Added context manager, __del__ and close methods

Tests/test_file_tar.py

@@ -15,21 +15,25 @@ class TestFileTar(PillowTestCase):
             self.skipTest("neither jpeg nor zip support available")
 
     def test_sanity(self):
-        if "zip_decoder" in codecs:
-            tar = TarIO.TarIO(TEST_TAR_FILE, 'hopper.png')
-            im = Image.open(tar)
-            im.load()
-            self.assertEqual(im.mode, "RGB")
-            self.assertEqual(im.size, (128, 128))
-            self.assertEqual(im.format, "PNG")
+        for codec, test_path, format in [
+            ['zip_decoder', 'hopper.png', 'PNG'],
+            ['jpeg_decoder', 'hopper.jpg', 'JPEG']
+        ]:
+            if codec in codecs:
+                tar = TarIO.TarIO(TEST_TAR_FILE, test_path)
+                im = Image.open(tar)
+                im.load()
+                self.assertEqual(im.mode, "RGB")
+                self.assertEqual(im.size, (128, 128))
+                self.assertEqual(im.format, format)
 
-        if "jpeg_decoder" in codecs:
-            tar = TarIO.TarIO(TEST_TAR_FILE, 'hopper.jpg')
-            im = Image.open(tar)
-            im.load()
-            self.assertEqual(im.mode, "RGB")
-            self.assertEqual(im.size, (128, 128))
-            self.assertEqual(im.format, "JPEG")
+    def test_close(self):
+        tar = TarIO.TarIO(TEST_TAR_FILE, 'hopper.jpg')
+        tar.close()
+
+    def test_contextmanager(self):
+        with TarIO.TarIO(TEST_TAR_FILE, 'hopper.jpg') as tar:
+            pass
 
 
 if __name__ == '__main__':

src/PIL/TarIO.py

@@ -14,6 +14,7 @@
 # See the README file for information on usage and redistribution.
 #
 
+import sys
 from . import ContainerIO
 
 
@@ -30,11 +31,11 @@ class TarIO(ContainerIO.ContainerIO):
         :param tarfile: Name of TAR file.
         :param file: Name of member file.
         """
-        fh = open(tarfile, "rb")
+        self.fh = open(tarfile, "rb")
 
         while True:
 
-            s = fh.read(512)
+            s = self.fh.read(512)
             if len(s) != 512:
                 raise IOError("unexpected end of tar file")
 
@@ -50,7 +51,21 @@ class TarIO(ContainerIO.ContainerIO):
             if file == name:
                 break
 
-            fh.seek((size + 511) & (~511), 1)
+            self.fh.seek((size + 511) & (~511), 1)
 
         # Open region
-        ContainerIO.ContainerIO.__init__(self, fh, fh.tell(), size)
+        ContainerIO.ContainerIO.__init__(self, self.fh, self.fh.tell(), size)
+
+    # Context Manager Support
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        self.close()
+
+    if sys.version_info.major >= 3:
+        def __del__(self):
+            self.close()
+
+    def close(self):
+        self.fh.close()