __getattr__ is not None:

try:

setattr(type_, "__getattr__", (lambda *_, **__: None))

except TypeError:

__getattr__ = None

__getattribute__ = getattr(type_, "__getattribute__", None)

if __getattribute__ is not None:

try:

setattr(type_, "__getattribute__", object.__getattribute__)

except TypeError:

# XXX: This happens for e.g. built-in types

__getattribute__ = None

self._attribs = (__getattribute__, __getattr__)

# /Dark magic

def __exit__(

self,

exc_type: Optional[Type[BaseException]],

exc_val: Optional[BaseException],

exc_tb: Optional[TracebackType],

) -> Literal[False]:

"""Restore an object's magic methods."""

type_ = type(self._obj)

__getattribute__, __getattr__ = self._attribs

# Dark magic:

if __getattribute__ is not None:

setattr(type_, "__getattribute__", __getattribute__)

if __getattr__ is not None:

setattr(type_, "__getattr__", __getattr__)

# /Dark magic

return False

class _Repr:

"""

Helper for `fixlongargs()`: Returns the given value in `__repr__()`.

"""

def __init__(self, value: str) -> None:

self.value = value

def __repr__(self) -> str:

return self.value

__str__ = __repr__

def parsekeywordpairs(signature: str) -> Dict[str, str]:

preamble = True

stack = []

substack: List[str] = []

parendepth = 0

annotation = False

for token, value in Python3Lexer().get_tokens(signature):

if preamble:

if token is Token.Punctuation and value == "(":

# First "(" starts the list of arguments

preamble = False

continue

if token is Token.Punctuation:

if value in "({[":

parendepth += 1

elif value in ")}]":

parendepth -= 1

elif value == ":":

if parendepth == -1:

# End of signature reached

break

elif parendepth == 0:

# Start of type annotation

annotation = True

if (value, parendepth) in ((",", 0), (")", -1)):

# End of current argument

stack.append(substack)

substack = []

# If type annotation didn't end before, it does now.

annotation = False

continue

elif token is Token.Operator and value == "=" and parendepth == 0:

# End of type annotation

annotation = False

if value and not annotation and (parendepth > 0 or value.strip()):

substack.append(value)

return {item[0]: "".join(item[2:]) for item in stack if len(item) >= 3}

def _fixlongargs(f: Callable, argspec: ArgSpec) -> ArgSpec:

"""Functions taking default arguments that are references to other objects

whose str() is too big will cause breakage, so we swap out the object

itself with the name it was referenced with in the source by parsing the

source itself !"""

if argspec.defaults is None:

# No keyword args, no need to do anything

return argspec

values = list(argspec.defaults)

if not values:

return argspec

keys = argspec.args[-len(values) :]

try:

src = inspect.getsourcelines(f)

except (OSError, IndexError):

# IndexError is raised in inspect.findsource(), can happen in

# some situations. See issue #94.

return argspec

kwparsed = parsekeywordpairs("".join(src[0]))

for i, (key, value) in enumerate(zip(keys, values)):

if len(repr(value)) != len(kwparsed[key]):

values[i] = _Repr(kwparsed[key])

argspec.defaults = values

return argspec

_getpydocspec_re = LazyReCompile(

r"([a-zA-Z_][a-zA-Z0-9_]*?)$(.*?)$", re.DOTALL

)

def _getpydocspec(f: Callable) -> Optional[ArgSpec]:

try:

argspec = pydoc.getdoc(f)

except NameError:

return None

s = _getpydocspec_re.search(argspec)

if s is None:

return None

if not hasattr_safe(f, "__name__") or s.groups()[0] != f.__name__:

return None

args = []

defaults = []

varargs = varkwargs = None

kwonly_args = []

kwonly_defaults = {}

for arg in s.group(2).split(","):

arg = arg.strip()

if arg.startswith("**"):

varkwargs = arg[2:]

elif arg.startswith("*"):

varargs = arg[1:]

elif arg == "...":

# At least print denotes "..." as separator between varargs and kwonly args.

varargs = ""

else:

arg, _, default = arg.partition("=")

if varargs is not None:

kwonly_args.append(arg)

if default:

kwonly_defaults[arg] = default

else:

args.append(arg)

if default:

defaults.append(default)

return ArgSpec(

args, varargs, varkwargs, defaults, kwonly_args, kwonly_defaults, None

)

def getfuncprops(func: str, f: Callable) -> Optional[FuncProps]:

# Check if it's a real bound method or if it's implicitly calling __init__

# (i.e. FooClass(...) and not FooClass.__init__(...) -- the former would

# not take 'self', the latter would:

try:

func_name = getattr(f, "__name__", None)

except:

# if calling foo.__name__ would result in an error

func_name = None

try:

is_bound_method = (

(inspect.ismethod(f) and f.__self__ is not None)

or (func_name == "__init__" and not func.endswith(".__init__"))

or (func_name == "__new__" and not func.endswith(".__new__"))

)

except:

# if f is a method from a xmlrpclib.Server instance, func_name ==

# '__init__' throws xmlrpclib.Fault (see #202)

return None

try:

argspec = _get_argspec_from_signature(f)

fprops = FuncProps(func, _fixlongargs(f, argspec), is_bound_method)

except (TypeError, KeyError, ValueError):

argspec_pydoc = _getpydocspec(f)

if argspec_pydoc is None:

return None

if inspect.ismethoddescriptor(f):

argspec_pydoc.args.insert(0, "obj")

fprops = FuncProps(func, argspec_pydoc, is_bound_method)

return fprops

def is_eval_safe_name(string: str) -> bool:

return all(

part.isidentifier() and not keyword.iskeyword(part)

for part in string.split(".")

)

def _get_argspec_from_signature(f: Callable) -> ArgSpec:

"""Get callable signature from inspect.signature in argspec format.

inspect.signature is a Python 3 only function that returns the signature of

a function. Its advantage over inspect.getfullargspec is that it returns

the signature of a decorated function, if the wrapper function itself is

decorated with functools.wraps.

"""

args = []

varargs = varkwargs = None

defaults = []

kwonly = []

kwonly_defaults = {}

annotations = {}

signature = inspect.signature(f)

for parameter in signature.parameters.values():

if parameter.annotation is not parameter.empty:

annotations[parameter.name] = parameter.annotation

if parameter.kind == inspect.Parameter.POSITIONAL_OR_KEYWORD:

args.append(parameter.name)

if parameter.default is not parameter.empty:

defaults.append(parameter.default)

elif parameter.kind == inspect.Parameter.POSITIONAL_ONLY:

args.append(parameter.name)

elif parameter.kind == inspect.Parameter.VAR_POSITIONAL:

varargs = parameter.name

elif parameter.kind == inspect.Parameter.KEYWORD_ONLY:

kwonly.append(parameter.name)

kwonly_defaults[parameter.name] = parameter.default

elif parameter.kind == inspect.Parameter.VAR_KEYWORD:

varkwargs = parameter.name

return ArgSpec(

args,

varargs,

varkwargs,

defaults if defaults else None,

kwonly,

kwonly_defaults if kwonly_defaults else None,

annotations if annotations else None,

)

_get_encoding_line_re = LazyReCompile(r"^.*coding[:=]\s*([-\w.]+).*$")

def get_encoding(obj) -> str:

"""Try to obtain encoding information of the source of an object."""

for line in inspect.findsource(obj)[0][:2]:

m = _get_encoding_line_re.search(line)

if m:

return m.group(1)

return "utf8"

def get_encoding_file(fname: str) -> str:

"""Try to obtain encoding information from a Python source file."""

with open(fname, encoding="ascii", errors="ignore") as f:

for _ in range(2):

line = f.readline()

match = _get_encoding_line_re.search(line)

if match:

return match.group(1)

return "utf8"

def getattr_safe(obj: Any, name: str) -> Any:

"""Side effect free getattr (calls getattr_static)."""

result = inspect.getattr_static(obj, name)

# Slots are a MemberDescriptorType

if isinstance(result, MemberDescriptorType):

result = getattr(obj, name)

# classmethods are safe to access (see #966)

if isinstance(result, (classmethod, staticmethod)):

result = result.__get__(obj, obj)

return result

def hasattr_safe(obj: Any, name: str) -> bool:

try:

getattr_safe(obj, name)

return True

except AttributeError:

return False

bpython/bpython/inspection.py at main · kroy-dev/bpython · GitHub

Expand file tree

Breadcrumbs

inspection.py

Latest commit

History

Breadcrumbs

inspection.py

File metadata and controls