public void unsubscribe(USK origUSK, USKCallback cb) {
USKFetcher toCancel = null;
synchronized (this) {
USK clear = origUSK.clearCopy();
USKCallback[] callbacks = subscribersByClearUSK.get(clear);
if (callbacks
== null) { // maybe we should throw something ? shall we allow multiple unsubscriptions ?
if (logMINOR) Logger.minor(this, "No longer subscribed");
return;
}
int j = 0;
for (USKCallback c : callbacks) {
if ((c != null) && (c != cb)) {
callbacks[j++] = c;
}
}
USKCallback[] newCallbacks = Arrays.copyOf(callbacks, j);
if (newCallbacks.length > 0) subscribersByClearUSK.put(clear, newCallbacks);
else {
subscribersByClearUSK.remove(clear);
}
USKFetcher f = backgroundFetchersByClearUSK.get(clear);
if (f != null) {
f.removeSubscriber(cb, context);
if (!f.hasSubscribers()) {
toCancel = f;
backgroundFetchersByClearUSK.remove(clear);
}
}
// Temporary background fetchers run once and then die.
// They do not care about callbacks.
}
if (toCancel != null) {
toCancel.cancel(null, context);
} else {
if (logMINOR) Logger.minor(this, "Not found unsubscribing: " + cb + " for " + origUSK);
}
}
public void onFinished(USKFetcher fetcher, boolean ignoreError) {
USK orig = fetcher.getOriginalUSK();
USK clear = orig.clearCopy();
synchronized (this) {
if (backgroundFetchersByClearUSK.get(clear) == fetcher) {
backgroundFetchersByClearUSK.remove(clear);
if (!ignoreError) {
// This shouldn't happen, it's a sanity check: the only way we get cancelled is from
// USKManager, which removes us before calling cancel().
Logger.error(
this,
"onCancelled for " + fetcher + " - was still registered, how did this happen??",
new Exception("debug"));
}
}
if (temporaryBackgroundFetchersLRU.get(clear) == fetcher) {
temporaryBackgroundFetchersLRU.removeKey(clear);
temporaryBackgroundFetchersPrefetch.remove(clear);
}
}
}
/**
* Subscribe to a given USK. Callback will be notified when it is updated. Note that this does not
* imply that the USK will be checked on a regular basis, unless runBackgroundFetch=true.
*/
public void subscribe(
USK origUSK,
USKCallback cb,
boolean runBackgroundFetch,
boolean ignoreUSKDatehints,
RequestClient client) {
if (logMINOR) Logger.minor(this, "Subscribing to " + origUSK + " for " + cb);
if (client.persistent())
throw new UnsupportedOperationException("USKManager subscriptions cannot be persistent");
USKFetcher sched = null;
long ed = origUSK.suggestedEdition;
if (ed < 0) {
Logger.error(this, "Subscribing to USK with negative edition number: " + ed);
ed = -ed;
}
long curEd;
curEd = lookupLatestSlot(origUSK);
long goodEd;
goodEd = lookupKnownGood(origUSK);
synchronized (this) {
USK clear = origUSK.clearCopy();
USKCallback[] callbacks = subscribersByClearUSK.get(clear);
if (callbacks == null) {
callbacks = new USKCallback[] {cb};
} else {
boolean mustAdd = true;
for (USKCallback callback : callbacks) {
if (callback == cb) {
// Already subscribed.
// But it may still be waiting for the callback.
if (!(curEd > ed || goodEd > ed)) return;
mustAdd = false;
}
}
if (mustAdd) {
callbacks = Arrays.copyOf(callbacks, callbacks.length + 1);
callbacks[callbacks.length - 1] = cb;
}
}
subscribersByClearUSK.put(clear, callbacks);
if (runBackgroundFetch) {
USKFetcher f = backgroundFetchersByClearUSK.get(clear);
if (f == null) {
f =
new USKFetcher(
origUSK,
this,
ignoreUSKDatehints ? backgroundFetchContextIgnoreDBR : backgroundFetchContext,
new USKFetcherWrapper(origUSK, RequestStarter.UPDATE_PRIORITY_CLASS, client),
3,
true,
false,
false);
sched = f;
backgroundFetchersByClearUSK.put(clear, f);
}
f.addSubscriber(cb, origUSK.suggestedEdition);
}
}
if (goodEd > ed)
cb.onFoundEdition(
goodEd, origUSK.copy(curEd), null, context, false, (short) -1, null, true, curEd > ed);
else if (curEd > ed)
cb.onFoundEdition(
curEd, origUSK.copy(curEd), null, context, false, (short) -1, null, false, false);
final USKFetcher fetcher = sched;
if (fetcher != null) {
executor.execute(
new Runnable() {
@Override
public void run() {
if (logMINOR) Logger.minor(this, "Starting " + fetcher);
fetcher.schedule(null, context);
}
},
"USKManager.schedule for " + fetcher);
}
}
public void startTemporaryBackgroundFetcher(
USK usk,
ClientContext context,
final FetchContext fctx,
boolean prefetchContent,
boolean realTimeFlag) {
final USK clear = usk.clearCopy();
USKFetcher sched = null;
ArrayList<USKFetcher> toCancel = null;
synchronized (this) {
// int x = 0;
// for(USK key: backgroundFetchersByClearUSK.keySet()) {
// System.err.println("Fetcher "+x+": "+key);
// x++;
// }
USKFetcher f = temporaryBackgroundFetchersLRU.get(clear);
if (f == null) {
f =
new USKFetcher(
usk,
this,
fctx.ignoreUSKDatehints ? backgroundFetchContextIgnoreDBR : backgroundFetchContext,
new USKFetcherWrapper(
usk, RequestStarter.UPDATE_PRIORITY_CLASS, realTimeFlag ? rcRT : rcBulk),
3,
false,
false,
false);
sched = f;
temporaryBackgroundFetchersLRU.push(clear, f);
} else {
f.addHintEdition(usk.suggestedEdition);
}
if (prefetchContent) {
long fetchTime = -1;
// If nothing in 60 seconds, try fetching the last known slot.
long slot = lookupLatestSlot(clear);
long good = lookupKnownGood(clear);
if (slot > -1 && good != slot) fetchTime = System.currentTimeMillis();
temporaryBackgroundFetchersPrefetch.put(clear, fetchTime);
if (logMINOR) Logger.minor(this, "Prefetch: set " + fetchTime + " for " + clear);
schedulePrefetchChecker();
}
temporaryBackgroundFetchersLRU.push(clear, f);
while (temporaryBackgroundFetchersLRU.size() > NodeClientCore.getMaxBackgroundUSKFetchers()) {
USKFetcher fetcher = temporaryBackgroundFetchersLRU.popValue();
temporaryBackgroundFetchersPrefetch.remove(fetcher.getOriginalUSK().clearCopy());
if (!fetcher.hasSubscribers()) {
if (toCancel == null) toCancel = new ArrayList<USKFetcher>(2);
toCancel.add(fetcher);
} else {
if (logMINOR)
Logger.minor(
this,
"Allowing temporary background fetcher to continue as it has subscribers... "
+ fetcher);
}
}
}
final ArrayList<USKFetcher> cancelled = toCancel;
final USKFetcher scheduleMe = sched;
// This is just a prefetching method. so it should not unnecessarily delay the parent, nor
// should it take important locks.
// So we should do the actual schedule/cancels off-thread.
// However, the above is done on-thread because a lot of the time it will already be running.
if (cancelled != null || sched != null) {
executor.execute(
new Runnable() {
@Override
public void run() {
if (cancelled != null) {
for (int i = 0; i < cancelled.size(); i++) {
USKFetcher fetcher = cancelled.get(i);
fetcher.cancel(null, USKManager.this.context);
}
}
if (scheduleMe != null) scheduleMe.schedule(null, USKManager.this.context);
}
});
}
}
