Feature flags support in Chooser

A minimalistic replica of the SysUI feature flag infrastructure so the
app could both reuse some of the existing flag infrastructure (local
flag flipping) and have features controlled remotely (through
DeviceConfig).

Bug: 262578843
Test: Manual tests with some injected debug code and local flag flipping
Change-Id: If4be0cfce17e98b978966ea5172f85c5d406f833

2 files changed, 115 insertions, 0 deletions

diff --git a/java/src-debug/com/android/intentresolver/flags/DebugFeatureFlagRepository.kt b/java/src-debug/com/android/intentresolver/flags/DebugFeatureFlagRepository.kt
new file mode 100644
index 00000000..a85e0971
--- /dev/null
+++ b/java/src-debug/com/android/intentresolver/flags/DebugFeatureFlagRepository.kt
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2022 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.intentresolver.flags
+
+import android.util.SparseBooleanArray
+import androidx.annotation.GuardedBy
+import com.android.systemui.flags.BooleanFlag
+import com.android.systemui.flags.FlagManager
+import com.android.systemui.flags.ReleasedFlag
+import com.android.systemui.flags.UnreleasedFlag
+import javax.annotation.concurrent.ThreadSafe
+
+@ThreadSafe
+internal class DebugFeatureFlagRepository(
+    private val flagManager: FlagManager,
+    private val deviceConfig: DeviceConfigProxy,
+) : FeatureFlagRepository {
+    @GuardedBy("self")
+    private val cache = SparseBooleanArray()
+
+    override fun isEnabled(flag: UnreleasedFlag): Boolean = isFlagEnabled(flag)
+
+    override fun isEnabled(flag: ReleasedFlag): Boolean = isFlagEnabled(flag)
+
+    private fun isFlagEnabled(flag: BooleanFlag): Boolean {
+        synchronized(cache) {
+            val idx = cache.indexOfKey(flag.id)
+            if (idx >= 0) return cache.valueAt(idx)
+        }
+        val flagValue = readFlagValue(flag)
+        synchronized(cache) {
+            val idx = cache.indexOfKey(flag.id)
+            // the first read saved in the cache wins
+            if (idx >= 0) return cache.valueAt(idx)
+            cache.put(flag.id, flagValue)
+        }
+        return flagValue
+    }
+
+    private fun readFlagValue(flag: BooleanFlag): Boolean {
+        val localOverride = runCatching {
+            flagManager.isEnabled(flag.id)
+        }.getOrDefault(null)
+        val remoteOverride = deviceConfig.isEnabled(flag)
+
+        // Only check for teamfood if the default is false
+        // and there is no server override.
+        if (remoteOverride == null
+            && !flag.default
+            && localOverride == null
+            && !flag.isTeamfoodFlag
+            && flag.teamfood
+        ) {
+            return flagManager.isTeamfoodEnabled
+        }
+        return localOverride ?: remoteOverride ?: flag.default
+    }
+
+    companion object {
+        // keep in sync with com.android.systemui.flags.Flags
+        private const val TEAMFOOD_FLAG_ID = 1
+
+        private val BooleanFlag.isTeamfoodFlag: Boolean
+            get() = id == TEAMFOOD_FLAG_ID
+
+        private val FlagManager.isTeamfoodEnabled: Boolean
+            get() = runCatching {
+                isEnabled(TEAMFOOD_FLAG_ID) ?: false
+            }.getOrDefault(false)
+    }
+}
diff --git a/java/src-debug/com/android/intentresolver/flags/FeatureFlagRepositoryFactory.kt b/java/src-debug/com/android/intentresolver/flags/FeatureFlagRepositoryFactory.kt
new file mode 100644
index 00000000..4ddb0447
--- /dev/null
+++ b/java/src-debug/com/android/intentresolver/flags/FeatureFlagRepositoryFactory.kt
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2022 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.intentresolver.flags
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import com.android.systemui.flags.FlagManager
+
+class FeatureFlagRepositoryFactory {
+    fun create(context: Context): FeatureFlagRepository =
+        DebugFeatureFlagRepository(
+            FlagManager(context, Handler(Looper.getMainLooper())),
+            DeviceConfigProxy(),
+        )
+}