[view-compiler] Add layout validation

Layout validation walks over a layout resource and verifies that the layout only
uses features the layout compiler supports.

Currently this means we reject layouts that use any of the following tags:
  * include
  * fragment
  * merge
  * view

In the future, we will extend the layout compiler to handle these, but for now
we want to be liberal in what we reject.

Bug: 111895153
Test: atest view-compiler-tests
Change-Id: I8dca30c035a83b6763497a36fc60c68438fa1b0c

1 files changed, 163 insertions, 0 deletions

diff --git a/startop/view_compiler/layout_validation_test.cc b/startop/view_compiler/layout_validation_test.cc
new file mode 100644
index 000000000000..b74cdae8d725
--- /dev/null
+++ b/startop/view_compiler/layout_validation_test.cc
@@ -0,0 +1,163 @@
+/*
+ * 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.
+ */
+#include "tinyxml_layout_parser.h"
+
+#include "gtest/gtest.h"
+
+using startop::CanCompileLayout;
+using std::string;
+
+namespace {
+void ValidateXmlText(const string& xml, bool expected) {
+  tinyxml2::XMLDocument doc;
+  doc.Parse(xml.c_str());
+  EXPECT_EQ(CanCompileLayout(doc), expected);
+}
+}  // namespace
+
+TEST(LayoutValidationTest, SingleButtonLayout) {
+  const string xml = R"(<?xml version="1.0" encoding="utf-8"?>
+<Button xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:text="Hello, World!">
+
+</Button>)";
+  ValidateXmlText(xml, /*expected=*/true);
+}
+
+TEST(LayoutValidationTest, SmallConstraintLayout) {
+  const string xml = R"(<?xml version="1.0" encoding="utf-8"?>
+<android.support.constraint.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <Button
+        android:id="@+id/button6"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginEnd="16dp"
+        android:layout_marginBottom="16dp"
+        android:text="Button"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent" />
+
+    <Button
+        android:id="@+id/button7"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="16dp"
+        android:text="Button2"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toStartOf="@+id/button6" />
+
+    <Button
+        android:id="@+id/button8"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="16dp"
+        android:text="Button1"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toStartOf="@+id/button7" />
+</android.support.constraint.ConstraintLayout>)";
+  ValidateXmlText(xml, /*expected=*/true);
+}
+
+TEST(LayoutValidationTest, MergeNode) {
+  const string xml = R"(<?xml version="1.0" encoding="utf-8"?>
+<merge xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <TextView
+        android:id="@+id/textView3"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="TextView" />
+
+    <Button
+        android:id="@+id/button9"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Button" />
+</merge>)";
+  ValidateXmlText(xml, /*expected=*/false);
+}
+
+TEST(LayoutValidationTest, IncludeLayout) {
+  const string xml = R"(<?xml version="1.0" encoding="utf-8"?>
+<android.support.constraint.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <include
+        layout="@layout/single_button_layout"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+</android.support.constraint.ConstraintLayout>)";
+  ValidateXmlText(xml, /*expected=*/false);
+}
+
+TEST(LayoutValidationTest, ViewNode) {
+  const string xml = R"(<?xml version="1.0" encoding="utf-8"?>
+<android.support.constraint.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <view
+        class="android.support.design.button.MaterialButton"
+        id="@+id/view"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+</android.support.constraint.ConstraintLayout>)";
+  ValidateXmlText(xml, /*expected=*/false);
+}
+
+TEST(LayoutValidationTest, FragmentNode) {
+  // This test case is from https://developer.android.com/guide/components/fragments
+  const string xml = R"(<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="horizontal"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+    <fragment android:name="com.example.news.ArticleListFragment"
+            android:id="@+id/list"
+            android:layout_weight="1"
+            android:layout_width="0dp"
+            android:layout_height="match_parent" />
+    <fragment android:name="com.example.news.ArticleReaderFragment"
+            android:id="@+id/viewer"
+            android:layout_weight="2"
+            android:layout_width="0dp"
+            android:layout_height="match_parent" />
+</LinearLayout>)";
+  ValidateXmlText(xml, /*expected=*/false);
+}