|
| 1 | +from contextlib import suppress |
| 2 | +from io import TextIOWrapper |
| 3 | + |
| 4 | +from . import abc |
| 5 | + |
| 6 | + |
| 7 | +class SpecLoaderAdapter: |
| 8 | + """ |
| 9 | + Adapt a package spec to adapt the underlying loader. |
| 10 | + """ |
| 11 | + |
| 12 | + def __init__(self, spec, adapter=lambda spec: spec.loader): |
| 13 | + self.spec = spec |
| 14 | + self.loader = adapter(spec) |
| 15 | + |
| 16 | + def __getattr__(self, name): |
| 17 | + return getattr(self.spec, name) |
| 18 | + |
| 19 | + |
| 20 | +class TraversableResourcesLoader: |
| 21 | + """ |
| 22 | + Adapt a loader to provide TraversableResources. |
| 23 | + """ |
| 24 | + |
| 25 | + def __init__(self, spec): |
| 26 | + self.spec = spec |
| 27 | + |
| 28 | + def get_resource_reader(self, name): |
| 29 | + return CompatibilityFiles(self.spec)._native() |
| 30 | + |
| 31 | + |
| 32 | +def _io_wrapper(file, mode='r', *args, **kwargs): |
| 33 | + if mode == 'r': |
| 34 | + return TextIOWrapper(file, *args, **kwargs) |
| 35 | + elif mode == 'rb': |
| 36 | + return file |
| 37 | + raise ValueError( |
| 38 | + "Invalid mode value '{}', only 'r' and 'rb' are supported".format(mode) |
| 39 | + ) |
| 40 | + |
| 41 | + |
| 42 | +class CompatibilityFiles: |
| 43 | + """ |
| 44 | + Adapter for an existing or non-existent resource reader |
| 45 | + to provide a compatibility .files(). |
| 46 | + """ |
| 47 | + |
| 48 | + class SpecPath(abc.Traversable): |
| 49 | + """ |
| 50 | + Path tied to a module spec. |
| 51 | + Can be read and exposes the resource reader children. |
| 52 | + """ |
| 53 | + |
| 54 | + def __init__(self, spec, reader): |
| 55 | + self._spec = spec |
| 56 | + self._reader = reader |
| 57 | + |
| 58 | + def iterdir(self): |
| 59 | + if not self._reader: |
| 60 | + return iter(()) |
| 61 | + return iter( |
| 62 | + CompatibilityFiles.ChildPath(self._reader, path) |
| 63 | + for path in self._reader.contents() |
| 64 | + ) |
| 65 | + |
| 66 | + def is_file(self): |
| 67 | + return False |
| 68 | + |
| 69 | + is_dir = is_file |
| 70 | + |
| 71 | + def joinpath(self, other): |
| 72 | + if not self._reader: |
| 73 | + return CompatibilityFiles.OrphanPath(other) |
| 74 | + return CompatibilityFiles.ChildPath(self._reader, other) |
| 75 | + |
| 76 | + @property |
| 77 | + def name(self): |
| 78 | + return self._spec.name |
| 79 | + |
| 80 | + def open(self, mode='r', *args, **kwargs): |
| 81 | + return _io_wrapper(self._reader.open_resource(None), mode, *args, **kwargs) |
| 82 | + |
| 83 | + class ChildPath(abc.Traversable): |
| 84 | + """ |
| 85 | + Path tied to a resource reader child. |
| 86 | + Can be read but doesn't expose any meaningful children. |
| 87 | + """ |
| 88 | + |
| 89 | + def __init__(self, reader, name): |
| 90 | + self._reader = reader |
| 91 | + self._name = name |
| 92 | + |
| 93 | + def iterdir(self): |
| 94 | + return iter(()) |
| 95 | + |
| 96 | + def is_file(self): |
| 97 | + return self._reader.is_resource(self.name) |
| 98 | + |
| 99 | + def is_dir(self): |
| 100 | + return not self.is_file() |
| 101 | + |
| 102 | + def joinpath(self, other): |
| 103 | + return CompatibilityFiles.OrphanPath(self.name, other) |
| 104 | + |
| 105 | + @property |
| 106 | + def name(self): |
| 107 | + return self._name |
| 108 | + |
| 109 | + def open(self, mode='r', *args, **kwargs): |
| 110 | + return _io_wrapper( |
| 111 | + self._reader.open_resource(self.name), mode, *args, **kwargs |
| 112 | + ) |
| 113 | + |
| 114 | + class OrphanPath(abc.Traversable): |
| 115 | + """ |
| 116 | + Orphan path, not tied to a module spec or resource reader. |
| 117 | + Can't be read and doesn't expose any meaningful children. |
| 118 | + """ |
| 119 | + |
| 120 | + def __init__(self, *path_parts): |
| 121 | + if len(path_parts) < 1: |
| 122 | + raise ValueError('Need at least one path part to construct a path') |
| 123 | + self._path = path_parts |
| 124 | + |
| 125 | + def iterdir(self): |
| 126 | + return iter(()) |
| 127 | + |
| 128 | + def is_file(self): |
| 129 | + return False |
| 130 | + |
| 131 | + is_dir = is_file |
| 132 | + |
| 133 | + def joinpath(self, other): |
| 134 | + return CompatibilityFiles.OrphanPath(*self._path, other) |
| 135 | + |
| 136 | + @property |
| 137 | + def name(self): |
| 138 | + return self._path[-1] |
| 139 | + |
| 140 | + def open(self, mode='r', *args, **kwargs): |
| 141 | + raise FileNotFoundError("Can't open orphan path") |
| 142 | + |
| 143 | + def __init__(self, spec): |
| 144 | + self.spec = spec |
| 145 | + |
| 146 | + @property |
| 147 | + def _reader(self): |
| 148 | + with suppress(AttributeError): |
| 149 | + return self.spec.loader.get_resource_reader(self.spec.name) |
| 150 | + |
| 151 | + def _native(self): |
| 152 | + """ |
| 153 | + Return the native reader if it supports files(). |
| 154 | + """ |
| 155 | + reader = self._reader |
| 156 | + return reader if hasattr(reader, 'files') else self |
| 157 | + |
| 158 | + def __getattr__(self, attr): |
| 159 | + return getattr(self._reader, attr) |
| 160 | + |
| 161 | + def files(self): |
| 162 | + return CompatibilityFiles.SpecPath(self.spec, self._reader) |
| 163 | + |
| 164 | + |
| 165 | +def wrap_spec(package): |
| 166 | + """ |
| 167 | + Construct a package spec with traversable compatibility |
| 168 | + on the spec/loader/reader. |
| 169 | + """ |
| 170 | + return SpecLoaderAdapter(package.__spec__, TraversableResourcesLoader) |
0 commit comments