polyloader/polyloader/_python3.py

274 lines
10 KiB
Python

import os
import sys
import marshal
import pkgutil
import types
import _imp
if sys.version_info[0:2] in [(3, 3), (3, 4)]:
from importlib._bootstrap import (cache_from_source, SourceFileLoader,
FileFinder, _verbose_message,
_get_supported_file_loaders, _relax_case,
_w_long, _code_type)
if sys.version_info[0:2] in [(3, 3)]:
from importlib._bootstrap import _MAGIC_BYTES as MAGIC_NUMBER
if sys.version_info[0:2] == (3, 4):
from importlib._bootstrap import _validate_bytecode_header, MAGIC_NUMBER
if sys.version_info[0:2] >= (3, 5):
from importlib.machinery import SourceFileLoader, FileFinder
from importlib._bootstrap import _verbose_message
from importlib._bootstrap_external import (_w_long, _code_type, cache_from_source,
_validate_bytecode_header,
MAGIC_NUMBER, _relax_case,
_get_supported_file_loaders)
SEP = os.sep
EXS = os.extsep
FLS = [('%s' + SEP + '__init__' + EXS + '%s', True),
('%s' + EXS + '%s', False)]
def _suffixer(loaders):
return [(suffix, loader)
for (loader, suffixes) in loaders
for suffix in suffixes]
class _PolySourceFileLoader(SourceFileLoader):
_compiler = None
def _poly_bytes_from_bytecode(self, fullname, data, path, st):
if hasattr(self, '_bytes_from_bytecode'):
return self._bytes_from_bytecode(fullname, data,
path, st)
self_module = sys.modules[__name__]
if hasattr(self_module, '_validate_bytecode_header'):
return _validate_bytecode_header(data, source_stats = st,
name = fullname, path = path)
raise ImportError("No bytecode handler found loading.")
# All this just to change one line.
def get_code(self, fullname):
source_path = self.get_filename(fullname)
source_mtime = None
try:
bytecode_path = cache_from_source(source_path)
except NotImplementedError:
bytecode_path = None
else:
try:
st = self.path_stats(source_path)
except NotImplementedError:
pass
else:
source_mtime = int(st['mtime'])
try:
data = self.get_data(bytecode_path)
except IOError:
pass
else:
try:
bytes_data = self._poly_bytes_from_bytecode(fullname, data,
bytecode_path,
st)
except (ImportError, EOFError):
pass
else:
_verbose_message('{} matches {}', bytecode_path,
source_path)
found = marshal.loads(bytes_data)
if isinstance(found, _code_type):
_imp._fix_co_filename(found, source_path)
_verbose_message('code object from {}',
bytecode_path)
return found
else:
msg = "Non-code object in {}"
raise ImportError(msg.format(bytecode_path),
name=fullname, path=bytecode_path)
source_bytes = self.get_data(source_path)
code_object = self._compiler(source_bytes, source_path, fullname)
_verbose_message('code object from {}', source_path)
if (not sys.dont_write_bytecode and bytecode_path is not None and
source_mtime is not None):
data = bytearray(MAGIC_NUMBER)
data.extend(_w_long(source_mtime))
data.extend(_w_long(len(source_bytes)))
data.extend(marshal.dumps(code_object))
try:
self._cache_bytecode(source_path, bytecode_path, data)
_verbose_message('wrote {!r}', bytecode_path)
except NotImplementedError:
pass
return code_object
class PolyFileFinder(FileFinder):
'''The poly version of FileFinder supports the addition of loaders
after initialization. That's pretty much the whole point of the
PolyLoader mechanism.'''
_native_loaders = []
_custom_loaders = []
def __init__(self, path):
# Base (directory) path
self.path = path or '.'
self._path_mtime = -1
self._path_cache = set()
self._relaxed_path_cache = set()
@property
def _loaders(self):
return self._custom_loaders + list(self._native_loaders)
@classmethod
def _install(cls, compiler, suffixes):
if not suffixes:
return
if isinstance(suffixes, str):
suffixes = [suffixes]
suffixset = set(suffixes)
overlap = suffixset.intersection(set([suf[0] for suf in cls._native_loaders]))
if overlap:
raise RuntimeError("Override of native Python extensions is not permitted.")
overlap = suffixset.intersection(
set([loader[0] for loader in cls._custom_loaders]))
if overlap:
# Fail silently
return
newloaderclassname = (suffixes[0].lower().capitalize() +
str(_PolySourceFileLoader).rpartition('.')[2][1:])
if isinstance(compiler, types.FunctionType):
newloader = type(newloaderclassname, (_PolySourceFileLoader,),
dict(_compiler = staticmethod(compiler)))
else:
newloader = type(newloaderclassname, (_PolySourceFileLoader,),
dict(_compiler = compiler))
cls._custom_loaders += [(EXS + suffix, newloader) for suffix in suffixset]
@classmethod
def getmodulename(cls, path):
filename = os.path.basename(path)
suffixes = ([(-len(suf[0]), suf[0]) for suf in cls._native_loaders] +
[(-len(suf[0]), suf[0]) for suf in cls._custom_loaders])
suffixes.sort()
for neglen, suffix in suffixes:
if filename[neglen:] == suffix:
return filename[:neglen]
return None
def find_loader(self, fullname):
"""Try to find a loader for the specified module, or the namespace
package portions. Returns (loader, list-of-portions)."""
is_namespace = False
tail_module = fullname.rpartition('.')[2]
try:
mtime = os.stat(self.path).st_mtime
except OSError:
mtime = -1
if mtime != self._path_mtime:
self._fill_cache()
self._path_mtime = mtime
# tail_module keeps the original casing, for __file__ and friends
if _relax_case():
cache = self._relaxed_path_cache
cache_module = tail_module.lower()
else:
cache = self._path_cache
cache_module = tail_module
# Check if the module is the name of a directory (and thus a package).
if cache_module in cache:
base_path = os.path.join(self.path, tail_module)
if os.path.isdir(base_path):
for suffix, loader in self._loaders:
init_filename = '__init__' + suffix
full_path = os.path.join(base_path, init_filename)
if os.path.isfile(full_path):
return (loader(fullname, full_path), [base_path])
else:
# A namespace package, return the path if we don't also
# find a module in the next section.
is_namespace = True
# Check for a file w/ a proper suffix exists.
for suffix, loader in self._loaders:
full_path = os.path.join(self.path, tail_module + suffix)
_verbose_message('trying {}'.format(full_path), verbosity=2)
if cache_module + suffix in cache:
if os.path.isfile(full_path):
return (loader(fullname, full_path), [])
if is_namespace:
_verbose_message('possible namespace for {}'.format(base_path))
return (None, [base_path])
return (None, [])
@classmethod
def path_hook(cls, *loader_details):
cls._native_loaders = loader_details
def path_hook_for_PolyFileFinder(path):
if not os.path.isdir(path):
raise ImportError("only directories are supported", path=path)
return PolyFileFinder(path)
return path_hook_for_PolyFileFinder
def _poly_file_finder_modules(importer, prefix=''):
if importer.path is None or not os.path.isdir(importer.path):
return
yielded = {}
try:
filenames = os.listdir(importer.path)
except OSError:
# ignore unreadable directories like import does
filenames = []
filenames.sort()
for fn in filenames:
modname = importer.getmodulename(fn)
if modname == '__init__' or modname in yielded:
continue
path = os.path.join(importer.path, fn)
ispkg = False
if not modname and os.path.isdir(path) and '.' not in fn:
modname = fn
try:
dircontents = os.listdir(path)
except OSError:
# ignore unreadable directories like import does
dircontents = []
for fn in dircontents:
subname = importer.getmodulename(fn)
if subname == '__init__':
ispkg = True
break
else:
continue # not a package
if modname and '.' not in modname:
yielded[modname] = 1
yield prefix + modname, ispkg
def install(compiler, suffixes):
filefinder = [(f, i) for i, f in enumerate(sys.path_hooks)
if repr(f).find('.path_hook_for_FileFinder') != -1]
if filefinder:
filefinder, fpos = filefinder[0]
sys.path_hooks[fpos] = PolyFileFinder.path_hook(*(_suffixer(_get_supported_file_loaders())))
sys.path_importer_cache = {}
pkgutil.iter_importer_modules.register(PolyFileFinder, _poly_file_finder_modules)
PolyFileFinder._install(compiler, suffixes)
def reset():
PolyFileFinder._custom_loaders = []