Import some stuff about Push and notification from Element Android - WIP

libraries/core/src/main/kotlin/io/element/android/libraries/core/cache/CircularCache.kt

@@ -0,0 +1,41 @@
+/*
+ * 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.core.cache
+
+/**
+ * A FIFO circular buffer of T.
+ * This class is not thread safe.
+ */
+class CircularCache<T : Any>(cacheSize: Int, factory: (Int) -> Array<T?>) {
+
+    companion object {
+        inline fun <reified T : Any> create(cacheSize: Int) = CircularCache(cacheSize) { Array<T?>(cacheSize) { null } }
+    }
+
+    private val cache = factory(cacheSize)
+    private var writeIndex = 0
+
+    fun contains(value: T): Boolean = cache.contains(value)
+
+    fun put(value: T) {
+        if (writeIndex == cache.size) {
+            writeIndex = 0
+        }
+        cache[writeIndex] = value
+        writeIndex++
+    }
+}