[lucenenet] branch master updated: BUG: Lucene.Net.Store.SharingNativeFSLock: Allow other processes (such as RAMDirectory) to read the lock file, only set file sharing to None in IsLocked() to provoke the sharing exception. Fixes #356.

[nightowl888]

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nightowl888 pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
     new 10b326a  BUG: Lucene.Net.Store.SharingNativeFSLock: Allow other 
processes (such as RAMDirectory) to read the lock file, only set file sharing 
to None in IsLocked() to provoke the sharing exception. Fixes #356.
10b326a is described below

commit 10b326a850570b4d25fa837f85083ba1eb34d0be
Author: Shad Storhaug <s...@shadstorhaug.com>
AuthorDate: Sun Sep 27 03:12:05 2020 +0700

    BUG: Lucene.Net.Store.SharingNativeFSLock: Allow other processes (such as 
RAMDirectory) to read the lock file, only set file sharing to None in 
IsLocked() to provoke the sharing exception. Fixes #356.
---
 src/Lucene.Net/Store/NativeFSLockFactory.cs | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/Lucene.Net/Store/NativeFSLockFactory.cs 
b/src/Lucene.Net/Store/NativeFSLockFactory.cs
index e76ba23..86d258d 100644
--- a/src/Lucene.Net/Store/NativeFSLockFactory.cs
+++ b/src/Lucene.Net/Store/NativeFSLockFactory.cs
@@ -139,7 +139,7 @@ namespace Lucene.Net.Store
 
             return FileSupport.GetFileIOExceptionHResult(provokeException: 
(fileName) =>
             {
-                using (var lockStream = new FileStream(fileName, 
FileMode.OpenOrCreate, FileAccess.Write, FileShare.None, 1, FileOptions.None))
+                using (var lockStream = new FileStream(fileName, 
FileMode.OpenOrCreate, FileAccess.Write, FileShare.Read, 1, FileOptions.None))
                 // Try to get an exclusive lock on the file - this should 
throw an IOException with the current platform's HResult value for FileShare 
violation
                 using (var stream = new FileStream(fileName, FileMode.Open, 
FileAccess.Write, FileShare.None, 1, FileOptions.None))
                 {
@@ -288,7 +288,8 @@ namespace Lucene.Net.Store
                 var success = false;
                 try
                 {
-                    channel = new FileStream(path, FileMode.Create, 
FileAccess.Write, FileShare.None);
+                    // LUCENENET: Allow read access for the RAMDirectory to be 
able to copy the lock file.
+                    channel = new FileStream(path, FileMode.Create, 
FileAccess.Write, FileShare.Read);
 
                     success = true;
                 }
@@ -408,7 +409,7 @@ namespace Lucene.Net.Store
 
         public override string ToString()
         {
-            return "{nameof(FallbackNativeFSLock)}@{path}";
+            return $"{nameof(FallbackNativeFSLock)}@{path}";
         }
     }
 
@@ -454,7 +455,15 @@ namespace Lucene.Net.Store
                 throw new IOException("Found regular file where directory 
expected: " + lockDir.FullName);
             }
 
-            return new FileStream(path, mode, FileAccess.Write, 
FileShare.None, 1, mode == FileMode.Open ? FileOptions.None : 
FileOptions.DeleteOnClose);
+            return new FileStream(
+                path,
+                mode,
+                FileAccess.Write,
+                // LUCENENET: Allow read access of OpenOrCreate for the 
RAMDirectory to be able to copy the lock file.
+                // For the Open case, set to FileShare.None to force a file 
share exception in IsLocked().
+                share: mode == FileMode.Open ? FileShare.None : FileShare.Read,
+                bufferSize: 1,
+                options: mode == FileMode.Open ? FileOptions.None : 
FileOptions.DeleteOnClose);
         }
 
         public override bool Obtain()