bump ncruces/go-sqlite3 to v0.20.2 (#3524)

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

@@ -0,0 +1,224 @@
+//go:build sqlite3_dotlk
+
+package vfs
+
+import (
+	"context"
+	"errors"
+	"io/fs"
+	"os"
+	"sync"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/tetratelabs/wazero/api"
+)
+
+type vfsShmBuffer struct {
+	shared [][_WALINDEX_PGSZ]byte
+	refs   int // +checklocks:vfsShmBuffersMtx
+
+	lock [_SHM_NLOCK]int16 // +checklocks:Mutex
+	sync.Mutex
+}
+
+var (
+	// +checklocks:vfsShmBuffersMtx
+	vfsShmBuffers    = map[string]*vfsShmBuffer{}
+	vfsShmBuffersMtx sync.Mutex
+)
+
+type vfsShm struct {
+	*vfsShmBuffer
+	mod    api.Module
+	alloc  api.Function
+	free   api.Function
+	path   string
+	shadow [][_WALINDEX_PGSZ]byte
+	ptrs   []uint32
+	stack  [1]uint64
+	lock   [_SHM_NLOCK]bool
+}
+
+func (s *vfsShm) Close() error {
+	if s.vfsShmBuffer == nil {
+		return nil
+	}
+
+	vfsShmBuffersMtx.Lock()
+	defer vfsShmBuffersMtx.Unlock()
+
+	// Unlock everything.
+	s.shmLock(0, _SHM_NLOCK, _SHM_UNLOCK)
+
+	// Decrease reference count.
+	if s.vfsShmBuffer.refs > 0 {
+		s.vfsShmBuffer.refs--
+		s.vfsShmBuffer = nil
+		return nil
+	}
+
+	err := os.Remove(s.path)
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return _IOERR_UNLOCK
+	}
+	delete(vfsShmBuffers, s.path)
+	s.vfsShmBuffer = nil
+	return nil
+}
+
+func (s *vfsShm) shmOpen() _ErrorCode {
+	if s.vfsShmBuffer != nil {
+		return _OK
+	}
+
+	vfsShmBuffersMtx.Lock()
+	defer vfsShmBuffersMtx.Unlock()
+
+	// Find a shared buffer, increase the reference count.
+	if g, ok := vfsShmBuffers[s.path]; ok {
+		s.vfsShmBuffer = g
+		g.refs++
+		return _OK
+	}
+
+	// Create a directory on disk to ensure only this process
+	// uses this path to register a shared memory.
+	err := os.Mkdir(s.path, 0777)
+	if errors.Is(err, fs.ErrExist) {
+		return _BUSY
+	}
+	if err != nil {
+		return _IOERR_LOCK
+	}
+
+	// Add the new shared buffer.
+	s.vfsShmBuffer = &vfsShmBuffer{}
+	vfsShmBuffers[s.path] = s.vfsShmBuffer
+	return _OK
+}
+
+func (s *vfsShm) shmMap(ctx context.Context, mod api.Module, id, size int32, extend bool) (uint32, _ErrorCode) {
+	if size != _WALINDEX_PGSZ {
+		return 0, _IOERR_SHMMAP
+	}
+	if s.mod == nil {
+		s.mod = mod
+		s.free = mod.ExportedFunction("sqlite3_free")
+		s.alloc = mod.ExportedFunction("sqlite3_malloc64")
+	}
+	if rc := s.shmOpen(); rc != _OK {
+		return 0, rc
+	}
+
+	s.Lock()
+	defer s.Unlock()
+	defer s.shmAcquire()
+
+	// Extend shared memory.
+	if int(id) >= len(s.shared) {
+		if !extend {
+			return 0, _OK
+		}
+		s.shared = append(s.shared, make([][_WALINDEX_PGSZ]byte, int(id)-len(s.shared)+1)...)
+	}
+
+	// Allocate shadow memory.
+	if int(id) >= len(s.shadow) {
+		s.shadow = append(s.shadow, make([][_WALINDEX_PGSZ]byte, int(id)-len(s.shadow)+1)...)
+		s.shadow[0][4] = 1 // force invalidation
+	}
+
+	// Allocate local memory.
+	for int(id) >= len(s.ptrs) {
+		s.stack[0] = uint64(size)
+		if err := s.alloc.CallWithStack(ctx, s.stack[:]); err != nil {
+			panic(err)
+		}
+		if s.stack[0] == 0 {
+			panic(util.OOMErr)
+		}
+		clear(util.View(s.mod, uint32(s.stack[0]), _WALINDEX_PGSZ))
+		s.ptrs = append(s.ptrs, uint32(s.stack[0]))
+	}
+
+	return s.ptrs[id], _OK
+}
+
+func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
+	s.Lock()
+	defer s.Unlock()
+
+	switch {
+	case flags&_SHM_LOCK != 0:
+		defer s.shmAcquire()
+	case flags&_SHM_EXCLUSIVE != 0:
+		s.shmRelease()
+	}
+
+	switch {
+	case flags&_SHM_UNLOCK != 0:
+		for i := offset; i < offset+n; i++ {
+			if s.lock[i] {
+				if s.vfsShmBuffer.lock[i] == 0 {
+					panic(util.AssertErr())
+				}
+				if s.vfsShmBuffer.lock[i] <= 0 {
+					s.vfsShmBuffer.lock[i] = 0
+				} else {
+					s.vfsShmBuffer.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.vfsShmBuffer.lock[i]+1 <= 0 {
+				return _BUSY
+			}
+		}
+		for i := offset; i < offset+n; i++ {
+			s.vfsShmBuffer.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.vfsShmBuffer.lock[i] != 0 {
+				return _BUSY
+			}
+		}
+		for i := offset; i < offset+n; i++ {
+			s.vfsShmBuffer.lock[i] = -1
+			s.lock[i] = true
+		}
+	default:
+		panic(util.AssertErr())
+	}
+
+	return _OK
+}
+
+func (s *vfsShm) shmUnmap(delete bool) {
+	if s.vfsShmBuffer == nil {
+		return
+	}
+	defer s.Close()
+
+	s.Lock()
+	s.shmRelease()
+	defer s.Unlock()
+
+	for _, p := range s.ptrs {
+		s.stack[0] = uint64(p)
+		if err := s.free.CallWithStack(context.Background(), s.stack[:]); err != nil {
+			panic(err)
+		}
+	}
+	s.ptrs = nil
+	s.shadow = nil
+}