cpython/Lib/_pyrepl/_module_completer.py

389 lines
13 KiB
Python

from __future__ import annotations
import pkgutil
import sys
import token
import tokenize
from io import StringIO
from contextlib import contextmanager
from dataclasses import dataclass
from itertools import chain
from tokenize import TokenInfo
TYPE_CHECKING = False
if TYPE_CHECKING:
from typing import Any, Iterable, Iterator, Mapping
def make_default_module_completer() -> ModuleCompleter:
# Inside pyrepl, __package__ is set to None by default
return ModuleCompleter(namespace={'__package__': None})
class ModuleCompleter:
"""A completer for Python import statements.
Examples:
- import <tab>
- import foo<tab>
- import foo.<tab>
- import foo as bar, baz<tab>
- from <tab>
- from foo<tab>
- from foo import <tab>
- from foo import bar<tab>
- from foo import (bar as baz, qux<tab>
"""
def __init__(self, namespace: Mapping[str, Any] | None = None) -> None:
self.namespace = namespace or {}
self._global_cache: list[pkgutil.ModuleInfo] = []
self._curr_sys_path: list[str] = sys.path[:]
def get_completions(self, line: str) -> list[str] | None:
"""Return the next possible import completions for 'line'."""
result = ImportParser(line).parse()
if not result:
return None
try:
return self.complete(*result)
except Exception:
# Some unexpected error occurred, make it look like
# no completions are available
return []
def complete(self, from_name: str | None, name: str | None) -> list[str]:
if from_name is None:
# import x.y.z<tab>
assert name is not None
path, prefix = self.get_path_and_prefix(name)
modules = self.find_modules(path, prefix)
return [self.format_completion(path, module) for module in modules]
if name is None:
# from x.y.z<tab>
path, prefix = self.get_path_and_prefix(from_name)
modules = self.find_modules(path, prefix)
return [self.format_completion(path, module) for module in modules]
# from x.y import z<tab>
return self.find_modules(from_name, name)
def find_modules(self, path: str, prefix: str) -> list[str]:
"""Find all modules under 'path' that start with 'prefix'."""
modules = self._find_modules(path, prefix)
# Filter out invalid module names
# (for example those containing dashes that cannot be imported with 'import')
return [mod for mod in modules if mod.isidentifier()]
def _find_modules(self, path: str, prefix: str) -> list[str]:
if not path:
# Top-level import (e.g. `import foo<tab>`` or `from foo<tab>`)`
builtin_modules = [name for name in sys.builtin_module_names
if self.is_suggestion_match(name, prefix)]
third_party_modules = [module.name for module in self.global_cache
if self.is_suggestion_match(module.name, prefix)]
return sorted(builtin_modules + third_party_modules)
if path.startswith('.'):
# Convert relative path to absolute path
package = self.namespace.get('__package__', '')
path = self.resolve_relative_name(path, package) # type: ignore[assignment]
if path is None:
return []
modules: Iterable[pkgutil.ModuleInfo] = self.global_cache
for segment in path.split('.'):
modules = [mod_info for mod_info in modules
if mod_info.ispkg and mod_info.name == segment]
modules = self.iter_submodules(modules)
return [module.name for module in modules
if self.is_suggestion_match(module.name, prefix)]
def is_suggestion_match(self, module_name: str, prefix: str) -> bool:
if prefix:
return module_name.startswith(prefix)
# For consistency with attribute completion, which
# does not suggest private attributes unless requested.
return not module_name.startswith("_")
def iter_submodules(self, parent_modules: list[pkgutil.ModuleInfo]) -> Iterator[pkgutil.ModuleInfo]:
"""Iterate over all submodules of the given parent modules."""
specs = [info.module_finder.find_spec(info.name, None)
for info in parent_modules if info.ispkg]
search_locations = set(chain.from_iterable(
getattr(spec, 'submodule_search_locations', [])
for spec in specs if spec
))
return pkgutil.iter_modules(search_locations)
def get_path_and_prefix(self, dotted_name: str) -> tuple[str, str]:
"""
Split a dotted name into an import path and a
final prefix that is to be completed.
Examples:
'foo.bar' -> 'foo', 'bar'
'foo.' -> 'foo', ''
'.foo' -> '.', 'foo'
"""
if '.' not in dotted_name:
return '', dotted_name
if dotted_name.startswith('.'):
stripped = dotted_name.lstrip('.')
dots = '.' * (len(dotted_name) - len(stripped))
if '.' not in stripped:
return dots, stripped
path, prefix = stripped.rsplit('.', 1)
return dots + path, prefix
path, prefix = dotted_name.rsplit('.', 1)
return path, prefix
def format_completion(self, path: str, module: str) -> str:
if path == '' or path.endswith('.'):
return f'{path}{module}'
return f'{path}.{module}'
def resolve_relative_name(self, name: str, package: str) -> str | None:
"""Resolve a relative module name to an absolute name.
Example: resolve_relative_name('.foo', 'bar') -> 'bar.foo'
"""
# taken from importlib._bootstrap
level = 0
for character in name:
if character != '.':
break
level += 1
bits = package.rsplit('.', level - 1)
if len(bits) < level:
return None
base = bits[0]
name = name[level:]
return f'{base}.{name}' if name else base
@property
def global_cache(self) -> list[pkgutil.ModuleInfo]:
"""Global module cache"""
if not self._global_cache or self._curr_sys_path != sys.path:
self._curr_sys_path = sys.path[:]
# print('getting packages')
self._global_cache = list(pkgutil.iter_modules())
return self._global_cache
class ImportParser:
"""
Parses incomplete import statements that are
suitable for autocomplete suggestions.
Examples:
- import foo -> Result(from_name=None, name='foo')
- import foo. -> Result(from_name=None, name='foo.')
- from foo -> Result(from_name='foo', name=None)
- from foo import bar -> Result(from_name='foo', name='bar')
- from .foo import ( -> Result(from_name='.foo', name='')
Note that the parser works in reverse order, starting from the
last token in the input string. This makes the parser more robust
when parsing multiple statements.
"""
_ignored_tokens = {
token.INDENT, token.DEDENT, token.COMMENT,
token.NL, token.NEWLINE, token.ENDMARKER
}
_keywords = {'import', 'from', 'as'}
def __init__(self, code: str) -> None:
self.code = code
tokens = []
try:
for t in tokenize.generate_tokens(StringIO(code).readline):
if t.type not in self._ignored_tokens:
tokens.append(t)
except tokenize.TokenError as e:
if 'unexpected EOF' not in str(e):
# unexpected EOF is fine, since we're parsing an
# incomplete statement, but other errors are not
# because we may not have all the tokens so it's
# safer to bail out
tokens = []
except SyntaxError:
tokens = []
self.tokens = TokenQueue(tokens[::-1])
def parse(self) -> tuple[str | None, str | None] | None:
if not (res := self._parse()):
return None
return res.from_name, res.name
def _parse(self) -> Result | None:
with self.tokens.save_state():
return self.parse_from_import()
with self.tokens.save_state():
return self.parse_import()
def parse_import(self) -> Result:
if self.code.rstrip().endswith('import') and self.code.endswith(' '):
return Result(name='')
if self.tokens.peek_string(','):
name = ''
else:
if self.code.endswith(' '):
raise ParseError('parse_import')
name = self.parse_dotted_name()
if name.startswith('.'):
raise ParseError('parse_import')
while self.tokens.peek_string(','):
self.tokens.pop()
self.parse_dotted_as_name()
if self.tokens.peek_string('import'):
return Result(name=name)
raise ParseError('parse_import')
def parse_from_import(self) -> Result:
stripped = self.code.rstrip()
if stripped.endswith('import') and self.code.endswith(' '):
return Result(from_name=self.parse_empty_from_import(), name='')
if stripped.endswith('from') and self.code.endswith(' '):
return Result(from_name='')
if self.tokens.peek_string('(') or self.tokens.peek_string(','):
return Result(from_name=self.parse_empty_from_import(), name='')
if self.code.endswith(' '):
raise ParseError('parse_from_import')
name = self.parse_dotted_name()
if '.' in name:
self.tokens.pop_string('from')
return Result(from_name=name)
if self.tokens.peek_string('from'):
return Result(from_name=name)
from_name = self.parse_empty_from_import()
return Result(from_name=from_name, name=name)
def parse_empty_from_import(self) -> str:
if self.tokens.peek_string(','):
self.tokens.pop()
self.parse_as_names()
if self.tokens.peek_string('('):
self.tokens.pop()
self.tokens.pop_string('import')
return self.parse_from()
def parse_from(self) -> str:
from_name = self.parse_dotted_name()
self.tokens.pop_string('from')
return from_name
def parse_dotted_as_name(self) -> str:
self.tokens.pop_name()
if self.tokens.peek_string('as'):
self.tokens.pop()
with self.tokens.save_state():
return self.parse_dotted_name()
def parse_dotted_name(self) -> str:
name = []
if self.tokens.peek_string('.'):
name.append('.')
self.tokens.pop()
if (self.tokens.peek_name()
and (tok := self.tokens.peek())
and tok.string not in self._keywords):
name.append(self.tokens.pop_name())
if not name:
raise ParseError('parse_dotted_name')
while self.tokens.peek_string('.'):
name.append('.')
self.tokens.pop()
if (self.tokens.peek_name()
and (tok := self.tokens.peek())
and tok.string not in self._keywords):
name.append(self.tokens.pop_name())
else:
break
while self.tokens.peek_string('.'):
name.append('.')
self.tokens.pop()
return ''.join(name[::-1])
def parse_as_names(self) -> None:
self.parse_as_name()
while self.tokens.peek_string(','):
self.tokens.pop()
self.parse_as_name()
def parse_as_name(self) -> None:
self.tokens.pop_name()
if self.tokens.peek_string('as'):
self.tokens.pop()
self.tokens.pop_name()
class ParseError(Exception):
pass
@dataclass(frozen=True)
class Result:
from_name: str | None = None
name: str | None = None
class TokenQueue:
"""Provides helper functions for working with a sequence of tokens."""
def __init__(self, tokens: list[TokenInfo]) -> None:
self.tokens: list[TokenInfo] = tokens
self.index: int = 0
self.stack: list[int] = []
@contextmanager
def save_state(self) -> Any:
try:
self.stack.append(self.index)
yield
except ParseError:
self.index = self.stack.pop()
else:
self.stack.pop()
def __bool__(self) -> bool:
return self.index < len(self.tokens)
def peek(self) -> TokenInfo | None:
if not self:
return None
return self.tokens[self.index]
def peek_name(self) -> bool:
if not (tok := self.peek()):
return False
return tok.type == token.NAME
def pop_name(self) -> str:
tok = self.pop()
if tok.type != token.NAME:
raise ParseError('pop_name')
return tok.string
def peek_string(self, string: str) -> bool:
if not (tok := self.peek()):
return False
return tok.string == string
def pop_string(self, string: str) -> str:
tok = self.pop()
if tok.string != string:
raise ParseError('pop_string')
return tok.string
def pop(self) -> TokenInfo:
if not self:
raise ParseError('pop')
tok = self.tokens[self.index]
self.index += 1
return tok