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Factored out the database cleaner.

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This commit is contained in:
akwizgran
2011-07-04 18:11:27 +01:00
parent 390b316724
commit eb752ada62
9 changed files with 242 additions and 49 deletions
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57
components/net/sf/briar/db/DatabaseComponentImpl.java
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@@ -19,12 +19,14 @@ import com.google.inject.Provider;
* Abstract superclass containing code shared by ReadWriteLockDatabaseComponent
* and SynchronizedDatabaseComponent.
*/
abstract class DatabaseComponentImpl<Txn> implements DatabaseComponent {
abstract class DatabaseComponentImpl<Txn> implements DatabaseComponent,
DatabaseCleaner.Callback {
private static final Logger LOG =
Logger.getLogger(DatabaseComponentImpl.class.getName());
protected final Database<Txn> db;
protected final DatabaseCleaner cleaner;
protected final Provider<Batch> batchProvider;
private final Object spaceLock = new Object();
@@ -33,10 +35,16 @@ abstract class DatabaseComponentImpl<Txn> implements DatabaseComponent {
private long timeOfLastCheck = 0L; // Locking: spaceLock
private volatile boolean writesAllowed = true;
DatabaseComponentImpl(Database<Txn> db, Provider<Batch> batchProvider) {
DatabaseComponentImpl(Database<Txn> db, DatabaseCleaner cleaner,
Provider<Batch> batchProvider) {
this.db = db;
this.cleaner = cleaner;
this.batchProvider = batchProvider;
startCleaner();
}
public void open(boolean resume) throws DbException {
db.open(resume);
cleaner.startCleaning();
}
/**
@@ -63,13 +71,7 @@ abstract class DatabaseComponentImpl<Txn> implements DatabaseComponent {
return sendability;
}
/**
* Checks how much free storage space is available to the database, and if
* necessary expires old messages until the free space is at least
* MIN_FREE_SPACE. While the free space is less than CRITICAL_FREE_SPACE,
* operations that attempt to store messages in the database will block.
*/
private void checkFreeSpaceAndClean() throws DbException {
public void checkFreeSpaceAndClean() throws DbException {
long freeSpace = db.getFreeSpace();
while(freeSpace < MIN_FREE_SPACE) {
// If disk space is critical, disable the storage of new messages
@@ -123,11 +125,7 @@ abstract class DatabaseComponentImpl<Txn> implements DatabaseComponent {
db.removeMessage(txn, id);
}
/**
* Returns true iff the amount of free storage space available to the
* database should be checked.
*/
private boolean shouldCheckFreeSpace() {
public boolean shouldCheckFreeSpace() {
synchronized(spaceLock) {
long now = System.currentTimeMillis();
if(bytesStoredSinceLastCheck > MAX_BYTES_BETWEEN_SPACE_CHECKS) {
@@ -149,35 +147,6 @@ abstract class DatabaseComponentImpl<Txn> implements DatabaseComponent {
return false;
}
/**
* Starts a new thread to monitor the amount of free storage space
* available to the database and expire old messages as necessary.
* <p>
* FIXME: The thread implementation should be factored out.
*/
private void startCleaner() {
Runnable cleaner = new Runnable() {
public void run() {
try {
while(true) {
if(shouldCheckFreeSpace()) {
checkFreeSpaceAndClean();
} else {
try {
Thread.sleep(CLEANER_SLEEP_MS);
} catch(InterruptedException ignored) {}
}
}
} catch(Throwable t) {
// FIXME: Work out what to do here
t.printStackTrace();
System.exit(1);
}
}
};
new Thread(cleaner).start();
}
/**
* If the given message is already in the database, marks it as seen by the
* sender and returns false. Otherwise stores the message, updates the