Mercurial > 510Connectbot

comparison src/com/five_ten_sg/connectbot/util/RobustSQLiteOpenHelper.java @ 0:0ce5cc452d02

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initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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-1:000000000000 0:0ce5cc452d02
1 /*
2 * ConnectBot: simple, powerful, open-source SSH client for Android
3 * Copyright 2007 Kenny Root, Jeffrey Sharkey
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package com.five_ten_sg.connectbot.util;
19
20 import java.util.LinkedList;
21 import java.util.List;
22
23 import android.content.Context;
24 import android.database.Cursor;
25 import android.database.sqlite.SQLiteDatabase;
26 import android.database.sqlite.SQLiteDatabase.CursorFactory;
27 import android.database.sqlite.SQLiteException;
28 import android.database.sqlite.SQLiteOpenHelper;
29
30 /**
31 * @author Kenny Root
32 *
33 */
34 public abstract class RobustSQLiteOpenHelper extends SQLiteOpenHelper {
35 private static List<String> mTableNames = new LinkedList<String>();
36 private static List<String> mIndexNames = new LinkedList<String>();
37
38 public RobustSQLiteOpenHelper(Context context, String name,
39 CursorFactory factory, int version) {
40 super(context, name, factory, version);
41 }
42
43 protected static void addTableName(String tableName) {
44 mTableNames.add(tableName);
45 }
46
47 protected static void addIndexName(String indexName) {
48 mIndexNames.add(indexName);
49 }
50
51 @Override
52 public void onCreate(SQLiteDatabase db) {
53 dropAllTables(db);
54 }
55
56 @Override
57 public final void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
58 try {
59 onRobustUpgrade(db, oldVersion, newVersion);
60 }
61 catch (SQLiteException e) {
62 // The database has entered an unknown state. Try to recover.
63 try {
64 regenerateTables(db);
65 }
66 catch (SQLiteException e2) {
67 dropAndCreateTables(db);
68 }
69 }
70 }
71
72 public abstract void onRobustUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) throws SQLiteException;
73
74 private void regenerateTables(SQLiteDatabase db) {
75 dropAllTablesWithPrefix(db, "OLD_");
76
77 for (String tableName : mTableNames)
78 db.execSQL("ALTER TABLE " + tableName + " RENAME TO OLD_"
79 + tableName);
80
81 onCreate(db);
82
83 for (String tableName : mTableNames)
84 repopulateTable(db, tableName);
85
86 dropAllTablesWithPrefix(db, "OLD_");
87 }
88
89 private void repopulateTable(SQLiteDatabase db, String tableName) {
90 String columns = getTableColumnNames(db, tableName);
91 StringBuilder sb = new StringBuilder();
92 sb.append("INSERT INTO ")
93 .append(tableName)
94 .append(" (")
95 .append(columns)
96 .append(") SELECT ")
97 .append(columns)
98 .append(" FROM OLD_")
99 .append(tableName);
100 String sql = sb.toString();
101 db.execSQL(sql);
102 }
103
104 private String getTableColumnNames(SQLiteDatabase db, String tableName) {
105 StringBuilder sb = new StringBuilder();
106 Cursor fields = db.rawQuery("PRAGMA table_info(" + tableName + ")", null);
107
108 while (fields.moveToNext()) {
109 if (!fields.isFirst())
110 sb.append(", ");
111
112 sb.append(fields.getString(1));
113 }
114
115 fields.close();
116 return sb.toString();
117 }
118
119 private void dropAndCreateTables(SQLiteDatabase db) {
120 dropAllTables(db);
121 onCreate(db);
122 }
123
124 private void dropAllTablesWithPrefix(SQLiteDatabase db, String prefix) {
125 for (String indexName : mIndexNames)
126 db.execSQL("DROP INDEX IF EXISTS " + prefix + indexName);
127
128 for (String tableName : mTableNames)
129 db.execSQL("DROP TABLE IF EXISTS " + prefix + tableName);
130 }
131
132 private void dropAllTables(SQLiteDatabase db) {
133 dropAllTablesWithPrefix(db, "");
134 }
135 }