[1/n] Creates OptPropFactory to simplify OptIn and OptOut properties

Allow to handle OptIn and OptOut properties in lazy and simpler
way.

Bug: 318801382
Test: atest WmTests:OptPropFactoryTest

Change-Id: Id9d0e8892daa7dc8129eaee44d59e74de045ea3c
diff --git a/services/core/java/com/android/server/wm/utils/OptPropFactory.java b/services/core/java/com/android/server/wm/utils/OptPropFactory.java
new file mode 100644
index 0000000..8201969b
--- /dev/null
+++ b/services/core/java/com/android/server/wm/utils/OptPropFactory.java
@@ -0,0 +1,233 @@
+/*
+ * Copyright (C) 2024 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 com.android.server.wm.utils;
+
+import static java.lang.Boolean.FALSE;
+import static java.lang.Boolean.TRUE;
+
+import android.annotation.IntDef;
+import android.annotation.NonNull;
+import android.content.pm.PackageManager;
+import android.util.Slog;
+
+import java.util.function.BooleanSupplier;
+
+/**
+ * Utility class which helps with handling with properties to opt-in or
+ * opt-out a specific feature.
+ */
+public class OptPropFactory {
+
+    @NonNull
+    private final PackageManager mPackageManager;
+
+    @NonNull
+    private final String mPackageName;
+
+    /**
+     * Object responsible to handle optIn and optOut properties.
+     *
+     * @param packageManager The PackageManager reference
+     * @param packageName    The name of the package.
+     */
+    public OptPropFactory(@NonNull PackageManager packageManager, @NonNull String packageName) {
+        mPackageManager = packageManager;
+        mPackageName = packageName;
+    }
+
+    /**
+     * Creates an OptProp for the given property
+     *
+     * @param propertyName The name of the property.
+     * @return The OptProp for the given property
+     */
+    @NonNull
+    public OptProp create(@NonNull String propertyName) {
+        return OptProp.create(
+                () -> mPackageManager.getProperty(propertyName, mPackageName).getBoolean(),
+                propertyName);
+    }
+
+    /**
+     * Creates an OptProp for the given property behind a gate condition.
+     *
+     * @param propertyName  The name of the property.
+     * @param gateCondition If this resolves to false, the property is unset. This is evaluated at
+     *                      every interaction with the OptProp.
+     * @return The OptProp for the given property
+     */
+    @NonNull
+    public OptProp create(@NonNull String propertyName, @NonNull BooleanSupplier gateCondition) {
+        return OptProp.create(
+                () -> mPackageManager.getProperty(propertyName, mPackageName).getBoolean(),
+                propertyName,
+                gateCondition);
+    }
+
+    @FunctionalInterface
+    private interface ThrowableBooleanSupplier {
+        boolean get() throws Exception;
+    }
+
+    public static class OptProp {
+
+        private static final int VALUE_UNSET = -2;
+        private static final int VALUE_UNDEFINED = -1;
+        private static final int VALUE_FALSE = 0;
+        private static final int VALUE_TRUE = 1;
+
+        @IntDef(prefix = {"VALUE_"}, value = {
+                VALUE_UNSET,
+                VALUE_UNDEFINED,
+                VALUE_FALSE,
+                VALUE_TRUE,
+        })
+        @interface OptionalValue {}
+
+        private static final String TAG = "OptProp";
+
+        // The condition is evaluated every time the OptProp state is accessed.
+        @NonNull
+        private final BooleanSupplier mCondition;
+
+        // This is evaluated only once in the lifetime of an OptProp.
+        @NonNull
+        private final ThrowableBooleanSupplier mValueSupplier;
+
+        @NonNull
+        private final String mPropertyName;
+
+        @OptionalValue
+        private int mValue = VALUE_UNDEFINED;
+
+        private OptProp(@NonNull ThrowableBooleanSupplier valueSupplier,
+                @NonNull String propertyName,
+                @NonNull BooleanSupplier condition) {
+            mValueSupplier = valueSupplier;
+            mPropertyName = propertyName;
+            mCondition = condition;
+        }
+
+        @NonNull
+        private static OptProp create(@NonNull ThrowableBooleanSupplier valueSupplier,
+                @NonNull String propertyName) {
+            return new OptProp(valueSupplier, propertyName, () -> true);
+        }
+
+        @NonNull
+        private static OptProp create(@NonNull ThrowableBooleanSupplier valueSupplier,
+                @NonNull String propertyName, @NonNull BooleanSupplier condition) {
+            return new OptProp(valueSupplier, propertyName, condition);
+        }
+
+        /**
+         * @return {@code true} when the guarding condition is {@code true} and the property has
+         * been explicitly set to {@code true}. {@code false} otherwise. The guarding condition is
+         * evaluated every time this method is invoked.
+         */
+        public boolean isTrue() {
+            return mCondition.getAsBoolean() && getValue() == VALUE_TRUE;
+        }
+
+        /**
+         * @return {@code true} when the guarding condition is {@code true} and the property has
+         * been explicitly set to {@code false}. {@code false} otherwise. The guarding condition is
+         * evaluated every time this method is invoked.
+         */
+        public boolean isFalse() {
+            return mCondition.getAsBoolean() && getValue() == VALUE_FALSE;
+        }
+
+        /**
+         * Returns {@code true} when the following conditions are met:
+         * <ul>
+         *     <li>{@code gatingCondition} doesn't evaluate to {@code false}
+         *     <li>App developers didn't opt out with a component {@code property}
+         *     <li>App developers opted in with a component {@code property} or an OEM opted in with
+         *     a per-app override
+         * </ul>
+         *
+         * <p>This is used for the treatments that are enabled only on per-app basis.
+         */
+        public boolean shouldEnableWithOverrideAndProperty(boolean overrideValue) {
+            if (!mCondition.getAsBoolean()) {
+                return false;
+            }
+            if (getValue() == VALUE_FALSE) {
+                return false;
+            }
+            return getValue() == VALUE_TRUE || overrideValue;
+        }
+
+        /**
+         * Returns {@code true} when the following conditions are met:
+         * <ul>
+         *     <li>{@code gatingCondition} doesn't evaluate to {@code false}
+         *     <li>App developers didn't opt out with a component {@code property}
+         *     <li>OEM opted in with a per-app override
+         * </ul>
+         *
+         * <p>This is used for the treatments that are enabled based with the heuristic but can be
+         * disabled on per-app basis by OEMs or app developers.
+         */
+        public boolean shouldEnableWithOptInOverrideAndOptOutProperty(
+                boolean overrideValue) {
+            if (!mCondition.getAsBoolean()) {
+                return false;
+            }
+            return getValue() != VALUE_FALSE && overrideValue;
+        }
+
+        /**
+         * Returns {@code true} when the following conditions are met:
+         * <ul>
+         *     <li>{@code gatingCondition} doesn't resolve to {@code false}
+         *     <li>OEM didn't opt out with a per-app override
+         *     <li>App developers didn't opt out with a component {@code property}
+         * </ul>
+         *
+         * <p>This is used for the treatments that are enabled based with the heuristic but can be
+         * disabled on per-app basis by OEMs or app developers.
+         */
+        public boolean shouldEnableWithOptOutOverrideAndProperty(boolean overrideValue) {
+            if (!mCondition.getAsBoolean()) {
+                return false;
+            }
+            return getValue() != VALUE_FALSE && !overrideValue;
+        }
+
+        @OptionalValue
+        private int getValue() {
+            if (mValue == VALUE_UNDEFINED) {
+                try {
+                    final Boolean value = mValueSupplier.get();
+                    if (TRUE.equals(value)) {
+                        mValue = VALUE_TRUE;
+                    } else if (FALSE.equals(value)) {
+                        mValue = VALUE_FALSE;
+                    } else {
+                        mValue = VALUE_UNSET;
+                    }
+                } catch (Exception e) {
+                    Slog.w(TAG, "Cannot read opt property " + mPropertyName);
+                    mValue = VALUE_UNSET;
+                }
+            }
+            return mValue;
+        }
+    }
+}
diff --git a/services/tests/wmtests/src/com/android/server/wm/utils/OptPropFactoryTest.java b/services/tests/wmtests/src/com/android/server/wm/utils/OptPropFactoryTest.java
new file mode 100644
index 0000000..004de1f
--- /dev/null
+++ b/services/tests/wmtests/src/com/android/server/wm/utils/OptPropFactoryTest.java
@@ -0,0 +1,286 @@
+/*
+ * Copyright (C) 2024 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 com.android.server.wm.utils;
+
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
+
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.content.pm.PackageManager;
+import android.platform.test.annotations.Presubmit;
+
+import androidx.test.filters.SmallTest;
+
+import com.android.server.wm.utils.OptPropFactory.OptProp;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import java.util.function.BooleanSupplier;
+
+/**
+ * Build/Install/Run:
+ * atest WmTests:OptPropFactoryTest
+ */
+@SmallTest
+@Presubmit
+public class OptPropFactoryTest {
+
+    private PackageManager mPackageManager;
+    private OptPropFactory mOptPropFactory;
+
+    @Before
+    public void setUp() {
+        mPackageManager = mock(PackageManager.class);
+        mOptPropFactory = new OptPropFactory(mPackageManager, "");
+    }
+
+    @Test
+    public void optProp_laziness() throws PackageManager.NameNotFoundException {
+        initPropAs(/* propertyValue */ true);
+        // When OptPropBuilder is created the PackageManager is not used
+        verify(mPackageManager, never()).getProperty(anyString(), anyString());
+
+        // Accessing the value multiple times only uses PackageManager once
+        final OptProp optProp = createOptProp();
+        optProp.isTrue();
+        optProp.isFalse();
+
+        verify(mPackageManager).getProperty(anyString(), anyString());
+    }
+
+    @Test
+    public void optProp_withSetValueTrue() throws PackageManager.NameNotFoundException {
+        initPropAs(/* propertyValue */ true);
+
+        final OptProp optProp = createOptProp();
+
+        assertTrue(optProp.isTrue());
+        assertFalse(optProp.isFalse());
+    }
+
+    @Test
+    public void optProp_withSetValueFalse() throws PackageManager.NameNotFoundException {
+        initPropAs(/* propertyValue */ false);
+
+        final OptProp optProp = createOptProp();
+
+        assertFalse(optProp.isTrue());
+        assertTrue(optProp.isFalse());
+    }
+
+    @Test
+    public void optProp_withSetValueWithConditionFalse()
+            throws PackageManager.NameNotFoundException {
+        initPropAs(/* propertyValue */ true);
+
+        final OptProp optProp = createOptProp(() -> false);
+
+        assertFalse(optProp.isTrue());
+        assertFalse(optProp.isFalse());
+    }
+
+    @Test
+    public void optProp_withUnsetValue() {
+        final OptProp optProp = createOptProp();
+
+        assertFalse(optProp.isTrue());
+        assertFalse(optProp.isFalse());
+    }
+
+    @Test
+    public void optProp_isUnsetWhenPropertyIsNotPresent()
+            throws PackageManager.NameNotFoundException {
+        initPropAsWithException();
+        // Property is unset
+        final OptProp optUnset = createOptProp();
+        assertFalse(optUnset.isTrue());
+        assertFalse(optUnset.isFalse());
+    }
+
+    @Test
+    public void optProp_shouldEnableWithOverrideAndProperty()
+            throws PackageManager.NameNotFoundException {
+        // Property is unset
+        final OptProp optUnset = createOptProp(() -> false);
+        assertFalse(optUnset.shouldEnableWithOverrideAndProperty(/* override */ true));
+
+        // The value is the override one
+        final OptProp optUnsetOn = createOptProp();
+        assertTrue(optUnsetOn.shouldEnableWithOverrideAndProperty(/* override */ true));
+        assertFalse(optUnsetOn.shouldEnableWithOverrideAndProperty(/* override */ false));
+
+        // Property is set to true
+        initPropAs(true);
+        final OptProp optTrue = createOptProp(() -> false);
+        assertFalse(optTrue.shouldEnableWithOverrideAndProperty(/* override */ true));
+
+        final OptProp optTrueOn = createOptProp(() -> true);
+        assertTrue(optTrueOn.shouldEnableWithOverrideAndProperty(/* override */ true));
+        assertTrue(optTrueOn.shouldEnableWithOverrideAndProperty(/* override */ false));
+
+        // Property is set to false
+        initPropAs(false);
+        final OptProp optFalse = createOptProp(() -> false);
+        assertFalse(optFalse.shouldEnableWithOverrideAndProperty(/* override */ true));
+
+        final OptProp optFalseOn = createOptProp();
+        assertFalse(optFalseOn.shouldEnableWithOverrideAndProperty(/* override */ true));
+        assertFalse(optFalseOn.shouldEnableWithOverrideAndProperty(/* override */ false));
+    }
+
+    @Test
+    public void optProp_shouldEnableWithOptInOverrideAndOptOutProperty()
+            throws PackageManager.NameNotFoundException {
+        // Property is unset
+        final OptProp optUnset = createOptProp(() -> false);
+        assertFalse(optUnset.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ true));
+
+        final OptProp optUnsetOn = createOptProp();
+        assertTrue(optUnsetOn.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ true));
+        assertFalse(
+                optUnsetOn.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ false));
+
+        // Property is set to true
+        initPropAs(true);
+        final OptProp optTrue = createOptProp(() -> false);
+        assertFalse(optTrue.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ true));
+
+        // Is the value of the override
+        final OptProp optTrueOn = createOptProp(() -> true);
+        assertTrue(optTrueOn.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ true));
+        assertFalse(optTrueOn.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ false));
+
+        // Property is set to false
+        initPropAs(false);
+        final OptProp optFalse = createOptProp(() -> false);
+        assertFalse(optFalse.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ true));
+
+        // Always false ahatever is the value of the override
+        final OptProp optFalseOn = createOptProp();
+        assertFalse(optFalseOn.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ true));
+        assertFalse(
+                optFalseOn.shouldEnableWithOptInOverrideAndOptOutProperty(/* override */ false));
+    }
+
+    @Test
+    public void optProp_shouldEnableWithOptOutOverrideAndProperty()
+            throws PackageManager.NameNotFoundException {
+        // Property is unset
+        final OptProp optUnset = createOptProp(() -> false);
+        assertFalse(optUnset.shouldEnableWithOptOutOverrideAndProperty(/* override */ true));
+
+        // Is the negate of the override value
+        final OptProp optUnsetOn = createOptProp();
+        assertTrue(optUnsetOn.shouldEnableWithOptOutOverrideAndProperty(/* override */ false));
+        assertFalse(optUnsetOn.shouldEnableWithOptOutOverrideAndProperty(/* override */ true));
+
+        // Property is set to true
+        initPropAs(true);
+        final OptProp optTrue = createOptProp(() -> false);
+        assertFalse(optTrue.shouldEnableWithOptOutOverrideAndProperty(/* override */ true));
+
+        // Is the negate of the override value
+        final OptProp optTrueOn = createOptProp(() -> true);
+        assertTrue(optTrueOn.shouldEnableWithOptOutOverrideAndProperty(/* override */ false));
+        assertFalse(optTrueOn.shouldEnableWithOptOutOverrideAndProperty(/* override */ true));
+
+        // Property is set to false
+        initPropAs(false);
+        final OptProp optFalse = createOptProp(() -> false);
+        assertFalse(optFalse.shouldEnableWithOptOutOverrideAndProperty(/* override */ true));
+
+        // Always false ahatever is the value of the override
+        final OptProp optFalseOn = createOptProp();
+        assertFalse(optFalseOn.shouldEnableWithOptOutOverrideAndProperty(/* override */ true));
+        assertFalse(optFalseOn.shouldEnableWithOptOutOverrideAndProperty(/* override */ false));
+    }
+
+    @Test
+    public void optProp_gateConditionIsInvokedOnlyOncePerInvocation()
+            throws PackageManager.NameNotFoundException {
+
+        final FakeGateCondition trueCondition = new FakeGateCondition(/* returnValue */ true);
+        final OptProp optProp = createOptProp(trueCondition);
+
+        optProp.shouldEnableWithOverrideAndProperty(/* override value */ true);
+        assertEquals(1, trueCondition.getInvocationCount());
+        trueCondition.clearInvocationCount();
+
+        initPropAs(true);
+        optProp.shouldEnableWithOptInOverrideAndOptOutProperty(/* override value */ true);
+        assertEquals(1, trueCondition.getInvocationCount());
+        trueCondition.clearInvocationCount();
+
+        optProp.shouldEnableWithOptOutOverrideAndProperty(/* override value */ true);
+        assertEquals(1, trueCondition.getInvocationCount());
+        trueCondition.clearInvocationCount();
+    }
+
+    private void initPropAs(boolean propertyValue) throws PackageManager.NameNotFoundException {
+        Mockito.clearInvocations(mPackageManager);
+        final PackageManager.Property prop = new PackageManager.Property(
+                "", /* value */ propertyValue, "", "");
+        when(mPackageManager.getProperty(anyString(), anyString())).thenReturn(prop);
+    }
+
+    private void initPropAsWithException() throws PackageManager.NameNotFoundException {
+        Mockito.clearInvocations(mPackageManager);
+        when(mPackageManager.getProperty("", "")).thenThrow(
+                new PackageManager.NameNotFoundException());
+    }
+
+    private OptProp createOptProp() {
+        return mOptPropFactory.create("");
+    }
+
+    private OptProp createOptProp(BooleanSupplier condition) {
+        return mOptPropFactory.create("", condition);
+    }
+
+    private static class FakeGateCondition implements BooleanSupplier {
+
+        private int mInvocationCount = 0;
+        private final boolean mReturnValue;
+
+        private FakeGateCondition(boolean returnValue) {
+            mReturnValue = returnValue;
+        }
+
+        @Override
+        public boolean getAsBoolean() {
+            mInvocationCount++;
+            return mReturnValue;
+        }
+
+        int getInvocationCount() {
+            return mInvocationCount;
+        }
+
+        void clearInvocationCount() {
+            mInvocationCount = 0;
+        }
+
+    }
+}