Firestore: use Integer.compare() to compare integers instead of the bespoke Util.compareIntegers() method.

The `Util.compareIntegers()` method was originally added because it
required minSdkVersion of 19 or greater which, at the time, was not the
case. However, minSdkVersion has been 21 for some time now (and is
increasing to 23 in the foreseeable future) so there is no longer any
need for the bespoke implementation.

Author: dconeybe

firebase-firestore/CHANGELOG.md

@@ -2,6 +2,9 @@
 * [fixed] Further improved performance of UTF-8 string ordering logic,
   which had degraded in v25.1.2 and received some improvements in v25.1.3.
   [#7053](//github.com/firebase/firebase-android-sdk/issues/7053)
+* [changed] Use `Integer.compare()` (which was added in Android API 19) to compare integers instead
+  of Firestore's bespoke implementation, since minSdkVersion has been greater than 19 for some time.
+  [#NNNN](//github.com/firebase/firebase-android-sdk/pull/NNNN)
 
 
 # 25.1.4

firebase-firestore/src/main/java/com/google/firebase/firestore/core/View.java

@@ -17,7 +17,6 @@
 import static com.google.firebase.firestore.core.Query.LimitType.LIMIT_TO_FIRST;
 import static com.google.firebase.firestore.core.Query.LimitType.LIMIT_TO_LAST;
 import static com.google.firebase.firestore.util.Assert.hardAssert;
-import static com.google.firebase.firestore.util.Util.compareIntegers;
 
 import androidx.annotation.Nullable;
 import com.google.firebase.database.collection.ImmutableSortedMap;
@@ -301,7 +300,7 @@ public ViewChange applyChanges(
     Collections.sort(
         viewChanges,
         (DocumentViewChange o1, DocumentViewChange o2) -> {
-          int typeComp = compareIntegers(View.changeTypeOrder(o1), View.changeTypeOrder(o2));
+          int typeComp = Integer.compare(View.changeTypeOrder(o1), View.changeTypeOrder(o2));
           if (typeComp != 0) {
             return typeComp;
           }

firebase-firestore/src/main/java/com/google/firebase/firestore/local/DocumentReference.java

@@ -14,8 +14,6 @@
 
 package com.google.firebase.firestore.local;
 
-import static com.google.firebase.firestore.util.Util.compareIntegers;
-
 import com.google.firebase.firestore.model.DocumentKey;
 import java.util.Comparator;
 
@@ -60,12 +58,12 @@ int getId() {
           return keyComp;
         }
 
-        return compareIntegers(o1.targetOrBatchId, o2.targetOrBatchId);
+        return Integer.compare(o1.targetOrBatchId, o2.targetOrBatchId);
       };
 
   static final Comparator<DocumentReference> BY_TARGET =
       (o1, o2) -> {
-        int targetComp = compareIntegers(o1.targetOrBatchId, o2.targetOrBatchId);
+        int targetComp = Integer.compare(o1.targetOrBatchId, o2.targetOrBatchId);
 
         if (targetComp != 0) {
           return targetComp;

firebase-firestore/src/main/java/com/google/firebase/firestore/local/SQLiteMutationQueue.java

@@ -324,7 +324,7 @@ public List<MutationBatch> getAllMutationBatchesAffectingDocumentKeys(
       Collections.sort(
           result,
           (MutationBatch lhs, MutationBatch rhs) ->
-              Util.compareIntegers(lhs.getBatchId(), rhs.getBatchId()));
+              Integer.compare(lhs.getBatchId(), rhs.getBatchId()));
     }
     return result;
   }

firebase-firestore/src/main/java/com/google/firebase/firestore/model/BasePath.java

@@ -100,7 +100,7 @@ public int compareTo(@NonNull B o) {
       }
       i++;
     }
-    return Util.compareIntegers(myLength, theirLength);
+    return Integer.compare(myLength, theirLength);
   }
 
   private static int compareSegments(String lhs, String rhs) {

firebase-firestore/src/main/java/com/google/firebase/firestore/model/Values.java

@@ -214,7 +214,7 @@ public static int compare(Value left, Value right) {
     int rightType = typeOrder(right);
 
     if (leftType != rightType) {
-      return Util.compareIntegers(leftType, rightType);
+      return Integer.compare(leftType, rightType);
     }
 
     switch (leftType) {
@@ -305,7 +305,7 @@ private static int compareTimestamps(Timestamp left, Timestamp right) {
     if (cmp != 0) {
       return cmp;
     }
-    return Util.compareIntegers(left.getNanos(), right.getNanos());
+    return Integer.compare(left.getNanos(), right.getNanos());
   }
 
   private static int compareReferences(String leftPath, String rightPath) {
@@ -319,7 +319,7 @@ private static int compareReferences(String leftPath, String rightPath) {
         return cmp;
       }
     }
-    return Util.compareIntegers(leftSegments.length, rightSegments.length);
+    return Integer.compare(leftSegments.length, rightSegments.length);
   }
 
   private static int compareGeoPoints(LatLng left, LatLng right) {
@@ -338,7 +338,7 @@ private static int compareArrays(ArrayValue left, ArrayValue right) {
         return cmp;
       }
     }
-    return Util.compareIntegers(left.getValuesCount(), right.getValuesCount());
+    return Integer.compare(left.getValuesCount(), right.getValuesCount());
   }
 
   private static int compareMaps(MapValue left, MapValue right) {
@@ -372,7 +372,7 @@ private static int compareVectors(MapValue left, MapValue right) {
     ArrayValue rightArrayValue = rightMap.get(Values.VECTOR_MAP_VECTORS_KEY).getArrayValue();
 
     int lengthCompare =
-        Util.compareIntegers(leftArrayValue.getValuesCount(), rightArrayValue.getValuesCount());
+        Integer.compare(leftArrayValue.getValuesCount(), rightArrayValue.getValuesCount());
     if (lengthCompare != 0) {
       return lengthCompare;
     }

firebase-firestore/src/main/java/com/google/firebase/firestore/util/Util.java

@@ -73,20 +73,6 @@ public static int compareBooleans(boolean b1, boolean b2) {
     }
   }
 
-  /**
-   * Utility function to compare integers. Note that we can't use Integer.compare because it's only
-   * available after Android 19.
-   */
-  public static int compareIntegers(int i1, int i2) {
-    if (i1 < i2) {
-      return -1;
-    } else if (i1 > i2) {
-      return 1;
-    } else {
-      return 0;
-    }
-  }
-
   /** Compare strings in UTF-8 encoded byte order */
   public static int compareUtf8Strings(String left, String right) {
     // noinspection StringEquality
@@ -119,7 +105,7 @@ public static int compareUtf8Strings(String left, String right) {
       final char rightChar = right.charAt(i);
       if (leftChar != rightChar) {
         return (isSurrogate(leftChar) == isSurrogate(rightChar))
-            ? Util.compareIntegers(leftChar, rightChar)
+            ? Integer.compare(leftChar, rightChar)
             : isSurrogate(leftChar) ? 1 : -1;
       }
     }
@@ -274,7 +260,7 @@ public static int compareByteArrays(byte[] left, byte[] right) {
       }
       // Byte values are equal, continue with comparison
     }
-    return Util.compareIntegers(left.length, right.length);
+    return Integer.compare(left.length, right.length);
   }
 
   public static int compareByteStrings(ByteString left, ByteString right) {
@@ -290,7 +276,7 @@ public static int compareByteStrings(ByteString left, ByteString right) {
       }
       // Byte values are equal, continue with comparison
     }
-    return Util.compareIntegers(left.size(), right.size());
+    return Integer.compare(left.size(), right.size());
   }
 
   public static StringBuilder repeatSequence(