pull in ncruces/go-sqlite3 v0.20.3 with tetratelabs/wazero v1.8.2 (#3574)

vendor/github.com/ncruces/go-sqlite3/vfs/shm_memlk.go

@@ -0,0 +1,55 @@
+//go:build ((freebsd || openbsd || netbsd || dragonfly || illumos) && (386 || arm || amd64 || arm64 || riscv64 || ppc64le) && !sqlite3_nosys) || sqlite3_flock || sqlite3_dotlk
+
+package vfs
+
+import "github.com/ncruces/go-sqlite3/internal/util"
+
+// +checklocks:s.Mutex
+func (s *vfsShm) shmMemLock(offset, n int32, flags _ShmFlag) _ErrorCode {
+	switch {
+	case flags&_SHM_UNLOCK != 0:
+		for i := offset; i < offset+n; i++ {
+			if s.lock[i] {
+				if s.vfsShmParent.lock[i] == 0 {
+					panic(util.AssertErr())
+				}
+				if s.vfsShmParent.lock[i] <= 0 {
+					s.vfsShmParent.lock[i] = 0
+				} else {
+					s.vfsShmParent.lock[i]--
+				}
+				s.lock[i] = false
+			}
+		}
+	case flags&_SHM_SHARED != 0:
+		for i := offset; i < offset+n; i++ {
+			if s.lock[i] {
+				panic(util.AssertErr())
+			}
+			if s.vfsShmParent.lock[i]+1 <= 0 {
+				return _BUSY
+			}
+		}
+		for i := offset; i < offset+n; i++ {
+			s.vfsShmParent.lock[i]++
+			s.lock[i] = true
+		}
+	case flags&_SHM_EXCLUSIVE != 0:
+		for i := offset; i < offset+n; i++ {
+			if s.lock[i] {
+				panic(util.AssertErr())
+			}
+			if s.vfsShmParent.lock[i] != 0 {
+				return _BUSY
+			}
+		}
+		for i := offset; i < offset+n; i++ {
+			s.vfsShmParent.lock[i] = -1
+			s.lock[i] = true
+		}
+	default:
+		panic(util.AssertErr())
+	}
+
+	return _OK
+}