Add Formats.list_extensions

CHANGES.md

@@ -1,5 +1,6 @@
 v3.0.6 (dev)
 ------------
+* Added 'list_extensions' method to xphyle.formats.Formats
 
 v3.0.5 (2017.07.19)
 -------------------

tests/test_formats.py

@@ -64,6 +64,13 @@ def test_list_formats(self):
             set(('gzip','gz','pigz')),
             set(get_format('gzip').aliases))
 
+    def test_list_extensions(self):
+        self.assertSetEqual(
+            set((
+                '.gz', '.bgz', '.bz2', '.bzip', '.bzip2', '.xz', '.lzma', 
+                '.7z', '.7zip')),
+            set(FORMATS.list_extensions(True)))
+
     def test_guess_format(self):
         self.assertEqual('gzip', FORMATS.guess_compression_format('gz'))
         self.assertEqual('gzip', FORMATS.guess_compression_format('.gz'))

xphyle/formats.py

@@ -15,8 +15,8 @@
 from xphyle.progress import PROCESS_PROGRESS, iter_file_chunked
 from xphyle.types import (
     FileMode, ModeCoding, ModeArg, PathOrFile, FileLike, Union, Callable,
-    Iterable, Iterator, List, Tuple, ModuleType, PathLike, FileLikeInterface,
-    FileLikeBase, AnyStr, AnyChar, IO, cast)
+    Iterable, Iterator, List, Tuple, Set, ModuleType, PathLike, 
+    FileLikeInterface, FileLikeBase, AnyStr, AnyChar, IO, cast)
 
 class ThreadsVar(object):
     """Maintain ``threads`` variable.
@@ -1117,6 +1117,19 @@ def list_compression_formats(self) -> Tuple:
         """
         return tuple(self.compression_formats.keys())
 
+    def list_extensions(self, with_sep: bool = False) -> Iterable[str]:
+        """Returns an iterable with all valid extensions.
+        
+        Args:
+            with_sep: Add separator prefix to each extension.
+        """
+        exts = set() # type: Set[str]
+        for fmt in self.compression_formats.values():
+            exts.update(fmt.exts)
+        if with_sep:
+            exts = set("{}{}".format(os.extsep, ext) for ext in exts)
+        return exts
+
     def get_compression_format(self, name: str) -> CompressionFormat:
         """Returns the CompressionFormat associated with the given name.