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      1 /*
      2  * Copyright (C) 2015 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 android.support.v7.mms;
     18 
     19 import android.util.Log;
     20 
     21 import org.xmlpull.v1.XmlPullParser;
     22 import org.xmlpull.v1.XmlPullParserException;
     23 
     24 import java.io.IOException;
     25 
     26 /**
     27  * Base class for a parser of XML resources
     28  */
     29 abstract class MmsXmlResourceParser {
     30     /**
     31      * Parse the content
     32      *
     33      * @throws IOException
     34      * @throws XmlPullParserException
     35      */
     36     protected abstract void parseRecord() throws IOException, XmlPullParserException;
     37 
     38     /**
     39      * Get the root tag of the content
     40      *
     41      * @return the text of root tag
     42      */
     43     protected abstract String getRootTag();
     44 
     45     private final StringBuilder mLogStringBuilder = new StringBuilder();
     46 
     47     protected final XmlPullParser mInputParser;
     48 
     49     protected MmsXmlResourceParser(XmlPullParser parser) {
     50         mInputParser = parser;
     51     }
     52 
     53     void parse() {
     54         try {
     55             // Find the first element
     56             if (advanceToNextEvent(XmlPullParser.START_TAG) != XmlPullParser.START_TAG) {
     57                 throw new XmlPullParserException("ApnsXmlProcessor: expecting start tag @"
     58                         + xmlParserDebugContext());
     59             }
     60             if (!getRootTag().equals(mInputParser.getName())) {
     61                 Log.w(MmsService.TAG, "Carrier config does not start with " + getRootTag());
     62                 return;
     63             }
     64             // We are at the start tag
     65             for (;;) {
     66                 int nextEvent;
     67                 // Skipping spaces
     68                 while ((nextEvent = mInputParser.next()) == XmlPullParser.TEXT);
     69                 if (nextEvent == XmlPullParser.START_TAG) {
     70                     // Parse one record
     71                     parseRecord();
     72                 } else if (nextEvent == XmlPullParser.END_TAG) {
     73                     break;
     74                 } else {
     75                     throw new XmlPullParserException("Expecting start or end tag @"
     76                             + xmlParserDebugContext());
     77                 }
     78             }
     79         } catch (IOException e) {
     80             Log.w(MmsService.TAG, "XmlResourceParser: I/O failure", e);
     81         } catch (XmlPullParserException e) {
     82             Log.w(MmsService.TAG, "XmlResourceParser: parsing failure", e);
     83         }
     84     }
     85 
     86     /**
     87      * Move XML parser forward to next event type or the end of doc
     88      *
     89      * @param eventType
     90      * @return The final event type we meet
     91      * @throws XmlPullParserException
     92      * @throws IOException
     93      */
     94     protected int advanceToNextEvent(int eventType) throws XmlPullParserException, IOException {
     95         for (;;) {
     96             int nextEvent = mInputParser.next();
     97             if (nextEvent == eventType
     98                     || nextEvent == XmlPullParser.END_DOCUMENT) {
     99                 return nextEvent;
    100             }
    101         }
    102     }
    103 
    104     /**
    105      * @return The debugging information of the parser's current position
    106      */
    107     protected String xmlParserDebugContext() {
    108         mLogStringBuilder.setLength(0);
    109         if (mInputParser != null) {
    110             try {
    111                 final int eventType = mInputParser.getEventType();
    112                 mLogStringBuilder.append(xmlParserEventString(eventType));
    113                 if (eventType == XmlPullParser.START_TAG
    114                         || eventType == XmlPullParser.END_TAG
    115                         || eventType == XmlPullParser.TEXT) {
    116                     mLogStringBuilder.append('<').append(mInputParser.getName());
    117                     for (int i = 0; i < mInputParser.getAttributeCount(); i++) {
    118                         mLogStringBuilder.append(' ')
    119                                 .append(mInputParser.getAttributeName(i))
    120                                 .append('=')
    121                                 .append(mInputParser.getAttributeValue(i));
    122                     }
    123                     mLogStringBuilder.append("/>");
    124                 }
    125                 return mLogStringBuilder.toString();
    126             } catch (XmlPullParserException e) {
    127                 Log.w(MmsService.TAG, "XmlResourceParser exception", e);
    128             }
    129         }
    130         return "Unknown";
    131     }
    132 
    133     private static String xmlParserEventString(int event) {
    134         switch (event) {
    135             case XmlPullParser.START_DOCUMENT: return "START_DOCUMENT";
    136             case XmlPullParser.END_DOCUMENT: return "END_DOCUMENT";
    137             case XmlPullParser.START_TAG: return "START_TAG";
    138             case XmlPullParser.END_TAG: return "END_TAG";
    139             case XmlPullParser.TEXT: return "TEXT";
    140         }
    141         return Integer.toString(event);
    142     }
    143 }
    144