Connect FeatureFlags with FeatureFlagsService. (f593888d) · Commits · e / os / android_frameworks_base

core/java/android/flags/BooleanFlag.java

+2 −23

Original line number	Diff line number	Diff line
		@@ -25,9 +25,7 @@ import android.annotation.NonNull;
		*
		* @hide
		*/
		public class BooleanFlag implements Flag<Boolean> {
		private final String mNamespace;
		private final String mName;
		public class BooleanFlag extends BooleanFlagBase {
		private final boolean mDefault;

		/**
		@@ -36,8 +34,7 @@ public class BooleanFlag implements Flag<Boolean> {
		* @param defaultValue The value of this flag if no other override is present.
		*/
		BooleanFlag(String namespace, String name, boolean defaultValue) {
		mNamespace = namespace;
		mName = name;
		super(namespace, name);
		mDefault = defaultValue;
		}

		@@ -46,22 +43,4 @@ public class BooleanFlag implements Flag<Boolean> {
		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() + "]";
		}
		}

core/java/android/flags/BooleanFlagBase.java

0 → 100644

+54 −0

Original line number	Diff line number	Diff line
		/*
		* 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;

		abstract class BooleanFlagBase implements Flag<Boolean> {

		private final String mNamespace;
		private final String mName;

		/**
		* @param namespace A namespace for this flag. See {@link android.provider.DeviceConfig}.
		* @param name A name for this flag.
		*/
		BooleanFlagBase(String namespace, String name) {
		mNamespace = namespace;
		mName = name;
		}

		public abstract Boolean getDefault();

		@Override
		@NonNull
		public String getNamespace() {
		return mNamespace;
		}

		@Override
		@NonNull
		public String getName() {
		return mName;
		}

		@Override
		@NonNull
		public String toString() {
		return getNamespace() + "." + getName() + "[" + getDefault() + "]";
		}
		}

core/java/android/flags/DynamicBooleanFlag.java

+2 −20

Original line number	Diff line number	Diff line
		@@ -23,10 +23,8 @@ package android.flags;
		*
		* @hide
		*/
		public class DynamicBooleanFlag implements DynamicFlag<Boolean> {
		public class DynamicBooleanFlag extends BooleanFlagBase implements DynamicFlag<Boolean> {

		private final String mNamespace;
		private final String mName;
		private final boolean mDefault;

		/**
		@@ -35,28 +33,12 @@ public class DynamicBooleanFlag implements DynamicFlag<Boolean> {
		* @param defaultValue The value of this flag if no other override is present.
		*/
		DynamicBooleanFlag(String namespace, String name, boolean defaultValue) {
		mNamespace = namespace;
		mName = name;
		super(namespace, 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() + "]";
		}
		}

core/java/android/flags/FeatureFlags.java

+260 −19

Original line number	Diff line number	Diff line
		@@ -17,8 +17,19 @@
		package android.flags;

		import android.annotation.NonNull;
		import android.content.Context;
		import android.os.RemoteException;
		import android.os.ServiceManager;
		import android.util.ArraySet;
		import android.util.Log;

		import com.android.internal.annotations.VisibleForTesting;

		import java.util.ArrayList;
		import java.util.HashMap;
		import java.util.HashSet;
		import java.util.List;
		import java.util.Map;
		import java.util.Set;

		/**
		@@ -32,14 +43,20 @@ import java.util.Set;
		* @hide
		*/
		public class FeatureFlags {
		private static final String TAG = "FeatureFlags";
		private static FeatureFlags sInstance;
		private static final Object sInstanceLock = new Object();

		private final Set<Flag<?>> mKnownFlags = new ArraySet<>();
		private final Set<Flag<?>> mDirtyFlags = new ArraySet<>();

		private IFeatureFlags mIFeatureFlags;
		private final Map<String, Map<String, Boolean>> mBooleanOverrides = new HashMap<>();
		private final Set<ChangeListener> mListeners = new HashSet<>();

		/**
		* Obtain a per-process instance of FeatureFlags.
		* @return
		* @return A singleton instance of {@link FeatureFlags}.
		*/
		@NonNull
		public static FeatureFlags getInstance() {
		@@ -52,7 +69,124 @@ public class FeatureFlags {
		return sInstance;
		}

		FeatureFlags() {
		/** See {@link FeatureFlagsFake}. */
		@VisibleForTesting(visibility = VisibleForTesting.Visibility.PRIVATE)
		public static void setInstance(FeatureFlags instance) {
		synchronized (sInstanceLock) {
		sInstance = instance;
		}
		}

		private final IFeatureFlagsCallback mIFeatureFlagsCallback = new IFeatureFlagsCallback.Stub() {
		@Override
		public void onFlagChange(SyncableFlag flag) {
		for (Flag<?> f : mKnownFlags) {
		if (flagEqualsSyncableFlag(f, flag)) {
		if (f instanceof DynamicFlag<?>) {
		if (f instanceof DynamicBooleanFlag) {
		String value = flag.getValue();
		if (value == null) { // Null means any existing overrides were erased.
		value = ((DynamicBooleanFlag) f).getDefault().toString();
		}
		addBooleanOverride(flag.getNamespace(), flag.getName(), value);
		}
		FeatureFlags.this.onFlagChange((DynamicFlag<?>) f);
		}
		break;
		}
		}
		}
		};

		private FeatureFlags() {
		this(null);
		}

		@VisibleForTesting(visibility = VisibleForTesting.Visibility.PRIVATE)
		public FeatureFlags(IFeatureFlags iFeatureFlags) {
		mIFeatureFlags = iFeatureFlags;

		if (mIFeatureFlags != null) {
		try {
		mIFeatureFlags.registerCallback(mIFeatureFlagsCallback);
		} catch (RemoteException e) {
		// Won't happen in tests.
		}
		}
		}

		/**
		* Construct a new {@link BooleanFlag}.
		*
		* Use this instead of constructing a {@link BooleanFlag} directly, as it registers the flag
		* with the internals of the flagging system.
		*/
		@NonNull
		public static BooleanFlag booleanFlag(
		@NonNull String namespace, @NonNull String name, boolean def) {
		return getInstance().addFlag(new BooleanFlag(namespace, name, def));
		}

		/**
		* Construct a new {@link FusedOffFlag}.
		*
		* Use this instead of constructing a {@link FusedOffFlag} directly, as it registers the
		* flag with the internals of the flagging system.
		*/
		@NonNull
		public static FusedOffFlag fusedOffFlag(@NonNull String namespace, @NonNull String name) {
		return getInstance().addFlag(new FusedOffFlag(namespace, name));
		}

		/**
		* Construct a new {@link FusedOnFlag}.
		*
		* Use this instead of constructing a {@link FusedOnFlag} directly, as it registers the flag
		* with the internals of the flagging system.
		*/
		@NonNull
		public static FusedOnFlag fusedOnFlag(@NonNull String namespace, @NonNull String name) {
		return getInstance().addFlag(new FusedOnFlag(namespace, name));
		}

		/**
		* Construct a new {@link DynamicBooleanFlag}.
		*
		* Use this instead of constructing a {@link DynamicBooleanFlag} directly, as it registers
		* the flag with the internals of the flagging system.
		*/
		@NonNull
		public static DynamicBooleanFlag dynamicBooleanFlag(
		@NonNull String namespace, @NonNull String name, boolean def) {
		return getInstance().addFlag(new DynamicBooleanFlag(namespace, name, def));
		}

		/**
		* 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);
		}

		protected void onFlagChange(@NonNull DynamicFlag<?> flag) {
		for (ChangeListener l : mListeners) {
		l.onFlagChanged(flag);
		}
		}

		/**
		@@ -63,7 +197,7 @@ public class FeatureFlags {
		* 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();
		return getBooleanInternal(flag);
		}

		/**
		@@ -90,31 +224,138 @@ public class FeatureFlags {
		* 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();
		return getBooleanInternal(flag);
		}

		/**
		* 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);
		private boolean getBooleanInternal(Flag<Boolean> flag) {
		sync();
		Map<String, Boolean> ns = mBooleanOverrides.get(flag.getNamespace());
		Boolean value = null;
		if (ns != null) {
		value = ns.get(flag.getName());
		}
		if (value == null) {
		throw new IllegalStateException("Boolean flag being read but was not synced: " + flag);
		}

		return value;
		}

		private <T extends Flag<?>> T addFlag(T flag) {
		synchronized (FeatureFlags.class) {
		mDirtyFlags.add(flag);
		mKnownFlags.add(flag);
		}
		return flag;
		}

		protected void sync() {
		synchronized (FeatureFlags.class) {
		if (mDirtyFlags.isEmpty()) {
		return;
		}
		syncInternal(mDirtyFlags);
		mDirtyFlags.clear();
		}
		}

		/**
		* Remove a listener that was added earlier.
		* Called when new flags have been declared. Gives the implementation a chance to act on them.
		*
		* See also {@link #addChangeListener(ChangeListener)}.
		*
		* @param listener The listener to remove.
		* Guaranteed to be called from a synchronized, thread-safe context.
		*/
		public void removeChangeListener(@NonNull ChangeListener listener) {
		mListeners.remove(listener);
		protected void syncInternal(Set<Flag<?>> dirtyFlags) {
		IFeatureFlags iFeatureFlags = bind();
		List<SyncableFlag> syncableFlags = new ArrayList<>();
		for (Flag<?> f : dirtyFlags) {
		syncableFlags.add(flagToSyncableFlag(f));
		}

		List<SyncableFlag> serverFlags = List.of(); // Need to initialize the list with something.
		try {
		// New values come back from the service.
		serverFlags = iFeatureFlags.syncFlags(syncableFlags);
		} catch (RemoteException e) {
		e.rethrowFromSystemServer();
		}

		for (Flag<?> f : dirtyFlags) {
		boolean found = false;
		for (SyncableFlag sf : serverFlags) {
		if (flagEqualsSyncableFlag(f, sf)) {
		if (f instanceof BooleanFlag \|\| f instanceof DynamicBooleanFlag) {
		addBooleanOverride(sf.getNamespace(), sf.getName(), sf.getValue());
		}
		found = true;
		break;
		}
		}
		if (!found) {
		if (f instanceof BooleanFlag) {
		addBooleanOverride(
		f.getNamespace(),
		f.getName(),
		((BooleanFlag) f).getDefault() ? "true" : "false");
		}
		}
		}
		}

		private void addBooleanOverride(String namespace, String name, String override) {
		Map<String, Boolean> nsOverrides = mBooleanOverrides.get(namespace);
		if (nsOverrides == null) {
		nsOverrides = new HashMap<>();
		mBooleanOverrides.put(namespace, nsOverrides);
		}
		nsOverrides.put(name, parseBoolean(override));
		}

		private SyncableFlag flagToSyncableFlag(Flag<?> f) {
		return new SyncableFlag(
		f.getNamespace(),
		f.getName(),
		f.getDefault().toString(),
		f instanceof DynamicFlag<?>);
		}

		private IFeatureFlags bind() {
		if (mIFeatureFlags == null) {
		mIFeatureFlags = IFeatureFlags.Stub.asInterface(
		ServiceManager.getService(Context.FEATURE_FLAGS_SERVICE));
		try {
		mIFeatureFlags.registerCallback(mIFeatureFlagsCallback);
		} catch (RemoteException e) {
		Log.e(TAG, "Failed to listen for flag changes!");
		}
		}

		return mIFeatureFlags;
		}

		static boolean parseBoolean(String value) {
		// Check for a truish string.
		boolean result = value.equalsIgnoreCase("true")
		\|\| value.equals("1")
		\|\| value.equalsIgnoreCase("t")
		\|\| value.equalsIgnoreCase("on");
		if (!result) { // Expect a falsish string, else log an error.
		if (!(value.equalsIgnoreCase("false")
		\|\| value.equals("0")
		\|\| value.equalsIgnoreCase("f")
		\|\| value.equalsIgnoreCase("off"))) {
		Log.e(TAG,
		"Tried parsing " + value + " as boolean but it doesn't look like one. "
		+ "Value expected to be one of true\|false, 1\|0, t\|f, on\|off.");
		}
		}
		return result;
		}

		private static boolean flagEqualsSyncableFlag(Flag<?> f, SyncableFlag sf) {
		return f.getName().equals(sf.getName()) && f.getNamespace().equals(sf.getNamespace());
		}


		/**
		* A simpler listener that is alerted when a {@link DynamicFlag} changes.
		*

core/java/android/flags/FeatureFlagsFake.java

+72 −6

Original line number	Diff line number	Diff line
		@@ -18,32 +18,98 @@ package android.flags;

		import android.annotation.NonNull;

		import java.util.HashMap;
		import java.util.HashSet;
		import java.util.Map;
		import java.util.Set;

		/**
		* An implementation of {@link FeatureFlags} for testing.
		*
		* Before you read a flag from using this Fake, you must set that flag using
		* {@link #setFlagValue(BooleanFlagBase, boolean)}. This ensures that your tests are deterministic.
		*
		* If you are relying on {@link FeatureFlags#getInstance()} to access FeatureFlags in your code
		* under test, (instead of dependency injection), you can pass an instance of this fake to
		* {@link FeatureFlags#setInstance(FeatureFlags)}. Be sure to call that method again, passing null,
		* to ensure hermetic testing - you don't want static state persisting between your test methods.
		*
		* @hide
		*/
		public class FeatureFlagsFake extends FeatureFlags {
		public FeatureFlagsFake() {
		super();
		private final Map<BooleanFlagBase, Boolean> mFlagValues = new HashMap<>();
		private final Set<BooleanFlagBase> mReadFlags = new HashSet<>();

		public FeatureFlagsFake(IFeatureFlags iFeatureFlags) {
		super(iFeatureFlags);
		}

		@Override
		public boolean isEnabled(@NonNull BooleanFlag flag) {
		return flag.getDefault();
		return requireFlag(flag);
		}

		@Override
		public boolean isEnabled(@NonNull FusedOffFlag flag) {
		return false;
		return requireFlag(flag);
		}

		@Override
		public boolean isEnabled(@NonNull FusedOnFlag flag) {
		return true;
		return requireFlag(flag);
		}

		@Override
		public boolean isCurrentlyEnabled(@NonNull DynamicBooleanFlag flag) {
		return flag.getDefault();
		return requireFlag(flag);
		}

		@Override
		protected void syncInternal(Set<Flag<?>> dirtyFlags) {
		}

		/**
		* Explicitly set a flag's value for reading in tests.
		*
		* You _must_ call this for every flag your code-under-test will read. Otherwise, an
		* {@link IllegalStateException} will be thrown.
		*
		* You are able to set values for {@link FusedOffFlag} and {@link FusedOnFlag}, despite those
		* flags having a fixed value at compile time, since unit tests should still test the state of
		* those flags as both true and false. I.e. a flag that is off might be turned on in a future
		* build or vice versa.
		*
		* You can not call this method _after_ a non-dynamic flag has been read. Non-dynamic flags
		* are held stable in the system, so changing a value after reading would not match
		* real-implementation behavior.
		*
		* Calling this method will trigger any {@link android.flags.FeatureFlags.ChangeListener}s that
		* are registered for the supplied flag if the flag is a {@link DynamicFlag}.
		*
		* @param flag The BooleanFlag that you want to set a value for.
		* @param value The value that the flag should return when accessed.
		*/
		public void setFlagValue(@NonNull BooleanFlagBase flag, boolean value) {
		if (!(flag instanceof DynamicBooleanFlag) && mReadFlags.contains(flag)) {
		throw new RuntimeException(
		"You can not set the value of a flag after it has been read. Tried to set "
		+ flag + " to " + value + " but it already " + mFlagValues.get(flag));
		}
		mFlagValues.put(flag, value);
		if (flag instanceof DynamicBooleanFlag) {
		onFlagChange((DynamicFlag<?>) flag);
		}
		}

		private boolean requireFlag(BooleanFlagBase flag) {
		if (!mFlagValues.containsKey(flag)) {
		throw new IllegalStateException(
		"Tried to access " + flag + " in test but no overrided specified. You must "
		+ "call #setFlagValue for each flag read in a test.");
		}
		mReadFlags.add(flag);

		return mFlagValues.get(flag);
		}

		}