Refactor things to use pwritev and preadv rather pwritev64 and preadv64

Author: simlay

library/std/src/sys/pal/unix/fd.rs

@@ -230,16 +230,7 @@ impl FileDesc {
         Ok(ret as usize)
     }
 
-    // We support old MacOS and iOS versions that do not have `preadv`. There is
-    // no `syscall` possible in these platform.
-    #[cfg(any(
-        all(target_os = "android", target_pointer_width = "32"),
-        target_os = "ios", // ios 14.0
-        target_os = "tvos", // tvos 14.0
-        target_os = "macos", // macos 11.0
-        target_os = "watchos", // watchos 7.0
-        target_os = "visionos", // visionos 1.0
-    ))]
+    #[cfg(all(target_os = "android", target_pointer_width = "32"))]
     pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
         super::weak::weak!(fn preadv64(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
 
@@ -259,6 +250,33 @@ impl FileDesc {
         }
     }
 
+    // We support old MacOS, iOS, watchOS, tvOS and visionOS versions that do not have `preadv`.
+    // There is no `syscall` possible in these platform for following apple versions:
+    // ios 14.0
+    // tvos 14.0
+    // macos 11.0
+    // watchos 7.0
+    // visionos 1.0
+    #[cfg(target_vendor = "apple")]
+    pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
+        super::weak::weak!(fn preadv(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
+
+        match preadv.get() {
+            Some(preadv) => {
+                let ret = cvt(unsafe {
+                    preadv(
+                        self.as_raw_fd(),
+                        bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec,
+                        cmp::min(bufs.len(), max_iov()) as libc::c_int,
+                        offset as _,
+                    )
+                })?;
+                Ok(ret as usize)
+            }
+            None => io::default_read_vectored(|b| self.read_at(b, offset), bufs),
+        }
+    }
+
     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
         let ret = cvt(unsafe {
             libc::write(
@@ -387,16 +405,7 @@ impl FileDesc {
         Ok(ret as usize)
     }
 
-    // We support old MacOS and iOS versions that do not have `pwritev`. There is
-    // no `syscall` possible in these platform.
-    #[cfg(any(
-        all(target_os = "android", target_pointer_width = "32"),
-        target_os = "ios", // ios 14.0
-        target_os = "tvos", // tvos 14.0
-        target_os = "macos", // macos 11.0
-        target_os = "watchos", // watchos 7.0
-        target_os = "visionos", // visionos 1.0
-    ))]
+    #[cfg( all(target_os = "android", target_pointer_width = "32"))]
     pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
         super::weak::weak!(fn pwritev64(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
 
@@ -416,6 +425,33 @@ impl FileDesc {
         }
     }
 
+    // We support old MacOS, iOS, watchOS, tvOS and visionOS versions that do not have `pwritev`. 
+    // There is no `syscall` possible in these platform for following apple versions:
+    // ios 14.0
+    // tvos 14.0
+    // macos 11.0
+    // watchos 7.0
+    // visionos 1.0
+    #[cfg(target_vendor = "apple")]
+    pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
+        super::weak::weak!(fn pwritev(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize);
+
+        match pwritev.get() {
+            Some(pwritev) => {
+                let ret = cvt(unsafe {
+                    pwritev(
+                        self.as_raw_fd(),
+                        bufs.as_ptr() as *const libc::iovec,
+                        cmp::min(bufs.len(), max_iov()) as libc::c_int,
+                        offset as _,
+                    )
+                })?;
+                Ok(ret as usize)
+            }
+            None => io::default_write_vectored(|b| self.write_at(b, offset), bufs),
+        }
+    }
+
     #[cfg(not(any(
         target_env = "newlib",
         target_os = "solaris",