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VFS improvements.

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This commit is contained in:
Nuno Cruces
2025-07-22 22:41:29 +01:00
parent 75c6744b5b
commit 0399f10c06
8 changed files with 172 additions and 149 deletions
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80
ext/serdes/serdes.go
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@@ -2,9 +2,8 @@
package serdes
import (
"io"
"github.com/ncruces/go-sqlite3"
"github.com/ncruces/go-sqlite3/util/vfsutil"
"github.com/ncruces/go-sqlite3/vfs"
)
@@ -14,16 +13,16 @@ func init() {
vfs.Register(vfsName, sliceVFS{})
}
var fileToOpen = make(chan *sliceFile, 1)
var fileToOpen = make(chan *[]byte, 1)
// Serialize backs up a database into a byte slice.
//
// https://sqlite.org/c3ref/serialize.html
func Serialize(db *sqlite3.Conn, schema string) ([]byte, error) {
var file sliceFile
var file []byte
fileToOpen <- &file
err := db.Backup(schema, "file:serdes.db?vfs="+vfsName)
return file.data, err
return file, err
}
// Deserialize restores a database from a byte slice,
@@ -41,7 +40,7 @@ func Serialize(db *sqlite3.Conn, schema string) ([]byte, error) {
// ["memdb"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/memdb
// ["reader"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/readervfs
func Deserialize(db *sqlite3.Conn, schema string, data []byte) error {
fileToOpen <- &sliceFile{data}
fileToOpen <- &data
return db.Restore(schema, "file:serdes.db?vfs="+vfsName)
}
@@ -53,7 +52,7 @@ func (sliceVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, e
}
select {
case file := <-fileToOpen:
return file, flags | vfs.OPEN_MEMORY, nil
return (*vfsutil.SliceFile)(file), flags | vfs.OPEN_MEMORY, nil
default:
return nil, flags, sqlite3.MISUSE
}
@@ -71,70 +70,3 @@ func (sliceVFS) Access(name string, flag vfs.AccessFlag) (bool, error) {
func (sliceVFS) FullPathname(name string) (string, error) {
return name, nil
}
type sliceFile struct{ data []byte }
func (f *sliceFile) ReadAt(b []byte, off int64) (n int, err error) {
if d := f.data; off < int64(len(d)) {
n = copy(b, d[off:])
}
if n == 0 {
err = io.EOF
}
return
}
func (f *sliceFile) WriteAt(b []byte, off int64) (n int, err error) {
if d := f.data; off > int64(len(d)) {
f.data = append(d, make([]byte, off-int64(len(d)))...)
}
d := append(f.data[:off], b...)
if len(d) > len(f.data) {
f.data = d
}
return len(b), nil
}
func (f *sliceFile) Size() (int64, error) {
return int64(len(f.data)), nil
}
func (f *sliceFile) Truncate(size int64) error {
if d := f.data; size < int64(len(d)) {
f.data = d[:size]
}
return nil
}
func (f *sliceFile) SizeHint(size int64) error {
if d := f.data; size > int64(len(d)) {
f.data = append(d, make([]byte, size-int64(len(d)))...)
}
return nil
}
func (*sliceFile) Close() error { return nil }
func (*sliceFile) Sync(flag vfs.SyncFlag) error { return nil }
func (*sliceFile) Lock(lock vfs.LockLevel) error { return nil }
func (*sliceFile) Unlock(lock vfs.LockLevel) error { return nil }
func (*sliceFile) CheckReservedLock() (bool, error) {
// notest // OPEN_MEMORY
return false, nil
}
func (*sliceFile) SectorSize() int {
// notest // IOCAP_POWERSAFE_OVERWRITE
return 0
}
func (*sliceFile) DeviceCharacteristics() vfs.DeviceCharacteristic {
return vfs.IOCAP_ATOMIC |
vfs.IOCAP_SAFE_APPEND |
vfs.IOCAP_SEQUENTIAL |
vfs.IOCAP_POWERSAFE_OVERWRITE |
vfs.IOCAP_SUBPAGE_READ
}