From 0e172e015e18cac27a774657511abd7de6fb9c95 Mon Sep 17 00:00:00 2001
From: yumoqing <yumoqing@gmail.com>
Date: Fri, 3 Jul 2026 08:18:33 +0800
Subject: [PATCH] fix: add file magic number verification to diagnose
 corruption

---
 Sources/PlayerBridge.swift | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Sources/PlayerBridge.swift b/Sources/PlayerBridge.swift
index 5dcf961..1c2805c 100644
--- a/Sources/PlayerBridge.swift
+++ b/Sources/PlayerBridge.swift
@@ -271,7 +271,15 @@ final class PlayerBridge: ObservableObject {
             let exists = FileManager.default.fileExists(atPath: path)
             let readable = FileManager.default.isReadableFile(atPath: path)
             let fileSize = (try? FileManager.default.attributesOfItem(atPath: path)[.size] as? Int) ?? 0
-            diagLog("Local file check: exists=\(exists) readable=\(readable) size=\(fileSize)")
+            // 读前4字节验证文件不是空的/损坏的
+            var magic: UInt32 = 0
+            if let fh = try? FileHandle(forReadingFrom: item.url) {
+                if let d = try? fh.read(upToCount: 4), d.count >= 4 {
+                    magic = d.withUnsafeBytes { $0.load(as: UInt32.self) }
+                }
+                try? fh.close()
+            }
+            diagLog("Local file check: exists=\(exists) readable=\(readable) size=\(fileSize) magic=\(String(format:"%08X", magic))")
         }
         
         // 先清除旧的 KVO，避免野指针