[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

vendor/github.com/tetratelabs/wazero/internal/sysfs/stat_windows.go

@@ -0,0 +1,120 @@
+//go:build (amd64 || arm64) && windows
+
+package sysfs
+
+import (
+	"io/fs"
+	"syscall"
+
+	experimentalsys "github.com/tetratelabs/wazero/experimental/sys"
+	"github.com/tetratelabs/wazero/sys"
+)
+
+// dirNlinkIncludesDot is false because Windows does not return dot entries.
+//
+// Note: this is only used in tests
+const dirNlinkIncludesDot = false
+
+func lstat(path string) (sys.Stat_t, experimentalsys.Errno) {
+	attrs := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS)
+	// Use FILE_FLAG_OPEN_REPARSE_POINT, otherwise CreateFile will follow symlink.
+	// See https://docs.microsoft.com/en-us/windows/desktop/FileIO/symbolic-link-effects-on-file-systems-functions#createfile-and-createfiletransacted
+	attrs |= syscall.FILE_FLAG_OPEN_REPARSE_POINT
+	return statPath(attrs, path)
+}
+
+func stat(path string) (sys.Stat_t, experimentalsys.Errno) {
+	attrs := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS)
+	return statPath(attrs, path)
+}
+
+func statPath(createFileAttrs uint32, path string) (sys.Stat_t, experimentalsys.Errno) {
+	if len(path) == 0 {
+		return sys.Stat_t{}, experimentalsys.ENOENT
+	}
+	pathp, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return sys.Stat_t{}, experimentalsys.EINVAL
+	}
+
+	// open the file handle
+	h, err := syscall.CreateFile(pathp, 0, 0, nil,
+		syscall.OPEN_EXISTING, createFileAttrs, 0)
+	if err != nil {
+		errno := experimentalsys.UnwrapOSError(err)
+		// To match expectations of WASI, e.g. TinyGo TestStatBadDir, return
+		// ENOENT, not ENOTDIR.
+		if errno == experimentalsys.ENOTDIR {
+			errno = experimentalsys.ENOENT
+		}
+		return sys.Stat_t{}, errno
+	}
+	defer syscall.CloseHandle(h)
+
+	return statHandle(h)
+}
+
+// fdFile allows masking the `Fd` function on os.File.
+type fdFile interface {
+	Fd() uintptr
+}
+
+func statFile(f fs.File) (sys.Stat_t, experimentalsys.Errno) {
+	if osF, ok := f.(fdFile); ok {
+		// Attempt to get the stat by handle, which works for normal files
+		st, err := statHandle(syscall.Handle(osF.Fd()))
+
+		// ERROR_INVALID_HANDLE happens before Go 1.20. Don't fail as we only
+		// use that approach to fill in inode data, which is not critical.
+		//
+		// Note: statHandle uses UnwrapOSError which coerces
+		// ERROR_INVALID_HANDLE to EBADF.
+		if err != experimentalsys.EBADF {
+			return st, err
+		}
+	}
+	return defaultStatFile(f)
+}
+
+func statHandle(h syscall.Handle) (sys.Stat_t, experimentalsys.Errno) {
+	winFt, err := syscall.GetFileType(h)
+	if err != nil {
+		return sys.Stat_t{}, experimentalsys.UnwrapOSError(err)
+	}
+
+	var fi syscall.ByHandleFileInformation
+	if err = syscall.GetFileInformationByHandle(h, &fi); err != nil {
+		return sys.Stat_t{}, experimentalsys.UnwrapOSError(err)
+	}
+
+	var m fs.FileMode
+	if fi.FileAttributes&syscall.FILE_ATTRIBUTE_READONLY != 0 {
+		m |= 0o444
+	} else {
+		m |= 0o666
+	}
+
+	switch { // check whether this is a symlink first
+	case fi.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT != 0:
+		m |= fs.ModeSymlink
+	case winFt == syscall.FILE_TYPE_PIPE:
+		m |= fs.ModeNamedPipe
+	case winFt == syscall.FILE_TYPE_CHAR:
+		m |= fs.ModeDevice | fs.ModeCharDevice
+	case fi.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0:
+		m |= fs.ModeDir | 0o111 // e.g. 0o444 -> 0o555
+	}
+
+	st := sys.Stat_t{}
+	// FileIndex{High,Low} can be combined and used as a unique identifier like inode.
+	// https://learn.microsoft.com/en-us/windows/win32/api/fileapi/ns-fileapi-by_handle_file_information
+	st.Dev = uint64(fi.VolumeSerialNumber)
+	st.Ino = (uint64(fi.FileIndexHigh) << 32) | uint64(fi.FileIndexLow)
+	st.Mode = m
+	st.Nlink = uint64(fi.NumberOfLinks)
+	st.Size = int64(fi.FileSizeHigh)<<32 + int64(fi.FileSizeLow)
+	st.Atim = fi.LastAccessTime.Nanoseconds()
+	st.Mtim = fi.LastWriteTime.Nanoseconds()
+	st.Ctim = fi.CreationTime.Nanoseconds()
+	return st, 0
+}