Codegen for parcelable/dataclass boilerplate

This is the initial implementation of the `codegen` cli utility
for in-place java boilerplate generation

See DataClass and SampleDataClass for documentation/guide/examples.

See tools/codegen/ for implementation and tests/Codegen/ for tests.

Bug: 64221737
Test: . frameworks/base/tests/Codegen/runTest.sh
Change-Id: I75177cb770f1beabc87dbae9e77ce4b93ca08e7f

1 files changed, 219 insertions, 0 deletions

diff --git a/tests/Codegen/src/com/android/codegentest/SampleDataClassTest.java b/tests/Codegen/src/com/android/codegentest/SampleDataClassTest.java
new file mode 100644
index 000000000000..71e85ab00eab
--- /dev/null
+++ b/tests/Codegen/src/com/android/codegentest/SampleDataClassTest.java
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2019 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 com.android.codegentest;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.instanceOf;
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertThat;
+
+import android.net.LinkAddress;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.Arrays;
+import java.util.Date;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Tests {@link SampleDataClass} after it's augmented with dataclass codegen.
+ *
+ * Use {@code $ . runTest.sh} to run.
+ */
+@RunWith(AndroidJUnit4.class)
+public class SampleDataClassTest {
+
+    private SampleDataClass mSpecimen = newBuilder().build();
+
+    private static SampleDataClass.Builder newBuilder() {
+        return newIncompleteBuilder()
+                .setNum(42)
+                .setNum2(42)
+                .setNum4(42)
+                .setName4("foobar")
+                .setLinkAddresses5();
+    }
+
+    private static SampleDataClass.Builder newIncompleteBuilder() {
+        return new SampleDataClass.Builder()
+                .markActive()
+                .setName("some parcelable")
+                .setFlags(SampleDataClass.FLAG_MANUAL_REQUEST);
+    }
+
+    @Test
+    public void testParcelling_producesEqualInstance() {
+        SampleDataClass copy = parcelAndUnparcel(mSpecimen, SampleDataClass.CREATOR);
+        assertEquals(mSpecimen, copy);
+        assertEquals(mSpecimen.hashCode(), copy.hashCode());
+    }
+
+    @Test
+    public void testParcelling_producesInstanceWithEqualFields() {
+        SampleDataClass copy = parcelAndUnparcel(mSpecimen, SampleDataClass.CREATOR);
+        copy.forEachField((self, copyFieldName, copyFieldValue) -> {
+            mSpecimen.forEachField((self2, specimenFieldName, specimenFieldValue) -> {
+                if (copyFieldName.equals(specimenFieldName)
+                        && !copyFieldName.equals("pattern")
+                        && (specimenFieldValue == null
+                                || !specimenFieldValue.getClass().isArray())) {
+                    assertEquals("Mismatched field values for " + copyFieldName,
+                            specimenFieldValue, copyFieldValue);
+                }
+            });
+        });
+    }
+
+    @Test
+    public void testCustomParcelling_instanceIsCached() {
+        parcelAndUnparcel(mSpecimen, SampleDataClass.CREATOR);
+        parcelAndUnparcel(mSpecimen, SampleDataClass.CREATOR);
+        assertEquals(1, DateParcelling.sInstanceCount.get());
+    }
+
+    @Test
+    public void testDefaultFieldValue_isPropagated() {
+        assertEquals(new Date(42 * 42), mSpecimen.getDate());
+    }
+
+    @Test
+    public void testForEachField_avoidsBoxing() {
+        AtomicInteger intFieldCount = new AtomicInteger(0);
+        mSpecimen.forEachField(
+                (self, name, intValue) -> intFieldCount.getAndIncrement(),
+                (self, name, objectValue) -> {
+                    if (objectValue != null) {
+                        assertThat("Boxed field " + name,
+                                objectValue, not(instanceOf(Integer.class)));
+                    }
+                });
+        assertThat(intFieldCount.get(), greaterThanOrEqualTo(1));
+    }
+
+    @Test
+    public void testToString_containsEachField() {
+        String toString = mSpecimen.toString();
+
+        mSpecimen.forEachField((self, name, value) -> {
+            assertThat(toString, containsString(name));
+            if (value instanceof Integer) {
+                // Could be flags, their special toString tested separately
+            } else if (value instanceof Object[]) {
+                assertThat(toString, containsString(Arrays.toString((Object[]) value)));
+            } else if (value != null && value.getClass().isArray()) {
+                // Primitive array, uses multiple specialized Arrays.toString overloads
+            } else {
+                assertThat(toString, containsString("" + value));
+            }
+        });
+    }
+
+    @Test
+    public void testBuilder_propagatesValuesToInstance() {
+        assertEquals(43, newBuilder().setNum(43).build().getNum());
+    }
+
+    @Test
+    public void testPluralFields_canHaveCustomSingularBuilderName() {
+        newBuilder().addLinkAddress(new LinkAddress("127.0.0.1/24"));
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testBuilder_usableOnlyOnce() {
+        SampleDataClass.Builder builder = newBuilder();
+        builder.build();
+        builder.build();
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testBuilder_throwsWhenRequiredFieldMissing() {
+        newIncompleteBuilder().build();
+    }
+
+    @Test
+    public void testIntDefs_haveCorrectToString() {
+        int flagsAsInt = SampleDataClass.FLAG_MANUAL_REQUEST
+                | SampleDataClass.FLAG_COMPATIBILITY_MODE_REQUEST;
+        String flagsAsString = SampleDataClass.requestFlagsToString(flagsAsInt);
+
+        assertThat(flagsAsString, containsString("MANUAL_REQUEST"));
+        assertThat(flagsAsString, containsString("COMPATIBILITY_MODE_REQUEST"));
+        assertThat(flagsAsString, not(containsString("1")));
+        assertThat(flagsAsString, not(containsString("" + flagsAsInt)));
+
+        String dataclassToString = newBuilder()
+                .setFlags(flagsAsInt)
+                .setState(SampleDataClass.STATE_UNDEFINED)
+                .build()
+                .toString();
+        assertThat(dataclassToString, containsString(flagsAsString));
+        assertThat(dataclassToString, containsString("UNDEFINED"));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testFlags_getValidated() {
+        newBuilder().setFlags(12345).build();
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testIntEnums_getValidated() {
+        newBuilder().setState(12345).build();
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testStringEnums_getValidated() {
+        newBuilder().setStateName("foo").build();
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testCustomValidation_isTriggered() {
+        newBuilder().setNum2(-1).setNum4(1).build();
+    }
+
+    @Test
+    public void testLazyInit_isLazilyCalledOnce() {
+        assertNull(mSpecimen.mTmpStorage);
+
+        int[] tmpStorage = mSpecimen.getTmpStorage();
+        assertNotNull(tmpStorage);
+        assertSame(tmpStorage, mSpecimen.mTmpStorage);
+
+        int[] tmpStorageAgain = mSpecimen.getTmpStorage();
+        assertSame(tmpStorage, tmpStorageAgain);
+    }
+
+    private static <T extends Parcelable> T parcelAndUnparcel(
+            T original, Parcelable.Creator<T> creator) {
+        Parcel p = Parcel.obtain();
+        try {
+            original.writeToParcel(p, 0);
+            p.setDataPosition(0);
+            return creator.createFromParcel(p);
+        } finally {
+            p.recycle();
+        }
+    }
+}