gotosocial/vendor/github.com/tetratelabs/wazero/sys/stat.go
kim 1e7b32490d
[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/).
2024-05-27 17:46:15 +02:00

107 lines
3.9 KiB
Go

package sys
import "io/fs"
// Inode is the file serial number, or zero if unknown.
//
// Any constant value will invalidate functions that use this for
// equivalence, such as os.SameFile (Stat_t.Ino).
//
// When zero is returned by a `readdir`, some compilers will attempt to
// get a non-zero value with `lstat`. Those using this for darwin's definition
// of `getdirentries` conflate zero `d_fileno` with a deleted file, so skip the
// entry. See /RATIONALE.md for more on this.
type Inode = uint64
// ^-- Inode is a type alias to consolidate documentation and aid in reference
// searches. While only Stat_t is exposed publicly at the moment, this is used
// internally for Dirent and several function return values.
// EpochNanos is a timestamp in epoch nanoseconds, or zero if unknown.
//
// This defines epoch time the same way as Walltime, except this value is
// packed into an int64. Common conversions are detailed in the examples.
type EpochNanos = int64
// Stat_t is similar to syscall.Stat_t, except available on all operating
// systems, including Windows.
//
// # Notes
//
// - This is used for WebAssembly ABI emulating the POSIX `stat` system call.
// Fields included are required for WebAssembly ABI including wasip1
// (a.k.a. wasix) and wasi-filesystem (a.k.a. wasip2). See
// https://pubs.opengroup.org/onlinepubs/9699919799/functions/stat.html
// - Fields here are required for WebAssembly ABI including wasip1
// (a.k.a. wasix) and wasi-filesystem (a.k.a. wasip2).
// - This isn't the same as syscall.Stat_t because wazero supports Windows,
// which doesn't have that type. runtime.GOOS that has this already also
// have inconsistent field lengths, which complicates wasm binding.
// - Use NewStat_t to create this from an existing fs.FileInfo.
// - For portability, numeric fields are 64-bit when at least one platform
// defines it that large.
type Stat_t struct {
// Dev is the device ID of device containing the file.
Dev uint64
// Ino is the file serial number, or zero if not available. See Inode for
// more details including impact returning a zero value.
Ino Inode
// Mode is the same as Mode on fs.FileInfo containing bits to identify the
// type of the file (fs.ModeType) and its permissions (fs.ModePerm).
Mode fs.FileMode
// Nlink is the number of hard links to the file.
//
// Note: This value is platform-specific and often at least one. Linux will
// return 1+N for a directory, where BSD (like Darwin) return 2+N, which
// includes the dot entry.
Nlink uint64
// Size is the length in bytes for regular files. For symbolic links, this
// is length in bytes of the pathname contained in the symbolic link.
Size int64
// Atim is the last data access timestamp in epoch nanoseconds.
Atim EpochNanos
// Mtim is the last data modification timestamp in epoch nanoseconds.
Mtim EpochNanos
// Ctim is the last file status change timestamp in epoch nanoseconds.
Ctim EpochNanos
}
// NewStat_t fills a new Stat_t from `info`, including any runtime.GOOS-specific
// details from fs.FileInfo `Sys`. When `Sys` is already a *Stat_t, it is
// returned as-is.
//
// # Notes
//
// - When already in fs.FileInfo `Sys`, Stat_t must be a pointer.
// - When runtime.GOOS is "windows" Stat_t.Ino will be zero.
// - When fs.FileInfo `Sys` is nil or unknown, some fields not in fs.FileInfo
// are defaulted: Stat_t.Atim and Stat_t.Ctim are set to `ModTime`, and
// are set to ModTime and Stat_t.Nlink is set to 1.
func NewStat_t(info fs.FileInfo) Stat_t {
// Note: Pointer, not val, for parity with Go, which sets *syscall.Stat_t
if st, ok := info.Sys().(*Stat_t); ok {
return *st
}
return statFromFileInfo(info)
}
func defaultStatFromFileInfo(info fs.FileInfo) Stat_t {
st := Stat_t{}
st.Ino = 0
st.Dev = 0
st.Mode = info.Mode()
st.Nlink = 1
st.Size = info.Size()
mtim := info.ModTime().UnixNano() // Set all times to the mod time
st.Atim = mtim
st.Mtim = mtim
st.Ctim = mtim
return st
}