1 files changed, 97 insertions, 2 deletions

diff --git a/main/src/cgeo/geocaching/utils/RxUtils.java b/main/src/cgeo/geocaching/utils/RxUtils.java
index 241ba78..ef79f93 100644
--- a/main/src/cgeo/geocaching/utils/RxUtils.java
+++ b/main/src/cgeo/geocaching/utils/RxUtils.java
@@ -1,23 +1,49 @@
 package cgeo.geocaching.utils;
 
 import rx.Observable;
+import rx.Observable.OnSubscribe;
+import rx.Observable.Operator;
 import rx.Scheduler;
+import rx.Scheduler.Worker;
+import rx.Subscriber;
+import rx.android.schedulers.AndroidSchedulers;
+import rx.functions.Action0;
+import rx.functions.Func1;
+import rx.internal.operators.OperatorTakeWhile;
 import rx.observables.BlockingObservable;
 import rx.schedulers.Schedulers;
+import rx.subscriptions.Subscriptions;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.Looper;
 
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
 
 public class RxUtils {
 
-    // Utility class, not to be instanciated
-    private RxUtils() {}
+    private RxUtils() {
+        // Utility class, not to be instantiated
+    }
 
     public final static Scheduler computationScheduler = Schedulers.computation();
 
     public static final Scheduler networkScheduler = Schedulers.from(new ThreadPoolExecutor(10, 10, 5, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>()));
 
+    private static final HandlerThread looperCallbacksThread =
+            new HandlerThread("Looper callbacks thread", android.os.Process.THREAD_PRIORITY_BACKGROUND);
+
+    static {
+        looperCallbacksThread.start();
+    }
+
+    public static final Looper looperCallbacksLooper = looperCallbacksThread.getLooper();
+    public static final Scheduler looperCallbacksScheduler = AndroidSchedulers.handlerThread(new Handler(looperCallbacksLooper));
+    public static final Worker looperCallbacksWorker = looperCallbacksScheduler.createWorker();
+
     public static <T> void waitForCompletion(final BlockingObservable<T> observable) {
         observable.lastOrDefault(null);
     }
@@ -25,4 +51,73 @@ public class RxUtils {
     public static void waitForCompletion(final Observable<?>... observables) {
         waitForCompletion(Observable.merge(observables).toBlocking());
     }
+
+    /**
+     * Subscribe function whose subscription and unsubscription take place on a looper thread.
+     *
+     * @param <T>
+     *         the type of the observable
+     */
+    public static abstract class LooperCallbacks<T> implements OnSubscribe<T> {
+
+        final AtomicInteger counter = new AtomicInteger(0);
+        final long stopDelay;
+        final TimeUnit stopDelayUnit;
+        protected Subscriber<? super T> subscriber;
+
+        public LooperCallbacks(final long stopDelay, final TimeUnit stopDelayUnit) {
+            this.stopDelay = stopDelay;
+            this.stopDelayUnit = stopDelayUnit;
+        }
+
+        public LooperCallbacks() {
+            this(0, TimeUnit.SECONDS);
+        }
+
+        @Override
+        final public void call(final Subscriber<? super T> subscriber) {
+            this.subscriber = subscriber;
+            looperCallbacksWorker.schedule(new Action0() {
+                @Override
+                public void call() {
+                    if (counter.getAndIncrement() == 0) {
+                        onStart();
+                    }
+                    subscriber.add(Subscriptions.create(new Action0() {
+                        @Override
+                        public void call() {
+                            looperCallbacksWorker.schedule(new Action0() {
+                                @Override
+                                public void call() {
+                                    if (counter.decrementAndGet() == 0) {
+                                        onStop();
+                                    }
+                                }
+                            }, stopDelay, stopDelayUnit);
+                        }
+                    }));
+                }
+            });
+        }
+
+        abstract protected void onStart();
+
+        abstract protected void onStop();
+    }
+
+    public static <T> Operator<T, T> operatorTakeUntil(final Func1<? super T, Boolean> predicate) {
+        return new OperatorTakeWhile<>(new Func1<T, Boolean>() {
+            private boolean quitting = false;
+
+            @Override
+            public Boolean call(final T item) {
+                if (quitting) {
+                    return false;
+                }
+                quitting |= predicate.call(item);
+                return true;
+            }
+        });
+    }
+
 }