[Catalyst] Rebind preference immediately when restriction is changed

Bug: 377600992
Flag: com.android.settings.flags.catalyst
Test: testdpc
Change-Id: Iee382afb8395355ee77d604bd399972326557cc0

src/com/android/settings/restriction/UserRestrictions.kt

@@ -0,0 +1,83 @@
+/*
+ * 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.settings.restriction
+
+import android.content.Context
+import android.os.Bundle
+import android.os.IUserRestrictionsListener
+import android.os.UserManager
+import com.android.settingslib.datastore.KeyedDataObservable
+import com.android.settingslib.datastore.KeyedObserver
+import java.util.concurrent.Executor
+import java.util.concurrent.atomic.AtomicBoolean
+
+/** Helper class to monitor user restriction changes. */
+object UserRestrictions {
+    private val observable = KeyedDataObservable<String>()
+
+    private val userRestrictionsListener =
+        object : IUserRestrictionsListener.Stub() {
+            override fun onUserRestrictionsChanged(
+                userId: Int,
+                newRestrictions: Bundle,
+                prevRestrictions: Bundle,
+            ) {
+                // there is no API to remove listener, do a quick check to avoid unnecessary work
+                if (!observable.hasAnyObserver()) return
+
+                val changedKeys = mutableSetOf<String>()
+                val keys = newRestrictions.keySet() + prevRestrictions.keySet()
+                for (key in keys) {
+                    if (newRestrictions.getBoolean(key) != prevRestrictions.getBoolean(key)) {
+                        changedKeys.add(key)
+                    }
+                }
+
+                for (key in changedKeys) observable.notifyChange(key, 0)
+            }
+        }
+
+    private val listenerAdded = AtomicBoolean()
+
+    fun addObserver(context: Context, observer: KeyedObserver<String?>, executor: Executor) {
+        context.addUserRestrictionsListener()
+        observable.addObserver(observer, executor)
+    }
+
+    fun addObserver(
+        context: Context,
+        key: String,
+        observer: KeyedObserver<String>,
+        executor: Executor,
+    ) {
+        context.addUserRestrictionsListener()
+        observable.addObserver(key, observer, executor)
+    }
+
+    private fun Context.addUserRestrictionsListener() {
+        if (listenerAdded.getAndSet(true)) return
+        // surprisingly, there is no way to remove the listener
+        applicationContext
+            .getSystemService(UserManager::class.java)
+            .addUserRestrictionsListener(userRestrictionsListener)
+    }
+
+    fun removeObserver(observer: KeyedObserver<String?>) = observable.removeObserver(observer)
+
+    fun removeObserver(key: String, observer: KeyedObserver<String>) =
+        observable.removeObserver(key, observer)
+}