[wpiutil] Add reflection based cleanup helper (#4919)

Co-authored-by: Starlight220 <53231611+Starlight220@users.noreply.github.com>

wpiutil/src/test/java/edu/wpi/first/util/cleanup/CleanupPoolTest.java

@@ -0,0 +1,154 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.util.cleanup;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class CleanupPoolTest {
+  static class AutoCloseableObject implements AutoCloseable {
+    public boolean m_closed;
+
+    @Override
+    public void close() {
+      m_closed = true;
+    }
+  }
+
+  static class AutoCloseableObjectWithCallback implements AutoCloseable {
+    private final Runnable m_cb;
+
+    AutoCloseableObjectWithCallback(Runnable cb) {
+      m_cb = cb;
+    }
+
+    @Override
+    public void close() {
+      m_cb.run();
+    }
+  }
+
+  static class FailingAutoCloseableObject implements AutoCloseable {
+    public static final String message = "This is an expected failure";
+
+    @Override
+    public void close() {
+      throw new RuntimeException(message);
+    }
+  }
+
+  @Test
+  void cleanupStackWorks() {
+    List<AutoCloseableObject> objects = new ArrayList<>();
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+
+    try (CleanupPool pool = new CleanupPool()) {
+      for (AutoCloseableObject autoCloseableObject : objects) {
+        pool.register(autoCloseableObject);
+      }
+    }
+
+    for (AutoCloseableObject autoCloseableObject : objects) {
+      assertTrue(autoCloseableObject.m_closed);
+    }
+  }
+
+  @Test
+  @SuppressWarnings("PMD.AvoidCatchingGenericException")
+  void cleanupStackWithExceptionNotInCloseWorks() {
+    List<AutoCloseableObject> objects = new ArrayList<>();
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+
+    String message = "This is a known failure";
+
+    try (CleanupPool pool = new CleanupPool()) {
+      for (AutoCloseableObject autoCloseableObject : objects) {
+        pool.register(autoCloseableObject);
+      }
+      throw new Exception(message);
+    } catch (Exception e) {
+      assertEquals(message, e.getMessage());
+    }
+
+    for (AutoCloseableObject autoCloseableObject : objects) {
+      assertTrue(autoCloseableObject.m_closed);
+    }
+  }
+
+  @Test
+  @SuppressWarnings("PMD.AvoidCatchingGenericException")
+  void cleanupStackWithExceptionInCloseWorks() {
+    List<AutoCloseableObject> objects = new ArrayList<>();
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+
+    try (CleanupPool pool = new CleanupPool()) {
+      for (AutoCloseableObject autoCloseableObject : objects) {
+        pool.register(new FailingAutoCloseableObject());
+        pool.register(autoCloseableObject);
+      }
+    }
+
+    for (AutoCloseableObject autoCloseableObject : objects) {
+      assertTrue(autoCloseableObject.m_closed);
+    }
+  }
+
+  @Test
+  void cleanupStackRemovalWorks() {
+    List<AutoCloseableObject> objects = new ArrayList<>();
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+    objects.add(new AutoCloseableObject());
+
+    try (CleanupPool pool = new CleanupPool()) {
+      for (AutoCloseableObject autoCloseableObject : objects) {
+        pool.register(autoCloseableObject);
+      }
+
+      pool.remove(objects.get(0));
+    }
+
+    int idx = 0;
+    for (AutoCloseableObject autoCloseableObject : objects) {
+      if (idx == 0) {
+        assertFalse(autoCloseableObject.m_closed);
+      } else {
+        assertTrue(autoCloseableObject.m_closed);
+      }
+      idx++;
+    }
+  }
+
+  @Test
+  void cleanupStackIsLifo() {
+    List<AutoCloseableObjectWithCallback> objects = new ArrayList<>();
+    List<Integer> order = new ArrayList<>();
+    objects.add(new AutoCloseableObjectWithCallback(() -> order.add(0)));
+    objects.add(new AutoCloseableObjectWithCallback(() -> order.add(1)));
+    objects.add(new AutoCloseableObjectWithCallback(() -> order.add(2)));
+
+    try (CleanupPool pool = new CleanupPool()) {
+      for (AutoCloseable autoCloseableObject : objects) {
+        pool.register(autoCloseableObject);
+      }
+    }
+
+    assertEquals(order.size(), 3);
+    assertEquals(order.get(0), 2);
+    assertEquals(order.get(1), 1);
+    assertEquals(order.get(2), 0);
+  }
+}

wpiutil/src/test/java/edu/wpi/first/util/cleanup/ReflectionCleanupTest.java

@@ -0,0 +1,61 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.util.cleanup;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class ReflectionCleanupTest {
+  static class CleanupClass implements AutoCloseable {
+    public boolean m_closed;
+
+    @Override
+    public void close() {
+      m_closed = true;
+    }
+  }
+
+  static class CleanupTest implements ReflectionCleanup {
+    public CleanupClass m_class1 = new CleanupClass();
+    public CleanupClass m_class2 = new CleanupClass();
+    public Object m_nonCleanupObject = new Object();
+    public Object m_nullCleanupObject;
+
+    @Override
+    public void close() {
+      reflectionCleanup(CleanupTest.class);
+    }
+  }
+
+  static class CleanupTest2 extends CleanupTest {
+    @SkipCleanup public CleanupClass m_class3 = new CleanupClass();
+    public CleanupClass m_class4 = new CleanupClass();
+
+    @Override
+    public void close() {
+      reflectionCleanup(CleanupTest2.class);
+    }
+  }
+
+  @Test
+  void cleanupClosesAllFields() {
+    CleanupTest test = new CleanupTest();
+    test.close();
+    assertTrue(test.m_class1.m_closed);
+    assertTrue(test.m_class2.m_closed);
+  }
+
+  @Test
+  void cleanupOnlyClosesExplicitClassAndSkipWorks() {
+    CleanupTest2 test = new CleanupTest2();
+    test.close();
+    assertFalse(test.m_class1.m_closed);
+    assertFalse(test.m_class2.m_closed);
+    assertFalse(test.m_class3.m_closed);
+    assertTrue(test.m_class4.m_closed);
+  }
+}