From 81b66ad7e324dda72abc293433ecdaf4cf55c3a6 Mon Sep 17 00:00:00 2001
From: kim <89579420+NyaaaWhatsUpDoc@users.noreply.github.com>
Date: Tue, 14 Jan 2025 18:30:55 +0000
Subject: update ncruces/go-sqlite3 v0.21.3 -> v0.22.0, gruf/go-ffmpreg v0.6.4
 -> v0.6.5 (#3646)

---
 vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

(limited to 'vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go')

diff --git a/vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go b/vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go
index 5f4f5d108..76e6888e1 100644
--- a/vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go
+++ b/vendor/github.com/ncruces/go-sqlite3/vfs/shm_bsd.go
@@ -178,7 +178,7 @@ func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 	s.Lock()
 	defer s.Unlock()
 
-	// Check if we could obtain/release the lock locally.
+	// Check if we can obtain/release locks locally.
 	rc := s.shmMemLock(offset, n, flags)
 	if rc != _OK {
 		return rc
@@ -187,6 +187,8 @@ func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 	// Obtain/release the appropriate file locks.
 	switch {
 	case flags&_SHM_UNLOCK != 0:
+		// Relasing a shared lock decrements the counter,
+		// but may leave parts of the range still locked.
 		begin, end := offset, offset+n
 		for i := begin; i < end; i++ {
 			if s.vfsShmParent.lock[i] != 0 {
@@ -201,14 +203,22 @@ func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 		}
 		return rc
 	case flags&_SHM_SHARED != 0:
-		rc = osReadLock(s.File, _SHM_BASE+int64(offset), int64(n))
+		// Acquiring a new shared lock on the file is only necessary
+		// if there was a new shared lock in the range.
+		for i := offset; i < offset+n; i++ {
+			if s.vfsShmParent.lock[i] == 1 {
+				rc = osReadLock(s.File, _SHM_BASE+int64(offset), int64(n))
+				break
+			}
+		}
 	case flags&_SHM_EXCLUSIVE != 0:
+		// Acquiring an exclusive lock on the file is always necessary.
 		rc = osWriteLock(s.File, _SHM_BASE+int64(offset), int64(n))
 	default:
 		panic(util.AssertErr())
 	}
 
-	// Release the local lock we had acquired.
+	// Release the local locks we had acquired.
 	if rc != _OK {
 		s.shmMemLock(offset, n, flags^(_SHM_UNLOCK|_SHM_LOCK))
 	}
-- 
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