Merge "Refactoring and tweaking TimeSparseArray"

core/java/android/util/TimeSparseArray.java

@@ -14,13 +14,11 @@
  * under the License.
  */
 
-package android.app.usage;
-
-import android.util.LongSparseArray;
-import android.util.Slog;
+package android.util;
 
 /**
  * An array that indexes by a long timestamp, representing milliseconds since the epoch.
+ * @param <E> The type of values this container maps to a timestamp.
  *
  * {@hide}
  */
@@ -29,53 +27,41 @@ public class TimeSparseArray<E> extends LongSparseArray<E> {
 
     private boolean mWtfReported;
 
-    public TimeSparseArray() {
-        super();
-    }
-
     /**
      * Finds the index of the first element whose timestamp is greater or equal to
      * the given time.
      *
      * @param time The timestamp for which to search the array.
-     * @return The index of the matched element, or -1 if no such match exists.
+     * @return The smallest {@code index} for which {@code (keyAt(index) >= timeStamp)} is
+     * {@code true}, or {@link #size() size} if no such {@code index} exists.
      */
     public int closestIndexOnOrAfter(long time) {
-        // This is essentially a binary search, except that if no match is found
-        // the closest index is returned.
         final int size = size();
+        int result = size;
         int lo = 0;
         int hi = size - 1;
-        int mid = -1;
-        long key = -1;
         while (lo <= hi) {
-            mid = lo + ((hi - lo) / 2);
-            key = keyAt(mid);
+            final int mid = lo + ((hi - lo) / 2);
+            final long key = keyAt(mid);
 
             if (time > key) {
                 lo = mid + 1;
             } else if (time < key) {
                 hi = mid - 1;
+                result = mid;
             } else {
                 return mid;
             }
         }
-
-        if (time < key) {
-            return mid;
-        } else if (time > key && lo < size) {
-            return lo;
-        } else {
-            return -1;
-        }
+        return result;
     }
 
     /**
      * {@inheritDoc}
      *
-     * <p> As this container is being used only to keep {@link android.util.AtomicFile files},
-     * there should not be any collisions. Reporting a {@link Slog#wtf(String, String)} in case that
-     * happens, as that will lead to one whole file being dropped.
+     * <p> This container can store only one value for each timestamp. And so ideally, the caller
+     * should ensure that there are no collisions. Reporting a {@link Slog#wtf(String, String)}
+     * if that happens, as that will lead to the previous value being overwritten.
      */
     @Override
     public void put(long key, E value) {
@@ -93,16 +79,13 @@ public class TimeSparseArray<E> extends LongSparseArray<E> {
      * the given time.
      *
      * @param time The timestamp for which to search the array.
-     * @return The index of the matched element, or -1 if no such match exists.
+     * @return The largest {@code index} for which {@code (keyAt(index) <= timeStamp)} is
+     * {@code true}, or -1 if no such {@code index} exists.
      */
     public int closestIndexOnOrBefore(long time) {
         final int index = closestIndexOnOrAfter(time);
-        if (index < 0) {
-            // Everything is larger, so we use the last element, or -1 if the list is empty.
-            return size() - 1;
-        }
 
-        if (keyAt(index) == time) {
+        if (index < size() && keyAt(index) == time) {
             return index;
         }
         return index - 1;

core/tests/coretests/src/android/util/TimeSparseArrayTest.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * 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 android.util;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/**
+ * Tests for {@link TimeSparseArray}.
+ * This class only tests subclass specific functionality. Tests for the super class
+ * {@link LongSparseArray} should be covered under {@link LongSparseArrayTest}.
+ */
+@SmallTest
+@RunWith(AndroidJUnit4.class)
+public class TimeSparseArrayTest {
+
+    @Test
+    public void closestIndexOnOrAfter() {
+        final TimeSparseArray<Object> timeSparseArray = new TimeSparseArray<>();
+
+        // Values don't matter for this test.
+        timeSparseArray.put(51, new Object());
+        timeSparseArray.put(10, new Object());
+        timeSparseArray.put(59, new Object());
+
+        assertThat(timeSparseArray.size()).isEqualTo(3);
+
+        // Testing any number arbitrarily smaller than 10.
+        assertThat(timeSparseArray.closestIndexOnOrAfter(-141213)).isEqualTo(0);
+        for (long time = -43; time <= 10; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrAfter(time)).isEqualTo(0);
+        }
+
+        for (long time = 11; time <= 51; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrAfter(time)).isEqualTo(1);
+        }
+
+        for (long time = 52; time <= 59; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrAfter(time)).isEqualTo(2);
+        }
+
+        for (long time = 60; time <= 102; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrAfter(time)).isEqualTo(3);
+        }
+        // Testing any number arbitrarily larger than 59.
+        assertThat(timeSparseArray.closestIndexOnOrAfter(15332)).isEqualTo(3);
+    }
+
+    @Test
+    public void closestIndexOnOrBefore() {
+        final TimeSparseArray<Object> timeSparseArray = new TimeSparseArray<>();
+
+        // Values don't matter for this test.
+        timeSparseArray.put(21, new Object());
+        timeSparseArray.put(4, new Object());
+        timeSparseArray.put(91, new Object());
+        timeSparseArray.put(39, new Object());
+
+        assertThat(timeSparseArray.size()).isEqualTo(4);
+
+        // Testing any number arbitrarily smaller than 4.
+        assertThat(timeSparseArray.closestIndexOnOrBefore(-1478133)).isEqualTo(-1);
+        for (long time = -42; time < 4; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrBefore(time)).isEqualTo(-1);
+        }
+
+        for (long time = 4; time < 21; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrBefore(time)).isEqualTo(0);
+        }
+
+        for (long time = 21; time < 39; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrBefore(time)).isEqualTo(1);
+        }
+
+        for (long time = 39; time < 91; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrBefore(time)).isEqualTo(2);
+        }
+
+        for (long time = 91; time < 109; time++) {
+            assertThat(timeSparseArray.closestIndexOnOrBefore(time)).isEqualTo(3);
+        }
+        // Testing any number arbitrarily larger than 91.
+        assertThat(timeSparseArray.closestIndexOnOrBefore(1980732)).isEqualTo(3);
+    }
+}

services/tests/servicestests/src/com/android/server/usage/UsageStatsDatabaseTest.java

@@ -24,7 +24,6 @@ import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertFalse;
 import static org.testng.Assert.assertTrue;
 
-import android.app.usage.TimeSparseArray;
 import android.app.usage.UsageEvents.Event;
 import android.app.usage.UsageStats;
 import android.app.usage.UsageStatsManager;
@@ -32,6 +31,7 @@ import android.content.Context;
 import android.content.res.Configuration;
 import android.test.suitebuilder.annotation.SmallTest;
 import android.util.AtomicFile;
+import android.util.TimeSparseArray;
 
 import androidx.test.InstrumentationRegistry;
 import androidx.test.runner.AndroidJUnit4;

services/usage/java/com/android/server/usage/UsageStatsDatabase.java

@@ -18,7 +18,6 @@ package com.android.server.usage;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
-import android.app.usage.TimeSparseArray;
 import android.app.usage.UsageEvents;
 import android.app.usage.UsageStats;
 import android.app.usage.UsageStatsManager;
@@ -29,6 +28,7 @@ import android.util.ArraySet;
 import android.util.AtomicFile;
 import android.util.Slog;
 import android.util.SparseArray;
+import android.util.TimeSparseArray;
 import android.util.TimeUtils;
 
 import com.android.internal.annotations.VisibleForTesting;

services/usage/java/com/android/server/usage/UserUsageStatsService.java

@@ -34,7 +34,6 @@ import android.annotation.Nullable;
 import android.app.usage.ConfigurationStats;
 import android.app.usage.EventList;
 import android.app.usage.EventStats;
-import android.app.usage.TimeSparseArray;
 import android.app.usage.UsageEvents;
 import android.app.usage.UsageEvents.Event;
 import android.app.usage.UsageStats;
@@ -50,6 +49,7 @@ import android.util.AtomicFile;
 import android.util.Slog;
 import android.util.SparseArrayMap;
 import android.util.SparseIntArray;
+import android.util.TimeSparseArray;
 
 import com.android.internal.util.ArrayUtils;
 import com.android.internal.util.CollectionUtils;