7 files changed, 307 insertions, 0 deletions
diff --git a/luni/src/main/java/android/compat/Compatibility.java b/luni/src/main/java/android/compat/Compatibility.java
new file mode 100644
index 0000000000..baf46bf950
--- /dev/null
+++ b/luni/src/main/java/android/compat/Compatibility.java
@@ -0,0 +1,109 @@
+/*
+ * 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 android.compat;
+
+import android.compat.annotation.ChangeId;
+
+import libcore.api.CorePlatformApi;
+import libcore.api.IntraCoreApi;
+
+/**
+ * Internal APIs for logging and gating compatibility changes.
+ *
+ * @see ChangeId
+ *
+ * @hide
+ */
+@CorePlatformApi
+@IntraCoreApi
+public final class Compatibility {
+
+    private Compatibility() {}
+
+    /**
+     * Reports that a compatibility change is affecting the current process now.
+     *
+     * <p>Calls to this method from a non-app process are ignored. This allows code implementing
+     * APIs that are used by apps and by other code (e.g. the system server) to report changes
+     * regardless of the process it's running in. When called in a non-app process, this method is
+     * a no-op.
+     *
+     * <p>Note: for changes that are gated using {@link #isChangeEnabled(long)}, you do not need to
+     * call this API directly. The change will be reported for you in the case that
+     * {@link #isChangeEnabled(long)} returns {@code true}.
+     *
+     * @param changeId The ID of the compatibility change taking effect.
+     */
+    @CorePlatformApi
+    @IntraCoreApi
+    public static void reportChange(@ChangeId long changeId) {
+        sCallbacks.reportChange(changeId);
+    }
+
+    /**
+     * Query if a given compatibility change is enabled for the current process. This method should
+     * only be called by code running inside a process of the affected app.
+     *
+     * <p>If this method returns {@code true}, the calling code should implement the compatibility
+     * change, resulting in differing behaviour compared to earlier releases. If this method returns
+     * {@code false}, the calling code should behave as it did in earlier releases.
+     *
+     * <p>When this method returns {@code true}, it will also report the change as
+     * {@link #reportChange(long)} would, so there is no need to call that method directly.
+     *
+     * @param changeId The ID of the compatibility change in question.
+     * @return {@code true} if the change is enabled for the current app.
+     */
+    @CorePlatformApi
+    @IntraCoreApi
+    public static boolean isChangeEnabled(@ChangeId long changeId) {
+        return sCallbacks.isChangeEnabled(changeId);
+    }
+
+    private volatile static Callbacks sCallbacks = new Callbacks();
+
+    @CorePlatformApi
+    public static void setCallbacks(Callbacks callbacks) {
+        sCallbacks = callbacks;
+    }
+
+    /**
+     * Base class for compatibility API implementations. The default implementation logs a warning
+     * to logcat.
+     *
+     * This is provided as a class rather than an interface to allow new methods to be added without
+     * breaking @CorePlatformApi binary compatibility.
+     */
+    @CorePlatformApi
+    public static class Callbacks {
+        @CorePlatformApi
+        protected Callbacks() {
+        }
+        @CorePlatformApi
+        protected void reportChange(long changeId) {
+            System.logW(String.format(
+                    "No Compatibility callbacks set! Reporting change %d", changeId));
+        }
+        @CorePlatformApi
+        protected boolean isChangeEnabled(long changeId) {
+            System.logW(String.format(
+                    "No Compatibility callbacks set! Querying change %d", changeId));
+            return true;
+        }
+    }
+
+}
diff --git a/luni/src/main/java/android/compat/annotation/ChangeId.java b/luni/src/main/java/android/compat/annotation/ChangeId.java
new file mode 100644
index 0000000000..ea91223fd2
--- /dev/null
+++ b/luni/src/main/java/android/compat/annotation/ChangeId.java
@@ -0,0 +1,51 @@
+/*
+ * 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 android.compat.annotation;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.RetentionPolicy.CLASS;
+
+import libcore.api.CorePlatformApi;
+import libcore.api.IntraCoreApi;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that a field is a compatibility change ID.
+ *
+ * <p>A compatibility change is a change to the Android platform that may impact app behavior,
+ * relative to previous releases of Android. A change ID is a unique {@code long} identifying one
+ * such change. Compatibility change IDs should be defined as a {@code static final long}:
+ *
+ * <pre>{@code
+ *     @ChangeId
+ *     public static final long MY_CHANGE_ID = 123456789l;
+ * }</pre>
+ *
+ * <p>The value of the constant is the ID of an issue in <a href="https://issuetracker.google.com/">
+ * buganizer</a>.
+ *
+ * @hide
+ */
+@Retention(CLASS)
+@Target({FIELD, PARAMETER})
+@CorePlatformApi
+@IntraCoreApi
+public @interface ChangeId {
+}
diff --git a/luni/src/main/java/android/compat/annotation/Disabled.java b/luni/src/main/java/android/compat/annotation/Disabled.java
new file mode 100644
index 0000000000..4779a24f7e
--- /dev/null
+++ b/luni/src/main/java/android/compat/annotation/Disabled.java
@@ -0,0 +1,41 @@
+/*
+ * 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 android.compat.annotation;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.RetentionPolicy.CLASS;
+
+import libcore.api.CorePlatformApi;
+import libcore.api.IntraCoreApi;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Used to indicate that a compatibility {@link ChangeId change} is disabled for all apps.
+ *
+ * <p>This annotation should only be applied to change ID constants that are also annotated with
+ * {@link ChangeId}. In any other context, this annotation will have no effect.
+ *
+ * @hide
+ */
+@Retention(CLASS)
+@Target({FIELD})
+@CorePlatformApi
+@IntraCoreApi
+public @interface Disabled {
+}
diff --git a/luni/src/main/java/android/compat/annotation/EnabledAfter.java b/luni/src/main/java/android/compat/annotation/EnabledAfter.java
new file mode 100644
index 0000000000..aeb62fdf1a
--- /dev/null
+++ b/luni/src/main/java/android/compat/annotation/EnabledAfter.java
@@ -0,0 +1,49 @@
+/*
+ * 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 android.compat.annotation;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.RetentionPolicy.CLASS;
+
+import libcore.api.CorePlatformApi;
+import libcore.api.IntraCoreApi;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+/**
+ * Used to indicate that a compatibility {@link ChangeId change} is enabled only for apps with a
+ * {@code targetSdkVersion} of <em>greater than</em> the given value.
+ *
+ * <p>This annotation should only be applied to change ID constants that are also annotated with
+ * {@link ChangeId}. In any other context, this annotation will have no effect.
+ *
+ * @hide
+ */
+@Retention(CLASS)
+@Target({FIELD})
+@CorePlatformApi
+@IntraCoreApi
+public @interface EnabledAfter {
+  /**
+   * @return The maximum {@code targetSdkVersion} for which this change does not apply. Apps with
+   *     a {@code targetSdkVersion} of greater than this value will get the change.
+   */
+  @CorePlatformApi
+  @IntraCoreApi
+  int targetSdkVersion();
+}
diff --git a/mmodules/core_platform_api/api/platform/current-api.txt b/mmodules/core_platform_api/api/platform/current-api.txt
index d59d230de1..52c2bc54b6 100644
--- a/mmodules/core_platform_api/api/platform/current-api.txt
+++ b/mmodules/core_platform_api/api/platform/current-api.txt
@@ -1,4 +1,34 @@
 // Signature format: 2.0
+package android.compat {
+
+  public final class Compatibility {
+    method public static boolean isChangeEnabled(@android.compat.annotation.ChangeId long);
+    method public static void reportChange(@android.compat.annotation.ChangeId long);
+    method public static void setCallbacks(android.compat.Compatibility.Callbacks);
+  }
+
+  public static class Compatibility.Callbacks {
+    ctor protected Compatibility.Callbacks();
+    method protected boolean isChangeEnabled(long);
+    method protected void reportChange(long);
+  }
+
+}
+
+package android.compat.annotation {
+
+  @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.CLASS) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD, java.lang.annotation.ElementType.PARAMETER}) public @interface ChangeId {
+  }
+
+  @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.CLASS) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD}) public @interface Disabled {
+  }
+
+  @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.CLASS) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD}) public @interface EnabledAfter {
+    method public abstract int targetSdkVersion();
+  }
+
+}
+
 package android.icu.impl {
 
   public class CalendarAstronomer {
diff --git a/mmodules/intracoreapi/api/intra/current-api.txt b/mmodules/intracoreapi/api/intra/current-api.txt
index 4250d3fc9a..4eeebc27da 100644
--- a/mmodules/intracoreapi/api/intra/current-api.txt
+++ b/mmodules/intracoreapi/api/intra/current-api.txt
@@ -1,4 +1,27 @@
 // Signature format: 2.0
+package android.compat {
+
+  @libcore.api.CorePlatformApi @libcore.api.IntraCoreApi public final class Compatibility {
+    method @libcore.api.CorePlatformApi @libcore.api.IntraCoreApi public static boolean isChangeEnabled(@android.compat.annotation.ChangeId long);
+    method @libcore.api.CorePlatformApi @libcore.api.IntraCoreApi public static void reportChange(@android.compat.annotation.ChangeId long);
+  }
+
+}
+
+package android.compat.annotation {
+
+  @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.CLASS) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD, java.lang.annotation.ElementType.PARAMETER}) @libcore.api.CorePlatformApi @libcore.api.IntraCoreApi public @interface ChangeId {
+  }
+
+  @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.CLASS) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD}) @libcore.api.CorePlatformApi @libcore.api.IntraCoreApi public @interface Disabled {
+  }
+
+  @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.CLASS) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD}) @libcore.api.CorePlatformApi @libcore.api.IntraCoreApi public @interface EnabledAfter {
+    method @libcore.api.CorePlatformApi @libcore.api.IntraCoreApi public abstract int targetSdkVersion();
+  }
+
+}
+
 package com.android.org.conscrypt {
 
   @libcore.api.IntraCoreApi public class DESEDESecretKeyFactory extends javax.crypto.SecretKeyFactorySpi {
diff --git a/non_openjdk_java_files.bp b/non_openjdk_java_files.bp
index 982c02a442..caf3c996d8 100644
--- a/non_openjdk_java_files.bp
+++ b/non_openjdk_java_files.bp
@@ -1,6 +1,10 @@
 filegroup {
     name: "non_openjdk_javadoc_files",
     srcs: [
+        "luni/src/main/java/android/compat/annotation/ChangeId.java",
+        "luni/src/main/java/android/compat/annotation/Disabled.java",
+        "luni/src/main/java/android/compat/annotation/EnabledAfter.java",
+        "luni/src/main/java/android/compat/Compatibility.java",
         "luni/src/main/java/android/system/ErrnoException.java",
         "luni/src/main/java/android/system/GaiException.java",
         "luni/src/main/java/android/system/IcmpHeaders.java",