Merge pull request #6264 from vespa-engine/revert-6260-revert-6256-hakonhall/move-timebudget-to-vespajlib-and-use-clock

Revert "Revert "Move TimeBudget to vespajlib and use Clock""

3 files changed, 70 insertions, 118 deletions

diff --git a/vespajlib/src/main/java/com/yahoo/time/TimeBudget.java b/vespajlib/src/main/java/com/yahoo/time/TimeBudget.java
new file mode 100644
index 00000000000..fa18cb5e467
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/time/TimeBudget.java
@@ -0,0 +1,65 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.time;
+
+import com.google.common.util.concurrent.UncheckedTimeoutException;
+
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+
+/**
+ * A TimeBudget can be used to track the time of an ongoing operation with a timeout.
+ *
+ * @author hakon
+ */
+public class TimeBudget {
+    private final Clock clock;
+    private final Instant start;
+    private final Duration timeout;
+
+    /** Returns a TimeBudget with a start time of now, and with the given timeout. */
+    public static TimeBudget fromNow(Clock clock, Duration timeout) {
+        return new TimeBudget(clock, clock.instant(), timeout);
+    }
+
+    private TimeBudget(Clock clock, Instant start, Duration timeout) {
+        this.clock = clock;
+        this.start = start;
+        this.timeout = makeNonNegative(timeout);
+    }
+
+    /** Returns time since start. */
+    public Duration timePassed() {
+        return nonNegativeBetween(start, clock.instant());
+    }
+
+    /** Returns the original timeout. */
+    public Duration originalTimeout() {
+        return timeout;
+    }
+
+    /**
+     * Returns the time until deadline.
+     *
+     * @return time until deadline. It's toMillis() is guaranteed to be positive.
+     * @throws UncheckedTimeoutException if the deadline has been reached or passed.
+     */
+    public Duration timeLeftOrThrow() {
+        Instant now = clock.instant();
+        Duration left = Duration.between(now, start.plus(timeout));
+        if (left.toMillis() <= 0) {
+            throw new UncheckedTimeoutException("Time since start " + nonNegativeBetween(start, now) +
+                    " exceeds timeout " + timeout);
+        }
+
+        return left;
+    }
+
+    private static Duration nonNegativeBetween(Instant start, Instant end) {
+        return makeNonNegative(Duration.between(start, end));
+    }
+
+    private static Duration makeNonNegative(Duration duration) {
+        return duration.isNegative() ? Duration.ZERO : duration;
+    }
+}
diff --git a/vespajlib/src/main/java/com/yahoo/time/WallClockSource.java b/vespajlib/src/main/java/com/yahoo/time/WallClockSource.java
deleted file mode 100644
index 8a77879adf5..00000000000
--- a/vespajlib/src/main/java/com/yahoo/time/WallClockSource.java
+++ /dev/null
@@ -1,118 +0,0 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.time;
-
-import com.google.common.annotations.Beta;
-
-/**
- * A source for high-resolution timestamps.
- *
- * @author arnej27959
- */
-
-@Beta
-public class WallClockSource {
-
-    private volatile long offset;
-
-    /**
-     * Obtain the current time in nanoseconds.
-     * The epoch is January 1, 1970 UTC just as for System.currentTimeMillis(),
-     * but with greater resolution.  Note that the absolute accuracy may be
-     * no better than currentTimeMills().
-     * @return nanoseconds since the epoch.
-     **/
-    public final long currentTimeNanos() {
-        return System.nanoTime() + offset;
-    }
-
-    /**
-     * Create a source with 1 millisecond accuracy at start.
-     **/
-    WallClockSource() {
-        long actual = System.currentTimeMillis();
-        actual *= 1000000;
-        this.offset = actual - System.nanoTime();
-        initialAdjust();
-    }
-
-    /** adjust the clock source from currentTimeMillis()
-     * to ensure that it is no more than 1 milliseconds off.
-     * @return true if we want adjust called again soon
-     **/
-    boolean adjust() {
-        long nanosB = System.nanoTime();
-        long actual = System.currentTimeMillis();
-        long nanosA = System.nanoTime();
-        if (nanosA - nanosB > 100000) {
-            return true; // not a good time to adjust, try again soon
-        }
-        return adjustOffset(nanosB, actual, nanosA);
-    }
-
-    private boolean adjustOffset(long before, long actual, long after) {
-        actual *= 1000000; // convert millis to nanos
-        if (actual > after + offset) {
-            // System.out.println("WallClockSource adjust UP "+(actual-after-offset));
-            offset = actual - after;
-            return true;
-        }
-        if (actual + 999999 < before + offset) {
-            // System.out.println("WallClockSource adjust DOWN "+(before+offset-actual-999999));
-            offset = actual + 999999 - before;
-            return true;
-        }
-        return false;
-    }
-
-    private void initialAdjust() {
-       for (int i = 0; i < 100; i++) {
-           long nanosB = System.nanoTime();
-           long actual = System.currentTimeMillis();
-           long nanosA = System.nanoTime();
-           adjustOffset(nanosB, actual, nanosA);
-       }
-    }
-
-
-    static private WallClockSource autoAdjustingInstance = new WallClockSource();
-
-    /**
-     * Get a WallClockSource which auto adjusts to wall clock time.
-     **/
-    static public WallClockSource get() {
-        autoAdjustingInstance.startAdjuster();
-        return autoAdjustingInstance;
-    }
-
-    private Thread adjuster;
-
-    private synchronized void startAdjuster() {
-        if (adjuster == null) {
-            adjuster = new AdjustThread();
-            adjuster.setDaemon(true);
-            adjuster.start();
-        }
-    }
-
-    private class AdjustThread extends Thread {
-        public void run() {
-            int millis = 0;
-            int nanos = 313373; // random number
-            while (true) {
-                try {
-                    sleep(millis, nanos);
-                    if (++millis > 4321) {
-                        millis = 1000; // do not sleep too long
-                    }
-                } catch (InterruptedException e) {
-                    return;
-                }
-                if (adjust()) {
-                    // adjust more often in case clock jumped
-                    millis = 0;
-                }
-            }
-        }
-    }
-
-}
diff --git a/vespajlib/src/main/java/com/yahoo/time/package-info.java b/vespajlib/src/main/java/com/yahoo/time/package-info.java
new file mode 100644
index 00000000000..1b24da17655
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/time/package-info.java
@@ -0,0 +1,5 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+@ExportPackage
+package com.yahoo.time;
+
+import com.yahoo.osgi.annotation.ExportPackage;