1/*
2 * Copyright (C) 2011 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 com.android.email.mail.store.imap;
18
19import com.android.emailcommon.Logging;
20import com.android.mail.utils.LogUtils;
21
22import java.util.ArrayList;
23
24/**
25 * Utility methods for use with IMAP.
26 */
27public class ImapUtility {
28    /**
29     * Apply quoting rules per IMAP RFC,
30     * quoted          = DQUOTE *QUOTED-CHAR DQUOTE
31     * QUOTED-CHAR     = <any TEXT-CHAR except quoted-specials> / "\" quoted-specials
32     * quoted-specials = DQUOTE / "\"
33     *
34     * This is used primarily for IMAP login, but might be useful elsewhere.
35     *
36     * NOTE:  Not very efficient - you may wish to preflight this, or perhaps it should check
37     * for trouble chars before calling the replace functions.
38     *
39     * @param s The string to be quoted.
40     * @return A copy of the string, having undergone quoting as described above
41     */
42    public static String imapQuoted(String s) {
43
44        // First, quote any backslashes by replacing \ with \\
45        // regex Pattern:  \\    (Java string const = \\\\)
46        // Substitute:     \\\\  (Java string const = \\\\\\\\)
47        String result = s.replaceAll("\\\\", "\\\\\\\\");
48
49        // Then, quote any double-quotes by replacing " with \"
50        // regex Pattern:  "    (Java string const = \")
51        // Substitute:     \\"  (Java string const = \\\\\")
52        result = result.replaceAll("\"", "\\\\\"");
53
54        // return string with quotes around it
55        return "\"" + result + "\"";
56    }
57
58    /**
59     * Gets all of the values in a sequence set per RFC 3501. Any ranges are expanded into a
60     * list of individual numbers. If the set is invalid, an empty array is returned.
61     * <pre>
62     * sequence-number = nz-number / "*"
63     * sequence-range  = sequence-number ":" sequence-number
64     * sequence-set    = (sequence-number / sequence-range) *("," sequence-set)
65     * </pre>
66     */
67    public static String[] getImapSequenceValues(String set) {
68        ArrayList<String> list = new ArrayList<String>();
69        if (set != null) {
70            String[] setItems = set.split(",");
71            for (String item : setItems) {
72                if (item.indexOf(':') == -1) {
73                    // simple item
74                    try {
75                        Integer.parseInt(item); // Don't need the value; just ensure it's valid
76                        list.add(item);
77                    } catch (NumberFormatException e) {
78                        LogUtils.d(Logging.LOG_TAG, "Invalid UID value", e);
79                    }
80                } else {
81                    // range
82                    for (String rangeItem : getImapRangeValues(item)) {
83                        list.add(rangeItem);
84                    }
85                }
86            }
87        }
88        String[] stringList = new String[list.size()];
89        return list.toArray(stringList);
90    }
91
92    /**
93     * Expand the given number range into a list of individual numbers. If the range is not valid,
94     * an empty array is returned.
95     * <pre>
96     * sequence-number = nz-number / "*"
97     * sequence-range  = sequence-number ":" sequence-number
98     * sequence-set    = (sequence-number / sequence-range) *("," sequence-set)
99     * </pre>
100     */
101    public static String[] getImapRangeValues(String range) {
102        ArrayList<String> list = new ArrayList<String>();
103        try {
104            if (range != null) {
105                int colonPos = range.indexOf(':');
106                if (colonPos > 0) {
107                    int first  = Integer.parseInt(range.substring(0, colonPos));
108                    int second = Integer.parseInt(range.substring(colonPos + 1));
109                    if (first < second) {
110                        for (int i = first; i <= second; i++) {
111                            list.add(Integer.toString(i));
112                        }
113                    } else {
114                        for (int i = first; i >= second; i--) {
115                            list.add(Integer.toString(i));
116                        }
117                    }
118                }
119            }
120        } catch (NumberFormatException e) {
121            LogUtils.d(Logging.LOG_TAG, "Invalid range value", e);
122        }
123        String[] stringList = new String[list.size()];
124        return list.toArray(stringList);
125    }
126}
127