pkg/mime: layout as mini-libraries

pkg/mime/lib/src/default_extension_map.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-part of mime;
-
+library mime.extension_map;
 
 // TODO(ajohnsen): Use sorted list and binary search?
-const Map<String, String> _DEFAULT_EXTENSION_MAP = const <String, String>{
+const Map<String, String> DEFAULT_EXTENSION_MAP = const <String, String>{

[Anders Johnsen, 2014/05/13 09:16:22]

Please un-const this. Const maps are really slow for lookups.

[kevmoo, 2014/05/13 17:48:39]

Are they different than a normal LinkedHashMap?

I can't imagine that this lookup would be anywhere close to critical performance
path for any user of this library.

Perhaps we should use a HashMap instead?

[Anders Johnsen, 2014/05/14 07:36:07]

Please don't commit while there are comments.

Const-maps lookups are linear, so we compare against ~1000 strings to find a
single entry.

 '123':'application/vnd.lotus-1-2-3',
 '3dml':'text/vnd.in3d.3dml',
 '3ds':'image/x-3ds',
 '3g2':'video/3gpp2',
 '3gp':'video/3gpp',
 '7z':'application/x-7z-compressed',
 'aab':'application/x-authorware-bin',
 'aac':'audio/x-aac',
 'aam':'application/x-authorware-map',
 'aas':'application/x-authorware-seg',
@@ skipping 962 matching lines @@
 'z5':'application/x-zmachine',
 'z6':'application/x-zmachine',
 'z7':'application/x-zmachine',
 'z8':'application/x-zmachine',
 'zaz':'application/vnd.zzazz.deck+xml',
 'zip':'application/zip',
 'zir':'application/vnd.zul',
 'zirz':'application/vnd.zul',
 'zmm':'application/vnd.handheld-entertainment+xml',
 };