NotificationThread migration.

core-util/src/main/java/org/signal/core/util/PendingIntentFlags.kt

@@ -0,0 +1,30 @@
+package org.signal.core.util
+
+import android.app.PendingIntent
+import android.os.Build
+
+/**
+ * Wrapper class for lower level API compatibility with the new Pending Intents flags.
+ *
+ * This is meant to be a replacement to using PendingIntent flags independently, and should
+ * end up being the only place in our codebase that accesses these values.
+ *
+ * The "default" value is FLAG_MUTABLE
+ */
+object PendingIntentFlags {
+
+  fun updateCurrent(): Int {
+    return mutable() or PendingIntent.FLAG_UPDATE_CURRENT
+  }
+
+  fun cancelCurrent(): Int {
+    return mutable() or PendingIntent.FLAG_CANCEL_CURRENT
+  }
+
+  /**
+   * The backwards compatible "default" value for pending intent flags.
+   */
+  fun mutable(): Int {
+    return if (Build.VERSION.SDK_INT >= 31) PendingIntent.FLAG_MUTABLE else 0
+  }
+}