From 6b49840d7c5593fefc4cd7324df6dc180cb9fbee Mon Sep 17 00:00:00 2001
From: Mark Raynsford <code@io7m.com>
Date: Mon, 20 Jan 2025 11:47:27 +0000
Subject: [PATCH] Work around a low-frequency crash relating to fragment
 parameters (2).

---
 .../viewer/preview/BookPreviewActivity.kt     | 23 +++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/simplified-viewer-preview/src/main/java/org/librarysimplified/viewer/preview/BookPreviewActivity.kt b/simplified-viewer-preview/src/main/java/org/librarysimplified/viewer/preview/BookPreviewActivity.kt
index 5e57c8b39..311ddf85a 100644
--- a/simplified-viewer-preview/src/main/java/org/librarysimplified/viewer/preview/BookPreviewActivity.kt
+++ b/simplified-viewer-preview/src/main/java/org/librarysimplified/viewer/preview/BookPreviewActivity.kt
@@ -115,9 +115,28 @@ class BookPreviewActivity : AppCompatActivity(R.layout.activity_book_preview) {
 
     this.loadingProgress.max = 100
 
-    this.feedEntry =
-      this.intent.getSerializableExtra(EXTRA_ENTRY) as FeedEntry.FeedEntryOPDS
+    val intent = this.intent
+    if (intent == null) {
+      this.logger.warn("BookPreviewActivity lacks an intent!")
+      this.finish()
+      return
+    }
+
+    val extras = intent.extras
+    if (extras == null) {
+      this.logger.warn("BookPreviewActivity intent lacks extras!")
+      this.finish()
+      return
+    }
+
+    val entry = extras.getSerializable(EXTRA_ENTRY) as FeedEntry.FeedEntryOPDS?
+    if (entry == null) {
+      this.logger.warn("BookPreviewActivity intent lacks OPDS entry!")
+      this.finish()
+      return
+    }
 
+    this.feedEntry = entry
     MDC.put(MDCKeys.BOOK_TITLE, this.feedEntry.feedEntry.title)
     MDC.put(MDCKeys.BOOK_ID, this.feedEntry.feedEntry.id)
     MDCKeys.put(MDCKeys.BOOK_PUBLISHER, this.feedEntry.feedEntry.publisher)