Merge "Guarding collisions in TimeSparseArray" into pi-dev

core/java/android/app/usage/TimeSparseArray.java

@@ -17,6 +17,7 @@
 package android.app.usage;
 
 import android.util.LongSparseArray;
+import android.util.Slog;
 
 /**
  * An array that indexes by a long timestamp, representing milliseconds since the epoch.
@@ -24,6 +25,8 @@ import android.util.LongSparseArray;
  * {@hide}
  */
 public class TimeSparseArray<E> extends LongSparseArray<E> {
+    private static final String TAG = TimeSparseArray.class.getSimpleName();
+
     public TimeSparseArray() {
         super();
     }
@@ -69,6 +72,25 @@ public class TimeSparseArray<E> extends LongSparseArray<E> {
         }
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * Overridden to ensure no collisions. The key (time in milliseconds) is incremented till an
+     * empty place is found.
+     */
+    @Override
+    public void put(long key, E value) {
+        final long origKey = key;
+        while (indexOfKey(key) >= 0) {
+            key++;
+        }
+        if (origKey != key) {
+            Slog.w(TAG, "Value " + value + " supposed to be inserted at " + origKey
+                    + " displaced to " + key);
+        }
+        super.put(key, value);
+    }
+
     /**
      * Finds the index of the first element whose timestamp is less than or equal to
      * the given time.

core/tests/coretests/src/android/app/usage/TimeSparseArrayTest.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2018 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.app.usage;
+
+import static org.junit.Assert.assertTrue;
+
+import android.os.SystemClock;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class TimeSparseArrayTest {
+    @Test
+    public void testDuplicateKeysNotDropped() {
+        final TimeSparseArray<Integer> testTimeSparseArray = new TimeSparseArray<>();
+        final long key = SystemClock.elapsedRealtime();
+        for (int i = 0; i < 5; i++) {
+            testTimeSparseArray.put(key, i);
+        }
+        for (int i = 0; i < 5; i++) {
+            final int valueIndex = testTimeSparseArray.indexOfValue(i);
+            assertTrue("Value " + i + " not found; intended key: " + key , valueIndex >= 0);
+            final long keyForValue = testTimeSparseArray.keyAt(valueIndex);
+            assertTrue("Value " + i + " stored too far (at " + keyForValue + ") from intended key "
+                    + key, Math.abs(keyForValue - key) < 100);
+        }
+    }
+}