gistfile1.txt

diff --git a/mutagen/_util.py b/mutagen/_util.py
index 1332f9d..795eec4 100644
--- a/mutagen/_util.py
+++ b/mutagen/_util.py
@@ -19,13 +19,6 @@ import errno
 import decimal
 from io import BytesIO
 
-try:
-    import mmap
-except ImportError:
-    # Google App Engine has no mmap:
-    #   https://github.com/quodlibet/mutagen/issues/286
-    mmap = None
-
 from collections import namedtuple
 from contextlib import contextmanager
 from functools import wraps
@@ -683,64 +676,6 @@ def seek_end(fileobj, offset):
         fileobj.seek(-offset, 2)
 
 
-def mmap_move(fileobj, dest, src, count):
-    """Mmaps the file object if possible and moves 'count' data
-    from 'src' to 'dest'. All data has to be inside the file size
-    (enlarging the file through this function isn't possible)
-
-    Will adjust the file offset.
-
-    Args:
-        fileobj (fileobj)
-        dest (int): The destination offset
-        src (int): The source offset
-        count (int) The amount of data to move
-    Raises:
-        mmap.error: In case move failed
-        IOError: In case an operation on the fileobj fails
-        ValueError: In case invalid parameters were given
-    """
-
-    assert mmap is not None, "no mmap support"
-
-    if dest < 0 or src < 0 or count < 0:
-        raise ValueError("Invalid parameters")
-
-    try:
-        fileno = fileobj.fileno()
-    except (AttributeError, IOError):
-        raise mmap.error(
-            "File object does not expose/support a file descriptor")
-
-    fileobj.seek(0, 2)
-    filesize = fileobj.tell()
-    length = max(dest, src) + count
-
-    if length > filesize:
-        raise ValueError("Not in file size boundary")
-
-    offset = ((min(dest, src) // mmap.ALLOCATIONGRANULARITY) *
-              mmap.ALLOCATIONGRANULARITY)
-    assert dest >= offset
-    assert src >= offset
-    assert offset % mmap.ALLOCATIONGRANULARITY == 0
-
-    # Windows doesn't handle empty mappings, add a fast path here instead
-    if count == 0:
-        return
-
-    # fast path
-    if src == dest:
-        return
-
-    fileobj.flush()
-    file_map = mmap.mmap(fileno, length - offset, offset=offset)
-    try:
-        file_map.move(dest - offset, src - offset, count)
-    finally:
-        file_map.close()
-
-
 def resize_file(fobj, diff, BUFFER_SIZE=2 ** 16):
     """Resize a file by `diff`.
 
@@ -825,8 +760,7 @@ def insert_bytes(fobj, size, offset, BUFFER_SIZE=2 ** 16):
     """Insert size bytes of empty space starting at offset.
 
     fobj must be an open file object, open rb+ or
-    equivalent. Mutagen tries to use mmap to resize the file, but
-    falls back to a significantly slower method if mmap fails.
+    equivalent.
 
     Args:
         fobj (fileobj)
@@ -848,21 +782,14 @@ def insert_bytes(fobj, size, offset, BUFFER_SIZE=2 ** 16):
 
     resize_file(fobj, size, BUFFER_SIZE)
 
-    if mmap is not None:
-        try:
-            mmap_move(fobj, offset + size, offset, movesize)
-        except mmap.error:
-            fallback_move(fobj, offset + size, offset, movesize, BUFFER_SIZE)
-    else:
-        fallback_move(fobj, offset + size, offset, movesize, BUFFER_SIZE)
+    fallback_move(fobj, offset + size, offset, movesize, BUFFER_SIZE)
 
 
 def delete_bytes(fobj, size, offset, BUFFER_SIZE=2 ** 16):
     """Delete size bytes of empty space starting at offset.
 
     fobj must be an open file object, open rb+ or
-    equivalent. Mutagen tries to use mmap to resize the file, but
-    falls back to a significantly slower method if mmap fails.
+    equivalent.
 
     Args:
         fobj (fileobj)
@@ -882,13 +809,7 @@ def delete_bytes(fobj, size, offset, BUFFER_SIZE=2 ** 16):
     if movesize < 0:
         raise ValueError
 
-    if mmap is not None:
-        try:
-            mmap_move(fobj, offset, offset + size, movesize)
-        except mmap.error:
-            fallback_move(fobj, offset, offset + size, movesize, BUFFER_SIZE)
-    else:
-        fallback_move(fobj, offset, offset + size, movesize, BUFFER_SIZE)
+    fallback_move(fobj, offset, offset + size, movesize, BUFFER_SIZE)
 
     resize_file(fobj, -size, BUFFER_SIZE)
 
diff --git a/tests/test__util.py b/tests/test__util.py
index 0ed25ed..0a079dd 100644
--- a/tests/test__util.py
+++ b/tests/test__util.py
@@ -2,7 +2,7 @@
 
 from mutagen._util import DictMixin, cdata, insert_bytes, delete_bytes, \
     decode_terminated, dict_match, enum, get_size, BitReader, BitReaderError, \
-    resize_bytes, seek_end, mmap_move, verify_fileobj, fileobj_name, \
+    resize_bytes, seek_end, verify_fileobj, fileobj_name, \
     read_full, flags, resize_file, fallback_move, encode_endian, loadfile, \
     intround, verify_filename
 from mutagen._compat import text_type, itervalues, iterkeys, iteritems, PY2, \
@@ -11,7 +11,6 @@ from tests import TestCase, get_temp_empty
 import os
 import random
 import tempfile
-import mmap
 import errno
 
 try:
@@ -376,32 +375,12 @@ class TMoveMixin(object):
             self.MOVE(o, 0, 1, 2)
             self.MOVE(o, 1, 0, 2)
 
-    def test_larger_than_page_size(self):
-        off = mmap.ALLOCATIONGRANULARITY
-        with self.file(b"f" * off * 2) as o:
-            self.MOVE(o, off, off + 1, off - 1)
-            self.MOVE(o, off + 1, off, off - 1)
-
-        with self.file(b"f" * off * 2 + b"x") as o:
-            self.MOVE(o, off * 2 - 1, off * 2, 1)
-            self.assertEqual(self.read(o)[-3:], b"fxx")
-
 
 class Tfallback_move(TestCase, TMoveMixin):
 
     MOVE = staticmethod(fallback_move)
 
 
-class MmapMove(TestCase, TMoveMixin):
-
-    MOVE = staticmethod(mmap_move)
-
-    def test_stringio(self):
-        self.assertRaises(mmap.error, mmap_move, cBytesIO(), 0, 0, 0)
-
-    def test_no_fileno(self):
-        self.assertRaises(mmap.error, mmap_move, object(), 0, 0, 0)
-
 
 class FileHandling(TestCase):
     def file(self, contents):
@@ -588,41 +567,6 @@ class FileHandling(TestCase):
                 self.failUnless(fobj.read() == data)
 
 
-class FileHandlingMockedMMap(FileHandling):
-
-    def setUp(self):
-        def MockMMap2(*args, **kwargs):
-            raise mmap.error
-
-        self._orig_mmap = mmap.mmap
-        mmap.mmap = MockMMap2
-
-    def tearDown(self):
-        mmap.mmap = self._orig_mmap
-
-
-class FileHandlingNoMMap(FileHandling):
-    """Disables mmap and makes sure it raises if it still gets used somehow"""
-
-    def setUp(self):
-        from mutagen import _util
-
-        def MockMMap2(*args, **kwargs):
-            assert False
-
-        self._orig_mmap = mmap.mmap
-        mmap.mmap = MockMMap2
-
-        _util.mmap = None
-
-    def tearDown(self):
-        from mutagen import _util
-        import mmap
-
-        _util.mmap = mmap
-        mmap.mmap = self._orig_mmap
-
-
 class Tdict_match(TestCase):
 
     def test_match(self):