Add a shared library for setting flags in SysUI.

This adds the FlagManager class which currently has 3 methods:
- #getFlagsFuture
- #setFlagValue
- #eraseFlag

The first makes an async call to SystemUI to retrieve the flags
it knows about. It returns a collection of Flag objects from which
one can get the id, type, and default values.

The other two are fairly self-explanatory, sending intents to
SystemUI telling to set or erase flags. Any app calling these
methods must have the FLAGS_PERMISSION defined in the FlagManager
library.

Only boolean flags are supported at the moment.

Bug: 203548827
Test: manual
Change-Id: Id15ff481edcb83c67ce4cdad6cdda27d28a40652

packages/SystemUI/Android.bp

@@ -50,6 +50,17 @@ java_library {
     srcs: ["src/com/android/systemui/EventLogTags.logtags"],
 }
 
+java_library {
+    name: "SystemUI-flags",
+    srcs: [
+        "src/com/android/systemui/flags/Flags.java",
+    ],
+    libs: [
+        "SystemUI-flag-types",
+    ],
+    static_kotlin_stdlib: false,
+}
+
 filegroup {
     name: "ReleaseJavaFiles",
     srcs: [
@@ -116,6 +127,7 @@ android_library {
         "iconloader_base",
         "SystemUI-tags",
         "SystemUI-proto",
+        "SystemUI-flags",
         "monet",
         "dagger2",
         "jsr330",

packages/SystemUI/shared/Android.bp

@@ -45,9 +45,40 @@ android_library {
         ":wm_shell-aidls",
         ":wm_shell_util-sources",
     ],
+    libs: [
+        "SystemUI-flags",
+    ],
     static_libs: [
         "PluginCoreLib",
         "androidx.dynamicanimation_dynamicanimation",
+        "androidx.concurrent_concurrent-futures",
+    ],
+    java_version: "1.8",
+    min_sdk_version: "current",
+}
+
+java_library {
+    name: "SystemUI-flag-types",
+    srcs: [
+        "src/com/android/systemui/flags/Flag.kt",
+    ],
+    static_kotlin_stdlib: false,
+    java_version: "1.8",
+    min_sdk_version: "current",
+}
+
+java_library {
+    name: "SystemUIFlagsLib",
+    srcs: [
+        "src/com/android/systemui/flags/**/*.kt",
+    ],
+    static_kotlin_stdlib: false,
+    libs: [
+        "androidx.concurrent_concurrent-futures",
+        "SystemUI-flags",
+    ],
+    static_libs: [
+        "SystemUI-flag-types",
     ],
     java_version: "1.8",
     min_sdk_version: "current",

packages/SystemUI/shared/src/com/android/systemui/flags/FlagManager.kt

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2021 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.systemui.flags
+
+import android.content.Context
+import android.content.Intent
+import androidx.concurrent.futures.CallbackToFutureAdapter
+import com.google.common.util.concurrent.ListenableFuture
+
+class FlagManager constructor(val context: Context) {
+    companion object {
+        const val RECEIVING_PACKAGE = "com.android.systemui"
+        const val ACTION_SET_FLAG = "com.android.systemui.action.SET_FLAG"
+        const val FLAGS_PERMISSION = "com.android.systemui.permission.FLAGS"
+        const val FIELD_ID = "id"
+        const val FIELD_VALUE = "value"
+    }
+
+    fun getFlagsFuture(): ListenableFuture<Collection<Flag<*>>> {
+        val knownFlagMap = Flags.collectFlags()
+        // Possible todo in the future: query systemui async to actually get the known flag ids.
+        return CallbackToFutureAdapter.getFuture(
+            CallbackToFutureAdapter.Resolver {
+                completer: CallbackToFutureAdapter.Completer<Collection<Flag<*>>> ->
+                completer.set(knownFlagMap.values as Collection<Flag<*>>)
+                "Retrieving Flags"
+            })
+    }
+
+    fun setFlagValue(id: Int, enabled: Boolean) {
+        val intent = createIntent(id)
+        intent.putExtra(FIELD_VALUE, enabled)
+
+        context.sendBroadcast(intent)
+    }
+
+    fun eraseFlag(id: Int) {
+        val intent = createIntent(id)
+
+        context.sendBroadcast(intent)
+    }
+
+    private fun createIntent(id: Int): Intent {
+        val intent = Intent(ACTION_SET_FLAG)
+        intent.setPackage(RECEIVING_PACKAGE)
+        intent.putExtra(FIELD_ID, id)
+
+        return intent
+    }
+}

packages/SystemUI/src-debug/com/android/systemui/flags/FeatureFlagManager.java

@@ -16,6 +16,11 @@
 
 package com.android.systemui.flags;
 
+import static com.android.systemui.flags.FlagManager.ACTION_SET_FLAG;
+import static com.android.systemui.flags.FlagManager.FIELD_ID;
+import static com.android.systemui.flags.FlagManager.FIELD_VALUE;
+import static com.android.systemui.flags.FlagManager.FLAGS_PERMISSION;
+
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -55,11 +60,7 @@ public class FeatureFlagManager implements FlagReader, FlagWriter, Dumpable {
 
     private static final String SYSPROP_PREFIX = "persist.systemui.flag_";
     private static final String FIELD_TYPE = "type";
-    private static final String FIELD_ID = "id";
-    private static final String FIELD_VALUE = "value";
     private static final String TYPE_BOOLEAN = "boolean";
-    private static final String ACTION_SET_FLAG = "com.android.systemui.action.SET_FLAG";
-    private static final String FLAGS_PERMISSION = "com.android.systemui.permission.FLAGS";
     private final SystemPropertiesHelper mSystemPropertiesHelper;
 
     private final Map<Integer, Boolean> mBooleanFlagCache = new HashMap<>();