MimeTypeMap.java revision 0f11696164e1dadd2d33dddeca418f719f26bc10 
1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.webkit;
18
19import android.text.TextUtils;
20import java.util.HashMap;
21import java.util.regex.Pattern;
22import libcore.net.MimeUtils;
23
24/**
25 * Two-way map that maps MIME-types to file extensions and vice versa.
26 *
27 * <p>See also {@link java.net.URLConnection#guessContentTypeFromName}
28 * and {@link java.net.URLConnection#guessContentTypeFromStream}. This
29 * class and {@code URLConnection} share the same MIME-type database.
30 */
31public class MimeTypeMap {
32    private static final MimeTypeMap sMimeTypeMap = new MimeTypeMap();
33
34    private MimeTypeMap() {
35    }
36
37    /**
38     * Returns the file extension or an empty string iff there is no
39     * extension. This method is a convenience method for obtaining the
40     * extension of a url and has undefined results for other Strings.
41     * @param url
42     * @return The file extension of the given url.
43     */
44    public static String getFileExtensionFromUrl(String url) {
45        if (!TextUtils.isEmpty(url)) {
46            int query = url.lastIndexOf('?');
47            if (query > 0) {
48                url = url.substring(0, query);
49            }
50            int filenamePos = url.lastIndexOf('/');
51            String filename =
52                0 <= filenamePos ? url.substring(filenamePos + 1) : url;
53
54            // if the filename contains special characters, we don't
55            // consider it valid for our matching purposes:
56            if (!filename.isEmpty() &&
57                Pattern.matches("[a-zA-Z_0-9\\.\\-\\(\\)\\%]+", filename)) {
58                int dotPos = filename.lastIndexOf('.');
59                if (0 <= dotPos) {
60                    return filename.substring(dotPos + 1);
61                }
62            }
63        }
64
65        return "";
66    }
67
68    /**
69     * Return true if the given MIME type has an entry in the map.
70     * @param mimeType A MIME type (i.e. text/plain)
71     * @return True iff there is a mimeType entry in the map.
72     */
73    public boolean hasMimeType(String mimeType) {
74        return MimeUtils.hasMimeType(mimeType);
75    }
76
77    /**
78     * Return the MIME type for the given extension.
79     * @param extension A file extension without the leading '.'
80     * @return The MIME type for the given extension or null iff there is none.
81     */
82    public String getMimeTypeFromExtension(String extension) {
83        return MimeUtils.guessMimeTypeFromExtension(extension);
84    }
85
86    // Static method called by jni.
87    private static String mimeTypeFromExtension(String extension) {
88        return MimeUtils.guessMimeTypeFromExtension(extension);
89    }
90
91    /**
92     * Return true if the given extension has a registered MIME type.
93     * @param extension A file extension without the leading '.'
94     * @return True iff there is an extension entry in the map.
95     */
96    public boolean hasExtension(String extension) {
97        return MimeUtils.hasExtension(extension);
98    }
99
100    /**
101     * Return the registered extension for the given MIME type. Note that some
102     * MIME types map to multiple extensions. This call will return the most
103     * common extension for the given MIME type.
104     * @param mimeType A MIME type (i.e. text/plain)
105     * @return The extension for the given MIME type or null iff there is none.
106     */
107    public String getExtensionFromMimeType(String mimeType) {
108        return MimeUtils.guessExtensionFromMimeType(mimeType);
109    }
110
111    /**
112     * Get the singleton instance of MimeTypeMap.
113     * @return The singleton instance of the MIME-type map.
114     */
115    public static MimeTypeMap getSingleton() {
116        return sMimeTypeMap;
117    }
118}
119