Initial commit 🎉

fbshipit-source-id: b6fc29740c6875d2e78953b8a7123890a67930f2
Co-authored-by: Sebastian McKenzie <sebmck@fb.com>
Co-authored-by: John Knox <jknox@fb.com>
Co-authored-by: Emil Sjölander <emilsj@fb.com>
Co-authored-by: Pritesh Nandgaonkar <prit91@fb.com>

android/plugins/inspector/descriptors/utils/AndroidRootResolver.java

@@ -0,0 +1,102 @@
+/*
+ *  Copyright (c) 2018-present, Facebook, Inc.
+ *
+ *  This source code is licensed under the MIT license found in the LICENSE
+ *  file in the root directory of this source tree.
+ *
+ */
+
+package com.facebook.sonar.plugins.inspector.descriptors.utils;
+
+import static android.view.WindowManager.LayoutParams;
+
+import android.os.Build;
+import android.view.View;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import javax.annotation.Nullable;
+
+public final class AndroidRootResolver {
+
+  private static final String WINDOW_MANAGER_IMPL_CLAZZ = "android.view.WindowManagerImpl";
+  private static final String WINDOW_MANAGER_GLOBAL_CLAZZ = "android.view.WindowManagerGlobal";
+  private static final String VIEWS_FIELD = "mViews";
+  private static final String WINDOW_PARAMS_FIELD = "mParams";
+  private static final String GET_DEFAULT_IMPL = "getDefault";
+  private static final String GET_GLOBAL_INSTANCE = "getInstance";
+
+  private boolean initialized;
+  private Object windowManagerObj;
+  private Field viewsField;
+  private Field paramsField;
+
+  public static class Root {
+    public final View view;
+    public final LayoutParams param;
+
+    private Root(View view, LayoutParams param) {
+      this.view = view;
+      this.param = param;
+    }
+  }
+
+  public @Nullable List<Root> listActiveRoots() {
+    if (!initialized) {
+      initialize();
+    }
+
+    if (null == windowManagerObj) {
+      return null;
+    }
+
+    if (null == viewsField) {
+      return null;
+    }
+    if (null == paramsField) {
+      return null;
+    }
+
+    List<View> views = null;
+    List<LayoutParams> params = null;
+
+    try {
+      if (Build.VERSION.SDK_INT < 19) {
+        views = Arrays.asList((View[]) viewsField.get(windowManagerObj));
+        params = Arrays.asList((LayoutParams[]) paramsField.get(windowManagerObj));
+      } else {
+        views = (List<View>) viewsField.get(windowManagerObj);
+        params = (List<LayoutParams>) paramsField.get(windowManagerObj);
+      }
+    } catch (RuntimeException | IllegalAccessException re) {
+      return null;
+    }
+
+    List<Root> roots = new ArrayList<>();
+    for (int i = 0, stop = views.size(); i < stop; i++) {
+      roots.add(new Root(views.get(i), params.get(i)));
+    }
+    return roots;
+  }
+
+  private void initialize() {
+    initialized = true;
+    String accessClass =
+        Build.VERSION.SDK_INT > 16 ? WINDOW_MANAGER_GLOBAL_CLAZZ : WINDOW_MANAGER_IMPL_CLAZZ;
+    String instanceMethod = Build.VERSION.SDK_INT > 16 ? GET_GLOBAL_INSTANCE : GET_DEFAULT_IMPL;
+
+    try {
+      Class<?> clazz = Class.forName(accessClass);
+      Method getMethod = clazz.getMethod(instanceMethod);
+      windowManagerObj = getMethod.invoke(null);
+      viewsField = clazz.getDeclaredField(VIEWS_FIELD);
+      viewsField.setAccessible(true);
+      paramsField = clazz.getDeclaredField(WINDOW_PARAMS_FIELD);
+      paramsField.setAccessible(true);
+    } catch (InvocationTargetException | IllegalAccessException | RuntimeException | NoSuchMethodException | NoSuchFieldException | ClassNotFoundException ignored) {
+    }
+  }
+}