From 1ac8524dc29dceb7037b3e1fe39a43e8762c60c7 Mon Sep 17 00:00:00 2001
From: akwizgran <akwizgran@users.sourceforge.net>
Date: Tue, 4 Feb 2014 19:51:41 +0000
Subject: [PATCH] Allow the code and the DB to have different but compatible
schemas.
We check for compatibility by specifying a schema version and minimum
schema version in the code, storing them in the DB, and checking whether
the DB is too old for the code or vice versa.
---
briar-android/res/values/strings.xml | 2 +-
.../api/db/DbSchemaException.java | 10 ---
.../src/org/briarproject/db/JdbcDatabase.java | 64 +++++++++++--------
3 files changed, 39 insertions(+), 37 deletions(-)
delete mode 100644 briar-api/src/org/briarproject/api/db/DbSchemaException.java
diff --git a/briar-android/res/values/strings.xml b/briar-android/res/values/strings.xml
index a5a51a5188..9920a91944 100644
--- a/briar-android/res/values/strings.xml
+++ b/briar-android/res/values/strings.xml
@@ -15,7 +15,7 @@
<string name="passwords_do_not_match">Passwords do not match</string>
<string name="enter_password">Enter your password:</string>
<string name="try_again">Wrong password, try again:</string>
- <string name="startup_failed_notification_title">Briar could not start up</string>
+ <string name="startup_failed_notification_title">Briar could not start</string>
<string name="startup_failed_notification_text">You may need to reinstall Briar.</string>
<string name="expiry_warning">This software has expired.\nPlease install a newer version.</string>
<string name="contact_list_button">Contacts</string>
diff --git a/briar-api/src/org/briarproject/api/db/DbSchemaException.java b/briar-api/src/org/briarproject/api/db/DbSchemaException.java
deleted file mode 100644
index 79dc98533e..0000000000
--- a/briar-api/src/org/briarproject/api/db/DbSchemaException.java
+++ /dev/null
@@ -1,10 +0,0 @@
-package org.briarproject.api.db;
-
-/**
- * Thrown when the schema of the database differs from the schema expected by
- * the code.
- */
-public class DbSchemaException extends DbException {
-
- private static final long serialVersionUID = -4444069279533651710L;
-}
diff --git a/briar-core/src/org/briarproject/db/JdbcDatabase.java b/briar-core/src/org/briarproject/db/JdbcDatabase.java
index 004c0787b1..a2dd5ac86d 100644
--- a/briar-core/src/org/briarproject/db/JdbcDatabase.java
+++ b/briar-core/src/org/briarproject/db/JdbcDatabase.java
@@ -38,7 +38,6 @@ import org.briarproject.api.TransportId;
import org.briarproject.api.TransportProperties;
import org.briarproject.api.db.DbClosedException;
import org.briarproject.api.db.DbException;
-import org.briarproject.api.db.DbSchemaException;
import org.briarproject.api.db.MessageHeader;
import org.briarproject.api.messaging.Group;
import org.briarproject.api.messaging.GroupId;
@@ -61,7 +60,8 @@ import org.briarproject.api.transport.TemporarySecret;
*/
abstract class JdbcDatabase implements Database<Connection> {
- private static final int SCHEMA_VERSION = 2;
+ private static final int SCHEMA_VERSION = 3;
+ private static final int MIN_SCHEMA_VERSION = 3;
private static final String CREATE_SETTINGS =
"CREATE TABLE settings"
@@ -372,11 +372,13 @@ abstract class JdbcDatabase implements Database<Connection> {
Connection txn = startTransaction();
try {
if(reopen) {
- if(!checkSchemaVersion(txn))
- throw new DbSchemaException();
+ if(!checkSchemaVersion(txn)) throw new DbException();
} else {
createTables(txn);
- setSchemaVersion(txn);
+ String schemaVersion = String.valueOf(SCHEMA_VERSION);
+ setSetting(txn, "schemaVersion", schemaVersion);
+ String minSchemaVersion = String.valueOf(MIN_SCHEMA_VERSION);
+ setSetting(txn, "minSchemaVersion", minSchemaVersion);
}
commitTransaction(txn);
} catch(DbException e) {
@@ -386,27 +388,53 @@ abstract class JdbcDatabase implements Database<Connection> {
}
private boolean checkSchemaVersion(Connection txn) throws DbException {
+ try {
+ String value = getSetting(txn, "schemaVersion");
+ int schemaVersion = Integer.valueOf(value);
+ if(schemaVersion == SCHEMA_VERSION) return true;
+ if(schemaVersion < MIN_SCHEMA_VERSION) return false;
+ value = getSetting(txn, "minSchemaVersion");
+ int minSchemaVersion = Integer.valueOf(value);
+ return SCHEMA_VERSION >= minSchemaVersion;
+ } catch(NumberFormatException e) {
+ throw new DbException(e);
+ }
+ }
+
+ private String getSetting(Connection txn, String key) throws DbException {
PreparedStatement ps = null;
ResultSet rs = null;
- String value;
try {
String sql = "SELECT value FROM settings WHERE key = ?";
ps = txn.prepareStatement(sql);
- ps.setString(1, "schemaVersion");
+ ps.setString(1, key);
rs = ps.executeQuery();
if(!rs.next()) throw new DbStateException();
- value = rs.getString(1);
+ String value = rs.getString(1);
if(rs.next()) throw new DbStateException();
rs.close();
ps.close();
+ return value;
} catch(SQLException e) {
tryToClose(rs);
tryToClose(ps);
throw new DbException(e);
}
+ }
+
+ private void setSetting(Connection txn, String key, String value)
+ throws DbException {
+ PreparedStatement ps = null;
try {
- return Integer.valueOf(value) == SCHEMA_VERSION;
- } catch(NumberFormatException e) {
+ String sql = "INSERT INTO settings (key, value) VALUES (?, ?)";
+ ps = txn.prepareStatement(sql);
+ ps.setString(1, key);
+ ps.setString(2, value);
+ int affected = ps.executeUpdate();
+ if(affected < 1) throw new DbStateException();
+ ps.close();
+ } catch(SQLException e) {
+ tryToClose(ps);
throw new DbException(e);
}
}
@@ -469,22 +497,6 @@ abstract class JdbcDatabase implements Database<Connection> {
return s;
}
- private void setSchemaVersion(Connection txn) throws DbException {
- PreparedStatement ps = null;
- try {
- String sql = "INSERT INTO settings (key, value) VALUES (?, ?)";
- ps = txn.prepareStatement(sql);
- ps.setString(1, "schemaVersion");
- ps.setString(2, String.valueOf(SCHEMA_VERSION));
- int affected = ps.executeUpdate();
- if(affected != 1) throw new DbStateException();
- ps.close();
- } catch(SQLException e) {
- tryToClose(ps);
- throw new DbException(e);
- }
- }
-
public Connection startTransaction() throws DbException {
Connection txn = null;
synchronized(connections) {
--
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