distlib.resources

distlib.resources

Source code for distlib.resources

# -*- coding: utf-8 -*-
#
# Copyright (C) 2013-2017 Vinay Sajip.
# Licensed to the Python Software Foundation under a contributor agreement.
# See LICENSE.txt and CONTRIBUTORS.txt.
#
from __future__ import unicode_literals

import bisect
import io
import logging
import os
import pkgutil
import sys
import types
import zipimport

from . import DistlibException
from .util import cached_property, get_cache_base, Cache

logger = logging.getLogger(__name__)


cache = None    # created when needed


[docs]class ResourceCache(Cache):
[docs] def __init__(self, base=None): if base is None: # Use native string to avoid issues on 2.x: see Python #20140. base = os.path.join(get_cache_base(), str('resource-cache')) super(ResourceCache, self).__init__(base)
[docs] def is_stale(self, resource, path): """ Is the cache stale for the given resource? :param resource: The :class:`Resource` being cached. :param path: The path of the resource in the cache. :return: True if the cache is stale. """ # Cache invalidation is a hard problem :-) return True
[docs] def get(self, resource): """ Get a resource into the cache, :param resource: A :class:`Resource` instance. :return: The pathname of the resource in the cache. """ prefix, path = resource.finder.get_cache_info(resource) if prefix is None: result = path else: result = os.path.join(self.base, self.prefix_to_dir(prefix), path) dirname = os.path.dirname(result) if not os.path.isdir(dirname): os.makedirs(dirname) if not os.path.exists(result): stale = True else: stale = self.is_stale(resource, path) if stale: # write the bytes of the resource to the cache location with open(result, 'wb') as f: f.write(resource.bytes) return result
class ResourceBase(object): def __init__(self, finder, name): self.finder = finder self.name = name
[docs]class Resource(ResourceBase): """ A class representing an in-package resource, such as a data file. This is not normally instantiated by user code, but rather by a :class:`ResourceFinder` which manages the resource. """ is_container = False # Backwards compatibility
[docs] def as_stream(self): """ Get the resource as a stream. This is not a property to make it obvious that it returns a new stream each time. """ return self.finder.get_stream(self)
@cached_property def file_path(self): global cache if cache is None: cache = ResourceCache() return cache.get(self) @cached_property def bytes(self): return self.finder.get_bytes(self) @cached_property def size(self): return self.finder.get_size(self)
class ResourceContainer(ResourceBase): is_container = True # Backwards compatibility @cached_property def resources(self): return self.finder.get_resources(self)
[docs]class ResourceFinder(object): """ Resource finder for file system resources. """ if sys.platform.startswith('java'): skipped_extensions = ('.pyc', '.pyo', '.class') else: skipped_extensions = ('.pyc', '.pyo')
[docs] def __init__(self, module): self.module = module self.loader = getattr(module, '__loader__', None) self.base = os.path.dirname(getattr(module, '__file__', ''))
def _adjust_path(self, path): return os.path.realpath(path) def _make_path(self, resource_name): # Issue #50: need to preserve type of path on Python 2.x # like os.path._get_sep if isinstance(resource_name, bytes): # should only happen on 2.x sep = b'/' else: sep = '/' parts = resource_name.split(sep) parts.insert(0, self.base) result = os.path.join(*parts) return self._adjust_path(result) def _find(self, path): return os.path.exists(path) def get_cache_info(self, resource): return None, resource.path
[docs] def find(self, resource_name): path = self._make_path(resource_name) if not self._find(path): result = None else: if self._is_directory(path): result = ResourceContainer(self, resource_name) else: result = Resource(self, resource_name) result.path = path return result
[docs] def get_stream(self, resource): return open(resource.path, 'rb')
[docs] def get_bytes(self, resource): with open(resource.path, 'rb') as f: return f.read()
[docs] def get_size(self, resource): return os.path.getsize(resource.path)
def get_resources(self, resource): def allowed(f): return (f != '__pycache__' and not f.endswith(self.skipped_extensions)) return set([f for f in os.listdir(resource.path) if allowed(f)])
[docs] def is_container(self, resource): return self._is_directory(resource.path)
_is_directory = staticmethod(os.path.isdir)
[docs] def iterator(self, resource_name): resource = self.find(resource_name) if resource is not None: todo = [resource] while todo: resource = todo.pop(0) yield resource if resource.is_container: rname = resource.name for name in resource.resources: if not rname: new_name = name else: new_name = '/'.join([rname, name]) child = self.find(new_name) if child.is_container: todo.append(child) else: yield child
[docs]class ZipResourceFinder(ResourceFinder): """ Resource finder for resources in .zip files. """ def __init__(self, module): super(ZipResourceFinder, self).__init__(module) archive = self.loader.archive self.prefix_len = 1 + len(archive) # PyPy doesn't have a _files attr on zipimporter, and you can't set one if hasattr(self.loader, '_files'): self._files = self.loader._files else: self._files = zipimport._zip_directory_cache[archive] self.index = sorted(self._files) def _adjust_path(self, path): return path def _find(self, path): path = path[self.prefix_len:] if path in self._files: result = True else: if path and path[-1] != os.sep: path = path + os.sep i = bisect.bisect(self.index, path) try: result = self.index[i].startswith(path) except IndexError: result = False if not result: logger.debug('_find failed: %r %r', path, self.loader.prefix) else: logger.debug('_find worked: %r %r', path, self.loader.prefix) return result def get_cache_info(self, resource): prefix = self.loader.archive path = resource.path[1 + len(prefix):] return prefix, path def get_bytes(self, resource): return self.loader.get_data(resource.path) def get_stream(self, resource): return io.BytesIO(self.get_bytes(resource)) def get_size(self, resource): path = resource.path[self.prefix_len:] return self._files[path][3] def get_resources(self, resource): path = resource.path[self.prefix_len:] if path and path[-1] != os.sep: path += os.sep plen = len(path) result = set() i = bisect.bisect(self.index, path) while i < len(self.index): if not self.index[i].startswith(path): break s = self.index[i][plen:] result.add(s.split(os.sep, 1)[0]) # only immediate children i += 1 return result def _is_directory(self, path): path = path[self.prefix_len:] if path and path[-1] != os.sep: path += os.sep i = bisect.bisect(self.index, path) try: result = self.index[i].startswith(path) except IndexError: result = False return result
_finder_registry = { type(None): ResourceFinder, zipimport.zipimporter: ZipResourceFinder } try: # In Python 3.6, _frozen_importlib -> _frozen_importlib_external try: import _frozen_importlib_external as _fi except ImportError: import _frozen_importlib as _fi _finder_registry[_fi.SourceFileLoader] = ResourceFinder _finder_registry[_fi.FileFinder] = ResourceFinder # See issue #146 _finder_registry[_fi.SourcelessFileLoader] = ResourceFinder del _fi except (ImportError, AttributeError): pass
[docs]def register_finder(loader, finder_maker): _finder_registry[type(loader)] = finder_maker
_finder_cache = {}
[docs]def finder(package): """ Return a resource finder for a package. :param package: The name of the package. :return: A :class:`ResourceFinder` instance for the package. """ if package in _finder_cache: result = _finder_cache[package] else: if package not in sys.modules: __import__(package) module = sys.modules[package] path = getattr(module, '__path__', None) if path is None: raise DistlibException('You cannot get a finder for a module, ' 'only for a package') loader = getattr(module, '__loader__', None) finder_maker = _finder_registry.get(type(loader)) if finder_maker is None: raise DistlibException('Unable to locate finder for %r' % package) result = finder_maker(module) _finder_cache[package] = result return result
_dummy_module = types.ModuleType(str('__dummy__')) def finder_for_path(path): """ Return a resource finder for a path, which should represent a container. :param path: The path. :return: A :class:`ResourceFinder` instance for the path. """ result = None # calls any path hooks, gets importer into cache pkgutil.get_importer(path) loader = sys.path_importer_cache.get(path) finder = _finder_registry.get(type(loader)) if finder: module = _dummy_module module.__file__ = os.path.join(path, '') module.__loader__ = loader result = finder(module) return result