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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 
17 package com.android.ide.common.resources;
18 
19 import com.android.annotations.NonNull;
20 
21 import org.kxml2.io.KXmlParser;
22 import org.xmlpull.v1.XmlPullParser;
23 import org.xmlpull.v1.XmlPullParserException;
24 
25 import java.io.BufferedInputStream;
26 import java.io.FileInputStream;
27 import java.io.IOException;
28 import java.io.InputStream;
29 
30 /**
31  * Parser for scanning an XML resource file and validating all framework
32  * attribute references in it. If an error is found, the associated context
33  * is marked as needing a full AAPT run.
34  */
35 public class ValidatingResourceParser {
36     private final boolean mIsFramework;
37     private ScanningContext mContext;
38 
39     /**
40      * Creates a new {@link ValidatingResourceParser}
41      *
42      * @param context a context object with state for the current update, such
43      *            as a place to stash errors encountered
44      * @param isFramework true if scanning a framework resource
45      */
ValidatingResourceParser( @onNull ScanningContext context, boolean isFramework)46     public ValidatingResourceParser(
47             @NonNull ScanningContext context,
48             boolean isFramework) {
49         mContext = context;
50         mIsFramework = isFramework;
51     }
52 
53     /**
54      * Parse the given input and return false if it contains errors, <b>or</b> if
55      * the context is already tagged as needing a full aapt run.
56      *
57      * @param path the full OS path to the file being parsed
58      * @param input the input stream of the XML to be parsed
59      * @return true if parsing succeeds and false if it fails
60      * @throws IOException if reading the contents fails
61      */
parse(final String path, InputStream input)62     public boolean parse(final String path, InputStream input)
63             throws IOException {
64         // No need to validate framework files
65         if (mIsFramework) {
66             return true;
67         }
68         if (mContext.needsFullAapt()) {
69             return false;
70         }
71 
72         KXmlParser parser = new KXmlParser();
73         try {
74             parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
75 
76             if (input instanceof FileInputStream) {
77                 input = new BufferedInputStream(input);
78             }
79             parser.setInput(input, "UTF-8"); //$NON-NLS-1$
80 
81             return parse(path, parser);
82         } catch (XmlPullParserException e) {
83             String message = e.getMessage();
84 
85             // Strip off position description
86             int index = message.indexOf("(position:"); //$NON-NLS-1$ (Hardcoded in KXml)
87             if (index != -1) {
88                 message = message.substring(0, index);
89             }
90 
91             String error = String.format("%1$s:%2$d: Error: %3$s", //$NON-NLS-1$
92                     path, parser.getLineNumber(), message);
93             mContext.addError(error);
94             return false;
95         } catch (RuntimeException e) {
96             // Some exceptions are thrown by the KXmlParser that are not XmlPullParserExceptions,
97             // such as this one:
98             //    java.lang.RuntimeException: Undefined Prefix: w in org.kxml2.io.KXmlParser@...
99             //        at org.kxml2.io.KXmlParser.adjustNsp(Unknown Source)
100             //        at org.kxml2.io.KXmlParser.parseStartTag(Unknown Source)
101             String message = e.getMessage();
102             String error = String.format("%1$s:%2$d: Error: %3$s", //$NON-NLS-1$
103                     path, parser.getLineNumber(), message);
104             mContext.addError(error);
105             return false;
106         }
107     }
108 
parse(String path, KXmlParser parser)109     private boolean parse(String path, KXmlParser parser)
110             throws XmlPullParserException, IOException {
111         boolean checkForErrors = !mIsFramework && !mContext.needsFullAapt();
112 
113         while (true) {
114             int event = parser.next();
115             if (event == XmlPullParser.START_TAG) {
116                 for (int i = 0, n = parser.getAttributeCount(); i < n; i++) {
117                     String attribute = parser.getAttributeName(i);
118                     String value = parser.getAttributeValue(i);
119                     assert value != null : attribute;
120 
121                     if (checkForErrors) {
122                         String uri = parser.getAttributeNamespace(i);
123                         if (!mContext.checkValue(uri, attribute, value)) {
124                             mContext.requestFullAapt();
125                             return false;
126                         }
127                     }
128                 }
129             } else if (event == XmlPullParser.END_DOCUMENT) {
130                 break;
131             }
132         }
133 
134         return true;
135     }
136 }
137