Rollup merge of #151991 - Ayush1325:uefi-split-path, r=joboet

std: sys: pal: uefi: os: Implement split_paths

- Tested using OVMF on QEMU

@rustbot label +O-UEFI
cc @nicholasbishop

Author: JonathanBrouwer

library/std/src/sys/pal/uefi/os.rs

@@ -2,7 +2,6 @@ use r_efi::efi::protocols::{device_path, loaded_image_device_path};
 
 use super::{helpers, unsupported_err};
 use crate::ffi::{OsStr, OsString};
-use crate::marker::PhantomData;
 use crate::os::uefi::ffi::{OsStrExt, OsStringExt};
 use crate::path::{self, PathBuf};
 use crate::{fmt, io};
@@ -38,16 +37,37 @@ pub fn chdir(p: &path::Path) -> io::Result<()> {
     if r.is_error() { Err(io::Error::from_raw_os_error(r.as_usize())) } else { Ok(()) }
 }
 
-pub struct SplitPaths<'a>(!, PhantomData<&'a ()>);
+pub struct SplitPaths<'a> {
+    data: crate::os::uefi::ffi::EncodeWide<'a>,
+    must_yield: bool,
+}
 
-pub fn split_paths(_unparsed: &OsStr) -> SplitPaths<'_> {
-    panic!("unsupported")
+pub fn split_paths(unparsed: &OsStr) -> SplitPaths<'_> {
+    SplitPaths { data: unparsed.encode_wide(), must_yield: true }
 }
 
 impl<'a> Iterator for SplitPaths<'a> {
     type Item = PathBuf;
+
     fn next(&mut self) -> Option<PathBuf> {
-        self.0
+        let must_yield = self.must_yield;
+        self.must_yield = false;
+
+        let mut in_progress = Vec::new();
+        for b in self.data.by_ref() {
+            if b == PATHS_SEP {
+                self.must_yield = true;
+                break;
+            } else {
+                in_progress.push(b)
+            }
+        }
+
+        if !must_yield && in_progress.is_empty() {
+            None
+        } else {
+            Some(PathBuf::from(OsString::from_wide(&in_progress)))
+        }
     }
 }
 

library/std/tests/env.rs

@@ -59,6 +59,23 @@ fn split_paths_unix() {
     assert!(check_parse("/:/usr/local", &mut ["/", "/usr/local"]));
 }
 
+#[test]
+#[cfg(target_os = "uefi")]
+fn split_paths_uefi() {
+    use std::path::PathBuf;
+
+    fn check_parse(unparsed: &str, parsed: &[&str]) -> bool {
+        split_paths(unparsed).collect::<Vec<_>>()
+            == parsed.iter().map(|s| PathBuf::from(*s)).collect::<Vec<_>>()
+    }
+
+    assert!(check_parse("", &mut [""]));
+    assert!(check_parse(";;", &mut ["", "", ""]));
+    assert!(check_parse(r"fs0:\", &mut [r"fs0:\"]));
+    assert!(check_parse(r"fs0:\;", &mut [r"fs0:\", ""]));
+    assert!(check_parse(r"fs0:\;fs0:\boot\", &mut [r"fs0:\", r"fs0:\boot\"]));
+}
+
 #[test]
 #[cfg(unix)]
 fn join_paths_unix() {