Break circular dependency between core and util (#379)

* Break circular dependency between core and util

Created a new :common project and moved a minimum
number of classes to break the circular dependency
between the two projects. This gets rid of the
gradle lint dependency warnings.

Also separated api classes and testing helpers into
separate source sets in :common so that testing
classes may be restricted to test configurations.

common/src/main/java/google/registry/util/Clock.java

@@ -0,0 +1,34 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.util;
+
+import java.io.Serializable;
+import javax.annotation.concurrent.ThreadSafe;
+import org.joda.time.DateTime;
+
+/**
+ * A clock that tells the current time in milliseconds or nanoseconds.
+ *
+ * <p>Clocks are technically serializable because they are either a stateless wrapper around the
+ * system clock, or for testing, are just a wrapper around a DateTime. This means that if you
+ * serialize a clock and deserialize it elsewhere, you won't necessarily get the same time or time
+ * zone -- what you will get is a functioning clock.
+ */
+@ThreadSafe
+public interface Clock extends Serializable {
+
+  /** Returns current time in UTC timezone. */
+  DateTime nowUtc();
+}

common/src/main/java/google/registry/util/DateTimeUtils.java

@@ -0,0 +1,111 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.util;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Ordering;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.util.TimeZone;
+import org.joda.time.DateTime;
+import org.joda.time.DateTimeZone;
+
+/** Utilities methods and constants related to Joda {@link DateTime} objects. */
+public class DateTimeUtils {
+
+  /** The start of the epoch, in a convenient constant. */
+  public static final DateTime START_OF_TIME = new DateTime(0, DateTimeZone.UTC);
+
+  /**
+   * A date in the far future that we can treat as infinity.
+   *
+   * <p>This value is (2^63-1)/1000 rounded down. AppEngine stores dates as 64 bit microseconds, but
+   * Java uses milliseconds, so this is the largest representable date that will survive a
+   * round-trip through Datastore.
+   */
+  public static final DateTime END_OF_TIME = new DateTime(Long.MAX_VALUE / 1000, DateTimeZone.UTC);
+
+  /** Returns the earliest of a number of given {@link DateTime} instances. */
+  public static DateTime earliestOf(DateTime first, DateTime... rest) {
+    return earliestOf(Lists.asList(first, rest));
+  }
+
+  /** Returns the earliest element in a {@link DateTime} iterable. */
+  public static DateTime earliestOf(Iterable<DateTime> dates) {
+    checkArgument(!Iterables.isEmpty(dates));
+    return Ordering.<DateTime>natural().min(dates);
+  }
+
+  /** Returns the latest of a number of given {@link DateTime} instances. */
+  public static DateTime latestOf(DateTime first, DateTime... rest) {
+    return latestOf(Lists.asList(first, rest));
+  }
+
+  /** Returns the latest element in a {@link DateTime} iterable. */
+  public static DateTime latestOf(Iterable<DateTime> dates) {
+    checkArgument(!Iterables.isEmpty(dates));
+    return Ordering.<DateTime>natural().max(dates);
+  }
+
+  /** Returns whether the first {@link DateTime} is equal to or earlier than the second. */
+  public static boolean isBeforeOrAt(DateTime timeToCheck, DateTime timeToCompareTo) {
+    return !timeToCheck.isAfter(timeToCompareTo);
+  }
+
+  /** Returns whether the first {@link DateTime} is equal to or later than the second. */
+  public static boolean isAtOrAfter(DateTime timeToCheck, DateTime timeToCompareTo) {
+    return !timeToCheck.isBefore(timeToCompareTo);
+  }
+
+  /**
+   * Adds years to a date, in the {@code Duration} sense of semantic years. Use this instead of
+   * {@link DateTime#plusYears} to ensure that we never end up on February 29.
+   */
+  public static DateTime leapSafeAddYears(DateTime now, int years) {
+    checkArgument(years >= 0);
+    return years == 0 ? now : now.plusYears(1).plusYears(years - 1);
+  }
+
+  /**
+   * Subtracts years from a date, in the {@code Duration} sense of semantic years. Use this instead
+   * of {@link DateTime#minusYears} to ensure that we never end up on February 29.
+   */
+  public static DateTime leapSafeSubtractYears(DateTime now, int years) {
+    checkArgument(years >= 0);
+    return years == 0 ? now : now.minusYears(1).minusYears(years - 1);
+  }
+
+  /**
+   * Converts a Joda {@link DateTime} object to an equivalent java.time {@link ZonedDateTime}
+   * object.
+   */
+  public static ZonedDateTime toZonedDateTime(DateTime dateTime) {
+    java.time.Instant instant = java.time.Instant.ofEpochMilli(dateTime.getMillis());
+    return ZonedDateTime.ofInstant(instant, ZoneId.of(dateTime.getZone().getID()).normalized());
+  }
+
+  /**
+   * Converts a java.time {@link ZonedDateTime} object to an equivalent Joda {@link DateTime}
+   * object.
+   */
+  public static DateTime toJodaDateTime(ZonedDateTime zonedDateTime) {
+    return new DateTime(
+        zonedDateTime.toInstant().toEpochMilli(),
+        DateTimeZone.forTimeZone(TimeZone.getTimeZone(zonedDateTime.getZone())));
+  }
+}

common/src/main/java/google/registry/util/Sleeper.java

@@ -0,0 +1,45 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.util;
+
+import javax.annotation.concurrent.ThreadSafe;
+import org.joda.time.ReadableDuration;
+
+/**
+ * An object which accepts requests to put the current thread to sleep.
+ *
+ * @see SystemSleeper
+ * @see google.registry.testing.FakeSleeper
+ */
+@ThreadSafe
+public interface Sleeper {
+
+  /**
+   * Puts the current thread to sleep.
+   *
+   * @throws InterruptedException if this thread was interrupted
+   */
+  void sleep(ReadableDuration duration) throws InterruptedException;
+
+  /**
+   * Puts the current thread to sleep, ignoring interrupts.
+   *
+   * <p>If {@link InterruptedException} was caught, then {@code Thread.currentThread().interrupt()}
+   * will be called at the end of the {@code duration}.
+   *
+   * @see com.google.common.util.concurrent.Uninterruptibles#sleepUninterruptibly
+   */
+  void sleepUninterruptibly(ReadableDuration duration);
+}

common/src/main/java/google/registry/util/SystemClock.java

@@ -0,0 +1,37 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.util;
+
+import static org.joda.time.DateTimeZone.UTC;
+
+import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
+import org.joda.time.DateTime;
+
+/** Clock implementation that proxies to the real system clock. */
+@ThreadSafe
+public class SystemClock implements Clock {
+
+  private static final long serialVersionUID = 5165372013848947515L;
+
+  @Inject
+  public SystemClock() {}
+
+  /** Returns the current time. */
+  @Override
+  public DateTime nowUtc() {
+    return DateTime.now(UTC);
+  }
+}

common/src/main/java/google/registry/util/SystemSleeper.java

@@ -0,0 +1,46 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.util;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.util.concurrent.Uninterruptibles;
+import java.io.Serializable;
+import java.util.concurrent.TimeUnit;
+import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
+import org.joda.time.ReadableDuration;
+
+/** Implementation of {@link Sleeper} for production use. */
+@ThreadSafe
+public final class SystemSleeper implements Sleeper, Serializable {
+
+  private static final long serialVersionUID = 2003215961965322843L;
+
+  @Inject
+  public SystemSleeper() {}
+
+  @Override
+  public void sleep(ReadableDuration duration) throws InterruptedException {
+    checkArgument(duration.getMillis() >= 0);
+    Thread.sleep(duration.getMillis());
+  }
+
+  @Override
+  public void sleepUninterruptibly(ReadableDuration duration) {
+    checkArgument(duration.getMillis() >= 0);
+    Uninterruptibles.sleepUninterruptibly(duration.getMillis(), TimeUnit.MILLISECONDS);
+  }
+}

common/src/testing/java/google/registry/testing/FakeClock.java

@@ -0,0 +1,68 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.testing;
+
+import static google.registry.util.DateTimeUtils.START_OF_TIME;
+import static org.joda.time.DateTimeZone.UTC;
+import static org.joda.time.Duration.millis;
+
+import google.registry.util.Clock;
+import java.util.concurrent.atomic.AtomicLong;
+import javax.annotation.concurrent.ThreadSafe;
+import org.joda.time.DateTime;
+import org.joda.time.ReadableDuration;
+import org.joda.time.ReadableInstant;
+
+/** A mock clock for testing purposes that supports telling, setting, and advancing the time. */
+@ThreadSafe
+public final class FakeClock implements Clock {
+
+  private static final long serialVersionUID = 675054721685304599L;
+
+  // Clock isn't a thread synchronization primitive, but tests involving
+  // threads should see a consistent flow.
+  private final AtomicLong currentTimeMillis = new AtomicLong();
+
+  /** Creates a FakeClock that starts at START_OF_TIME. */
+  public FakeClock() {
+    this(START_OF_TIME);
+  }
+
+  /** Creates a FakeClock initialized to a specific time. */
+  public FakeClock(ReadableInstant startTime) {
+    setTo(startTime);
+  }
+
+  /** Returns the current time. */
+  @Override
+  public DateTime nowUtc() {
+    return new DateTime(currentTimeMillis.get(), UTC);
+  }
+
+  /** Advances clock by one millisecond. */
+  public void advanceOneMilli() {
+    advanceBy(millis(1));
+  }
+
+  /** Advances clock by some duration. */
+  public void advanceBy(ReadableDuration duration) {
+    currentTimeMillis.addAndGet(duration.getMillis());
+  }
+
+  /** Sets the time to the specified instant. */
+  public void setTo(ReadableInstant time) {
+    currentTimeMillis.set(time.getMillis());
+  }
+}

common/src/testing/java/google/registry/testing/FakeSleeper.java

@@ -0,0 +1,51 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.testing;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import google.registry.util.Sleeper;
+import java.io.Serializable;
+import javax.annotation.concurrent.ThreadSafe;
+import org.joda.time.ReadableDuration;
+
+/** Sleeper implementation for unit tests that advances {@link FakeClock} rather than sleep. */
+@ThreadSafe
+public final class FakeSleeper implements Sleeper, Serializable {
+
+  private static final long serialVersionUID = -8975804222581077291L;
+
+  private final FakeClock clock;
+
+  public FakeSleeper(FakeClock clock) {
+    this.clock = checkNotNull(clock, "clock");
+  }
+
+  @Override
+  public void sleep(ReadableDuration duration) throws InterruptedException {
+    checkArgument(duration.getMillis() >= 0);
+    if (Thread.interrupted()) {
+      throw new InterruptedException();
+    }
+    clock.advanceBy(duration);
+  }
+
+  @Override
+  public void sleepUninterruptibly(ReadableDuration duration) {
+    checkArgument(duration.getMillis() >= 0);
+    clock.advanceBy(duration);
+  }
+}

common/src/testing/java/google/registry/testing/SystemInfo.java

@@ -0,0 +1,64 @@
+// Copyright 2017 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.testing;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.flogger.FluentLogger;
+import java.io.IOException;
+import java.util.concurrent.ExecutionException;
+import javax.annotation.concurrent.ThreadSafe;
+
+/** Utility class for getting system information in tests. */
+@ThreadSafe
+public final class SystemInfo {
+
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  private static final LoadingCache<String, Boolean> hasCommandCache =
+      CacheBuilder.newBuilder()
+          .build(
+              new CacheLoader<String, Boolean>() {
+                @Override
+                public Boolean load(String cmd) throws InterruptedException {
+                  try {
+                    Process pid = Runtime.getRuntime().exec(cmd);
+                    pid.getOutputStream().close();
+                    pid.waitFor();
+                  } catch (IOException e) {
+                    logger.atWarning().withCause(e).log("%s command not available", cmd);
+                    return false;
+                  }
+                  return true;
+                }
+              });
+
+  /**
+   * Returns {@code true} if system command can be run from path.
+   *
+   * <p><b>Warning:</b> The command is actually run! So there could be side-effects. You might
+   * need to specify a version flag or something. Return code is ignored.
+   *
+   * <p>This result is a memoized. If multiple therads try to get the same result at once, the
+   * heavy lifting will only be performed by the first thread and the rest will wait.
+   *
+   * @throws ExecutionException
+   */
+  public static boolean hasCommand(String cmd) throws ExecutionException {
+    return hasCommandCache.get(cmd);
+  }
+
+}