Add support for List.of(E...)
Also ensure invariant of no null elements is maintained in backport implementations.
Test: tools/test.py --no-internal -v *ListBackportJava9Test*
Change-Id: I5c77987b49db6ee8fc47d648a490143945efbeb0
diff --git a/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java b/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java
index f4905df..91e5902 100644
--- a/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java
+++ b/src/main/java/com/android/tools/r8/ir/desugar/BackportedMethodRewriter.java
@@ -851,17 +851,21 @@
factory.createProto(factory.intType, factory.intType, factory.intType, factory.intType);
addProvider(new MethodGenerator(clazz, method, proto, ObjectsMethods::new));
- // List of
+ // List<E> List.of(<args>) for 0 to 10 arguments
clazz = factory.listDescriptor;
method = factory.createString("of");
-
- // From 0 to 10 arguments.
ArrayList<DexType> parameters = new ArrayList<>();
for (int i = 0; i <= 10; i++) {
proto = factory.createProto(factory.listType, parameters);
addProvider(new MethodGenerator(clazz, method, proto, ListMethods::new));
parameters.add(factory.objectType);
}
+
+ // List<E> List.of(E...)
+ clazz = factory.listDescriptor;
+ method = factory.createString("of");
+ proto = factory.createProto(factory.listType, factory.objectArrayType);
+ addProvider(new MethodGenerator(clazz, method, proto, ListMethods::new, "ofVarargs"));
}
private void initializeJava11MethodProviders(DexItemFactory factory) {
diff --git a/src/main/java/com/android/tools/r8/ir/desugar/backports/ListMethods.java b/src/main/java/com/android/tools/r8/ir/desugar/backports/ListMethods.java
index 87f2a62..5499367 100644
--- a/src/main/java/com/android/tools/r8/ir/desugar/backports/ListMethods.java
+++ b/src/main/java/com/android/tools/r8/ir/desugar/backports/ListMethods.java
@@ -7,10 +7,12 @@
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.ir.synthetic.TemplateMethodCode;
import com.android.tools.r8.utils.InternalOptions;
-import java.util.Arrays;
+import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
+import java.util.Objects;
+@SuppressWarnings("unchecked")
public class ListMethods extends TemplateMethodCode {
public ListMethods(InternalOptions options, DexMethod method, String methodName) {
@@ -22,46 +24,64 @@
}
public static <E> List<E> of(E e0) {
- return Collections.singletonList(e0);
+ return Collections.singletonList(Objects.requireNonNull(e0));
}
public static <E> List<E> of(E e0, E e1) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1));
+ E[] elements = (E[]) new Object[] { e0, e1 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2));
+ E[] elements = (E[]) new Object[] { e0, e1, e2 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3, E e4) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3, e4));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3, e4 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3, E e4, E e5) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3, e4, e5));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3, e4, e5 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3, E e4, E e5, E e6) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3, e4, e5, e6));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3, e4, e5, e6 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3, E e4, E e5, E e6, E e7) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3, e4, e5, e6, e7));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3, e4, e5, e6, e7 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3, e4, e5, e6, e7, e8));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3, e4, e5, e6, e7, e8 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3, e4, e5, e6, e7, e8, e9));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3, e4, e5, e6, e7, e8, e9 };
+ return List.of(elements);
}
public static <E> List<E> of(E e0, E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10) {
- return Collections.unmodifiableList(Arrays.asList(e0, e1, e2, e3, e4, e5, e6, e7, e8, e9, e10));
+ E[] elements = (E[]) new Object[] { e0, e1, e2, e3, e4, e5, e6, e7, e8, e9, e10 };
+ return List.of(elements);
+ }
+
+ public static <E> List<E> ofVarargs(E[] elements) {
+ ArrayList<E> list = new ArrayList<>(elements.length);
+ for (E element : elements) {
+ list.add(Objects.requireNonNull(element));
+ }
+ return Collections.unmodifiableList(list);
}
}
diff --git a/src/test/examplesJava9/backport/ListBackportJava9Main.java b/src/test/examplesJava9/backport/ListBackportJava9Main.java
index 9ad147f..4c8ae88 100644
--- a/src/test/examplesJava9/backport/ListBackportJava9Main.java
+++ b/src/test/examplesJava9/backport/ListBackportJava9Main.java
@@ -8,59 +8,163 @@
public class ListBackportJava9Main {
- public static void main(String[] args) throws Exception {
+ public static void main(String[] args) {
testOf0();
testOf1();
testOf2();
testOf10();
+ testOfVarargs();
}
private static void testOf0() {
List<Object> ofObject = List.of();
+ assertEquals(0, ofObject.size());
+ assertMutationNotAllowed(ofObject);
+
List<Integer> ofInteger = List.of();
- assertTrue(ofObject instanceof List);
- assertTrue(ofObject.size() == 0);
- assertTrue(ofInteger instanceof List);
- assertTrue(ofInteger.size() == 0);
+ assertEquals(0, ofInteger.size());
+ assertMutationNotAllowed(ofObject);
}
private static void testOf1() {
- List<Object> ofObject = List.of(new Object());
+ Object anObject = new Object();
+ List<Object> ofObject = List.of(anObject);
+ assertEquals(1, ofObject.size());
+ assertSame(anObject, ofObject.get(0));
+ assertMutationNotAllowed(ofObject);
+
List<Integer> ofInteger = List.of(1);
- assertTrue(ofObject instanceof List);
- assertTrue(ofObject.size() == 1);
- assertTrue(ofInteger instanceof List);
- assertTrue(ofInteger.size() == 1);
+ assertEquals(1, ofInteger.size());
+ assertEquals(1, ofInteger.get(0));
+
+ try {
+ List.of((Object) null);
+ throw new AssertionError();
+ } catch (NullPointerException expected) {
+ }
}
private static void testOf2() {
- List<Object> ofObject = List.of(new Object(), new Object());
+ Object anObject0 = new Object();
+ Object anObject1 = new Object();
+ List<Object> ofObject = List.of(anObject0, anObject1);
+ assertEquals(2, ofObject.size());
+ assertSame(anObject0, ofObject.get(0));
+ assertSame(anObject1, ofObject.get(1));
+ assertMutationNotAllowed(ofObject);
+
List<Integer> ofInteger = List.of(1, 2);
- List<Object> ofMixed = List.of(new Object(), 1);
- assertTrue(ofObject instanceof List);
- assertTrue(ofObject.size() == 2);
- assertTrue(ofInteger instanceof List);
- assertTrue(ofInteger.size() == 2);
- assertTrue(ofMixed instanceof List);
- assertTrue(ofMixed.size() == 2);
+ assertEquals(2, ofInteger.size());
+ assertEquals(1, ofInteger.get(0));
+ assertEquals(2, ofInteger.get(1));
+
+ List<Object> ofMixed = List.of(anObject0, 1);
+ assertEquals(2, ofMixed.size());
+ assertSame(anObject0, ofMixed.get(0));
+ assertEquals(1, ofMixed.get(1));
+ assertMutationNotAllowed(ofMixed);
+
+ try {
+ List.of(1, null);
+ throw new AssertionError();
+ } catch (NullPointerException expected) {
+ }
}
private static void testOf10() {
- Object e = new Object();
- List<Object> ofObject = List.of(e, e, e, e, e, e, e, e, e, e);
+ Object anObject0 = new Object();
+ Object anObject6 = new Object();
+ Object anObject9 = new Object();
+ List<Object> ofObject =
+ List.of(anObject0, new Object(), new Object(), new Object(), new Object(), new Object(),
+ anObject6, new Object(), new Object(), anObject9);
+ assertEquals(10, ofObject.size());
+ assertSame(anObject0, ofObject.get(0));
+ assertSame(anObject6, ofObject.get(6));
+ assertSame(anObject9, ofObject.get(9));
+ assertMutationNotAllowed(ofObject);
+
List<Integer> ofInteger = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
- List<Object> ofMixed = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, e);
- assertTrue(ofObject instanceof List);
- assertTrue(ofObject.size() == 10);
- assertTrue(ofInteger instanceof List);
- assertTrue(ofInteger.size() == 10);
- assertTrue(ofMixed instanceof List);
- assertTrue(ofMixed.size() == 10);
+ assertEquals(10, ofInteger.size());
+ assertEquals(0, ofInteger.get(0));
+ assertEquals(6, ofInteger.get(6));
+ assertEquals(9, ofInteger.get(9));
+
+ List<Object> ofMixed = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, anObject9);
+ assertEquals(10, ofMixed.size());
+ assertEquals(0, ofMixed.get(0));
+ assertEquals(6, ofMixed.get(6));
+ assertSame(anObject9, ofMixed.get(9));
+ assertMutationNotAllowed(ofMixed);
+
+ try {
+ List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, null);
+ throw new AssertionError();
+ } catch (NullPointerException expected) {
+ }
}
- private static void assertTrue(boolean value) {
- if (!value) {
- throw new AssertionError("Expected <true> but was <false>");
+ private static void testOfVarargs() {
+ Object anObject0 = new Object();
+ Object anObject6 = new Object();
+ Object anObject10 = new Object();
+ List<Object> ofObject =
+ List.of(anObject0, new Object(), new Object(), new Object(), new Object(), new Object(),
+ anObject6, new Object(), new Object(), new Object(), anObject10);
+ assertEquals(11, ofObject.size());
+ assertSame(anObject0, ofObject.get(0));
+ assertSame(anObject6, ofObject.get(6));
+ assertSame(anObject10, ofObject.get(10));
+ assertMutationNotAllowed(ofObject);
+
+ List<Integer> ofInteger = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ assertEquals(11, ofInteger.size());
+ assertEquals(0, ofInteger.get(0));
+ assertEquals(6, ofInteger.get(6));
+ assertEquals(10, ofInteger.get(10));
+
+ List<Object> ofMixed = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, anObject10);
+ assertEquals(11, ofMixed.size());
+ assertEquals(0, ofMixed.get(0));
+ assertEquals(6, ofMixed.get(6));
+ assertSame(anObject10, ofMixed.get(10));
+ assertMutationNotAllowed(ofMixed);
+
+ // Ensure the supplied mutable array is not used directly since it is mutable.
+ Object[] mutableArray = { anObject0 };
+ List<Object> ofMutableArray = List.of(mutableArray);
+ mutableArray[0] = anObject10;
+ assertSame(anObject0, ofMutableArray.get(0));
+
+ try {
+ List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, null);
+ throw new AssertionError();
+ } catch (NullPointerException expected) {
+ }
+ }
+
+ private static void assertMutationNotAllowed(List<Object> ofObject) {
+ try {
+ ofObject.add(new Object());
+ throw new AssertionError();
+ } catch (UnsupportedOperationException expected) {
+ }
+ try {
+ ofObject.set(0, new Object());
+ throw new AssertionError();
+ } catch (UnsupportedOperationException expected) {
+ }
+ }
+
+ private static void assertSame(Object expected, Object actual) {
+ if (expected != actual) {
+ throw new AssertionError("Expected <" + expected + "> but was <" + actual + ">");
+ }
+ }
+
+ private static void assertEquals(Object expected, Object actual) {
+ if (expected != actual && !expected.equals(actual)) {
+ throw new AssertionError("Expected <" + expected + "> but was <" + actual + ">");
}
}
}
