cpython/Lib/importlib/abc.py

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"""Abstract base classes related to import."""
from . import _bootstrap
from . import machinery
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
from . import util
import abc
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
import imp
import io
import marshal
import os.path
import sys
import tokenize
import types
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
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import warnings
class Loader(metaclass=abc.ABCMeta):
"""Abstract base class for import loaders."""
@abc.abstractmethod
def load_module(self, fullname:str) -> types.ModuleType:
"""Abstract method which when implemented should load a module."""
raise NotImplementedError
class Finder(metaclass=abc.ABCMeta):
"""Abstract base class for import finders."""
@abc.abstractmethod
def find_module(self, fullname:str, path:[str]=None) -> Loader:
"""Abstract method which when implemented should find a module."""
raise NotImplementedError
Finder.register(machinery.BuiltinImporter)
Finder.register(machinery.FrozenImporter)
Finder.register(machinery.PathFinder)
class ResourceLoader(Loader):
"""Abstract base class for loaders which can return data from their
back-end storage.
This ABC represents one of the optional protocols specified by PEP 302.
"""
@abc.abstractmethod
def get_data(self, path:str) -> bytes:
"""Abstract method which when implemented should return the bytes for
the specified path."""
raise NotImplementedError
class InspectLoader(Loader):
"""Abstract base class for loaders which support inspection about the
modules they can load.
This ABC represents one of the optional protocols specified by PEP 302.
"""
@abc.abstractmethod
def is_package(self, fullname:str) -> bool:
"""Abstract method which when implemented should return whether the
module is a package."""
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
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raise NotImplementedError
@abc.abstractmethod
def get_code(self, fullname:str) -> types.CodeType:
"""Abstract method which when implemented should return the code object
for the module"""
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
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raise NotImplementedError
@abc.abstractmethod
def get_source(self, fullname:str) -> str:
"""Abstract method which should return the source code for the
module."""
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
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raise NotImplementedError
InspectLoader.register(machinery.BuiltinImporter)
InspectLoader.register(machinery.FrozenImporter)
class ExecutionLoader(InspectLoader):
"""Abstract base class for loaders that wish to support the execution of
modules as scripts.
This ABC represents one of the optional protocols specified in PEP 302.
"""
@abc.abstractmethod
def get_filename(self, fullname:str) -> str:
"""Abstract method which should return the value that __file__ is to be
set to."""
raise NotImplementedError
class SourceLoader(_bootstrap.SourceLoader, ResourceLoader, ExecutionLoader):
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
"""Abstract base class for loading source code (and optionally any
corresponding bytecode).
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
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To support loading from source code, the abstractmethods inherited from
ResourceLoader and ExecutionLoader need to be implemented. To also support
loading from bytecode, the optional methods specified directly by this ABC
is required.
Inherited abstractmethods not implemented in this ABC:
* ResourceLoader.get_data
* ExecutionLoader.get_filename
"""
def path_mtime(self, path:str) -> int:
"""Return the modification time for the path."""
raise NotImplementedError
def set_data(self, path:str, data:bytes) -> None:
"""Write the bytes to the path (if possible).
Any needed intermediary directories are to be created. If for some
reason the file cannot be written because of permissions, fail
silently.
"""
raise NotImplementedError
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
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class PyLoader(SourceLoader):
"""Implement the deprecated PyLoader ABC in terms of SourceLoader.
This class has been deprecated! It is slated for removal in Python 3.4.
If compatibility with Python 3.1 is not needed then implement the
SourceLoader ABC instead of this class. If Python 3.1 compatibility is
needed, then use the following idiom to have a single class that is
compatible with Python 3.1 onwards::
try:
from importlib.abc import SourceLoader
except ImportError:
from importlib.abc import PyLoader as SourceLoader
class CustomLoader(SourceLoader):
def get_filename(self, fullname):
# Implement ...
def source_path(self, fullname):
'''Implement source_path in terms of get_filename.'''
try:
return self.get_filename(fullname)
except ImportError:
return None
def is_package(self, fullname):
filename = os.path.basename(self.get_filename(fullname))
return os.path.splitext(filename)[0] == '__init__'
"""
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
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@abc.abstractmethod
def is_package(self, fullname):
raise NotImplementedError
@abc.abstractmethod
def source_path(self, fullname:str) -> object:
"""Abstract method which when implemented should return the path to the
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
source code for the module."""
raise NotImplementedError
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
def get_filename(self, fullname):
"""Implement get_filename in terms of source_path.
As get_filename should only return a source file path there is no
chance of the path not existing but loading still being possible, so
ImportError should propagate instead of being turned into returning
None.
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
"""
warnings.warn("importlib.abc.PyLoader is deprecated and is "
"slated for removal in Python 3.4; "
"use SourceLoader instead. "
"See the importlib documentation on how to be "
"compatible with Python 3.1 onwards.",
PendingDeprecationWarning)
path = self.source_path(fullname)
if path is None:
raise ImportError
else:
return path
class PyPycLoader(PyLoader):
"""Abstract base class to assist in loading source and bytecode by
requiring only back-end storage methods to be implemented.
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
This class has been deprecated! Removal is slated for Python 3.4. Implement
the SourceLoader ABC instead. If Python 3.1 compatibility is needed, see
PyLoader.
The methods get_code, get_source, and load_module are implemented for the
user.
"""
Implement importlib.abc.SourceLoader and deprecate PyLoader and PyPycLoader. SourceLoader is a simplification of both PyLoader and PyPycLoader. If one only wants to use source, then they need to only implement get_data and get_filename. To also use bytecode -- sourceless loading is not supported -- then two abstract methods -- path_mtime and set_data -- need to be implemented. Compared to PyLoader and PyPycLoader, there are less abstract methods introduced and bytecode files become an optimization controlled by the ABC and hidden from the user (this need came about as PEP 3147 showed that not treating bytecode as an optimization can cause problems for compatibility). PyLoader is deprecated in favor of SourceLoader. To be compatible from Python 3.1 onwards, a subclass need only use simple methods for source_path and is_package. Otherwise conditional subclassing based on whether Python 3.1 or Python 3.2 is being is the only change. The documentation and docstring for PyLoader explain what is exactly needed. PyPycLoader is deprecated also in favor of SourceLoader. Because PEP 3147 shifted bytecode path details so much, there is no foolproof way to provide backwards-compatibility with SourceLoader. Because of this the class is simply deprecated and users should move to SourceLoader (and optionally PyLoader for Python 3.1). This does lead to a loss of support for sourceless loading unfortunately. At some point before Python 3.2 is released, SourceLoader will be moved over to importlib._bootstrap so that the core code of importlib relies on the new code instead of the old PyPycLoader code. This commit is being done now so that there is no issue in having the API in Python 3.1a1.
2010-06-27 20:57:46 -03:00
def get_filename(self, fullname):
"""Return the source or bytecode file path."""
path = self.source_path(fullname)
if path is not None:
return path
path = self.bytecode_path(fullname)
if path is not None:
return path
raise ImportError("no source or bytecode path available for "
"{0!r}".format(fullname))
def get_code(self, fullname):
"""Get a code object from source or bytecode."""
warnings.warn("importlib.abc.PyPycLoader is deprecated and slated for "
"removal in Python 3.4; use SourceLoader instead. "
"If Python 3.1 compatibility is required, see the "
"latest documentation for PyLoader.",
PendingDeprecationWarning)
source_timestamp = self.source_mtime(fullname)
# Try to use bytecode if it is available.
bytecode_path = self.bytecode_path(fullname)
if bytecode_path:
data = self.get_data(bytecode_path)
try:
magic = data[:4]
if len(magic) < 4:
raise ImportError("bad magic number in {}".format(fullname))
raw_timestamp = data[4:8]
if len(raw_timestamp) < 4:
raise EOFError("bad timestamp in {}".format(fullname))
pyc_timestamp = marshal._r_long(raw_timestamp)
bytecode = data[8:]
# Verify that the magic number is valid.
if imp.get_magic() != magic:
raise ImportError("bad magic number in {}".format(fullname))
# Verify that the bytecode is not stale (only matters when
# there is source to fall back on.
if source_timestamp:
if pyc_timestamp < source_timestamp:
raise ImportError("bytecode is stale")
except (ImportError, EOFError):
# If source is available give it a shot.
if source_timestamp is not None:
pass
else:
raise
else:
# Bytecode seems fine, so try to use it.
return marshal.loads(bytecode)
elif source_timestamp is None:
raise ImportError("no source or bytecode available to create code "
"object for {0!r}".format(fullname))
# Use the source.
source_path = self.source_path(fullname)
if source_path is None:
message = "a source path must exist to load {0}".format(fullname)
raise ImportError(message)
source = self.get_data(source_path)
code_object = compile(source, source_path, 'exec', dont_inherit=True)
# Generate bytecode and write it out.
if not sys.dont_write_bytecode:
data = bytearray(imp.get_magic())
data.extend(marshal._w_long(source_timestamp))
data.extend(marshal.dumps(code_object))
self.write_bytecode(fullname, data)
return code_object
@abc.abstractmethod
def source_mtime(self, fullname:str) -> int:
"""Abstract method which when implemented should return the
modification time for the source of the module."""
raise NotImplementedError
@abc.abstractmethod
def bytecode_path(self, fullname:str) -> object:
"""Abstract method which when implemented should return the path to the
bytecode for the module."""
raise NotImplementedError
@abc.abstractmethod
def write_bytecode(self, fullname:str, bytecode:bytes) -> bool:
"""Abstract method which when implemented should attempt to write the
bytecode for the module, returning a boolean representing whether the
bytecode was written or not."""
raise NotImplementedError