More VFS API.

Author: ncruces

vfs/api.go

@@ -47,7 +47,7 @@ type File interface {
 // FileLockState extends File to implement the
 // SQLITE_FCNTL_LOCKSTATE file control opcode.
 //
-// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntllockstate
 type FileLockState interface {
 	File
 	LockState() LockLevel
@@ -56,7 +56,7 @@ type FileLockState interface {
 // FileSizeHint extends File to implement the
 // SQLITE_FCNTL_SIZE_HINT file control opcode.
 //
-// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlsizehint
 type FileSizeHint interface {
 	File
 	SizeHint(size int64) error
@@ -65,16 +65,25 @@ type FileSizeHint interface {
 // FileHasMoved extends File to implement the
 // SQLITE_FCNTL_HAS_MOVED file control opcode.
 //
-// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlhasmoved
 type FileHasMoved interface {
 	File
 	HasMoved() (bool, error)
 }
 
+// FileOverwrite extends File to implement the
+// SQLITE_FCNTL_OVERWRITE file control opcode.
+//
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntloverwrite
+type FileOverwrite interface {
+	File
+	Overwrite() error
+}
+
 // FilePowersafeOverwrite extends File to implement the
 // SQLITE_FCNTL_POWERSAFE_OVERWRITE file control opcode.
 //
-// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlpowersafeoverwrite
 type FilePowersafeOverwrite interface {
 	File
 	PowersafeOverwrite() bool
@@ -84,7 +93,7 @@ type FilePowersafeOverwrite interface {
 // FilePowersafeOverwrite extends File to implement the
 // SQLITE_FCNTL_COMMIT_PHASETWO file control opcode.
 //
-// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlcommitphasetwo
 type FileCommitPhaseTwo interface {
 	File
 	CommitPhaseTwo() error
@@ -94,7 +103,7 @@ type FileCommitPhaseTwo interface {
 // SQLITE_FCNTL_BEGIN_ATOMIC_WRITE, SQLITE_FCNTL_COMMIT_ATOMIC_WRITE
 // and SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE file control opcodes.
 //
-// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+// https://www.sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlbeginatomicwrite
 type FileBatchAtomicWrite interface {
 	File
 	BeginAtomicWrite() error

vfs/vfs.go

@@ -309,6 +309,12 @@ func vfsFileControl(ctx context.Context, mod api.Module, pFile uint32, op _Fcntl
 			return vfsErrorCode(err, _IOERR_FSTAT)
 		}
 
+	case _FCNTL_OVERWRITE:
+		if file, ok := file.(FileOverwrite); ok {
+			err := file.Overwrite()
+			return vfsErrorCode(err, _IOERR)
+		}
+
 	case _FCNTL_COMMIT_PHASETWO:
 		if file, ok := file.(FileCommitPhaseTwo); ok {
 			err := file.CommitPhaseTwo()