Introduce @(Non)UiContext and @DisplayContext

This annotations is used for marking generic Context.
It will be furthur used for lint checks.

Test: flash and build
Bug: 151414704
Change-Id: Ic17f4f7f393590b5f8403bf978e168ea3fc3d39c

core/java/android/annotation/DisplayContext.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2020 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 android.annotation;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import android.app.Activity;
+import android.app.WallpaperManager;
+import android.content.Context;
+import android.os.Bundle;
+import android.view.Display;
+import android.view.LayoutInflater;
+import android.view.WindowManager;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Denotes a {@link Context} that is tied to a {@link Display} and can be used to obtain one
+ * via {@link Context#getDisplay}, but <b>may not</b> be able to obtain {@link WindowManager},
+ * {@link LayoutInflater} or {@link WallpaperManager} via {@link Context#getSystemService(String)}.
+ * If the UI services mentioned above are required, please use contexts which are marked as
+ * {@link UiContext}.
+ * <p>
+ * {@link Activity}, and the result of {@link Context#createWindowContext(int, Bundle)} or
+ * {@link Context#createDisplayContext(Display)} can be
+ * used where a {@link DisplayContext} is required.
+ * <p>
+ * This is a marker annotation and has no specific attributes.
+ *
+ * @see Context#getDisplay()
+ * @see Context#getSystemService(String)
+ * @see Context#getSystemService(Class)
+ * @see Context#createDisplayContext(Display)
+ * @see Context#createWindowContext(int, Bundle)
+ * @see UiContext
+ * @hide
+ */
+@Retention(SOURCE)
+@Target({TYPE, METHOD, PARAMETER, FIELD})
+public @interface DisplayContext {
+}

core/java/android/annotation/NonUiContext.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2020 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 android.annotation;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import android.app.WallpaperManager;
+import android.content.Context;
+import android.view.Display;
+import android.view.LayoutInflater;
+import android.view.WindowManager;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Denotes a {@link Context} that <b>can not</b> be used to obtain a {@link Display} via
+ * {@link Context#getDisplay} nor to obtain a {@link WindowManager}, {@link LayoutInflater} or
+ * {@link WallpaperManager} via {@link Context#getSystemService(String)}.
+ * <p>
+ * This is a marker annotation and has no specific attributes.
+ *
+ * @see Context#getDisplay()
+ * @see Context#getSystemService(String)
+ * @see Context#getSystemService(Class)
+ * @hide
+ */
+@Retention(SOURCE)
+@Target({TYPE, METHOD, PARAMETER, FIELD})
+public @interface NonUiContext {
+}

core/java/android/annotation/UiContext.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2020 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 android.annotation;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.SOURCE;
+
+import android.app.Activity;
+import android.app.WallpaperManager;
+import android.content.Context;
+import android.os.Bundle;
+import android.view.Display;
+import android.view.LayoutInflater;
+import android.view.WindowManager;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Denotes a {@link Context} that can be used to create UI, meaning that it can provide a
+ * {@link Display} via {@link Context#getDisplay} and can be used to obtain a {@link WindowManager},
+ * {@link LayoutInflater} or {@link WallpaperManager} via {@link Context#getSystemService(String)}.
+ * A {@link Context} which is marked as {@link UiContext} implies that the {@link Context} is also
+ * a {@link DisplayContext}.
+ * <p>
+ * This kind of {@link Context} is usually an {@link Activity} or
+ * created via {@link Context#createWindowContext(int, Bundle)}.
+ * </p>
+ * This is a marker annotation and has no specific attributes.
+ *
+ * @see Context#getDisplay()
+ * @see Context#getSystemService(String)
+ * @see Context#getSystemService(Class)
+ * @see Context#createWindowContext(int, Bundle)
+ * @see DisplayContext
+ * @hide
+ */
+@Retention(SOURCE)
+@Target({TYPE, METHOD, PARAMETER, FIELD})
+public @interface UiContext {
+}