add a comparator for LogMaker

Tests need to be able to compare partial log structures.

Bug: 34705522
Test: runtest --path frameworks/base/core/tests/coretests/src/android/metrics
Change-Id: I4e26e43f5f5ea3fbba5a2a2a9563982c7260671b

api/system-current.txt

@@ -26158,6 +26158,7 @@ package android.metrics {
     method public long getTimestamp();
     method public int getType();
     method public boolean isLongCounterBucket();
+    method public boolean isSubsetOf(android.metrics.LogMaker);
     method public boolean isValidValue(java.lang.Object);
     method public java.lang.Object[] serialize();
     method public android.metrics.LogMaker setCategory(int);

core/java/android/metrics/LogMaker.java

@@ -240,6 +240,9 @@ public class LogMaker {
         return out;
     }
 
+    /**
+     * Reconstitute an object from the output of {@link #serialize()}.
+     */
     public void deserialize(Object[] items) {
         int i = 0;
         while (i < items.length) {
@@ -252,4 +255,22 @@ public class LogMaker {
             }
         }
     }
+
+    /**
+     * @param that the object to compare to.
+     * @return true if values in that equal values in this, for tags that exist in this.
+     */
+    public boolean isSubsetOf(LogMaker that) {
+        if (that == null) {
+            return false;
+        }
+        for (int i = 0; i < entries.size(); i++) {
+            int key = this.entries.keyAt(i);
+            Object thisValue = this.entries.valueAt(i);
+            Object thatValue = that.entries.get(key);
+            if ((thisValue == null && thatValue != null) || !thisValue.equals(thatValue))
+                return false;
+        }
+        return true;
+    }
 }

core/tests/coretests/src/android/metrics/LogMakerTest.java

@@ -132,4 +132,78 @@ public class LogMakerTest extends TestCase {
         assertTrue(badBuilder.serialize().length < LogMaker.MAX_SERIALIZED_SIZE);
     }
 
+    public void testIdentityEquality() {
+        LogMaker a = new LogMaker(0);
+        a.addTaggedData(1, "onetwothree");
+        a.addTaggedData(2, 123);
+        a.addTaggedData(3, 123L);
+
+        assertTrue("objects should be equal to themselves", a.isSubsetOf(a));
+    }
+
+    public void testExactEquality() {
+        LogMaker a = new LogMaker(0);
+        a.addTaggedData(1, "onetwothree");
+        a.addTaggedData(2, 123);
+        a.addTaggedData(3, 123L);
+        LogMaker b = new LogMaker(0);
+        b.addTaggedData(1, "onetwothree");
+        b.addTaggedData(2, 123);
+        b.addTaggedData(3, 123L);
+
+        assertTrue("deep equality should be true", a.isSubsetOf(b));
+        assertTrue("deep equality shoudl be true", b.isSubsetOf(a));
+    }
+
+    public void testSubsetEquality() {
+        LogMaker a = new LogMaker(0);
+        a.addTaggedData(1, "onetwothree");
+        a.addTaggedData(2, 123);
+        LogMaker b = new LogMaker(0);
+        b.addTaggedData(1, "onetwothree");
+        b.addTaggedData(2, 123);
+        b.addTaggedData(3, 123L);
+
+        assertTrue("a is a strict subset of b", a.isSubsetOf(b));
+        assertTrue("b is not a strict subset of a", !b.isSubsetOf(a));
+    }
+
+    public void testInequality() {
+        LogMaker a = new LogMaker(0);
+        a.addTaggedData(1, "onetwofour");
+        a.addTaggedData(2, 1234);
+        LogMaker b = new LogMaker(0);
+        b.addTaggedData(1, "onetwothree");
+        b.addTaggedData(2, 123);
+        b.addTaggedData(3, 123L);
+
+        assertTrue("a is not a subset of b", !a.isSubsetOf(b));
+        assertTrue("b is not a subset of a", !b.isSubsetOf(a));
+    }
+
+    public void testWildcardEquality() {
+        LogMaker empty = new LogMaker(0);
+        empty.clearTaggedData(MetricsEvent.RESERVED_FOR_LOGBUILDER_CATEGORY);  //dirty trick
+        LogMaker b = new LogMaker(0);
+        b.addTaggedData(1, "onetwothree");
+        b.addTaggedData(2, 123);
+        b.addTaggedData(3, 123L);
+
+        assertTrue("empty builder is a subset of anything", empty.isSubsetOf(b));
+    }
+
+    public void testNullEquality() {
+        LogMaker a = new LogMaker(0);
+        a.addTaggedData(1, "onetwofour");
+        a.addTaggedData(2, 1234);
+
+        assertTrue("a is not a subset of null", !a.isSubsetOf(null));
+    }
+
+    public void testMajorCategory() {
+        LogMaker a = new LogMaker(1);
+        LogMaker b = new LogMaker(2);
+        assertFalse(a.isSubsetOf(b));
+        assertFalse(b.isSubsetOf(a));
+    }
 }