zdm/envoy
zdm/envoy
Archived
3
Fork 0
Code Issues 22 Pull Requests Releases 1 Wiki Activity

Make LocalDB thread safe and simplify its API

Browse Source
This commit is contained in:
Kai S. K. Engelbart 2020-09-20 11:12:33 +02:00
parent be945fe3ee
commit d8ae8a65b8
2 changed files with 66 additions and 92 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

149
client/src/main/java/envoy/client/data/LocalDB.java
View File

@ -30,59 +30,55 @@ import dev.kske.eventbus.EventListener;
*/
public final class LocalDB implements EventListener {
// Data
private User user;
private Map<String, User> users = new HashMap<>();
private List<Chat> chats = new ArrayList<>();
private Map<String, User> users = Collections.synchronizedMap(new HashMap<>());
private List<Chat> chats = Collections.synchronizedList(new ArrayList<>());
private IDGenerator idGenerator;
private CacheMap cacheMap = new CacheMap();
private Instant lastSync = Instant.EPOCH;
private String authToken;
private File dbDir, userFile, idGeneratorFile, lastLoginFile, usersFile;
private FileLock instanceLock;
// State management
private Instant lastSync = Instant.EPOCH;
// Persistence
private File dbDir, userFile, idGeneratorFile, lastLoginFile, usersFile;
private FileLock instanceLock;
/**
* Constructs an empty local database. To serialize any user-specific data to
* the file system, call {@link LocalDB#initializeUserStorage()} first
* and then {@link LocalDB#save(boolean)}.
* the file system, call {@link LocalDB#save(boolean)}.
*
* @param dbDir the directory in which to persist data
* @throws IOException if {@code dbDir} is a file (and not a directory)
* @throws IOException if {@code dbDir} is a file (and not a directory)
* @throws EnvoyException if {@code dbDir} is in use by another Envoy instance
* @since Envoy Client v0.2-beta
*/
public LocalDB(File dbDir) throws IOException {
public LocalDB(File dbDir) throws IOException, EnvoyException {
this.dbDir = dbDir;
EventBus.getInstance().registerListener(this);
// Ensure that the database directory exists
if (!dbDir.exists()) {
dbDir.mkdirs();
} else if (!dbDir.isDirectory())
throw new IOException(String.format("LocalDBDir '%s' is not a directory!", dbDir.getAbsolutePath()));
} else if (!dbDir.isDirectory()) throw new IOException(String.format("LocalDBDir '%s' is not a directory!", dbDir.getAbsolutePath()));
// Lock the directory
lock();
// Initialize global files
idGeneratorFile = new File(dbDir, "id_gen.db");
lastLoginFile = new File(dbDir, "last_login.db");
usersFile = new File(dbDir, "users.db");
// Load global files
loadGlobalData();
// Initialize offline caches
cacheMap.put(Message.class, new Cache<>());
cacheMap.put(MessageStatusChange.class, new Cache<>());
}
/**
* Creates a database file for a user-specific list of chats.
*
* @throws IllegalStateException if the client user is not specified
* @since Envoy Client v0.1-alpha
*/
public void initializeUserStorage() {
if (user == null) throw new IllegalStateException("Client user is null, cannot initialize user storage");
userFile = new File(dbDir, user.getID() + ".db");
}
FileChannel fc;
/**
* Ensured that only one Envoy instance is using this local database by creating
* a lock file.
@ -91,9 +87,8 @@ public final class LocalDB implements EventListener {
* @throws EnvoyException if the lock cannot by acquired
* @since Envoy Client v0.2-beta
*/
public void lock() throws EnvoyException {
private synchronized void lock() throws EnvoyException {
File file = new File(dbDir, "instance.lock");
file.deleteOnExit();
try {
FileChannel fc = FileChannel.open(file.toPath(), StandardOpenOption.CREATE, StandardOpenOption.WRITE);
instanceLock = fc.tryLock();
@ -104,37 +99,24 @@ public final class LocalDB implements EventListener {
}
/**
* Stores all users. If the client user is specified, their chats will be stored
* as well. The message id generator will also be saved if present.
* Loads the local user registry {@code users.db}, the id generator
* {@code id_gen.db} and last login file {@code last_login.db}.
*
* @param isOnline determines which {@code lastSync} time stamp is saved
* @throws IOException if the saving process failed
* @since Envoy Client v0.3-alpha
* @since Envoy Client v0.2-beta
*/
public void save(boolean isOnline) throws IOException {
// Save users
SerializationUtils.write(usersFile, users);
// Save user data and last sync time stamp
if (user != null) SerializationUtils.write(userFile, chats, cacheMap, isOnline ? Instant.now() : lastSync);
// Save last login information
if (authToken != null) SerializationUtils.write(lastLoginFile, user, authToken);
// Save id generator
if (hasIDGenerator()) SerializationUtils.write(idGeneratorFile, idGenerator);
private synchronized void loadGlobalData() {
try {
try (var in = new ObjectInputStream(new FileInputStream(usersFile))) {
users = (Map<String, User>) in.readObject();
}
idGenerator = SerializationUtils.read(idGeneratorFile, IDGenerator.class);
try (var in = new ObjectInputStream(new FileInputStream(lastLoginFile))) {
user = (User) in.readObject();
authToken = (String) in.readObject();
}
} catch (IOException | ClassNotFoundException e) {}
}
/**
* Loads all user data.
*
* @throws ClassNotFoundException if the loading process failed
* @throws IOException if the loading process failed
* @since Envoy Client v0.3-alpha
*/
public void loadUsers() throws ClassNotFoundException, IOException { users = SerializationUtils.read(usersFile, HashMap.class); }
/**
* Loads all data of the client user.
*
@ -142,36 +124,15 @@ public final class LocalDB implements EventListener {
* @throws IOException if the loading process failed
* @since Envoy Client v0.3-alpha
*/
public void loadUserData() throws ClassNotFoundException, IOException {
public synchronized void loadUserData() throws ClassNotFoundException, IOException {
if (user == null) throw new IllegalStateException("Client user is null, cannot initialize user storage");
userFile = new File(dbDir, user.getID() + ".db");
try (var in = new ObjectInputStream(new FileInputStream(userFile))) {
chats = (ArrayList<Chat>) in.readObject();
chats = (List<Chat>) in.readObject();
cacheMap = (CacheMap) in.readObject();
lastSync = (Instant) in.readObject();
}
}
/**
* Loads the ID generator. Any exception thrown during this process is ignored.
*
* @since Envoy Client v0.3-alpha
*/
public void loadIDGenerator() {
try {
idGenerator = SerializationUtils.read(idGeneratorFile, IDGenerator.class);
} catch (ClassNotFoundException | IOException e) {}
}
/**
* Loads the last login information. Any exception thrown during this process is
* ignored.
*
* @since Envoy Client v0.2-beta
*/
public void loadLastLogin() {
try (var in = new ObjectInputStream(new FileInputStream(lastLoginFile))) {
user = (User) in.readObject();
authToken = (String) in.readObject();
} catch (ClassNotFoundException | IOException e) {}
synchronize();
}
/**
@ -180,7 +141,7 @@ public final class LocalDB implements EventListener {
*
* @since Envoy Client v0.1-beta
*/
public void synchronize() {
private void synchronize() {
user.getContacts().stream().filter(u -> u instanceof User && !users.containsKey(u.getName())).forEach(u -> users.put(u.getName(), (User) u));
users.put(user.getName(), user);
@ -197,11 +158,33 @@ public final class LocalDB implements EventListener {
.forEach(chats::add);
}
@Event
private void onNewAuthToken(NewAuthToken evt) {
authToken = evt.get();
/**
* Stores all users. If the client user is specified, their chats will be stored
* as well. The message id generator will also be saved if present.
*
* @param isOnline determines which {@code lastSync} time stamp is saved
* @throws IOException if the saving process failed
* @since Envoy Client v0.3-alpha
*/
public synchronized void save(boolean isOnline) throws IOException {
// Save users
SerializationUtils.write(usersFile, users);
// Save user data and last sync time stamp
if (user != null) SerializationUtils.write(userFile, chats, cacheMap, isOnline ? Instant.now() : lastSync);
// Save last login information
if (authToken != null) SerializationUtils.write(lastLoginFile, user, authToken);
// Save id generator
if (hasIDGenerator()) SerializationUtils.write(idGeneratorFile, idGenerator);
}
@Event
private void onNewAuthToken(NewAuthToken evt) { authToken = evt.get(); }
/**
* @return a {@code Map<String, User>} of all users stored locally with their
* user names as keys

9
client/src/main/java/envoy/client/ui/Startup.java
View File

@ -70,7 +70,6 @@ public final class Startup extends Application {
File localDBDir = new File(config.getHomeDirectory(), config.getLocalDB().getPath());
logger.info("Initializing LocalDB at " + localDBDir);
localDB = new LocalDB(localDBDir);
localDB.lock();
} catch (IOException | EnvoyException e) {
logger.log(Level.SEVERE, "Could not initialize local database: ", e);
new Alert(AlertType.ERROR, "Could not initialize local database!\n" + e).showAndWait();
@ -79,8 +78,6 @@ public final class Startup extends Application {
}
// Prepare handshake
localDB.loadIDGenerator();
localDB.loadLastLogin();
context.setLocalDB(localDB);
// Configure stage
@ -94,7 +91,6 @@ public final class Startup extends Application {
// Authenticate with token if present
if (localDB.getAuthToken() != null) {
logger.info("Attempting authentication with token...");
localDB.initializeUserStorage();
localDB.loadUserData();
if (!performHandshake(
LoginCredentials.loginWithToken(localDB.getUser().getName(), localDB.getAuthToken(), VERSION, localDB.getLastSync())))
@ -146,7 +142,6 @@ public final class Startup extends Application {
public static boolean attemptOfflineMode(String identifier) {
try {
// Try entering offline mode
localDB.loadUsers();
final User clientUser = localDB.getUsers().get(identifier);
if (clientUser == null) throw new EnvoyException("Could not enter offline mode: user name unknown");
client.setSender(clientUser);
@ -169,9 +164,7 @@ public final class Startup extends Application {
*/
public static Instant loadLastSync(String identifier) {
try {
localDB.loadUsers();
localDB.setUser(localDB.getUsers().get(identifier));
localDB.initializeUserStorage();
localDB.loadUserData();
} catch (final Exception e) {
// User storage empty, wrong user name etc. -> default lastSync
@ -186,7 +179,6 @@ public final class Startup extends Application {
// Initialize chats in local database
try {
localDB.initializeUserStorage();
localDB.loadUserData();
} catch (final FileNotFoundException e) {
// The local database file has not yet been created, probably first login
@ -196,7 +188,6 @@ public final class Startup extends Application {
}
context.initWriteProxy();
localDB.synchronize();
if (client.isOnline()) context.getWriteProxy().flushCache();
else