From c833d5ef3bd8fedf465977c396784dc3ca9ff2de Mon Sep 17 00:00:00 2001
From: Zlatin Balevsky <zlatinb@gmail.com>
Date: Mon, 29 Aug 2022 13:37:19 +0100
Subject: [PATCH] retry hashing on FileNotFoundExceptions, GitHub issue #167

---
 .../main/groovy/com/muwire/core/files/FileHasher.groovy    | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/core/src/main/groovy/com/muwire/core/files/FileHasher.groovy b/core/src/main/groovy/com/muwire/core/files/FileHasher.groovy
index fd763c587..46aa44310 100644
--- a/core/src/main/groovy/com/muwire/core/files/FileHasher.groovy
+++ b/core/src/main/groovy/com/muwire/core/files/FileHasher.groovy
@@ -87,6 +87,13 @@ class FileHasher {
 
                 byte[] hashList = output.toByteArray()
                 return InfoHash.fromHashList(hashList)
+            } catch (FileNotFoundException weird) {
+                if (file.exists()) {
+                    // this is apparently possible on some systems while the file is being used
+                    // by another process, see GitHub issue 167. So we try again.
+                    Thread.sleep(10)
+                } else
+                    break // give up
             } catch (InternalError bad) {
                 // nothing we can but try again.  Happens on jre 18.0.1
                 log.log(Level.SEVERE,"internal error while hashing", bad)