Revert^2 "A new Client-Side FeatureFlags library."
4765b4597b950a623cb61c275596119be6e2dacd
Bug: 279054964
Change-Id: I9bb79e6f6503af780406a989d79a50c2881db5db
diff --git a/core/java/android/flags/BooleanFlag.java b/core/java/android/flags/BooleanFlag.java
new file mode 100644
index 0000000..5519961
--- /dev/null
+++ b/core/java/android/flags/BooleanFlag.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+import android.annotation.NonNull;
+
+/**
+ * A flag representing a true or false value.
+ *
+ * The value will always be the same during the lifetime of the process it is read in.
+ *
+ * @hide
+ */
+public class BooleanFlag implements Flag<Boolean> {
+ private final String mNamespace;
+ private final String mName;
+ private final boolean mDefault;
+
+ /**
+ * @param namespace A namespace for this flag. See {@link android.provider.DeviceConfig}.
+ * @param name A name for this flag.
+ * @param defaultValue The value of this flag if no other override is present.
+ */
+ BooleanFlag(String namespace, String name, boolean defaultValue) {
+ mNamespace = namespace;
+ mName = name;
+ mDefault = defaultValue;
+ }
+
+ @Override
+ @NonNull
+ public Boolean getDefault() {
+ return mDefault;
+ }
+
+ @Override
+ @NonNull
+ public String getNamespace() {
+ return mNamespace;
+ }
+
+ @Override
+ @NonNull
+ public String getName() {
+ return mName;
+ }
+
+ @Override
+ @NonNull
+ public String toString() {
+ return getNamespace() + "." + getName() + "[" + getDefault() + "]";
+ }
+}
diff --git a/core/java/android/flags/DynamicBooleanFlag.java b/core/java/android/flags/DynamicBooleanFlag.java
new file mode 100644
index 0000000..d76fd9e
--- /dev/null
+++ b/core/java/android/flags/DynamicBooleanFlag.java
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+/**
+ * A flag representing a true or false value.
+ *
+ * The value may be different from one read to the next.
+ *
+ * @hide
+ */
+public class DynamicBooleanFlag implements DynamicFlag<Boolean> {
+
+ private final String mNamespace;
+ private final String mName;
+ private final boolean mDefault;
+
+ /**
+ * @param namespace A namespace for this flag. See {@link android.provider.DeviceConfig}.
+ * @param name A name for this flag.
+ * @param defaultValue The value of this flag if no other override is present.
+ */
+ DynamicBooleanFlag(String namespace, String name, boolean defaultValue) {
+ mNamespace = namespace;
+ mName = name;
+ mDefault = defaultValue;
+ }
+
+ @Override
+ public String getNamespace() {
+ return mNamespace;
+ }
+
+ @Override
+ public String getName() {
+ return mName;
+ }
+
+ @Override
+ public Boolean getDefault() {
+ return mDefault;
+ }
+
+ @Override
+ public String toString() {
+ return getNamespace() + "." + getName() + "[" + getDefault() + "]";
+ }
+}
diff --git a/core/java/android/flags/DynamicFlag.java b/core/java/android/flags/DynamicFlag.java
new file mode 100644
index 0000000..8583ea6
--- /dev/null
+++ b/core/java/android/flags/DynamicFlag.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+/**
+ * A flag for which the value may be different from one read to the next.
+ *
+ * @param <T> The type of value that this flag stores. E.g. Boolean or String.
+ *
+ * @hide
+ */
+public interface DynamicFlag<T> extends Flag<T> {
+}
diff --git a/core/java/android/flags/FeatureFlags.java b/core/java/android/flags/FeatureFlags.java
new file mode 100644
index 0000000..c7d9d57
--- /dev/null
+++ b/core/java/android/flags/FeatureFlags.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+import android.annotation.NonNull;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * A class for querying constants from the system - primarily booleans.
+ *
+ * Clients using this class can define their flags and their default values in one place,
+ * can override those values on running devices for debugging and testing purposes, and can control
+ * what flags are available to be used on release builds.
+ *
+ * TODO(b/279054964): A lot. This is skeleton code right now.
+ * @hide
+ */
+public class FeatureFlags {
+ private static FeatureFlags sInstance;
+ private static final Object sInstanceLock = new Object();
+
+ private final Set<ChangeListener> mListeners = new HashSet<>();
+
+ /**
+ * Obtain a per-process instance of FeatureFlags.
+ * @return
+ */
+ @NonNull
+ public static FeatureFlags getInstance() {
+ synchronized (sInstanceLock) {
+ if (sInstance == null) {
+ sInstance = new FeatureFlags();
+ }
+ }
+
+ return sInstance;
+ }
+
+ FeatureFlags() {
+ }
+
+ /**
+ * Returns whether the supplied flag is true or not.
+ *
+ * {@link BooleanFlag} should only be used in debug builds. They do not get optimized out.
+ *
+ * The first time a flag is read, its value is cached for the lifetime of the process.
+ */
+ public boolean isEnabled(@NonNull BooleanFlag flag) {
+ return flag.getDefault();
+ }
+
+ /**
+ * Returns whether the supplied flag is true or not.
+ *
+ * Always returns false.
+ */
+ public boolean isEnabled(@NonNull FusedOffFlag flag) {
+ return false;
+ }
+
+ /**
+ * Returns whether the supplied flag is true or not.
+ *
+ * Always returns true;
+ */
+ public boolean isEnabled(@NonNull FusedOnFlag flag) {
+ return true;
+ }
+
+ /**
+ * Returns whether the supplied flag is true or not.
+ *
+ * Can return a different value for the flag each time it is called if an override comes in.
+ */
+ public boolean isCurrentlyEnabled(@NonNull DynamicBooleanFlag flag) {
+ return flag.getDefault();
+ }
+
+ /**
+ * Add a listener to be alerted when a {@link DynamicFlag} changes.
+ *
+ * See also {@link #removeChangeListener(ChangeListener)}.
+ *
+ * @param listener The listener to add.
+ */
+ public void addChangeListener(@NonNull ChangeListener listener) {
+ mListeners.add(listener);
+ }
+
+ /**
+ * Remove a listener that was added earlier.
+ *
+ * See also {@link #addChangeListener(ChangeListener)}.
+ *
+ * @param listener The listener to remove.
+ */
+ public void removeChangeListener(@NonNull ChangeListener listener) {
+ mListeners.remove(listener);
+ }
+
+ /**
+ * A simpler listener that is alerted when a {@link DynamicFlag} changes.
+ *
+ * See {@link #addChangeListener(ChangeListener)}
+ */
+ public interface ChangeListener {
+ /**
+ * Called when a {@link DynamicFlag} changes.
+ *
+ * @param flag The flag that has changed.
+ */
+ void onFlagChanged(DynamicFlag<?> flag);
+ }
+}
diff --git a/core/java/android/flags/FeatureFlagsFake.java b/core/java/android/flags/FeatureFlagsFake.java
new file mode 100644
index 0000000..03bf2b6
--- /dev/null
+++ b/core/java/android/flags/FeatureFlagsFake.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+import android.annotation.NonNull;
+
+/**
+ * An implementation of {@link FeatureFlags} for testing.
+ * @hide
+ */
+public class FeatureFlagsFake extends FeatureFlags {
+ public FeatureFlagsFake() {
+ super();
+ }
+
+ @Override
+ public boolean isEnabled(@NonNull BooleanFlag flag) {
+ return flag.getDefault();
+ }
+
+ @Override
+ public boolean isEnabled(@NonNull FusedOffFlag flag) {
+ return false;
+ }
+
+ @Override
+ public boolean isEnabled(@NonNull FusedOnFlag flag) {
+ return true;
+ }
+
+ @Override
+ public boolean isCurrentlyEnabled(@NonNull DynamicBooleanFlag flag) {
+ return flag.getDefault();
+ }
+}
diff --git a/core/java/android/flags/Flag.java b/core/java/android/flags/Flag.java
new file mode 100644
index 0000000..ae0a6ba
--- /dev/null
+++ b/core/java/android/flags/Flag.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+import android.annotation.NonNull;
+
+/**
+ * Base class for constants read via {@link android.flags.FeatureFlags}.
+ *
+ * @param <T> The type of value that this flag stores. E.g. Boolean or String.
+ *
+ * @hide
+ */
+public interface Flag<T> {
+ /** The namespace for a flag. Should combine uniquely with its name. */
+ @NonNull
+ String getNamespace();
+
+ /** The name of the flag. Should combine uniquely with its namespace. */
+ @NonNull
+ String getName();
+
+ /** The value of this flag if no override has been set. Null values are not supported. */
+ @NonNull
+ T getDefault();
+}
diff --git a/core/java/android/flags/FusedOffFlag.java b/core/java/android/flags/FusedOffFlag.java
new file mode 100644
index 0000000..999d0f9
--- /dev/null
+++ b/core/java/android/flags/FusedOffFlag.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+import android.annotation.NonNull;
+
+/**
+ * A flag representing a false value.
+ *
+ * The flag can never be changed or overridden. It is false at compile time.
+ *
+ * @hide
+ */
+public final class FusedOffFlag implements Flag<Boolean> {
+ private final String mNamespace;
+ private final String mName;
+
+ FusedOffFlag(String namespace, String name) {
+ mNamespace = namespace;
+ mName = name;
+ }
+
+ @Override
+ @NonNull
+ public Boolean getDefault() {
+ return false;
+ }
+
+ @Override
+ @NonNull
+ public String getNamespace() {
+ return mNamespace;
+ }
+
+ @Override
+ @NonNull
+ public String getName() {
+ return mName;
+ }
+
+ @Override
+ @NonNull
+ public String toString() {
+ return getNamespace() + "." + getName() + "[false]";
+ }
+}
diff --git a/core/java/android/flags/FusedOnFlag.java b/core/java/android/flags/FusedOnFlag.java
new file mode 100644
index 0000000..4f33bee
--- /dev/null
+++ b/core/java/android/flags/FusedOnFlag.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2023 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.flags;
+
+import android.annotation.NonNull;
+
+/**
+ * A flag representing a true value.
+ *
+ * The flag can never be changed or overridden. It is true at compile time.
+ *
+ * @hide
+ */
+public final class FusedOnFlag implements Flag<Boolean> {
+ private final String mNamespace;
+ private final String mName;
+
+ FusedOnFlag(String namespace, String name) {
+ mNamespace = namespace;
+ mName = name;
+ }
+
+ @Override
+ @NonNull
+ public Boolean getDefault() {
+ return true;
+ }
+
+ @Override
+ @NonNull
+ public String getNamespace() {
+ return mNamespace;
+ }
+
+ @Override
+ @NonNull
+ public String getName() {
+ return mName;
+ }
+
+ @Override
+ @NonNull
+ public String toString() {
+ return getNamespace() + "." + getName() + "[true]";
+ }
+}
diff --git a/core/java/android/flags/OWNERS b/core/java/android/flags/OWNERS
new file mode 100644
index 0000000..fa125c4
--- /dev/null
+++ b/core/java/android/flags/OWNERS
@@ -0,0 +1,7 @@
+# Bug component: 1306523
+
+mankoff@google.com
+pixel@google.com
+
+dsandler@android.com
+
diff --git a/core/tests/coretests/src/android/flags/FeatureFlagsTest.java b/core/tests/coretests/src/android/flags/FeatureFlagsTest.java
new file mode 100644
index 0000000..dc6006a
--- /dev/null
+++ b/core/tests/coretests/src/android/flags/FeatureFlagsTest.java
@@ -0,0 +1,54 @@
+/*
+ * 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.flags;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.platform.test.annotations.Presubmit;
+
+import androidx.test.filters.SmallTest;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.mockito.MockitoAnnotations;
+
+@SmallTest
+@Presubmit
+public final class FeatureFlagsTest {
+
+ @Before
+ public void setup() {
+ MockitoAnnotations.initMocks(this);
+ }
+
+ @After
+ public void tearDown() {
+ }
+
+ @Test
+ public void testPass() {
+ assertThat(true).isTrue();
+ }
+
+ @Ignore
+ @Test
+ public void testFail() {
+ assertThat(false).isTrue();
+ }
+}