1 /*
2  * Copyright (C) 2010 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 
17 package com.android.email.mail.store.imap;
18 
19 import com.android.emailcommon.Logging;
20 import com.android.mail.utils.LogUtils;
21 
22 import java.io.ByteArrayInputStream;
23 import java.io.InputStream;
24 import java.text.ParseException;
25 import java.text.SimpleDateFormat;
26 import java.util.Date;
27 import java.util.Locale;
28 
29 /**
30  * Class represents an IMAP "element" that is not a list.
31  *
32  * An atom, quoted string, literal, are all represented by this.  Values like OK, STATUS are too.
33  * Also, this class class may contain more arbitrary value like "BODY[HEADER.FIELDS ("DATE")]".
34  * See {@link ImapResponseParser}.
35  */
36 public abstract class ImapString extends ImapElement {
37     private static final byte[] EMPTY_BYTES = new byte[0];
38 
39     public static final ImapString EMPTY = new ImapString() {
40         @Override public void destroy() {
41             // Don't call super.destroy().
42             // It's a shared object.  We don't want the mDestroyed to be set on this.
43         }
44 
45         @Override public String getString() {
46             return "";
47         }
48 
49         @Override public InputStream getAsStream() {
50             return new ByteArrayInputStream(EMPTY_BYTES);
51         }
52 
53         @Override public String toString() {
54             return "";
55         }
56     };
57 
58     // This is used only for parsing IMAP's FETCH ENVELOPE command, in which
59     // en_US-like date format is used like "01-Jan-2009 11:20:39 -0800", so this should be
60     // handled by Locale.US
61     private final static SimpleDateFormat DATE_TIME_FORMAT =
62             new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss Z", Locale.US);
63 
64     private boolean mIsInteger;
65     private int mParsedInteger;
66     private Date mParsedDate;
67 
68     @Override
isList()69     public final boolean isList() {
70         return false;
71     }
72 
73     @Override
isString()74     public final boolean isString() {
75         return true;
76     }
77 
78     /**
79      * @return true if and only if the length of the string is larger than 0.
80      *
81      * Note: IMAP NIL is considered an empty string. See {@link ImapResponseParser
82      * #parseBareString}.
83      * On the other hand, a quoted/literal string with value NIL (i.e. "NIL" and {3}\r\nNIL) is
84      * treated literally.
85      */
isEmpty()86     public final boolean isEmpty() {
87         return getString().length() == 0;
88     }
89 
getString()90     public abstract String getString();
91 
getAsStream()92     public abstract InputStream getAsStream();
93 
94     /**
95      * @return whether it can be parsed as a number.
96      */
isNumber()97     public final boolean isNumber() {
98         if (mIsInteger) {
99             return true;
100         }
101         try {
102             mParsedInteger = Integer.parseInt(getString());
103             mIsInteger = true;
104             return true;
105         } catch (NumberFormatException e) {
106             return false;
107         }
108     }
109 
110     /**
111      * @return value parsed as a number.
112      */
getNumberOrZero()113     public final int getNumberOrZero() {
114         if (!isNumber()) {
115             return 0;
116         }
117         return mParsedInteger;
118     }
119 
120     /**
121      * @return whether it can be parsed as a date using {@link #DATE_TIME_FORMAT}.
122      */
isDate()123     public final boolean isDate() {
124         if (mParsedDate != null) {
125             return true;
126         }
127         if (isEmpty()) {
128             return false;
129         }
130         try {
131             mParsedDate = DATE_TIME_FORMAT.parse(getString());
132             return true;
133         } catch (ParseException e) {
134             LogUtils.w(Logging.LOG_TAG, getString() + " can't be parsed as a date.");
135             return false;
136         }
137     }
138 
139     /**
140      * @return value it can be parsed as a {@link Date}, or null otherwise.
141      */
getDateOrNull()142     public final Date getDateOrNull() {
143         if (!isDate()) {
144             return null;
145         }
146         return mParsedDate;
147     }
148 
149     /**
150      * @return whether the value case-insensitively equals to {@code s}.
151      */
is(String s)152     public final boolean is(String s) {
153         if (s == null) {
154             return false;
155         }
156         return getString().equalsIgnoreCase(s);
157     }
158 
159 
160     /**
161      * @return whether the value case-insensitively starts with {@code s}.
162      */
startsWith(String prefix)163     public final boolean startsWith(String prefix) {
164         if (prefix == null) {
165             return false;
166         }
167         final String me = this.getString();
168         if (me.length() < prefix.length()) {
169             return false;
170         }
171         return me.substring(0, prefix.length()).equalsIgnoreCase(prefix);
172     }
173 
174     // To force subclasses to implement it.
175     @Override
toString()176     public abstract String toString();
177 
178     @Override
equalsForTest(ImapElement that)179     public final boolean equalsForTest(ImapElement that) {
180         if (!super.equalsForTest(that)) {
181             return false;
182         }
183         ImapString thatString = (ImapString) that;
184         return getString().equals(thatString.getString());
185     }
186 }
187