diff -r 67078b90e47b -r 1eee453c24c1 jdk/src/java.base/share/classes/java/util/concurrent/CompletableFuture.java
--- a/jdk/src/java.base/share/classes/java/util/concurrent/CompletableFuture.java Fri Aug 29 11:59:34 2014 -0700
+++ b/jdk/src/java.base/share/classes/java/util/concurrent/CompletableFuture.java Mon Sep 01 13:33:28 2014 +0200
@@ -50,7 +50,6 @@
import java.util.concurrent.CancellationException;
import java.util.concurrent.CompletionException;
import java.util.concurrent.CompletionStage;
-import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.LockSupport;
/**
@@ -77,9 +76,9 @@
* All async methods without an explicit Executor
* argument are performed using the {@link ForkJoinPool#commonPool()}
* (unless it does not support a parallelism level of at least two, in
- * which case, a new Thread is used). To simplify monitoring,
- * debugging, and tracking, all generated asynchronous tasks are
- * instances of the marker interface {@link
+ * which case, a new Thread is created to run each task). To simplify
+ * monitoring, debugging, and tracking, all generated asynchronous
+ * tasks are instances of the marker interface {@link
* AsynchronousCompletionTask}.
*
* All CompletionStage methods are implemented independently of
@@ -113,141 +112,1556 @@
/*
* Overview:
*
- * 1. Non-nullness of field result (set via CAS) indicates done.
- * An AltResult is used to box null as a result, as well as to
- * hold exceptions. Using a single field makes completion fast
- * and simple to detect and trigger, at the expense of a lot of
- * encoding and decoding that infiltrates many methods. One minor
- * simplification relies on the (static) NIL (to box null results)
- * being the only AltResult with a null exception field, so we
- * don't usually need explicit comparisons with NIL. The CF
- * exception propagation mechanics surrounding decoding rely on
- * unchecked casts of decoded results really being unchecked,
- * where user type errors are caught at point of use, as is
- * currently the case in Java. These are highlighted by using
- * SuppressWarnings-annotated temporaries.
+ * A CompletableFuture may have dependent completion actions,
+ * collected in a linked stack. It atomically completes by CASing
+ * a result field, and then pops off and runs those actions. This
+ * applies across normal vs exceptional outcomes, sync vs async
+ * actions, binary triggers, and various forms of completions.
+ *
+ * Non-nullness of field result (set via CAS) indicates done. An
+ * AltResult is used to box null as a result, as well as to hold
+ * exceptions. Using a single field makes completion simple to
+ * detect and trigger. Encoding and decoding is straightforward
+ * but adds to the sprawl of trapping and associating exceptions
+ * with targets. Minor simplifications rely on (static) NIL (to
+ * box null results) being the only AltResult with a null
+ * exception field, so we don't usually need explicit comparisons.
+ * Even though some of the generics casts are unchecked (see
+ * SuppressWarnings annotations), they are placed to be
+ * appropriate even if checked.
*
- * 2. Waiters are held in a Treiber stack similar to the one used
- * in FutureTask, Phaser, and SynchronousQueue. See their
- * internal documentation for algorithmic details.
+ * Dependent actions are represented by Completion objects linked
+ * as Treiber stacks headed by field "stack". There are Completion
+ * classes for each kind of action, grouped into single-input
+ * (UniCompletion), two-input (BiCompletion), projected
+ * (BiCompletions using either (not both) of two inputs), shared
+ * (CoCompletion, used by the second of two sources), zero-input
+ * source actions, and Signallers that unblock waiters. Class
+ * Completion extends ForkJoinTask to enable async execution
+ * (adding no space overhead because we exploit its "tag" methods
+ * to maintain claims). It is also declared as Runnable to allow
+ * usage with arbitrary executors.
+ *
+ * Support for each kind of CompletionStage relies on a separate
+ * class, along with two CompletableFuture methods:
+ *
+ * * A Completion class with name X corresponding to function,
+ * prefaced with "Uni", "Bi", or "Or". Each class contains
+ * fields for source(s), actions, and dependent. They are
+ * boringly similar, differing from others only with respect to
+ * underlying functional forms. We do this so that users don't
+ * encounter layers of adaptors in common usages. We also
+ * include "Relay" classes/methods that don't correspond to user
+ * methods; they copy results from one stage to another.
+ *
+ * * Boolean CompletableFuture method x(...) (for example
+ * uniApply) takes all of the arguments needed to check that an
+ * action is triggerable, and then either runs the action or
+ * arranges its async execution by executing its Completion
+ * argument, if present. The method returns true if known to be
+ * complete.
*
- * 3. Completions are also kept in a list/stack, and pulled off
- * and run when completion is triggered. (We could even use the
- * same stack as for waiters, but would give up the potential
- * parallelism obtained because woken waiters help release/run
- * others -- see method postComplete). Because post-processing
- * may race with direct calls, class Completion opportunistically
- * extends AtomicInteger so callers can claim the action via
- * compareAndSet(0, 1). The Completion.run methods are all
- * written a boringly similar uniform way (that sometimes includes
- * unnecessary-looking checks, kept to maintain uniformity).
- * There are enough dimensions upon which they differ that
- * attempts to factor commonalities while maintaining efficiency
- * require more lines of code than they would save.
+ * * Completion method tryFire(int mode) invokes the associated x
+ * method with its held arguments, and on success cleans up.
+ * The mode argument allows tryFire to be called twice (SYNC,
+ * then ASYNC); the first to screen and trap exceptions while
+ * arranging to execute, and the second when called from a
+ * task. (A few classes are not used async so take slightly
+ * different forms.) The claim() callback suppresses function
+ * invocation if already claimed by another thread.
+ *
+ * * CompletableFuture method xStage(...) is called from a public
+ * stage method of CompletableFuture x. It screens user
+ * arguments and invokes and/or creates the stage object. If
+ * not async and x is already complete, the action is run
+ * immediately. Otherwise a Completion c is created, pushed to
+ * x's stack (unless done), and started or triggered via
+ * c.tryFire. This also covers races possible if x completes
+ * while pushing. Classes with two inputs (for example BiApply)
+ * deal with races across both while pushing actions. The
+ * second completion is a CoCompletion pointing to the first,
+ * shared so that at most one performs the action. The
+ * multiple-arity methods allOf and anyOf do this pairwise to
+ * form trees of completions.
+ *
+ * Note that the generic type parameters of methods vary according
+ * to whether "this" is a source, dependent, or completion.
*
- * 4. The exported then/and/or methods do support a bit of
- * factoring (see doThenApply etc). They must cope with the
- * intrinsic races surrounding addition of a dependent action
- * versus performing the action directly because the task is
- * already complete. For example, a CF may not be complete upon
- * entry, so a dependent completion is added, but by the time it
- * is added, the target CF is complete, so must be directly
- * executed. This is all done while avoiding unnecessary object
- * construction in safe-bypass cases.
+ * Method postComplete is called upon completion unless the target
+ * is guaranteed not to be observable (i.e., not yet returned or
+ * linked). Multiple threads can call postComplete, which
+ * atomically pops each dependent action, and tries to trigger it
+ * via method tryFire, in NESTED mode. Triggering can propagate
+ * recursively, so NESTED mode returns its completed dependent (if
+ * one exists) for further processing by its caller (see method
+ * postFire).
+ *
+ * Blocking methods get() and join() rely on Signaller Completions
+ * that wake up waiting threads. The mechanics are similar to
+ * Treiber stack wait-nodes used in FutureTask, Phaser, and
+ * SynchronousQueue. See their internal documentation for
+ * algorithmic details.
+ *
+ * Without precautions, CompletableFutures would be prone to
+ * garbage accumulation as chains of Completions build up, each
+ * pointing back to its sources. So we null out fields as soon as
+ * possible (see especially method Completion.detach). The
+ * screening checks needed anyway harmlessly ignore null arguments
+ * that may have been obtained during races with threads nulling
+ * out fields. We also try to unlink fired Completions from
+ * stacks that might never be popped (see method postFire).
+ * Completion fields need not be declared as final or volatile
+ * because they are only visible to other threads upon safe
+ * publication.
*/
- // preliminaries
+ volatile Object result; // Either the result or boxed AltResult
+ volatile Completion stack; // Top of Treiber stack of dependent actions
+
+ final boolean internalComplete(Object r) { // CAS from null to r
+ return UNSAFE.compareAndSwapObject(this, RESULT, null, r);
+ }
+
+ final boolean casStack(Completion cmp, Completion val) {
+ return UNSAFE.compareAndSwapObject(this, STACK, cmp, val);
+ }
+
+ /** Returns true if successfully pushed c onto stack. */
+ final boolean tryPushStack(Completion c) {
+ Completion h = stack;
+ lazySetNext(c, h);
+ return UNSAFE.compareAndSwapObject(this, STACK, h, c);
+ }
+
+ /** Unconditionally pushes c onto stack, retrying if necessary. */
+ final void pushStack(Completion c) {
+ do {} while (!tryPushStack(c));
+ }
+
+ /* ------------- Encoding and decoding outcomes -------------- */
+
+ static final class AltResult { // See above
+ final Throwable ex; // null only for NIL
+ AltResult(Throwable x) { this.ex = x; }
+ }
- static final class AltResult {
- final Throwable ex; // null only for NIL
- AltResult(Throwable ex) { this.ex = ex; }
+ /** The encoding of the null value. */
+ static final AltResult NIL = new AltResult(null);
+
+ /** Completes with the null value, unless already completed. */
+ final boolean completeNull() {
+ return UNSAFE.compareAndSwapObject(this, RESULT, null,
+ NIL);
+ }
+
+ /** Returns the encoding of the given non-exceptional value. */
+ final Object encodeValue(T t) {
+ return (t == null) ? NIL : t;
+ }
+
+ /** Completes with a non-exceptional result, unless already completed. */
+ final boolean completeValue(T t) {
+ return UNSAFE.compareAndSwapObject(this, RESULT, null,
+ (t == null) ? NIL : t);
+ }
+
+ /**
+ * Returns the encoding of the given (non-null) exception as a
+ * wrapped CompletionException unless it is one already.
+ */
+ static AltResult encodeThrowable(Throwable x) {
+ return new AltResult((x instanceof CompletionException) ? x :
+ new CompletionException(x));
+ }
+
+ /** Completes with an exceptional result, unless already completed. */
+ final boolean completeThrowable(Throwable x) {
+ return UNSAFE.compareAndSwapObject(this, RESULT, null,
+ encodeThrowable(x));
}
- static final AltResult NIL = new AltResult(null);
+ /**
+ * Returns the encoding of the given (non-null) exception as a
+ * wrapped CompletionException unless it is one already. May
+ * return the given Object r (which must have been the result of a
+ * source future) if it is equivalent, i.e. if this is a simple
+ * relay of an existing CompletionException.
+ */
+ static Object encodeThrowable(Throwable x, Object r) {
+ if (!(x instanceof CompletionException))
+ x = new CompletionException(x);
+ else if (r instanceof AltResult && x == ((AltResult)r).ex)
+ return r;
+ return new AltResult(x);
+ }
- // Fields
+ /**
+ * Completes with the given (non-null) exceptional result as a
+ * wrapped CompletionException unless it is one already, unless
+ * already completed. May complete with the given Object r
+ * (which must have been the result of a source future) if it is
+ * equivalent, i.e. if this is a simple propagation of an
+ * existing CompletionException.
+ */
+ final boolean completeThrowable(Throwable x, Object r) {
+ return UNSAFE.compareAndSwapObject(this, RESULT, null,
+ encodeThrowable(x, r));
+ }
+
+ /**
+ * Returns the encoding of the given arguments: if the exception
+ * is non-null, encodes as AltResult. Otherwise uses the given
+ * value, boxed as NIL if null.
+ */
+ Object encodeOutcome(T t, Throwable x) {
+ return (x == null) ? (t == null) ? NIL : t : encodeThrowable(x);
+ }
- volatile Object result; // Either the result or boxed AltResult
- volatile WaitNode waiters; // Treiber stack of threads blocked on get()
- volatile CompletionNode completions; // list (Treiber stack) of completions
+ /**
+ * Returns the encoding of a copied outcome; if exceptional,
+ * rewraps as a CompletionException, else returns argument.
+ */
+ static Object encodeRelay(Object r) {
+ Throwable x;
+ return (((r instanceof AltResult) &&
+ (x = ((AltResult)r).ex) != null &&
+ !(x instanceof CompletionException)) ?
+ new AltResult(new CompletionException(x)) : r);
+ }
+
+ /**
+ * Completes with r or a copy of r, unless already completed.
+ * If exceptional, r is first coerced to a CompletionException.
+ */
+ final boolean completeRelay(Object r) {
+ return UNSAFE.compareAndSwapObject(this, RESULT, null,
+ encodeRelay(r));
+ }
- // Basic utilities for triggering and processing completions
+ /**
+ * Reports result using Future.get conventions.
+ */
+ private static T reportGet(Object r)
+ throws InterruptedException, ExecutionException {
+ if (r == null) // by convention below, null means interrupted
+ throw new InterruptedException();
+ if (r instanceof AltResult) {
+ Throwable x, cause;
+ if ((x = ((AltResult)r).ex) == null)
+ return null;
+ if (x instanceof CancellationException)
+ throw (CancellationException)x;
+ if ((x instanceof CompletionException) &&
+ (cause = x.getCause()) != null)
+ x = cause;
+ throw new ExecutionException(x);
+ }
+ @SuppressWarnings("unchecked") T t = (T) r;
+ return t;
+ }
/**
- * Removes and signals all waiting threads and runs all completions.
+ * Decodes outcome to return result or throw unchecked exception.
+ */
+ private static T reportJoin(Object r) {
+ if (r instanceof AltResult) {
+ Throwable x;
+ if ((x = ((AltResult)r).ex) == null)
+ return null;
+ if (x instanceof CancellationException)
+ throw (CancellationException)x;
+ if (x instanceof CompletionException)
+ throw (CompletionException)x;
+ throw new CompletionException(x);
+ }
+ @SuppressWarnings("unchecked") T t = (T) r;
+ return t;
+ }
+
+ /* ------------- Async task preliminaries -------------- */
+
+ /**
+ * A marker interface identifying asynchronous tasks produced by
+ * {@code async} methods. This may be useful for monitoring,
+ * debugging, and tracking asynchronous activities.
+ *
+ * @since 1.8
+ */
+ public static interface AsynchronousCompletionTask {
+ }
+
+ private static final boolean useCommonPool =
+ (ForkJoinPool.getCommonPoolParallelism() > 1);
+
+ /**
+ * Default executor -- ForkJoinPool.commonPool() unless it cannot
+ * support parallelism.
+ */
+ private static final Executor asyncPool = useCommonPool ?
+ ForkJoinPool.commonPool() : new ThreadPerTaskExecutor();
+
+ /** Fallback if ForkJoinPool.commonPool() cannot support parallelism */
+ static final class ThreadPerTaskExecutor implements Executor {
+ public void execute(Runnable r) { new Thread(r).start(); }
+ }
+
+ /**
+ * Null-checks user executor argument, and translates uses of
+ * commonPool to asyncPool in case parallelism disabled.
+ */
+ static Executor screenExecutor(Executor e) {
+ if (!useCommonPool && e == ForkJoinPool.commonPool())
+ return asyncPool;
+ if (e == null) throw new NullPointerException();
+ return e;
+ }
+
+ // Modes for Completion.tryFire. Signedness matters.
+ static final int SYNC = 0;
+ static final int ASYNC = 1;
+ static final int NESTED = -1;
+
+ /* ------------- Base Completion classes and operations -------------- */
+
+ @SuppressWarnings("serial")
+ abstract static class Completion extends ForkJoinTask
+ implements Runnable, AsynchronousCompletionTask {
+ volatile Completion next; // Treiber stack link
+
+ /**
+ * Performs completion action if triggered, returning a
+ * dependent that may need propagation, if one exists.
+ *
+ * @param mode SYNC, ASYNC, or NESTED
+ */
+ abstract CompletableFuture tryFire(int mode);
+
+ /** Returns true if possibly still triggerable. Used by cleanStack. */
+ abstract boolean isLive();
+
+ public final void run() { tryFire(ASYNC); }
+ public final boolean exec() { tryFire(ASYNC); return true; }
+ public final Void getRawResult() { return null; }
+ public final void setRawResult(Void v) {}
+ }
+
+ static void lazySetNext(Completion c, Completion next) {
+ UNSAFE.putOrderedObject(c, NEXT, next);
+ }
+
+ /**
+ * Pops and tries to trigger all reachable dependents. Call only
+ * when known to be done.
*/
final void postComplete() {
- WaitNode q; Thread t;
- while ((q = waiters) != null) {
- if (UNSAFE.compareAndSwapObject(this, WAITERS, q, q.next) &&
- (t = q.thread) != null) {
- q.thread = null;
- LockSupport.unpark(t);
+ /*
+ * On each step, variable f holds current dependents to pop
+ * and run. It is extended along only one path at a time,
+ * pushing others to avoid unbounded recursion.
+ */
+ CompletableFuture f = this; Completion h;
+ while ((h = f.stack) != null ||
+ (f != this && (h = (f = this).stack) != null)) {
+ CompletableFuture d; Completion t;
+ if (f.casStack(h, t = h.next)) {
+ if (t != null) {
+ if (f != this) {
+ pushStack(h);
+ continue;
+ }
+ h.next = null; // detach
+ }
+ f = (d = h.tryFire(NESTED)) == null ? this : d;
}
}
+ }
- CompletionNode h; Completion c;
- while ((h = completions) != null) {
- if (UNSAFE.compareAndSwapObject(this, COMPLETIONS, h, h.next) &&
- (c = h.completion) != null)
- c.run();
+ /** Traverses stack and unlinks dead Completions. */
+ final void cleanStack() {
+ for (Completion p = null, q = stack; q != null;) {
+ Completion s = q.next;
+ if (q.isLive()) {
+ p = q;
+ q = s;
+ }
+ else if (p == null) {
+ casStack(q, s);
+ q = stack;
+ }
+ else {
+ p.next = s;
+ if (p.isLive())
+ q = s;
+ else {
+ p = null; // restart
+ q = stack;
+ }
+ }
+ }
+ }
+
+ /* ------------- One-input Completions -------------- */
+
+ /** A Completion with a source, dependent, and executor. */
+ @SuppressWarnings("serial")
+ abstract static class UniCompletion extends Completion {
+ Executor executor; // executor to use (null if none)
+ CompletableFuture dep; // the dependent to complete
+ CompletableFuture src; // source for action
+
+ UniCompletion(Executor executor, CompletableFuture dep,
+ CompletableFuture src) {
+ this.executor = executor; this.dep = dep; this.src = src;
+ }
+
+ /**
+ * Returns true if action can be run. Call only when known to
+ * be triggerable. Uses FJ tag bit to ensure that only one
+ * thread claims ownership. If async, starts as task -- a
+ * later call to tryFire will run action.
+ */
+ final boolean claim() {
+ Executor e = executor;
+ if (compareAndSetForkJoinTaskTag((short)0, (short)1)) {
+ if (e == null)
+ return true;
+ executor = null; // disable
+ e.execute(this);
+ }
+ return false;
+ }
+
+ final boolean isLive() { return dep != null; }
+ }
+
+ /** Pushes the given completion (if it exists) unless done. */
+ final void push(UniCompletion c) {
+ if (c != null) {
+ while (result == null && !tryPushStack(c))
+ lazySetNext(c, null); // clear on failure
}
}
/**
- * Triggers completion with the encoding of the given arguments:
- * if the exception is non-null, encodes it as a wrapped
- * CompletionException unless it is one already. Otherwise uses
- * the given result, boxed as NIL if null.
+ * Post-processing by dependent after successful UniCompletion
+ * tryFire. Tries to clean stack of source a, and then either runs
+ * postComplete or returns this to caller, depending on mode.
*/
- final void internalComplete(T v, Throwable ex) {
- if (result == null)
- UNSAFE.compareAndSwapObject
- (this, RESULT, null,
- (ex == null) ? (v == null) ? NIL : v :
- new AltResult((ex instanceof CompletionException) ? ex :
- new CompletionException(ex)));
- postComplete(); // help out even if not triggered
+ final CompletableFuture postFire(CompletableFuture a, int mode) {
+ if (a != null && a.stack != null) {
+ if (mode < 0 || a.result == null)
+ a.cleanStack();
+ else
+ a.postComplete();
+ }
+ if (result != null && stack != null) {
+ if (mode < 0)
+ return this;
+ else
+ postComplete();
+ }
+ return null;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniApply extends UniCompletion {
+ Function fn;
+ UniApply(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ Function fn) {
+ super(executor, dep, src); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null ||
+ !d.uniApply(a = src, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; fn = null;
+ return d.postFire(a, mode);
+ }
+ }
+
+ final boolean uniApply(CompletableFuture a,
+ Function f,
+ UniApply c) {
+ Object r; Throwable x;
+ if (a == null || (r = a.result) == null || f == null)
+ return false;
+ tryComplete: if (result == null) {
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ completeThrowable(x, r);
+ break tryComplete;
+ }
+ r = null;
+ }
+ try {
+ if (c != null && !c.claim())
+ return false;
+ @SuppressWarnings("unchecked") S s = (S) r;
+ completeValue(f.apply(s));
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture uniApplyStage(
+ Executor e, Function f) {
+ if (f == null) throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.uniApply(this, f, null)) {
+ UniApply c = new UniApply(e, d, this, f);
+ push(c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniAccept extends UniCompletion {
+ Consumer fn;
+ UniAccept(Executor executor, CompletableFuture dep,
+ CompletableFuture src, Consumer fn) {
+ super(executor, dep, src); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null ||
+ !d.uniAccept(a = src, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; fn = null;
+ return d.postFire(a, mode);
+ }
+ }
+
+ final boolean uniAccept(CompletableFuture a,
+ Consumer f, UniAccept c) {
+ Object r; Throwable x;
+ if (a == null || (r = a.result) == null || f == null)
+ return false;
+ tryComplete: if (result == null) {
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ completeThrowable(x, r);
+ break tryComplete;
+ }
+ r = null;
+ }
+ try {
+ if (c != null && !c.claim())
+ return false;
+ @SuppressWarnings("unchecked") S s = (S) r;
+ f.accept(s);
+ completeNull();
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture uniAcceptStage(Executor e,
+ Consumer f) {
+ if (f == null) throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.uniAccept(this, f, null)) {
+ UniAccept c = new UniAccept(e, d, this, f);
+ push(c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniRun extends UniCompletion {
+ Runnable fn;
+ UniRun(Executor executor, CompletableFuture dep,
+ CompletableFuture src, Runnable fn) {
+ super(executor, dep, src); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null ||
+ !d.uniRun(a = src, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; fn = null;
+ return d.postFire(a, mode);
+ }
+ }
+
+ final boolean uniRun(CompletableFuture a, Runnable f, UniRun c) {
+ Object r; Throwable x;
+ if (a == null || (r = a.result) == null || f == null)
+ return false;
+ if (result == null) {
+ if (r instanceof AltResult && (x = ((AltResult)r).ex) != null)
+ completeThrowable(x, r);
+ else
+ try {
+ if (c != null && !c.claim())
+ return false;
+ f.run();
+ completeNull();
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture uniRunStage(Executor e, Runnable f) {
+ if (f == null) throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.uniRun(this, f, null)) {
+ UniRun c = new UniRun(e, d, this, f);
+ push(c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniWhenComplete extends UniCompletion {
+ BiConsumer fn;
+ UniWhenComplete(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ BiConsumer fn) {
+ super(executor, dep, src); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null ||
+ !d.uniWhenComplete(a = src, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; fn = null;
+ return d.postFire(a, mode);
+ }
+ }
+
+ final boolean uniWhenComplete(CompletableFuture a,
+ BiConsumer f,
+ UniWhenComplete c) {
+ Object r; T t; Throwable x = null;
+ if (a == null || (r = a.result) == null || f == null)
+ return false;
+ if (result == null) {
+ try {
+ if (c != null && !c.claim())
+ return false;
+ if (r instanceof AltResult) {
+ x = ((AltResult)r).ex;
+ t = null;
+ } else {
+ @SuppressWarnings("unchecked") T tr = (T) r;
+ t = tr;
+ }
+ f.accept(t, x);
+ if (x == null) {
+ internalComplete(r);
+ return true;
+ }
+ } catch (Throwable ex) {
+ if (x == null)
+ x = ex;
+ }
+ completeThrowable(x, r);
+ }
+ return true;
+ }
+
+ private CompletableFuture uniWhenCompleteStage(
+ Executor e, BiConsumer f) {
+ if (f == null) throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.uniWhenComplete(this, f, null)) {
+ UniWhenComplete c = new UniWhenComplete(e, d, this, f);
+ push(c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniHandle extends UniCompletion {
+ BiFunction fn;
+ UniHandle(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ BiFunction fn) {
+ super(executor, dep, src); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null ||
+ !d.uniHandle(a = src, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; fn = null;
+ return d.postFire(a, mode);
+ }
}
- /**
- * If triggered, helps release and/or process completions.
- */
- final void helpPostComplete() {
- if (result != null)
- postComplete();
+ final boolean uniHandle(CompletableFuture a,
+ BiFunction f,
+ UniHandle c) {
+ Object r; S s; Throwable x;
+ if (a == null || (r = a.result) == null || f == null)
+ return false;
+ if (result == null) {
+ try {
+ if (c != null && !c.claim())
+ return false;
+ if (r instanceof AltResult) {
+ x = ((AltResult)r).ex;
+ s = null;
+ } else {
+ x = null;
+ @SuppressWarnings("unchecked") S ss = (S) r;
+ s = ss;
+ }
+ completeValue(f.apply(s, x));
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture uniHandleStage(
+ Executor e, BiFunction f) {
+ if (f == null) throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.uniHandle(this, f, null)) {
+ UniHandle c = new UniHandle(e, d, this, f);
+ push(c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniExceptionally extends UniCompletion {
+ Function fn;
+ UniExceptionally(CompletableFuture dep, CompletableFuture src,
+ Function fn) {
+ super(null, dep, src); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) { // never ASYNC
+ // assert mode != ASYNC;
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null || !d.uniExceptionally(a = src, fn, this))
+ return null;
+ dep = null; src = null; fn = null;
+ return d.postFire(a, mode);
+ }
+ }
+
+ final boolean uniExceptionally(CompletableFuture a,
+ Function f,
+ UniExceptionally c) {
+ Object r; Throwable x;
+ if (a == null || (r = a.result) == null || f == null)
+ return false;
+ if (result == null) {
+ try {
+ if (r instanceof AltResult && (x = ((AltResult)r).ex) != null) {
+ if (c != null && !c.claim())
+ return false;
+ completeValue(f.apply(x));
+ } else
+ internalComplete(r);
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture uniExceptionallyStage(
+ Function f) {
+ if (f == null) throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (!d.uniExceptionally(this, f, null)) {
+ UniExceptionally c = new UniExceptionally(d, this, f);
+ push(c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniRelay extends UniCompletion { // for Compose
+ UniRelay(CompletableFuture dep, CompletableFuture src) {
+ super(null, dep, src);
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null || !d.uniRelay(a = src))
+ return null;
+ src = null; dep = null;
+ return d.postFire(a, mode);
+ }
+ }
+
+ final boolean uniRelay(CompletableFuture a) {
+ Object r;
+ if (a == null || (r = a.result) == null)
+ return false;
+ if (result == null) // no need to claim
+ completeRelay(r);
+ return true;
+ }
+
+ @SuppressWarnings("serial")
+ static final class UniCompose extends UniCompletion {
+ Function> fn;
+ UniCompose(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ Function> fn) {
+ super(executor, dep, src); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d; CompletableFuture a;
+ if ((d = dep) == null ||
+ !d.uniCompose(a = src, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; fn = null;
+ return d.postFire(a, mode);
+ }
+ }
+
+ final boolean uniCompose(
+ CompletableFuture a,
+ Function> f,
+ UniCompose c) {
+ Object r; Throwable x;
+ if (a == null || (r = a.result) == null || f == null)
+ return false;
+ tryComplete: if (result == null) {
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ completeThrowable(x, r);
+ break tryComplete;
+ }
+ r = null;
+ }
+ try {
+ if (c != null && !c.claim())
+ return false;
+ @SuppressWarnings("unchecked") S s = (S) r;
+ CompletableFuture g = f.apply(s).toCompletableFuture();
+ if (g.result == null || !uniRelay(g)) {
+ UniRelay copy = new UniRelay(this, g);
+ g.push(copy);
+ copy.tryFire(SYNC);
+ if (result == null)
+ return false;
+ }
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture uniComposeStage(
+ Executor e, Function> f) {
+ if (f == null) throw new NullPointerException();
+ Object r; Throwable x;
+ if (e == null && (r = result) != null) {
+ // try to return function result directly
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ return new CompletableFuture(encodeThrowable(x, r));
+ }
+ r = null;
+ }
+ try {
+ @SuppressWarnings("unchecked") T t = (T) r;
+ return f.apply(t).toCompletableFuture();
+ } catch (Throwable ex) {
+ return new CompletableFuture(encodeThrowable(ex));
+ }
+ }
+ CompletableFuture d = new CompletableFuture();
+ UniCompose c = new UniCompose(e, d, this, f);
+ push(c);
+ c.tryFire(SYNC);
+ return d;
+ }
+
+ /* ------------- Two-input Completions -------------- */
+
+ /** A Completion for an action with two sources */
+ @SuppressWarnings("serial")
+ abstract static class BiCompletion extends UniCompletion {
+ CompletableFuture snd; // second source for action
+ BiCompletion(Executor executor, CompletableFuture dep,
+ CompletableFuture src, CompletableFuture snd) {
+ super(executor, dep, src); this.snd = snd;
+ }
+ }
+
+ /** A Completion delegating to a BiCompletion */
+ @SuppressWarnings("serial")
+ static final class CoCompletion extends Completion {
+ BiCompletion base;
+ CoCompletion(BiCompletion base) { this.base = base; }
+ final CompletableFuture tryFire(int mode) {
+ BiCompletion c; CompletableFuture d;
+ if ((c = base) == null || (d = c.tryFire(mode)) == null)
+ return null;
+ base = null; // detach
+ return d;
+ }
+ final boolean isLive() {
+ BiCompletion c;
+ return (c = base) != null && c.dep != null;
+ }
+ }
+
+ /** Pushes completion to this and b unless both done. */
+ final void bipush(CompletableFuture b, BiCompletion c) {
+ if (c != null) {
+ Object r;
+ while ((r = result) == null && !tryPushStack(c))
+ lazySetNext(c, null); // clear on failure
+ if (b != null && b != this && b.result == null) {
+ Completion q = (r != null) ? c : new CoCompletion(c);
+ while (b.result == null && !b.tryPushStack(q))
+ lazySetNext(q, null); // clear on failure
+ }
+ }
+ }
+
+ /** Post-processing after successful BiCompletion tryFire. */
+ final CompletableFuture postFire(CompletableFuture a,
+ CompletableFuture b, int mode) {
+ if (b != null && b.stack != null) { // clean second source
+ if (mode < 0 || b.result == null)
+ b.cleanStack();
+ else
+ b.postComplete();
+ }
+ return postFire(a, mode);
+ }
+
+ @SuppressWarnings("serial")
+ static final class BiApply extends BiCompletion {
+ BiFunction fn;
+ BiApply(Executor executor, CompletableFuture dep,
+ CompletableFuture src, CompletableFuture snd,
+ BiFunction fn) {
+ super(executor, dep, src, snd); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d;
+ CompletableFuture a;
+ CompletableFuture b;
+ if ((d = dep) == null ||
+ !d.biApply(a = src, b = snd, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; snd = null; fn = null;
+ return d.postFire(a, b, mode);
+ }
}
- /* ------------- waiting for completions -------------- */
+ final boolean biApply(CompletableFuture a,
+ CompletableFuture b,
+ BiFunction f,
+ BiApply c) {
+ Object r, s; Throwable x;
+ if (a == null || (r = a.result) == null ||
+ b == null || (s = b.result) == null || f == null)
+ return false;
+ tryComplete: if (result == null) {
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ completeThrowable(x, r);
+ break tryComplete;
+ }
+ r = null;
+ }
+ if (s instanceof AltResult) {
+ if ((x = ((AltResult)s).ex) != null) {
+ completeThrowable(x, s);
+ break tryComplete;
+ }
+ s = null;
+ }
+ try {
+ if (c != null && !c.claim())
+ return false;
+ @SuppressWarnings("unchecked") R rr = (R) r;
+ @SuppressWarnings("unchecked") S ss = (S) s;
+ completeValue(f.apply(rr, ss));
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture biApplyStage(
+ Executor e, CompletionStage o,
+ BiFunction f) {
+ CompletableFuture b;
+ if (f == null || (b = o.toCompletableFuture()) == null)
+ throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.biApply(this, b, f, null)) {
+ BiApply c = new BiApply(e, d, this, b, f);
+ bipush(b, c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class BiAccept extends BiCompletion {
+ BiConsumer fn;
+ BiAccept(Executor executor, CompletableFuture dep,
+ CompletableFuture src, CompletableFuture snd,
+ BiConsumer fn) {
+ super(executor, dep, src, snd); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d;
+ CompletableFuture a;
+ CompletableFuture b;
+ if ((d = dep) == null ||
+ !d.biAccept(a = src, b = snd, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; snd = null; fn = null;
+ return d.postFire(a, b, mode);
+ }
+ }
+
+ final boolean biAccept(CompletableFuture a,
+ CompletableFuture b,
+ BiConsumer f,
+ BiAccept c) {
+ Object r, s; Throwable x;
+ if (a == null || (r = a.result) == null ||
+ b == null || (s = b.result) == null || f == null)
+ return false;
+ tryComplete: if (result == null) {
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ completeThrowable(x, r);
+ break tryComplete;
+ }
+ r = null;
+ }
+ if (s instanceof AltResult) {
+ if ((x = ((AltResult)s).ex) != null) {
+ completeThrowable(x, s);
+ break tryComplete;
+ }
+ s = null;
+ }
+ try {
+ if (c != null && !c.claim())
+ return false;
+ @SuppressWarnings("unchecked") R rr = (R) r;
+ @SuppressWarnings("unchecked") S ss = (S) s;
+ f.accept(rr, ss);
+ completeNull();
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture biAcceptStage(
+ Executor e, CompletionStage o,
+ BiConsumer f) {
+ CompletableFuture b;
+ if (f == null || (b = o.toCompletableFuture()) == null)
+ throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.biAccept(this, b, f, null)) {
+ BiAccept c = new BiAccept(e, d, this, b, f);
+ bipush(b, c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
- /** Number of processors, for spin control */
- static final int NCPU = Runtime.getRuntime().availableProcessors();
+ @SuppressWarnings("serial")
+ static final class BiRun extends BiCompletion {
+ Runnable fn;
+ BiRun(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ CompletableFuture snd,
+ Runnable fn) {
+ super(executor, dep, src, snd); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d;
+ CompletableFuture a;
+ CompletableFuture b;
+ if ((d = dep) == null ||
+ !d.biRun(a = src, b = snd, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; snd = null; fn = null;
+ return d.postFire(a, b, mode);
+ }
+ }
+
+ final boolean biRun(CompletableFuture a, CompletableFuture b,
+ Runnable f, BiRun c) {
+ Object r, s; Throwable x;
+ if (a == null || (r = a.result) == null ||
+ b == null || (s = b.result) == null || f == null)
+ return false;
+ if (result == null) {
+ if (r instanceof AltResult && (x = ((AltResult)r).ex) != null)
+ completeThrowable(x, r);
+ else if (s instanceof AltResult && (x = ((AltResult)s).ex) != null)
+ completeThrowable(x, s);
+ else
+ try {
+ if (c != null && !c.claim())
+ return false;
+ f.run();
+ completeNull();
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture biRunStage(Executor e, CompletionStage o,
+ Runnable f) {
+ CompletableFuture b;
+ if (f == null || (b = o.toCompletableFuture()) == null)
+ throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.biRun(this, b, f, null)) {
+ BiRun c = new BiRun<>(e, d, this, b, f);
+ bipush(b, c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class BiRelay extends BiCompletion { // for And
+ BiRelay(CompletableFuture dep,
+ CompletableFuture src,
+ CompletableFuture snd) {
+ super(null, dep, src, snd);
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d;
+ CompletableFuture a;
+ CompletableFuture b;
+ if ((d = dep) == null || !d.biRelay(a = src, b = snd))
+ return null;
+ src = null; snd = null; dep = null;
+ return d.postFire(a, b, mode);
+ }
+ }
+
+ boolean biRelay(CompletableFuture a, CompletableFuture b) {
+ Object r, s; Throwable x;
+ if (a == null || (r = a.result) == null ||
+ b == null || (s = b.result) == null)
+ return false;
+ if (result == null) {
+ if (r instanceof AltResult && (x = ((AltResult)r).ex) != null)
+ completeThrowable(x, r);
+ else if (s instanceof AltResult && (x = ((AltResult)s).ex) != null)
+ completeThrowable(x, s);
+ else
+ completeNull();
+ }
+ return true;
+ }
+
+ /** Recursively constructs a tree of completions. */
+ static CompletableFuture andTree(CompletableFuture[] cfs,
+ int lo, int hi) {
+ CompletableFuture d = new CompletableFuture();
+ if (lo > hi) // empty
+ d.result = NIL;
+ else {
+ CompletableFuture a, b;
+ int mid = (lo + hi) >>> 1;
+ if ((a = (lo == mid ? cfs[lo] :
+ andTree(cfs, lo, mid))) == null ||
+ (b = (lo == hi ? a : (hi == mid+1) ? cfs[hi] :
+ andTree(cfs, mid+1, hi))) == null)
+ throw new NullPointerException();
+ if (!d.biRelay(a, b)) {
+ BiRelay c = new BiRelay<>(d, a, b);
+ a.bipush(b, c);
+ c.tryFire(SYNC);
+ }
+ }
+ return d;
+ }
+
+ /* ------------- Projected (Ored) BiCompletions -------------- */
+
+ /** Pushes completion to this and b unless either done. */
+ final void orpush(CompletableFuture b, BiCompletion c) {
+ if (c != null) {
+ while ((b == null || b.result == null) && result == null) {
+ if (tryPushStack(c)) {
+ if (b != null && b != this && b.result == null) {
+ Completion q = new CoCompletion(c);
+ while (result == null && b.result == null &&
+ !b.tryPushStack(q))
+ lazySetNext(q, null); // clear on failure
+ }
+ break;
+ }
+ lazySetNext(c, null); // clear on failure
+ }
+ }
+ }
+
+ @SuppressWarnings("serial")
+ static final class OrApply extends BiCompletion {
+ Function fn;
+ OrApply(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ CompletableFuture snd,
+ Function fn) {
+ super(executor, dep, src, snd); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d;
+ CompletableFuture a;
+ CompletableFuture b;
+ if ((d = dep) == null ||
+ !d.orApply(a = src, b = snd, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; snd = null; fn = null;
+ return d.postFire(a, b, mode);
+ }
+ }
- /**
- * Heuristic spin value for waitingGet() before blocking on
- * multiprocessors
- */
- static final int SPINS = (NCPU > 1) ? 1 << 8 : 0;
+ final boolean orApply(CompletableFuture a,
+ CompletableFuture b,
+ Function f,
+ OrApply c) {
+ Object r; Throwable x;
+ if (a == null || b == null ||
+ ((r = a.result) == null && (r = b.result) == null) || f == null)
+ return false;
+ tryComplete: if (result == null) {
+ try {
+ if (c != null && !c.claim())
+ return false;
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ completeThrowable(x, r);
+ break tryComplete;
+ }
+ r = null;
+ }
+ @SuppressWarnings("unchecked") R rr = (R) r;
+ completeValue(f.apply(rr));
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture orApplyStage(
+ Executor e, CompletionStage o,
+ Function f) {
+ CompletableFuture b;
+ if (f == null || (b = o.toCompletableFuture()) == null)
+ throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.orApply(this, b, f, null)) {
+ OrApply c = new OrApply(e, d, this, b, f);
+ orpush(b, c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class OrAccept extends BiCompletion {
+ Consumer fn;
+ OrAccept(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ CompletableFuture snd,
+ Consumer fn) {
+ super(executor, dep, src, snd); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d;
+ CompletableFuture a;
+ CompletableFuture b;
+ if ((d = dep) == null ||
+ !d.orAccept(a = src, b = snd, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; snd = null; fn = null;
+ return d.postFire(a, b, mode);
+ }
+ }
+
+ final boolean orAccept(CompletableFuture a,
+ CompletableFuture b,
+ Consumer f,
+ OrAccept c) {
+ Object r; Throwable x;
+ if (a == null || b == null ||
+ ((r = a.result) == null && (r = b.result) == null) || f == null)
+ return false;
+ tryComplete: if (result == null) {
+ try {
+ if (c != null && !c.claim())
+ return false;
+ if (r instanceof AltResult) {
+ if ((x = ((AltResult)r).ex) != null) {
+ completeThrowable(x, r);
+ break tryComplete;
+ }
+ r = null;
+ }
+ @SuppressWarnings("unchecked") R rr = (R) r;
+ f.accept(rr);
+ completeNull();
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture orAcceptStage(
+ Executor e, CompletionStage o, Consumer f) {
+ CompletableFuture b;
+ if (f == null || (b = o.toCompletableFuture()) == null)
+ throw new NullPointerException();
+ CompletableFuture d = new CompletableFuture();
+ if (e != null || !d.orAccept(this, b, f, null)) {
+ OrAccept c = new OrAccept(e, d, this, b, f);
+ orpush(b, c);
+ c.tryFire(SYNC);
+ }
+ return d;
+ }
+
+ @SuppressWarnings("serial")
+ static final class OrRun extends BiCompletion {
+ Runnable fn;
+ OrRun(Executor executor, CompletableFuture dep,
+ CompletableFuture src,
+ CompletableFuture snd,
+ Runnable fn) {
+ super(executor, dep, src, snd); this.fn = fn;
+ }
+ final CompletableFuture tryFire(int mode) {
+ CompletableFuture d;
+ CompletableFuture a;
+ CompletableFuture b;
+ if ((d = dep) == null ||
+ !d.orRun(a = src, b = snd, fn, mode > 0 ? null : this))
+ return null;
+ dep = null; src = null; snd = null; fn = null;
+ return d.postFire(a, b, mode);
+ }
+ }
+
+ final boolean orRun(CompletableFuture a, CompletableFuture b,
+ Runnable f, OrRun c) {
+ Object r; Throwable x;
+ if (a == null || b == null ||
+ ((r = a.result) == null && (r = b.result) == null) || f == null)
+ return false;
+ if (result == null) {
+ try {
+ if (c != null && !c.claim())
+ return false;
+ if (r instanceof AltResult && (x = ((AltResult)r).ex) != null)
+ completeThrowable(x, r);
+ else {
+ f.run();
+ completeNull();
+ }
+ } catch (Throwable ex) {
+ completeThrowable(ex);
+ }
+ }
+ return true;
+ }
+
+ private CompletableFuture orRunStage(Executor e, CompletionStage o,
+ Runnable f) {
+ CompletableFuture b;
+ if (f == null || (b = o.toCompletableFuture()) == null)
+ throw new NullPointerException();
+ CompletableFuture