FeatureFlag: first implementation

libraries/featureflag/impl/src/main/kotlin/io/element/android/libraries/featureflag/impl/BuildtimeFeatureFlagProvider.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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 io.element.android.libraries.featureflag.impl
+
+import io.element.android.libraries.featureflag.api.Feature
+import io.element.android.libraries.featureflag.api.FeatureFlags
+import javax.inject.Inject
+
+class BuildtimeFeatureFlagProvider @Inject constructor() :
+    FeatureFlagProvider {
+
+    override val priority: Int
+        get() = LOW_PRIORITY
+
+    override suspend fun isFeatureEnabled(feature: Feature): Boolean {
+        return if (feature is FeatureFlags) {
+            when (feature) {
+                FeatureFlags.CollapseRoomStateEvents -> false
+                FeatureFlags.ShowStartChatFlow -> false
+                FeatureFlags.ShowMediaUploadingFlow -> false
+            }
+        } else {
+            false
+        }
+    }
+
+    override fun hasFeature(feature: Feature) = true
+}

libraries/featureflag/impl/src/main/kotlin/io/element/android/libraries/featureflag/impl/DefaultFeatureFlagService.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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 io.element.android.libraries.featureflag.impl
+
+import com.squareup.anvil.annotations.ContributesBinding
+import io.element.android.libraries.di.AppScope
+import io.element.android.libraries.di.SingleIn
+import io.element.android.libraries.featureflag.api.Feature
+import io.element.android.libraries.featureflag.api.FeatureFlagService
+import javax.inject.Inject
+
+@ContributesBinding(AppScope::class)
+@SingleIn(AppScope::class)
+class DefaultFeatureFlagService @Inject constructor(
+    private val providers: Set<@JvmSuppressWildcards FeatureFlagProvider>
+) : FeatureFlagService {
+
+    override suspend fun isFeatureEnabled(feature: Feature): Boolean {
+        return providers.filter { it.hasFeature(feature) }
+            .sortedBy(FeatureFlagProvider::priority)
+            .firstOrNull()
+            ?.isFeatureEnabled(feature)
+            ?: feature.defaultValue
+    }
+
+    override suspend fun setFeatureEnabled(feature: Feature, enabled: Boolean): Boolean {
+        return providers.filterIsInstance(RuntimeFeatureFlagProvider::class.java)
+            .sortedBy(FeatureFlagProvider::priority)
+            .firstOrNull()
+            ?.setFeatureEnabled(feature, enabled)
+            ?.let { true }
+            ?: false
+    }
+}

libraries/featureflag/impl/src/main/kotlin/io/element/android/libraries/featureflag/impl/FeatureFlagProvider.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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 io.element.android.libraries.featureflag.impl
+
+import io.element.android.libraries.featureflag.api.Feature
+
+interface FeatureFlagProvider {
+    val priority: Int
+    suspend fun isFeatureEnabled(feature: Feature): Boolean
+    fun hasFeature(feature: Feature): Boolean
+}
+
+const val LOW_PRIORITY = 0
+const val MEDIUM_PRIORITY = 1
+const val HIGH_PRIORITY = 2
+

libraries/featureflag/impl/src/main/kotlin/io/element/android/libraries/featureflag/impl/PreferencesFeatureFlagProvider.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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 io.element.android.libraries.featureflag.impl
+
+import android.content.Context
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.booleanPreferencesKey
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.preferencesDataStore
+import io.element.android.libraries.di.ApplicationContext
+import io.element.android.libraries.featureflag.api.Feature
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.map
+import javax.inject.Inject
+
+private val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "elementx_featureflag")
+
+class PreferencesFeatureFlagProvider @Inject constructor(@ApplicationContext context: Context) : RuntimeFeatureFlagProvider {
+
+    private val store = context.dataStore
+
+    override val priority: Int
+        get() = MEDIUM_PRIORITY
+
+    override suspend fun setFeatureEnabled(feature: Feature, enabled: Boolean) {
+        store.edit { prefs ->
+            prefs[booleanPreferencesKey(feature.key)] = enabled
+        }
+    }
+
+    override suspend fun isFeatureEnabled(feature: Feature): Boolean {
+        return store.data.map { prefs ->
+            prefs[booleanPreferencesKey(feature.key)] ?: feature.defaultValue
+        }.first()
+    }
+
+    override fun hasFeature(feature: Feature): Boolean {
+        return true
+    }
+}

libraries/featureflag/impl/src/main/kotlin/io/element/android/libraries/featureflag/impl/RuntimeFeatureFlagProvider.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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 io.element.android.libraries.featureflag.impl
+
+import io.element.android.libraries.featureflag.api.Feature
+
+interface RuntimeFeatureFlagProvider : FeatureFlagProvider {
+    suspend fun setFeatureEnabled(feature: Feature, enabled: Boolean)
+}

libraries/featureflag/impl/src/main/kotlin/io/element/android/libraries/featureflag/impl/di/FeatureFlagModule.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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 io.element.android.libraries.featureflag.impl.di
+
+import com.squareup.anvil.annotations.ContributesTo
+import dagger.Module
+import dagger.Provides
+import dagger.multibindings.ElementsIntoSet
+import io.element.android.libraries.core.meta.BuildMeta
+import io.element.android.libraries.di.AppScope
+import io.element.android.libraries.featureflag.impl.BuildtimeFeatureFlagProvider
+import io.element.android.libraries.featureflag.impl.FeatureFlagProvider
+import io.element.android.libraries.featureflag.impl.PreferencesFeatureFlagProvider
+import io.element.android.libraries.featureflag.impl.RuntimeFeatureFlagProvider
+
+@Module
+@ContributesTo(AppScope::class)
+object FeatureFlagModule {
+
+    @Provides
+    fun providesRuntimeFeatureFlagProvider(preferencesFeatureFlagProvider: PreferencesFeatureFlagProvider): RuntimeFeatureFlagProvider {
+        return preferencesFeatureFlagProvider
+    }
+
+    @JvmStatic
+    @Provides
+    @ElementsIntoSet
+    fun providesFeatureFlagProvider(
+        buildMeta: BuildMeta,
+        buildtimeFeatureFlagProvider: BuildtimeFeatureFlagProvider,
+        runtimeFeatureFlagProvider: RuntimeFeatureFlagProvider,
+    ): Set<FeatureFlagProvider> {
+        val providers = HashSet<FeatureFlagProvider>()
+        //TODO change this condition?
+        if (buildMeta.isDebug) {
+            providers.add(runtimeFeatureFlagProvider)
+        } else {
+            providers.add(buildtimeFeatureFlagProvider)
+        }
+        return providers
+    }
+}