Reuse Metadata if possible to save syscalls.

src/hostcalls_impl/fs.rs

@@ -756,9 +756,9 @@ fn fd_filestat_get_impl(file: &std::fs::File) -> Result<host::__wasi_filestat_t>
 
  let metadata = file.metadata().map_err(convert_err)?;
  Ok(host::__wasi_filestat_t {
- st_dev: hostcalls_impl::device_id(file).map_err(convert_err)?,
- st_ino: hostcalls_impl::file_serial_no(file).map_err(convert_err)?,
- st_nlink: hostcalls_impl::num_hardlinks(file)
+ st_dev: hostcalls_impl::device_id(file, &metadata).map_err(convert_err)?,
+ st_ino: hostcalls_impl::file_serial_no(file, &metadata).map_err(convert_err)?,
+ st_nlink: hostcalls_impl::num_hardlinks(file, &metadata)
  .map_err(convert_err)?
  .try_into()
  .map_err(|_| host::__WASI_EOVERFLOW)?, // u64 doesn't fit into u32
@@ -767,15 +767,15 @@ fn fd_filestat_get_impl(file: &std::fs::File) -> Result<host::__wasi_filestat_t>
  .accessed()
  .map_err(convert_err)
  .and_then(timestamp)?,
- st_ctim: hostcalls_impl::change_time(file)
+ st_ctim: hostcalls_impl::change_time(file, &metadata)
  .map_err(convert_err)?
  .try_into()
  .map_err(|_| host::__WASI_EOVERFLOW)?, // i64 doesn't fit into u64
  st_mtim: metadata
  .modified()
  .map_err(convert_err)
  .and_then(timestamp)?,
- st_filetype: hostcalls_impl::filetype(file).map_err(convert_err)?,
+ st_filetype: hostcalls_impl::filetype(&metadata).map_err(convert_err)?,
  })
 }
 

src/sys/unix/hostcalls_impl/fs.rs

@@ -9,7 +9,7 @@ use crate::sys::host_impl;
 use crate::{host, wasm32, Result};
 use nix::libc::{self, c_long, c_void, off_t};
 use std::ffi::CString;
-use std::fs::File;
+use std::fs::{File, Metadata};
 use std::io;
 use std::os::unix::fs::FileExt;
 use std::os::unix::prelude::{AsRawFd, FromRawFd};
@@ -357,24 +357,24 @@ pub(crate) fn path_rename(
  }
 }
 
-pub(crate) fn num_hardlinks(file: &File) -> io::Result<u64> {
+pub(crate) fn num_hardlinks(_file: &File, metadata: &Metadata) -> io::Result<u64> {
  use std::os::unix::fs::MetadataExt;
- Ok(file.metadata()?.nlink())
+ Ok(metadata.nlink())
 }
 
-pub(crate) fn device_id(file: &File) -> io::Result<u64> {
+pub(crate) fn device_id(_file: &File, metadata: &Metadata) -> io::Result<u64> {
  use std::os::unix::fs::MetadataExt;
- Ok(file.metadata()?.dev())
+ Ok(metadata.dev())
 }
 
-pub(crate) fn file_serial_no(file: &File) -> io::Result<u64> {
+pub(crate) fn file_serial_no(_file: &File, metadata: &Metadata) -> io::Result<u64> {
  use std::os::unix::fs::MetadataExt;
- Ok(file.metadata()?.ino())
+ Ok(metadata.ino())
 }
 
-pub(crate) fn filetype(file: &File) -> io::Result<host::__wasi_filetype_t> {
+pub(crate) fn filetype(metadata: &Metadata) -> io::Result<host::__wasi_filetype_t> {
  use std::os::unix::fs::FileTypeExt;
- let ftype = file.metadata()?.file_type();
+ let ftype = metadata.file_type();
  let ret = if ftype.is_file() {
  host::__WASI_FILETYPE_REGULAR_FILE
  } else if ftype.is_dir() {
@@ -396,10 +396,9 @@ pub(crate) fn filetype(file: &File) -> io::Result<host::__wasi_filetype_t> {
  Ok(ret)
 }
 
-pub(crate) fn change_time(file: &File) -> io::Result<i64> {
- use std::convert::TryInto;
+pub(crate) fn change_time(_file: &File, metadata: &Metadata) -> io::Result<i64> {
  use std::os::unix::fs::MetadataExt;
- Ok(file.metadata()?.ctime())
+ Ok(metadata.ctime())
 }
 
 pub(crate) fn fd_filestat_set_times(

src/sys/windows/hostcalls_impl/fs.rs

@@ -7,7 +7,7 @@ use crate::sys::errno_from_host;
 use crate::sys::fdentry_impl::determine_type_rights;
 use crate::sys::host_impl;
 use crate::{host, Result};
-use std::fs::File;
+use std::fs::{File, Metadata};
 use std::io::{self, Seek, SeekFrom};
 use std::os::windows::fs::FileExt;
 use std::os::windows::prelude::{AsRawHandle, FromRawHandle};
@@ -173,28 +173,28 @@ pub(crate) fn path_rename(
  unimplemented!("path_rename")
 }
 
-pub(crate) fn num_hardlinks(file: &File) -> io::Result<u64> {
+pub(crate) fn num_hardlinks(file: &File, _metadata: &Metadata) -> io::Result<u64> {
  Ok(winx::file::get_fileinfo(file)?.nNumberOfLinks.into())
 }
 
-pub(crate) fn device_id(file: &File) -> io::Result<u64> {
+pub(crate) fn device_id(file: &File, _metadata: &Metadata) -> io::Result<u64> {
  Ok(winx::file::get_fileinfo(file)?.dwVolumeSerialNumber.into())
 }
 
-pub(crate) fn file_serial_no(file: &File) -> io::Result<u64> {
+pub(crate) fn file_serial_no(file: &File, _metadata: &Metadata) -> io::Result<u64> {
  let info = winx::file::get_fileinfo(file)?;
  let high = info.nFileIndexHigh;
  let low = info.nFileIndexLow;
  let no = ((high as u64) << 32) | (low as u64);
  Ok(no)
 }
 
-pub(crate) fn change_time(file: &File) -> io::Result<i64> {
+pub(crate) fn change_time(file: &File, _metadata: &Metadata) -> io::Result<i64> {
  winx::file::change_time(file)
 }
 
-pub(crate) fn filetype(file: &File) -> io::Result<host::__wasi_filetype_t> {
- let ftype = file.metadata()?.file_type();
+pub(crate) fn filetype(metadata: &Metadata) -> io::Result<host::__wasi_filetype_t> {
+ let ftype = metadata.file_type();
  let ret = if ftype.is_file() {
  host::__WASI_FILETYPE_REGULAR_FILE
  } else if ftype.is_dir() {