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1 /*
2  * Copyright (C) 2014 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.provider;
18 
19 import android.content.ContentResolver;
20 import android.content.Context;
21 import android.database.Cursor;
22 import android.database.CursorWrapper;
23 import android.net.Uri;
24 import android.provider.BaseColumns;
25 import android.util.SparseArray;
26 
27 import com.android.emailcommon.provider.EmailContent.Body;
28 import com.android.mail.utils.HtmlSanitizer;
29 import com.android.mail.utils.LogUtils;
30 
31 import org.apache.commons.io.IOUtils;
32 
33 import java.io.IOException;
34 import java.io.InputStream;
35 
36 /**
37  * This class wraps a cursor for the purpose of bypassing the CursorWindow object for the
38  * potentially over-sized body content fields. The CursorWindow has a hard limit of 2MB and so a
39  * large email message can exceed that limit and cause the cursor to fail to load.
40  *
41  * To get around this, we load null values in those columns, and then in this wrapper we directly
42  * load the content from the provider, skipping the cursor window.
43  *
44  * This will still potentially blow up if this cursor gets wrapped in a CrossProcessCursorWrapper
45  * which uses a CursorWindow to shuffle results between processes. Since we're only using this for
46  * passing a cursor back to UnifiedEmail this shouldn't be an issue.
47  */
48 public class EmailMessageCursor extends CursorWrapper {
49 
50     private final SparseArray<String> mTextParts;
51     private final SparseArray<String> mHtmlParts;
52     private final int mTextColumnIndex;
53     private final int mHtmlColumnIndex;
54 
EmailMessageCursor(final Context c, final Cursor cursor, final String htmlColumn, final String textColumn)55     public EmailMessageCursor(final Context c, final Cursor cursor, final String htmlColumn,
56             final String textColumn) {
57         super(cursor);
58         mHtmlColumnIndex = cursor.getColumnIndex(htmlColumn);
59         mTextColumnIndex = cursor.getColumnIndex(textColumn);
60         final int cursorSize = cursor.getCount();
61         mHtmlParts = new SparseArray<String>(cursorSize);
62         mTextParts = new SparseArray<String>(cursorSize);
63 
64         final ContentResolver cr = c.getContentResolver();
65 
66         while (cursor.moveToNext()) {
67             final int position = cursor.getPosition();
68             final long messageId = cursor.getLong(cursor.getColumnIndex(BaseColumns._ID));
69             try {
70                 if (mHtmlColumnIndex != -1) {
71                     final Uri htmlUri = Body.getBodyHtmlUriForMessageWithId(messageId);
72                     final InputStream in = cr.openInputStream(htmlUri);
73                     final String underlyingHtmlString;
74                     try {
75                         underlyingHtmlString = IOUtils.toString(in);
76                     } finally {
77                         in.close();
78                     }
79                     final String sanitizedHtml = HtmlSanitizer.sanitizeHtml(underlyingHtmlString);
80                     mHtmlParts.put(position, sanitizedHtml);
81                 }
82             } catch (final IOException e) {
83                 LogUtils.v(LogUtils.TAG, e, "Did not find html body for message %d", messageId);
84             }
85             try {
86                 if (mTextColumnIndex != -1) {
87                     final Uri textUri = Body.getBodyTextUriForMessageWithId(messageId);
88                     final InputStream in = cr.openInputStream(textUri);
89                     final String underlyingTextString;
90                     try {
91                         underlyingTextString = IOUtils.toString(in);
92                     } finally {
93                         in.close();
94                     }
95                     mTextParts.put(position, underlyingTextString);
96                 }
97             } catch (final IOException e) {
98                 LogUtils.v(LogUtils.TAG, e, "Did not find text body for message %d", messageId);
99             }
100         }
101         cursor.moveToPosition(-1);
102     }
103 
104     @Override
getString(final int columnIndex)105     public String getString(final int columnIndex) {
106         if (columnIndex == mHtmlColumnIndex) {
107             return mHtmlParts.get(getPosition());
108         } else if (columnIndex == mTextColumnIndex) {
109             return mTextParts.get(getPosition());
110         }
111         return super.getString(columnIndex);
112     }
113 
114     @Override
getType(int columnIndex)115     public int getType(int columnIndex) {
116         if (columnIndex == mHtmlColumnIndex || columnIndex == mTextColumnIndex) {
117             // Need to force this, otherwise we might fall through to some other get*() method
118             // instead of getString() if the underlying cursor has other ideas about this content
119             return FIELD_TYPE_STRING;
120         } else {
121             return super.getType(columnIndex);
122         }
123     }
124 }
125